OCS EIS/EA 

MMS 2006-038 

FINAL Programmatic Environmental Assessment

Arctic Ocean Outer Continental Shelf 

Seismic Surveys - 2006 

Author 

Minerals Management Service 

Alaska OCS Region 

June 2006
TABLE OF CONTENTS 

Acronyms and Abbreviations 

I INTRODUCTION, 1 

I.A Background, 1 

I.A.1 Regulatory Framework, 1 

I.A.2 Historical Overview, 2 

I.B Purpose and Need for the Proposed Action, 3 

I.C Scope, Objectives, and Assumptions, 4 

I.D Issues and Concerns, 5 

I.E Overview of Seismic Surveys, 6 

I.E.1 Marine-Streamer 3D and 2D Surveys, 6 

I.E.2 Ocean-Bottom-Cable Seismic Surveys, 7 

I.E.3 High-Resolution Site-Clearance Surveys, 8 

II DESCRIPTION OF THE ALTERNATIVES, 9 

II.A Range of Alternatives, 9 

II.A.1 Alternative I. No Seismic-Survey Permits Issued for Geophysical-Exploration Activities 

(No Action), 10 

II.A.2 Alternative 2. Seismic Surveys for Geophysical-Exploration Activities would be 

Permitted with Existing Alaska OCS Geological and Geophysical Exploration 

Stipulations and Guidelines, 10 

II.A.3 Alternative 3. Seismic Surveys for Geophysical-Exploration Activities would be 

Permitted with Existing Alaska OCS Geological and Geophysical Exploration 

Stipulations and Guidelines and Additional Protective Measures for Marine Mammals, 

including a 120-dB-Specified Exclusion Zone, 10 

II.A.4 Alternative 4. Seismic Surveys for Geophysical-Exploration Activities would be 

Permitted with Existing Alaska OCS Geological and Geophysical Exploration 

Stipulations and Guidelines and Additional Protective Measures for Marine Mammals, 

including a 160-dB Specified-Exclusion Zone, 12 

II.A.5 Alternative 5. Seismic Surveys for Geophysical-Exploration Activities would be 

Permitted with Existing Alaska OCS Geological and Geophysical Exploration 

Stipulations and Guidelines and Additional Protective Measures for Marine Mammals, 

including a 160-dB and 120-dB Specified-Exclusion Zone, 12 

II.A.6 Alternative 6. Seismic Surveys for Geophysical-Exploration Activities would be 

Permitted with Existing Alaska OCS Geological and Geophysical Exploration 

Stipulations and Guidelines and Additional Protective Measures for Marine Mammals, 

including a 180/190-dB Specified-Exclusion Zone, 13 

II.B Evaluation of Alternative, 13 

II.B.1 Alternative Excluded from Further Evaluation, 13 

II.B.2 Alternatives Considered in More Detail, 13 

III EXISTING ENVIRONMENT AND IMPACT ANALYSIS, 16 

III.A Physical Environment, 16 

III.A.1 Physical Oceanography, 16 

III.A.1.a Sea Ice, 17 

 i
III.A.2 Air Quality, 19 

III.B Acoustic Environment, 19 

III.B.1 Existing Environment, 19 

III.B.1.a Ambient Sound, 19 

III.B.1.b Anthropogenic Sound, 20 

III.B.1.c Potential Effect of Climate Change, 22 

III.B.2 Sound Propagation, 22 

III.B.3 Seismic Sound, 23 

III.C Cumulative Activity Scenario, 25 

III.C.1 Marine Seismic Surveys in the Beaufort and Chukchi Seas, 25 

III.C.1.a OCS Seismic-Survey Activities, 25 

III.C.1.b State of Alaska Seismic-Survey Activities, 26 

III.C.1.c Other Seismic-Survey Activities, 26 

III.C.2 Vessel Traffic and Movements, 27 

III.C.3 Air Traffic, 28 

III.C.4 Oil and Gas Development in Federal and State Waters, 28 

III.C.4.a Federal OCS Activities, 28 

III.C.4.b State of Alaska Activities, 29 

III.C.5 Miscellaneous Activities and Factors, 29 

III.C.5.a Subsistence-Harvest Activities, 29 

IIi.C.5.b Military Activities, 29 

III.C.5.c Industrial Development, 30 

III.C.5.d Community Development, 31 

III.C.5.e Climate Change, 31 

III.D Preliminary Screening of Seismic-Survey Activities and Potential Impacts, 31 

III.D.1 Resources Not Considered Further, 32 

III.D.1.a Air Quality, 32 

III.D.1.b Coastal Wetlands, 33 

III.D.1.c Freshwater Fishes, 33 

III.D.1.d Geology and Sediments, 33 

III.D.1.e Terrestrial Mammals, 33 

III.D.1.f Water Quality, 33 

III.D.1.g Aquatic Invasive Species, 34 

III.D.2 Resources to be Evaluated in Greater Detail, 35 

III.E Significant Impact Criteria, 35 

III.E.1 Significance Thresholds for Resource Categories, 35 

III.E.2 Criteria for the Evaluation of the Potential for Significant Effects on Endangered 

Whales, 36 

III.F Biological Resources, 38 

III.F.1 Fish/Fishery Resources and Essential Fish Habitat, 38 

III.F.1.a Introduction, 38 

III.F.1.b Major Surveys of Coastal and Marine Fish Resources and Habitats, 38 

III.F.1.c Fish Resources of Arctic Alaska and Their Ecology, 40 

III.F.1.d Pacific Salmon and Essential Fish Habitat, 42 

III.F.1.d(1) Chinook, Sockeye, and Coho Salmon, 42 

III.F.2.d(2) Pink Salmon, 42 

III.F.1.d(3) Chum Salmon, 44 

III.F.1.d(4) Essential Fish Habitat for Pacific Salmon in Alaska, 45 

III.F.1.d(5) Distribution and Abundance Trends of Pacific Salmon in the Alaska Beaufort Sea, 47 

III.F.1.e Invertebrate Fishery Resources and Fragile Biocenoses, 47 

III.F.1.e(1) Kelp and Macroscopic Algae, 47 

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III.F.1.e(2) Squid and Essential Fish Habitat, 48 

III.F.1.e(3) Snow Crab and Essential Fish Habitat, 48 

III.F.1.f Commercial Fisheries, 49 

III.F.1.g Past and Present Response to Climate Change, 49 

III.F.1.h Data Deficiencies, 51 

III.F.1.i Potential Impacts of the Proposed Action, 51 

III.F.1.i(1) Acoustic Detection and Capabilities, 51 

III.F.1.i(2) Potential Impacts from Airgun Acoustic Emissions, 54 

III.F.1.i(3) Potential Impacts to Essential Fish Habitat, 63 

III.F.1.j Assessment of Alternatives, 64 

III.F.1.k Mitigating Measures, 64 

III.F.1.l Conclusions, 65 

III.F.2 Marine Birds, 66 

III.F.2.a Threatened and Endangered Marine Birds, 65 

III.F.2.a(1) Spectacled Eider (Somateria fischeri), 66 

III.F.2.a(2) Steller’s Eider (Polysticta stelleri), 67 

III.F.2.a(3) Kittlitz’s Murrelet (Brachyramphus brevirostris), 68 

III.F.2.b Other Marine Birds, 68 

III.F.2.b(1) Cliff-nesting Seabirds, 68 

III.F.2.b(2) Bering Sea Breeders and Summer Residents, 69 

III.F.2.b(3) High-Arctic-Associated Seabirds, 70 

III.F.2.b(4) Tundra-Breeding Migrants, 71 

III.F.2.b(5) Waterfowl, 71 

III.F.2.c Impact Assessment, 72 

III.F.2.c(1) Range of Potential Effects, 72 

III.F.2.c(2) Impacts of Alternatives on Threatened and Endangered Species, 76 

III.F.2.c(3) Impacts of Alternatives on Other Marine Birds, 78 

III.F.3 Threatened and Endangered Species of Marine Mammals, 82 

III.F.3.a Background, 82 

III.F.3.b Summary of Pertinent Information about Listed Species that Underlies our Analysis, 83 

III.F.3.b(1) Bowhead Whales, 83 

III.F.3.b(2) Fin Whales, 83 

III.F.3.b(3) Humpback Whales, 84 

III.F.3.c Bowhead Whale, 84 

III.F.3.c(1) Introduction, 84 

III.F.3.c(2) ESA Status of the Western Arctic Stock, 84 

III.F.3.c(3) Population Structure and Current Stock Definitions, 85 

III.F.3.c(4) Past and Current Population Abundance, 86 

III.F.3.c(5) Reproduction, Survival, and Non-Human Sources of Mortality, 86 

IIi.F.3.c(6) Migration, Distribution, and Habitat Use, 87 

III.F.3.c(7) Feeding Behavior, 93 

III.F.3.c(8) Summary, 100 

III.F.3.d Fin Whale, 100 

III.F.3.d(1) Introduction, 100 

III.F.3.d(2) ESA Status, 101 

III.F.3.d(3) Population Structure and Current Stock Definitions, 101 

III.F.3.d(4) Past and Current Population Abundance, 101 

III.F.3.d(5) Reproduction, Survival, and Non-Human-Related Sources of Mortality, 101 

III.F.3.d(6) Migration, Distribution, and Habitat Use, 102 

III.F.3.d(7) Foraging Ecology and Feeding Areas, 104 

III.F.3.e Humpback Whale (Central and Western North Pacific Stocks), 105 

III.F.3.e(1) Introduction, 105 

III.F.3.e(2) ESA Status, 105 

III.F.3.e(3) Population Structure and Current Stock Definitions, 105 

III.F.3.e(4) Past and Current Population Abundance in the North Pacific, 106 

III.F.3.e(5) Reproduction, Survival, and Non-Human-Related Sources of Mortality, 107 

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III.F.3.e(6) Migration, Distribution, and Habitat Use, 107 

III.F.3.e(7) Feeding Behavior, 109 

III.F.3.f Impact Assessment Overview, 109 

III.F.3.f(1) Principles and Assumptions Underlying Analyses of Potential Effects, 109 

III.F.3.f(2) Potential Pathways of Impact from Seismic Surveys, 112 

III.F.3.f(3) Potential Effects of Noise and Disturbance from Proposed Seismic Surveys, 113 

III.F.3.f(4) Potential Effects of Noise and Disturbance from Proposed Actions on Bowhead, Fin, and 

Humpback Whales, 113 

III.F.3.f(5) Potential Exposure to Seismic-Survey Activities in the Proposed Action Area, 118 

III.F.3.f(6) Potential Effects from Seismic Surveys, 120 

III.F.3.f(7) Effects of Noise from Icebreakers, 129 

III.F.3.f(8) Effects from Other Vessel Traffic Associated with Seismic Surveys, 130 

III.F.3.f(9) Effects from Aircraft Traffic, 131 

III.F.3.f(10) Areas and Situations Where Potential Impacts are Likely to be Greater than Typical, 132 

III.F.3.f(11) Summary of Noise Effects Associated with Seismic Surveys, 135 

III.F.3.f(12) Effects from Small Oil Spills Associated with Seismic Surveys, 136 

III.F.3.f(13) Evaluation of the Context and Intensity of the Proposed Action Relative to Bowhead 

Whales, 137 

III.F.3.f(14) Conclusions about Potential Effects of Seismic Surveys on Bowhead Whales, 138 

III.F.3.f(15) -Potential Effects of Seismic Survey-Related Noise and Disturbance on Fin and 

Humpback Whales, 141 

III.F.3.g Mitigation Measures Necessary for Bowhead Whales, 142 

III.F.3.h Impact Assessment of Alternatives, 142 

III.F.3.h(1) Alternative 1, 142 

III.F.3.h(2) Alternatives 3 through 6, 142 

III.F.4 Other Marine Mammals, 143 

III.F.4.a Affected Species and their Habitat, 144 

III.F.4.a(1) Pinnipeds, 144 

III.F.4.a(2) Cetaceans, 147 

III.F.4.a(3) Marine Fissipeds (Polar Bear), 151 

III.F.4.b Impact Assessment, 151 

III.F.4.b(1) Pinnipeds, 153 

IIi.F.4.b(2) Cetaceans, 155 

III.F.4.b(3) Marine Fissipeds (Polar Bear), 158 

III.F.4.b(4) Conclusions, 159 

III.F.4.c Impact Assessment of Alternatives, 159 

III.F.4.c(1) Alternative 1, 160 

III.F.4.c(2) Alternatives 3 through 6, 160 

III.G Community Setting, 164 

III.G.1 Economy, 164 

III.G.1.a Affected Environment, 164 

III.G.1.b Impact Assessment, 165 

III.G.2 Subsistence Environment, 165 

III.G.2.a Cultural Importance, 166 

III.G.2.b Socioeconomic Importance, 166 

III.G.2.c Community Harvest Patterns and Traditions, 167 

III.G.2.d Concerns about Climate Change, 168 

III.G.2.e Impact Assessment Overview, 169 

III.G.2.e(1) Subsistence-Harvest Patterns, 169 

III.G.2.e(2) Subsistence Resources, 170 

III.G.2.e(3) Traditional Knowledge, 172 

III.G.2.e(4) Conclusions, 173 

III.G.2.f Impacts of Alternatives on Subsistence-Harvest Patterns, 175 

III.G.2.f(1) Alternative 1 (No Action), 175 

III.G.2.f(2) Alternatives 3, 4, 5, and 6, 175 

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III.G.3 Sociocultural Environment, 178 

III.G.3.a Background, 178 

III.G.3.b Sociocultural Community Profiles, 180 

III.G.3.b(1) Kaktovik, 180 

III.G.3.b(2) Nuiqsut, 180 

III.G.3.b(3) Barrow, 181 

III.G.3.b(4) Atqasuk, 181 

III.G.3.b(5) Wainwright, 181 

III.G.3.b(6) Point Lay, 182 

III.G.3.b(7) Point Hope, 182 

III.G.3.c Impact Assessment Overview, 183 

III.G.3.c(1) Social Organization, 183 

III.G.3.c(2) Cultural Values, 183 

III.G.3.c(3) Subsistence and Social Health, 184 

III.G.3.c(4) Alaska Native Views, 184 

III.G.3.c(5) Conclusions, 185 

III.G.3.d Impacts of Alternatives on Socioculture, 185 

III.G.3.d(1) Alternative 1 (No Action), 185 

III.G.3.d(2) Alternatives 3,4, 5, and 6, 185 

III.G.4 Archaeological Resources, 186 

III.G.4.a Overview, 186 

III.G.4.b Offshore Prehistoric Resources, 186 

III.G.4.c Offshore Historic Resources, 187 

III.G.4.d Onshore Prehistoric and Historic Resources, 187 

III.G.4.e Impact Assessment, 187 

III.G.5 Land Use Plans and Coastal Zone Management, 188 

III.G.5.a Land Status and Use, 188 

III.G.5.b Coastal Zone Management, 189 

III.G.6 Environmental Justice, 189 

III.G.6.a Overview, 189 

III.G.6.b Demographics, 190 

III.G.6.b(1) Race, 190 

III.G.6.b(2) Income, 190 

III.G.6.b(3) Consumption of Fish and Game, 190 

III.G.6.c Impact Assessment Overview, 191 

III.G.6.d Impacts of Alternatives, 192 

III.G.6.d(1) Alternative 1, 192 

III.G.6.d(2) Alternatives 3, 4, 5, and 6, 192 

III.G.6.d(3) Standard, Potential, and Ongoing Studies and Mitigation Initiatives, 192 

III.H Cumulative Impacts Analysis, 194 

III.H.1 Fish/Fishery Resources and Essential Fish Habitat, 195 

III.H.1.a OCS Seismic-Survey Activities, 194 

III.H.1.b Seismic-Survey Activities in Alaska State Waters, 195 

III.H.1.c Other Seismic-Survey Activities, 195 

III.H.1.d Vessel Traffic and Movements, 196 

III.H.1.e Air Traffic, 196 

III.H.1.f Oil and Gas Exploration and Development Activities in Federal Waters, 196 

III.H.1.g Oil and Gas Exploration and Development in State Waters, 196 

III.H.1.h Subsistence-Harvest Activities, 196 

III.H.1.i Military Activities, 197 

III.H.1.j Industrial Development, 197 

III.H.1.k Community Development, 197 

III.H.1.l Climate Change, 197 

III.H.1.m Conclusion, 198 

III.H.2 Marine Birds, 198 

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III.H.2.a Seismic-Survey Activities, 198 

III.H.2.b Vessel Traffic and Movements, 198 

III.H.2.c Air Traffic, 198 

III.H.2.d Conclusion, 198 

III.H.3 Threatened and Endangered Marine Mammals, 199 

III.H.3.a Bowhead Whales, 199 

III.H.3.a(1) Introductory Information Relevant in Evaluation and Interpretation of Potential 

Cumulative Effects on Bowheads, 200 

III.H.3.a(2) Activities Considered, 200 

III.H.3.b Fin Whales, 212 

III.H.3.b(1) Past Commercial Hunting, 212 

III.H.3.b(2) Other Past, Present, and Foreseeable Human Impacts, 212 

III.H.3.c Humpback Whales, 213 

III.H.4 Nonthreatened and Nonendangered Marine Mammals, 215 

III.H.4.a Air Traffic, 215 

III.H.4.b Climate Change, 215 

III.H.4.c Community Development, 216 

III.H.4.d Chemical Introduction (oil and fuel spills and industrial chemicals), 216 

IIi.H.4.e Commercial and Recreational Fishing, 216 

III.H.4.f Industrial Development and Related Noise, 216 

III.H.4.g Vessel-Traffic Noise, 219 

III.H.4.h Other Noise Sources, 219 

III.H.4.i Subsistence Harvest, 220 

III.H.4.j Military Activities, 220 

III.H.4.k Conclusions, 221 

III.H.5 Subsistence-Harvest Patterns, 221 

III.H.5.a Marine Seismic Surveys, 221 

III.H.5.b Vessel Traffic and Movements, 221 

III.H.5.c Aircraft Traffic, 221 

III.H.5.d Oil and Gas Development in Federal, State, and Canadian Waters, 222 

III.H.5.e Miscellaneous Activities, Factors, and Industrial Development, 222 

III.H.5.f Effects of Noise and Traffic Disturbances, 222 

III.H.5.g Native Views Concerning Cumulative Effects on Subsistence-Harvest Patterns, 223 

III.H.5.g(1) Nuiqsut’s Views on Cumulative Effects, 223 

III.H.5.g(2) Kaktovik’s Views on Cumulative Effects, 223 

III.H.5.g(3) Barrow’s Views on Cumulative Effects, 224 

III.H.5.g(4) Chukchi Sea Communities’ Views on Cumulative Effects, 224 

III.H.5.h Climate Change, 224 

III.H.5.i Conclusion, 225 

III.H.6 Sociocultural Systems, 225 

III.H.6.a Social Organization and Cultural Values, 225 

III.H.7 Environmental Justice, 226 

III.H.8 Archaeological Resources, 227 

IV SUMMARY OF FINDINGS, MITIGATION MEASURES, AND

RECOMMENDATIONS, 229 

IV.A Mitigation Measures Incorporated into the Alternatives, 229 

IV.A.1 Standard MMS G&G Permit Stipulations, 229 

IV.A.2 Measures to Mitigate Seismic Exposure to Marine Mammals, 230 

IV.B Additional Mitigation Measures to be Considered in the Alternatives, 231 

V SELECTED ALTERNATIVE AND MITIGATION MEASURES, 234 

V.A Description of the Selected Alternatives, 234 

V.B Description of Mitigation Measures, 234 

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VI CONSULTATION AND COORDINATION, 239 

VII LIST OF PREPARERS AND CONTRIBUTORS, 241 

VIII LITERATURE CITED, 242 

Tables 

I.C-1 Assumptions used to Identify and Analyze the Impacts Associated with Conducting 2D and 3D 

Seismic Surveys. 

II.B-1 Comparative General Ranking of the Feasibility Characteristics of each Alternative to be 

Considered Further. 

III.B-1 A Comparison of Most Common Sound Levels from Various Sources. 

III.C-1 Projected Number of State of Alaska and OCS Seismic Surveys in the Beaufort and Chukchi Seas 

between 2006 and 2010. 

III.C-2 Future Lease Sale Activities in Federal and State Waters of the Beaufort and Chukchi seas, and 

Vicinity. 

III.D-1 Preliminary Screening of Potential Impacts of Marine Seismic Surveys on Beaufort and Chukchi 

seas Resources. 

III.D-2 Examples of Seismic Operations Potential to Emit. 

III.D-3 Emission Factors and Operating Assumptions used in the PEA’s Air Quality Assessment. 

III.D-4 Prevention of Significant Deterioration (PSD) Standards. 

III.D-5 Potential to Emit for the Liberty Development and Production Facility. 

III.F-1 Fish Resources of Arctic Alaska. 

III.F-2 Arctic Fish Occurrence in Coastal and Marine Waters of the Chukchi and Beaufort Seas. 

III.F-3 Reduction in Fish Catch Rates as a Result of Seismic Survey Activity. 

III.G-1 Population Counts for Native Subsistence-based Communities in the Arctic Ecoregion; Total 

American Indian and Alaskan Native Population Percentages. 

III.G-2 Median Household, Median Family, Per-Capita Incomes; Number of People in Poverty; Percent of 

the Total Borough or Native Subsistence-based Community Population. 

Maps 

Map 1 Arctic Ocean Seismic Proposed Action Area. 

Figures 

I.E-1 Simple Illustration of a Marine Seismic Survey Operation using Streamers. 

III.A-1 Circulation over Chukchi and Beaufort Seas. 

III.B-1 Typical 3D Marine Seismic Survey Array Configuration. 

III.C-1 Arctic Ocean Outer Continental Shelf 2D Seismic Survey Data Collected from 1970 through 

1979. 

III.C-2 Arctic Ocean Outer Continental Shelf 2D Seismic Survey Data Collected from 1980 through 

1989. 

III.C-3 Arctic Ocean Outer Continental Shelf 2D Seismic Survey Data Collected from 1990 through 

2004. 

III.C-4 Beaufort Sea Existing Leases, January 2006. 

III.C-5 Previously Leased Blocks in the Chukchi Sea Program Area – All Relinquished. 

III.C-6 North Slope Oil and Gas Activities and Discoveries, as of January 2006. 

III.F-1 Spectacled Eider Critical Habitat at Ledyard Bay and Molting Migration Distances from Shore. 

III.F-2 Spectacled Eider Critical Habitat Area. 

III.F-3 Approximate Areas used by Murres when Foraging from Breeding Colonies in Summer and by 

Juvenile and Attendant Males During the Post-nesting period. 

III.F-4 Sea Duck Fall Migration Distances from Shore. 

III.F-5 Approximate Distribution of the Western Arctic Stock Bowhead Whales. 

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III.F-6 Counts of Bowhead Whales in the Beaufort Sea taken by the Bowhead Whale Aerial Survey 

Project. 

III.F-7 Counts of Bowhead Whales in the Chukchi Sea taken by the Bowhead Whale Aerial Survey 

Project. 

III.F-8 Approximate distribution of fin whales in the eastern North Pacific. 

III.F-9 Approximate distribution of humpback whales in the western North Pacific. 

III.F-10 Estimated zone of avoidance by bowhead whales if four deep seismic surveys operated 

simultaneously in the Beaufort Sea, assuming 20 km avoidance by bowhead whales and 15 miles 

(24 km) between vessels. 

III.F-11 Estimated zone of avoidance by bowhead whales if four deep seismic surveys operated 

simultaneously in the Chukchi Sea, assuming 20 km avoidance by bowhead whales and 15 miles 

(24 km) between vessels. 

APPENDICES 

Appendix A Existing Minerals Management Service Geological and Geophysical Permit Stipulations 

for Oil and Gas Activities in Alaska OCS Waters 

Appendix B Profiles of the Families of Fish and Selected Species that Occur in the Alaska Arctic 

Ocean 

Appendix C Subsistence-Harvest Activities in Inupiat Communities In and Adjacent to the Beaufort 

and Chukchi Seas Proposed Action Area 

Appendix D Responses to Comments on the Draft Programmatic Environmental Assessment Arctic 

Ocean Outer Continental Shelf Seismic Surveys, 2006 

 viii
List of Acronyms, Initialisms, Abbreviations, and Symbols 

AAC Alaska Administrative Code 

ACMP Alaska Coastal Management Program 

ACQCR Air Quality Control Regions 

ADF&G Alaska Department of Fish and Game 

AEWC Alaska Eskimo Whaling Commission 

AGL above ground level (altitude) 

AMAP Arctic Monitoring and Assessment Program 

ANCSA Alaska Native Claims Settlement Act 

ANILCA Alaska National Interest Lands Conservation Act 

ASL above sea level (altitude) 

bbl barrel(s) 

BCB Seas Bering-Chukchi-Beaufort Seas stock of bowhead whales 

BE Biological Evaluation 

BLM Bureau of Land Management 

BO Biological Opinion 

BWASP Bowhead Whale Aerial Survey Program 

CDFO Canadian Department of Fisheries and Oceans 

CEQ Council on Environmental Quality 

CFR Code of Federal Regulations 

cm centimeter(s) 

cm/s centimeters per second 

CV coefficient of variation 

dB decibel(s) 

dB re 1 μPa rms decibels re 1 microPascal root-mean-square 

dB re 1 μPa at 1 m decibels re 1 microPascal at 1 meter 

DEW Defensive Early Warning (system) 

DMT DeLong Mountain Terminal 

EEZ exclusive economic zone 

EFH essential fish habitat 

ESA Endangered Species Act 

FMP fisheries management plan 

ft feet 

FR Federal Register 

FWS Fish and Wildlife Service 

G&G geophysical and geological (permit) 

gal gallon(s) 

6/m2

 grams per square meter(s) 

Hz Hertz 

IHA Incidental Harassment Authority 

in inch(es) 

in3

 cubic inch(es) 

ITM Information Transfer Meeting 

IWC International Whaling Commission 

kHz kiloHertz 

kW kilowatt(s) 

km kilometer(s) 

kn knot(s) 

L liter(s) 

LME large marine ecosystem 

LOA Letter of Authorization 

m meter(s) 

m/s3

 meters per second 

mi mile(s) 

mi2

 square mile(s) 

 ix
MMC Marine Mammal Commission 

MMPA Marine Mammal Protection Act 

MMS Minerals Management Service 

MOU Memorandum of Understanding 

MSFCM Magnuson-Stevens Fishery Conservation Management Act 

NAAQS National Ambient Air Quality Standards 

NEPA National Environmental Policy Act 

NMFS National Marine Fisheries Service 

nmi nautical mile(s) 

NOAA National Oceanographic and Atmospheric Administration 

NRC National Research Council 

NRDC National Resource Defense Council 

NSB North Slope Borough 

OBC ocean-bottom cable (surveys) 

OCS outer continental shelf 

PEA Programmatic Environmental Assessment 

ppb parts per billion 

P.L. Public Law 

ppm parts per million 

PSD Prevention of Significant Deterioration 

psi pounds per square inch 

PTE potential to emit 

rms root-mean-square 

ROI rate of increase 

RS/FO Regional Supervisor/Field Operations 

RUSCALA Russian-American Long-Term Census of the Arctic 

TAPS Trans-Alaska Pipeline System 

U.S.C. United States Code 

USDOC U.S. Department of Commerce 

USDOD U.S. Department of Defense 

USDOI U.S. Department of the Interior 

USEPA U.S. Environmental Protection Agency 

yd yard(s) 

Y-K Delta Yukon-Kuskokwim Delta 

2D two-dimensional (seismic surveys) 

3D three-dimensional (seismic surveys) 

< less than 

> greater than 

% percent 

~ about 

+ plus/minus 

μg/L micrograms per liter 

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I. INTRODUCTION

The Outer Continental Shelf Lands Act (OCS Lands Act), as amended, mandates the Secretary of the 

Interior through the Minerals Management Service (MMS), to manage the development of the outer 

continental shelf (OCS) oil, gas, and mineral resources while protecting the human, marine, and coastal 

environments (43 U.S.C. 1340). Pursuant to the National Environmental Policy Act (NEPA), this 

Programmatic Environmental Assessment (PEA) has been prepared to determine the potential impacts that 

may result from what MMS believes is a foreseeable level of geophysical exploration and scientific 

research in 2006 using seismic surveys (e.g., two-dimensional [2D] and three-dimensional [3D] streamer 

and cable [ocean bottom and vertical] surveys and high-resolution site-clearance surveys) to produce data 

and information on oil and gas resources in support of possible exploration and development activities in 

the Federal waters of the Chukchi and Beaufort seas (Map 1). 

The PEA supports MMS’ permitting process and regulatory authority for geophysical and scientific 

research seismic surveys. This PEA also provides NEPA documentation for the U.S. Department of 

Commence, National Oceanic and Atmospheric Administration, National Marine Fisheries Service’s 

(NMFS) possible issuance of Incidental Harassment Authorizations (IHA’s) to the seismic-survey industry 

to take marine mammals by harassment, incidental to conducting prelease and ancillary on-lease oil and gas 

seismic surveys in the Beaufort and Chukchi seas (see Sec. I.A.1 Regulatory Framework). To address its 

NEPA responsibilities, NMFS agreed to become a cooperating agency (as that term in defined in 40 CFR 

1501.6) and proposed to adopt this PEA as authorized by 40 CFR 1506.3 as its own NEPA statement. 

This programmatic environmental document addresses a group of similar or related actions as a whole 

(seismic surveys in the Arctic Ocean in 2006) rather than one at a time in a separate environmental 

document, and it is an effective means for addressing broad cumulative issues and impacts. The 

“foreseeable level of activity” is based on MMS discussions with the oil and gas industry, the number of 

active leases in the Beaufort Sea, proposed Chukchi Sea Lease Sale 193, and the evaluation of potential oil 

and gas resources. With the renewed interest in oil and gas exploration on the OCS portions of the Chukchi 

and Beaufort seas and the short open-water season, MMS believes that geophysical seismic surveys will be 

conducted concurrently in the Chukchi Sea and Beaufort Sea OCS Planning Areas in 2006. 

Taking into account all of the factors addressed in the PEA, MMS and NMFS will determine if the 

Proposed Action would significantly affect the quality of the human environment. 

I.A. Background.

I.A.1. Regulatory Framework. Pursuant to 30 CFR 251.4, a Geological and Geophysical (G&G) 

permit must be obtained from MMS to conduct geological or geophysical exploration for oil, gas, and 

sulphur resources. Separate permits must be obtained for either geological or geophysical explorations for 

mineral resources. The G&G activities also can occur without a permit, provided such activities are 

ancillary and conducted pursuant to a lease issued or maintained under the OCS Lands Act. The 2D and 

3D seismic surveys usually occur over unleased OCS lands by potential lessees to collect information in 

preparation for bidding in a lease sale. The upcoming lease sale may be in an area where there are no 

current leases (such as in the Chukchi Sea Planning Area) or where there are both current leases and 

unleased blocks and additional sales are planned (such as in the Beaufort Sea Planning Area). This seismic 

surveying in preparation for an upcoming lease sale often is called “prelease” surveying. 

The 2D/3D surveys also may be proposed over areas of: (1) leased blocks by the lessee or operator to 

gather information to identify the best sites on their leases to consider for exploration/delineation drilling; 

or (2) on- and off-lease to provide seismic-survey information between their leases and other wells, so the 

geologic information from wells can be “extrapolated” to their leases with the seismic-survey information. 

Both types of seismic surveys are considered geophysical-exploration activities and require a geophysicalexploration permit from MMS. 

 PEA-1 
High-resolution seismic surveys (often referred to as postlease, on-lease, or site-clearance surveys) are 

ancillary activities authorized by the lease and are conducted under regulations (30 CFR 250). These 

seismic surveys are done by the lessee or operator on a lease or unit (several leases managed as a group to 

produce common reservoirs) to collect required site-specific information (on potential geohazards or 

sensitive seafloor resources) in support of the preparation of an Exploration Plan or a Development and 

Production Plan. Although MMS requires notification of these activities and the mitigation measures 

imposed by lease stipulations and specified in Notice to Lessees and Operators 00-A01, there are no 

additional applications or approvals necessary. To support the preparation of Right-of-Way Pipeline 

applications, high-resolution surveys are required to be run along proposed pipeline routes (both on lease 

and off lease) to identify potential geohazards and sensitive seafloor resources. 

Under the Marine Mammal Protection Act (MMPA), the taking of marine mammals without a permit or 

exemption from the management agency (NMFS or the U.S. Department of the Interior [USDOI], Fish and 

Wildlife Service [FWS]) is prohibited. Taking means to harass, hunt, capture, or kill; or attempt to harass, 

hunt, capture, or kill, any marine mammal. Because seismic-survey noise has the potential to harass marine 

mammals, an authorization under the MMPA seems warranted. 

The NMFS and FWS are evaluating several industry applications and considering issuing IHA’s and/or 

Letters of Authorization (LOA’s) under section 101(a)(5)(D) of the MMPA for taking marine mammals 

incidental to conducting prelease and ancillary on-lease oil and gas seismic surveys in the Beaufort and 

Chukchi seas. 

The NMFS has defined two types of incidental take on marine mammals: Level A harassment, which is 

likely to cause injury and/or harm, and Level B harassment, which is likely to cause a behavioral response. 

The NMFS’ policy has been to use the 180-decibel (dB) root-mean-squared (rms) isopleth for cetaceans 

and 190-dB rms isopleth for pinnipeds to indicate where Level A harassment from acoustic sources begins. 

The 180-dB rms isopleth is used by FWS to indicate where Level A harassment begins for the Pacific 

walrus. The 160-dB rms isopleth is used by NMFS to indicate where Level B harassment begins for 

acoustic sources, including impulse sounds, such as used for seismic surveying. 

Determinations by NMFS under the MMPA will be made in part on the information and analyses in this 

PEA to ensure that small takings will: (1) have a negligible impact on marine mammal stocks; (2) not have 

an unmitigable adverse impact on subsistence needs for marine mammals; and (3) be at the lowest level 

practicable (through implementation of appropriate mitigation). 

Section 7 (16 U.S.C. 1538) of the Endangered Species Act (ESA) states that all Federal departments and 

agencies shall, in consultation with and with the assistance of the Secretary of the Interior/Commerce 

(Secretary), ensure that any actions authorized, funded, or carried out by them do not jeopardize the 

continued existence of any endangered species or threatened species, or result in the destruction or adverse 

modification of habitat of such species, which is determined by the Secretary to be critical, unless an 

exception has been granted by the Endangered Species Committee. Section 9 (16 U.S.C. 1538) of the ESA 

identifies prohibited acts related to endangered species and prohibits all persons, including all Federal, 

State, and local governments, from taking listed species of fish and wildlife, except as specified under 

provisions for exemptions (16 U.S.C. 1539). A summary of MMS’ ESA consultations with NMFS and 

FWS is provided in Section IV. 

The 1996 reauthorization of the Magnuson-Stevens Fishery Conservation and Management (MSFCM) Act 

amendments require consultation between the Secretary of Commerce and Federal and State agencies on 

activities that may adversely impact essential fish habitat (EFH) for those commercial-fish species managed 

by fish-management plans and managed under the MSFCM Act. A summary of MMS’ EFH consultation 

with NMFS is provided in Section IV. 

I.A.2. Historical Overview. The MMS-permitted seismic surveys have been conducted in the 

Beaufort and Chukchi seas since the late 1960’s/early 1970’s. The vast majority of geophysical seismic 

surveys conducted in the Beaufort and Chukchi seas to date used the less detailed 2D methodology; 

 PEA-2 
whereas 2006 seismic-survey activities likely would use the more informative 3D methodology to explore 

for oil and gas deposits. 

Open-water and over-ice seismic surveys in Beaufort Sea Federal waters began in the late 1960’s and 

peaked in the 1980’s. Subsequent years saw fewer and fewer surveys being conducted. No permits for 

seismic-survey activities have been issued by MMS for the Beaufort Sea since 2004. More than 100,000 

line-miles of 2D and 3D seismic surveys have been collected to date in the Beaufort Sea Planning Area. 

Open-water and over-ice seismic-survey activity in the Federal waters of the Chukchi Sea has been 

significantly less than that in the Beaufort Sea. Few surveys were conducted in the 1970’s; however, in the 

1980’s, seismic-survey activities increased. The last MMS-permitted marine seismic survey in the Chukchi 

Sea occurred in 1990. Approximately 80,000 line-miles of 2D seismic surveys have been collected to date 

in the Chukchi Sea Planning Area. To date, no 3D seismic surveys have been conducted in the Chukchi 

Sea OCS. 

The most G&G permits issued in any one year in the Chukchi Sea was seven (6 marine and 1 over-ice) in 

1986. In the Beaufort Sea, 23 MMS G&G permits were issued in 1982 (11 marine and 12 over-ice 2D 

surveys) and 24 MMS G&G permits were issued in 1983 (1, 3D over-ice survey; 14, 2D over-ice surveys; 

and, 9, 2D marine surveys). 

Section III.C.1 provides more information and discussion about the history of seismic surveys in the 

Beaufort and Chukchi seas. Figures III.C-1, III.C-2, and III.C-3 illustrate cumulatively, the geographic 

extent of OCS-permitted seismic surveys conducted in the Beaufort and Chukchi seas beginning in the 

1970’s and through 2004. 

I.B. Purpose of and Need for the Proposed Action. 

The Proposed Action is for MMS to issue up to four seismic-survey-related geophysical exploration 

permits in both the Chukchi and Beaufort seas during 2006. Geophysical seismic surveys provide 

information that is used by industry and government to make an informed decision, evaluate the potential 

for offshore oil and gas resources, and determine the presence of geologic hazards. Seismic-survey 

information reduces the drilling of unnecessary exploration wells. The MMS has a mandate to ensure that 

the seismic-survey data and information collected by industry and government are obtained in a technically 

safe and environmentally sound manner. The MMS regulations (30 CFR 251) state that geological and 

geophysical activities cannot: 

• interfere with or endanger operations under any lease or right-of-way easement, right-of-use, 

scientific notice, or permit issued or maintained pursuant to the OCS Lands Act; 

• cause harm or damage to aquatic life, property, or to the marine, coastal, or human environments; 

• cause pollution; 

• create hazardous or unsafe conditions; 

• unreasonably interfere with or harm other uses of the area; 

• disturb archaeological resources; or 

• cause hazardous or unsafe conditions. 

The MMS needs geological and geophysical seismic-survey information to fulfill its statutory 

responsibilities to ensure safe operations, support environmental impact analyses, protect benthic resources 

through avoidance measures, ensure fair market value for leases, make royalty-relief determinations, 

conserve oil and gas resources, and perform other statutory responsibilities. When MMS reviews the 

acquired seismic-survey information and determines that resources of concern (e.g., archaeological or 

sensitive benthic resources) could be adversely affected, the operators/lessees are required to proceed in 

one of the following three ways: 

 PEA-3 
1. employ specific operational procedures to protect the resources of concern; 

2. adjust the location of the proposed activity(ies) to a distance necessary to prevent disturbance of 

the resource(s) of concern; or 

3. perform additional investigations to establish that the potential resources of concern do not exist at 

the proposed site or will not be adversely affected by the proposed activity. 

The MMS must comply with various environmental laws such as the ESA, the MMPA, and the MSFCM 

Act. Therefore, MMS is using the information in the PEA to support ESA Section 7 consultations with 

NMFS and the FWS in the Chukchi and Beaufort seas. The NMFS also will use this PEA to support 

authorizations of incidental take under Section 101(a)(5) of the MMPA. The FWS prepared their own 

NEPA documentation to support their own authorizations of incidental take under Section 101(a)(5) of the 

MMPA. The PEA also supports MMS and NMFS consultation on EFH as required by the MSFCM Act. 

I.C. Scope, Objectives, and Assumptions. 

The scope of MMS’ action is to continue permitting geophysical and scientific research seismic surveys 

that will provide the oil and gas industry and MMS with accurate data on the location, extent, and 

properties of hydrocarbon resources, as well as information on shallow geological hazards and seafloor 

geotechnical properties. The PEA’s objectives are to: 

1. Provide a broadly scoped programmatic NEPA document that environmentally assesses what 

MMS believes to be a foreseeable level of geophysical and scientific research and seismic-survey 

activity in 2006 in Federal waters of the Beaufort and Chukchi seas, from which other NEPA 

documents that evaluate more specific marine seismic-survey plans can be tiered. 

2. Provide environmental information that can be used by NMFS to evaluate several industry 

applications for IHA’s, under Section 101(a)(5)(D) of the MMPA, for taking marine mammals 

incidental to conducting prelease and ancillary oil and gas seismic surveys in the Beaufort and 

Chukchi seas. 

3. Characterize OCS seismic activities that available information indicates are likely to occur in the 

Chukchi and Beaufort seas. 

4. Determine whether any significant adverse impacts might occur from such activities. 

5. Evaluate the Proposed Action alternatives, including the mitigation measures, which are designed 

to help prevent any potential significant adverse impacts. 

6. Determine if a Finding of No Significant Impact is applicable, or whether an environmental 

impact statement would need to be prepared for the Proposed Action. 

The MMS assumes in this PEA that up to eight marine seismic surveys (4 each in the Chukchi and Beaufort 

seas) are likely to occur in 2006 in the Arctic Ocean. The MMS also assumes that marine resources could 

be exposed to accidentally spilled lubricating oil or diesel fuel from a vessel associated with seismic-survey 

operations. A torn or damaged streamer also might leak into the marine environment. The liquid used to 

fill and provide streamer buoyancy usually is liquid paraffin that is biodegradable and evaporates very 

quickly. Solid/gel streamers, which will not leak if damaged, also are available for use. 

Eight refueling operations (1 per marine seismic-survey operation) are expected to occur during the 2006 

seismic-survey season. The MMS believes that the incidents involving the release of oil and fuel from 

vessels during refueling likely would be small, on the order of less than 5 gallons (gal) per refueling 

event—in total, approximately 40 gal (20 gal in the Chukchi Sea and 20 gal in the Beaufort Sea) of fuel 

might be spilled during the 2006 seismic-survey season. Refueling operations in the Beaufort Sea likely 

would occur at Prudhoe Bay’s West Dock facility, and refueling operations in the Chukchi Sea likely 

would occur at sea (in State and/or Federal waters) with the use of fuel supply vessels. 

In addition, MMS believes the risk of fuel spills resulting from vessels colliding with each other or with ice 

is low because: (1) seismic-survey operations must maintain a distance (usually about 15 miles [mi]) from 

each other to ensure not interfering with each others’ data collection; and (2) seismic surveys would be 

conducted in open water only, as the presence of ice interferes with vessel maneuverability and acoustic 

 PEA-4 
equipment. Table I.C-1 summarizes other assumptions used to identify and analyze the impacts associated 

with conducting seismic surveys in the Chukchi and Beaufort seas in 2006. 

This PEA does not environmentally assess, as part of its Proposed Action, potential oil and gas activities 

(exploration drilling, etc.) in Federal waters that already have been evaluated in Beaufort Sea sale-related 

environmental assessment documents or that will be evaluated in the Chukchi Sea Lease Sale 193 

Environmental Impact Statement. The PEA’s cumulative activities scenario (Sec. III.C) and cumulative 

impact analysis (Sec. III.H) focus on oil- and gas-related and non-oil- and gas-related noise-generating 

events/activities in both Federal and State of Alaska (within 3 mi of shore) waters that are likely and 

foreseeable during the period of the Proposed Action. Contributions from community and commercial 

development, military activities, and arctic warming also are considered. 

Although not required by the MMPA if marine mammals are not being taken, NMFS, MMS, and FWS 

believe an incidental take authorization (ITA) under the MMPA seems warranted from the FWS (for the 

Pacific walrus and polar bears) and NMFS (for cetaceans and pinnipeds other than the Pacific walrus), 

because seismic-survey noises have the potential to harass marine mammals. Also, NMFS has stated that it 

cannot complete an Incidental Take Statement under the ESA in regard to harassment of endangered 

species (e.g., bowhead, fin, and humpback whales) before appropriate MMPA incidental take is authorized. 

Because an Incidental Take Statement is issued under the ESA to MMS once the requirements of Section 

101(a)(5) of the MMPA have been met, any seismic-survey permits to be issued by the MMS Alaska OCS 

Region will state that seismic surveys shall not commence until such time that FWS and NMFS issue 

MMPA ITA’s. 

In addition, each G&G permit application will receive an additional review to determine if the proposed 

seismic survey is within the scope of the activities addressed and environmentally evaluated in this PEA. 

Those seismic surveys within the scope of the activities addressed and environmentally evaluated in this 

PEA will be permitted, and those that do not will receive further NEPA analysis before possibly being 

permitted. Further analysis also will be conducted, if the number of seismic-survey-permit applications 

exceeds the number of seismic surveys in the Proposed Action evaluated in this PEA. 

I.D. Issues and Concerns.

Issues and concerns associated with seismic-survey operations in the marine environment have been 

documented by the scientific community, in government publications, and at scientific symposia. In 

addition, public testimony and traditional knowledge from Alaskan Natives have provided valuable 

information about seismic-survey operations. 

Based on the information obtained from the aforementioned sources, the following more prominent issues 

and concerns have been identified by MMS and NMFS: 

• Protection of subsistence resources and the Inupiat culture and way of life. 

• Risks of oil spills and their potential impacts on area fish and wildlife resources. 

• Disturbance to bowhead whale-migration patterns. 

• Impacts of seismic operations on marine fish reproduction, growth, and development. 

• Harassment and potential harm of wildlife, including marine mammals and marine birds, by 

vessels operations and movements. 

• Impacts on water and air quality. 

• Changes in the socioeconomic environment. 

• Impacts to threatened and endangered species. 

• Impacts to marine mammals. 

• Incorporation of traditional knowledge in the decisionmaking process. 

• Effectiveness of marine mammal monitoring and other mitigation and monitoring measures. 

 PEA-5 
In accordance with Council on Environmental Quality guidelines, the PEA will focus on those activities 

and resources for which the potential for significant impacts exists and identifying mitigation measures to 

avoid and/or minimize those impacts. 

I.E. Overview of Seismic Surveys.

I.E.1. Marine-Streamer 3D and 2D Surveys. Airguns are the acoustic source for 2D and 3D 

seismic surveys. Their individual size can range from tens to several hundred cubic inches (in3

). A 

combination of airguns is called an array, and operators vary the source-array size during the seismic 

survey to optimize the resolution of the geophysical data collected. Airgun array sizes for 2D/3D seismic 

surveys are expected to range from 1,800-4,000 in3

 but may range up to 6,000 in3. These arrays emit 

pulsed rather than continuous sounds. While most of the energy is directed downward and the short 

duration of each pulse limits the total energy, the sound can propagate horizontally for several kilometers 

(Greene and Richardson, 1988; Hall et al., 1994). 

Marine-streamer 3D seismic surveys vary markedly depending on client specifications, subsurface geology, 

water depth, and geological target reservoir. Figure I.E-1 illustrates a typical marine seismic survey using 

streamers. The vessels conducting these surveys generally are 70-90 meters (m) long. A 3D source array 

typically consists of two to three subarrays of six to nine airguns each, and is about 12.5-18 m long and 16-

36 m wide. Vessels tow one to three source arrays, depending on the technical survey-design specifications 

required for the geologic target, to generate the acoustic energy. Most operations use a single-source 

vessel; however, in a few instances, more than one source vessel will be used. The overall energy output 

for the permitted activity will be the same, but the firing of the source arrays on the individual vessels will 

be alternated. The sound-source level (zero-to-peak) associated with 3D seismic surveys ranges between 

233 and 240 decibels re 1 microPascal at 1 meter (dB re 1 μPa at 1 m). The arrays usually are aligned 

parallel with one another and towed 50-200 m behind the vessel. Following behind the source arrays by 

another 100-200 m are multiple (4-12) streamer-receiver cables, and each streamer can be 3-8 kilometers 

(km) long and spread out over a width of 400-900 m. Streamers are passive listening equipment consisting 

of multiple hydrophone elements. 

Vessel transit speeds are highly variable, ranging from 8-20 knots (kn) depending on a number of factors 

including, but not limited to, the vessel itself, sea state, urgency (the need to run at top speed versus normal 

cruising speed), and ice conditions. Marine 3D surveys are acquired at typical vessel speeds of 4.5 kn (8.3 

km/hour). A source array is activated approximately every 10-15 seconds, depending on vessel speed. The 

timing between activations varies between surveys to achieve the desired spacing required to meet the 

geological objectives of the survey; typical spacing is either 25 or 37.5 m. Depending on the shotpoint 

interval, airguns are fired between 20 and 70 times per mile. 

The 3D-survey data are acquired on a line-by-line basis, whereby the vessel continues down a track-line to 

provide adequate subsurface coverage from the beginning of the survey boundary. Acquiring a single track 

line may take several hours, depending on the size of the survey area. The vessel then takes 2-3 hours to 

turn around at the end of the track line and starts acquiring data along the next track line. Seismic vessels 

operate day and night and a survey may continue for days, weeks, or months, depending on the size of the 

survey, data-acquisition capabilities of the vessel, and weather conditions. It should be noted, however, 

that data are not being acquired continuously, as streamer and source deployment, in-sea equipment 

maintenance, and other operations also add to the survey time. “On a very good survey we may be in 

shooting mode up to 40% of the time we are on site. Typically our shooting times average between 25% to 

35%” (Fontana, 2003, pers. commun.). 

Adjacent transit lines for a modern 3D survey generally are spaced several hundred meters apart and are 

parallel to each other across the survey area. Modern marine-seismic vessels tow up to 16 streamers with 

an equipment-tow width of up to approximately 1,500 m between outermost streamers. Biodegradable 

liquid paraffin is used to fill the streamer and provide buoyancy. Solid/gel streams also are available for 

use. The areal extent of this equipment limits both the turning speed and the area a vessel covers. It is, 

 PEA-6 
therefore, common practice to acquire data using an offset racetrack pattern, whereby the next acquisition 

line is several kilometers away from and traversed in the opposite direction of the track line just completed. 

Marine-streamer 2D surveys use similar geophysical-survey techniques as 3D surveys, but both the mode 

of operation and general vessel type used are very different from those used in modern 3D marine surveys. 

The 2D surveys are designed to provide a less-detailed, coarser sampled subsurface image compared to 3D 

surveys, and they are conducted over wide areas or on a regional basis to identify potential prospective 

areas. 

The 2D seismic-survey vessels generally are smaller than modern 3D-survey vessels, although larger 3Dsurvey vessels are able to conduct 2D surveys. The source array typically consists of three or more 

subarrays of 6-8 airgun sources each, and it is about 12.5-18 m long and 16-36 m wide. The sound-source 

level (zero-to-peak) associated with a 2D marine seismic survey is the same as 3D marine seismic surveys 

(233-240 dB re 1 μPa at 1 m). Following behind the source arrays is a single hydrophone streamer 

approximately 8-12 km long, depending on the geophysical objectives of the survey. 

The 2D surveys acquire data along single track lines that are spread widely apart compared to 3D surveys, 

which acquire data in a closely packed rectangular area. Therefore, considerably less source effort (less 

acoustic energy) is required to cover a given area of the subsurface compared to 3D surveys. 

Marine seismic vessels are designed to operate for several months without refueling or replenishments. A 

guard or chase boat probably would be used for safety considerations, general support, maintenance, and 

resupply of the main vessel, but it would not be directly involved with the collection of seismic data. 

Helicopters also may be used, when available, for vessel support and crew changes. 

Marine-streamer 2D and 3D surveys in the Beaufort and Chukchi seas require an essentially ice-free 

operational environment because of having to maneuver the long streamers and airgun arrays. Thus, the 

timing and areas of the surveys will be dictated by ice conditions. The data-acquisition season in the 

Chukchi Sea could start as soon as ice conditions permit (sometime in June), and end when ice conditions 

prevent further operations to be conducted (sometime in early November). The Beaufort Sea dataacquisition season, because of a later ice-free season, likely would begin in late July/early August and end 

in early October. Even during this time period, there is no assurance that any given location will be ice 

free. The Beaufort Sea season is additionally constrained by the need to get the vessel out of the area 

before ice conditions trap the vessel in the area. 

I.E.2. Ocean-Bottom-Cable Seismic Surveys. Ocean-bottom-cable (OBC) seismic surveys are 

used in Alaska primarily to acquire seismic data in water that is too shallow for the data to be acquired 

using a marine-streamer vessel and too deep to have static ice in the winter. The seismic survey requires 

the use of multiple vessels (usually two vessels for cable layout/pickup, one vessel for recording, one vessel 

for shooting, and may include one or two smaller utility boats). Most operations use a single source vessel. 

In a few instances, however, more than one source vessel will be used. The overall energy output for the 

permitted activity will be the same, but the firing of the source arrays on the individual vessels will be 

alternated. These vessels generally, but not necessarily, are smaller than those used in streamer operations, 

and the utility boats can be very small, in the range of 10-15 m. 

An OBC operation begins by laying cables off the back of the layout boat. Cable length typically is 4-6 km 

but can be up to 12 km. Groups of seismic-survey receivers (usually a combination of both hydrophones 

and vertical-motion geophones) are attached to the cable in intervals of 12-50 m. Multiple cables are laid 

on the seafloor parallel to each other using this layout method, with a cable spacing of between hundreds of 

meters to several kilometers, depending on the geophysical objective of the seismic survey. When the 

cable is in place, a vessel towing the source array passes over the cables with the source being activated 

every 25 m. The source array may be a single or dual array of multiple airguns, which is similar to the 3D 

marine seismic survey. The sound-source level (zero-to-peak) associated with an OBC seismic survey is 

the same as the 2D and 3D marine seismic surveys (233-240 dB re 1 μPa at 1 m). Sometimes a faster 

source-ship speed of 6 kn instead of the normal 4.5-kn speed is used with a decrease in the time the source 

is being activated. 

 PEA-7 
After a source line is acquired, the source ship takes about 10-15 minutes to turn around and pass over the 

next cable. When a cable is no longer needed to record seismic-survey data, it is recovered by the cablepickup ship and moved to the next recording position. A particular cable can lay on the seafloor anywhere 

from 2 hours to several days, depending on operation conditions. Normally, a cable is left in place for 

about 24 hours. 

An OBC seismic survey typically covers a smaller area (approximately 10 by 20 mi) and may spend days 

in an area. In contrast, 3D streamer seismic surveys cover a much larger area (thousands of square miles) 

and only stay in a particular area for hours. 

While OBC seismic surveys might occur in the Beaufort Sea, they are not anticipated to occur in the 

Chukchi OCS because of its greater water depths and the greater efficiency of streamer operations in deep 

water. Recent technological developments have been introduced that provide improved operational 

flexibility for equipment deployment, recovery, and data collection in the field, but the costs are high 

compared to streamer-collected data. 

I.E.3. High-Resolution Site-Clearance Surveys. A high-resolution seismic survey is the 

preferred method used by the oil and gas industry to provide required information to MMS about the site of 

proposed exploration and development plans in OCS leased areas. High-resolution surveys primarily are 

used by the oil and gas industry to locate shallow hazards; obtain engineering data for placement of 

structures (e.g., proposed platform locations and pipeline routes); and detect geohazards, archaeological 

resources, and certain types of benthic communities. 

A typical operation consists of a vessel towing an acoustic source (airgun) about 25 m behind the ship and a 

600-m streamer cable with a tail buoy. The source array usually is a single array composed of one or more 

airguns. A 2D high-resolution site-clearance survey usually has a single airgun, while a 3D high-resolution 

site survey usually has a tri-cluster of airguns. The ships travel at 3-3.5 kn (5.6-6.5 km/hour), and the 

source is activated every 7-8 seconds (or about every 12.5 m). All involved ships are designed to be ultraquiet, as the higher frequencies used in high-resolution work are easily masked by the vessel noise if 

special attention is not paid to keeping the ships quiet. 

Typical surveys cover one block at a time. The MMS regulations require information be gathered on a 

300- by 900-m grid, which amounts to about 129 line-kilometers of data per lease block. If there is a high 

probability of archeological resources, the north-south lines are 50 m apart and the 900 m remains the 

same. Including line turns, the time to survey a lease block is approximately 36 hours. Airgun volumes for 

high-resolution surveys typically are 90-150 in3

, and the output of a 90-in3 airgun ranges from 229-233 dB 

re 1μPa at 1 m. Airgun pressures typically are 2,000 psi (pounds per square inch), although they can be 

used at 3,000 psi for more output. 

In 2006, MMS does not anticipate any on-lease high-resolution surveys being conducted in the Chukchi 

Sea, because there are no active leases. High-resolution surveys are expected to occur in 2006 in the 

Beaufort Sea, where many lease blocks are owned by the oil and gas industry. 

 PEA-8 
II. DESCRIPTION OF THE ALTERNATIVES 

The Proposed Action is for the Minerals Management Service (MMS) to issue four seismic survey 

geophysical-exploration permits in both the Chukchi and Beaufort seas outer continental shelf (OCS) 

during 2006. The permits would allow the gathering of data needed by industry and government to assess 

hydrocarbon resources and ensure these activities occur in a technically safe and environmentally sound 

manner. Through the scoping process, a range of alternatives has been identified that consider issues of 

concern (see Sec. I.D) and the need to protect the fish and wildlife resources of the Beaufort and Chukchi 

seas and associated subsistence-harvest activities. 

II.A. Range of Alternatives.

The alternatives that follow were developed taking into consideration the Proposed Action’s purpose and 

need, as described in Section I (Introduction) and the potential impacts identified through the scoping 

process. The primary impacts of the Proposed Action are associated with the generation of high-energy 

acoustic sounds from seismic-survey operations, seismic-vessel movements and traffic, air traffic 

associated with supporting seismic-survey operations, and cumulative impacts. The sound generated by a 

seismic-survey operation and its overall operation potentially could adversely affect a variety of fish and 

wildlife resources, including whales and seals, if not properly mitigated. The endangered bowhead whale, 

particularly females and calves, are especially vulnerable to the harassing sounds of seismic surveys. In 

addition, seismic-survey operations have the potential to adversely affect marine mammal subsistenceharvest activities, if seismic-survey operations are not first coordinated with the subsistence-harvest 

community(ies). Although not adversely affected by the sounds generated by seismic surveys, marine birds 

are susceptible to colliding with vessels that are brightly lighted, especially during bad weather conditions. 

A more thorough discussion of the aforementioned and additional potential impacts is included in Section 

III (Affected Environment and Impact Analysis). The mitigation measures that MMS will include as 

stipulations in its Beaufort and Chukchi seas Geological and Geophysical (G&G) seismic-survey permits 

will prevent the Proposed Action from having a significant impact (and further reduce adverse impacts) on 

the fish and wildlife resources of the Beaufort and Chukchi seas and the subsistence-harvest activities that 

rely on them (see Sec. IV - Summary of Findings, Mitigation Measures, and Recommendations). 

Alternative 1. No seismic-survey permits issued for geophysical exploration activities (No 

Action). 

Alternative 2. Seismic surveys for geophysical-exploration activities would be permitted with 

existing Alaska OCS G&G exploration stipulations and guidelines. 

The following four alternatives emphasize including a specified exclusion (safety) zone for marine 

mammals, in addition to complying with existing G&G exploration stipulations and guidelines. 

Furthermore, after each alternative is environmentally assessed (Sec. III - Existing Environment and Impact 

Assessment) additional protective measures for fish, wildlife, and subsistence-harvest resources might be 

identified (Sec. IV - Summary of Findings, Mitigation Measures, and Recommendations) and incorporated 

as permit stipulations. All alternatives require the seismic-survey operator to successfully perform and 

demonstrate the efficacy of mitigation measures and have the incidental taking of marine mammals 

authorized under the Marine Mammal Protection Act (MMPA). 

Alternative 3. Seismic surveys for geophysical exploration activities would be permitted 

incorporating existing Alaska OCS G&G exploration stipulations and guidelines and additional 

protective measures for marine mammals, including a 120-decibel-(dB)-specified exclusion zone. 

Alternative 4. Seismic surveys for geophysical-exploration activities would be permitted 

incorporating existing Alaska OCS G&G exploration stipulations and guidelines and additional 

protective measures for marine mammals, including a 160-dB-specified exclusion zone.

 PEA-9 
Alternative 5. Seismic surveys for geophysical-exploration activities would be permitted 

incorporating existing Alaska OCS G&G exploration stipulations and guidelines and additional 

protective measures for marine mammals, including 160-dB- and 120-dB-specified exclusion 

zones. 

Alternative 6. Seismic surveys for geophysical-exploration activities would be permitted 

incorporating existing Alaska OCS G&G exploration stipulations and guidelines and additional 

protective measures for marine mammals, including a 180/190-dB-specified exclusion zone.

II.A.1. Alternative 1. No Seismic-Survey Permits Issued for Geophysical 

Exploration Activities (No Action). The MMS would not approve seismic-survey permit 

applications for the purpose of obtaining geophysical information about the location, extent, and properties 

of hydrocarbon resources in the Chukchi and Beaufort seas. Industry would have to rely on other measures 

to obtain needed geophysical information, such as using new data-processing technology to reanalyze 

existing geophysical exploration seismic data and/or using survey techniques other than seismic. The 

environmental assessment of alternative geophysical-survey techniques is not part of this programmatic 

environmental assessment (PEA). 

II.A.2. Alternative 2. Seismic Surveys for Geophysical-Exploration Activities would 

be Permitted with Existing Alaska OCS Geological and Geophysical Exploration 

Stipulations and Guidelines. The MMS-implemented regulations specify geophysical operations 

shall be conducted in a manner to ensure that they will not cause pollution, cause undue harm to aquatic 

life, create hazardous or unsafe conditions, or unreasonably interfere with other uses of the area. 

The MMS would approve seismic surveys with stipulations (Appendix A) related to G&G exploration 

activities on the OCS. The stipulations also notify the permittee that operations under the permit are 

subject to the MMPA and the Endangered Species Act, and advise the permittee to contact National Marine 

Fisheries Service (NMFS) and/or Fish and Wildlife Service (FWS) and discuss their proposed activities. 

II.A.3. Alternative 3. Seismic Surveys for Geophysical-Exploration Activities would 

be Permitted with Existing Alaska OCS Geological and Geophysical Exploration 

Stipulations and Guidelines and Additional Protective Measures for Marine 

Mammals, including a 120-dB Specified-Exclusion Zone. The MMS would permit seismic 

surveys in the Beaufort and Chukchi seas, incorporate standard G&G stipulations (Appendix A), and 

require additional protective measures for marine mammals. 

If a seismic-survey operator had not received an incidental take authorization (ITA) from NMFS, this 

alternative would avoid Level A (injury/harm) and Level B (behavior harassment) incidental takes of all 

marine mammals and extend the level of protection to avoid potential disturbances of bowhead whale 

cow/calf pairs and aggregations of bowhead whales and gray whales that could occur due to their 

avoidance of the active seismic vessel. The 120-dB isopleth-exclusion zone would provide such protection. 

The 120-dB isopleth is the approximate zone where Richardson et al. (1999) found at 20 kilometers (km) 

almost total bowhead whale exclusion. Sound levels received by bowhead whales at 20 km ranged from 

117-135 dB re 1 μPascal root-mean-square (dB re 1μPa rms) and 107-126 dB re1μPa rms at 30 km, and it 

is the level recommended by the 2001 Open Water Meeting participants as where significant responses by 

bowhead whales in the Beaufort Sea occur. 

Seismic operations must comply with Alaska OCS Region standard seismic-survey G&G stipulations 

(Appendix A), including: 

• Operators must maintain a minimum spacing of 15 miles between the seismic-source vessels for 

separate operations. The MMS must be notified by means of the weekly report whenever a shut 

down of operations occurs in order to maintain this minimum distance. 

 PEA-10 
The following additional protective measures for marine mammals are based on: (1) the measures in the 

July 1999 and August 2001 IHA’s from NMFS for marine geophysical permits in the Beaufort Sea OCS; 

(2) the protective measures in MMS’ most recent marine seismic-survey exploration permits; (3) Arctic 

Open Water meetings in 1999 and 2001; and (4) the MMS’ Biological Evaluation, dated March 3, 2006 

(USDOI, MMS, 2006), which includes the Proposed Action. 

Exclusion Zone – An exclusion zone from the seismic-survey sound source shall be free of marine 

mammals before the survey can begin and must remain free of marine mammals during the survey. The 

purpose of the exclusion zone is to protect marine mammals from Level A harassment (injury). 

Monitoring of the Exclusion Zone – Individuals (marine mammal biologists or trained observers) shall 

monitor the area around the survey for the presence of marine mammals to maintain a marine mammal-free 

exclusion zone and monitor for avoidance or take behaviors. Visual observers monitor the exclusion zone 

to ensure that marine mammals do not enter the exclusion zone for at least 30 minutes prior to ramp up, 

during the conduct of the survey, or before resuming seismic-survey work after shut down. The NMFS will 

set specific requirements for the monitoring programs and observers. 

Shut Down – The survey shall be suspended until the exclusion zone is free of marine mammals. All 

observers shall have the authority to, and will, instruct the vessel operators to immediately stop or deenergize the airgun array whenever a marine mammal is seen within the exclusion zone. If the airgun array 

is completely powered down for any reason during nighttime or poor sighting conditions, it shall not be reenergized until daylight or whenever sighting conditions allow for the exclusion zone to be effectively 

monitored from the source vessel and/or through other passive acoustic, aerial, or vessel-based monitoring. 

Ramp Up – Ramp up is the gradual introduction of sound to deter marine mammals from potentially 

damaging sound intensities and from approaching the exclusion zone. This technique involves the gradual 

increase (usually 5-6 dB per 5-minute increment) in emitted sound levels, beginning with firing a single 

airgun and gradually adding airguns over a period of at least 20-40 minutes, until the desired operating 

level of the full array is obtained. Ramp-up procedures may begin after observers ensure the absence of 

marine mammals for at least 30 minutes. Ramp-up procedures shall not be initiated at night or when 

monitoring the exclusion zone is not possible. A single airgun operating at a minimum source level can be 

maintained for routine activities, such as making a turn between line transects, for maintenance needs or 

during periods of impaired visibility (e.g., darkness, fog, high sea states), and does not require a 30-minute 

clearance of the exclusion zone before the airgun array is again ramped up to full output. 

Field Verification – Before conducting the survey, the operator shall verify the radii of the exclusion zones 

within real-time conditions in the field. This provides for more accurate exclusion-zone radii rather than 

relying on modeling techniques before entering the field. Field-verification techniques must be consistent 

with NMFS-approved guidelines and procedures. When moving a seismic-survey operation into a new 

area, the operator shall verify the new radii of the exclusion zones by applying a sound-propagation series. 

Monitoring of the Seismic-Survey Area – Aerial-monitoring surveys or an equivalent monitoring 

program acceptable to the NMFS may be required. 

Reporting Requirements – Reporting requirements, such as the monitoring plans required by FWS for 

polar bears and walruses prior to the start of seismic activities, provide the regulating agencies with specific 

information on the monitoring techniques to be implemented and how any observed impacts to marine 

mammals will be recorded. In addition, operators must report immediately any shut downs due to a marine 

mammal entering the exclusion zones and provide the regulating agencies with information on the 

frequency of occurrence and the types and behaviors of marine mammals (if possible to ascertain) entering 

the exclusion zones. 

Temporal/Spatial/Operational Restrictions – Dynamic management approaches to avoid or minimize 

exposure, such as temporal or spatial limitations are based on marine mammals being present in a particular 

place or time, or being engaged in a particularly sensitive behavior (such as feeding). 

 PEA-11 
• Seismic survey must not occur in the Chukchi Sea spring lead system before July 1, unless 

authorized by NMFS, to provide bowhead cow/calf pairs additional protection. 

• Seismic-survey activities are not permitted within the Ledyard Bay spectacled eider critical-habitat 

area. 

• Seismic-survey support aircraft must avoid overflights of Ledyard Bay critical-habitat area after 

July 1; unless aircraft are at an altitude in excess of 1,500 feet or human safety requires deviation 

(e.g., a medical emergency). 

Resource-specific measures to further reduce the potential to cause adverse impacts will be identified 

during the impact-analysis step of the PEA. Depending on the scope of seismic-survey activities, these 

measures could be adopted as requirements for seismic-survey-related G&G permits. Additional mitigation 

measures also may be required by the required MMPA authorizations from NMFS and FWS. 

An inability to effectively perform any mitigation measure will result in MMS suspending the seismicsurvey operator’s permit until such time that the protective measures can be successfully performed and 

demonstrated. For reasons of practicality, an MMPA authorization may not impose all of the mitigation 

measures stated here. Alternatively, an MMPA authorization may specify alternative or additional 

mitigation or monitoring measures (aerial surveys, passive monitoring, time/area closures) to ensure that 

impacts on marine mammals and subsistence needs are at the lowest level practicable. 

II.A.4. Alternative 4. Seismic Surveys for Geophysical-Exploration Activities would 

be Permitted with Existing Alaska OCS Geological and Geophysical Exploration 

Stipulations and Guidelines and Additional Protective Measures for Marine 

Mammals, including a 160-dB Specified-Exclusion Zone. This alternative is identical to 

Alternative 3, except this alternative specifies a 160-dB isopleth-exclusion zone instead of a 120-dB zone. 

The intent is to help protect marine mammals (including bowhead whales) against potential Level B 

(behavior harassment) incidental takes and potential Level A (harassment - injury) incidental takes if the 

seismic operator had not received incidental take authorization from the NMFS and/or FWS. The 160-dB 

isopleth is where Malme et al. (1983, 1984) found migrating gray whales avoided seismic noise along the 

California coast, and it is used by NMFS to indicate where Level B harassment begins for impulse sounds, 

such as seismic. 

II.A.5. Alternative 5. Seismic Surveys for Geophysical-Exploration Activities would 

be Permitted with Existing Alaska OCS Geological and Geophysical Exploration 

Stipulations and Guidelines and Additional Protective Measures for Marine 

Mammals, Including 160-dB and 120-dB Specified-Exclusion Zones. The intent of this 

alternative is the same as Alternatives 3 and 4, except that it provides special protection for: (1) bowhead 

whale calves; (2) reproductive-aged female bowhead whales; (3) aggregations of whales; and (4) fall 

subsistence hunting of bowhead whales in the Beaufort Sea. The NMFS would determine if and when to 

expand the exclusion-zone isopleth from 160 dB to 120 dB, thereby increasing the size of the exclusion 

zone. The criteria used by NMFS for making this decision would be based on the presence of cow/calf 

pairs, aggregations of bowhead whales, and the timing and location of the subsistence hunt in both the 

Beaufort and Chukchi seas. Aerial or vessel-based surveys would reduce the uncertainty about how many 

and what type of bowhead whales (and other marine mammals) might be present. See Section III.F.3 

(Threatened and Endangered Marine Mammals) for a more thorough discussion about how information 

would be gathered and reported and how decisions will be made about when to expand the exclusion-zone 

isopleth from 160 dB to 120 dB. 

 PEA-12 
II.A.6. Alternative 6. Seismic Surveys for Geophysical-Exploration Activities would 

be Permitted with Existing Alaska OCS Geological and Geophysical Exploration 

Stipulations and Guidelines and Additional Protective Measures for Marine 

Mammals, Including a 180/190 dB Specified-Exclusion Zone. This alternative is identical 

to Alternatives 3, 4, and 5, except that it establishes exclusion zone isopleths of 180 dB (Level A 

harassment-injury) for cetaceans and the Pacific walrus and 190 dB (Level A harassment-injury for 

pinnipeds other than the Pacific walrus). The 180-dB and 190-dB isopleths evolved when two expert 

panels (HESS, 1998; NMFS, 1999) determined that at an unknown higher sound pressure level (SPL) level, 

cetaceans and pinnipeds, respectively, potentially could incur permanent hearing impairment (Level A 

harassment). These levels are used by NMFS to indicate where Level A harassment (injury) potentially 

begins. 

II.B. Evaluation of Alternatives. For an alternative to be considered further in this PEA, it 

must adequately support the PEA’s purpose and need as previously identified and discussed in Section I 

(Introduction) and be feasible, that is, be effective (the extent to which the alternative contributes to 

achieving the project objectives); efficient (the extent to which an alternative is a cost-effective means of 

achieving the objectives, consistent with protecting the environment); and acceptable (the extent to which 

the alternative is implementable and acceptable by Federal, State and local entities and in terms of 

applicable laws, regulations and public policies). Implementable means is it feasible in the technical 

(logistical or engineering limitations), environmental, economic, and social senses. 

II.B.1. Alternatives Excluded from Further Evaluation. Alternative 2 (seismic surveys for 

geophysical exploration activities would be permitted with existing Alaska OCS G&G exploration 

stipulations and guidelines) is not considered further, because it is not feasible. This alternative does not 

consider incorporating additional cost-effective protective measures nor does it adequately address social 

issues related to subsistence-harvest activities. 

II.B.2. Alternatives Considered in More Detail. Alternative 1 (No Action - No seismicsurvey permits issued for geophysical exploration activities). This alternative eliminates any potential 

impacts of seismic surveys on the environment, but it does not provide the means for the oil and gas 

industry to effectively obtain the information it needs to evaluate the location, extent, and properties of 

hydrocarbon resources in the Chukchi and Beaufort seas. Without the geophysical data, MMS is hampered 

in its ability to ensure fair market value for leases, make royalty-relief determinations, conserve oil and gas 

resources, and perform other statutory responsibilities. The alternative is not efficient, because it does not 

accommodate cost-effective technologies. It is not acceptable because, while being socially and logistically 

feasible, there are engineering, economical, and possibly environmental limitations of alternative sources of 

information. The alternative will be evaluated further, because it is required by the Council of 

Environmental Quality [40 CFR Ch. V, §1502.14 (d)] and will provide a benchmark for decisionmakers to 

compare the magnitude of environmental effects of the Proposed Action. 

Alternatives 3, 4, 5, and 6 are considered in more detail in the PEA because each, to varying degrees, is 

effective, efficient, and acceptable and, therefore, feasible. Table II.B.1 and the following supportive text 

provide a comparative ranking and discussion of each alternative, relative to their effectiveness, efficiency, 

and acceptability. 

II.B.2.a. Effectiveness Evaluation. With the exception of Alternative 1 (No Action), the remaining 

alternatives allow the oil and gas industry to obtain the information it needs to evaluate effectively the 

location, extent, and properties of hydrocarbon resources in the Chukchi and Beaufort seas. However, 

alternatives with more mitigation (e.g., Alternatives 3 and 5) likely would require more time and resources 

to collect seismic survey data and to operate. 

Relative to the impacts of acoustic sources, the no-action alternative eliminates any possibility of adverse 

impacts due to seismic-survey operations. The physical environmental impacts associated with other field 

methodologies and techniques the oil and gas industry may or may not use are outside the scope of this 

 PEA-13 
PEA. Obtaining better 3D seismic data now could lessen the number of exploration wells (and associated 

environmental impacts) needed in the future. 

The remaining alternatives (3 through 6) are environmentally sound, as they all contain protective measures 

to mitigate possible impacts on marine mammals, and through the National Environmental Policy Act 

(NEPA) process, could contain additional mitigation measures to further protect other fish, wildlife, and 

subsistence-harvest resources from being adversely impacted. Theoretically, alternatives with larger 

exclusion zones would provide greater levels of protection for marine mammals from potential harm and 

harassment; however, the more complicated marine mammal-monitoring requirements associated with 

larger exclusion zones would make it more difficult to collect seismic data. In some instances, some areas 

may not be surveyed due to time constraints; this may cause more seismic surveys to be performed in the 

future. For this reason, Alternative 3 (with its 120-dB isopleth-exclusion zone) is ranked highest for 

environmental soundness but lowest for the efficacy of obtaining data. The remaining three alternatives are 

ranked in descending order, based on the size of the exclusion zone and associated monitoring 

requirements. 

II.B.2.b. Efficiency Evaluation. The most variable cost associated with conducting an environmentally 

sound seismic-survey program in 2006 is associated with monitoring and maintaining the marine mammalexclusion zone. The costs associated with the no-action alternative are related primarily with having to use 

other developing technologies to reanalyze existing seismic data and/or use other field methods to 

physically obtain the information. A cost-benefit analysis of having to implement this alternative, as 

opposed to conducting seismic surveys, has not been made; however, based on MMS professional 

judgment, seismic surveys likely would be determined to be the most cost-effective means to collect highquality geophysical information to assist in determining the locations of potential oil and gas deposits. 

Effectively monitoring larger exclusion zones probably has higher associated costs than effectively 

monitoring smaller exclusion zones because, as the exclusion zone enlarges, more human resources and 

monitoring equipment are necessary. For example, because the outer perimeter of the 120-dB isoplethexclusion zone could range between 20 and 30 km from the sound-source vessel, aircraft and/or other 

acoustic-monitoring equipment would be required to survey and monitor those areas outside the effective 

monitoring range of vessel-based monitors. The costs associated with conducting aerial monitoring and 

marine mammal surveys understandably are higher than conducting vessel-based monitoring. For the 

aforementioned reasons, Alternative 6, with its 180/190-dB isopleth- (smaller) exclusion zone would be 

expected to have the least associated cost. The incremental cost increase to effectively monitor a 160-dB 

isopleth-exclusion zone may not be much more than the cost associated with the 180/190-dB isoplethexclusion zone, unless aerial surveys are required in which case, the costs would substantially rise. 

II.B.2.c. Acceptability Evaluation. Alternatives 1, 3, 4, 5, and 6, and the associated environmental 

protection measures identified in the NEPA process equally comply with applicable State and Federal laws, 

including the ESA and the MMPA, especially because a seismic-survey operator must obtain an IHA for 

marine mammals from the NMFS and FWS before beginning seismic operations. The MMS’ coordination 

with NMFS, a cooperating agency on the PEA, is ongoing. Biological evaluations in support of the ESA 

Section 7 consultations have been submitted to NMFS for the bowhead, fin, and humpback whales and to 

the FWS for spectacled and Steller’s eiders and Kittlitz’s murrelet. Consultation with NMFS regarding the 

potential impacts of the Proposed Action on essential fish habitat is ongoing, and MMS’ evaluation of 

impacts is contained in the PEA. Other applicable Federal laws and Executive Orders (EO’s) the 

alternatives comply with include, for example, the Clean Air Act, Clean Water Act, Coastal Zone 

Management Act, Migratory Bird Treaty Act, NEPA, National Historic Preservation Act, EO 13175 - 

Consultation and Coordination with Indian Tribal Government, and EO 12898 - Environmental Justice in 

Minority and Low-income Populations. 

The most sensitive social issue associated with conducting marine seismic surveys is the potential impact 

on subsistence-harvest activities and the Inupiat lifestyle and culture. Subsistence harvesting bowhead 

whales and other marine mammals is essential to most Inupiat communities on the North Slope. All the 

alternatives to be considered further provide marine mammals some level of protection from potential 

harassment and/or harm. Of course, if no seismic surveys were conducted (the no-action alternative), no 

 PEA-14 
additional impacts to subsistence would occur. However, the no-action alternative does not preclude 

impacts on subsistence from the other field methods (e.g., electromagnetic, aeromagnetic, and gravity 

surveys) that might be used in attempts to collect the desired oil- and gas-resource information. 

Presumably, the seismic-survey alternatives that have larger exclusion zones provide the most protection 

for bowhead whales and other marine mammals. Alternative 3, which theoretically would have the largest 

exclusion zone associated with the 120-dB isopleth, is ranked alongside the no-action alternative as 

potentially having the highest level of subsistence-resource/marine mammal protection. However, because 

bowhead whales apparently show some avoidance in areas of seismic sounds at levels lower than 120 dB 

(Richardson et al., 1999), impacts to subsistence still might occur under all identified alternatives. 

With the exception of the no-action alternative, all the alternatives have environmental protection measures 

that include exclusion zones. While the 120-dB exclusion zone may provide marine mammals with the 

highest level of protection from potential behavioral harassment and injury, it likely is the most expensive 

and difficult to manage because of its anticipated large size and potential use of aerial or vessel-based 

surveys and/or other acoustic monitoring technology. Implementing the smallest exclusion zones 

associated with the 180/190-dB isopleth likely would be more manageable and less costly than the larger 

exclusion zones. Implementing a smaller exclusion zone with no other mitigation measures would not 

completely protect marine mammals from potential Level B behavioral harassment. The feasibility 

(implementable in an environmental sense) of the no-action alternative is uncertain, because which 

alternate field techniques would be used to replace seismic surveys is unknown. No environmental impacts 

in the Chukchi and Beaufort seas are associated with reanalyzing historical seismic data. Barring costs, all 

the alternatives are equally environmentally feasible (that is, achieving some level of marine mammal 

protection from injury and behavioral harassment). If costs become a limiting factor, then the expenses 

associated with conducting aerial or vessel-based surveys and monitoring and other acoustic-monitoring 

technology may make monitoring larger exclusion zones less environmentally feasible. 

There are fewer technical issues and costs associated with effectively monitoring smaller exclusion zones 

than larger exclusion zones. Generally, and with some exceptions due to weather and other disruptive 

oceanic conditions, exclusion zones associated with the 160-dB and 180/190-dB isopleths can be 

effectively monitored with vessel-based monitors. Logistical complications and engineering limitations 

make effective monitoring of the 120-dB isopleth-exclusion zone (in Alternatives 3 and 5) very difficult 

and overall not feasible to accomplish. This is because continuous aerial or vessel-based monitoring, 

possibly with additional acoustic monitoring, would be required to monitor the outer perimeters of the 

exclusion zone that are not accessible to seismic-vessel-based observers. 

Determination of the Selected Alternative will be based on all the factors and issues raised and discussed in 

this section, the detailed analysis of impacts provided in Section III (Existing Environmental and Impact 

Analysis), and comments received during the public review of the PEA. 

 PEA-15 
III. EXISTING ENVIRONMENT AND IMPACT ANALYSIS 

This section presents information about the Arctic Ocean’s biological and physical environment and the 

human activities that depend on the fish and wildlife resources they provide. This section also describes 

and discusses the potential impacts associated with the Proposed Action alternatives. 

III.A. Physical Environment. 

III.A.1. Physical Oceanography. The Chukchi Sea Proposed Action area covers the relatively 

shallow, broad, continental shelf adjacent to the Arctic Ocean. A small portion in the north overlies the 

continental slope and abyssal plain. Water depths range from approximately 10-2,900 meters (m). Two 

shoals, the Hanna and Herald, are within the Chukchi Sea. These shoals rise above the surrounding 

seafloor to approximately 20 m below sea level. There are two major canyons—Herald Canyon and 

Barrow Canyon. The Barrow Sea Valley begins north of Wainwright and trends in a northeasterly 

direction parallel to the Alaskan coast. Herald Valley is to the north. Hope Valley, a broad depression, 

stretches from Bering Strait to Herald Canyon. These topographic features exert a steering effect on the 

circulation patterns in this area. In contrast, the Beaufort shelf is a narrow shelf with no large topographic 

features. Water depths within the Beaufort Sea program area range from 10-200 m. 

The generalized circulation within the Beaufort and Chukchi seas is shown in Figure III.A-1. The 

circulation is influenced primarily by the arctic circulation driven by large-scale atmospheric pressure 

fields. Cyclonic (counterclockwise) winds centered over the central Arctic Ocean predominate, alternating 

with anticyclonic (clockwise) winds for 5- to 7-year periods. In the Beaufort Sea, the large-scale, surfacewater circulation is dominated by the Beaufort Gyre, which moves water to the west in a clockwise motion 

at a mean rate of about 5-10 centimeters per second (cm/s). Below the surface waters, on the shelf edge, 

the Beaufort shelf-break jet moves to the east as a narrow current (Pickart, 2004). Long-term mean speeds 

are about 5-10 cm/s, but daily mean values may be ten times greater. Deeper yet, Atlantic water flows to 

the east as a boundary current in the Arctic. 

On the Beaufort Sea shelf, the currents are determined by the alongshore winds. There are two distinct 

circulation patterns—the open-water season from July to October and the ice-covered season from midOctober to June. During the open-water season, primarily wind-driven currents are energetic, ranging from 

10-100 cm/s. During the ice-covered season, the landfast ice decouples the wind stress from the water, 

resulting in low current speeds. During this season, less than (<) 1% of the currents exceed 20 cm/s 

(Weingartner and Okkonen, 2005). 

In the Chukchi Sea, three branches of North Pacific waters move across the shelf in a northward direction. 

This mean flow is primarily a product of the sea-level slope between the Pacific and the Arctic oceans. The 

first of these currents, the Alaska Coastal Current, flows northeastward along the Chukchi Sea coast of 

Alaska at approximately 4 cm/s (Coachman, 1993; Johnson, 1989; Weingartner et al., 1998). The Alaskan 

coastal water is relatively warm and fresh showing the input from rivers, especially the Yukon River. The 

other waters moving north are the Bering Sea-shelf water and the Gulf of Anadyr water. These move into 

the Arctic Basin through Herald Valley and around Hanna Shoal. The Siberian Coastal Current flows 

southward along the coast of Russia and is present in summer and fall (Weingartner et al., 1999). 

The semidiurnal tidal range is only 6-10 cm in the Beaufort Sea (Matthews, 1980; Kowalik and Matthews, 

1982; Morehead et al., 1992). Tidal currents generally are weak, about 4 cm/s (Kowalik and Proshutinsky, 

1994). The level of the water changes constantly in response to the wind. Positive tidal surges occur with 

strong westerly winds, while negative surges occur with strong easterly winds. Tides are small in the 

Chukchi Sea, and the range generally is <30 cm. Tidal currents are largest on the western side of the 

Chukchi and near Wrangel Island, ranging up to 5 cm/s (Woodgate, Aagaard, and Weingartner, 2005). 

Waves in the Beaufort and Chukchi seas are controlled by wind and the amount of ice in the water, as ice 

dampens waves. With a solid ice cover, no waves are generated. Under heavy ice-cover conditions during 

 PEA-16 
the colder months, there is little wave development. When the ice thins out, particularly during late 

summer, the available open-water surface increases, and the waves grow in height. Typical wave heights 

are <1.5 m, with a wave period of approximately 6 seconds during summer and <2.5 m during fall. 

Expected maximum wave heights are 7-7.5 m in the Beaufort Sea and 8-9.5 m in the Chukchi Sea (Brower 

et al., 1988). A late summer storm in the Beaufort and Chukchi seas in September 2000 developed waves 

6-7 m high at Point Barrow (Lynch et al., 2003). 

Widespread changes of temperature and salinity occurred in the central Arctic Ocean water column during 

the first half of the 1990-1999 decade. We do not know to what extent the recent changes in the Arctic 

Ocean are cyclical, whether they represent a trend, or if they are a modal shift. There were observations of 

widespread temperature increases in the Atlantic water layer (Carmack et al., 1995; McLaughlin et al., 

1996; Morrison, Steel, and Anderson, 1998; Grotefendt et al., 1998). These appear related to an increased 

temperature (Swift et al., 1998) and strength (Zhang, Rothrock, and Steele, 1998) of the Atlantic inflow 

into the Arctic Basin. Increased transport caused a displacement of the Pacific-Atlantic water boundary 

toward the Canadian Basin. The pronounced warming of Atlantic water in the central basin had tapered off 

by 1998-1999 (Gunn and Muench, 2001; Boyd et al., 2002). Shimada et al. (2004) identify the remnants of 

this warmed Atlantic Water recently reaching the Canadian Basin. Determining whether this trend persists 

depends on acquiring additional data. Polyakov et al. (2005) report two warm Atlantic Water anomalies 

(1999 and 2004) in the eastern Eurasian Basin that will propagate towards the Arctic Ocean interior with a 

time lag. Polyakov et al. (2004) present data showing multidecadal fluctuations in temperature with time 

scales of 50-80 years for Atlantic Water temperature variability. 

The cold haloclyne layer, which insulates the sea ice from the relatively warm Atlantic waters, appears to 

have retreated from the Eurasian Basin in recent years (Steele and Boyd, 1998). This has important 

consequences for ice/ocean-heat exchange and ice-growth rates. Comparisons of recent and historical data 

show that the Canada Basin waters are in transition and are responding to inflow from upstream 

(McLaughlin et al., 2004). The appearance of higher temperatures near the Chukchi Plateau suggests that 

temperatures will continue to increase in the Beaufort Sea in coming years. 

Observations in the next years may be particularly significant in view of the changes observed in the Arctic 

Oscillation, which had a persistent, positive phase through the 1990’s, but it has been negative or near 

neutral for 6 of the years from 1996-2004 (Overland and Wang, 2005). This warming in the early 1990’s 

was thought to be associated with cyclical, large-scale shifts in atmospheric forcing (Proshutinsky and 

Johnson, 1997; Proshutinsky et al., 2000). Even without the driving force of a positive Arctic Oscillation, 

arctic indicators continue to indicate a continuing trend of warming. 

Lynch et al. (2001) examined the Barrow high-wind events from 1960-2000, and concluded that high-wind 

events are common in fall and winter and rare in April, May, and June. They have not yet concluded 

whether the more frequent storms and the storms in April, May, and June are part of a new pattern. The 

longer open-water period and the increase in storm events could lead to increased storm-surge events. 

III.A.1.a. Sea Ice. Sea ice is frozen water with the salt extruded out of the ice mass. The northern 

Alaskan coastal waters are covered by sea ice for three-quarters of the year, from approximately October 

until June. Sea ice has a large seasonal cycle, reaching a maximum extent in March and a minimum in 

September. The formation of sea ice has important influences on the transfer of energy and matter between 

the ocean and atmosphere. It insulates the ocean from the freezing air and the blowing wind. 

There are three major forms of sea ice in the Arctic: landfast ice (which is attached to the shore, is 

relatively immobile, and extends to variable distances offshore); stamukhi ice (which is grounded, ridged 

sea ice); and pack ice (which includes first-year and multiyear ice and moves under the influence of winds 

and currents). 

While there are wide-ranging spatial and temporal variations in arctic sea ice, the generalized annual 

patterns are as follows: 

 PEA-17 
• September – Shore ice forms; the river deltas freeze; and frazil, brash, and greased ice form within 

bays and near the coast. 

• Mid-October – Smooth, first-year ice forms within bays and near the coast. Thomas Napageak 

remarked: “...The critical months [for ice formation] are October, November, and December” 

(Napageak, as cited in Dames and Moore, 1996:7). 

• November through May – Sea ice covers more than 97% of the areas. Spring leads form in the 

Chukchi Sea. 

• Late May – Rivers flood over the nearshore sea ice. 

• Early June – River floodwaters drain from the surface of the sea ice. Sarah Kunaknana stated: “In 

June and July when the ice is rotting in the little bays along the coast....” (Kunaknana, as cited in 

Shapiro and Metzner, 1979). 

The southern Chukchi Sea is free of sea ice 1-2 months longer each year than the northern Chukchi Sea. 

Warmer water flowing north through the Bering Strait, combined with strong sunlight returning earlier in 

the year at lower latitudes, melts or pushes the pack ice north starting as early as mid-June. The same 

effect keeps the surface ice free longer in the fall, typically until mid-November. 

Data obtained from aerial and satellite remote sensing show that leads and open-water areas form within 

the pack-ice zone. Southwesterly storms cause leads to form in the Beaufort and Chukchi seas. Along the 

western Alaskan Coast between Point Hope and Point Barrow, there often is a band of open water seaward 

of the landfast-ice zone during winter and spring. This opening is at some times a well-defined lead and at 

other times a series of openings (polynyas) in the sea ice. Between February and April, the average width 

is <1 kilometer (km) (the extreme widths range from a few kilometers in February to 20 km in April) and is 

open about 50% of the time. The Chukchi open-water system appears to be the result of the general 

westward motion seen in the Beaufort Gyre. There also appears to be a positive correlation between the 

average ice motion away from the coast and the mean wind direction, which is from the northeast for all 

months except July (Stringer and Groves, 1991). 

The analysis of longer term data sets and modeling indicate substantial reductions in both the extent and 

thickness of the arctic sea-ice cover during the past 20-40 years, with record minimum extent in 2002 and 

again in 2005, and extreme minima in 2003 and 2004 (Stroeve et al., 2005; NASA, 2005). 

The extent of arctic sea ice (the area of ocean covered by ice), as observed mainly by satellite, has 

decreased at a rate of about 3% per decade since the 1970’s (Parkinson et al., 1999; Johannessen, Shalina, 

and Miles, 1999). Within Canadian Arctic waters, a similar rate of decrease has been observed over the 

period 1969-2000. In recent years, satellite data have shown a further reduction in ice cover. In September 

2002, sea ice in the Arctic reached a record minimum, 4% lower than any previous September since 1978 

and 14% lower than the 1978-2000 mean (Serreze et al., 2003). Three years of low ice followed 2002. 

Taking these 3 years into account, the September ice-extent trend for 1979-2004 is declining by 7.7% per 

decade (Stroeve et al., 2005). 

Comparison of sea-ice-draft data acquired on submarine cruises between 1993 and 1997, with similar data 

acquired between 1958 and 1976, indicates that the mean ice draft at the end of the melt season has 

decreased by about 1.3 m in most of the deepwater portions of the Arctic Ocean (from 3.1 m in 1958-1976 

to 1.8 m in the 1990’s). The decrease is greater in the central and eastern Arctic than in the Beaufort and 

Chukchi seas (Rothrock and Zhang, 2005). Preliminary evidence is that the ice cover has continued to 

become thinner in some regions during the 1990’s (Rothrock, Yu, and Maykut, 1999). The average 

thinning of the ice appears to be the result of both the diminished fraction of multiyear ice and the relative 

thinning of all ice categories. 

Changes in the landfast ice have been occurring. Events of shorefast ice breaking off have occurred near 

Barrow in January or February and even as late as March (George et al., 2003). These events also have 

increased in frequency. 

 PEA-18 
III.A.2. Air Quality. The combination of limited industrial development and low population density 

results in good to excellent air quality throughout the Chukchi and Beaufort seas area. Only a few small, 

scattered emissions from widely scattered sources exist on the adjacent onshore areas. The only major 

local sources of industrial emissions are in the Prudhoe Bay/Kuparuk/Endicott oil-production complex. 

During the winter and spring, additional pollutants are transported by the wind to the Alaska Arctic Ocean 

from industrial sources in Europe and Asia (Rahn, 1982). These pollutants cause a phenomenon known as 

arctic haze. 

The U.S. Environmental Protection Agency (USEPA) defines Air Quality Control Regions (AQCR’s) for 

all areas of the United States and classifies them based on six “criteria pollutants,” and has established for 

each of them a maximum concentration above which adverse effects on human health may occur. These 

threshold concentrations are called National Ambient Air Quality Standards (NAAQS). When an area 

meets NAAQS, it is designated as an “attainment area.” An area not meeting air quality standard for one of 

the criteria pollutants is designated as a “nonattainment area.” 

Areas are designated “unclassified” when insufficient information is available to classify areas as 

attainment or nonattainment. All areas in and around the Chukchi and Beaufort seas are classified as 

attainment areas. 

The provisions of Alaska’s Prevention of Significant Deterioration (PSD) program are applied to 

attainment areas and unclassified AQCR’s with good air quality to limit its degradation from development 

activities. The areas are classified as PSD Class I, II, or III areas (in decreasing order of relative protection) 

based on land status/use and the associated protection afforded to the area. The region of Alaska adjacent 

to the Chukchi and Beaufort seas is a PSD Class II area. The nearest PSD Class I areas are the Bering Sea 

Wilderness Area within the St. Matthew Island group and the Denali National Park. There are no Class III 

areas in Alaska. States strive to allow industrial and commercial growth within PSD Class II areas without 

causing significant degradation of existing air quality or exceeding the NAAQS. 

III.B. Acoustic Environment. 

Sounds generated by the oil and gas industry are propagated into a marine environment that already 

receives sounds from numerous natural and human sources. Ambient noise levels in the Beaufort and 

Chukchi seas can vary dramatically between and within seasons because of: (1) variability in components 

of environmental conditions such as sea ice, temperature, wind, and snow; (2) the presence of marine 

mammals; (3) the presence of industrial shipping, research activities, and subsistence activities; and (4) 

other miscellaneous factors. In general, the ambient noise in the Arctic marine environment is in the range 

of 63-133 dB (Burgess and Greene, 1999) and varies seasonally. A complete description of all producers 

of noise is beyond the scope of this document. The main sources of noise, both natural and anthropogenic 

(manmade), occurring in the Beaufort and Chukchi seas are described below. 

III.B.1. Existing Environment. The acoustic environment of the Arctic Subregion varies greatly 

among seasons and between specific areas. During much of the year, in many marine areas in this 

subregion, there are few near-field marine-noise sources of human origin and limited, but increasing, landbased sources of noise that affect the OCS in the Arctic Subregion. 

III.B.1.a. Ambient Sound. Natural sound sources in the Beaufort and Chukchi seas include the wind 

stirring the surface of the ocean, lightning strikes; animal vocalizations and noises (including whale calls, 

echolocation clicks, and snapping shrimp); subsea earthquakes; and ice movements. Burgess and Greene 

(1999) report that collectively, these sources create an ambient noise range of 63-133 dB. 

The presence of ice can contribute significantly to ambient noise levels and affects sound propagation. As 

noted by the National Research Council (NRC) (2001:39), “An ice cover radically alters the ocean noise 

field...” with factors such as the “...type and degree of ice cover, whether it is shore-fast pack ice, moving 

pack ice and...floes, or at the marginal ice zone...,” and temperature, all affecting ambient noise levels. 

 PEA-19 
The NRC (2001, citing Urick, 1984) reported that variability in air temperature over the course of the day 

can change received sound levels by 30 dB between 300 and 500 Hertz (Hz). 

Temperature affects the mechanical properties of the ice, and temperature changes can result in cracking. 

In winter and spring, landfast ice produces significant thermal cracking noise (Milne and Ganton, 1964). In 

areas characterized by a continuous fast-ice cover, the dominating source of ambient noise is the ice 

cracking induced by thermal stresses (Milne and Ganton, 1964). The spectrum of cracking noise typically 

displays a broad range from 100 Hz-1 kiloHertz (kHz), and the spectrum level has been observed to vary as 

much as 15 dB within 24 hours due to the diurnal change of air temperature. Ice deformation occurs 

primarily from wind and currents and usually produces low frequency noises. Data are limited, but at least 

in one instance it has been shown that ice-deformation noise produced frequencies of 4-200 Hz (Greene, 

1981). As icebergs melt, they produce additional background noise as the icebergs tumble and collide. 

While sea ice can produce significant amounts of background noise, it also can function to dampen ambient 

noise. Areas of water with 100% sea-ice cover can reduce or completely eliminate noise from waves or 

surf (Richardson et al, 1995a). Because ice effectively decreases water depth, industrial sounds may not 

propagate as well at the lowest frequencies (Blackwell and Greene, 2002). The marginal ice zone, the area 

near the edge of large sheets of ice, usually is characterized by quite high levels of ambient noise compared 

to other areas, in large part due to the impact of waves against the ice edge and the breaking up and rafting 

of ice floes (Milne and Ganton, 1964). In the Arctic, wind and waves (during the open-water season) are 

important sources of ambient noise with noise levels tending to increase with increased wind and sea state, 

all other factors being equal (Richardson et al., 1995a). 

Marine mammals can contribute significantly to the background noise in the acoustic environment of the 

Beaufort and Chukchi seas. Frequencies and levels are highly dependent on seasons. For example, source 

levels of bearded seal songs have been estimated to be up to 178 decibels re 1 microPascal at 1 meter (178 

d re 1 μPa at 1 m) (Cummings et al., 1983). Ringed seal calls have a source level of 95-130 dB re 1 μPa at 

1 m, with the dominant frequency under 5 kHz (Richardson et al., 1995a). Bowhead whales, which are 

present in the Arctic Region from early spring to mid- to late fall, produce sounds with source levels 

ranging from 128-189 dB re 1 μPa at 1 m in frequency ranges from 20-3,500 Hz. Richardson et al. (1995a) 

summarized that most bowhead whale calls are “tonal frequency-modulated (FM)” sounds at 50-400 Hz. 

There are many other species of marine mammals in the arctic marine environment whose vocalizations 

contribute to ambient noise including, but not limited to, the gray whale, walrus, ringed seal, beluga whale, 

spotted seal, fin whale (in the southwestern areas) and, potentially but less likely, the humpback whale. In 

air, sources of sound will include seabirds (especially in the Chukchi Sea near colonies), walruses, and 

seals. 

There is a great deal of naturally occurring noise in the ocean from volcanic, earthquake, wind, ice, and 

biotic sources (see Richardson et al., 1995a:Chapter 5). Ambient noise levels affect whether a given sound 

can be detectable by a receiver, including a living receiver, such as a whale. Ambient-noise levels can 

change greatly throughout the course of a season at a particular site, and vary from site to site. 

III.B.1.b. Anthropogenic Sound. Human sources include noise from vessels (motor boats used for 

subsistence and local transportation, commercial shipping, research vessels, etc.); navigation and scientific 

research equipment; airplanes and helicopters; human settlements; military activities; and marine 

development. Table III.B-1 provides a comparison of manmade sound levels from various sources 

associated with the marine environment. 

III.B.1.b(1) Vessel Activities and Traffic. Shipping noise, often at source levels of 150-190 dB, since 

1950 has contributed a worldwide 10- to 20-dB increase in the background noise in the sea (Acoustic 

Ecology Institute, 2005). The types of vessels that produce noise in the Beaufort and Chukchi seas include 

barges, skiffs with outboard motors, icebreakers, scientific research vessels, and vessels associated with 

geological and geophysical exploration and oil and gas development and production. In the Beaufort and 

Chukchi seas, vessel traffic and associated noise presently is limited primarily to late spring, summer, and 

early autumn. 

 PEA-20 
In shallow water, vessels more than 10 km away from a receiver generally contribute only to background 

noise (Richardson et al., 1995a). In deep water, traffic noise up to 4,000 km away may contribute to 

background-noise levels (Richardson et al., 1995a). Shipping traffic is most significant at frequencies from 

20-300 Hz (Richardson et al., 1995a). Barging associated with activities such as onshore and limited 

offshore oil and gas activities, fuel and supply shipments, and other activities contributes to overall ambient 

noise levels in some regions of the Beaufort Sea. The use of aluminum skiffs with outboard motors during 

fall subsistence whaling in the Alaskan Beaufort Sea also contributes noise. Fishing boats in coastal 

regions also contribute sound to the overall ambient noise. Sound produced by these smaller boats 

typically is at a higher frequency, around 300 Hz (Richardson et al., 1995a). 

Icebreaking vessels used in the Arctic for activities including research and oil and gas activities produce 

stronger, but also more variable, sounds than those associated with other vessels of similar power and size 

(Richardson et al., 1995a). Even with rapid attenuation of sound in heavy ice conditions, the elevation in 

noise levels attributed to icebreaking can be substantial out to at least 5 km (Richardson et al., 1991). In 

some instances, icebreaking sounds are detectable from more than 50 km away. In general, spectra of 

icebreaker noise are wide and highly variable over time (Richardson et al., 1995a). 

III.B.1.b(2) Oil and Gas Development and Production Activities. There currently are a few oilproduction facilities on artificial islands in the Beaufort Sea. Typically, noise propagates poorly from 

artificial islands, as it must pass through gravel into the water (Richardson et al., 1995a). Much of the 

production noise from oil and gas operations on gravel islands is substantially attenuated within 4 km and 

often not detectable at 9.3 km. 

Recently Richardson and Williams (2004) summarized results from acoustic monitoring of the offshore 

Northstar production facility from 1999-2003. Northstar is located on an artificial gravel island in the 

central Alaskan Beaufort Sea. In the open-water season, in-air broadband measurements reached 

background levels at 1-4 km and were not affected by vessel presence. However, Blackwell and Greene 

(2004) pointed out that “...an 81 Hz tone, believed to originate at Northstar, was still detectable 37 km 

from the island.” Based on sounds measurements of noise from Northstar obtained during March 2001 and 

February-March 2002 (during the ice-covered season), Blackwell et al. (2004) found that background levels 

were reached underwater at 9.4 km when drilling was occurring and at 3-4 km when it was not. 

Irrespective of drilling, in-air background levels were reached at 5-10 km from Northstar. 

During the open-water season, vessels such as tugs, self-propelled barges, and crew boats were the main 

contributors to Northstar-associated underwater sound levels, with broadband sounds from such vessels 

often detectable approximately 30 km offshore. In 2002, sound levels were up to 128 dB re 1 μPa at 3.7 

km when crew boats or other operating vessels were present (Richardson and William, 2003). In the 

absence of vessel noise, averaged underwater broadband sounds generally reached background levels 2-4 

km from Northstar. Underwater sound levels from a hovercraft, which BPXA began using in 2003, were 

quieter than similarly sized conventional vessels. 

Typically, noise propagates poorly from artificial islands, as it must pass through gravel into the water 

(Richardson et al., 1995a). Richardson et al. (1995a) reported that during unusually quiet periods, drilling 

noise from ice-bound islands would be audible at a range of about 10 km, when the usual audible range 

would be ~2 km. Richardson et al. (1995a) also reported that broadband noise decayed to ambient levels 

within ~1.5 km, and low-frequency tones were measurable to ~9.5 km under low ambient-noise conditions, 

but were essentially undetectable beyond ~1.5 km with high ambient noise. 

III.B.1.b(3) Miscellaneous Sources. Acoustical systems are associated with some research, military, 

commercial, or other vessel use of the Beaufort or Chukchi seas. Such systems include multibeam sonar, 

sub-bottom profilers, and acoustic Doppler current profilers. Active sonar is used for the detection of 

objects underwater. These range from depth-finding sonar, found on most ships and boats, to powerful and 

sophisticated units used by the military. Sonar emits transient, and often intense, sounds that vary widely 

in intensity and frequency. Acoustic pingers used for locating and positioning oceanographic and 

geophysical equipment also generate noise at high frequencies. LGL, Ltd. (2005) describes many examples 

of acoustic navigational equipment. 

 PEA-21 
III.B.1.c. Potential Effect of Climate Change. Available evidence indicates that the total extent of arctic 

sea ice has declined over the past several decades; these declines are not consistent across the Arctic 

(Gloersen and Campbell, 1991; Johannessen, Miles, and Bjorgo, 1995; Maslanki, Serreze, and Barry, 1996; 

Parkinson et al., 1999; Vinnikov et al., 1999). Warming trends in the Arctic (Comiso, 2003) appear to be 

affecting thickness of multiyear ice in the polar basin (Rothrock, Yu, and Maykut, 1999) and perennial seaice coverage (declines 9% per decade) (Comiso, 2002a,b). 

The presence, thickness, and movement of sea ice significantly influence the ice’s contribution to ambient 

noise levels. The presence of sea ice also affects the timing, nature, and possible locations of human 

activities such as shipping; research; barging; whale hunting; oil- and gas-related exploration (e.g., seismic 

surveys and drilling); military activities; and other activities that introduce noise into the marine 

environment. Because of sea ice and its effects on human activities, ambient noise levels in the Beaufort 

and Chukchi seas can vary dramatically between seasons and sea-ice conditions. The presence of ice also 

impacts which marine species are present, another factor that influences ambient noise levels. 

If arctic warming continues, it is likely that changes in the acoustic environment also will occur in many 

parts of the waters off Alaska (Tynan and DeMaster, 1997; Brigham and Ellis, 2004). Climate warming 

potentially could: (a) increase noise and disturbance related to increased shipping and other vessel traffic, 

and possibly increased development; (b) expand commercial fishing and/or cause a change in areas where 

intensive fishing occurs; (c) decrease year-round ice cover; (d) change subsistence-hunting practices; and 

(e) change the distribution of marine mammal species (MacLeod et al., 2005).

III.B.2. Sound Propagation. Underwater sound essentially is the transmission of energy via compression 

and rarefaction of particles in the conducting medium (i.e., in this case, seawater). The pressure pulse from 

a sound source propagates outwards in an expanding spherical shell at approximately 1,500 meters per 

second (m/s) (in seawater). As the shell expands, the energy contained within it is dispersed across an 

ever-increasing surface area, and the energy per unit area decreases in proportion to the square of the 

distance traveled from the source. 

Properties of sound that influence how far that sound is transmitted, what species hear it, and what physical 

and behavioral effects it can have include: its intensity, frequency, amplitude, wavelength, and duration; 

distance between the sound source and the animal; whether the sound source is moving or stationary; the 

level and type of background noise; and the auditory and behavioral sensitivity of the species (Richardson 

et al., 1995a). The frequency of the sound usually is measured in Hertz, pressure level in microPascals 

(Gausland, 1998), and intensity levels in decibels (Richardson et al., 1995a; McCauley et al., 2000). 

McCauley et al. (2000) and others (see references in McCauley et al., 2000) express this in terms of its 

equivalent energy dB re 1 μPa2

. The perceived loudness of any given sound is influenced by many factors, 

including both the frequency and pressure of the sound (Gausland, 1998), the hearing ability of the listener, 

the level of background noise, and the physical environment through which the sound traveled before 

reaching the animal. 

Based on summaries in key references (e.g., Richardson et al, 1995a; Gausland, 1998; Ketten, 1998), and 

other references as noted, the following information about sound transmission is relevant to understanding 

the characteristics of sound in the marine environment: 

• Sound travels faster and with less attenuation in water than it does in air. 

• The fate of sound in water can vary greatly, depending on characteristics of the sound itself, 

characteristics of the location where it is released, characteristics of the environment through 

which it travels (Richardson et al., 1995a; McCauley et al., 2000), and the characteristics (for 

example, depth, orientation) of the receiver (Richardson et al., 1995a; Gausland, 1998). 

• Sound propagation can vary seasonally in the same environment. 

• Extrapolation about the likely characteristics of a given type of sound source in a given location 

within the Chukchi and Beaufort seas based on published studies conducted elsewhere is 

somewhat speculative, because characteristics of the marine environment such as bathymetry, 

sound-source depth, and seabed properties greatly impact the propagation of sound horizontally 

 PEA-22 
from the source (McCauley et al., 2000; see also Chapter 4 in Richardson et al., 1995a and 

references provided therein). Richardson et al. (1995a:425) summarized that: “...a site-specific 

model of sound propagation is needed to predict received sound levels in relation to distance from 

a noise source.” Especially within the Chukchi Sea Planning Area, differences in site 

characteristics in different parts of the planning area make predictions about sound propagation 

relatively difficult. 

• Because the air-water interface acts as a good reflector, sound generated underwater generally will 

not pass to the air (Gausland, 1998). 

Measurement of underwater sound levels historically has been complicated by a system of inconsistent and 

confusing units. Sound pressures in underwater sound studies are reported in terms of peak-peak, 0-peak, 

peak-equivalent rms, and rms (root-mean-square) (Madsen, 2005). Root-mean-square is linked to the 

derivation of power measurements from oscillating signals. The magnitude of sound pressure levels in 

water normally is described by sound pressure on a decibel scale relative to a reference rms pressure of 1 

μPa (dB re 1 μPa) (Madsen, 2005). 

Results from underwater-noise studies can be difficult to evaluate and compare, as decibel levels may vary 

by 10 dB or more between the different units of measure. Sound pressure of continuous sound sources 

normally is parameterized by an rms measure, while transient sound normally is given in peak pressure 

measures. 

In unbounded seawater (i.e., in the deep oceanic locations, or at close ranges to a source in shallower shelf 

waters), free field spherical spreading will occur. Once the horizontal propagation path becomes 

substantially greater than the water depth, a ducted form of spreading tends to occur due to reflections from 

the seabed and surface. In a duct with perfectly reflective boundaries, the spreading would become 

cylindrical. In reality, the boundaries, and the seabed in particular, are not perfect reflectors, and there is 

some loss of energy from the water column as the sound propagates. When impulse sounds propagate in a 

highly reverberant environment, such as shallow water, the energy becomes spread in time due to the 

variety of path lengths and group velocities supported. The precise rate at which loss will occur is variable 

and will be site specific, depending on such factors as seabed type. 

III.B.3. Seismic Sound. The oil and gas industry in Alaska conducts marine geophysical surveys in the 

summer and fall, and on-ice seismic surveys in the winter, to locate geological structures potentially 

capable of containing petroleum accumulations. These surveys use individual airguns or a combination of 

individual airguns called an airgun array to produce high-energy sound waves that typically are aimed 

directly at the seafloor. The sound is created by the venting of high-pressure air from the airguns into the 

water column and the subsequent production of an air-filled cavity (a bubble) that expands and contracts, 

creating sound with each oscillation. Airgun output usually is specified in terms of zero-to-peak or peakto-peak levels. Airgun sizes are quoted as chamber volumes in cubic inches, and individual guns may vary 

in size from a few tens to a few hundreds of cubic inches. While the seismic airgun pulses are directed 

towards the ocean bottom, sound propagates horizontally for several kilometers (Greene and Richardson, 

1988; Hall et al., 1994). In waters 25-50 m deep, sound produced by airguns can be detected 50-75 km 

away, and these detection ranges can exceed 100 km in deeper water (Richardson et al., 1995a). Typically, 

an airgun array is towed behind a vessel at 4-8 m depth (see Figures I.E-1 and III.B-1) and is fired every 

10-15 seconds. The ship also may be towing long cables with hydrophones (streamers), which detect the 

reflected sounds from the seafloor. 

Airgun-array sizes are quoted as the sum of their individual airgun volumes and again can vary greatly. 

The array output is determined more by the number of guns than by the total array volume (Fontana, 2003, 

pers. commun.). For single airguns the zero-peak acoustic output is proportional to the cube root of the 

volume. As an example, compare two airgun configurations with the same total volume. The first array 

consists of one airgun with a total volume of 100 cubic inches (in3

) resulting in a cube root of 4.64. The 

second array has the same total volume, but consists of five 20-in3

 guns. The second array has an acoustic 

output nearly three times higher (5 times the cube root of 20 = 13.57) than the single gun, while the gun 

volumes are equal. The output of a typical two-dimensional/3-dimensional (2D/3D) array has a theoretical 

point-source output of ~255 dB + 3 dB (Barger and Hamblen, 1980; Johnston and Cain, 1981); however, 

 PEA-23 
this is not realized in the water column, and maximum real pressure is more on the order of 232 dB + 3 dB 

and typically only occurs within 1-2 m of the airguns. 

The depth at which the source is towed has a major impact on the maximum near-field output, and on the 

shape of its frequency spectrum. The root-mean-square (rms) received levels that are used as impact 

criteria for marine mammals are not directly comparable to the peak or peak-to-peak values normally used 

to characterize source levels of airguns. The measurement units used to describe airgun sources, peak or 

peak-to-peak decibels, are always higher than the rms decibels referred to in much of the biological 

literature. A measured received level of 160 dB rms in the far field typically would correspond to a peak 

measurement of about 170-172 dB, and to a peak-to-peak measurement of about 176-178 dB, as measured 

for the same pulse received at the same location (Greene, 1997; McCauley et al., 1998, 2000). The precise 

difference between rms and peak or peak-to-peak values for a given pulse depends on the frequency 

content and duration of the pulse, among other factors. However, the rms level is always lower than the 

peak or peak-to-peak level for an airgun-type source. 

Tolstoy et al. (2004) collected empirical data concerning 190-, 180-, 170-, and 160-dB (rms) distances in 

deep (~3,200 m) and shallow (~30 m) water for various airgun-array configurations during the acoustic 

calibration study conducted by Lamont-Doherty Earth Observatory in the northern Gulf of Mexico. Results 

demonstrate that received levels in deep water were lower than anticipated based on modeling, while 

received levels in shallow water were higher. 

Seismic sounds vary, but a typical 2D/3D seismic survey with multiple guns would emit energy at about 

10-120 Hz, and pulses can contain energy up to 500-1,000 Hz (Richardson et al. 1995a). Goold and Fish 

(1998) recorded a pulse range of 200 Hz-22 kHz from a 2D survey using a 2,120-in3

 array. 

Richardson et al. (1995a) summarized that typical signals associated with vibroseis sound source used for 

on-ice seismic survey sweep from 10-70 Hz, but harmonics extend to about 1.5 kHz (Richardson et al., 

1995a). In this activity, hydraulically driven pads mounted beneath a line of trucks are used to vibrate, and 

thereby energize the ice. Noise incidental to the activity is introduced by the vehicles associated with this 

activity. 

Safety Radii for Marine Mammals. Safety radii traditionally are established around a seismic-survey 

operation to help prevent potential harm to marine mammals that are exposed to the high-energy sound 

sources. The safety radii around an airgun array vary with water depth. Tolstoy et al. (2004) provide both 

predicted and measured values for a variety of airgun configurations ranging from 2-20 airguns. Recent 

National Marine Fisheries Service (NMFS) incidental harassment authorizations (IHA’s) (e.g., LamontDoherty, 2005; University of Alaska, 2005) used the data from Tolstoy et al. (2004) to estimate safety radii 

and exclusion zones for shallow (<100 m), intermediate, (100-1,000 m), and deep (greater than [>] 1,000 

m) waters, depending on the type of airgun configuration used. No measurements were made for 

intermediate-depth waters. The NMFS currently estimates these safety zones using a 1.5x correction factor 

from deepwater data. 

The NMFS has established two levels of harassment: Level A and Level B. Simplified, Level A 

harassment has the potential to injure a marine mammal, while Level B harassment is a disturbance impact. 

Current Level A harassment criteria for nonexplosive sounds are 180 dB for cetaceans and 190 dB for 

pinnipeds. A Level B harassment criterion for impulse noises is 160 dB. These criteria are then coupled 

with existing data (e.g., Tolstoy et al., 2004) or field-test data to determine exclusion zones or safety radii 

on a case-by case basis based on water depths and airgun configurations. Typically, lower output systems 

produce smaller exclusion zones. 

As stated earlier in Section II.A.3 (Alternative 3), the 120-dB isopleth is the approximate zone where 

Richardson et al. (1999) found at 20-km almost total bowhead whale exclusion. Sound levels received by 

bowhead whales at 20 km ranged from 117-135 dB re 1 μPa rms and 107-126 dB re 1 μPa rms at 30 km, 

and it is the level recommended by the 2001 open-water meeting participants to show where significant 

responses by bowhead whales in the Beaufort Sea occurs. An issue complicating the use of the 120-dB 

isopleth for delimiting the exclusion zone is that it lies within the reported ambient range of sounds (66-133 

 PEA-24 
dB) in the marine environment (Burgess and Green, 1999) and, therefore, would be masked by other sound 

sources. 

III.C. Cumulative Activity Scenario. 

This section primarily focuses on those activities and events that could introduce noise into the marine 

environment or otherwise potentially impact local fish, wildlife, and subsistence activities during the period 

of the Proposed Action, specifically the 2006 open-water season. The Proposed Action is to possibly 

permit four marine seismic surveys in both the Chukchi and Beaufort seas in 2006. The scenario will serve 

as the basis for assessing the cumulative impacts (see Sec. III.H - Cumulative Impacts Analysis) of the 

Proposed Action on local fish and wildlife resources and the Inupiat culture that depends on them for 

subsistence-harvest activities. 

The main agents of the cumulative activities scenario are past, present and foreseeable: (1) marine seismic 

surveys; (2) vessel traffic and movements; (3) aircraft traffic; (4) oil and gas exploration in Federal and 

State waters; and (5) miscellaneous activities and factors. Incorporated by reference are the following 

reports and documents, which have a more thorough description of the cumulative activities associated with 

oil and gas exploration and development on the North Slope and neighboring Beaufort and Chukchi seas: 

NRC, 2003; USDOI, BLM and MMS, 1998; USDOI, BLM 2002, 2005. Also see Section III.B for a 

detailed description of the acoustic environment in the Chukchi and Beaufort seas. 

III.C.1. Marine Seismic Surveys in the Beaufort and Chukchi Seas. 

III.C.1.a. OCS Seismic-Survey Activities. The MMS-permitted seismic surveys have been conducted in 

the Chukchi and Beaufort seas since the late 1960’s/early 1970’s. There are currently no active seismicexploration permits in the Beaufort and Chukchi seas. 

Between 1970 and 1975, 12 MMS Geological and Geophysical (G&G) permits were issued for Chukchi 

Sea 2D marine seismic surveys, and no MMS G&G permits were issued between 1976 and 1982. Seismicsurvey activity increased between 1982 and 1991, when MMS issued 30 G&G permits. To date, no 3D 

seismic surveys have been conducted in the Chukchi Sea OCS. Approximately 80,000 line-miles of 2D 

seismic surveys have been collected to date in the Chukchi Sea Planning Area. 

More MMS-permitted seismic activity has occurred in the Beaufort Sea OCS than in the Chukchi Sea OCS. 

The 2D marine seismic surveys in the Beaufort Sea began with two G&G permits issued in 1968 and four 

in 1969. Both over-ice (29 G&G permits) and marine (43 G&G permits) 2D seismic surveys were 

conducted in the 1970’s. With one exception, the 80 marine and 43 over-ice surveys permitted in the 

Beaufort Sea OCS by MMS in the 1980’s were 2D. In the 1990’s, both 2D (2 over-ice and 21 marine) and 

3D (11 over-ice and 7 marine ocean-bottom-cable [OBC]) seismic surveys were conducted. The first 3D 

over-ice survey occurred in the Beaufort Sea OCS in 1983 and the first marine (OBC) 3D seismic survey 

occurred in 1996. More than 100,000 line-miles of 2D and 3D seismic surveys have been collected to date 

in the Beaufort Sea Planning Area. 

The most G&G permits issued in any one year in the Chukchi Sea was seven (6 marine and 1 over-ice) in 

1986. In the Beaufort Sea, 23 MMS G&G permits were issued in 1982 (11 marine and 12 over-ice 2D 

surveys) and 24 MMS G&G permits were issued in 1983 (1, 3D over-ice survey; 14, 2D over-ice surveys; 

and, 9, 2D marine surveys). Figures III.C-1, III.C-2, and III.C-3 illustrate cumulatively, the geographic 

extent of OCS-permitted seismic surveys conducted in the Beaufort and Chukchi seas beginning in the 

1970’s and through 2004. 

As part of a lease agreement between the MMS and lessee and per regulations (30 CFR 250), highresolution site-clearance surveys are conducted on leased blocks, along with side-scan sonar surveys to 

detect geohazards, archaeological resources, and certain types of benthic communities. Such highresolution data may be used for initial site evaluation for drilling rig emplacement and for platform or 

pipeline design and emplacement. In the 1980’s, five high-resolution site-clearance surveys were 

 PEA-25 
conducted in the Chukchi Sea OCS prior to five exploration wells being drilled. To date, high-resolution 

site-clearance surveys in the Beaufort Sea OCS were conducted for 30 exploration wells. Additional siteclearance surveys may have been conducted in the Proposed Action area where no exploration wells were 

drilled. No high-resolution site-clearance surveys are expected to occur in the Chukchi Sea in 2006, and 

none would be expected to occur until after proposed Chukchi Sea Lease Sale 193 in 2007. In the Beaufort 

Sea OCS, site-clearance surveys in 2006 are expected on up to three oil and gas prospects. 

Given the growing interest of oil and gas companies to explore and develop oil and gas resources on the 

Arctic Ocean OCS, there is the potential that seismic surveys will continue in the Chukchi and Beaufort 

seas beyond 2006. Surveys beyond 2006 are dependent on: (1) the amount of data that is collected in 

2006; (2) what the data indicate about the subsurface geology; and (3) the results of Beaufort Sea Sale 202 

and Chukchi Sea Sale 193. Table III.C-1 provides information about the potential level and type of 

seismic-survey activities that may occur in the Beaufort and Chukchi seas between 2006 and 2010. 

Potential seismic-survey activity beyond 2006 will be addressed in the draft EIS for the OCS Oil and Gas 

Leasing Program, 2007 to 2012. The MMS anticipates that future seismic surveys will focus on areas 

surrounding currently and previously leased blocks in the Beaufort and Chukchi seas. Figure III.C-4 

illustrates the existing locations of MMS OCS leases in the Beaufort Sea, and Figure III.C-5 illustrates the 

locations of those MMS OCS blocks previously leased to the oil and gas industry in the Chukchi Sea. All 

of these leases have been relinquished or expired. 

III.C.1.b. State of Alaska Seismic-Survey Activities. Seismic surveys for exploration purposes in State 

of Alaska (State) waters (mean high tide line to 3 miles [mi] offshore) are authorized under Miscellaneous 

Land Use Permits; however, seismic surveys conducted for other purposes, such as shallow hazard 

assessments, do not require permits unless they are not conducted from the ice and/or involve contact with 

the seafloor (Schultz, pers. commun., as cited in Wainwright, 2002). 

Since 1969, the State has issued 42 permits for seismic-survey activities in the Beaufort Sea. The number 

and types of airgun-type seismic permits issued since then are as follows: 

• 1969 1 2D 

• 1970’s 23 20, 2D marine streamer and 3, 2D OBC 

• 1980’s 13 2D marine streamer 

• 1990’s 3 2, 3D OBC and 1, 2D marine streamer 

• 2000-2002 3 3D OBC 

• 2002 to date 0 

To date, the State has not issued any seismic survey permits for the Chukchi Sea (Rader, ADNR, pers. 

commun.). One permit is likely to be issued in 2006 by the State for an OBC seismic survey in the 

Beaufort Sea. Table III.C.1 provides information about what the State of Alaska believes will be the level 

and type of seismic-survey activities occurring in the Beaufort and Chukchi seas between 2006 and 2010. 

III.C.1.c. Other Seismic-Survey Activities. Occasionally, seismic surveys are conducted in the Arctic 

Ocean for scientific-research purposes. These surveys often use seismic-research vessels that employ a 

variety of airgun configurations, as well as multibeam bathymetric sonar, a sub-bottom profiler, and other 

standard acoustic-research instrumentation. The MMS issues geophysical scientific-research permits for 

any oil- and gas-related investigation conducted in the OCS for scientific and/or research purposes. 

Historically the MMS rarely issued such permits for the Beaufort and Chukchi seas, and none are expected 

to be issued in 2006 or the foreseeable future. The MMS is aware of at least one non-oil- and gas-related 

scientific seismic survey that will be conducted in and near the project action area in 2006. The University 

of Texas, Austin, with research funding from the National Science Foundation plans to conduct a marine 

seismic survey in the western Canada Basin, Chukchi Borderland, and Mendeleev Ridge, Arctic Ocean, 

during approximately July 15 to August 25, 2006. The project will include collection of seismic reflection 

and refraction data as well as sediment coring. Additional information about the University of Texas’s 

research is located at http://www.nsf.gov/od/opp/arctic/arc_envir/healy_ea_06.pdf. 

 PEA-26 
A seismic-survey similar to the proposed 2D survey in the Chukchi Sea is expected to be conducted in late 

summer to early fall 2006 in the Mackenzie Delta region of the Canadian Beaufort Sea. No additional 

activities in the Russian Chukchi Sea have been identified that would occur during the time period covered 

in this PEA. 

III.C.2. Vessel Traffic and Movements. Vessels are the greatest contributors to overall noise in 

the sea. Sound levels and frequency characteristics of vessel noises underwater generally are related to 

vessel size and speed. Larger vessels generally emit more sound than smaller vessels, and those underway 

with a full load, or those pushing or towing a load, are noisier than unladen vessels. The primary sources of 

sounds are engines, bearings, and other incidental mechanical parts. The sound from these sources reaches 

the water through the vessel hull. The loudest sounds are made by the spinning propellers. Navigation and 

other vessel-operation equipment also generate subsurface sounds. 

Aside from seismic survey vessels associated with the Proposed Action, overall vessel traffic in the 

Proposed Action area is expected to be limited. The majority of other vessels expected to transit through 

the Proposed Action area and/or within 12.5 mi (20 km) of the coast and will include, at a minimum, 

vessels used for fishing and hunting, cruise ships, icebreakers, Coast Guard vessels, and supply ships and 

barges (LGL Alaska Research, 2006). 

The Beaufort and Chukchi seas, unlike other OCS areas in the United States, do not support an extensive 

maritime industry transporting goods between major ports. However, during ice-free months (June to 

October), barges are used for supplying the local communities, Alaskan Native villages, and the North 

Slope oil-industry complex at Prudhoe Bay with larger items that cannot be flown in on regular commercial 

air carriers. Barge-transported commodities include diesel fuel for electric power generation, gasoline and 

other petroleum products, raw materials, and manufactured goods. Usually, one large fuel barge and one 

supply barge visit the villages per year and one barge per year traverses through the Arctic Ocean to the 

Canadian Beaufort Sea. 

Existing oil-field developments on the North Slope are serviced by land, air, and sea. Tug and barge traffic 

associated with the onshore oil-development travel mainly in nearshore waters along the coast. Major 

sealifts into the industrial complex at Prudhoe Bay occur frequently. Between 1968 and 1990, 

approximately 480 sealifts (averaging 22 per year) were made to Prudhoe Bay, which corresponds to the 

time period when the complex was constructed and subsequently expanded. Since then, approximately 40 

sealifts have been made to Prudhoe Bay (averaging 2-3 per year); however, in many years, no sealift 

occurred. 

The Proposed Action area lies within the Northwest Passage, and from the first transit through 2004, 99 

vessel transits (62 eastbound and 37 westbound), mostly by icebreakers, have occurred. Twenty-seven of 

these carried passengers (Brigham and Ellis, 2004). Arctic marine transport in the Proposed Action area is 

likely to increase as indicated by the following: from 1977-2005 there have been 61 North Pole transits (17 

in just the last year) and 7 trans-Arctic voyages (Brigham, 2005). Cargo transport in the Arctic (primarily 

outside the Chukchi and Beaufort seas area) is also expected to increase due to increased petroleum and 

mining activities and the need for future supplies for these industries (PAME, 2000). 

Service vessels that support various requirements of offshore oil and gas activities are categorized into 

supply, crew, and utility vessels, each of which produce noise above and under water; discharges; and air 

emissions. Service-vessel trips usually are greatest during exploration, drilling, and construction phases 

and are greatly reduced during the production phase. 

Vessel strikes and gear interactions with marine mammals, a biological resource category of concern in this 

PEA, in the Arctic Ocean is rare, in part because commercial fisheries and overall vessel traffic in the 

Alaska Beaufort Sea are very limited. The rate of interactions may have increased slightly in recent years 

(NMFS, 2003a). 

 PEA-27 
III.C.3. Air Traffic. Underwater sounds from aircraft are transient, that is, passing quickly into and 

out of existence. The primary sources of aircraft noise are the engine(s) (either reciprocating or turbine) 

and rotating rotors or propellers. Sound levels from both helicopters and fixed-wing aircraft are at 

relatively low frequencies (usually below 500 Hz) and are dominated by harmonics associated with the 

rotating propellers and rotors (Smith, 1989; Hubbard, 1995). The duration of sound from a passing aircraft 

is variable, depending on the aircraft type, direction of travel, receiver depth, and altitude of the source 

(Green, 1985). 

Aircraft are used in the Beaufort and Chukchi seas area for transporting supplies and personnel to local 

communities and industrial complexes (e.g., Deadhorse, Prudhoe Bay, and Red Dog Mine); conducting 

research (e.g., marine mammal and marine bird surveys); recreation and tourism; monitoring weather and 

oceanographic conditions; and military exercises and surveillance. Much of this air traffic occurs over 

land. 

In 2006, MMS will continue its annual Bowhead Whale Aerial Survey Program (BWASP), which usually 

begins September 1 and ends October 20. All surveys would be conducted at an elevation between 1,000 

and 1,500 feet (ft). Other marine mammal research-related aerial surveys are likely to occur in the Arctic 

Ocean in 2006, and possibly at elevations lower than 1,000 ft. 

Hovercraft and helicopter support has largely replaced crew boat traffic to the Northstar Island oil 

production facility during the open-water season. 

The Proposed Action is expected to generate some aircraft traffic, as helicopters may be used to transport 

personnel and supplies to and from the seismic survey vessels. 

III.C.4. Oil and Gas Development in Federal and State Waters.

III.C.4.a. Federal OCS Activities. The following summary of OCS-related oil and gas activities contains 

information obtained from MMS’ Liberty Development and Production Plan EIS (USDOI, MMS, 2002) 

and Beaufort Sea multiple-sale EIS (USDOI, MMS, 2003a). 

There have been no lease sales and virtually no petroleum exploration in the Chukchi Sea since 1991. Two 

lease sales were held on different parts of the Chukchi OCS in 1988 and 1991, but only a small fraction of 

the tracts were leased by industry (483 leases, or approximately 5% of the tracts offered). The northeast 

portion of the current Chukchi Planning Area was part of the Beaufort Planning Area until 1995 and was 

offered for lease in several Beaufort sales. Five exploration wells drilled in 1989-1991 tested five large 

prospects, none of which resulted in commercial-size discoveries. There have been no active leases in the 

Chukchi Sea since 1998. 

In February 2005, the MMS issued a Call for Information to the oil and gas industry and found that there 

was renewed interest in leasing blocks in the Chukchi Sea. Based on this show of interest, MMS issued a 

Notice of Intent in September 2005 indicating that MMS planned to prepare an EIS and proposed to hold 

Lease Sale 193 in the Chukchi Sea. The lease sale is scheduled to occur in late 2007 or later, pending 

decisions in the 2007-2012 5-Year OCS Leasing Program. 

The seven Beaufort Sea lease sales that occurred between 1979 and 1998 resulted in 686 issued leases. 

During 20 years in the Beaufort Sea, the oil and gas industry has drilled 30 exploration wells, and 10 leases 

have been determined capable of producing. Of the 686 original leases, 592 have been relinquished or have 

expired. As a result of Beaufort Sea Sales 186 and 195 under the current 5-year program, a total of 151 

leases were awarded. As of January 2006, there are 181 active leases in the Beaufort Sea Planning Area. 

Geological and geophysical information obtained from exploratory seismic surveys in 2006 is needed for 

the oil and gas industry to effectively participate in MMS-proposed Chukchi Sea Lease Sale 193 and 

Beaufort Sea Lease Sale 202, which are part of MMS’ current 5-year program that expires in July 2007. As 

required by the OCS Lands Act, MMS has prepared a draft proposed 5-year program (2007-2012) to 

 PEA-28 
succeed the current program, and it is currently under public review. The new 5-year program proposes to 

conduct lease sales in the Chukchi Sea in 2010 (Sale 211) and 2012 (Sale 221) and in the Beaufort Sea in 

2009 (Sale 208) and 2011 (Sale 216). In those leased blocks proposed for exploration drilling or 

development and production, geological site surveys and shallow hazard surveys would be required. Table 

III.C-2 lists the anticipated lease sales in both State and Federal OCS waters. 

III.C.4.b. State of Alaska Activities. The following summary of State of Alaska activities contains 

information obtained from MMS’ Liberty Development and Production Plan EIS (USDOI, MMS, 2002) 

and the Bureau of Land Management’s (BLM’s) Northeast NPR-A final Amended Integrated Activity 

Plan/EIS (USDOI, BLM, 2005). Since 1959, the State has held 32 oil and gas lease sales involving the 

North Slope and Beaufort Sea, resulting in more than 4.6 million acres being leased. About 78% of the 

leased areas are onshore, and about 22% are offshore. Of the leased tracts, about 10% actually have been 

drilled, and about 5% have been developed commercially. From the early 1960’s through 1997, 401 

exploration wells were drilled in State onshore and offshore areas. Fifty-three of the exploration wells have 

resulted in discoveries. From 1990 through 1998, the number of exploration wells drilled annually has 

averaged about 10 per year. 

The State develops and approves an oil and gas leasing plan for a 10-year period. The State reassesses the 

plan, and publishes a schedule every other year. Except for the Northstar development, all of the North 

Slope and Beaufort Sea’s commercially producible crude oil is on 931 active State leases (as of December 

2000). The State held a Beaufort Sea lease sale on March 1, 2006, and drew 76 bids for 62 tracts, covering 

231,680 acres. 

III.C.5. Miscellaneous Activities and Factors. Miscellaneous activities possibly contributing 

to the cumulative effects on the PEA’s resources of concern include subsistence-harvest activities, military 

activities, industrial and community development, and climate changes. 

III.C.5.a. Subsistence-harvest Activities. The Inupiat people’s entire history, culture, and identity have 

revolved around their subsistence-harvest activities lifestyle, and only within the last 60 years have seminomadic Inupiat settled into sedentary villages and been subjected to managed hunts (USDOI, BLM, 2005). 

The collapse of the whaling industry in 1910 coincided with a depletion in the number of whales available 

for harvest, making the ongoing subsistence harvest difficult for the Inupiat remaining along the Arctic 

coast. The U.S. Department of Defense (USDOD) construction on the North Slope and oil exploration 

resulted in additive impacts on subsistence resources, harvest patterns, and users. The most intense oil and 

gas development activity, and increased impacts to subsistence activities, occurred during the 1970’s and 

early 1980’s with the development of the Prudhoe and Kuparuk oil fields and the construction of the TransAlaska Pipeline System (TAPS) and haul road. Subsistence is part of the rural economic system of the 

North Slope, called a “mixed subsistence-market” economy, wherein families invest money into smallscale, efficient technologies to harvest wild foods (USDOI, BLM, 2005). 

III.C.5.b. Military Activities. Unlike in other OCS areas of the United States, the surface and airspace of 

the Beaufort and Chukchi seas are not used extensively by the military for testing, evaluating, training, and 

qualification of aircraft, vessels, weapon systems, and personnel. On occasion, military vessels may transit 

through the area, and military personnel may conduct winter survival exercises. No military vessels or 

aircraft are home ported or stationed in the Beaufort and Chukchi seas. None of the airspace over the 

Chukchi and Beaufort seas is reserved by the Federal Aviation Administration as “special use airspace” for 

the military. 

Past military activities were primarily associated with operations of the Defensive Early Warning system 

(DEW-Line), which was an integrated chain of radar and communications sites stretching across Alaska, 

Northern Canada and Greenland. The DEW-Line was initiated in 1954 and, of the 22 sites built in Alaska, 

14 were located along the coast of the North Slope. The Dew-Line program was discontinued in 1963 and 

replaced with long- and short-range radar. Some stations are still manned, but most were abandoned in the 

1990’s. The USDOD’s Formerly Used Defense Sites program is in the process of dismantling the 

abandoned sites and cleaning up any associated contaminated soil. 

 PEA-29 
III.C.5.c. Industrial Development. The terrestrial environment adjacent to the Beaufort Sea has 

experienced most of the industrial development on the North Slope. Oil and gas exploration and 

production activities have occurred on the North Slope since the early 1900’s, and production has occurred 

for more than 50 years. Associated industrial development has included the creation of an industry-support 

community airfield at Deadhorse and an interconnected industrial infrastructure that includes roadways, 

pipelines, production and processing facilities, gravel mines, and docks (Figure III.C-6). 

Since the discovery and development of the Prudhoe Bay and Kuparuk oil field, more recent fields 

generally have been developed not in the nearshore environment, but on land in areas adjacent to existing 

producing areas. Notable exceptions to this are the Northstar, Endicott, and Badami fields. Pioneer Natural 

Resources Co. is beginning the development of its North Slope Oooguruk field, which is in the shallow 

waters of the Beaufort Sea approximately 8 mi northwest of the Kuparuk River unit. In the 2006 winter 

construction season, Pioneer will build an ice road over which they will haul gravel for the installation of 

an offshore gravel drilling and production facility. In addition, some open-water activities this summer will 

involve placing armor (gravel bags) on the side slopes of the gravel island to protect it from erosion. A 

subsea flowline and flowline facilities will be installed during 2007 to carry produced liquids to existing 

onshore processing facilities at the Kuparuk River unit. Ongoing oil-development projects such as Badami 

and Alpine do not have permanent gravel roads connecting to Prudhoe Bay. Transportation would occur 

via aircraft and marine vessels in ice-free conditions. In winter, temporary ice roads are used. 

The Northstar facility was just issued a Letter of Authorization under the Marine Mammal Protection Act 

(MMPA) (71 Federal Register [FR] 11314) from the NMFS to cover Level A and Level B taking of 

bowhead, gray, and beluga whales, and ringed, spotted, and bearded seals, incidental to operation of the 

facility. This includes potential effects from presence of personnel, structures, and equipment; oil spills; 

on-ice construction or transportation; vessel and helicopter activity; and acoustic impacts from power 

generation and oil production; but it excludes seismic-survey operations. 

Transportation to and from Northstar Island during the ice-covered season is primarily by hovercraft, 

tracked vehicles, and standard tired vehicles. In 2004, helicopters made approximately 250 round trips 

during the broken-ice periods and approximately 190 trips to Northstar during the open-water period (LGL, 

2005). A small hovercraft made approximately 140 roundtrips during the broken ice period and 

approximately 300 round trips during the open water season (LGL, 2005). Barges made 24 round-trips to 

and from the island during the period July 29 to October 3, 2004, and a fuel transfer was made in August 

2004 (LGL, 2005). 

Although permitted, no construction work is planned in 2006 on Kerr-McGee’s three Nikaitchuq oil- and 

gas-production gravel islands in the Beaufort Sea. In 2006, Shell is planning to conduct on-ice, shallow 

boring in Beaufort Sea State waters between its offshore Hammerhead leases and the shoreline within the 

Point Thomson unit. 

On the Chukchi Sea west of the North Slope major industrial complex and outside the southern boundary of 

the proposed action area, the major industrial developments have been and continue to be associated with 

Red Dog Mine and Delong Mountain Terminal (DMT). These facilities are included in the cumulative 

activities scenario, because their activities have the potential to affect the Programmatic Environmental 

Assessment’s (PEA’s) biological resources of concern (e.g., marine mammals and marine birds) that 

migrate just offshore of the facilities into the marine waters of the Proposed Action area. 

Red Dog mine is the world’s largest producer of zinc concentrate, and mining operations have reserves for 

40-plus years. The DMT receives ore concentrate from the Red Dog Mine and stores it until the Chukchi 

Sea is ice free in the area. About 250 barge trips per year are needed to transfer 1.5 million tons of 

concentrate a year to bulk cargo ships, which are anchored 6 mi offshore due to the shallow depths at the 

terminal. About 27 cargo ships are loaded each year. The U.S. Army Corps of Engineers is in the process 

of evaluating the feasibility of expanding the DMT port, so that deep-draft cargo ships can access the 

terminal directly instead of having to be loaded 6 mi offshore. Other development projects involving the 

Red Dog Mine facility being proposed in the foreseeable future include building a road to connect Noatak 

 PEA-30 
airport to the Red Dog Mine and developing the Deadfall Syncline Coal Mine near Point Lay, which would 

require the construction of a 90-mi-long road to the DMT. 

III.C.5.d. Community Development. The following seven Alaskan Native communities located on the 

North Slope and vicinity, and their associated growth and development, are considered part of the 

cumulative scenario: Kaktovik, Barrow, Nuiqsut, Atqasuk, Wainwright, Point Hope, and Point Lay. Most 

of these communities’ populations are increasing annually, with Barrow having the largest population of 

approximately 4,400 people. These communities have been established or reestablished since 1900 and 

consist of dwellings and other private and commercial buildings, gravel roads, gravel airstrips/airports, and 

other structures. For a more detailed description of each community and the status of future capital 

improvement projects see the State of Alaska, Community Online Database web site: 

http://www.dced.state.ak.us/dca/commdb/CF_COMDB.htm 

Nearshore development activities in some of the aforementioned communities, notably in Barrow and 

Kaktovik, include curtailing shoreline erosion. If this activity requires fill material to be placed in 

navigable waters of the United States, a Section 10/404 permit from the U.S. Army Corps of Engineers 

would be required. The MMS does not anticipate any community development projects occurring in the 

nearshore environment of the Beaufort and Chukchi seas. 

III.C.5.e. Climate Change. Global and regional climates have changed throughout the Earth’s history, 

but warming during the past several decades on the North Slope and vicinity has been unusually rapid 

(NRC, 2003). Changes associated with arctic warming complicate and confound the assessment and 

isolation of the effects of oil and gas activities on the North Slope and the Beaufort and Chukchi seas. If 

recent warming trends continue, their effects could accumulate to alter the extent and timing of sea ice; 

affect the composition, distribution, and abundance of marine and terrestrial plants and animals; affect 

permafrost; affect existing oil-field infrastructure; and affect coastal Alaskan Native subsistence cultures 

(NRC, 2003). 

Ice cover in the Arctic Ocean has been shrinking by about 3% per decade over the past 20 years 

(Johannessen, Shalina, and Miles, 1999). The loss of sea ice would reduce necessary habitat for marine 

mammals and seabirds that use ice shelves and floes as platforms for feeding, resting, reproducing, and 

molting. The increases in the amount and duration of open water could make the Northwest Passage more 

available for ocean transport and improve opportunities for offshore oil and gas development and military 

naval operations (NRC, 2003). Accompanying increases of vessels movements are the increased risks of 

environmental effects caused by spills, noise, or collisions. 

III.D. Preliminary Screening of Seismic-Survey Activities and Potential 

Impacts. This preliminary screening focuses the more detailed environmental impact analysis on those 

resources most at risk for potential adverse impacts from seismic survey operations as described in earlier 

sections of the PEA. 

Relevant literature (NRC, 2003, 2005); previous environmental documents (USDOI, MMS, 2002, 2003a, 

2004; USDOI, BLM and MMS, 1998; USDOI, BLM, 2005); professional judgment; and traditional 

knowledge about marine seismic-survey operations and the biological resources of the Beaufort and 

Chukchi seas were used to initially identify the following resources and activities for impact analysis: 

• Air Quality 

• Archaeological Resources 

• Marine Invertebrates 

• Coastal Wetlands 

• Coastal and Marine Birds 

• Essential Fish Habitat 

• Marine Fish 

• Freshwater Fish 

 PEA-31 
• Commercial Fisheries 

• Geology and Sediments 

• Marine Mammals 

• Sociocultural Resources 

• Subsistence Activities 

• Terrestrial Mammals 

• Water Quality 

• Aquatic Invasive Species 

In this preliminary analysis, a matrix was prepared listing the categories of seismic-survey impact agents 

and the above list of resource categories of concern (Table III.D-1). The “level of impact” associated with 

each interaction was ascertained as either: (1) potentially adverse; (2) likely negligible; (3) not likely; or 

(4) not applicable. Those resources having any potential to be adversely impacted by any impact agent are 

environmentally analyzed in more detail in Sections III.F (Biological Resources), III.G (Community 

Setting), and III.H (Cumulative Impacts Analysis). In addition, Section IV (Summary of Findings, 

Mitigation Measures, and Recommendations) addresses what actions should be taken to ensure that seismic 

surveys in 2006 operate in an environmentally sound manner, do not cause significant impacts, and do not 

interfere with subsistence-harvest activities of the Inupiat community. 

III.D.1. Resources Not Considered Further. The preliminary screening indicates that airgun 

noises have the greatest potential to cause adverse impacts. Vessel and aircraft traffic, vessel noise and 

lights, and seafloor disturbances associated with OBC seismic surveys also have associated potential 

adverse impacts. 

The following resources were determined to be negligibly or not impacted by the Proposed Action, and are 

not considered further beyond the analysis provided in the sections that follow. 

III.D.1.a. Air Quality. Air emissions from seismic operations arise primarily from the main engines and 

generators of the seismic ship and support vessel. A typical seismic vessel has up to 8,000 kilowatts (kW) 

of engine propulsion power, consuming 20-30,000 liters (L) of fuel per day (WesternGeco, 2005). In 

addition to the seismic vessel, operations in the Chukchi and Beaufort seas will require an additional 

support vessel to serve as a resupply, fueling, and chase vessel, which also would be capable of assisting 

with ice management, if needed. The support vessel would contribute up to 6,000 kW of additional engine 

propulsion power to the mix of engines in a typical seismic operation. Table III.D-2 lists the potential to 

emit (PTE) for a likely seismic operation in the Chukchi and Beaufort seas. It assumes an average seismic 

survey of approximately 5,556 km (3,252 mi) as described in recent IHA’s. The PTE calculations represent 

a worst-case estimate of pollutants emitted by each seismic operation, based on emission factors and 

operating assumptions listed in Table III.D-3. It is likely that actual emissions would be significantly less 

than the PTE, because not all emission sources would be operating 100% of the time. 

The significance criteria used in the impact analysis for air quality is whether emissions cause an increase 

in pollutants over an area of at least a few tens of square kilometers that exceeds half the increase permitted 

under the PSD criteria or the NAAQS for nitrogen dioxide, sulfur dioxide, or particulate matter <10 

microns in diameter; or exceeds half the increase permitted under the NAAQS for carbon monoxide or 

ozone. Table III.D-4 lists the emission thresholds for PSD and NAAQS analysis. 

To assess the significance of emissions from anticipated seismic operations in the Chukchi and Beaufort 

seas, we reviewed the analysis of potential air quality impacts for the proposed Liberty development and 

production facility (USDOI, MMS, 2002). Table III.D-5 lists the PTE for criteria pollutants for the Liberty 

project. Air quality modeling for Liberty shows that at distances greater than 1-2 km from the proposed 

facility, the highest predicted concentrations of criteria pollutants were less than half the maximum 

allowable increases under PSD regulations. The conclusion for the Liberty analysis was that the predicted 

increase in pollutant concentrations was below the significance threshold. Comparatively speaking, the 

PTE for seismic operations is appreciably less than the PTE calculated for the Liberty project, and pollutant 

concentrations are spread out over a significantly broader area. Accordingly, the predicted increase in 

 PEA-32 
pollutant concentrations for marine seismic work at distances greater than 1-2 km from the seismic vessel 

would be appreciably below the significance threshold. 

Marine seismic operations would cause only a short-term, local increase in the concentration of criteria 

pollutants. Emissions would be within NAAQS. In addition, because emissions would be from mobile 

sources, they would be spread over a substantially larger area and are expected to be rapidly dispersed by 

prevailing offshore winds. The potential impacts to air quality from marine seismic work in the Chukchi 

and Beaufort seas are therefore considered negligible. 

III.D.1.b. Coastal Wetlands. All marine seismic surveys that are part of the Proposed Action would 

occur in Federal waters and outside the boundaries of State of Alaska waters, which lie between the meanhigh-tide-line and the 3-mi limit. Seismic surveys operating near the 3-mi limit would generate highenergy acoustic sounds that would spread towards shore. However, because of ice scouring during 

breakup, no wetlands exist along the exposed Beaufort and Chukchi seas coastline. Wetlands do occur 

landward of barrier islands in protected bays and lagoons. The small amount (<5 gallons [gal]) of 

anticipated individual petroleum spills are not expected to affect coastal wetlands and associated fish and 

wildlife resources. Overall, the Proposed Action’s seismic activities are not likely to have any adverse 

impacts on coastal wetlands and the fish and wildlife resources they support. 

III.D.1.c. Freshwater Fishes. The Proposed Action scenario considers seismic surveys to be conducted 

on the OCS in Federal waters of the Chukchi and Beaufort seas; it does not include seismic surveys being 

conducted in freshwater environments of the North Slope. While seismic surveys using airguns operating 

in Federal waters may ensonify nearshore waters, airguns would not be expected to ensonify lacustrine 

(e.g., lakes) or fluvial (e.g., rivers) habitats used by freshwater fishes. Freshwater fishes are not likely to be 

exposed to airgun emissions, wastewater discharges, and accidental spills from vessels, and are not 

considered further. Anadromous and/or amphidromous fishes that also use freshwater environmental 

waters may be exposed to airgun emissions, and are considered further. 

III.D.1.d. Geology and Sediments. Bottom sampling and shallow coring, which are typical G&G 

activities that can disturb, resuspend, and create minor surficial features, are not part of the Proposed 

Action. Conducting OBC seismic surveys does require placing instruments (hydrophones) on the seafloor 

and later retrieving them. Normally, this activity does not alter the local geology or surficial sediment 

features of the ocean bottom. However, during storm events some cables could become partially buried, 

when bottom sediments are shifted around. Retrieving cables under these circumstances likely would cause 

negligible, short-term impacts, such as localized turbidity, as the cable are pulled out of the seafloor 

sediment and hauled back on board a vessel. 

III.D.1.e. Terrestrial Mammals. Terrestrial mammals would not be impacted by the acoustic energy 

generated by airguns. Offshore vessel movements, lights, and sounds may alert terrestrial mammals of 

human presence and cause wildlife to flee the area or, in some cases, cause wildlife to be curious about the 

offshore activity and linger. Survey-related aircraft also may startle wildlife and cause them to flee the 

area. The small amount (<5 gal) of anticipated individual petroleum spills are not expected to affect 

terrestrial mammals. Overall, the Proposed Action’s seismic activities are not likely to have any adverse 

impacts on terrestrial mammals. 

III.D.1.f. Water Quality. Marine water quality could be affected by accidentally spilled lubricating oil or 

diesel fuel from vessels and equipment associated with seismic survey operations. The MMS believes that 

the risk of vessel collisions is low, and the incidents involving the release of oil and fuel from vessels 

during refueling will likely be small, on the order of <5 gal per refueling event (40 gal total potentially 

spilled). Vessel collisions with ice are not likely to occur, because seismic surveys will be conducted in 

relatively ice-free conditions. Vessels colliding with each other or equipment-entanglement problems also 

are not likely to occur, because vessels are required maintain a minimum separation of at least 15 mi. 

We assume that there would be no unauthorized discharges, such as engine oil, etc., from the seismic 

vessel. Therefore, any effects would be due to accidental discharges, such as a spill of fuel oil during a fuel 

transfer from a support vessel to a seismic vessel. The analysis further assumes that the operators would be 

 PEA-33 
cautious and vigilant during fuel transfers; for example, if a fuel hose broke, the fuel valves would be shut 

off quickly. 

A previous assessment of Chukchi Sea exploration included the effects of seismic exploration and of small 

spills (USDOI, MMS, 1990a). The assessment distinguished the effects during the open-water and icecovered seasons; the Proposed Action seismic surveying would be conducted during the open-water season. 

The 1990 assessment explains that a 1,000-barrel (bbl) spill in restricted waters during flat calm might 

exceed the applicable ambient-water-quality standards. The assessment does not include a conclusion 

specifically about the effect of a spill of a few barrels or a few gallons. The effects of the latter in offshore 

waters during normal conditions probably would not exceed the standards and might be unmeasurable. The 

Beaufort Sea multiple-sale EIS also assessed the effects of a 1,000-bbl spill, concluding that the effects 

would be low regionally, but moderate locally (USDOI, MMS, 2003a). The effect of spills of a few barrels 

or a few gallons is not assessed. Again, the effects of the latter probably would be unmeasurable. 

III.D.1.g. Aquatic Invasive Species. The introduction of aquatic invasive species (AIS) into a marine 

ecosystem potentially could result in adverse impacts. Such introductions occur when species establish 

self-sustaining populations beyond their historical geographic ranges. On February 13, 2003, the 

International Maritime Organization agreed to the International Convention for the Control of Ship’s 

Ballast Water & Sediments. The Convention will enter into force 12 months after the date on which at 

least 30 nations, representing more than 35% of the World Merchant Shipping tonnage, ratify it. Nations 

that are party to the Convention are given the right to implement additional, more stringent measures than 

are provided in the Convention. The Convention’s ballast-water-management regulations would apply to 

both port nations and flag nations that ratify the Convention. Under the Convention, all new and existing 

vessels with ballast tanks are required to implement a ballast-water-management plan when entering a 

nation’s waters from outside its exclusive economic Zone (EEZ). The Convention specifies both an interim 

ballast-water-exchange standard (efficiency of 95% volumetric exchange) and ballast-water-performance 

standards (reduce the concentration of viable organisms per unit volume discharges). The Convention 

provides for a phasing-in period through 2016 for new and existing vessels to meet requirements. 

The U.S. Coast Guard developed regulations (33 CFR 151) that implements provisions of the 

Nonindigenous Aquatic Nuisance Prevention and Control Act of 1990 (NANPCA) (16 U.S.C. 4701-4751) 

as amended by the National Invasive Species Act of 1996 (NISA). The NISA reauthorized the Great Lakes 

ballast-management program and expanded NANPCA’s applicability to vessels with ballast tanks (as 

opposed to vessels that carry ballast water). The NISA required the development of national guidelines to 

prevent the introduction and spread of nonindigenous species into U.S. waters via ballast water of 

commercial vessels. Under NISA, the Coast Guard may approve alternative ballast-water-management 

technologies that are at least as effective as ballast water exchange in preventing invasions. This began the 

Shipboard Technology Evaluation program a voluntary, experimental, 5-year research and development 

program to bring about a 98% reduction in the number of live organisms found in ballast water. As 

required under NEPA, the U.S. Coast Guard prepared a Programmatic Environmental Assessment for 

Ballast Water Management Program for U.S. Waters 

(http://dmses.dot.gov/docimages/pdf87/250004_web.pdf) that was published in June 2003. The purpose of 

that environmental assessment was to revise 33 CFR 151 as required by NISA. 

In June 2004, the Coast Guard made mandatory the voluntary measures to comply with NISA, with the 

primary means of prevention being exchange of ballast water on the high seas. The regulations mandate a 

ballast water management program and reporting requirements. The rule specifically addresses all vessels 

equipped with ballast tanks bound for ports or places within the U.S. and/or entering U.S. waters. At this 

time, midocean ballast-water exchange is the most practicable method to help prevent the introduction of 

invasive species into U.S. waters. There is no international consensus on a water-depth criterion for 

ballast-water exchange. The Coast Guard considers that any ballast-water-management plan that meets 

International Maritime Organization guidelines meets the regulatory requirements of 151.2035. Vessels 

that conduct coastwise trade (within the 200-mi EEZ) are not addressed in the final 2004 regulations 

because they cannot conduct a mid-ocean ballast water exchange. The Coast Guard is examining the 

possibility of establishing alternative ballast water-exchange zones. The coastwise trade vessels are still 

required to submit ballast-water reporting forms. 

 PEA-34 
Potential vectors for introducing aquatic invasive species (AIS) are ballast-water discharge, hull fouling, 

and equipment placed overboard (e.g., anchors, seismic airguns, hydrophone arrays, OBC). Seismic survey 

vessels for the Proposed Action may be brought in from other U.S. or foreign waters. Vessels brought into 

State of Alaska or Federal waters would be subject to current Coast Guard regulations at 33 CFR 151, 

which are intended to reduce the transfer of invasive species. Section 151.2035 (a)(6) requires the 

“removal of fouling organisms from hull, piping, and tanks on a regular basis and dispose of any removed 

substances in accordance with local, State, and Federal regulations.” 

More than 180 marine seismic surveys have been performed in Arctic OCS waters under G&G permits 

since 1968, and more than 40 marine seismic surveying operations have been permitted and completed in 

adjacent State waters (see Sec. III.C.1.a and b). To date, no AIS studies have been conducted nor have any 

AIS been documented in the Alaskan Chukchi or Beaufort seas. The Chukchi and Beaufort seas pose harsh 

and frigid environmental conditions that are believed to impose major and difficult challenges to AIS’s that 

might be introduced into the region’s waters by vessels or equipment. Therefore, the likelihood of AIS 

successfully being introduced into the Arctic Ocean from the Proposed Action is considered to be low, and 

this issue is not considered further in this PEA. 

III.D.2. Resources to be Evaluated in Greater Detail. The preliminary screening indicates 

that marine seismic surveys potentially could adversely impact archaeological sites, marine invertebrates, 

coastal and marine birds, essential fish habitat, marine fish, commercial fisheries, marine mammals, the 

sociocultural environment, and subsistence-harvest activities. The rest of the impact analysis focuses 

mainly on these resources of concern. 

III.E. Significant Impact Criteria. 

The Council on Environmental Quality (CEQ) National Environmental Policy Act (NEPA) regulations (40 

CFR 1500-1508) defines the term “significantly” in terms of both context and intensity (40 CFR 1508.27). 

“Context” considers the setting of the Proposed Action, what the affected resource might be, and whether 

the effect on this resource would be local or more regional in extent. Factors to be considered in evaluating 

“intensity” include: (1) the severity of the impact; (2) whether the impact is beneficial or adverse; (3) the 

degree to which the Proposed Action affects public health and safety; (4) the unique characteristics of the 

affected area; (5) the degree of controversy; (6) uncertainty; (7) establishing precedence; (8) the 

cumulative, direct, and indirect aspects of the impact; (9) the affects upon endangered or threatened 

species; and (10) whether Federal, State, or local laws may be violated. 

Our analyses address the significance of the Proposed Action’s potential impacts on the biological and 

cultural resources, considering such factors as the nature of the impact (e.g., habitat disturbance or 

mortality); the spatial extent (local and regional); temporal and recovery times (years, generations); and the 

effects of mitigation and any associated mitigation monitoring plan. Impacts to some environmental 

resources may be measurable, but are considered insignificant, because their potential effects and 

contribution to cumulative effects (additive, synergistic and countervailing) would be minimal and/or short 

term. Our analyses also consider whether proposed mitigation measures can reduce or eliminate all or part 

of the potential adverse effects. Mitigation measures that reduce adverse impacts to below “significance 

thresholds” are incorporated into the alternatives. 

III.E.1. Significance Thresholds for Resource Categories. For this document, we have 

defined a “significance threshold” for each Arctic Ocean resource category as the level of effect that equals 

or exceeds the adverse changes indicated: 

• Threatened and Endangered Species of Whales (Bowhead, humpback, and fin whales): An 

adverse impact that could affect the survival and reproduction of twelve or more whales (of an 

affected species and/or stock) annually. See Section III.E.2 for an explanation of this significance 

threshold. 

 PEA-35 
• Threatened and Endangered Species of Birds (spectacled and Steller’s eiders): An adverse 

impact that results in a decline in abundance and/or change in distribution requiring one or more 

generation for the indicated population to recover to its former status. 

• Biological Resources (seals, walrus, beluga whale, gray whale, polar bear, marine and 

coastal birds, lower trophic-level organisms, and fish/fishery resource and essential fish 

habitat [EFH]): An adverse impact that results in an abundance decline and/or change in 

distribution requiring three or more generations (or having an impact lasting 10 or more years) for 

the indicated population to recover to its former status, and one or more generations for “rare” fish 

resources (see section III.F.1 – Fish/Fishery Resources and EFH for a discussion about “rare” fish 

resources) and their EFH, and polar bears.

• Subsistence-Harvest Patterns: One or more important subsistence resources would become 

unavailable, undesirable for use, or available only in greatly reduced numbers for a period of 1-2 

years. 

• Sociocultural Systems: Chronic disruption of sociocultural systems occurs for a period of 2-5 

years, with a tendency toward the displacement of existing social patterns. 

• Archaeological Resources: An effect-producing factor produces a loss of unique archaeological 

information. 

• Environmental Justice: The significance threshold for Environmental Justice would be 

disproportionate, high adverse human health or environmental effects on minority or low-income 

populations. This threshold would be reached if one or more important subsistence resource 

becomes unavailable, undesirable for use, or available only in greatly reduced numbers for a 

period of 1-2 years; or chronic disruption of sociocultural systems occurs for a period of 2-5 years, 

with a tendency toward the displacement of existing social patterns. Tainting of subsistence foods 

from oil spills and contamination of subsistence foods from pollutants would contribute to 

potential adverse human-health effects. 

III.E.2. Criteria for the Evaluation of the Potential for Significant Effects on 

Endangered Whales. In determining the potential significance of the Proposed Action to bowhead 

whales and other endangered whales, we considered the following NEPA-relevant factors: unique 

characteristics of the geographic area; degree of controversy; degree of highly uncertain effects or unique 

or unknown risks; precedent-setting effects; cumulative effects; adverse effects on scientific resources (we 

evaluate cultural effects in other portions of this document); and violations of Federal, State, or local 

environmental law. We based our conclusions also on consideration of 1) NMFS (2005; Angliss and 

Outlaw, 2005) potential biological removal estimates and determination of removal level that would be 

“significant” to the population, and 2) NRC Guidance on Determining when Noise Causes Biologically 

Significant Effects (NRC, 2005:3). 

1) The NMFS (2005; Angliss and Outlaw, 2005) potential biological removal estimates and 

determination of removal level that would be “significant” to the population. Under the MMPA, the 

term “potential biological removal level” means the maximum number of animals, not including natural 

mortalities, that may be removed from a marine mammal stock while allowing that stock to reach or 

maintain its optimum sustainable population. The potential biological removal level is the product of the 

following factors: (A) The minimum population estimate of the stock; (B) One-half the maximum 

theoretical or estimated net productivity rate of the stock at a small population size; and (C) A recovery 

factor of between 0.1 and 1.0. 

In the most recent stock assessment for the western Arctic or Bering-Chukchi-Beaufort seas stock of 

bowhead whales, NMFS (Angliss and Outlaw, 2005) stated that: 

Under the 1994 reauthorized Marine Mammal Protection Act (MMPA), the potential biological 

removal (PBR) level is defined as the product of the minimum population estimate, one-half the 

maximum theoretical net productivity rate, and a recovery factor: PBR = NMIN x 0.5RMAX x FR. 

The recovery factor (FR) for this stock is 0.5 rather than the default value of 0.1 for endangered 

species because population levels are increasing in the presence of a known take (see guidelines 

Wade and Angliss 1997). Thus, PBR = 95 animals (9,472 x 0.02 x 0.5) The development of a 

 PEA-36 
PBR level for the Western Arctic bowhead stock is required by the MMPA even though the 

subsistence harvest is managed under the authority of the International Whaling Commission 

(IWC). Accordingly, the IWC bowhead whale quota takes precedence over the PBR estimate for 

the purpose of managing the Alaska Native subsistence harvest from this stock. For 2002-07, a 

block quota of 280 bowhead strikes will be allowed, of which 67 (plus up to 15 unharvested in the 

previous year) could be taken each year. This quota includes an allowance of 5 animals to be taken 

by Chukotka Natives in Russia. 

Thus, since we are evaluating only one year of potential effects, if Alaska Native and Russian Native 

hunters took the maximum number of whales allowed in their quota from the population in 2006, a 

potential of 82 whales could be taken by subsistence hunters leaving 13 animals that theoretically could be 

removed from the population while allowing that stock to reach or maintain its optimum sustainable 

population (OSP). This assumption of take by subsistence hunters is the maximum that could be taken, but 

exceeds the average number of whales taken in recent years. NMFS (Angliss and Outlaw, 2005) gives the 

estimated average annual mortality rate incidental to commercial fisheries as 0.2 (which is equal to the 

estimated annual rate of entanglement in crab pot gear for 1999-2003). Thus, assuming that 1 whale may 

be taken incidental to commercial fisheries in 2006, that 82 may be taken in the subsistence hunt, and that 

PBR = 95, 12 whales could be removed from the population from all other anthropogenic causes while 

allowing this stock to reach or maintain its OSP. However, with respect to the “significance of take” of 

bowheads from this population in commercial fisheries, NMFS (Angliss and Outlaw, 2005) summarized 

that: “...the estimated annual mortality rate incidental to commercial fisheries (0.2) is not known to exceed 

10% of the PBR (9.4) and, therefore, can be considered to be insignificant.” 

Thus, based on the aforementioned logic, and based on the assumption that the loss of animals from the 

population from any source other than subsistence take is of equal “significance” we assume that removing 

more than 12 bowheads from this population stock would be significant. This level of removal underlies 

our evaluation of significance. 

The MMS does not expect the Proposed Action to result in serious injury or death of bowhead whales. 

Level B harassment (behavioral disturbance) potentially could reach significance, if it reached a level 

which resulted in the effective loss of 12 animals to this population over that expected given normal 

survival and birth rates. 

This theoretically could be achieved by reducing the reproductive capacity of the stock to the point that 

results in 12 or fewer animals being recruited annually, or lowers the survival rate of the population to the 

point which is equivalent to the immediate loss of 12 whales. 

2) NRC Guidance on Determining when Noise Causes Biologically Significant Effects. The NRC 

(2005:3) reviewed and characterized “current scientific understanding of when animal behavior 

modifications induced by transient and non-transient ocean acoustic sources, individually or cumulatively, 

affect individuals in ways that have negative consequences for populations.” Their charge was to “clarify 

the term biologically significant” (NRC, 2005:3). The NRC (2005:3-4) summarized that 

An action or activity becomes biologically significant to an individual animal when it affects the 

ability of the animal to grow, survive, and reproduce. Those are the effects on individuals that can 

have population-level consequences and affect the viability of the species. However, those effects 

are separated in time and usually in space from the precipitating event. What can be observed, 

with difficulty..., are the direct behavioral and in some cases physiological responses of individual 

animals...On reflection, it became clear that wild animals rarely engage in activities that are not 

biologically significant...so the primary concern should be with determining when human activity 

elicits behavioral or physiological responses in marine mammals that rise to the level of biological 

significance. 

Changes in behavior that lead to alterations in foraging efficiency, habitat abandonment, declines 

in reproduction, increases in infant mortality and so on are difficult to demonstrate in terrestrial 

animals...and more difficult to demonstrate in animals that may only rarely be observed.... 

 PEA-37 
The NRC (2005:x) further stated that “...today many important habitat threats involve habitat degradation 

and the cumulative effects of harassment.” 

The NRC (2005:9) encouraged precautionary management in instances when there is greater uncertainty 

about the potential population effects of behavioral changes resulting from noise exposure. They 

specifically (NRC, 2005:10) recommended that “mortality equivalents for injury and disruption need to be 

added to the biological removal...” in the PBR model “...to encompass the multitude of effects, including 

acoustic effects, of human activities on marine mammal populations.” They recommended that NMFS 

“...expand the PBR model to include injury and behavioral disturbance with appropriate weighting factors 

for severity of injury or significance of behavioral response” (NRC, 2005:10). 

In discussing the uncertainty around determining the biological significance of marine mammal responses 

to sound, the NRC (2005:xi) stated that: 

A basic tenet of responsible management and conservation is the need to balance the risks posed 

by overregulation and those posed by underregulation; the latter carry more weight in conditions 

of greater uncertainty...The depth of our uncertainty in these issues can make it difficult to 

calibrate the proper extent of precaution...For most other...[other than effects on beaked whales 

lethal strandings]...the primary source of uncertainty stems from our difficulty in determining the 

effects of behavioral or physiological changes on an individual animal’s ability to survive, grow, 

and reproduce.

III.F. Biological Resources.

III.F.1. Fish/Fishery Resources and Essential Fish Habitat. 

III.F.1.a. Introduction. This section focuses on coastal and marine fish/fishery resources and habitats 

occurring in nearshore and offshore waters of the Chukchi and Beaufort seas. The proposed seismic-survey 

activity would be conducted in Federal waters offshore and, therefore, likely would not impact freshwater 

habitats. In addition, there are few commercial fisheries in the Alaskan Beaufort and Chukchi seas and, 

therefore, there are few species covered by fishery-management plans in these waters. Presently, the five 

species of Pacific salmon occurring in Alaska are the only managed species with essential fish habitat 

(EFH) designated in the Alaskan Beaufort and Chukchi seas. Pacific salmon and their EFH are described 

later herein. 

III.F.1.b. Major Surveys of Coastal and Marine Fish Resources and Habitats. To appreciate the state 

of information concerning coastal and marine fish resources of the Chukchi and Beaufort seas and their 

habitats, it is informative to briefly review some important surveys conducted in these waters in the last 

century. 

Walters (1955) briefly summarized the history of arctic Alaska ichthyology to date. He wrote: “The 

ichthyofauna of western Arctic America has been studied the least of any major sector of the northern polar 

regions, and that of Arctic Alaska the least of any equally great area of North America” (Walters, 1955). 

Fifty years later, Walters’ comment remains, for the most part, accurate. 

The first major scientific collections of fishes in the Chukchi Sea were those made by the Russians A.P. 

Andriyashev, K.I. Panin, and P.V. Ushakov in 1932 and 1933 (Raymond, 1987). Andriyashev (1955; a 

translation of a report published in 1937) described basic information concerning fishes collected by 

Russian expeditions of the Bering and Chukchi seas. Collections were made in depths chiefly from 20-235 

m. In 1932, about 1,500 fish were collected and in 1933, 1,700 fish were collected. Using data collected 

by these and other Russian expeditions made in the first half of the last century, Andriyashev (1964) 

published Fishes of the Northern Seas of the U.S.S.R. in 1954. Much of the information contained in this 

classic treatise remains the best information we have on the biology and ecology of western Arctic fishes. 

 PEA-38 
Frost and Lowry (1983) reported on thirty-five successful otter-trawl tows that were conducted in the 

northeastern Chukchi and western Beaufort seas in August-September of 1976 and 1977. In 1976, two 

tows were made in the western Beaufort Sea in water 40 m and 123 m deep. In 1977 (August 2-September 

3), 33 tows were made in the northeastern Chukchi and western Beaufort seas in waters 40-400 m deep. 

Many were conducted near the southern edge of pack ice. Frost and Lowry (1983) caught 133 fishes 

belonging to 14 species in trawls made in 1976. In the more extensive trawls conducted in 1977, they 

caught 512 fishes belonging to 17 species. A total of 19 species or species groups of fishes were identified 

from the combined tows. Three fish species (arctic cod, polar eelpout, and twohorn sculpin) accounted for 

65% of all fishes caught. Eight species were represented by five or fewer specimens. Pelagic species such 

as salmonids and osmerids were not adequately sampled by the otter trawl. Epifaunal invertebrates, 

including brachyuran crabs (e.g., snow crab) also were collected and reported from this survey. Frost and 

Lowry’s surveys are the latest surveys made of demersal marine fishes in the western Beaufort Sea. 

Fechhelm et al. (1984) reported results of an ichthyological survey conducted in 1983 focused primarily on 

arctic fish usage of and ecological dependence on marine estuarine environments along the northeastern 

Chukchi Sea coast from Peard Bay to Point Hope. Data were collected for the most part during the openwater, summer season and, to a lesser extent, in winter. Their survey revealed the most prominent species 

encountered during 1983 were arctic cod, arctic staghorn sculpin, fourhorn sculpin, capelin, shorthorn 

sculpin, hamecon, arctic founder, and saffron cod. Fourhorn sculpin and arctic flounder occurred in 

nearshore waters (<1 km), while the remaining sculpins were found exclusively in deeper, offshore (>1 km) 

waters. Arctic cod and saffron cod were found to occupy both nearshore and offshore waters. 

Barber, Smith, and Weingartner (1994) reported data obtained during five summer and autumn research 

cruises conducted in the northeastern Chukchi Sea between Cape Lisburne in the south to the ice edge in 

the north between 1989 and 1992. In 1989 and 1990, sampling stations were trawled for demersal and 

midwater fishes using one of two otter trawls. Additionally, young-of-the-year fishes and larvae were 

sampled with a midwater trawl and bongo net. In 1991 and 1992, additional sampling was conducted to 

gain wider coverage; estimate interannual variability of abundance, biomass, and species; and to collect 

reproductive data on snow crab. Techniques used in sampling during 1991 were identical to those of 

earlier years. Results of the surveys are detailed in Barber, Smith, and Weingartner (1994) and multiple 

papers published in American Fisheries Society Symposium 19 (American Fisheries Society, 1997). The 

Barber, Smith, and Weingartner surveys (1989-1992) are the most recent fish surveys conducted within the 

Chukchi Sea Planning Area. 

A 3-year study (1988, 1990, and 1991) of epipelagic fishes inhabiting Beaufort Sea coastal waters in 

Alaska documented spatial and temporal patterns in fish distribution and abundance and examined their 

relationships to thermohaline features during summer (Jarvela and Thorsteinson, 1999). Significant 

interannual, seasonal, and geographical differences in surface water temperatures and salinities were 

observed. In 1990, sea ice was absent and marine conditions prevailed whereas in 1988 and 1991, heavy 

pack ice was present and the dissolution of brackish water along the coast proceeded more slowly. Arctic 

cod, capelin, and snailfishes were the most abundant marine fishes in catches, while arctic cisco was the 

only abundant diadromous species. The epipelagic fish survey is the most recent pelagic fish survey 

conducted in the western Beaufort Sea. 

In the summer of 2004, an expedition, the Russian-American Long-term Census of the Arctic 

(RUSALCA), was conducted in the Bering and Chukchi seas. The primary study area lay between 

Wrangel Island and Herald Canyon in Russia Federation territorial waters to Cape Lisburne, Alaska, to 

Point Barrow, Alaska, and south to the Bering Strait. Most of sampling sites lie to the south and west of 

the Chukchi Sea Planning Area; however, three sampling sites occur on the southern margins of the 

planning area (off Cape Lisburne). Samples and data collected from this survey have not been analyzed 

past some preliminary findings by the researchers; funding is required to complete the analysis 

(Mecklenburg and Norcross, 2006, pers. commun.). Findings reported herein are preliminary according to 

the researchers. 

One objective of the RUSALCA expedition was to sample fish species presence, distribution, relative 

abundance, and association in the environment. At 17 sites, larval and juvenile fishes were collected using 

 PEA-39 
both a plankton net and a bottom trawl. The bottom trawl collected 1,307 fishes, including fishes of at least 

31 species. 

Another objective of the RUSALCA expedition was to determine the baseline ichthyological resource of 

the northern Bering Sea and Chukchi Sea and to contribute to knowledge of the species’ morphology and 

external appearance, focusing as collection of specimens permitted, particularly on the least well-known 

species. An otter trawl was used to collect benthic fishes; 27 tows were made at depths from 34-101 m, 

and a total of 1,883 individual fishes were collected representing at least 25 species (Mecklenburg et al., 

2005). Species caught in greatest numbers by both trawl types (otter trawl for demersal adult fishes; beam 

trawl for larval and juvenile fishes) were (1) Arctic staghorn sculpin and (2) shorthorn sculpin. Bering 

flounder and arctic cod were third and fourth most abundant species caught in the otter trawl and combined 

catch, whereas hamecon and stout eelblenny were third and fourth in the beam trawl. The differences 

reflect gear selectivity. The four most abundant species by number (arctic staghorn sculpin, shorthorn 

sculpin, Bering flounder, and arctic cod) composed 80% of the combined catch. 

Fish biologists on the RUSALCA expedition noted the following qualitative conclusions: (1) the Chukchi 

benthic community is highly diverse and patchy, and (2) that both fish abundance and diversity seem lower 

in the Chukchi Sea than in the Bering Sea. The largest catches occurred to the south, and were usually at 

least one order of magnitude higher than those in the north. Also, biologists noted several range 

extensions—a small Bering flounder was collected ca. 72o 18' N. latitude in the eastern Chukchi Sea, and a 

walleye pollock was collected at 71o 23' N. latitude. Biologists also noted that their collections include 

specimens of rare species. 

Collectively, these surveys and associated studies reflect a sparse sampling of fish resources across the 

northeastern Chukchi and western Beaufort seas. Sampling effort has been spatially and temporally 

irregular and disjunct. For example, coastal waters of the western Beaufort Sea are better sampled than 

coastal waters of the northeastern Chukchi Sea, and offshore waters of the western Beaufort Sea are poorly 

sampled relative to coastal waters. Fish surveys of the northeastern Chukchi Sea in the last 30 years 

essentially are limited to those conducted in 1976-1977 (Frost and Lowry, 1984), 1983 (Fechhelm et al., 

1984), and 1989-1992 (Barber, Smith, and Weingartner, 1994, 1997); therefore, offshore waters of the 

northeastern Chukchi Sea Planning Area was last surveyed for fish resources 14-17 years ago. Nearshore 

waters of the northeastern Chukchi Sea were last surveyed 23 years ago (i.e., 1983). Marine pelagic fishes 

landward of the 20-m isobath were sampled in the western Beaufort Sea as recently as 15 years ago; marine 

demersal fishes were last sampled 29 years ago (i.e., 1977). Plainly, these limited surveys reflect great 

lapses in time occurring among and between surveys, relative to this baseline description. 

Surveys often have been directed at one fish assemblage (e.g., subadult and adult demersal fishes) and, 

consequently, did not sample for other fish assemblages (pelagic life stages and species). Information from 

many surveys was reported only for abundant species, and that information was not standardized; hence, 

biological statistics such as fecundity, age at maturation, or stomach contents are reported for one species 

but not for others. Similar information concerning less abundant (e.g., uncommon and rare) species 

collected in surveys often are not reported. Such species simply “fall through the cracks” and often are 

ignored until evidence is presented indicating the species is threatened with extirpation or extinction, if at 

all. Finally, surveys of coastal and marine fish resources in the Chukchi and Beaufort seas are typically 

conducted during periods that ice cover is greatly reduced (late July, August, or September). Therefore, 

information concerning the distribution, abundance, habitat use, etc., of all marine fishes (abundant, 

uncommon, or rare species) outside this period is extremely scant. The survey information shows that (1) 

resulting data are dated; (2) sampling effort has been irregular and disjunct in space and time and of fish 

resources; these two factors introduce large information gaps that subsequently influence the certainties of 

the impacts assessment. 

III.F.1.c. Fish Resources of Arctic Alaska and Their Ecology. Three large marine ecosystems (LME’s) 

encompass coastal and offshore waters of arctic Alaska. They are the Bering Sea, Chukchi Sea, and the 

Beaufort Sea. Each large marine ecosystem is characterized by distinct hydrographic regimes, submarine 

topographies, productivity, and trophically dependent populations, yet influences the others. The Chukchi 

Sea LME represents a transition zone between the fish assemblages of the Beaufort and Bering LME’s. 

 PEA-40 
The Beaufort and Chukchi seas off Alaska support species representative of jawless fishes (hagfishes and 

lampreys); cartilaginous fishes (sharks, rays, and chimaeras); and bony fishes (fishes whose skeletons are 

composed mostly of bone instead of cartilage, the most diverse grouping). At least 98 fish species, 

representing 23 families (Table III.F.1) have been documented to occur (Mecklenburg, Mecklenburg, and 

Thorsteinson, 2002). These families include: lampreys, sleeper sharks, dogfish sharks, herrings, smelts, 

whitefishes, trouts and salmons, lanternfishes, cods, sticklebacks, greenlings, sculpins, sailfin sculpins, 

fathead sculpins, poachers, lumpsuckers, snailfishes, eelpouts, pricklebacks, gunnels, wolffishes, sand 

lances, and righteye flounders. Lanternfishes have yet to be documented in the Alaskan portion of the 

Chukchi Sea. Dogfish sharks, sailfin sculpins, and gunnels have been documented in the Beaufort Sea, but 

not the Chukchi Sea. Forty-nine species are common to both large marine ecosystems. 

Additional species are likely to be found in Alaskan waters of either the Chukchi or Beaufort seas when 

coastal and offshore waters are more thoroughly surveyed. For example, the shulupaoluk (Lycodes 

jugoricus) was collected by N.J. Wilimovsky in the Chukchi Sea (Walters, 1955); and McAllister (1962) 

collected two specimens in brackish waters of the Beaufort Sea at Herschel Island, Yukon Territory, 

Canada. Shulupaoluk is a name applied by Ungava Eskimos to an eelpout (McAllister, 1962, citing Dunbar 

and Hildebrand, 1952); to date, a shulupaoluk has yet to be documented as occurring in the Alaskan 

Beaufort Sea, although based on the noted collections, the species is likely to occur there. 

Aquatic systems of the Arctic undergo extended seasonal periods of frigid and harsh environmental 

conditions; therefore, fish inhabiting such systems must be biologically and ecologically adapted to 

surviving such conditions so as to produce offspring that eventually do the same. Important environmental 

factors that arctic fishes must contend with include reduced light, seasonal darkness, prolonged low 

temperatures and ice cover, depauperate fauna and flora, and low seasonal productivity (see McAllister, 

1975 for a description of environmental factors relative to arctic fishes). During the 8- to 10-month winter 

period, freezing temperatures may reduce nearshore and freshwater fish habitat by more than 95% (Craig, 

1989). Furthermore, over wintering stream habitat may be reduced by as much as 97-98% by late winter 

(Craig, 1989). The lack of sunlight and extensive ice cover in arctic latitudes during winter months 

influence primary and secondary productivity, making food resources very scarce during this time, and 

most of a fish’s yearly food supply must be acquired during the brief arctic summer (Craig, 1989). There 

are fewer fish species inhabiting Arctic waters of Alaska as compared to those inhabiting warmer regions 

of the State. The Chukchi Sea is warmer, more productive, and also supports a more diverse fish fauna 

than occurs in the western Beaufort Sea (Craig, 1984, citing Morris, 1981; Craig and Skvorc, 1982; Craig, 

1989). Also, most fish species inhabiting the frigid polar waters are thought to grow and mature more 

slowly relative to individuals or species inhabiting boreal, temperate, or tropical systems. 

The Alaskan Arctic includes a variety of aquatic areas that may be exploited by fish. The Alaskan arctic 

coastline shapes the transitional and dynamic nearshore brackish ecotone (i.e., coastal waters) that results 

from the mixing of fluvial freshwaters from the Alaskan Arctic Coastal Plain with marine waters of the 

Beaufort and Chukchi seas. Marine waters of the Beaufort and Chukchi seas offer the greatest two- and 

three-dimensional area for arctic fishes to exploit; these include neritic waters and substrates (occurring 

landward of the continental shelf break, as delimited by the 200-m isobath) and oceanic waters and 

substrates (occurring seaward of the continental shelf break [>200-m isobath]). 

The diverse fishes of the eastern Chukchi and western Beaufort seas use a range of waters and substrates 

for spawning, breeding, feeding, or growing to maturity. The range of waters and substrates are 

hierarchically organized in Table III.F.2 for suitable analysis of fishes relative to their environment. Table 

III.F.2 also shows each species’ occurrence by hierarchical category. 

Primary Fish Assemblages. Biologists studying arctic fishes of Alaska have classified them into primary 

assemblages by occurrence in basic aquatic systems and by life-history strategies that allow the fishes to 

survive the frigid polar conditions (Craig, 1984; Craig, 1989; Moulton and George, 2000; Gallaway and 

Fechhelm, 2000). A life-history strategy is a set of co-adapted traits designed by natural selection to solve 

particular ecological problems (Craig, 1989, citing Stearns, 1976). 

 PEA-41 
The primary assemblages of arctic fishes are: 

• freshwater fishes that spend their entire life in freshwater systems (although some also might 

spend brief periods in nearshore brackish waters); 

• marine fishes that spend their entire life in marine waters (some also spend brief periods in 

nearshore brackish waters along the coast); and 

• diadromous and anadromous fishes that move between and are able to use fresh, brackish, and/or 

marine waters due to various biological stimuli or ecological factors. 

In the last several decades, biologists have described the fish assemblages occurring in freshwater systems 

(Moulton and George, 2000) or nearshore brackish waters along the mainland and inner barrier island 

coasts (Craig, 1984, 1989; Jarvela and Thorsteinson, 1999; Gallaway and Fechhelm, 2000). Far fewer 

reports are available describing fishes in marine waters, especially those exceeding 2 m in depth (e.g., Frost 

and Lowry, 1983; Jarvela and Thorsteinson, 1999). Scientific information on marine fishes inhabiting 

waters more than approximately 12 mi (20 km) from the Alaskan coastline (excluding barrier islands) is 

limited. Due to the lack of specific information for many species, it is necessary to discuss the biology and 

ecology at the family level. Appendix B (Profiles of the Families of Fish and Selected Species that Occur 

in the Alaska Arctic Ocean) provides generalized life-history strategies of the families with fish species 

known to be occurring in the region. Most of this information is taken from Mecklenburg, Mecklenburg, 

and Thorsteinson (2002) Fishes of Alaska. Following the family accounts are select species accounts for 

species that we have more information to draw upon. 

While some arctic fish species are described in the scientific literature and in surveys as being abundant in 

the region, they are only so in a relative context and are of low overall abundance. For examples, Frost and 

Lowry (1983) sampled demersal fishes of the northeastern Chukchi and western Beaufort seas using 35 

successful otter-trawl tows in 1976-1977 and caught 645 fishes. Three species (arctic cod, polar eelpout, 

and two horn sculpin) accounted for 65% of all fishes caught (i.e., 420 of the 645 fishes were of the three 

noted species). Eight species were represented by five or fewer specimens (e.g., rare species). Similarly, 

Jarvela and Thorsteinson (1999) sampled epipelagic fishes in coastal waters of the Alaskan Beaufort Sea in 

1988, 1990, and 1991. The most abundant marine fishes in the catches were arctic cod (16.4-87.4% of total 

catch between years), capelin (5.3-81.5% of total catch between years), and snailfishes (0.3-3.0% of total 

catches between years). Many species caught registered only as trace amounts of <0.1% of the catch. 

Species having low abundance and/or small ranges occurring in the first quartile of the frequency 

distribution of species abundances or range sizes (i.e., 25%; the quartile definition from Gaston, 1994) are 

termed “rare” (Gaston, 1994). Rare species are regarded as those having low abundance and/or small 

ranges (Gaston, 1994) occurring in the first quartile of the frequency distribution of species abundances or 

range sizes (i.e., 25%; the quartile definition from Gaston, 1994). The terms “common” and “widespread” 

are used as an antithesis of “rare” (Gaston, 1994). Abundance terms were not defined in most of the 

literature; one document describes a diadromous species as “rare” for which they cite approximately 100 

specimens were collected, relative to another document reporting a marine species as “rare” for which five 

or less specimens were collected. Such disparities between documents may, in part, be due to sampling 

effort or the scope of the individual report, all of which must be considered when synthesizing the 

information as a baseline from which to assess impacts as significant or not. Rare as used in this sense does 

not imply protected status under the law, such as under the Endangered Species Act. 

III.F.1.d. Pacific Salmon and Essential Fish Habitat. All five species of Pacific salmon occur in the 

Alaskan Beaufort and Chukchi seas (Craig and Halderson, 1986; NMFS, 2005); they are the pink 

(humpback), chum (dog), sockeye (red) salmon, chinook (king) salmon, and coho (silver) salmon. These 

five species of salmon are managed species for which EFH is described that includes areas in the Beaufort 

and Chukchi seas. Pacific salmon in the Alaskan Beaufort and Chukchi seas are considered “rare” species 

in terms of abundance and range as defined above in Section III.F.1.c. 

A significant body of information exists on the life histories and general distribution of salmon in Alaska 

(NMFS, 2005). Life history, general distribution, fisheries background, relevant trophic information, 

habitat, and biological associations are described for Pacific salmon in Appendix F.5 of NMFS (2005) and 

incorporated herein by reference. More information regarding the biology, ecology, and behavior of 

 PEA-42 
Pacific salmon is described in: Augerot (2005), Quinn (2005), and the ADF&G Fish Distribution 

Database-Fish Profiles (http://www.sf.adfg.state.ak.us/SARR/FishDistrib/FDD_fishprofiles.cfm). 

Salmon numbers decrease north of the Bering Strait, and they are relatively rare in the Beaufort Sea (Craig 

and Halderson, 1986). Spawning runs in arctic streams are minor compared to those of commercially 

important populations farther south (Craig and Halderson, 1986). Rivers south of Point Hope support 

comparatively large runs of chum and pink salmon, and have been basically the northern distributional 

limits for chinook, coho, and sockeye salmon (Craig and Halderson, 1986), although this appears no longer 

so. Craig and Halderson (1986) noted that only pink salmon and, to a lesser degree, chum salmon, occur 

with any regularity in arctic waters north of Point Hope and presumably maintain small populations in 

several of the northern drainages; most occurring in streams west of Barrow. 

In general, information on Pacific Salmon and their EFH is limited with respect to current distribution and 

abundance estimates and associated trends, local and regional movements; and specifics about life history 

habitats. See Section III.F.d(4) for a description of EFH for Pacific salmon in Alaska. 

III.F.1.d(1) Chinook, Sockeye, and Coho Salmon. There are no known stocks of chinook, sockeye, or 

coho salmon in arctic waters north of Point Hope (Craig and Halderson, 1986). All three species are 

considered extremely rare in the Beaufort Sea, representing no more than isolated migrants (vagrants) from 

populations in southern Alaska or Russia (Fechhelm and Griffiths, 2001). Records of these species usually 

consist of single specimens. Climate change in arctic Alaska (i.e., warming) may facilitate the range 

expansion of chinook, sockeye, and coho salmon (e.g., Babaluk et al., 2000). 

The northernmost known spawning population of Chinook salmon is believed to be in Kotzebue Sound 

(Healy 1991). Small numbers of Chinook salmon reportedly are taken each year in the Barrow domestic 

fishery, which operates in Elson Lagoon (Fechhelm and Griffiths, 2001, citing George, pers. commun.). 

Strays have been captured in the Kuk and Colville rivers (Craig and Halderson, 1986). There also are 

indications of a small run of Chinook salmon in the Kugrua River southwest of Point Barrow at Peard Bay 

in the Chukchi Sea (Fechhelm and Griffiths, 2001, citing George, pers. comm.). 

Sockeye salmon have their northernmost known spawning population in Kotzebue Sound (Stephenson, 

2006, citing Burgner, 1991). The northernmost known population of spawning coho salmon is near Point 

Hope, although coho salmon have occasionally been captured in marine waters farther east, near Prudhoe 

Bay (Craig and Halderson, 1986). 

III.F.1.d(2) Pink Salmon. Pink salmon are widely distributed over the northern Pacific Ocean and Bering 

Sea; they also occur to a lesser degree in arctic waters (Augerot, 2005). Pink salmon are the most abundant 

salmon species in the Beaufort Sea, although their abundance is greatly reduced compared to waters in 

western and southern Alaska (Craig and Halderson, 1986; Fechhelm and Griffiths, 2001). Their abundance 

generally increases from east to west along the Alaskan Beaufort Sea coast. Fechhelm and Griffiths (2001) 

state that reports of pink salmon in Canada are rare, with the last reported occurrence being that of Dymond 

(1940, as cited by Fechhelm and Griffiths, 2001). However, Babaluk et al. (2000) report the two most 

recent records of range extensions of pink salmon in the Canadian Arctic: pink salmon caught in August 

1993 in the Sachs River estuary subsistence fishery (Banks Island, Northwest Territories), and another 

caught in September 1992 in the West Channel of the Mackenzie River near Aklavik, Northwest 

Territories. Augerot (2005) depicts pink salmon of limited spawning distribution in the Alaskan Arctic. 

Craig and Halderson (1986) note that available data suggest that pink salmon are more abundant in evennumbered years (for example, 1978, 1982) than in odd-numbered years (for example, 1975, 1983), as is the 

general pattern for this species in western Alaska (Craig and Halderson, 1986, citing Heard, 1986). This 

perceived pattern may be a manifestation of the distinctive 2-year life cycle of the pink salmon. Unlike 

other anadromous fish species in arctic Alaska, the pink salmon is a short-lived species that places all its 

reproductive effort into a single spawning event, and then dies. With its rigid 2-year life cycle, there is 

virtually no reproductive overlap between generations; therefore, every spawning event must be successful 

for the continued survival of the stock (Craig and Halderson, 1986). 

 PEA-43 
Small runs of pink salmon sometimes occur in nine drainages north of Point Hope (Craig and Halderson, 

1986; Fechhelm and Griffiths, 2001). Small spawning runs of pink salmon occur in the Sagavanirktok and 

Colville rivers, although not predictably from year to year. Among the few pink salmon collected in the 

Sagavanirktok River and delta were several spawned-out adults. Bendock (1979) noted pink salmon 

spawning near the Itkillik River and at Umiat. Two male spawners were caught near Ocean Point just north 

of Nuiqsut (Fechhelm and Griffiths, 2001, citing McElderry and Craig, 1981). In recent years, “substantial 

numbers” of pink salmon have been taken near the Itkillik River as part of a fall subsistence fishery 

(Fechhelm and Griffiths, 2001, citing George, pers. commun.). Pink salmon also are taken in the 

subsistence fisheries operating in the Chipp River and Elson Lagoon just to the east of Point Barrow 

(Fechhelm and Griffiths, 2001, citing George, pers. commun.). Craig and Halderson (1986) proposed that 

pink salmon spawn successfully and maintain small but viable populations in at least some arctic drainages; 

continued occurrences of pink salmon in arctic drainages indicates their suggestion is credible. 

Run timings are rather inexact. Along the northeastern Chukchi Sea coast, run times in spawning streams 

may occur in mid-July; while along the western Beaufort coast, run times appear to commence in late July 

until the end of August (Craig and Halderson, 1986). Occurrence of adult salmon in spawning streams in 

mid- to late July indicates their presence in marine waters along the Arctic coast in advance of the runs. 

How early salmon move into marine waters of the region is unknown, but is hypothesized to precede runs 

in spawning streams by as much as several weeks. 

Schmidt, McMillan, and Gallaway (1983) describe the life cycle of pink salmon: 

Eggs are laid in redds [nests] dug in gravel. The eggs hatch during the winter however the alevins 

remain in the gravel, until the yolk sac is absorbed, emerging later in spring. After emerging from 

the gravel, the fry begin moving downstream. They remain in the estuary for up to a month prior 

to moving offshore. Little is known of the movements undertaken during the 18 months the 

salmon spend at sea. It is likely the North Slope populations move westerly towards the Chukchi 

Sea and upon maturing at the age of 2 years, the salmon then return to their natal streams to spawn 

in the fall. 

Generally, early marine schools of pink salmon fry, often in large, dense aggregations, tend to follow 

shorelines and, during the first weeks at sea, spend much of their time in shallow water only a few 

centimeters deep (NMFS, 2005:Appendix F). It has been suggested that this onshore period involves a 

distinct ecological life-history stage in both pink and chum salmon. In many areas throughout their ranges, 

pink salmon and chum salmon fry of similar age and size co-mingle in both large and small schools during 

early life in the marine environment. 

Diet studies show that pink salmon are both opportunistic and generalized feeders and on occasion they 

specialize in specific prey items (NMFS, 2005:Appendix F). Young-of-the-year probably do not feed 

significantly during the short period spent in natal streams but feed on copepods and other zooplankton in 

the estuary (Schmidt, McMillan, and Gallaway, 1983). As the fish grow, larger prey species become 

important, including amphipods, euphausiids, and fishes (Schmidt, McMillan, and Gallaway, 1983, citing 

Morrow, 1980 and Scott and Crossman, 1973). Craig and Halderson (1986) state that most (adult) pink 

salmon caught in Simpson Lagoon had not fed recently (88% empty stomachs, n=17). The only available 

information on marine feeding is from Kasegaluk Lagoon, where stomachs of 17 captured adult salmon 

contained mostly fish (chiefly arctic cod), with some amphipods and mysids (Craig and Halderson, 1986, 

citing Craig and Schmidt, 1985). Studies indicate that juvenile pink salmon are primarily diurnal feeders 

(NMFS, 2005:Appendix F). 

III.F.1.d(3) Chum Salmon. Chum salmon are widely distributed in arctic waters but are relatively less 

common than pink salmon (Craig and Halderson, 1986; Babaluk et al., 2000; Fechhelm and Griffiths, 

2001). Only populations relatively small in number spawn north and east of the Noatak River, which enters 

the Chukchi Sea at Kotzebue, Alaska (NMFS, 2005:Appendix F). In general, chum salmon spawn in the 

lower reaches of coastal streams <100 mi upstream from the ocean (NMFS, 2005:Appendix F). Chum 

salmon are the Pacific salmon most frequently caught by fishermen in the lower Mackenzie River area of 

Canada (Babaluk et al., 2000, citing Hunter, 1974). Their long migration up the Mackenzie River (about 

 PEA-44 
2,000 km) is nearly as impressive as that of chum salmon in the Yukon River (3,200 km [Craig and 

Halderson, 1986, citing Hart, 1973]). Despite the presence of these spawning stocks, few studies 

conducted in Canadian waters report catching chum salmon (Fechhelm and Griffiths, 2001). 

The Pitmigea, Kukpowruk, Kuk, and Kugrua rivers along the northeastern Chukchi Sea coast are reported 

to support small populations of chum salmon. Individual salmon have been collected in the Kukpuk, 

Kokolik, and Utukok rivers, Kuchiak Creek, Kaegaluk Lagoon, and along the Wainwright Coast; however, 

these salmon are treated as strays (Craig and Halderson, 1986; Fechhelm and Griffiths, 2001). 

Small spawning runs of chum salmon occur in the Colville River from mid-August to mid September 

(Bendock, 1979). In recent years, smolts have been caught in the lower delta (Fechhelm and Griffiths, 

2001, citing Moulton, 1999, 2001). Chum salmon are taken in the fall subsistence fishery but comprise a 

minor portion of the total catch (Fechhelm and Griffiths, 2001). Substantial numbers (undefined) of chum 

salmon are taken in the Chipp River and in Elson Lagoon, including adults in spawning condition, although 

such harvests are variable from year to year (Fechhelm and Griffiths, 2001, citing George, pers. commun.). 

Despite the presence of these runs, Fechhelm and Griffiths (2001) regard chum salmon as rare in Beaufort 

Sea coastal waters, particularly east of the Colville River. 

Generally, chum salmon return to spawn as 2-7-year olds (NMFS, 2005:Appendix F). Two-year-old chum 

are rare in North America and occur primarily in the southern part of their range (e.g., Oregon). Sevenyear-old chum also are rare and occur mostly in the northern areas (e.g., the Arctic). In general chum 

salmon get older from south to north. Slow to rapid growth in the ocean can modify the age at maturity. 

Slower growth during the second year at sea causes some chum salmon to mature 1 or 2 years later. 

Chum salmon fry, like pink salmon, do not overwinter in streams but migrate (mostly at night) out of 

streams directly to sea shortly after emergence. The timing of outmigration in the Arctic is unknown, but 

in more southern waters it occurs between February and June (chiefly during April and May). Chum 

salmon tend to linger and forage in intertidal areas at the head of bays. Estuaries are very important for 

chum salmon rearing during summer. 

Once in coastal waters, chum salmon juveniles probably migrate southward toward the Bering Sea, thereby 

avoiding the cold waters of the arctic marine environment in winter. There is apparently some evidence 

from a few tag recoveries that chum salmon from arctic rivers may migrate as far south as the Gulf of 

Alaska (Craig and Halderson, 1986, citing Neave, 1964). 

Juvenile chum salmon use a wide variety of prey species, including mostly invertebrates (including 

insects), and gelatinous organisms (NMFS, 2005:Appendix F). Chum salmon eat a variety of foods during 

their ocean life, e.g., amphipods, euphausiids, pteropods, copepods, fish, and squid larvae. Chum salmon 

also use gelatinous zooplankton for food more often than other species of salmon. 

Chum salmon are subject to the same habitat concerns as other species of salmon, e.g., habitat destruction, 

pollution (NMFS, 2005:Appendix F). Additionally, chum salmon have two habitat requirements that are 

essential in their life history that make them very vulnerable: (1) reliance on upwelling ground water for 

spawning and incubation and (2) reliance on estuaries/tidal wetlands for juvenile rearing after migrating out 

of spawning streams. In the Noatak River, an arctic drainage just south of Point Hope, chum salmon spawn 

in areas where intragravel temperatures are 3-5 °C higher than in the mainstem (Craig and Halderson, 1986, 

citing Merritt and Raymond, 1983). These warmer spawning habitats provide about 1,130 temperature 

units (centigrade-degree days) between spawning and emergence, compared to only 215 temperature units 

available elsewhere in the drainage during the same period (Craig and Halderson, 1986). The hydrology of 

upwelling ground water into stream gravel is highly complex and poorly understood (NMFS, 

2005:Appendix F). 

III.F.1.d(4) Essential Fish Habitat for Pacific Salmon in Alaska. Essential Fish Habitat for each Pacific 

salmon species is described and mapped by NMFS (2005). The Alaska Department of Fish and Game 

maintains anadromous waters data in its Fish Distribution Database 

(http://www.sf.adfg.state.ak.us/sarr/FishDistrib/anadcat.cfm) and interactive mapping. More than 14,000 

 PEA-45 
waterbodies containing anadromous salmonids identified in the State represent only part of the salmon EFH 

in Alaska, because many likely habitats have not been surveyed. Marine EFH for the salmon fisheries in 

Alaska includes all estuarine and marine areas used by Pacific salmon of Alaska origin, extending from the 

influence of tidewater and tidally submerged habitats to the limits of the U.S. Exclusive Economic Zone 

(EEZ). This habitat includes waters of the continental shelf (to the 200-m isobath). In the deeper waters of 

the continental slope and ocean basin, salmon occupy the upper water column, generally from the surface 

to a depth of about 50 m. Chinook and chum salmon use deeper layers, generally to about 300 m, but on 

occasion to 500 m. The marine EFH for Alaska salmon fisheries described above also is EFH for the 

Pacific coast salmon fishery for those salmon stocks of Pacific Northwest origin that migrate through 

Canadian waters into the Alaska EFH zone. A more detailed description of EFH for salmon found in 

Arctic Alaska includes: 

• Estuarine EFH for juvenile chinook salmon is the general distribution area for this lifestage, 

located in estuarine areas, as identified by the salinity transition zone (ecotone) and the mean 

higher tide line, within nearshore waters. Chinook salmon smolts and postsmolt juveniles may be 

present in these estuarine habitats from April through September (NMFS, 2005:Figures D-177 

through D-182). Marine EFH for juvenile Chinook salmon is the general distribution area for this 

lifestage, located in all marine waters off the coast of Alaska from the mean higher tide line to the 

200-nmi limit of the EEZ, including the Gulf of Alaska, eastern Bering Sea, Chukchi Sea, and 

Arctic Ocean. Juvenile marine chinook salmon are at this life stage from April until annulus 

formation in January or February during their first winter at sea (NMFS, 2005:Figure D-183). The 

EFH for immature and maturing adult Chinook salmon is the general distribution area for this 

lifestage, located in marine waters off the coast of Alaska and ranging from the mean higher tide 

line to the 200-nmi limit of the U.S. EEZ, including the Gulf of Alaska, eastern Bering Sea, 

Chukchi Sea, and Arctic Ocean (NMFS, 2005:Figure D-183). 

• Estuarine EFH for juvenile sockeye salmon is the general distribution area for this lifestage, 

located in estuarine areas, as identified by the salinity transition zone (ecotone) and the mean 

higher tide line, within nearshore waters. Under-yearling, yearling, and older smolts occupy 

estuaries from March through early August, as depicted in Figures D-170 through D-175 (NMFS, 

2005). Marine EFH for juvenile sockeye salmon is the general distribution area for this lifestage, 

located in all marine waters off the coast of Alaska to depths of 50 m and range from the mean 

higher tide line to the 200-nmi limit of the U.S. EEZ, including the Gulf of Alaska, eastern Bering 

Sea, Chukchi Sea, and Arctic Ocean from midsummer until December of their first year at sea, as 

depicted in Figure D-176 (NMFS, 2005). The EFH for immature and maturing adult sockeye 

salmon is the general distribution area for this lifestage, located in marine waters off the coast of 

Alaska to depths of 200 m and range from the mean higher tide line to the 200-nmi limit of the 

U.S. EEZ, including the GOA, EBS, Chukchi Sea, and Arctic Ocean, as depicted in Figure D-176 

(NMFS, 2005). 

• Estuarine EFH for juvenile coho salmon is the general distribution area for this lifestage, located 

in estuarine areas, as identified by the salinity transition zone (ecotone) and the mean higher tide 

line, within nearshore waters. Juvenile coho salmon require year-round rearing habitat and also 

migration habitat from April to November to provide access to and from the estuary. Marine EFH 

for juvenile coho salmon is the general distribution area for this lifestage, located in all marine 

waters off the coast of Alaska from the mean higher tide line to the 200-nmi limit of the U.S. EEZ, 

including the Gulf of Alaska, eastern Bering Sea, Chukchi Sea, and Arctic Ocean, as depicted in 

Figure D-190 (NMFS, 2005). The EFH for immature and maturing adult coho salmon is the 

general distribution area for this lifestage, located in marine waters off the coast of Alaska to 200 

m in depth and range from the mean higher tide line to the 200-nmi limit of the U.S. EEZ, 

including the GOA, EBS, Chukchi Sea, and Arctic Ocean, as depicted in Figure D-190 (NMFS, 

2005). 

• Estuarine EFH for juvenile pink salmon is the general distribution area for this lifestage, located in 

estuarine areas, as identified by the salinity transition zone (ecotone) and the mean higher tide line, 

within nearshore waters and generally present from late April through June, as depicted in Figures 

D-156 through D-161 (NMFS 2005). Marine EFH for juvenile pink salmon is the general 

distribution area for this life stage, located in all marine waters off the coast of Alaska from the 

mean higher tide line to the 200-nmi limit of the U.S. EEZ, including the Gulf of Alaska, eastern 

 PEA-46 
Bering Sea, Chukchi Sea, and Arctic Ocean, as depicted in Figure D-162 (NMFS 2005). The EFH 

for immature and maturing adult pink salmon is the general distribution area for this lifestage, 

located in marine waters off the coast of Alaska to depths of 200 m and range from the mean 

higher tide line to the 200-nmi limit of the U.S. EEZ, including the Gulf of Alaska, eastern Bering 

Sea, Chukchi Sea, and Arctic Ocean. Mature adult pink salmon frequently spawn in intertidal 

areas and are know to associate with smaller coastal streams, as depicted in Figure D-162 (NMFS 

2005). 

• Estuarine EFH for juvenile chum salmon is the general distribution area for this lifestage, located 

in estuarine areas, as identified by the salinity transition zone (ecotone) and the mean higher tide 

line, within nearshore waters from late April through June, as depicted in Figures D-163 through 

D-168 (NMFS, 2005). Marine EFH for juvenile chum salmon is the general distribution area for 

this lifestage, located in all marine waters off the coast of Alaska to approximately 50 m in depth 

from the mean higher tide line to the 200-nmi limit of the EEZ, including the Gulf of Alaska, 

eastern Bering Sea, Chukchi Sea, and Arctic Ocean, as depicted in Figure D-169 (NMFS, 2005). 

The EFH for immature and maturing adult chum salmon is the general distribution area for this 

lifestage, located in marine waters off the coast of Alaska to depths of 200 m and ranging from the 

mean higher tide line to the 200-nmi limit of the EEZ, including the Gulf of Alaska, eastern 

Bering Sea, Chukchi Sea, and Arctic Ocean, as depicted in Figure D-169 (NMFS, 2005). 

III.F.1.d(5) Distribution and Abundance Trends of Pacific Salmon in the Alaskan Beaufort Sea. The 

literature largely treats the Beaufort Sea as a population sink for Pacific salmon, in some cases suggesting 

that none of the salmon species have established sustained populations in waters east of Point Barrow 

(Bendock and Burr, 1984). Many reports describe salmon as “straying” into the Beaufort Sea (Craig and 

Halderson, 1986) or comprising only a few isolated spawning stocks of pink and chum salmon (Craig and 

Halderson, 1986; Fechhelm and Griffiths, 2001). The occurrence of pink and chum salmon in arctic waters 

probably is due to their relative tolerance of cold water temperatures and their predominantly marine life 

cycle (Craig and Halderson, 1986, citing Salonius, 1973). The expansion of chinook, sockeye, and coho 

salmon into the Arctic appears restricted by cold water temperatures, particularly in freshwater 

environments (Craig and Halderson, 1986). However, the recent range extensions of pink, sockeye, and 

chum salmon in the Canadian Arctic, as described by Babaluk et al. (2000), indicate that some Pacific 

salmon may be expanding their distribution in arctic waters, and possibly their abundance as well. Babaluk 

et al. (2000) also note that significant temperature increases in arctic areas as a result of climate warming 

may result in greater numbers of Pacific salmon in the area. 

Because Pacific salmon appear to be expanding their range eastward and northward in the Canadian 

Beaufort Sea, it is reasonable to expect that Pacific salmon are expanding their distribution in the Chukchi 

Sea and that their populations may be increasing in both the northeastern Chukchi Sea and western 

Beaufort Sea. 

III.F.1.e. Invertebrate Fishery Resources and Fragile Biocenoses. Recall that the MSA defines “fish” 

to mean finfish, mollusks, crustaceans, and all other forms of marine animal and plant life other than 

marine mammals and birds. The term “fishery resource” means any fishery, any stock of fish, any species 

of fish, and any habitat of fish. In the western Beaufort and northeastern Chukchi seas, there are several 

additional forms of marine animal and plants that are important fishery resources. These forms include 

macroscopic algae (chiefly kelp communities forming biogenic structures), squid, and snow crab. 

III.F.1.e(1) Kelp and Macroscopic Algae. Dense kelp grows on a few areas of the seabed of the Beaufort 

Sea (USDOI, MMS, 2003a). The distribution of kelp is limited by three chief factors: ice gouging, 

sunlight, and hard substrate. Ice gouging restricts the growth of kelp to protected areas, such as behind 

barrier islands and shoals. Hard substrates are necessary for kelp to hold fast and are restricted to areas 

with low sedimentation rates. The best known kelp bed in the Beaufort Sea is the Boulder Patch. It is 

located behind the barrier islands of Stefansson Sound (USDOI, MMS, 2002). Kelp also grows sparsely in 

West Camden Bay (USDOI, MMS, 1998). 

The Boulder Patch is well studied and supports about 300 known infaunal and epilithic species (Dunton 

and Schonberg, 2000). The total biomass of organisms is about an order of magnitude higher than for most 

 PEA-47 
of the OCS seabed; in contrast to the 30 grams per square meter (g/m2

) of benthos of most of the Beaufort 

OCS seabed, about 300 g/m2

 of epilithic organisms inhabit the Boulder Patch (Dunton and Schonberg, 

2000). The kelp community spreads very slowly, taking almost a decade to recolonize denuded boulders 

(Martin and Gallaway, 1994). The plants live a long time; Dunton observed some that probably were more 

than 40 years old and noted that growth of kelp in the Boulder Patch has varied considerably from year to 

year (USDOI, MMS, 1998). 

Distribution and density of kelp in western Camden Bay is not well known (USDOI, MMS, 2003a). 

During exploration of the Warthog Prospect in 1997, kelp was observed on a patch of boulders in about 11 

m of water (USDOI, MMS, 1998). Kelp also has been observed shoreward in an area behind a shoal near 

Konganevik Point, although its spatial distribution and density are not known. 

Kelp beds are likely to occur elsewhere in the western Beaufort Sea but have not been systematically 

surveyed, and other kelp beds may be discovered as more areas are explored. Systematic surveys of 

macroscopic algae, especially kelp beds, have not been conducted in the northeastern Chukchi Sea. 

Records from a variety of sources do indicate the presence of at least two kelp beds along the coast. One 

first described by Mohr, Wilimovsky, and Dawson (1957) and confirmed by Phillips et al. (1982) is located 

about 20 km northeast of Peard Bay near Skull Cliff. Another was reported by Phillips and Reiss (1985) 

approximately 25 km southwest of Wainwright in water depths of 11-13 m. The known kelp beds are 

located relatively close to the coast in State waters. 

Macroscopic algal growth in nearshore areas of the Chukchi Sea probably is limited by the availability of 

suitable substrates (rock, cobble, and gravel) (USDOI, MMS, 1990a). The existent kelp beds and stand of 

green sea lettuce (Ulva) in Peard Bay are additional sources of primary production. Kelp beds provide 

three-dimensional structure in an otherwise homogeneous environment that, in some areas, increases the 

diversity of organisms living in the area. Mohr, Wilimovsky, and Dawson (1957) recorded that relatively 

few invertebrates (all polychaetous annelids and arthropods) were taken, as well as six species of fishes in 

association with the algae near Skull Cliff. 

III.F.1.e(2) Squid and Essential Fish Habitat. Squid occur in the northeastern Chukchi and western 

Beaufort seas; as squid on occasion (e.g., in 1998 and 2005) strand on the beach near Barrow (George, 

2005, pers. commun.). In general, squid can be among the more dominant prey species for some marine 

fishes, seabirds, and marine mammals. No information was found as to the species inhabiting the areas; 

hence, we cannot describe their biology and ecology as relating to a baseline description. 

III.F.1.e(3) Snow crab (Chionoecetes opilo) and Essential Fish Habitat. The snow crab is a circumpolar 

species for which there are substantial fisheries in the Atlantic and Pacific oceans (Paul, Paul, and Barber, 

1997). In the northwest Pacific Ocean, snow crabs occur in the northern Sea of Japan, the Bering and 

Chukchi seas from Wrangel Island to Point Barrow, and the Beaufort Sea at the mouth of the Mackenzie 

River (Paul, Paul, and Barber, 1997, citing Slizkin 1989). In the northeastern Chukchi Sea, snow crabs are 

a dominant benthic species; however, because they have not been historically harvested their basic biology 

and ecology is poorly described. 

The snow crab is a brachyuran (meaning short-tailed) or true crab. The body is composed mainly of a 

chitinous shell or carapace with a small abdominal flap. They have five pairs of legs, with the first pair 

equipped with pincers. Snow crabs may live to an estimated maximum age of 14 years 

(http://www.adfg.state.ak.us/pubs/notebook/shellfsh/tanner.php). 

Females mate with an adult male for the first time during her last molt (maturity molt). The male crab is 

attracted by a chemical attractant (pheromone) released by the female. Females molt to sexual maturity and 

mate in the softshell condition while grasped by the male. Older, hard-shelled females also are mated by 

adult males but in the absence of a male, they are capable of producing an egg clutch with sperm stored 

from a previous mating. 

Fertilization is internal, and the eggs usually are ovulated (extruded) within 48 hours onto the female’s 

abdominal flap, where they incubate for a year. Hatching occurs late the following winter and spring, with 

 PEA-48 
the peak hatching period usually during April to June. This is normally the peak of the spring plankton 

bloom, so egg hatch coincides with the high availability of food for the larvae crab. 

The young, free-swimming larvae molt many times and grow through several distinct stages. Growth 

during this period usually is dependent on water temperature but lasts about 63-66 days, after which the 

larvae lose their swimming ability and settle to the ocean bottom. After numerous molts and several years 

of growth, females mature at approximately 5 years of age. Males mature at about 6 years. 

Recent research by Dionne et al. (2003) determined the distribution pattern of juvenile snow crab in the 

northwestern Gulf of St. Lawrence, Canada. They found that juvenile snow crabs had a heterogeneous 

distribution among the temperature-depth strata and expressed specific habitat preferences, both ontogeny 

dependent. Temperature seemed to be more important than substratum for determining the spatial 

distribution of juvenile snow crabs. They also observed a shift in juvenile distribution towards shallower 

depths with increasing age, and suggested the ontogenic shift in juvenile distribution may reflect either high 

mortality in deep strata or migration to shallow waters. Such habitat shifts with ontogeny are common 

among mobile marine animals. They suggested that warmer surface temperatures could increase growth 

for older juvenile stages of snow crabs, as documented in other species of crabs. 

Snow crabs feed on a wide assortment of marine life including worms, clams, mussels, snails, crabs, other 

crustaceans, and fish parts. They are fed on by demersal and pelagic fish, and humans. Migration patterns 

are not well understood. It is known that the sexes are separated during much of the year and move into the 

same areas during the reproductive season. 

Paul, Paul, and Barber (1997) noted that little is known about the factors influencing the distribution and 

abundance of snow crabs, and that such factors must include larval recruitment dynamics, habitat 

requirements, thermal tolerance, water-depth preferences, predation, competition, and cannibalism, and that 

the relative importance of these factors is unknown. Theirs is the most recent study of snow crabs in the 

Chukchi Sea. Paul, Paul, and Barber, (1997) sampled 56 stations in the northeastern Chukchi Sea 

during1990-1991 and found snow crabs present at all stations, with the largest abundance and biomass 

tending to be in the southern part (south of 70° N. latitude to Point Hope) of their study area, but varying 

extensively between stations. Abundance and biomass estimates also varied considerably between trawls at 

most stations. The highest estimated mean abundance (100,000/km2

) was at station 1 (i.e., northwesternmost station sampled); the lowest mean abundance (190/km2

) was at station 28 (i.e., approximately 22 nmi 

southwest of Hanna Shoal). Mature crabs of both sexes were collected in the Chukchi Sea during their 

study. Paul, Paul, and Barber (1997) found that Chukchi snow crab tended to be smaller than Bering Sea or 

North Atlantic individuals. They also found that fecundity estimates for Chukchi snow crab are similar to 

other estimates. Fecundity of snow crabs positively correlated to increasing body size (Paul, Paul, and 

Barber, 1997, citing Haynes et al., 1981; Paul and Fuji, 1989). Paul, Paul, and Barber (1997) noted that 

contrasting observations with those of Jewett (1981, as cited by Paul, Paul, and Barber, 1997) suggest that 

the dates that snow crabs ovulate varies interannually. 

Prior to the survey conducted by Paul, Paul, and Barber (1997), Frost and Lowry (1983) caught 49 snow 

crabs in eight trawls (of a total of 35 successful tows) made in the western Beaufort Sea and northeastern 

Chukchi Sea. All snow crabs were caught west of 155 ̊ W. longitude. Only one female caught was bearing 

eggs. Frost and Lowry (1983) cited MacGinitie (1955) as reportedly catching no egg-bearing females off 

Point Barrow. The ratio of males to females collected by Frost and Lowry (1983) was about 2:1. 

III.F.1.f. Commercial Fisheries. While there are extensive fisheries off Alaska south of the Seward 

Peninsula and eastward toward the eastern Pacific Coast, there is little fishery activity beyond that of the 

subsistence fisheries in the Alaskan Arctic. In the Chukchi Sea, a small commercial fishery for Pacific 

salmon originates from Kotzebue, Alaska, and a smaller commercial fishery for snow crab in Federal 

waters appears to be growing. A family-operated commercial fishery (the Helmericks) exists in the 

Alaskan Beaufort. 

III.F.1.g. Past and Present Response to Climate Change. Fish resources of the northeastern Chukchi 

Sea were last surveyed 15-17 years ago. Additionally, other surveys over the years and area reflect a 

 PEA-49 
pattern of temporally and spatially irregular and disjunct sampling. Such disorganized sampling and data 

reporting greatly influences the information quality necessary to determine population trends and 

adjustments to environmental perturbations. Establishing a current, accurate, and precise baseline is critical 

to assessing potential changes to biotic resources. So, is the distribution and abundance information 

gathered by the last surveys still accurate and precise of arctic fish populations today? This is an important 

question, because the Chukchi and Bering seas are believed to be large marine ecosystems serving as 

principle bellwethers to climate change in North America and the Arctic Ocean. 

The climate of the Arctic is changing, and evidence of such change is discussed in Section III.A.1 as well 

as in the Arctic Climate Impact Assessment (ACIA, 2005). Trends in instrumental records over the past 50 

years indicate a reasonably coherent picture of recent environmental change in northern high latitudes 

(ACIA, 2005). It is probable that the past decade was warmer than any other in the period of the 

instrumental record. The observed warming in the Arctic appears to be without precedent since the early 

Holocene. 

Climate change is altering the distribution and abundance of marine life in the Arctic. For example, Berge 

et al. (2005) report the fist observations of settled blue mussels, Mytilus edulis, in the high Arctic 

Archipelago of Svalbard for the first time since the Viking Age. A scattered population was discovered at a 

single site at the mouth of Isfjorden in August 2004. Their data indicate that most mussels settled there as 

spat in 2002, and that larvae were transported by the currents northwards from the Norwegian coast to 

Svalbard the same year. This extension of the blue mussels’ distribution range was made possible by the 

unusually high northward mass transport of warm Atlantic water resulting in elevated sea-surface 

temperatures in the North Atlantic and along the west coast of Svalbard. Numerous other examples are 

being realized in the North Atlantic, where temperate and subtropical fishes are being caught and 

documented for the first time off the United Kingdom and the Scandinavian countries. 

While climatic warming is not distributed evenly across the Arctic, the Bering, Chukchi, and Beaufort seas 

are clearly experiencing a warming trend (ACIA, 2005). Over the last 50 years, annual average 

temperatures have risen by about 2-3  ̊C in Alaska and the Canadian Yukon, and by about 0.5  ̊C over the 

Bering Sea and most of Chukotka (ACIA, 2004). The largest changes have been during winter, when nearsurface air temperatures increased by about 3-5  ̊C over Alaska, the Canadian Yukon, and the Bering Sea, 

while winters in Chukotka got 1-2  ̊C colder.

Climate change can affect fish production (e.g., individuals and/or populations) through a variety of means 

(Loeng, 2005). Direct effects of temperature on the metabolism, growth, and distribution of fishes occur. 

Food-web effects also occur through changes in lower trophic-level production or in the abundance of 

predators, but such effects are difficult to predict. Fish-recruitment patterns are strongly influenced by 

oceanographic processes such as local wind patterns and mixing and by prey availability during early 

lifestages. Recruitment success sometimes is affected by changes in the time of spawning, fecundity rates, 

survival rate of larvae, and food availability. 

For example, a climate shift occurred in the Bering Sea in 1977, abruptly changing from a cool to a warm 

period—perhaps a reflection of the Pacific Decadal Oscillation (ACIA, 2004, 2005). The warming brought 

about ecosystem shifts that favored herring stocks and enhanced productivity for Pacific cod, skates, 

flatfish, and noncrustacean invertebrates. The species composition of seafloor organisms changed from 

being crab dominated to a more diverse assemblage of echinoderms, sponges, and other sea life. 

Historically high commercial catches of Pacific salmon occurred. The walleye pollock catch, which was at 

low levels in the 1960’s and 1970’s (2-6 million tonnes), has increased to levels >10 million tonnes for 

most years since 1980. Additional recent climate-related impacts observed in the Bering Sea large marine 

ecosystem include significant reductions in certain seabird and marine mammal populations, unusual algal 

blooms, abnormally high water temperatures, and low harvests of salmon on their return to spawning areas. 

While the Bering Sea fishery has become one of the world’s largest, numbers of salmon have been far 

below expected levels, fish have been smaller than average, and their traditional migratory patterns appear 

to have been altered. 

 PEA-50 
We know that better-known fish resources (e.g., abundant species) can exhibit very large interannual 

fluctuations in distribution, abundance, and biomass (e.g., capelin, arctic cod, Bering flounder, Pacific sand 

lance). Climate change experienced in the past and apparently accelerating in arctic Alaska likely is 

altering the distribution and abundance of their respective populations from what was known from past 

surveys. 

The Arctic Climate Impact Assessment (ACIA, 2004, 2005) concluded (in part) that: 

(1) The southern limit of distribution for colder water species (e.g., Arctic cod) are anticipated to 

move northward. The distribution of more southerly species (e.g., from the Bering Sea) are 

anticipated to move northward. Timing and location of spawning and feeding migrations are 

anticipated to alter; 

(2) Wind-driven advection patterns of larvae may be critical as well as a match/mismatch in the 

timing of zooplankton production and fish-larval production, thereby influencing productivity 

(e.g., population abundance and demography); 

(3) That species composition and diversity will change: Pacific cod, herring, walleye pollock, and 

some flatfish are likely to move northward and become more abundant, while capelin, Arctic cod, 

and Greenland halibut will have a restricted range and decline in abundance. 

III.F.1.h. Data Deficiencies. Information of current distribution and abundance (e.g., density/km2

) 

estimates, age structure, population trends, or habitat use areas are not available or are outdated for fish 

populations in the northeastern Chukchi or western Beaufort seas. It is not known if the findings of Frost 

and Lowry (1983) still accurately portray the diversity and abundance of demersal fishes in the Alaskan 

Beaufort Sea. Another important data gap is the lack of information concerning discrete populations for 

arctic fishes using modern scientific methods. In addition, Pacific salmon occur in the region; however, 

studies directed at investigating their population dynamics, migration, and habitat use are nonexistent. 

III.F.1.i. Potential Impacts of the Proposed Action. The principle impacting agent attributable to the 

Proposed Action involves the acoustic-energy pulses emitted by airguns used in the seismic surveys. 

Additional impacting agents involve vessel-traffic noise and anchoring and the introduction of hydrophone 

arrays towed or suspended in the ocean or placed on the seafloor. This section scrutinizes the acoustic 

impacts associated with airgun emissions and vessel noise and mechanical impacts to habitat (i.e., via 

anchoring, cable towing, deployment and retrieval from the seafloor, and cable hangups within fragile 

biocenoses). 

The MMS also assumes that marine resources could be exposed to accidentally spilled lubricating oil or 

diesel fuel from a vessel associated with seismic-survey operations or by a leaking or torn streamer array 

under tow by a vessel, if solid/gel streamers are not used. The liquid used to fill and provide streamer 

buoyancy usually is liquid paraffin that is biodegradable and evaporates very quickly. The MMS believes 

that the incidents involving the release of oil and fuel from vessels during refueling likely would be small, 

on the order of <5 gallons. This section also assesses potential impacts of such accidental spills on 

fish/fishery resources and EFH. 

III.F.1.i(1) Acoustic Detection and Capabilities. Marine organisms have evolved a plethora of ways to 

sense their environment and then use these senses to provide information that allows them to communicate 

and to find their way (Popper, 2003a). To the best of our knowledge, hearing by aquatic species is 

primarily confined to vertebrates, though there are many noisy aquatic invertebrates but little data on these 

animals in which to draw broad generalizations of their inability to hear (Popper, 2003a). 

Fishes can detect sounds via the saccule of the ear (one of the inner ear end organs) (Popper et al., 2003). 

Studies have demonstrated that many fish species produce and use sounds for a variety of behaviors with 

some discriminating between different frequencies and intensities and detect the presence of a sound within 

substantial background noise (Popper et al., 2003). Recent studies have shown that localization is indeed 

possible (Popper et al., 2003, citing e.g., Schuijf et al., 1972; Schuijf, 1975; Hawkins and Sand, 1977). Fish 

bioacoustics is an extensive topic that includes hair-cell-based systems (i.e., auditory system and lateralline system); theses concerning such include Tavolga et al. (1981); Popper and Fay (1993); Coombs and 

 PEA-51 
Montgomery (1999); Popper and Fay, (1999); Coombs and Braun (2003); Popper et al. (2003); and 

Nedwell et al. (2004), and are incorporated herein by reference. Also provided herein are some salient 

points from these references that are directly pertinent to the assessment of potential impacts. 

Hearing in fishes is not only for acoustic communication and detection of sound-emitting predators and 

prey but can also play a major role in telling fishes about the acoustic scene at distances well beyond the 

range of vision (Popper et al., 2003). For example, Crawford and Jorgenson (1993) suggested that the 

schooling behavior of arctic cod could be the result of their orienting their distribution under drifting pack 

ice according to the sound generated by floating ice pieces. Arctic cod have drumming muscles on their 

gas bladder (Crawford and Jorgenson, 1993, citing Hawkins and Rasmussen, 1978). They note that sound 

is an important orientation or communication stimulus to other arctic animals and suggest that it also may 

be important to arctic cod. 

Teleost (bony) fishes produce sound in several ways (Popper et al., 2003). These fishes use a variety of 

different methods to produce sounds that range from simply moving two bones together to more complex 

mechanisms involving exceptionally fast muscles connected to the swim bladder. The gas bladder in the 

abdominal cavity may serve as a sound amplifier (although it has other functions as well). Sounds 

produced in this way usually have most of their energy below 1,000 Hz and most often below 500 Hz. 

Fishes use sounds in behaviors including aggression, defense, territorial advertisement, courtship, and 

mating (Popper et al., 2003). Some marine catfish have been suggested to use a form of “echolocation” to 

identify objects in their environment by producing low-frequency sounds and listening to the reflections 

(Popper et al., 2003, citing Tavolga, 1971b, 1976a). 

The temporal pattern of fish sounds, rather than their frequency spectrum, has been considered the most 

important communicative feature of sounds generated by fishes (Popper et al., 2003, citing Winn, 1964). 

Popper et al. (2003, citing Myrberg and Riggio, 1985) demonstrated that bicolor damselfish, Stegastes 

partitus, can discriminate between individuals of the same species, and they speculated that the 

discrimination was based on frequency components of the sounds. 

Very little is actually known about acoustic communication in fishes, in part due to difficulties in studying 

underwater acoustic behavior (see Popper et al., 2003, citing Zelick et al., 1999 for a discussion of this 

issue). It is likely that many more fish species make and use sounds than currently reported in the 

literature. 

Popper and his coworkers recently argued that fishes are likely to use sound for more than interspecific 

communication (Popper et al., 2003, citing Sand and Karlsen, 1986, 2000; Popper and Fay, 1997; Fay and 

Popper, 2000). It is now widely thought that terrestrial vertebrates glean a good deal of information about 

the general nature of the environment from biological and nonbiological sounds making up the auditory 

scene (Popper et al., 2003, citing Bregman, 1990). From this concept, Popper et al. have suggested that 

vertebrate hearing evolved in aquatic ancestors of fishes as an adaptation to gain information about the 

environment in ways that were not obtainable by vision or the chemical senses, and especially about the 

environment beyond the range of these senses (Popper et al., 2003, citing Popper and Fay, 1997; Fay and 

Popper, 2000). It was only after hearing evolved that fishes are likely to have adapted the general soundprocessing capabilities for communication. Thus, while all fishes probably detect sounds and are likely to 

use sounds to learn about their environment, a smaller set of fishes actually have evolved use of sound for 

communication. 

Teleost fishes may be divided roughly into three nontaxomic groups, depending on their use of the swim 

bladder or other gas-filled structures as accessory hearing organs (Popper et al., 2003, citing Fay, 1988; 

Popper and Fay, 1999). The hearing specialists have either (1) a bony connection between the anterior part 

of the swim [gas] bladder and the inner ear or (2) gas-filled vesicles in close or direct contact with the inner 

ear otolith organs. Species lacking gas-filled structures constitute the other extreme, while fishes 

possessing a swim bladder but lacking specialized connections fall in between. The latter two groups are 

commonly termed hearing nonspecialists (or hearing generalists). The hearing specialists have both higher 

sensitivity in the optimal frequency range and higher upper-frequency cutoff than the other groups. For 

 PEA-52 
frequencies below 30-50 Hertz, hearing sensitivity probably converges in all groups. This convergence 

occurs because the free-field particle-motion oscillations will be exceeded by the pulsation amplitudes of a 

gas-filled bladder only above a certain frequency, which depends on both swim bladder volume and depth 

(Popper et al., 2003, citing Sand and Hawkins, 1973). Therefore, gas-filled bladders provide no auditory 

gain in the very low frequency range, where all species are insensitive to sound pressure. 

Sound pressure thresholds and audiograms can be interpreted only for the pressure-specialized species and 

have little or no meaning for unspecialized species (Popper et al., 2003). Nevertheless, it is often said that 

the sound pressure-hearing specialists hear with greater sensitivity and over a wider frequency range than 

hearing nonspecialists. For most sound sources (vibrating bodies) and under many environmental 

conditions, specialists will be able to detect the sound at lower source levels of motion or energy, at greater 

distances, and at higher frequencies than nonspecialists. Specialists detect lower source levels and a given 

source at greater distances because of the auditory gain provided by the swim bladder; and they have a 

higher frequency range of hearing than nonspecialists, because the underwater acoustic particle motions are 

smaller at the higher frequencies for a given sound-pressure level. 

Figure 1.4 from Popper et al. (2003) illustrates that hearing specialists detect sound pressure, with the 

lowest thresholds between 50 and 75 dB re 1 μPa and in the frequency range between about 100 and 2,000 

Hz. Pressure sensitivity generally declines at frequencies below 200-300 Hz and above 400-1,000 Hz. The 

most sensitive hearing (teleost fish) specialists have approximately the same sensitivity as the most 

sensitive mammals and birds (Popper et al., 2003, citing examples in Fay, 1988), when signal level at 

threshold is specified in units of acoustic intensity. The nonspecialists (including sharks) shown in Figure 

1.4 (i.e., thin lines) generally hear best below 500 Hz. 

Some teleost species can detect infrasound (sounds below 20 Hz). Studies have shown that a number of 

species are able to detect sounds substantially below 50 Hz in the infrasonic range (Popper et al., 2003, 

citing, e.g., Sand and Karlsen, 1986). 

Juvenile salmonids display strong avoidance reactions to infrasound (Popper et al., 2003, citing Knudsen et 

al., 1992, 1997), and it is reasonable to suggest that such behavior has evolved as a protection against 

predators. Infrasound has been used as an effective acoustic barrier for downstream migrating Atlantic 

salmon (Salmo salar) smolts (Popper et al., 2003, citing Knudsen et al., 1994). It has recently been shown 

that downstream migrating European silver eels (Anguilla anguilla) are deflected by intense infrasound 

fields (Popper et al., 2003, citing Sand et al., 2000). 

The acute sensitivity of at least some species of fishes to infrasound, or linear acceleration, may 

theoretically provide the animals with a wide range of information about the environment (e.g., detection of 

moving objects in the environment; courtship; predator-prey interactions). 

Recent behavioral investigations demonstrated that American shad (Alosa sapidissima) are able to detect 

high-intensity sounds from below 100 Hz to over 180 kHz, while goldfish, used as controls, were 

insensitive to ultrasound (Popper et al., 2003, citing Mann et al., 1997, 1998, 2001; Popper, 2000). The 

hearing range of the American shad overlaps with the range of echolocation sounds used by dolphins, a 

major shad predator. 

There probably is no other sensory system as specialized for sensory processing in the aquatic environment 

as the lateral line system (Coombs and Braun, 2003). It is a water-current detector found exclusively in 

aquatic fish and some amphibians. By its very nature, the lateral line system is generally a close-range 

system, capable of detecting current-generating sources (e.g., nearby swimming fishes) no more than one or 

two body lengths away. The lateral line system also can detect ambient water motions, such as those in a 

stream or ocean current, as well as distortions in ambient or self-generated motions due to the presence of 

stationary objects, such as rocks or boulders. As such, the lateral line system is believed to influence a 

number of different behaviors, including schooling, prey capture, courtship and spawning, and rheotaxis. 

In a more general sense, the lateral line system undoubtedly also is used to form hydrodynamic images of 

the environment, enabling fishes to determine the size, shape, identity, and location of both animate and 

inanimate entities in their immediate vicinity. 

 PEA-53 
It has generally been well appreciated that courtship and mating behaviors rely on multisensory 

information, particularly olfaction, vision, and hearing (Coombs and Braun, 2003). It also has been well 

known that fishes often incorporate courtship dances and vibratory motions in their mating and spawning 

rituals (Coombs and Braun, 2003, citing Tinbergen, 1951), yet the water motions created by these 

vibrations and movements have not received much attention as an information channel served by the lateral 

line system in coordinating reproduction (Coombs and Braun, 2003, citing Sargent et al., 1998). Satou and 

coworkers provided the first demonstration that vibratory motions are part of an information channel used 

to coordinate spawning in salmon (Coombs and Braun, 2003, citing Satou, 1987; Satou et al., 1987, 1991), 

and that this information channel is served by the lateral line system (Coombs and Braun, 2003, citing 

Sartou et al., 1997b). Further, successful coordination of spawning behaviors requires both visual and 

lateral line inputs (Coombs and Braun, 2003, citing Takeuchi et al., 1987; Satou et al., 1994a). These 

studies are the first to implicate the lateral line in communicative behaviors, but it is likely that this is a 

taxonomically more widespread function of the lateral line system and deserves further study. 

Evidence suggests that the lateral line serves as a pressure gradient and particle motion sensor enabling 

schooling fish to mediate their proximity and velocity within the body of their school (Stocker, 2002, citing 

Cahn, 1970; Partridge and Pitcher, 1980). Stocker (2002) suggests that a school of fish could be modeled 

as a low frequency oscillating body that the individual fish synchronize to. This view is supported by the 

visual presentation of fish schools in sunlight that sometimes appear to “flash” simultaneously as they 

respond to disturbances. This is substantiated also by evidence that when startled by airgun noise, 

schooling fish fall out of rank and take time to reassemble (Stocker, 2002, citing McCauley et al., 2000). 

The startle response involves establishing a tighter grouping, so the observed response is not believed a 

scatter response. The interruption or startle response observed in the airgun study might indicate that the 

hearing of individual fishes is momentarily compromised, or the pressure-gradient field of the school is 

disturbed sufficiently to lose its integrity and then takes time to reestablish, or perhaps some combination of 

both. 

Squid have demonstrated responses to sound (Stocker, 2002). This may have something to do with their 

schooling nature that requires synchronization with the school, and predator-aversion perception akin to 

that of schooling fishes (Stocker, 2002). Research on squid audition currently is scant. From the studies 

performed to date, we know that squid are adapted to particle- and pressure-gradient acoustic energy. 

While researchers noticed a predictable startle response at 174 dB (i.e., firing of ink sacks and avoidance 

behavior) from instantaneous impact noise, a ramped noise indicated a response threshold of 156 dB in a 

noticeable increase in alarm behavior-increase in swimming speed, and presumably shifts in metabolic 

rates (Stocker, 2002, citing McCauley et al., 2000). Squid response to ramped noise also includes their 

rising toward the surface where an acoustical shadow of 12 dB was observed. This indicates an annoyance 

sensitivity of perhaps 144 dB (Stocker, 2002). 

Cuttlefish and squid respond to water movements as low as 0.06 micrometers (Hanlon and Sashar, 2003, 

citing Budelmann and Bleckmann 1988), which is equivalent to the threshold of the hair cells in fish lateral 

lines (Hanlon and Sashar, 2003, citing Bleckmann et al., 1991). Biologically, this sensitivity means that 

cuttlefishes and squid are able to detect a moving fish of 1 m (1 yard [yd]) in body length from a distance 

of about 30 m (33 yd) (Hanlon and Sashar, 2003, citing Budelmann, 1994). It has been suggested that 

juvenile cuttlefishes used the lateral line to capture shrimp in total darkness, and it is conceivable that 

schooling squid might use the lateral line to maintain school structure (Hanlon and Sashar, 2003, citing 

Budelmann et al., 1991). 

Low-frequency hearing was demonstrated (Hanlon and Sashar, 2003, citing Packard et al., 1990) using 

classical conditioning to show that cuttlefishes, squid, and octopus respond behaviorally to frequencies of 

about 1-100 Hz. They did not test higher frequencies, so additional research is need on this subject. It is 

surmised that the statocyst organ may be the likeliest organ to sense these frequencies by detecting the 

particle motion rather than sound pressure (Hanlon and Sashar, 2003, citing Packard et al., 1990). 

 PEA-54 
III.F.1.i(2). Potential Impacts from Airgun Acoustic Emissions. A significant impact (as defined in 

Section II.E) to a fish/fishery resource or essential fish habitat is an adverse impact that results in a decline 

of abundance and/or change in distribution requiring three or more generations (or having an impact lasting 

10 or more years) for the indicated population to recover to its former status and one or more generations 

for rare fish resources. “Rare species” are regarded as those having low abundance and/or small ranges 

(Gaston, 1994). Their categorization of “rare” is not related to or indicative of any similar definitions used 

under the Endangered Species Act. Rather, the term “rare” used in this specific assessment simply refers to 

their low numbers or patchy distribution when compared with other more common or widespread fish 

species in the Proposed Action area. For example, restricted distribution of “rare” species may be due to 

habitat availability and preferences, extralimital occurrences of individuals of this species or even survey 

shortcomings but the overall population status of this species remains stable and sufficient. 

Anthropogenic noise in the marine environment is an issue of growing concern within the last 2 decades; as 

such, there are numerous reviews on effects associated with anthropogenic noise; mostly concerning 

marine mammals and less so concerning fish and invertebrates. Some relevant literature concerning 

anthropogenic noise and potential impacts on fish and invertebrates include: Banner and Hyatt, 1973; 

Blaxter, Gray, and Denton, 1981; Blaxter and Hoss, 1981; Hastings et al., 1996; Scholik and Yan, 2001; 

Popper, Webb, and Fay, 2002; Popper, 2003b; Stocker, 2002; Smith, Kane, and Popper, 2004a,b; Hastings 

and Popper, 2005; Wahlberg and Westerberg, 2005, and are incorporated by reference. Literature reviewed 

pertaining to seismic surveys and potential impacts on fish and invertebrates include Kostyuchenko, 1973; 

Dalen and Knutsen, 1987; Pearson, Skalski, and Malme, 1992; Pearson et al., 1994; Turnpenny and 

Nedwell, 1994; Wardle et al., 2001; Hassel et al., 2003, 2004; McCauley et al., 2000; McCauley, Fewtrell, 

and Popper, 2003; Canadian Department of Fisheries and Oceans (CDFO), 2004a,b; Popper et al., 2005, 

and are incorporated by reference. Details concerning airguns and their emissions relative to the acoustic 

environment are described in Sections II.A.4. and III.C. 

A summary of a review of this and additional literature provides the following information regarding 

potential impacts to marine fishes and invertebrates from seismic survey activity: 

• In general, marine fish likely can hear airgun sounds with seismic airgun emissions, especially for 

hearing generalists (e.g., flatfish) and specialists (e.g., herring). The frequency spectra of seismic 

survey devices cover the range of frequencies detected by most fish (Pearson, Skalski, and Malme, 

1992; Platt and Popper, 1981; Hawkins, 1981). Marine fish are likely to detect airgun emissions 

nearly 2.7-63 km (1.6-39 mi) from their source, depending on water depth (Pearson, Skalski, and 

Malme, 1992). Fish responses to seismic sources are species specific (Pearson, Skalski, and 

Malme, 1992). 

• Seismic-survey acoustic-energy sources may damage or kill eggs, larvae, and fry of some fishes 

occurring in close proximity to an airgun, but the harm is generally limited to within 5 m from the 

airgun and greatest within 1 m of the airgun (e.g., Kostyuchenko, 1973; Dalen and Knutsen, 1987; 

Holliday et al., 1986; Turnpenny and Nedwell, 1994). The magnitude of lethal and sublethal 

impacts to ichthyoplankton depend largely on the current patterns of ichthyoplankton distribution 

and densities and oceanographic conditions, in addition to the frequency by which an airgun array 

passes through patches of ichthyoplankton of varying densities. 

• Airguns are unlikely to cause immediate deaths of adult and juvenile marine fishes. Sound 

sources that have resulted in documented physiological damage and mortality of adult, juvenile, 

and larval fish have all been at or above 180 dB re 1 μPa (Turnpenny and Nedwell, 1994). 

• The likelihood of physical damage is related to the characteristics of the sound wave, the species 

involved, lifestage, distance from the airgun array, configuration of array, and the environmental 

conditions. 

• Damage from seismic emissions may develop slowly after exposure (Hastings et al., 1996). Table 

1 of Turnpenny and Nedwell (1994) lists observed injuries (for fishes: adult, juvenile, larvae, and 

eggs) caused by exposure to high-level sound sources. 

• Behavioral changes to marine fish and invertebrates from seismic survey activity have been noted 

in several studies (e.g., Dalen and Knusten, 1987; McCauley et al., 2000; McCauley, Fewtrell, and 

Popper, 2003; Pearson, Skalski, and Malme, 1992), including: balance problems (but recovery 

 PEA-55 
within minutes), disoriented swimming behavior, increased swimming speed, tightening schools, 

displacement, interruption of important biological behaviors (e.g., feeding, mating), shifts in the 

vertical distribution (either up or down), and occurrence of alarm and startle responses (generally 

around 180 dB re 1 μPa and above). 

• Thresholds for typical behavioral effects to fish from airgun sources occur within the 160-dB to 

200-dB range (Turnpenny and Nedwell (1994). Seismic operations likely will cause behavioral 

reactions in squid (e.g., inking or startle responses) at thresholds between 161-166 dB re 1 μPa 

(McCauley et al., 2000). 

• Two studies demonstrated that some pelagic or nomadic fishes leave the survey area during 

seismic surveys. The fish distribution in the area did not return to presurvey levels during the 5 

days after shooting had ceased. It is likely that fish behavior returns to normal at the cessation of 

seismic shooting, but the repopulation of the area is reliant upon a diffusionlike process (Table 

III.F.3) (Engas et al., 1996, 1993; Løkkeborg and Soldal, 1993). Other studies indicated the 

affected area may extend to 33 km from a survey operated in waters 50-300 m in depth, but this 

depends largely on the uncertain acoustic sensitivities of various arctic fish species. Some pelagic 

or nomadic fishes are expected to descend into the ensonified area, where they are likely to 

experience higher levels of airgun noise. Some sedentary, demersal fishes living near the bottom 

are likely to retreat to the bottom and remain in the survey area where they may be exposed to 

additional airgun emissions and experience sublethal effects (e.g., auditory impacts). 

• Effects of seismic operation on snow crabs found that surveys did not cause any acute or midterm 

mortality of crabs, embryos and locomotion of the resulting larvae after hatch were unaffected and 

gills, antennules, and statocysts (balance organs) were soiled but found to be completely cleaned 

of sediment when sampled 5 months later (CDFO, 2004a,b). 

The Canadian Department of Fisheries and Oceans reviewed scientific information on impacts of seismic 

sound on fish and concluded that exposure to seismic sound is considered unlikely to result in direct fish or 

invertebrate mortality (CDFO, 2004c). Other pertinent findings of this report include: 

• Field experiments on fish and invertebrates are lacking and make it difficult to evaluate the impact 

of a particular type of seismic sound, or more generally noise, on a particular species. No research 

has been undertaken to study disruption of communication, detection of predators/prey, navigation 

and other functionally uses of sound by fish. 

• There are no documented cases of fish or invertebrate mortality (as related to older life-history 

stages and not to eggs and larval lifestages) on exposure to seismic sound under field-operating 

conditions. 

• Under experimental conditions, sublethal and/or physiological effects, including effects on 

hearing, have sometimes been observed in fish exposed to an airgun [emissions]. Currently, 

information is inadequate to evaluate the likelihood of sublethal or physiological effects under 

field-operating conditions. The ecological significance of sublethal or physiological effects, were 

they to occur, could range from trivial to important depending on their nature. 

• Behavioral impacts to fish exposed to seismic sound are expected to be short term, with duration 

of effect less than or equal to the duration of exposure; to vary between species and individuals; 

and to be dependant on properties of received sound. The ecological significance of such effects 

is expected to be low, except where they influence reproductive activity. 

• The ecological significance of behavioral effects may be greater when influencing reproductive or 

growth (molting) activities or leading to a dispersion of spawning aggregations or deflection from 

migration paths. The magnitude of effect in these cases will depend on the biology of the species 

and the extent of the dispersion or deflection. 

• In general, the magnitude of mortality of eggs or larvae that models predict could result from 

exposure to seismic sound would be far below what would be expected to affect populations. 

Special life-history characteristics such as extreme patchiness in distribution and timing of key 

life-history events in relation to the duration and coverage of seismic surveys may require case-bycase assessment. 

 PEA-56 
• “Ramp up,” which is a gradual increase in decibel level as the seismic activities begin, can 

mitigate some adverse impacts to fish capable of detecting the noise and dispersing from disturbed 

areas before harm occurs. 

III.F.1.i(2)(a) Mortality and Physiological Damage. Overall, the available scientific and management 

literature suggests that mortality of juvenile and adult fish, the age-classes most relevant to future 

reproductive fitness and growth, would not likely result from seismic survey activity. Sound sources that 

have resulted in documented physiological damage and mortality of adult, juvenile, and larval fish have all 

been at or above 180 dB re 1 μPa (Turnpenny and Nedwell, 1994). Damage to hearing and tissues may 

occur to these age-classes if the animals are in close proximity to the seismic source (i.e., within 5 m); 

damage may not be reversed and apparent injuries to tissues involved with hearing may not develop 

immediately. Fishes with impaired hearing may have reduced fitness, potentially making them vulnerable 

to predators, possibly unable to locate prey or mates, sense their acoustic environment or, in the case of 

vocal fishes, unable to communicate with other fishes. Given that this most likely would occur to fish 

within very close proximity to the sound source and that mitigation measures in Section IV include a rampup requirement to provide fish with an opportunity to move away from the source (LGL, 2003), MMS 

anticipates any injury to adult and juvenile fish to be limited to a small number of animals. 

III.F.1.i(2)(b) Impacts to Behavior. The most likely impacts to marine fish and invertebrates from seismic 

activity would be behavioral disruptions. Behavioral impacts are most likely to occur in the 160-dB to 200-

dB range (Turnpenny and Nedwell, 1994). Seismic surveys using airguns may disturb and displace fishes 

and interrupt feeding, mating, or other behaviors, including: (1) shifts in the vertical (either up or down) or 

horizontal distribution (i.e., avoidance and displacement); (2) shifts in behavior (e.g., swimming direction 

or speed, changes in school formation and integrity, stunning, migration); and (3) the occurrence of alarm 

and startle responses (generally around 180 dB re 1 μPa and above). Specific responses are expected to be 

species specific. Displacement also may be relative to the biology and ecology of species involved. 

Available studies have indicated that these reactions are likely to be short-term in nature. Although 

repeated, short-term disturbances can result in long-term impacts, the activity under the Proposed Action is 

limited to the 2006 open-water season and the timeframe, therefore, is limited in scope. 

Fish distribution and feeding behavior can be affected by the sound emitted from airguns and airgun arrays 

(Turnpenny and Nedwell, 1994). Pelagic fish catch rates and local abundance were reduced within 33 km 

of the airgun array for at least 5 days after shooting (Engås et al., 1993, 1996). There is no conclusive 

evidence for long-term or permanent horizontal displacement, and vertical displacement may be the shortterm behavioral response (Slotte et al., 2003), It is likely in such a situation that fish behavior returns to 

normal at the cessation of seismic shooting but that the repopulation of the denuded area is reliant upon a 

diffusion-like process (Turnpenny and Nedwell, 1994). The persistence of behavioral effects has not been 

studied adequately (Turnpenny and Nedwell, 1994).. 

Seismic surveys potentially may disrupt feeding activity and displace diadromous and marine fishes (i.e., 

capelin, arctic cisco, and the whitefishes) from critical summer feeding areas along the Chukchi and 

Beaufort coasts. Summer is a period of intensive feeding activity in coastal waters. Feeding activity in 

capelin, for example, is highly seasonal. Feeding intensity increases in the prespawning season in late 

winter and early spring, but it declines with the onset of spawning migration. Feeding ceases altogether 

during spawning season. Survivors of spawning resume feeding several weeks postspawning and proceed 

at high intensity until early winter, when it ceases. Seismic surveys whose airgun emissions ensonify 

feeding areas where capelin forage preceding spawning migration may stimulate capelin to disperse to 

poorer foraging areas. An impact on prey consumption could limit available energy reserves for migration 

and spawning activity. It also may result in greater spawning mortality, thereby decreasing the parental 

cohorts’ ability to spawn again the following year. If seismic surveys disturbed foraging capelin postspawning, they potentially could deflect and displace to poorer foraging areas, which could adversely 

impact their survival into and over winter. Capelin whose foraging activity is adversely limited both preand postspawning are not likely to survive over the winter to spawn again the following year. While we 

cannot say with certainty the impacts of seismic surveys on fish feeding behavior, there is no present 

evidence that the behavioral impact of seismic surveys has a major effect on fish feeding, except perhaps in 

the immediate vicinity of an active survey vessel. 

 PEA-57 
III.F.1.i(2(c) Impacts to Migration, Spawning and Hatchling Survival. Most important to this issue are 

behavioral reactions that could result in disruption of migratory pathways or diminishing the availability of 

fish resources for subsistence resources (e.g., through fish abandoning important fishing grounds). For 

coastwise migratory fish species, acoustic disturbance may displace and disrupt important migratory 

patterns, habitat use, and life-history behaviors. The populations of many species move from one habitat to 

another and back again repeatedly during their life (Begon, Harper, and Townsend, 1990). The time-scale 

involved may be hours, days, months, or years. Many migrations ensure that during its life an individual 

passes backwards and forwards from one type of environment to another. The patches of the environment 

in which resources are available change with the changing seasons, and populations move from one type of 

patch in the environment to another. Migrations tend to ensure that animals always forage where foraging 

conditions are best; the animals move seasonally and escape the major changes in food supply and climate 

that they would meet if they stayed always in one area. Long-distance migrations, in virtually every case, 

seem to involve transit between areas where both supply abundant food but only for a limited period. They 

are areas in which seasons of comparative glut and famine alternate and which cannot support large 

resident populations year-round. Lifecycles tend also to be synchronized in time, so that the time of 

migration aggregates individuals at a precise season. Essentially, each organism is individually associated 

with a suitable habitat, and a population aggregated in this habitat is the consequence. 

For wide-ranging, migratory fish species, disturbance and displacement may disrupt important migratory 

and life-history behaviors and patterns or habitat areas. Seismic surveys (2D/3D marine streamer or oceanbottom-cable [OBC] surveys) conducted in Federal waters close to State waters, where many fishes migrate 

through to spawning sites along the coast or in anadromous streams of the Arctic, may disrupt or impede 

their migrations as fishes attempt to avoid airgun emissions. In addition, conducting more than one seismic 

operation simultaneously may influence the distribution of some juvenile and adult fishes, inadvertently 

herding them away from suitable habitat areas (e.g., nurseries, foraging, mating, spawning, migratory 

corridors) and concentrating many fishes in areas of unsuitable use. Neither of these scenarios is likely to 

occur in 2006. 

We are aware of no studies investigating the impacts of seismic disturbance on spawning behavior. We 

offer the following as possible scenarios. Migratory delays of fishes returning to spawn may translate into 

adverse impacts on spawning activity and/or the survival of offspring, because the timing of the spawning 

is evolutionarily conditioned to coincide with environmental conditions favorable to maximize the survival 

of offspring and later life-history stages. This is particularly so for Pacific herring, capelin, Pacific salmon 

(chiefly pinks and chums), arctic cisco, least cisco, broad whitefish, and Pacific sand lance. Of these 

species, Pacific herring and arctic cod are hearing specialists and may be the most acoustically sensitive 

species occurring in the planning areas. In addition, these coastwise migratory fishes (e.g., Pacific herring, 

capelin, Pacific salmon, whitefishes, and Pacific sand lance) are important prey to other marine fishes, 

seabirds, marine mammals, and subsistence fishers. 

The OBC surveys in shallow and very shallow waters may pose somewhat different potential barriers to 

coastwise migrating fishes than do marine streamer seimic surveys. An OBC seismic survey typically 

covers a smaller area (approximately 16 by 32 km [10 by 20 mi]) and may spend days in an area. While 

transmission loss is greater in waters that OBC surveys are conducted, survey activity persisting in a 

specific area for days likely poses longer temporal barrier to coastwise migrations. The 3D/2D streamer 

seismic surveys may cover a much larger area (thousands of square miles) and only stay in a particular area 

for hours, thereby posing somewhat transient disturbances, typically employing an offset racetrack pattern. 

Such operations have the potential to not permit migratory fishes to pass once the airgun arrays move 

seaward to the backside of an offset racetrack pattern, because the zone of influence still persists close to 

the coast. It is uncertain in what context or to what extent coastwise migrating fishes might deflect from a 

seismic survey operation. 

Migratory species more at risk of spawning delays include Pacific herring, capelin, Pacific salmon (chiefly 

pinks and chums), arctic cisco, least cisco, broad whitefish, and Pacific sand lance. Pacific herring and 

arctic cod are hearing specialists and are most likely the most acoustically sensitive species occurring in the 

planning areas. They are therefore the most likely to exhibit displacement and avoidance behaviors of the 

 PEA-58 
arctic fishes occurring in the planning areas. Pacific salmon and the whitefish are 

anadromous/amphidromous species that spawn in freshwater habitats of the Arctic coast. Pacific herring, 

capelin, and Pacific sand lance spawn on beaches or in nearshore waters. 

Arctic cisco are an important subsistence resource to the coastal villages along the northeastern 

Chukchi and Beaufort seas. Arctic cisco found in the Alaskan Beaufort Sea are believed to originate 

from spawning grounds in the Mackenzie River system of Canada (Gallaway and Fechhelm, 2000). In 

spring, newly hatched young-of-the-year (age 0) are flushed downriver into ice-free coastal waters 

adjacent to the Mackenzie Delta. Some young-of-the-year are transported westward to Alaska by 

wind-driven coastal currents. In summers with strong and persistent east winds, enhanced westward 

transport can carry fish to Alaska’s Colville River until the onset of sexual maturity beginning at about 

age 7, at which point they migrate back to the Mackenzie River to spawn. The Sagavanirktok River, 

100 km east of the Colville River, contains far less overwintering habitat than the Colville system, but 

appears capable of supporting newly recruited, young-of-the-year fish for several years. These 

juveniles eventually disappear from the Sagavanirktok system, typically by age 3. Although their fate 

is unknown, some fish probably survive by finding their way to the Colville River. Summers of 

strong, persistent east winds are associated with strong year-classes in the Colville/Sagavanirktok 

region. In contrast, few young-of-the-year fish arrive in central Alaska in years of weak east winds 

and correspondingly poor westward transport. The Alaskan arctic cisco population is, thus, 

characterized by strong and weak year-classes, the patterns of which are determined largely by summer 

wind patterns. More information concerning arctic cisco is described in Appendix B. 

As a general rule, if there is no recruitment of young-of-the-year to the Colville/Sagavanirktok region, 

there is no appreciable recruitment of that year class (i.e., age cohort) in following summers (Gallaway 

and Fechhelm, 2000). If young-of-the-year fish are not transported far enough west in their first 

summer to overwinter in the Colville or Sagavanirktok rivers, they are forced to overwinter in 

mountain streams (to the east), where relatively few may survive. Seismic surveys conducted in the 

migratory corridor of young-of-the-year Arctic cisco may adversely effect recruitment to the 

Colville/Sagavanirktok region as wind-advected young-of-the-year may experience direct effects (e.g., 

physical harm; behavioral responses such as displacement as possible) and indirect effects (e.g., 

increased predation, displacement from suitable habitat to less suitable habitat that include less suitable 

overwintering areas). 

Migratory delays of fishes returning to spawn may translate into adverse impacts on spawning activity. For 

example, capelin spawn on beaches or in deeper water and are highly specific with regard to spawning 

conditions. Capelins generally prefer smooth sand and gravel beaches for spawning. At spawning 

grounds, capelin are segregated into schools of different sexes. The general pattern seems to be that ripe 

males await opportunities to spawn near the beaches, while large schools, mainly composed of relatively 

inactive females, remain for several weeks off the beaches in slightly deeper water (i.e., staging area). As 

these females ripen, individuals proceed to the beaches to spawn. Thus, most males remain in attendance 

near the beaches and join successive small groups of females that spawn and depart from the area. Airgun 

emissions from surveys conducted in Federal waters adjacent to capelin spawning grounds may ensonify 

capelin staging and spawning areas. Aggregations of ripe males, ripe females, or both, may be sufficiently 

disturbed so as to depart staging areas or spawning areas for the duration of the survey, thereby potentially 

delaying spawning activity. 

Migratory delays of fishes returning to spawn may translate into adverse impacts on the survival of new 

offspring. Migration and spawning among many fishes is evolutionarily tuned to coincide with 

environmental conditions favorable to maximize the survival of offspring. While many populations exhibit 

some ecological plasticity to accommodate environmental variability, arctic fish populations may not be so 

plastic. Arctic fish are subjected to abbreviated summers and long winters that greatly may limit their 

ability to ecologically respond to spawning delays. Such constraints may be most evident in and important 

to coastwise migratory fishes returning to spawn in the Mackenzie River or in other Canadian waters, as 

these fishes must travel farther to spawn than those fishes spawning in Alaskan waters. Spawning delays 

for Alaskan or Canadian parent stocks may translate into delayed hatching of eggs that subsequently 

 PEA-59 
translate to premature exposure of eggs to winter conditions, which may increases the mortality of all or 

some of the new cohort due to freezing. 

Spawning delays may translate into multiple cascading adverse impacts to new cohorts. Behavioral 

strategies of each lifestage are evolutionarily timed to coincide with environmental conditions favoring 

survival to the next lifestage. Late spawning leading to late egg hatching leading to late larval development 

introduces temporal fractures in evolutionarily tested behavioral strategies that may adversely influence 

ecological food webs. Such temporal fractures may disrupt favorable environmental conditions for larval 

fish survival and recruitment to the greater population. For example, the timing of juvenile development 

typically coincides with the availability of suitable prey both spatially and temporally. Larvae or fry whose 

development is delayed may no longer have access to suitable prey, because their suitable prey may have 

moved to different areas as part of their life cycle or are no longer of suitable size for consumption by the 

young fish. 

As one example, near Point Barrow, Bendock (1977) only captured capelin during a 2-week period in midAugust when spawning took place within the surf along exposed gravel beaches. Capelin eggs are 

demersal and attach to gravel on the beach or on the sea bottom. The incubation period varies with 

temperature, and hatching has been demonstrated to occur in about 55 days at 0  ̊C, 30 days at 5  ̊C, and 15 

days at 10  ̊C. Newly hatched larvae soon assume a pelagic existence near the surface, where they remain 

until winter cooling sets in, when they move closer to the sea bottom until waters warm again in spring. 

Delays to capelin spawning in mid-August by a week or more may result in the delayed hatching of eggs as 

environmental conditions begin cooling in early September. Assuming that capelin eggs hatch before 

landfast ice begins to form on beaches (they may not, depending on migratory delay length and 

temperatures during the incubation period), young capelin assume a pelagic existence near the surface, 

presumably feeding on zooplankton, until winter cooling set in. In the Beaufort Sea, the growth rates of 

planktonic and epontic organisms are relatively rapid, and the generation lengths are relatively short. For 

example, the body weight doubled every 2 weeks among immature stages of the common mysid, Mysis 

litoralis, during summer 1977-1978 field studies in Simpson Lagoon, and the generation length was 1-2 

years (USDOI, MMS, 2003a, citing Griffiths and Dillinger, 1980). The rapid growth rates also were 

evident during formation of typical summer “blooms” during 1977 and 1978. Capelin caught in nearshore 

waters of the northeastern Chukchi Sea consumed mysids, and presumably also do so in the Beaufort Sea. 

Prey of suitable size (e.g., mysids) may no longer be available to young pelagic capelin to forage on. 

Moreover, young fish may face predators otherwise not typically encountered. Picivorous fishes typically 

are limited to consuming fishes smaller than their mouth gap. Therefore, younger fishes (i.e., smaller 

fishes) may be preyed on more readily by larger fishes. For example, Beaufort Sea coastal waters appear to 

be an important nursery area for age-0 capelin and other fishes throughout the summer. Late developing 

capelin emigrating to coastal waters from beaches where they underwent delayed hatching may be more 

suitable prey for older and larger piscivorous species, such as cod, haddock, salmon, and herring. 

III.F.1.i(2(d) Impacts from Vessel Noise. Engine-powered vessels may radiate considerable levels of noise 

underwater. Diesel engines, generators, and propulsion motors contribute significantly to the lowfrequency spectrum. Much of the necessary machinery to drive and operate a ship produces vibration, 

within the frequency range of 10 Hz to 1.5 kHz, with the consequence of radiation in the form of pressure 

waves from the hull (Mitson and Knudsen, 2003). In addition to broadband propeller noise, there is a 

phenomenon known as “singing,” where a discrete tone is produced by the propeller, usually due to 

physical excitation of the trailing edges of the blades. This can result in very high tone levels within the 

frequency range of fish hearing. The overall noise of a vessel may emanate from many machinery sources. 

Pumps in particular often are significant producers of noise from vibration and, at higher frequencies, from 

turbulent flow. Sharp angles and high flow rates in pipework also can cause cavitation, and even small 

items of machinery might produce quite high levels of noise. 

Mitson and Knudsen (2003) examined the causes and effects of fisheries research-vessel noise on fish 

abundance estimation, and noted that avoidance behavior by a herring school was shown due to a noisy 

vessel; by contrast, there is an example of no reaction of herring to a noise-reduced vessel. They note a 

study wherein the FRV Johan Hjort was using a propeller shaft speed of 125 revolutions per minute, giving 

 PEA-60 
a radiated noise level sufficient to cause fish avoidance behavior at 560 m distance when traveling at 9 

knots (kn), but it reduced to 355 m at 10 kn. Their Figure 5 shows that large changes in noise level occur 

for a small change in speed. Their data also suggest abnormal fish activity continues for some time as the 

vessel travels away from the recording buoy used in the study. 

Vessel traffic associated with the seismic surveys, including the seismic survey vessels and accompanying 

guard/chase boat or utility boat, are used chiefly during ice-free conditions (summer months). Vessel 

traffic may disturb some fish resources and their habitat during operations. Pacific salmon and EFH in the 

coastal and marine environment may be disturbed by vessel-traffic noise. However, vessel noise is 

expected to be chiefly transient; fishes in the immediate vicinity of such vessels are believed likely to avoid 

such noise perhaps by as much as several hundred meters. Vessel noise is likely to be of negligible impact 

to fish/fishery resources and EFH. 

III.F.1.i(2)(e) Impacts from Anchor or Cable Deployment and Recovery. Anchoring by vessels is 

sometimes a necessary practice that locally may disturb the seafloor. In anchoring a vessel or in weighing 

anchor, fish resources may be crushed or injured during the practice. Anchors may not hold fast under 

some conditions and drag across the seafloor, tearing up sessile organisms (e.g., sponges, corals, kelp) or 

their habitats (e.g., boulders). Anchoring in fragile biocenoses, such as the Boulder Patch, any coral/sponge 

gardens, or macroalgae gardens (e.g. kelp beds) likely would yield more damage to fish resources and 

habitat than anchoring offshore in sand or mud biocenoses. The magnitude of damage would depend 

chiefly on exactly where anchors were placed, whether an anchor drags, and what an anchor might drag 

across. 

Section II.A.4 describes the physical layout and general operations of 3D/2D seismic surveys. Cables 

deployed from seismic-survey vessels typically extend well beyond the vessel. These are towed several 

meters below the sea surface and, if passed across fragile biocenoses (e.g., kelp beds or boulder patches), 

may foul, hang up, and/or damage fragile biocenoses and the towed equipment. Vessels towing cable 

streamers are restricted in their maneuverability, compounding their ability to avoid dragging cables across 

fragile biocenoses in the survey area. Additionally, currents may influence the actual position of deployed 

cables. Fouling, hangups, and/or damage is avoidable in most cases, given that any known fragile 

biocenoses in shallow water are given a wide berth by vessel operators and any cables they deploy. 

III.F.1.i(2)(f) Impacts from Fuel Spills. The MMS assumes that marine resources could be exposed to 

accidentally spilled lubricating oil or diesel fuel from a vessel associated with seismic-survey operations or 

by a leaking or torn streamer array under tow by a vessel. The liquid used to fill and provide streamer 

buoyancy is usually liquid paraffin that is biodegradable and evaporates very quickly. The impacts on 

fish/fishery resources and EFH from streamer array spills are regarded as negligible. 

Eight refueling operations (one per marine seismic survey operation) are expected to occur during the 2006 

seismic survey season. The MMS believes that the incidents involving the release of oil and fuel from 

vessels during refueling would likely be small, on the order of <5 gallons (gal) per refueling event; in total, 

approximately 40 gal (20 gal in the Chukchi Sea and 20 gal in the Beaufort Sea) of fuel might be spilled 

during the 2006 seismic-survey season. Refueling operations in the Beaufort Sea likely would occur at 

Prudhoe Bay’s West Dock facility, and refueling operations in the Chukchi Sea likely would occur at sea 

with the use of fuel-supply vessels. Accidental spills associated with refueling operations are not likely to 

occur in the same location at the same time. Each accidental spill of 5 gal or less likely would impact local 

areas and adversely effect EFH and relatively few fish. Such small spills are ephemeral events and would 

not likely result in chronic impacts to fish/fishery resources or EFH. Refueling operations at West Dock in 

the Beaufort Sea are likely routine and the facility is assumed to be highly responsive to any fuel spills. 

Refueling operations at sea in the Chukchi Sea are likely more tenuous than at West Dock in the Beaufort 

Sea. An accidental spill offshore would likely be of low impact relative to a spill in coastal waters that 

serve as important spawning, nursery, and feeding areas. The periodic accidental spills of approximately 5 

gal during the eight refueling operations is not believed likely to result in a significant impact to fish/fishery 

resources or EFH in either the Chukchi or Beaufort seas. 

 PEA-61 
III.F.1.i(2)(g) Impacts to Commercial Fisheries. The majority of fisheries conducted in the Alaskan 

portions of the Chukchi and Beaufort seas are of a subsistence nature and are conducted close to shore. A 

State-managed commercial fishery for salmon operates in Kotzebue Sound well to the south of the Chukchi 

Sea Planning Area. The salmon fishery is relative small (40-43 permits of an allowance of 180 possible 

permits) and occurs in coastal waters. Also, a very small (3-4 vessel) commercial snow crab fishery 

operates in Federal waters; however, it is believed that the fishery for snow crab takes place well south of 

Point Hope and outside of the Chukchi Sea Planning Area. Because these fisheries operate well to the 

south of the Chukchi Sea Planning Area, we do not anticipate adverse impacts from seismic surveys on 

these commercial fisheries. 

In the Alaskan Beaufort Sea, a small, under-ice commercial fishery is operated by the Helmericks family in 

the Colville River Delta from early October through late November. Seismic surveys are not anticipated to 

occur in the Beaufort Sea Planning Area when ice is forming in coastal waters and, therefore, are not 

expected to adversely impact the Colville River under-ice commercial fishery. 

The differences between Alternatives 3-6 are inconsequential to this assessment of commercial fisheries. 

Adverse impacts to the noted commercial fisheries in the region are not expected, provided that seismic 

vessels brought into the Chukchi and Beaufort seas planning areas do not introduce aquatic invasive 

species, which would have the potential to significantly impact fishery resources and commercial fisheries. 

The seismic vessels are subject to U.S. Coast Guard regulations to prevent the introduction of aquatic 

invasive species. 

III.F.1.i(2)(h) Impacts from Coincidental Multiple Seismic Surveys. Given the limited evidence of 

avoidance and displacement from survey areas, the interaction of coincident multiple surveys may 

influence the distribution of some juvenile and adult fishes, inadvertently herding them away from suitable 

habitat areas (e.g., nurseries, foraging, mating, spawning, migratory corridors, access to overwintering 

sites) and concentrating many fishes in areas of unsuitable use. Such areas may not include suitable prey 

species or in densities to support the concentrated fishes. Displacement may also expose them to more 

predation than naturally experienced. 

For example, seasonal abundance of Arctic cisco in Beaufort Sea coastal waters is a function of the 

fishes’ foraging range during the open-water season (Gallaway and Fechhelm, 2000). Summer studies 

conducted along the coast (between the Mackenzie and Colville rivers) report collecting substantial 

numbers of large cisco. This coastwide distribution implies extensive dispersal from overwintering 

grounds. The ability to traverse large distances along the coast also is consistent with the premise that 

adults from the Colville River eventually migrate more than 600 km back to the Mackenzie River to 

spawn. The summer coastal dispersal of juvenile Arctic cisco is more localized around their 

overwintering drainages, perhaps because juveniles are too small to range as far as adults. Multiple 

seismic surveys that adversely influence the summer feeding habitat and migratory corridors used by 

Arctic cisco may displace fish to unsuitable habitat that leads to increased competition for prey as 

available, herd juvenile Arctic cisco afar from localized and preferred habitat; impede access to 

suitable overwintering sites, each thereby decreasing winter survival. One or more seismic surveys in 

the migratory corridor between the Colville and the Mackenzie rivers may delay the spawning 

migration of adult Arctic cisco to spawning grounds in the Mackenzie River. All serve to adversely 

affect recruitment within the population. However, multiple surveys in the migratory corridor are not 

expected to occur in 2006. 

Surveys may facilitate the stranding of some schooling or aggregated arctic fishes onto coastal or insular 

beaches in the planning areas. Such strandings may be more likely if multiple surveys were to spatially 

“box in” fishes along the shoreline and, thus, limit their avenues of retreat to less ensonified waters. As an 

example, let’s consider arctic cod. 

(1) Schools of arctic cod occurring in the western Arctic generally tend to be found in bays 

and inlets, where they pool in deep basins (e.g., Craig et al., 1982; Welch, Crawford, and 

Hop, 1993). When occurring on open coastlines or off points, they move along the shore 

in shallow water and end up in bays (e.g., Craig et al., 1982; Welch, Crawford, and Hop, 

 PEA-62 
1993). Arctic cod appear to behave similarly in other areas (Welch, Crawford, and Hop, 

1993). 

(2) Under certain circumstances, it appears that arctic cod are susceptible to massive 

mortalities that have been observed at widespread locations in the Arctic (Craig et al., 

1982). Mass strandings also have been observed after severe storms in Alaskan waters 

(Craig et al., 1982) and Russian waters (Hop, Welch, and Crawford, 1997, citing 

Shibanoff, 1958; Moskalenko, 1964). Typically in autumn or winter when the fish have 

moved close to shore, large numbers of dead arctic cod have been found stranded on 

beaches (Craig et al., 1982). At Cape Lisburne, an estimated 19, 000 arctic cod were 

observed along a 3.2-km length of the beach after a large August storm in 1978 (Craig et 

al., 1982). MacGinite (1955, as cited by Craig et al., 1982) noted large numbers of cod 

washing ashore during storms at Point Barrow. Schools of arctic cod also probably often 

are induced by predators (e.g., beluga whale and narwhal to mass strand on arctic beaches 

as predators forced fish into shallow water (Welch, Crawford, and Hop, 1993). It is 

unknown whether the physical chase by marine mammals causes the fish to strand in 

mass or whether fish strand because they detected and are herded by the acoustic signals 

given off by the marine mammals. The latter hypothesis appears more plausible, given 

that mass strandings associated with a physical chase likely would be very concentrated 

at the shoreline. The use of sound by marine mammals to herd cod conceivably would 

influence a larger area and more fish without expending the energetics necessary to 

physically herd and chase fish to strand ashore. Once cod schools are stranded, they may 

be preyed on by seabirds. 

(3) Researchers have suggested that sound is an important orientation or communication 

stimulus to arctic cod. Atlantic cod (Gadus morhua; of the same genus as arctic cod) is a 

known hearing specialist and sensitive to frequencies ranging from approximately 20-140 

Hz (Popper et al., 2003:Figure 1.4)—all well within the range of airgun emissions. 

Recall that hearing specialists hear with greater sensitivity and over a wider frequency 

range than hearing nonspecialists. For most sound sources (vibrating bodies) and under 

many environmental conditions, specialists will be able to detect the sound at lower 

source levels of motion or energy, at greater distances, and at higher frequencies than 

nonspecialists. 

(4) Seismic surveys using airguns have been shown to disturb and displace Atlantic cod, 

causing them to leave the survey area during seismic surveys (Table III.F.3). Areas 

apparently affected extended up to 33 km from the survey. 

(5) As multiple seismic surveys work the Chukchi Sea and Beaufort Sea Planning Areas, 

they individually and synergistically may herd arctic cod around the planning areas. 

Noise from natural acoustic sources (e.g., ice, cetaceans) also may interact with airgun 

emissions to influence deflection and displacement of cod. Theoretically, seismic 

surveys operating near the coast may cause arctic cod to concentrate in small, coastal 

areas (e.g., bays) and may directly or indirectly cause schools of arctic cod to strand on 

coastal or insular beaches. While this stranding effect has not been observed in the past, 

during which hundreds of thousands of miles of seismic data have been collected, it has 

not been specifically monitored either. To address the possibility of this behavioral 

response, we have a mitigation that require separation of seismic operations. 

III.F.1.i(3) Potential Impacts to Essential Fish Habitat. Airgun emissions from seismic surveys 

conducted in the Chukchi/Beaufort seas planning areas may ensonify and adversely affect Pacific salmon 

essential fish habitat (EFH). Seismic airgun emissions also extend into infrasound (sound below 20 Hz) 

levels (as low as 10 Hz; see Sections II.A.4 and III.C). Juvenile salmonids display strong avoidance 

reactions to infrasound, and infrasound has been used as an effective acoustic barrier for downstream 

migrating Atlantic salmon (Salmo salar) smolts. Therefore, airgun emissions may act to deflect and 

displace Pacific salmon fry from nursery habitat in coastal waters of the planning areas, or to herd salmon 

around in offshore waters. As in the capelin and arctic cisco examples, deflection and displacement from 

suitable nursery and foraging habitat may adversely affect the survival of juvenile Pacific salmon and their 

recruitment to a breeding cohort. 

 PEA-63 
Other direct and indirect impacts that may occur to Pacific salmon or their EFH include acoustic and/or 

vestibular harm, herding, migratory delays and cascading impacts, disruption and displacement from 

feeding areas, and strandings. Impacts are variable and context specific; therefore, the exact magnitude of 

impacts is undeterminable because of the large uncertainties as to the distribution, abundance, densities, 

habitat areas and uses, migratory patterns, and population trends of Pacific salmon in these areas. Pacific 

salmon are relatively rare because of very low population numbers evidently in the region. Adverse 

impacts such as displacement of Pacific salmon fry from nursery habitat areas in coastal waters of the 

planning areas may make them more vulnerable to predation by other fishes occurring in higher 

concentrations as a result of displacement from their preferred habitat. As Pacific salmon have very low 

population numbers in the Chukchi and Beaufort seas, effects other than those that are very local or 

temporary may have local population-level implications. 

Squid exposed to airgun emissions may exhibit strong startle responses to a nearby airgun starting up by 

firing their ink sacs and/or jetting directly away from the airgun source. Avoidance may persist for an 

undetermined time or, as demonstrated by experimental trials, squid may instead increase their swimming 

speed on approach of the airgun but then slow at the closest approach and remain close to the water surface 

during the airgun operations. The MMS lacks information on the species of squid inhabiting the Chukchi 

Sea and Beaufort Sea Planning Areas. However, squid do occur in the planning areas as, on occasion (e.g., 

in 1998 and 2005, they washed up along the beach near Barrow [George, 2005, pers. commun.]). It is 

generally thought that the number of squid species in the Arctic Region is relatively low compared to more 

temperate waters of the world. The distribution and abundance of various squid in the planning areas also 

are unknown. Anticipated effects are limited to behavioral responses such as those noted and are regarded 

as negligible to squid populations. 

Snow crab is a commercially fished and managed species in the Bering Sea. It is commercially harvested 

in the southeastern Chukchi Sea. Snow crabs exposed to airgun emissions are not expected to suffer any 

acute or midterm mortality. Mature, postmolted females carrying second-year eggs may be adversely 

impacted, experiencing abnormalities and some hemorrhaging in the ovaries or hepatopancreas (similar 

function to a liver). The survival of embryos carried by female crabs, and locomotion of the resulting 

larvae after hatch, are not expected to be affected by a seismic survey. Other physical impacts appear 

possible but are debatable, given the limitations of the study reported by the CDFO (2004a,b). Studies 

designed to clarify the important data deficiencies identified in the CDFO study regarding the effects of 

airgun emissions on snow crabs could be conducted in the Chukchi Sea to resolve the uncertainties 

stemming from the CDFO study. 

III.F.1.j. Assessment of Alternatives. The following provides a comparison across the various 

alternatives of potential impacts to fish resources, EFH, and commercial fisheries in the Chukchi Sea and 

Beaufort Sea Planning Areas. This assessment is based on the available scientific and management 

information reviewed above. Sections I and III.C describe seismic-survey operations, the Proposed Action, 

airguns and their emissions (i.e., frequency range and sound-pressure levels), and the acoustic environment. 

Section III.F.1.i(2) above provides a summary of the current state of scientific knowledge on the range of 

potential impacts to marine fish and invertebrates from seismic activity similar to that described under the 

Proposed Action and various alternatives. 

Alternative 1, the no-action alternative, poses no adverse impacts to fish/fishery resources or EFH. 

Alternatives 3 through 6 all equally employ mitigation measures beyond those in the Proposed Action to 

avoid or limit the potential for impacts to fish resources and EFH. As these measures apply across 

Alternatives 3 through 6, there remains little difference across the various alternatives as to the degree of 

impacts for this species group and related issues. In theory, the alternatives with the more restrictive 

exclusion zones for marine mammals (Alternatives 3 and 5) would provide more protection for marine fish 

and invertebrate species if shutdown were to occur, but again this would be considered only incrementally 

more protective for fish, invertebrates and related issues. 

III.F.1.k. Mitigation Measures. Alternatives 3 through 6 all equally employ mitigation measures beyond 

those in the Proposed Action to avoid or limit the potential for mortality and behavioral impacts to fish 

 PEA-64 
resources and EFH. These mitigation measures also are specifically designed to limit potential impacts to 

migration, spawning, rare species, subsistence fishing, and operation of multiple seismic surveys. These 

measures are outlined in Section IV. 

Seismic cables and airgun arrays shall not be towed in the vicinity of fragile biocenoses, unless MMS 

determines the proposed operations can be conducted without damage to the fragile biocenoses. 

• Based on the information provided by MMS on the known locations of fragile biocenoses in 

the Chukchi and Beaufort seas, the applicant shall clearly explain to what distance their 

operations will avoid fragile biocenoses and how they will avoid damaging fragile biocenoses. 

• Permittees shall report to MMS if damage to fragile biocenoses occurs as a result of their 

operations. Additionally, Permittees shall notify MMS if they detect any fragile biocenoses 

otherwise not documented in their permit application. 

Vessels shall not anchor in the vicinity of any documented fragile biocenoses (e.g., the Boulder Patch, 

natural gardens of coral/sponge or macroalgae [e.g., kelp beds]), unless an emergency situation involving 

human safety specifically exists and there are no other feasible sites to anchor at the time. 

III.F.1.l. Conclusions. Overall, the Proposed Action and Alternatives 3 through 6 potentially could 

adversely impact EFH and fish/fishery resources. Many fish species are likely to hear airgun sounds as far 

as 2.7-63 km (1.6-39 mi) from their source, depending on water depth. Fish responses to seismic sources 

are species specific and may differ according to the species’ lifestage. Immediate mortality and 

physiological damage to eggs, larvae, and fry, adult and juvenile marine fishes is unlikely to occur, unless 

the fish are present within 5 m of the sound source (although more likely 1 m). The potential for physical 

damage is related to the characteristics of the sound wave, the species involved, lifestage, distance from the 

airgun array, configuration of array, and the environmental conditions. Damage to tissue may not be 

immediately apparent. 

Behavioral changes to marine fish and invertebrates may include balance problems (but recovery within 

minutes); disoriented swimming behavior; increased swimming speed; tightening schools; displacement; 

interruption of important biological behaviors (e.g., feeding, mating); shifts in the vertical distribution 

(either up or down); and occurrence of alarm and startle responses. Some fishes may be displaced from 

suitable habitat for hours to weeks. Thresholds for typical behavioral effects to fish from airgun sources 

occur within the 160-dB to 200-dB range. 

Potential impacts from vessel noise, anchor or cable deployment, and recovery of fuel spills is regarded as a 

negligible adverse but not significant impact to fish/fishery resources and EFH. Commercial fisheries in 

the region are not expected to be impacted. There is a potential for impacts to migration, spawning or 

subsistence fishing. 

There is relatively little information concerning the distribution and abundance of populations of rare fish 

resources from which to determine whether exposure to seismic airgun emissions would result and 

subsequently lead to a decline in abundance and/or change in distribution requiring one or more generation 

for the indicated population to recover to its former status. It is logical to assume that these species would 

experience the same types of behavioral impacts and potential for immediate mortality as other fish species 

in the Proposed Action area. Therefore, despite the relatively limited information on these resources, the 

Proposed Action and various alternatives with the mitigation implemented could result in adverse but not 

significant impacts to rare fish resources in the Proposed Action area. 

The MMS concludes, based on the above assessment, that the Proposed Action and Alternatives 3 through 

6 would have adverse but not significant impacts on fish/fishery resources and EFH. The analysis notes 

specific issues that were afforded additional assessment given their importance to fish survival and 

reproduction and human uses, including impacts to migration and spawning, rare species, subsistence 

fishing, and operation of coincidental multiple seismic surveys. However, based on the above assessment, 

MMS concludes that the potential for impacts to these issues (e.g., migration, spawning, rare species, and 

subsistence fishing) also is adverse but not significant. In addition, vessels may not anchor and seismic 

 PEA-65 
cables and arrays would not be towed within the vicinity of known fragile biocenoses, unless MMS 

determines the proposed operation can be conducted without damage to the fragile biocenoses. Again, 

these measures would be consistent across Alternatives 3 through 6. 

The MMS also considered the issue of basing its assessment on limited or lacking information on specific 

fish resources in the Alaskan Arctic. A review of the available science and management literature shows 

that at present, there are no empirical data to document potential impacts reaching a population-level effect 

nor have the experiments conducted to date contained adequate controls in place to allow us to predict the 

nature of a change or that any change would occur. The information that does exist has not demonstrated 

that seismic surveys would result in significant impacts to marine fish or related issues (e.g., impacts to 

migration/spawning, rare species, subsistence fishing). Therefore, based on the above review of available 

scientific and fishery management literature, MMS believes that seismic surveys as defined under the 

Proposed Action could result in adverse but not significant impacts to fish resources, EFH, and 

commercial/recreational fisheries. 

III.F.2. Marine Birds.

III.F.2.a. Threatened and Endangered Marine Birds. 

III.F.2.a (1) Spectacled Eider (Somateria fischeri). All spectacled eider populations were listed as a 

threatened species under the Endangered Species Act in May 1993. Listing was due to an estimated 96% 

decrease in nesting abundance in the Yukon-Kuskokwim Delta (Y-K Delta) from the 1970’s to the early 

1990’s and uncertainty about the trends in nesting abundance on the arctic coastal plains in Alaska and 

Russia. The breeding population on the North Slope currently is the largest breeding population of 

spectacled eiders in North America. An estimated 4,744 pairs (± 907 pairs, average ± 2 standard errors of 

the sample) of spectacled eiders breed on the Arctic Coastal Plain of Alaska (66 FR 9146-9185). This 

breeding population represents about 2-3% of the estimated world population of 363,000 spectacled eiders 

(USDOI, FWS, 1999). Other major breeding populations are in the Y-K Delta and the Arctic Coastal Plain 

of Russia. The nonbreeding segment of any of the populations is unknown. Based on survey data, the 

spectacled eider breeding population on the North Slope has not shown a significant decline throughout 

most of the 1990’s. The downward trend of 2.6% per year is bounded by a 90% confidence interval 

ranging from a 7.7% decline per year to a 2.7% increase per year (66 FR 9146-9185). 

During the open-water period when seismic-survey activities are possible, spectacled eiders often are 

encountered moving between tundra breeding areas on the North Slope and the primary molting area at 

Ledyard Bay in the Chukchi Sea. The most accurate data on spectacled eider movements between 

breeding, molting, and wintering habitats is described in Petersen, Larned, and Douglas (1999) and forms 

the basis for the following discussion. 

Spectacled eiders do not breed until age 2-3 years. The abundance and distribution of non-breeding eiders 

is unknown, but they presumably remain at sea. Paired male spectacled eiders begin their movement from 

nesting areas on the North Slope from late June to early July after the nest is initiated; unsuccessful females 

follow in late summer and successful females leave the nesting grounds in late August to September. 

Movement between North Slope breeding areas and the primary molting area in Ledyard Bay typically 

takes several weeks, indicating that several stops are made along the way in the Beaufort and Chukchi seas. 

The physiological importance of the stops during this extended migration is undetermined, but these stops 

could be very important to molt timing and survival during and after the molt. During this period of 

migration, most spectacled eiders travel offshore. Based on telemetry data for molt migration, male 

spectacled eiders migrate an average of 7 km offshore of the Beaufort Sea coast, and females fly an average 

of 17 km offshore (Figure III.F-1). This 10-km difference may be attributed to variation in the distance of 

ice from shore, and distance might change between years based on the extent of ice retreat. Based on 

telemetry data for molt migration in the Chukchi Sea, male spectacled eiders migrate an average of 35 m 

offshore of the Chukchi Sea coast, and females fly an average of 60 km offshore. 

Ledyard Bay is an important molting area for North Slope-breeding spectacled eiders in the summer 

(males) and fall (breeding females). Using satellite telemetry, Petersen, Larned, and Douglas (1999) 

 PEA-66 
determined that most spectacled eiders molting at Ledyard Bay were between 30 and 40 km offshore. 

About 33,200 spectacled eiders were observed using Ledyard Bay during an aerial survey in September 

1995. Most were concentrated in a 37-km-diameter circle, with their distribution centered about 67 km 

southwest of Point Lay and 41 km offshore. During the molt, eiders are flightless for a period of a few 

weeks. On average, male spectacled eiders arrive at molt locations in Ledyard Bay around the end of the 

first week of July and depart for wintering areas by the middle of September. Females with broods arrive 

around the end of the first week of September and depart around the middle of October (Petersen, Larned, 

and Douglas, 1999). Molting spectacled eiders may be encountered in this area during most of the openwater period. The Ledyard Bay area was designated critical habitat for the spectacled eider in 2001 

(USDOI, FWS, 2001) (Figure III.F-2). The critical habitat includes the waters of Ledyard Bay within 

about 74 km (40 nmi) from shore, excluding waters less than 1.85 km from shore. 

Although this relatively discrete molting area is routinely used by spectacled eiders, it does not correlate 

with known areas of high benthic biomass identified by Grebmeier and Dunton (2000). It may be that 

eiders are foraging on invertebrates in the water column or in epibenthic habitat. Although benthic biomass 

also is considered low in the Norton Sound molting area, spectacled eiders are thought to feed on locally 

abundant large snails (66 FR 9146-9185). It is unknown if large snails are abundant in the Ledyard Bay 

molting area. 

III.F.2.a(2) Steller’s Eider (Polysticta stelleri). The Alaska-breeding population of Steller’s eiders was 

listed as a threatened species under the Endangered Species Act in June 1997. Three nesting populations of 

Steller’s eiders are identified: (1) western arctic Russia, (2) eastern arctic Russia, and (3) arctic Alaska 

(Nygard, Frantzen, and Svazas, 1995). In Alaska, Steller’s eiders primarily nest in two geographic areas: 

on the Y-K Delta and on the North Slope near Barrow. Most of the world population of Steller’s eiders 

nests in arctic Russia from the Yamal Peninsula to the Kolyma Delta (Nygard, Frantzen, and Svazas, 1995). 

Less than 5% of the breeding population nests in arctic Alaska (Rothe and Arthur, 1994). It is the leastabundant eider in Alaska, with a discontinuous historic breeding range along the coast from the Alaska 

Peninsula northward to the Beaufort Sea (Cooke, 1906; Rothe and Arthur, 1994; USDOI, FWS, 1996). On 

the North Slope, the greatest breeding densities are found near Barrow (Quakenbush et al., 2002), although 

they do not breed every year when present (Suydam, 1997). 

During the open-water period when seismic survey activities are possible, Steller’s eiders could be 

encountered in the Beaufort and Chukchi seas. Although a few Steller’s eiders might be encountered 

migrating along the Beaufort Sea coast during the period when seismic survey activities are possible, most 

use the Chukchi Sea as a migration corridor for fall migration. Paired male Steller’s eiders depart the North 

Slope after the nest is initiated in mid- to late June. In some years, for unknown reasons, paired eiders 

leave the North Slope without initiating a nest. In breeding years, female eiders and young-of-the-year 

typically depart the North Slope from late September to early October (Johnson and Herter, 1989). 

Because Steller’s eiders occur in such low numbers on the North Slope, it is difficult to observe large 

migrations by males after nest initiation or post-nesting females and young-of-the-year, as is the case with 

king and common eiders. It might be reasonable to expect that their movements would be loosely bounded 

by the distance of ice from shore and the water depth. It is unlikely that Steller’s eiders would be farther 

than 24 km offshore, because the water depth would be beyond their diving capability and the males would 

likely be traveling over sea ice. 

Martin (2006) used satellite telemetry to study the seasonal movements of Steller’s eiders. During fall 

migration, Alaskan breeding Steller’s eiders stop and rest in areas of the Alaska Chukchi Sea, often in 

nearshore waters (within 2 km of shore) near Ledyard Bay and Icy Cape. There was less use at more 

northerly locations near Wainwright and Peard Bay. More males than females migrated from Alaska to 

areas along the coast of Chukotka. Males that did not go to Chukotka spent more time on the Alaska 

Chukchi Sea coast. 

During extensive aerial surveys of Kasegaluk Lagoon in 1991, Johnson, Wiggins, and Wainwright. (1992) 

and Johnson, Frost, and Lowry (1992) found Steller’s eiders in one of three survey years. During 1991, 

there were 0.04 Steller’s eiders/km2

 compared with 21.59 long-tailed ducks/km2. Although Steller’s eiders 

 PEA-67 
may occur at greater densities outside Kasegaluk Lagoon, the total numbers probably are low given the low 

numbers that breed on the North Slope. 

Unlike spectacled eiders, Steller’s eiders do not molt in the Chukchi Sea. The primary molting areas are 

near Kuskokwim Shoals or in lagoons on the north side of the Alaska Peninsula. 

III.F.2.a(3) Kittlitz’s Murrelet (Brachyramphus brevirostris). This bird is listed as a candidate species 

throughout Alaska under the Endangered Species Act. This species may nest as far north as Cape Beaufort 

(100 km northeast of Cape Lisburne) in the Amatusuk Hills. Observations of breeding Kittlitz’s murrelets 

are sparse within the action area. Thompson, Hines, and Williamson (1966) observed a nest several miles 

inland on the Lisburne Peninsula northeast of Cape Thompson near Angmakrok Mountain. Breeding 

farther north is unlikely due to lack of suitable habitat (Day, Kuletz, and Nigro, 1999). The Lisburne 

Peninsula has not been searched for Kittlitz’s murrelets since 1983 (USDOI, FWS, 2004). These birds are 

solitary nesters and extensive survey effort is required to determine local abundance. Due to limited survey 

efforts, the size of the Kittlitz’s murrelet breeding population in the Lisburne Peninsula area remains 

uncertain. 

Foraging areas may occur in the action area. Kittlitz’s murrelets have been observed on a regular basis as 

far north as Point Barrow (Bailey, 1948). Regular observations of Kittlitz’s murrelets at sea were noted in 

late summer and early fall by Divoky (1987), but they have not been subsequently observed by others on 

similar cruises in the Chukchi Sea, suggesting that there is a great deal of annual variation in their 

occurrence in the Chukchi Sea. 

III.F.2.b. Other Marine Birds. Most marine birds are present in the Beaufort and Chukchi seas on a 

seasonal basis. Arrival times usually coincide with the formation of leads during spring migration to 

coastal breeding areas. Many seabirds (e.g., murres) and sea ducks (e.g., common eiders and long-tailed 

ducks) will closely follow leads during spring migration. Although ice-associated migration is a critical 

aspect of life for these birds, it will not be discussed further because marine seismic work considered in this 

document involves ship-based surveys. These ships must operate during relatively ice-free periods, so 

seismic surveys will not be conducted and seismic survey vessels will not be present in the area during 

spring migration. Departure times from the Beaufort and Chukchi seas for the fall and winter vary between 

species and often by sex within the same species, but most marine birds will have moved out of the 

Beaufort and Chukchi seas by late fall before the formation of sea ice. 

III.F.2.b(1) Cliff-nesting Seabirds.

III.F.2.b(1)(a) Murres. Common murres (Uria aalge) and thick-billed murres (U. lomvia) breed as far 

north as Cape Lisburne. Murres breed on cliffs and colonies and often are intermingled. Approximately 

100,000 murres nest at Cape Lisburne, of which about 70,000 were common murres (USDOI, FWS, 2005). 

Farther south at Cape Thompson, there are about 390,000 nesting murres, of which 75% are thick-billed 

murres (Fadely et al., 1989). Long-term monitoring at Cape Thompson indicates a ~50% decline in murre 

numbers (species combined) since 1960, whereas the colony at Cape Lisburne has more than doubled 

between 1976 and 1995 (Fadely et al., 1989; Roseneau, 1996). 

There are a few important aspects of murre breeding biology that are relevant to seismic surveys. Hatch et 

al. (2000), used satellite telemetry in the mid-1990’s to document that the foraging ranges of the Cape 

Thompson and Cape Lisburne colonies were almost completely separate. The Cape Thompson colony 

foraged primarily southwest to southeast and north to Point Hope, whereas the Cape Lisburne colony 

foraged primarily northwest to northeast. These distributions were similar during the two summers of the 

study. Distances to foraging areas at Cape Lisburne for a thick-billed murre averaged 66 ± 26 km (range 

47-84 km, n = 2 foraging bouts) and 79 ± 26 km (range 44-114, n = 8 foraging bouts) in a single common 

murre. These ranges are for likely breeders; failed breeders may range considerably farther. Areas 

regularly used for foraging covered an area of about 30,000 km2

. Based on these data, it is likely that areas 

used for both murre foraging and seismic surveys will overlap during a portion of the breeding season 

(Figure III.F-3). 

 PEA-68 
Hatch et al. (2000) also determined that breeding murres began to leave their colonies in early September 

and adopted one of two distribution patterns. Most females flew south from the colonies, out of the action 

area. After leaving the colonies, males remained adrift in the Chukchi Sea, and it is thought that they 

remained with the flightless chicks. This scenario could not be confirmed, because the chicks were not 

equipped with satellite transmitters. Several researchers working in other areas have determined that only 

males care for flightless chicks at sea (Scott, 1973; Birkhead, 1976; Harris and Birkhead, 1985; Scott, 

1990). The flightless period for juvenile murres at sea lasts from early September to mid-November when 

they, along with attendant adult males, move quickly to the Bering Sea. During part of this period at sea, 

male murres also molt and are flightless. While these murres were adrift, they drifted north and west 

towards Siberia and averaged 15-20 km/day over a large area of the Chukchi Sea. The general distribution 

of these post-nesting murres is shown in Figure III.F-3. Because the murre distribution during this period 

(early September through mid-November) covers a large area of the Chukchi Sea, it is possible that there 

could be co-location of flightless murres and seismic survey vessels. 

III.F.2.b(1)(b) Puffins. Horned puffins (Fratercula corniculata) are the most abundant puffin species in 

the Chukchi Sea, where around 18,000 breed at colonies at Cape Lisburne and Cape Thompson (Sowls, 

Hatch, and Lensink, 1978). There are about 100 breeding tufted puffins (F. cirrhata) in the same area 

(Sowls, Hatch, and Lensink, 1978). Small numbers of tufted puffins breed at small colonies between Cape 

Thompson and Cape Lisburne. The offshore distance traveled during foraging trips by horned puffins 

breeding at colonies in the Chukchi Sea is unknown, but trips in excess of 100 km have been reported from 

horned puffins in other areas of Alaska, although the breeding status of the satellite-tagged birds was not 

confirmed (Hatch et al., 2000). Horned puffins have been seen near Barrow and have started to breed on 

Cooper Island in the western Beaufort Sea in recent years (Friends of Cooper Island, 2005). Because 

horned puffins are not obligate cliff nesters, they can breed on suitable beach habitat on islands nearshore 

by digging burrows or hiding under large pieces of driftwood or debris. Given their primarily fish-based 

diet and patchy nature of prey items, it is possible that horned puffins have a range similar to murres, 

although the degree to which the foraging areas overlap is unknown. Numbers of horned puffins in the 

Chukchi Sea were greatest in the vicinity of Cape Lisburne after the breeding season in September. 

III.F.2.b(1)(c) Black-legged Kittiwake (Rissa tridactyla). Approximately 48,000 black-legged kittiwakes 

breed along the Chukchi Sea coast between Cape Thompson to Cape Lisburne (USDOI, FWS, 2005). 

These data are more than 25 years old and the current status of the population is unknown. The center of 

the North Pacific breeding range for black-legged kittiwakes is in the Gulf of Alaska and the Bering Sea 

(Sowls, Hatch, and Lensink, 1978); therefore, breeding colonies in the Chukchi Sea are at the northern limit 

of their breeding range in Alaska. Black-legged kittiwakes are common in the Chukchi Sea north of Cape 

Thompson from mid-July until late September, where they range far offshore (Divoky, 1987) through most 

of the action area. From late August to late September, the kittiwake density for the central and southern 

portion of the Chukchi Sea is 2.3 birds/km2

. Divoky (1987) estimated a population in excess of 400,000 

black-legged kittiwakes in the pelagic Chukchi Sea, but the portion of this population in the action area is 

unknown. 

III.F.2.b(2) Bering Sea Breeders and Summer Residents. 

III.F.2.b(2)(a) Northern Fulmar (Fulmarus glacialis). Northern fulmars do not breed in the Chukchi Sea 

and those observed in this area during the summer are non-breeders or failed breeders. When present, 

fulmars are most numerous from late August to mid-September. An estimated 45,000 northern fulmars 

occupy the Chukchi Sea during this period (Divoky, 1987), but this number is relatively small compared 

with an estimated 2.1 million that are present in the Bering Sea in the summer (Gould, Forsell, and 

Lensink, 1982). Divoky (1987) reported that most fulmars in the Chukchi Sea are found in the southern 

portion (latitude south of Cape Lisburne at 68° 45’ N. latitude). 

III.F.2.b(2)(b) Short-tailed Shearwaters (Puffinus tenuirostris). These birds breed in the southern 

hemisphere. In the northern hemisphere, short-tailed shearwaters are found primarily in the Bering Sea, 

where the population was estimated between 20 and 30 million in 1981 by Hunt, Kaiwi, and Schneider 

(1981). Short-tailed shearwaters in the Chukchi Sea are most common in the southern portion, although 

they are routinely found in the central and northern portion, which are in the action area. Short-tailed 

 PEA-69 
shearwaters have been reported as far north as Barrow (71° N. latitude) and beyond (Divoky, 1987), 

depending on the presence of sea ice. At northern latitudes, they likely forage at highly productive patches 

of euphausiids and amphipods. Short-tailed shearwaters are most common in the central and northern 

Chukchi Sea from late August to late September. In certain years, an estimated 100,000 short-tailed 

shearwaters passed Point Barrow in one day in mid-September (Divoky, 1987). This observation is 

consistent with those of Bailey (1948). 

III.F.2.b(2)(c) Auklets. Parakeet (Cyclorrhynchus psittacula), least (Aethia pusilla), and crested (A. 

cristatella) auklets breed as far north as the Bering Strait (Sowls, Hatch, and Lensink, 1978) but move 

north into the Chukchi Sea, including much of the action area, from late August through early October. 

Based on limited data, crested auklets appear to be the most numerous auklet species in the Chukchi Sea 

during this period. In 1986, an anomalous year due to a large intrusion of Bering Sea water into the 

Chukchi Sea that likely affected zooplankton availability, crested auklets were abundant in the Chukchi Sea 

from late August until early October, probably numbering well over 100,000 (Divoky, 1987). The 

distribution in other years is probably less uniform with fewer birds, perhaps 100,000 auklets when 

combining the three species. 

III.F.2.b(3) High-Arctic-Associated Seabirds. 

III.F.2.b(3)(a) Black Guillemot (Cepphus grylle). Roseneau and Herter (1984) estimated 500 breeding 

birds in the Chukchi Sea ranging from Cape Thompson northward. Black guillemots that breed on Cooper 

Island in the Beaufort Sea also make use of the Chukchi Sea in the vicinity of Point Barrow during the 

early part of the breeding season (Divoky, 1987). Despite the relatively small breeding population in 

Alaska (Chukchi and Beaufort seas have a combined total of fewer than 2,000 birds), the pelagic 

population in the Chukchi Sea is estimated to be around 70,000 (Divoky, 1987). It may be that the Alaskan 

breeding and non-breeding population combines with the small (~300) Russian Chukchi population and the 

large (~40,000) nonbreeding population of the East Siberian Sea to forage during the summer near the 

decomposing ice edge in the northern Chukchi Sea (Golovkin, 1984). 

Black guillemots remain closely associated with sea ice throughout their lifetime where they feed 

extensively on arctic cod (Boreogadus saida) (Divoky, 1987). The largest breeding colony in the Beaufort 

Sea is on Cooper Island, where breeding occurs between late June and early September. These guillemots 

make frequent trips to the ice edge to forage on arctic cod, so in the Beaufort Sea they are common within 

their foraging range from Cooper Island. When the sea ice is beyond their foraging range, it appears that 

black guillemots switch prey to other fish species (Friends of Cooper Island, 2005). 

III.F.2.b(3)(b) Ross’ Gull (Rhodostethia rosea). These gulls are rare in the Beaufort Sea during summer, 

because most breed in coastal areas in the Russian Arctic. When present during summer in the Beaufort 

Sea, they typically are found in close association with the ice edge. In September and October, Ross’ gulls 

are common migrants in the western Beaufort Sea, where they occur in greatest concentrations between 

Point Barrow and Tangent Point (near the eastern edge of Elson Lagoon) (Divoky et al., 1988). These few 

weeks in fall are the only time that Ross’ gulls are visible nearshore in Alaska. Very few Ross’ gulls have 

been seen in other areas of the Beaufort Sea. These birds do not overwinter in the Arctic Ocean as once 

thought, and many migrate south through the Chukchi Sea and pass through the Bering Strait to winter in 

the Bering Sea from St. Lawrence Island south along the Kamchatka Peninsula to the Sea of Okhotsk 

(Divoky et al., 1988). 

III.F.2.b(3)(c) Ivory Gull (Pagophila eburnea). Ivory gulls are present in the Beaufort and Chukchi seas in 

limited numbers during fall migration to wintering areas in the northern Bering Sea and are uncommon to 

rare in pelagic waters during summer. Throughout their life cycle they are closely associated with the ice 

edge (Divoky, 1987). 

III.F.2.b(3)(d) Arctic Tern (Sterna paradisaea). Divoky (1983) observed that arctic terns were rare in the 

pelagic waters of the Beaufort Sea. East of Barrow, arctic terns often concentrate while staging, 

presumably to feed on zooplankton. Most arctic terns left the Beaufort Sea by mid-September. While 

common in pelagic waters of the Pacific Ocean on their migration to and from the Southern Hemisphere, 

 PEA-70 
they likely follow a more coastal route out of the Chukchi Sea in the fall, as they are considered rare in 

pelagic waters of the Chukchi (Divoky, 1987). 

III.F.2.b(4) Tundra-Breeding Migrants. 

III.F.2.b(4)(a) Phalaropes. Both red (Phalaropus fulicaria) and red-necked phalaropes (P. lobatus) are 

common in the Chukchi Sea during the open-water periods. Phalaropes are common in pelagic waters as 

well as within a few meters of shore, where their distribution typically is tied to zooplankton abundance. 

Due to their reliance on zooplankton their distribution is patchy, but because they are tied to a moving prey 

source they may be encountered throughout the Chukchi Sea in varying concentrations. Most phalaropes 

are in the Chukchi Sea between the Bering Strait and Point Barrow, and relatively few are found farther 

north. A minimum of 1 million phalaropes are in the Chukchi Sea during summer (Divoky, 1987). 

III.F.2.b(4)(b) Jaegers. Pomarine jaegers (Stercorarius pomarinus), parasitic jaegers (S. parasiticus), and 

long-tailed jaegers (S. longicaudus) are common in the Chukchi Sea in summer until late September, when 

they move south to the Bering Sea. Jaeger densities at sea are thought to be higher in years when there is 

low breeding effort on the tundra. Divoky (1987) estimated 100,000 jaegers in the Chukchi Sea between 

late July and late August. Jaegers were dispersed throughout the Chukchi Sea, with no areas of obvious 

concentration. Jaegers are pelagic seabirds that only come to shore during breeding season. 

III.F.2.b(4)(c) Glaucous Gull (Larus hyperboreus). While some glaucous gulls breed at coastal seabird 

colonies, most breed inland near freshwater (Divoky, 1987; Sowls, Hatch, and Lensink, 1978). Glaucous 

gulls were most common in the Chukchi Sea from late July to late September within 70 km of shore 

between Icy Cape and Barrow. Glaucous gulls typically occur in low densities in the Chukchi Sea, but 

commonly congregate at food sources (Divoky, 1987). 

III.F.2.b(5) Waterfowl. 

III.F.2.b(5)(a) Loons. Pacific loons (Gavia pacifica) are the most common loon species migrating along 

the Chukchi Sea coast, although red-throated (G. stellata) and yellow-billed (G. adamsii) loons are present 

in lesser numbers. Most loons migrate very close to shore during fall migration until they reach the 

Lisburne Peninsula, where they head farther out to sea to head towards the Bering Strait (Divoky, 1987). 

Most of the loon migration takes place in September and, although loons may stop to rest, they are most 

commonly observed in flight as they migrate to southern locations for the winter. 

III.F.2.b(5)(b) Long-tailed Duck. (Clangula hyemalis). During the open-water period when marine 

seismic surveys are possible in the Beaufort Sea, long-tailed ducks are abundant in and near lagoons. In 

late June and early July, most male and nonbreeding female long-tailed ducks assemble in massive flocks 

in lagoons along the Beaufort Sea to molt, while a smaller number molt on large, freshwater lakes. They 

are flightless for a 3- to 4-week period through July and August, but the majority of birds remain in or 

adjacent to the lagoons as opposed to pelagic waters. The molt is an energetically costly time, and longtailed ducks have abundant food resources in the shallow water lagoons (Flint et al., 2003). Breeding 

females molt on freshwater lakes during the last phases of duckling development before departing the 

North Slope in the fall (Johnson and Herter, 1989). 

Long-tailed ducks are common in the Chukchi Sea after the first week of September until late October. 

Typical migration distances offshore for long-tailed ducks as well as other species are shown in Figure 

III.F-4. While most migrate within 45 km of shore (roughly along the 20-m isobath), infrequent 

observations of long-tailed ducks in pelagic waters occur in late September (Divoky, 1987). Most longtailed ducks molt in the lagoons along the Beaufort Sea coast, but they also molt in Kasegaluk Lagoon on 

the Chukchi Sea coast. During the molt, long-tailed ducks tend to stay in or near the lagoons, especially 

near passes between the lagoon and the sea (Johnson, Frost, and Lowry, 1992). 

III.F.2.b(5)(c) Common Eider (Somateria mollissima). Beginning in late June, male common eiders begin 

moving towards molting areas in the Chukchi Sea. Most males are out of the Beaufort Sea by late August 

or early September, and most females were gone by late October or early November. When traveling west 

 PEA-71 
along the Beaufort Sea coast, approximately 90% of the common eiders migrate within 48 km of the coast; 

7% migrate 13-16 km from shore, roughly along the 17- to 20-m isobath (Bartels, 1973) (Figure III.F-4). 

Similarly, Divoky (1983) observed most molt-migrant common eiders traveling westward along a narrow 

corridor within 5 km of the 20-m isobath (13-16 km offshore). Common molt areas in Alaskan waters in 

the Chukchi Sea are near Point Lay, Icy Cape, and Cape Lisburne (Johnson and Herter, 1989). Most 

breeding female common eiders and their young begin to migrate to molt locations in late August and 

September, although large numbers of female common eiders were observed molting in the eastern 

Beaufort Sea in Canada near Cape Parry and Cape Bathurst (Johnson and Herter, 1989). 

In July and August, most common eiders in the Chukchi Sea are molting males. When traveling along the 

northwest coast of Alaska, these eiders tend to stay along the 20-m isobath, approximately 45 km from 

shore. After the molt is completed, some common eiders move offshore into pelagic waters, but the 

majority of eiders remain close to shore (Divoky, 1987). Adult female breeders migrate to molt locations 

in late August and September. 

III.F.2.b(5)(d) King Eider (Somateria spectabilis). Phillips (2005), using satellite telemetry, determined 

that most king eiders spent more than 2 weeks staging offshore in the Beaufort Sea prior to migrating to 

molt locations in the Bering Sea. Females tended to stay for a longer period, possibly to replenish nutrient 

reserves after nesting. Molting king eiders may be encountered in the Beaufort Sea between late June and 

early September. Some king eiders remain in the Beaufort Sea until late fall, where they likely use 

remaining areas of open water (Johnson and Herter, 1989). Prior to molt migration, king eiders in the 

Beaufort Sea usually were found about 13 km offshore but, during migration to molting areas, king eiders 

occupied a wide area ranging from shoreline to >50 km offshore (Phillips, 2005) (Figure III.F-4). Although 

king eiders migrate through the Chukchi Sea, specific observations on their movements are poorly 

understood. Divoky (1987) characterized the movements of all three species of Somateria as typically 

migrating offshore along the 20-m isobath until late September, when they become more common in 

pelagic waters. 

III F.2.c. Impact Assessment.

III.F.2.c(1) Range of Potential Effects. Proposed seismic surveys could have a variety of potential 

impacts to marine birds from the physical presence and noise produced by vessels, sound produced by the 

seismic airguns, and the physical presence and noise produced by support aircraft. Marine birds could be 

exposed to petroleum products in the event of an accidental spill. 

III.F.2.c(1)(a) Disturbances from Vessels, Seismic Airguns, and Support Aircraft.

Vessel Presence and Noise. How waterfowl and marine birds respond to disturbances can vary widely 

depending on the species, time of year, disturbance source, habituation, and other factors (Fox and Madsen, 

1997). It seems that in some species of waterfowl, the distance at which disturbances will be tolerated 

varies depending on flock size, because larger flocks react at greater distances than smaller flocks (Madsen, 

1985). There is an energetic cost to moving away from a disturbance as well as a cost in terms of lost 

foraging opportunities or displacement to an area of lower prey availability. Some sea-duck species (e.g., 

Steller’s eider, long-tailed duck, and harlequin duck [Histrionicus histrionicus]) exhibit different responses 

to different size vessels near developed harbors on the Alaska Peninsula and eastern Aleutian Islands 

during the winter (U.S. Army Corps of Engineers, 2000a,b,c). These species appear to tolerate large, slowmoving commercial vessels passing through narrow channels but typically fly away when in visual distance 

of a fast-moving skiff. Skiffs running small outboard engines at high speed make a distinctive high-pitched 

sound, whereas large commercial vessels produce a lower rumble. As these sea ducks appear more tolerant 

of slow-moving skiffs, their reaction may be interpreted as incorporating aspects of vessel size, speed, and 

engine noise. It also could be that these species associate the small skiffs with hunters they encounter 

elsewhere in their range. Seismic-survey vessels would remain at least 3 mi offshore, so they would not 

come close to nesting areas for any waterfowl or marine birds. It is more likely that vessels might disturb 

waterfowl and marine bids that are foraging or resting at sea or, in the case of a few species, molting at sea. 

 PEA-72 
The seismic-survey activities would not occur in nearshore waters where many marine birds are found. 

Mitigation measures also could reduce vessel and aircraft disturbance to marine birds, especially spectacled 

eiders molting in Ledyard Bay. 

Seismic Airgun Noise. Seismic surveying with airgun arrays results in both vertical and horizontal sound 

propagation. Horizontal propagation is a relevant issue, because it is less likely that marine birds would be 

under the array. Although there is variation in attenuation rates depending on bottom slope and 

composition, sound from airgun arrays can be detected using hydrophones at ranges of 50-75 km in water 

25-50 m deep (Richardson et al., 1995a). 

Very few studies have assessed the effects of seismic surveys on marine birds and waterfowl. Stemp 

(1985) observed responses of northern fulmars, black-legged kittiwakes, and thick-billed murres to seismic 

activities in Davis Strait offshore of Baffin Island. The first 2 years of the study involved the use of 

explosives (dynamite gel or slurry explosives) and, therefore, are not relevant as use of underwater 

explosives is not a method being considered for proposed seismic surveys in the Beaufort and Chukchi 

seas. The final year of the study involved airguns, but the study locations were never in sight of colonies, 

feeding concentrations, or flightless murres. The results of this study did not indicate that seabirds were 

disturbed by seismic surveys using airguns. This conclusion was due in part to natural variation in 

abundance. Nevertheless, Stemp concluded that negative effects from seismic surveys were not anticipated 

as long as activities were conducted away from colonies, feeding concentrations, and flightless murres. 

In the Beaufort Sea, Lacroix et al. (2003) investigated the effects of seismic surveys on molting long-tailed 

ducks. These ducks molt in and near coastal lagoons on the North Slope, primarily during August, during 

which time they are flightless for 3-4 weeks. The molt is an energetically costly period. Long-tailed ducks 

are small sea ducks with higher metabolic rates and lower capacity to store energy than larger ducks 

(Goudie and Ankney, 1986). Consequently, long-tailed ducks need to actively feed during the molt period 

because their energy reserves cannot sustain them during this period (Flint et al., 2003). Lacroix et al. 

(2003) stated there was no clear response by the ducks to seismic surveying, even when the seismic vessels 

were in visual range. However, there may be effects that were too subtle to be detected by this study. The 

presence of long-tailed ducks within several 2.5-km radii of the sound source was monitored, but it was not 

possible to determine short-distance movements in response to seismic activities. Diving behavior of longtailed ducks also was monitored by radio-telemetry, because direct observations may have induced bias due 

to the presence of observers. Therefore, it is unclear whether changes in diving frequency were due to 

disturbance from seismic vessels or local abundance of prey items. For instance, ducks may dive more in 

response to disturbances from vessels or they may dive less to avoid underwater noises related to airguns. 

Further behavioral observations would be necessary to characterize the response of long-tailed ducks to 

seismic surveys, even though the Lacroix et al. (2003) study found no effect of seismic surveying activity 

on movements or diving behavior of long-tailed ducks. 

Seismic airguns have the potential to alter the availability of marine bird prey. Research indicates that 

there are few effects on invertebrates from noise produced by airguns, unless the invertebrate is within a 

few feet of the source (Brand and Wilson, 1996; McCauly, 1994). Consequently, noises from seismic 

airguns are not likely to decrease the availability of invertebrate crustaceans, bivalves, or mollusks. 

It is possible that seismic surveys might affect fish and invertebrates in proximity to the airgun array (see 

discussion in Section III.F.1 Fish/Fishery Resources and Essential Fish Habitat). However, the effects of 

seismic surveys on marine fish that might change their availability to marine birds have not been 

documented under field operating conditions (Canadian Dept. of Fisheries and Oceans [CDFO], 2004d). 

If forage fishes are displaced by airgun noise, birds feeding on those resources might be temporarily 

displaced and stop feeding within a few kilometers of the survey activities. 

It is possible, during the course of normal feeding or escape behavior that some birds could be near enough 

to an airgun to be injured by a pulse. The threshold for physiological damage, namely to the auditory 

system, for marine birds is unknown. Although MMS has no information about the circumstances where 

this might occur, the reactions of birds to airgun noise suggest that a bird would have to be very close to the 

airgun to receive a pulse strong enough to cause injury, if that were possible at all. A mitigation measure to 

 PEA-73 
“ramp-up,” which is a gradual increase in decibel level as the seismic activities begin, can allow diving 

birds to hear the start up of the seismic survey and help disperse them before harm occurs. During ongoing 

surveys, diving birds also are likely to hear the advance of the slow-moving survey vessel and associated 

airgun operations and move away. Mitigation measures to ramp up airguns for use and to document bird 

reactions to seismic-survey vessel activities may help further evaluate the potential for marine birds to be 

harmed by airgun noises. 

Support Aircraft Noise. Aircraft operating at low altitudes may disturb birds that are in the path of the 

aircraft. There is an energetic cost to repeatedly moving away from aircraft disturbances as well as a cost 

in terms of lost foraging opportunities or displacement to an area of lower prey availability. 

Implementation of mitigation measures could reduce the magnitude and frequency of aircraft-related noise 

disturbances to eiders and murrelets. 

III.F.2.c(1)(b) Collisions with Vessels and Aircraft. Migrating birds colliding into manmade structures has 

been well documented in the literature. Weather conditions such as storms associated with rain, snow, 

icing, and fog or low clouds at the time of the occurrences often are attributed as causal factors (Weir, 

1976; Brown, 1993). Lighting of structures, which can be intensified by fog or rain, also has been 

identified as a factor (Avery, Springer, and Dailey, 1980; Brown, 1993; Jehl, 1993). Birds are attracted to 

the lights, become disoriented, and may collide with the light support structure (e.g., pole, tower, or vessel). 

Vessel Strikes. Lights on fishing vessels at sea have been known to attract large numbers of seabirds during 

storms (Dick and Donaldson, 1978). Black (2005) reported a collision of about 900 birds, mostly a variety 

of petrel species and Antarctic prion, with a 75-m fishing trawler near South Georgia. The collisions took 

place over a 6-hour period at night, when visibility was less than 1 nautical mile (nmi) due to fog and rain. 

Of the 900 birds on deck, 215 were dead. Most of the remaining birds were released alive after being 

allowed to dry off in boxes stored in a protected area on deck. Waterfowl and shorebirds also have been 

documented as colliding with lighted structures and boats at sea (Schorger, 1952; Day, Kuletz, and Nigro,

2003). 

Marine birds are at risk of collisions with seismic-survey vessels at night due to attraction and subsequent 

disorientation from high-intensity lights on ships. Sea ducks are vulnerable to collisions with seismicsurvey vessels, primarily because they tend to fly low over the water. Johnson and Richardson (1982) 

documented that 88% of eiders migrating to molting areas along the Beaufort Sea coast flew below an 

estimated 10 m (32 ft) and more than 50% flew below 5 m (16 ft). Eiders (various species) leaving the 

North Slope travel day or night. Movement rates (birds/hour) did not differ between night and day, but 

movement rates and velocities were higher on nights with good visibility (Day et al., 2004). 

Identification and avoidance of marine mammals is an important mitigation measure to prevent harmful 

impacts to marine mammals from seismic surveys. High-intensity lights are needed during the seismic 

surveys to help spot marine mammals during nighttime operations or when visibility is hampered by rain or 

fog. A mitigation measure to not use high-intensity lights when not needed can reduce the potential that 

marine birds would be attracted to and strike the seismic survey vessel. 

Aircraft Strikes. Seismic-survey-support aircraft operating at low altitudes have the potential to flush birds 

into the path of the aircraft where a collision could occur. While such strikes are relatively rare, 

implementation of mitigation measures could further reduce the frequency of strike risk to marine birds. 

III.F.2.c(1)(c) Petroleum Exposure. Coastal and marine birds could be affected by a survey-vessel 

accident resulting in a petroleum spill. However, the potential for a spill is low, given that the vessels will 

be operating at least 3 mi from shore and away from obstructions. In addition, seismic-survey operations 

generally try to stay at least 15 mi away from each other so that they do not interfere with each others’ 

acoustic-generating system. During seismic surveys, vessels will be operating at about 4.5 knots (kn), so 

speeds generally will be slow except for movements between survey areas. Seismic surveys need to be 

conducted in a relatively ice-free environment, so there is only a small chance of damage to survey vessels 

from ice. 

 PEA-74 
Each streamer cable may contain 100-200 L of a paraffin-like, biodegradable fluid to provide buoyancy. 

Newer generation streamer cables are filled with foam and, if used, they would eliminate any risk of a spill 

presented by fluid-filled cables. Breaks in these cables are rare and typically only occur when currents 

whip cables around a structure, such as an oil platform. Seismic surveys in the Beaufort and Chukchi seas 

would be done in open water, far away from structures that would present a risk of entanglement and a 

spill. 

Direct oiling of eiders and murrelets likely would result in loss of feather insulation and acute and chronic 

toxicity from ingestion and absorption. Oiled birds also could carry oil to nests where eggs and young 

could be oiled. 

Both sexes of some marine birds incubate eggs and bring fish for their young. Lightly oiled birds could 

bring oil contamination back to their nest where eggs and young could be contaminated. Lightly oiled 

birds also could also bring contaminated food to the nest. Heavily oiled birds would be prevented from 

returning to the nest, resulting in the young dying of starvation. 

According to oil-spill records, most accidental spills in Alaska happen in harbors or during groundings; 

consequently, a spill from a vessel on the high seas where pelagic murrelets are mostly found in the 

Chukchi Sea would be a rare occurrence. The MMS believes that the risk of incidents involving the release 

of oil and fuel from vessels during seismic-survey activities is likely to be small. This conclusion is based 

on the assumption that there would be no unauthorized discharges from the seismic vessel, such as the 

discharge of engine oil, etc. Therefore, any effects would be due to accidental discharges, such as a spill of 

fuel oil during a fuel transfer from a support vessel to a seismic vessel. The MMS assumes further that the 

operators would be cautious and vigilant during fuel transfers; for example, if a fuel hose broke, the fuel 

valves would be shut off quickly. Given that the risk of incidents likely is small and that the seismic 

surveys typically would be working more than 3 mi from shore, petroleum exposure is not addressed as a 

specific category below. 

III.F.2.c(1)(d) Mitigation Measures. Several methods exist to reduce the potential negative impacts to 

marine birds. The following recommendations could be implemented to mitigate potential negative effects 

on threatened, endangered, and candidate bird species during proposed seismic-survey activities within the 

Proposed Action Area: 

Disturbance: 

• Seismic survey vessels and operations are not permitted within the Ledyard Bay critical habitat 

area (Figure III.F-2). 

• The NMFS and MMS-approved observers would record responses of marine birds and waterfowl 

to seismic-survey operations. Important aspects to record are reaction distances, bird-molting 

status, differences in reaction by flock size, weather conditions, and whether birds moved out of 

the area or returned once the vessel passed by. 

• Seismic-survey-support aircraft would avoid overflights of the Ledyard Bay critical habitat area 

after July 1, unless aircraft are at an altitude in excess of 1,500 ft (~450 m) or unless human safety 

requires a deviation (e.g., a medical emergency). 

Collisions with Vessels or Aircraft: 

• Seismic-survey vessels would minimize operations that require high-intensity work lights inside 

the 20-m bathymetric contour. High-intensity lights should be turned off in inclement weather 

when the vessel is not actively conducting surveys. Navigation lights, deck lights, and interior 

lights should remain on for safety. 

• All bird-vessel collisions would be documented. Minimum information will include species, 

date/time, location, weather, and operational status of survey vessel when the strike occurred. 

Eiders or murrelets injured or killed through collision with survey vessels should be recovered, 

and survey personnel should contact the USDOI, FWS, Fish and Wildlife Field Office, 

 PEA-75 
Endangered Species Branch, Fairbanks, AK, at 907-456-0499 for instructions on the handling and 

disposal of the injured or dead bird. 

• Seismic-survey-support aircraft would maintain at least 1,500 ft (~450 m) over beaches, lagoons, 

and nearshore waters as much as possible. 

The following impact assessments assume these mitigation measures would be fully implemented. 

III.F.2.c(2) Impacts of Alternatives on Threatened and Endangered Species. The level of potential 

impact is based on the alternative selected. 

Alternative 1. The no-action alternative would mean that spectacled and Steller’s eiders and Kittlitz’s 

murrelets in the Beaufort and Chukchi seas would not be exposed to disturbance and noise from seismic 

vessels and associated seismic activities. 

Alternatives 3, 4, 5, and 6. These alternatives differ in how they implement a marine mammal-exclusion 

zone. The marine mammal-exclusion zone is intended to prevent disturbing marine mammals within 

specified zones around the seismic-survey vessel. The zone is monitored using observers that are onboard 

and/or in aircraft. Aircraft or other vessels may be required if the exclusion zone is larger than onboard 

observers can monitor. Mitigation measures could reduce the impacts from aircraft used to monitor the 

exclusion zone. 

Onboard observers would need the use of high-intensity lighting to maintain vigilance for marine mammals 

when the surveys are being conducted during periods of darkness or poor visibility (e.g., during rain or 

fog). Use of high-intensity lighting would be independent of the size of the exclusion zone, as these lights 

would be useful only in areas closest to the seismic-survey vessel. Mitigation measures could reduce the 

impacts from high-intensity lighting. 

II.F.2.c(2)(a) Spectacled Eider. The most likely effects of seismic surveying to spectacled eiders in the 

Beaufort Sea involve disturbance and collisions. 

Disturbances. The potential for disturbance to spectacled eiders is limited to the brief period when females 

depart the tundra after nesting and enter the Beaufort Sea. A variety of tugs and barges already transit 

through the Beaufort and Chukchi seas to supply coastal communities and industries, so the presence of 

seismic-survey ships would represent a small incremental increase in disturbance from vessel traffic. 

The most important issue with disturbance involves the collocation of seismic activities and molting 

spectacled eiders. Male and female spectacled eiders typically take from 1-2 weeks to move from breeding 

grounds on the North Slope to Ledyard Bay. This migration is believed to involve all breeding females as 

well as a portion of males, because some males that breed on the North Slope molt in Russian coastal 

waters. During the couple of weeks between breeding and molting, eiders are at sea, presumably 

replenishing energy reserves before the energetically demanding molt. During this migration, males 

typically migrate within 7 km of the coast and females stay within 17 km; the disparity in distance likely is 

a function of the extent of sea ice (Petersen, Larned, and Douglas, 1999). Due to the extent of sea ice, it is 

unlikely that seismic surveys would begin in the Beaufort Sea when males are passing through and, 

therefore, negative effects are unlikely. Females with broods might be encountered during seismic surveys 

occurring within 17 km of shore between late August and early September. During this migration, eiders 

are able to fly and move away from disturbances, though obviously at some energetic cost. 

In the Chukchi Sea, spectacled eiders molt in Ledyard Bay, an area designated as critical habitat. Males 

and/or females are present in this area from early July through the middle of October or possibly later. 

Regardless of the degree of reliance on exogenous energy reserves during this energetically demanding 

period, spectacled eiders are common in this area and it is probable that energetic needs are a component of 

their molt-site selection. Spectacled eiders will either dive or fly in response to a disturbance. While 

present in Ledyard Bay, these eiders will molt and be flightless for a few weeks, so diving or displacing by 

running and flapping on the surface of the water are the only options to rapidly evacuate an area. There is 

an energetic cost in this behavior as well as a cost in terms of lost foraging opportunities or displacement to 

 PEA-76 
an area of lower prey availability. The magnitude of the effects likely would depend on the frequency and 

timing of the disturbance. In September 1995, approximately 33,000 spectacled eiders were encountered in 

Ledyard Bay; most were located in a 37-km-diameter circle centered approximately 40 km offshore. 

Similar numbers and distributions were observed on other aerial surveys (Petersen, Larned, and Douglas, 

1999). If seismic-survey lines were 500 m apart, as many as 74 transects would be needed to survey the 

Ledyard Bay molting area. With 3D surveys that acquire data using a racetrack pattern, these passes could 

be separated in time, as alternate lines could be surveyed at a fairly distant location before the vessel returns 

to the vicinity of the eiders. This actually may increase impacts to eiders, because it could result in 

repeated disturbances over a longer time period instead of a couple of days of intense local effort. 

Seismic surveys in the Beaufort Sea near a coastal lagoon did not appear to affect the movements or diving 

behavior of molting long-tailed ducks, although the study design did not facilitate detection of more 

localized changes in distribution or diving behavior (Lacroix et al., 2003). It is unknown if spectacled 

eiders might respond in a similar manner. Long-tailed ducks molt in coastal lagoons protected by barrier 

islands, whereas spectacled eiders molt in pelagic waters far from shore. It is possible that the barrier 

islands add a measure of protection from underwater sounds, although most barrier islands in the Beaufort 

Sea provide a poor visual buffer, because they usually are less than a couple of meters above sea level. 

Molting spectacled eiders in Norton Sound dove and resurfaced farther away in response to small skiffs. 

These eiders appeared more wary than other species of sea ducks to the presence of small boats (Larned, 

2006, pers. commun.). Unlike many other species of sea ducks, spectacled eiders have minimal exposure 

to vessels during their lifecycle, as there is minimal exposure on the North Slope, and they winter in 

polynyas south of St. Lawrence Island in the Bering Sea. Accordingly, there is little opportunity for 

habituation to vessel disturbance. Mitigation measures could avoid or minimize vessel disturbance to 

spectacled eiders molting in the Ledyard Bay area. 

Collisions. Eiders flying during low-visibility conditions of rain or fog can strike vessels. Spectacled 

eiders also often migrate at night. Eiders flying at night can become disoriented by high-intensity work 

lights and strike vessels. As day-length decreases during the late summer, eiders migrating to the molting 

area in darkness would be more likely to encounter vessels using high-intensity lights. 

Mitigation measures for marine mammals likely necessitate the use of high-intensity lights at night and 

during inclement weather to search for marine mammals in the vessel path. Seismic surveys would cease 

when the marine mammal-exclusion zone could not be effectively monitored, but the high-intensity lights 

could remain on to search for marine mammals. 

The risk of collisions with spectacled eiders is lowest beyond 60 km offshore, because females tend to 

travel within 60 km and males travel within 35 km. Within these distances from shore, the risk of 

collisions might increase, especially during poor visibility. The greatest risk of a vessel strike would exist 

if the seismic-survey vessel was using high-intensity lighting while transiting through areas of high 

spectacled eider density at night during fog or rain. Implementation of mitigation measures could reduce 

the risk of the seismic-survey vessel operating in eider-concentration areas. 

III.F.2.c(2)(b) Steller’s Eider. The most likely effects of seismic surveys to Steller’s eiders in the Beaufort 

and Chukchi seas involve disturbance and collisions. Due to the extent of sea ice, it is unlikely that seismic 

surveys would begin in the Beaufort Sea when males are passing through, so impacts to Steller’s eiders are 

unlikely. Males could be encountered in the Chukchi Sea in the summer and fall, and females might be 

encountered in both the Beaufort and Chukchi seas during the seismic-survey period. 

Disturbances. The potential for disturbing Steller’s eiders is limited to the brief period when females 

depart the tundra after nesting and move to the Beaufort Sea. Given that seismic surveys would not occur 

within 3 mi of shore and the limited distribution of Steller’s eiders in the Beaufort Sea, effects are unlikely. 

Steller’s eiders spend a relatively small portion of their time in the Alaska Chukchi Sea. Spring migration 

already would be completed prior to seismic-survey activities, because the sea needs to be relatively ice 

free before surveys could begin. Eiders resting and foraging along the Chukchi Sea coast in Alaska could 

 PEA-77 
be disturbed by seismic-survey activities; however, because they molt in other areas of Alaska they would 

be well outside the action area during this energetically demanding period. Due to their low numbers in the 

Chukchi Sea and their tendency to occur within 2 km of shore, it is unlikely that there would be any 

significant adverse effects from disturbance. 

Collisions. Steller’s eiders flying during low-visibility conditions of rain or fog can strike vessels. Steller’s 

eiders flying at night could be attracted to high-intensity lights on vessels, become disoriented, and strike 

the vessel. The numbers of Steller’s eiders that might be affected probably are much lower than for 

spectacled eiders because of the lower abundance of Steller’s eider on the North Slope and the fact that 

they do not molt or otherwise concentrate in the action area. 

III.F.2.c(2)(c) Kittlitz’s Murrelet. Limited data exist on breeding Kittlitz’s murrelets in the action area. 

Breeding pairs in the Chukchi Sea are solitary and nested well inland on the tundra. They forage at sea 

during nesting and chick rearing, but their foraging distances during this period in the Chukchi Sea are 

unknown. In glaciated areas in Alaska, they typically forage within a few hundred meters of shore. In 

Chukotka and the Sea of Okhotsk, they typically forage 200-500 m offshore (Day, Kuletz, and Nigro, 

1999). An estimated 15,000 Kittlitz’s murrelets have been observed in the pelagic waters of the Chukchi 

Sea beginning in late August, but their presence is sporadic, suggesting there are additional factors that 

influence their distribution and that there is large interannual variation in abundance (Divoky, 1987). 

Accordingly, the potential for disturbance from or collision with seismic-survey vessels or aircraft is small. 

The effects of seismic surveys on marine fish that might increase or decrease their availability to marine 

birds have not been documented under field-operating conditions (CDFO, 2004d). If forage fishes are 

displaced by airgun noise, pelagic Kittlitz’s murrelets might be temporarily displaced and stop feeding 

within a few kilometers of the survey activities. 

Kittlitz’s murrelets feed by diving to several meters or more. The murrelets also escape from boats by 

diving when the vessel is close. It is possible, during the course of normal feeding or escape behavior that 

a murrelet could be near enough to an airgun to be injured by a pulse. A mitigation measure to “ramp up” 

airgun noise when seismic surveys begin can help disperse birds before harm occurs. During ongoing 

surveys, murrelets also are likely to hear the advance of the slow-moving survey vessel and associated 

airgun operations and move away. Mitigation measures to document murrelet reactions to seismic-survey 

vessel activities may help further evaluate the potential for marine birds to be harmed by airgun noises. 

III.F.2.c(3) Impacts of Alternatives on Other Marine Birds. The range of potential effects of seismic 

surveys to other marine birds are summarized in the impact assessment section III.F.2.c(1) above. 

III.F.2.c(3)(a) Seabirds. 

Murres. Both species of murres could be disturbed by seismic surveys, primarily during the at-sea rearing 

period when juveniles and molting attendant males are unable to fly. During this period, these birds are 

distributed based on currents covering most of the Chukchi Sea. Data on their distribution during this 

period is based on telemetry data from Hatch et al. (2000). If bird distribution during the period of 

potential seismic surveys is similar to that of the telemetry studies in the mid 1990’s, most murres would be 

outside the action area and would not be disturbed. Because distribution is based on prevailing currents, it 

is possible that the at-sea distribution will remain similar in future years. 

Disturbance at the breeding colonies is unlikely, because survey vessels will not be operating closer than 3 

mi offshore. Foraging bouts can range more than 100 km from shore, but the patchy prey distribution and 

transient nature of seismic surveys is unlikely to lead to disturbance. 

The chance of murres colliding with seismic-survey vessels is relatively low, because most murres should 

be out of the action area during the male molt and at-sea rearing period. The primary risk of collision 

occurs during the brief period when murres migrate south to the Bering Sea. Based on telemetry data 

(Hatch et al., 2000), most murres would not migrate through the action area. 

 PEA-78 
Puffins. Seismic-survey vessels would remain at least 3 mi from shore, so there is little chance for 

disturbance of breeding colonies. Most puffins are located near Cape Lisburne in September, but this area 

represents only a small portion of the action area, and it is possible that this area already might be surveyed 

prior to September. If surveys were completed prior to September, there would be minimal risk of puffins 

colliding with the seismic-survey vessel. 

Black-legged Kittiwake. Disturbance and risk of collision should be minimal to kittiwakes, as they are 

mobile (i.e., not molting) and wide ranging throughout the Chukchi Sea. There are no discernable areas of 

concentration that may increase the impact of disturbance or risk of collision. Most kittiwakes are out of 

the Chukchi Sea by late September. 

Northern Fulmar. If distribution trends are similar to the 1980’s, most fulmars would be south of the 

action area. Furthermore, most fulmars are present in the Chukchi Sea for only a few weeks at the end of 

summer; it is possible that all survey vessels would be working on survey areas farther north during that 

time to take advantage of the period of maximum ice retreat in the Beaufort Sea. Both of these factors 

make the chance of large scale disturbance or collision minimal. 

Short-tailed Shearwaters and Auklets. These species are considered together, because they occur in similar 

numbers and both forage on patchily distributed zooplankton in pelagic waters. The chance of disturbance 

is low, because their distribution is patchy and the disturbance is of short duration. A disturbance might 

lead to a temporary halt in feeding in one area or a switch to a new and possibly less-productive area. 

The risk of collisions is a more relevant issue, as shearwaters and auklets are present in the Chukchi Sea 

until late September or early October. There are about 12 hours of darkness during this period, and seismic 

surveys could occur 24 hours a day. Large collisions involving crested auklets and lights on commercialfishing vessels have been documented; Dick and Donaldson (1978) documented 1.5 metric tons of crested 

auklets striking and nearly capsizing a fishing vessel. Collisions are not documented for shearwaters, but 

these types of events typically are poorly documented. It appears most likely that large collisions occur 

when a combination of darkness, fog, rain, or snow exist and high-intensity lights are used on commercial 

vessels near large aggregations of certain species of seabirds. While there is no certainty that collisions 

would occur, the chance seems to be the greatest for auklets and, perhaps to a lesser extent, shearwaters in 

the Chukchi Sea during seismic surveys. Implementation of mitigation measures would reduce the 

likelihood of collisions. 

Black Guillemot. These birds usually are closely associated with the ice edge, and the likelihood of 

disturbance or collisions is limited to a small portion of the action area. Seismic-survey vessels need to 

follow a specific course during the survey and, therefore, minimize surveys near the ice edge due to the 

presence of large sections of ice that could cause the vessel to alter course or damage seismic instruments. 

Accordingly, operations in areas likely to be inhabited by black guillemots are limited, and the chance for 

disturbance and collisions is minimal. 

III.F.2.c(3)(b) Gulls and Terns. The likelihood of impacts from disturbance or collisions to Ross’ gulls, 

ivory gulls, arctic terns, and glaucous gulls is minimal. Ross’s gulls and ivory gulls are associated with ice 

and breed well outside the action area. They are present in the action area for a short period before 

migrating through the Chukchi Sea to overwintering locations. Arctic terns breed near the coast of both 

seas, but seismic vessels will be operating beyond 3 mi from shore; therefore, disturbance is unlikely. 

Terns migrate through the Chukchi Sea but are rarely observed in pelagic waters. Similarly, glaucous gulls 

typically are most abundant within 70 km of shore, thereby reducing the likelihood of disturbance and 

collisions. 

III.F.2.c(3)(c) Phalaropes. Both species of phalaropes may be encountered in the Beaufort and Chukchi 

seas, especially during the postnesting period in late summer and fall. Phalaropes use habitat within a few 

meters of shore and also pelagic areas; their distribution is generally tied to patchy concentrations of 

zooplankton. Because seismic-survey vessels would remain at least 3 mi offshore, disturbance to or a 

collision with phalaropes nearshore is unlikely. In pelagic waters, disturbances may occur but their impact 

is likely to be minimal, due to the patchy distribution of prey and the transient and short-term nature of 

 PEA-79 
seismic surveys. Disturbed phalaropes might move to another prey patch or return to the same area after 

the disturbance passes. Collisions may occur, especially during inclement weather, but the likelihood of 

collisions is unknown. Lambert (1988) reported that red-necked phalaropes were attracted to lights on a 

ship in the Gulf of Guinea and reacted most strongly at night in inclement weather. There does not appear 

to be any other documented cases of collisions involving phalaropes, so the incidence of collisions may 

either be low or unreported. 

III.F.2.c(3)(d) Jaegers. The chance of impacts to jaegers by disturbance or collision is minimal. Although 

they are present throughout the Chukchi Sea in the fall when there are several hours of darkness and 

frequent inclement weather, jaegers are not known to occur in high concentrations in any area. 

III.F.2.c(3)(e) Waterfowl. 

Loons. In the Beaufort and Chukchi seas, loons typically migrate close to shore until they are south of 

Cape Lisburne, when they travel over pelagic waters on their migration to wintering areas. Impacts from 

disturbances or collisions are unlikely, because loons migrate nearshore in most of the action area, and 

seismic-survey vessels would remain 3 mi offshore. Potential mitigation measures are discussed below that 

might reduce the likelihood of collisions. 

Long-Tailed Ducks. Impacts from disturbances or collisions are unlikely, because long-tailed ducks molt in 

lagoons on the coast of the Beaufort Sea. Seismic-survey vessels would remain 3 mi offshore during 

surveys. This distance is far greater than those encountered during a recent study on the effects of seismic 

surveys on long-tailed ducks in Beaufort Sea lagoons (Lacroix et al., 2003). There was no clear response 

by the ducks to seismic surveying, even when the seismic vessels were in visual range. 

After molting, these birds move south following the Chukchi Sea coast and typically remain 45 km 

offshore along the 20-m isobath. Observations farther offshore are uncommon. The chance of disturbance 

is small due to the small portion of the action area within 45 km from the coast. Collisions are possible, 

especially in inclement weather. Implementation of mitigation measures would reduce the likelihood of 

collisions. 

Common Eider. Impacts to common eiders likely would be similar to those described for spectacled eiders, 

although the implications of potential impacts probably are less significant. Common eiders molt near 

several locations along the Alaska Chukchi Sea coast including Point Lay, Icy Cape, and Cape Lisburne. 

Like spectacled eiders, their molt locations probably coincide with areas of high-density prey items. 

Disturbance at molt locations could impose additional stress during this energetically demanding period; 

the degree of stress would depend on the magnitude and frequency of disturbance. Implementation of 

mitigation measures would minimize the magnitude and frequency of disturbances to common eiders. 

Collisions are possible, especially during nighttime when there is inclement weather. Most common eiders 

follow the 20-m isobath, which is ~45 km from shore in the Chukchi Sea and 13-16 km in the Beaufort 

Sea. Because most of the action area lies well beyond these distances form shore, eiders are at risk of 

collisions for a small portion of the surveys. Implementation of mitigation measures would reduce the 

likelihood of collisions. 

King Eider. Impacts would be similar to common eiders in both the Beaufort and Chukchi seas, except that 

king eiders molt at locations in the Bering Sea. Migration distances from shore are similar, so the collision 

impacts are likely similar to common eiders. Implementation of mitigation measures would reduce the 

likelihood of collisions. 

III.F.2.c(4) Summary of Effects. Potential negative effects of the proposed seismic-survey activities on 

marine birds can be summarized in categories of: 

• Disturbance from the physical presence of vessels; 

• Disturbance from noise by vessels, seismic airguns, and support aircraft; 

• Collision with vessels or aircraft; and 

 PEA-80 
• Direct and indirect results of petroleum product spills from vessels. 

It would be difficult to quantify effects in terms of the number of marine birds potentially affected or areas 

of habitat potentially modified or lost, because the area of the proposed seismic surveys is very large and 

specific knowledge of marine bird distribution and density within the survey area is limited. Consequently, 

a summarization of effects will be in general terms that address the potential effects of prelease seismic 

activities on marine birds within the survey area. 

III.F.2.c(4)(a) Disturbance from the Physical Presence of Vessels. Seismic-vessel activity is expected to 

have only temporary and localized disturbance effects on relatively small numbers of certain marine bird 

species that are distributed in low density over a large action area. Similarly, disturbance to pelagic species 

are expected to be minimal, because they are expected to move away from the slow-moving seismic vessel 

well in advance of the towed seismic- airgun array. Any displacement to these birds is expected to be 

dynamic and temporary. Information collected by onboard observers are anticipated to help document the 

abundance and distribution of key species and to better understand the reaction of key marine bird species 

to seismic survey activities. 

An exception is potential disturbance to spectacled eiders in Ledyard Bay when they gather to molt. In 

Ledyard Bay, repeated disturbance of flightless eiders could move molting eiders near their energetic 

threshold and result in lower than desired fitness for winter survival in the Bering Sea. Implementation of 

additional mitigation measures would prevent or minimize vessel-related disturbances to spectacled eiders 

molting in the Ledyard Bay critical habitat area. 

III.F.2.c(4)(b) Disturbance from Noise by Vessels, Seismic Airguns, and Support Aircraft. Slow-moving 

seismic vessels would be dispersed across the large action area. Seismic activities are dynamic and short 

term in nature. Implementation of mitigation measures largely would avoid and minimize disturbance 

impacts to marine birds in the action area from vessel, airgun, and aircraft noise. 

III.F.2.c(4)(c) Collision with Vessels or Aircraft. Many seabirds can be attracted to lights and vessels in 

nearshore waters. A marine bird striking a vessel could be injured or killed. Potential mortality from being 

attracted to and colliding with seismic-survey vessels is more likely to occur inside the 20-m isobath, where 

the majority of seabirds and waterfowl are believed to migrate. An unknown number of seabirds and 

waterfowl are expected to occasionally be attracted to the lights of seismic vessels during the survey period, 

but implementation of mitigation measures could further reduce risk that birds fly into survey vessels. 

Similar measures outside the 20-m isobath could reduce impacts to more pelagic species. 

III.F.2.c(4)(d) Direct and Indirect Results of Petroleum Product Spills from Vessels. Direct effects of 

contact with oil are loss of insulation; death from hypothermia, exhaustion, or ingestion and absorption; 

transfer of toxicity to eggs and ducklings; and death of eggs and ducklings. 

Indirect affects to marine birds could result from oil spilled when they are or are not present in the survey 

areas. Indirect effects might be contamination of food resources that would lessen the diversity, 

abundance, or caloric value of food resources. Indirect affects on food resources ultimately could affect 

nesting success and overwinter survival. 

A spill in the vicinity of Ledyard Bay during the late June through mid-October molt period (Petersen, 

Larned, and Douglas, 1999) could affect large numbers of flightless spectacled eiders, resulting in 

significant harm to the Arctic Coastal Plain breeding population of spectacled eiders through potential 

stochastic effects. 

Implementing best management practices would make the risk of vessel-related spills in the action area, 

including Ledyard Bay, very small. 

Overall, potential impacts from seismic-survey activities could affect small numbers of low-density marine 

bird species across a large area on a temporary basis. Implementation of mitigation measures is believed to 

reduce direct and indirect impacts to higher density species in concentration areas or in important habitats. 

 PEA-81 
Information collected during the proposed project will aid in updating marine species’ abundance and 

distribution as well as documenting the reaction of key species to seismic-survey activities. 

III.F.3. Threatened and Endangered Species of Marine Mammals.

III.F.3.a. Background. Section 3(15) of the ESA, as amended, states: “(T)he term “species” includes any 

subspecies of fish or wildlife or plants, and any distinct population segment of any vertebrate fish or 

wildlife which interbreeds when mature” (16 U.S.C. § 1532). Thus, under the ESA, distinct population 

segments and subspecies are included along with biological species in the definition of “species,” and such 

entities can be listed separately from other subspecies and/or distinct population segments of the same 

biological species. 

Based on the best available information, and on the guidance provided by the NMFS in their letter of 

September 30, 2005, there are three species of cetaceans that are listed as endangered under the ESA that 

can occur within or near one or both of the Beaufort Sea and Chukchi Sea OCS Planning Areas or that 

could potentially be affected secondarily by activities within these planning areas. The common and 

scientific names of these species are: 

Bowhead whales (Balaena mysticetus) 

Fin whales (Balaenoptera physalus) 

Humpback whales (Megaptera novaeangliae) 

The MMS also informed NMFS that during an informal discussion following a public meeting in January 

2006 in Point Hope, Alaska, MMS staff were told by an Alaskan Native whale hunter that a right whale had 

been harvested relatively recently. The MMS has contacted NMFS’ protected resources staff regarding this 

communication, and the agencies will follow up with the hunter to see if additional information is 

available. We expect to keep NMFS updated on any additional information regarding the potential 

presence of right whales in the Chukchi Sea, and we will follow NMFS’ guidance regarding whether we 

should evaluate the potential for this species to be affected by the Proposed Action. We are unaware of 

other information that indicates that right whales occur in areas that could be affected. 

In the following pages, we also refer to and discuss specific “population stocks” of threatened and 

endangered marine mammal species. The Marine Mammal Protection Act (MMPA) mandates 

management of marine mammal population stocks. Under section 3 of the MMPA, the “...term 

‘population stock’ or ‘stock’ means a group of marine mammals of the same species, or smaller taxa in a 

common spatial arrangement, that interbreed when mature” (16 U.S.C. § 1362 (11)). “Population stock” 

(usually referred to simply as “stock”) designations of many groups of marine mammals have changed over 

the past 2 decades, in large part due to focused efforts to define the stocks coupled with the availability of 

relatively new tools with which to examine patterns of genetic variability from the field of molecular 

genetics. Thus, because of new information, many species of marine mammals that were formerly treated 

as if comprised of only a single stock, now may be subdivided into multiple stocks, or there may be 

discussion of whether multiple stocks exist. In the cases of marine mammals for which separate stocks 

have been delineated, we focus our description and evaluation of potential effects on those stocks that may 

occur within or near the Beaufort Sea or Chukchi Sea OCS Planning Areas. However, we bring in 

information on the biological species as a whole if it enhances the understanding of the relevant stock(s) or 

aids in evaluation of the significance of any potential effects on the stock that occurs within or near these 

areas. 

Because it is clear both from the aforementioned September 30, 2005, letter to MMS from NMFS and from 

our own review that the bowhead whale is the species most likely to be impacted by seismic-survey 

activities in the Beaufort Sea and Chukchi Sea OCS project areas, we provide more detail on this species 

than on fin or humpback whales. Because of their distribution, effects on the other two endangered whale 

species are limited. 

 PEA-82 
III.F.3.b. Summary of Pertinent Information about Listed Species that Underlies our Analyses. 

III.F.3.b(1) Bowhead Whales. There is one ESA-listed species under the jurisdiction of the NMFS, the 

bowhead whale, which regularly seasonally occurs within multiple areas of both the Chukchi Sea and 

Beaufort Sea OCS Planning Areas and which occurs in areas that could be impacted from seismic-survey 

activities. This population stock of bowheads is the most robust and viable of surviving bowhead 

populations and, thus, its viability is critical to the long-term future of the biological species as a whole. 

There is scientific uncertainty about the population structure of bowheads that use the Beaufort and 

Chukchi seas. Data indicate that what is currently referred to as the Western Arctic stock (by NMFS) or as 

the Bering-Chukchi-Beaufort (BCB) Seas stock (by the International Whaling Commission [IWC]) of 

bowheads is increasing in abundance and has increased in abundance substantially since the last ESA 

consultation between MMS and NMFS involving the Chukchi Sea OCS Planning Area. There are 

scientific analyses indicating that BCB Seas bowheads may have reached or are approaching, the lower 

limit of their historic population size. There are related analyses supporting their removal from the list of 

threatened and endangered species. The cause of the historic decline of this species was over-harvesting by 

commercial whalers. The primary known current human-related cause of mortality is a regulated 

subsistence hunt by Alaskan Natives. Conservation concerns include: the introduction of noise and related 

disturbance from existing, but especially potential future, oil and gas activities, shipping, other vessel 

traffic, and hunting in calving, migration, and feeding areas; contamination of their habitat by pollutants 

from planned and potential future oil and gas activity and by other local and distant pollution sources; 

uncertain potential impacts of climate warming; vessel strikes; and entanglement. No data are available 

indicating that, other than historic commercial whaling, any previous human activity has had a significant 

adverse impact on the current status of BCB Seas bowheads or their recovery. The uncertainty of the stock 

structure adds some uncertainty to summaries of the status of bowheads that may be impacted by the 

Proposed Action. Currently available information indicates that bowheads that use the Alaskan Beaufort 

Sea and Chukchi Sea Planning Areas are resilient at least to the level of human-caused mortality and 

disturbance that currently exists, and has existed since the cessation of commercial whaling, within their 

range. Data indicate that at least some bowheads are extremely long lived (100+ years or more), and this 

longevity can affect the potential for a given individual to be exposed to a high number of disturbance and 

pollution events in its lifetime. Within or near areas where the Proposed Actions could occur, geographic 

areas of particular importance to this stock include the areas of the spring lead system in both the Chukchi 

and Beaufort seas and areas that are used for feeding by large numbers of individuals in some years, but not 

in all years. Available information indicates that most or much of the total calving of the bowheads, which 

comprise most of the bowhead whales in the world, occurs during the spring migration in, and adjacent to, 

especially the eastern Chukchi Sea and also the Beaufort Sea spring lead systems. Features of the 

bowhead’s biology that particularly influence potential effects on this species from the Proposed Action are 

its dependence on the lead system as its migratory pathway between wintering and summering grounds and 

its extreme longevity. Recent data to evaluate bowhead use of the Chukchi Sea OCS Planning Area, or 

adjacent areas to the south, are lacking. 

III.F.3.b(2) Fin Whales. Fin whales may occur seasonally in the southwestern Chukchi Sea, north of the 

Bering Strait along the coast of Chukotka. Their known current summer feeding habitat includes the 

southern portion, especially the southwestern portion, of the Chukchi Sea along the Asian coast. This 

species’ current use of parts of its range probably is modified due to serious population reduction during 

commercial hunting. However, there is no indication that fin whales typically occur within the Chukchi 

Sea project area or in areas directly adjacent to that area, or that they will tend to occur there even if full 

population recovery occurs. There have been only rare observations of fin whales into the eastern half of 

the Chukchi. Data indicate they do not typically occur in the northeast Chukchi Sea, and this species has 

not been observed in the Alaskan Beaufort Sea. The NMFS has concluded that there is no reliable 

information about population-abundance trends, and that reliable estimates of current or historical 

abundance are not available, for the entire Northeast Pacific fin whale stock. Fin whales are a widely 

distributed species. Ranges of population estimates from the 1970’s for the entire North Pacific are 14,620-

18,630 (Ohsumi and Wada, 1974). There are no recent data to confirm their lack of use of the Chukchi Sea 

OCS Planning Area, or adjacent areas to the south. 

 PEA-83 
III.F.3.b(3) Humpback Whales. The northern Bering Sea, Bering Strait, and southern Chukchi Sea along 

the Chukchi Peninsula are the northern extreme of the range of the humpback whale. Their known current 

summer feeding habitat includes the southern portion, especially the southwestern portion, of the Chukchi 

Sea. Historically, large numbers of humpbacks were seen feeding near Cape Dezhnev. Humpback whale 

use of portions of their range also has been influenced by their severe population reduction due to historic 

commercial hunting. Available information does not indicate humpback whales inhabit the Chukchi Sea or 

Beaufort Sea OCS project areas. There are no recent data to confirm their lack of use of the Chukchi Sea 

OCS Planning Area, or adjacent areas to the south. 

III.F.3.c. Bowhead Whale. 

III.F.3.c(1) Introduction. Information provided in this section provides, updates and, in some cases, 

summarizes information from the Beaufort Sea multiple-sale EIS (USDOI, MMS, 2003a), the Biological 

Evaluation for Lease Sale 195, and the environmental assessment for Lease Sale 195 (USDOI, MMS, 

2004) and supplements this information with more recent information on the Western Arctic stock of the 

bowhead whale. All available information is considered in our update of our analyses of the potential 

effects of the Proposed Action on bowhead whales. Additionally, we provide an update of baseline 

information and information related to evaluating potential cumulative anthropogenic impacts on this 

population, as defined under the ESA. As noted in the beginning of this document, we incorporate by 

reference all information provided previously in the Beaufort Sea multiple-sale final EIS, which provided a 

detailed evaluation of the bowhead whale and its habitat, the potential effects of three lease sales in the 

Beaufort Sea Planning Area and related activities on this stock of whales, and an evaluation of cumulative 

effects on this population stock. 

The NMFS issued their Biological Opinion on Issuance of Annual Quotas Authorizing the Harvest of 

Bowhead Whales to the Alaska Eskimo Whaling Commission for the Period 2003 through 2007 (NMFS, 

2003a). Relatedly, in February 2003 the NMFS published the Final Environmental Assessment for Issuing 

Subsistence Quotas to the Alaska Eskimo Whaling Commission for a Subsistence Hunt on Bowhead Whales 

for the Years 2003 through 2007 (NMFS, 2003b). The USDOC NOAA and the North Slope Borough 

(NSB) convened the first Workshop on Bowhead Whale Stock Structure Studies in the Bering-ChukchiBeaufort Seas: 2005-2006 (USDOC, NOAA and NSB, 2005). The second meeting of this group is 

scheduled for spring 2006. The Scientific Committee of the IWC reviewed and critically evaluated new 

information available on the bowhead whale at their 2003 and 2005 meetings (IWC, 2003a; IWC, 2005a,b) 

and conducted an in-depth status assessment of this population in 2004 (IWC, 2004a,b). The MMS 

published Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 2002-2004 (Monnett and Treacy, 

2005). The Final 2003 Alaska Marine Mammal Stock Assessment (Angliss and Lodge, 2003) for this stock 

remains the most recent finalized stock assessment available, as no stock assessment was finalized in 2004. 

There is a revised draft stock assessment for 2005 available for this population (Angliss and Outlaw, 2005). 

The NMFS published the Notice of Determination - Endangered and Threatened Species; Final 

Determination on a Petition to Designate Critical Habitat for the Bering Sea Stock of Bowhead Whales (67 

FR 55767). Details on bowheads that might lie outside the scope of the material provided here, in our 

multiple-sale EIS, or in our EA for proposed Lease Sale 195, may be provided in one or more of these 

documents. We have reviewed and considered information in these documents and other available 

information in our evaluation of potential environmental impacts. 

III.F.3.c(2) ESA Status of the Western Arctic Stock. The bowhead whale was listed as endangered on 

June 2, 1970. No critical habitat has been designated for the species. The NMFS received a petition on 

February 22, 2000, requesting that portions of the U.S. Beaufort and Chukchi seas be designated as critical 

habitat for the Western Arctic stock (Bering Sea stock) of bowhead whales. On August 30, 2002, the 

NMFS made a determination not to designate critical habitat for this population of bowheads (67 FR

55767) because: (1) the population decline was due to overexploitation by commercial whaling, and 

habitat issues were not a factor in the decline; (2) the population is abundant and increasing; (3) there is no 

indication that habitat degradation is having any negative impact on the increasing population; and (4) 

existing laws and practices adequately protect the species and its habitat. 

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All available information (e.g., Shelden et al., 2001; IWC, 2004a,b; IWC, 2005a,b; NMFS, 2003a,b); 

indicates that the BCB Seas population of bowheads is increasing, resilient to the level of mortality and 

other adverse effects that are currently occurring due to the subsistence hunt or other causes, and may have 

reached the lower limit of the estimate of the population size that existed prior to intensive commercial 

whaling. 

Shelden et al. (2001) proposed that the bowhead whale species should be listed under the ESA as five 

distinct population segments, based on the distinct population segment definition developed by the NMFS 

and FWS in 1996. The five separate stocks of bowhead whales are the Bering Sea stock (referred to in 

IWC documents as the BCB Seas bowhead and as the Western Arctic stock in the NMFS’ Alaska Marine 

Mammal stock assessments), the Spitsbergen stock, the Davis Strait stock, the Hudson Bay stock, and the 

Okhotsk stock. Shelden et al. (2001) evaluated each proposed distinct population segment to determine 

whether one or more should be reclassified. The authors presented two models to evaluate the status of 

bowhead whale stocks, one that they developed based on World Conservation Union criterion D1 and E 

(World Conservation Union, 1996, as referenced in Shelden et al., 2001), and a model developed by Gerber 

and DeMaster (1999) for ESA classification of North Pacific humpback whales. Under each of these 

classification systems, the authors determined that the Bering Sea population of bowhead whales should be 

delisted, whereas the other four populations of bowheads should continue to be listed as endangered (see 

also criticism of this determination by Taylor, [2003], the response of Shelden et al. [2003] and discussion 

by the IWC’s Scientific Committee [IWC, 2003a]). 

III.F.3.c(3) Population Structure and Current Stock Definitions. The IWC currently recognizes five 

stocks of bowheads for management purposes (IWC, 1992), with one of them being the BCB Seas stock. 

The BCB Seas bowheads are the largest of all surviving bowhead populations and the only stock to inhabit 

U.S. waters. All of the stocks except for the BCB Seas bowhead stock are “comprised of only a few tens to 

a few hundreds of individuals” (Angliss and Outlaw, 2005:209). Thus, the BCB Seas bowheads are the 

most robust and viable of surviving bowhead populations. The viability of bowheads in the BCB Seas 

stock is critical to the long-term future of the biological species as a whole. 

The Scientific Committee of the IWC previously concluded that the BCB Seas bowheads comprise a single 

stock (DeMaster et al., 2000, as cited in IWC, 2003a). However, after an in-depth evaluation of available 

data, the Scientific Committee (IWC, 2004a) concluded that there is temporal and spatial heterogeneity 

among these bowheads, but analyses do not necessarily imply the existence of subpopulations with limited 

interbreeding; it was premature to draw conclusions about the relative plausibility of any hypotheses about 

stock structure or to reject any of them. Subsequently, “The Bowhead Group” (USDOC, NOAA and NSB, 

2005) created a set of five stock-structure hypotheses, modified this set, and currently recommends testing 

of the following hypotheses: (1) one stock of BCB Seas bowheads as described and previously accepted by 

the IWC (Rugh et al., 2003); (2) one stock with generational gene shift; (3) temporal migration—there are 

two stocks and two putative wintering area, with the two stocks migrating separately in the spring but 

together in the fall; (4) segregation of stocks; spatial segregation of stocks; and (5) Chukchi Circuit—one 

population migrates from the Bering Sea to the Beaufort Sea in spring and back again in the fall, whereas 

the second leaves the Bering Sea, heads northwest along the Chukotka coast, heads towards the Barrow 

Canyon and then back to the Bering Sea (see USDOC, NOAA and NSB, 2005 for detailed descriptions and 

discussions). After more recent information provided to the IWC Subcommittee on Bowhead, Right and 

Gray Whales (IWC, 2005b), the subcommittee agree that what is termed the “Oslo Bump” (a significant 

increase in genetic difference between pairs of whales sampled approximately 1 week apart at Barrow 

during the fall migration) appears to be a real pattern within the data that are available. Additional data are 

needed to determine if these data actually typify the bowhead population, and there is no single hypothesis 

adequate to explain the pattern. Stock structure is unclear at the time of this writing (see IWC, 2004b; 

2005a,b; USDOC, NOAA and NSB, 2005 for detailed descriptions and discussions). The IWC will be 

conducting an Implementation Review focusing on the stock structure of the BCB Seas bowhead with the 

goal of completing this at the 2007 annual meeting (IWC, 2005a). Two related intersessional workshops, 

one that occurred in 2005 and one that will occur in spring 2006, are focusing on this topic (IWC, 2005a,b). 

The uncertainty about the stock structure of bowheads that inhabit the Chukchi and Beaufort seas adds 

uncertainty to the analysis of potential effects. It is not currently clear whether one or more population 

 PEA-85 
stocks of bowheads potentially could be impacted by the proposed activities. If more than one population 

may be affected, it may be that the areas in which the two stocks are likely to be vulnerable to adverse 

effects varies. If there is more than one stock, it is not clear what the estimated population sizes of the 

potentially affected population stocks are. 

III.F.3.c(4) Past and Current Population Abundance. Woody and Botkin (1993) estimated that the 

historic population abundance of bowheads in the Western Arctic stock was between 10,400 and 23,000 

whales in 1848 before the advent of commercial whaling, which severely depleted bowhead whales. They 

estimated that between 1,000 and 3,000 animals remained in 1914 near the end of the commercial-whaling 

period. 

Based on both survey data and the incorporation of acoustic data, the abundance of the Western Arctic 

stock of bowhead whales was estimated between 7,200 and 9,400 individuals in 1993 (Zeh, Raftery, and 

Schaffner, 1995), with 8,200 as the best population estimate. This estimate was recently revised by Zeh 

and Punt (2004) to 8,167 (CV= 0.017) and is the estimate used by the NMFS in their draft 2005 stock 

assessment (Angliss and Outlaw, 2005). An alternative method produced an estimate of 7,800 individuals, 

with a 95% confidence interval of 6,800-8,900 individuals. Data indicate that the Western Arctic stock 

increased at an estimated rate of about 3.1% (Raftery, Zeh, and Givens, 1995) to 3.2% (Zeh, Raftery, and 

Schaffner, 1995) per year from 1978-1993. The estimated increase in the estimated population size most 

likely is due to a combination of improved data and better censusing techniques, along with an actual 

increase in the population. 

George et al. (2004) estimated abundance in 2001 to be 10,470 (SE = 1,351) with a 95% confidence 

interval of 8,100-13,500. This estimate indicates a substantial increase in population abundance since 1993 

and suggests that population abundance may have reached the lower limits of the historical population 

estimate. Zeh and Punt (2004, cited in Angliss and Outlaw, 2005) provided a slightly revised population 

estimate of 10,545 CV(N) =0,128 to the IWC in 2004. George et al. (2004) estimated that the annual rate 

of increase (ROI) of the population from 1978-2001 was 3.4% (95% CI 1.7%-5%) and Brandon and Wade 

(2004) estimate an ROI of 3.5% (95% CI 2.2-4.9%). The number of calves (121) counted in 2001 was the 

highest ever recorded for this population and this fact, when coupled with the estimated rate of increase, 

suggests a steady recovery of this population (George et al., 2004). This steady recovery is likely due to 

low anthropogenic mortality, a relatively pristine habitat, and a well-managed subsistence hunt (George et 

al., 2004). 

III.F.3.c(5) Reproduction, Survival and Non-Human Sources of Mortality. Information gained from the 

various approaches at aging BCB Seas bowhead whales and estimating survival rates all suggest that 

bowheads are slow-growing, late-maturing, long-lived animals with survival rates that are currently high 

(Zeh et al, 1993; see below). Female bowheads probably become sexually mature at an age exceeding 15 

years, from their late teens to mid-20’s (Koski et al., 1993) (Schell and Saupe, 1993: about 20 years). 

Their size at sexual maturity is about 12.5-14.0 m long, probably at an age exceeding 15 years (17-29 

years: Lubetkin et al., 2004, cited in IWC, 2004b). Most males probably become sexually mature at about 

17-27 years (Lubetkin et al., 2004, cited in IWC, 2004b). Schell and Saupe (1993) looked at baleen plates 

as a means to determine the age of bowhead whales and concluded that bowheads are slow-growing, taking 

about 20 years to reach breeding size. Based on population structure and dynamics, Zeh et al. (1993) also 

concluded that the bowhead is a late-maturing, long-lived animal (George et al., 1999) with fairly low 

mortality. Photographic recaptures by Koski et al. (1993) also suggested advanced age at sexual maturity 

of late teens to mid-twenties. 

Mating may start as early as January and February, when most of the population is in the Bering Sea but 

has also been reported as late as September and early October (Koski et al., 1993). Mating probably peaks 

in March-April (IWC, 2004b). Gestation has been estimated to range between 13 and 14 months (Nerini et 

al., 1984, as reported in Reese et al., 2001; Reese et al., 2001) and between 12 and 16 months by Koski et 

al. (1993) (see also information and discussion in IWC, 2004b). Reese et al. (2001) developed a nonlinear 

model for fetal growth in bowhead whales to estimate the length of gestation, with the model indicating an 

average length of gestation of 13.9 months. Koski et al. (1993) reported that calving occurs from March to 

early August, with the peak probably occurring between early April and the end of May (Koski et al., 

1993). The model by Reese et al. (2001) also indicated that conception likely occurs in early March to 

 PEA-86 
early April, suggesting that breeding occurs in the Bering Sea. The conception date and length of gestation 

suggests that calving is likely to occur in mid-May to mid-June, when whales are between the Bering Strait 

and Point Barrow (in the Chukchi Sea). Reese et al. (2001) said this is consistent with other observations in 

the region, including: (a) relatively few neonate-cow pairs reported by whalers at St. Lawrence Island; (b) 

many neonates seen during the whale census in late May; (c) relatively few term females taken at Barrow; 

(d) taken females with term pregnancies appeared close to parturition; and (e) most of the herd believed to 

have migrated past Barrow by late May. Females give birth to a single calf probably every 3-4 years. 

Discussion during the in depth assessment by the IWC (2004b) also indicated that differences in lipid 

content between females of the same length and size are attributable to pregnant versus nonpregnant 

females. This may imply a high biological cost of reproduction, a fact noteworthy in considering the 

potential impact of excluding females from feeding areas. George et al. (2004, cited in IWC, 2004b) 

estimated pregnancy rates of 0.333/year and an estimated interbirth interval of 3.0 years using data from 

postmortem examinations of whales landed at Barrow and Kaktovik in the winter. 

There is little information regarding causes of natural mortality for BCB Seas bowhead whales. Bowhead 

whales have no known predators except, perhaps, killer whales and subsistence whalers. The frequency of 

attacks by killer whales probably is low (George et al., 1994). A relatively small number of whales likely 

die as a result of entrapment in ice (Philo et al., 1993). Little is known about the effects of microbial or 

viral agents on natural mortality. 

The discovery of traditional whaling tools recovered from five bowheads landed since 1981 (George et al., 

1995) and estimates of age using aspartic-acid racemization techniques (George et al., 1999) both suggest 

bowheads can live a very long time, in some instances more than 100 years. The oldest harvested females 

whose ages were estimated using corpora albicans accumulation to estimate female age were > 100 years 

old (George et al., 2004, cited in IWC, 2004b). Discussion in the IWC (2004b) indicated that neither 

lifespan nor age at sexual maturity is certain. Lifespan may be greater than the largest estimates. 

Using aerial photographs of naturally marked bowheads collected between 1981 and 1998, Zeh et al. 

(2002:832) estimated “the posterior mean for bowhead survival rate...is 0.984, and 95% of the posterior 

probability lies between 0.948 and 1.” They noted that a high estimated survival rate is consistent with 

other bowhead life-history data. 

III.F.3.c(6) Migration, Distribution, and Habitat Use. As available information permits, we provide 

detailed summary and discussion about the migration, distribution, and habitat use of bowheads to provide 

insight into areas where bowheads might be exposed to seismic survey activities, when they might be 

exposed, and what the significance of their exposure in certain geographic areas might be relative to that in 

other areas. We include information, as available, about female with calves. This aids our evaluation of 

potential effects and informs potential mitigations of effects. 

The BCB Seas bowheads generally occur north of 60° N. latitude and south of 75° N. latitude (Angliss and 

Outlaw, 2005) in the Bering, Chukchi, and Beaufort seas. They have an affinity for ice and are associated 

with relatively heavy ice cover and shallow continental shelf waters for much of the year. 

III.F.3.c(6)(a) Winter and Other Use of the Bering Sea. Bowhead whales of the BCB Seas stock currently 

overwinter in the central and western Bering Sea. Most mating probably occurs in the Bering Sea. The 

amount of feeding in the Bering Sea in the winter is unknown as is the amount of feeding in the Bering 

Strait in the fall (Richardson and Thomson, 2002). In the Bering Sea, bowheads frequent the marginal ice 

zone, regardless of where the zone is, and polynyas. Important winter areas in the Bering Sea include 

polynyas along the northern Gulf of Anadyr, south of St. Matthew Island, and near St. Lawrence Island. 

Bowheads congregate in these polynyas before migrating (Moore and Reeves, 1993). 

Observations by Mel’nikov, Zelensky, and Ainana (1997) from shore-based observations of waters 

adjacent to the Chukotka Peninsula in 1994-1995 indicate that bowheads winter in the Bering Sea along 

leads and polynyas adjacent to the Asian coastline. Mel’nikov, Zelensky, and Ainana (1997) summarized 

 PEA-87 
that in years when there is little winter ice, bowheads inhabit the Bering Strait and potentially inhabit 

southern portions of the Chukchi Sea. 

During their southward migration in the autumn, bowheads pass through the Bering Strait in late October 

through early November on their way to overwintering areas in the Bering Sea. Large numbers of 

bowheads were taken in June and July during commercial whaling over large portions of the northwestern 

and northcentral Bering Sea (Dahlheim et al., 1980:Figure 1b, from Townsend, 1935). 

III.F.3.c(6)(b) Spring Migration. Some, or nearly all, (see stock discussion above) of the bowheads that 

winter in the Bering Sea migrate northward through the Bering Strait to the Chukchi Sea and through the 

Alaskan Beaufort Sea to summer feeding grounds in the Canadian Beaufort Sea. The bowhead northward 

spring migration appears to coincide with ice breakup and probably begins most years in April (possibly 

late March depending on ice conditions) and early May. It is thought to occur after the peak of breeding, 

which is believed to occur in March-April (C. George, cited in IWC, 2004b). 

Bowheads congregate in the polynyas before migrating (Moore and Reeves, 1993; Mel’nikov, Zelensky, 

and Ainana, 1997). Large numbers of bowheads were taken in June and July during commercial whaling 

over large portions of the northwestern and northcentral Bering Sea (Dahlheim et al., 1980:Figure 1b, from 

Townsend, 1935). Bowheads migrate up both the eastern and western sides of the Bering Strait in the 

spring (Mel’nikov, Zelensky, and Ainana, 1997; Mel’nikov et al., 2004). They pass through the Bering 

Strait and eastern Chukchi Sea from late March to mid-June through newly opened leads in the shear zone 

between the shorefast ice and the offshore pack ice. During spring aerial surveys in the late 1980’s, 

bowheads were documented to be migrating in shorefast leads and polynyas up the coast of northwestern 

Alaska (Mel’nikov, Zelensky, and Ainana, 1997:Figures 4 and 5). 

Based on shore-based surveys in 1999-2001, Mel’nikov et al. (2004) observed that the start of spring 

migration from the Gulf of Anadyr varies between cold and mild years by up to 30 days, but in both 

instances, continues at least until June 20. Mel’nikov et al. (2004) also reported that weather influenced 

migration, with migration seeming to stop when there were storms or high winds in the western Bering 

Strait or at the exit from the Gulf of Anadyr. 

The migration past Barrow takes place in pulses in some years (e.g., in 2004) but not in others (e.g., 2003) 

(Koski et al., 2004, cited in IWC, 2004b). At Barrow, the first migratory pulse is typically dominated by 

juveniles. This pattern gradually reverses and by the end of the migration, there are almost no juveniles. 

Currently, the whales are first seen at Barrow around April 9-10. In later May (May 15-June), large whales 

and cow/calf pairs are seen (H. Brower, in USDOC, NOAA and NSB, 2005; IWC, 2004b). Koski et al. 

(2004) found that cow/calf pairs constituted 31-68% of the total number of whales seen during the last few 

days of the migration. Their rate of spring migration was slower and more circuitous than other bowheads. 

Calves had shorter dive duration, surface duration, and blow interval than their mothers. Calf blow rate 

was nearly 3 times that of their mothers. Most calving probably occurs in the Chukchi Sea. Some 

individuals or subset of the population may summer in the Chukchi Sea. 

Several studies of acoustical and visual comparisons of the bowhead’s spring migration off Barrow indicate 

that bowheads also may migrate under ice within several kilometers of the leads. Data from several 

observers indicate that bowheads migrate underneath ice and can break through ice 14-18 cm (5.5-7 in) 

thick to breathe (George et al., 1989; Clark, Ellison, and Beeman, 1986). Bowheads may use cues from 

ambient light and echoes from their calls to navigate under ice and to distinguish thin ice from multiyear 

floes (thick ice). After passing Barrow from April to mid-June, they move easterly through or near 

offshore leads. East of Point Barrow, the lead systems divide into many branches that vary in location and 

extent from year to year. The spring-migration route is offshore of the barrier islands in the central Alaskan 

Beaufort Sea. 

III.F.3.c(6)(c) Summer Migration. Bowheads arrive on their summer feeding grounds near Banks Island 

from mid-May through June (July: IWC, 2005b) and remain in the Canadian Beaufort Sea and Amundsen 

Gulf until late August or early September (Moore and Reeves, 1993). Bowhead whales are seen also in the 

central Chukchi Sea and along the Chukotka coast in July and August. They may occupy the northeastern 

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Chukchi Sea in late summer more regularly than commonly believed (Moore, 1992; USDOC, NOAA, and 

NSB, 2005), but it is unclear if these are “early-autumn” migrants or whales that have summered nearby 

(Moore et al., 1995) or elsewhere. Bowhead whales have been observed near Barrow in the mid-summer 

(e.g., Brower, as cited in USDOI, MMS, 1995a). Eight bowheads were observed near Barrow on July 25, 

1999, 2 at 71° 30’ N. latitude, 155° 40’W. longitude to 155° 54’ W. longitude from a helicopter during a 

search, and six at 71° 26’ N. latitude, 156° 23’ W. longitude from the bridge of the icebreaker Sir Wilfrid 

Laurier (Moore and DeMaster, 2000). Moore and DeMaster (2000:61) noted that these observations are 

consistent with Russian scientist suggestions that “...Barrow Canyon is a focal feeding area for bowheads 

and that they ‘move on’ from there only when zooplankton concentrations disperse (Mel’nikov et al., 

1998)” and consistent with the time frame of earlier observations summarized by Moore (1992). 

Some biologists conclude that almost the entire Bering Sea bowhead population migrates to the Beaufort 

Sea each spring and that few whales, if any, summer in the Chukchi Sea. Incidental sightings suggest that 

bowhead whales may occupy the Chukchi Sea in the summer more regularly than commonly believed. 

Moore (1992) summarized observations of bowheads in the northeastern Chukchi in late summer. Other 

scientists maintain that a few bowheads swim northwest along the Chukotka coast in late spring and 

summer in the Chukchi Sea. Observation by numerous Russian authors (cited in Mel’nikov, Zelensky, and 

Ainana [1997:8]) indicates that bowheads occur in waters of the Chukchi Sea off the coast of Chukotka in 

the summer. 

Although records of bowhead sightings from 1975-1991 suggest that bowheads may occur along Alaska’s 

northwestern coast in late summer, no one has yet established that these are “early-autumn migrants” or 

whales that have summered nearby (Moore et al., 1975). Harry Brower, Jr. observed whales in the Barrow 

area in the middle of the summer, when hunters were hunting bearded seals on the ice edge (Brower, as 

cited in USDOI, MMS, 1995a). The monitoring program conducted while towing the single steel drilling 

caisson to the McCovey location in 2002 recorded five bowhead whales off Point Barrow on July 21. 

Recent systematic data about bowhead distribution and abundance in the Chukchi Sea OCS Planning Area 

are lacking. The MMS funded large-scale surveys in this area when there was oil and gas leasing and 

exploration, but while surveys in the Beaufort Sea have continued, the last surveys in the Chukchi Sea were 

about 15 years ago. These data were summarized by Mel’nikov, Zelensky, and Ainana (1997), Moore 

(1992), Moore and Clarke (1990), and Moore, DeMaster, and Dayton (2000). We have plotted counts of 

bowheads in the Chukchi Sea during those surveys (Figure III.F-7), because they visually provide limited 

insight into areas where bowheads may be exposed to oil and gas activities should they occur in the 

Chukchi Sea Planning Area. However, we caution against over-interpretation of these data out of context 

of survey effort and, because these data were collected between 1979 and 1991, they should not be 

interpreted as indicating current use of the Chukchi Sea by bowhead whales; they are the best data 

available. 

Bowheads found in the Bering and Chukchi seas in the summer may be part of the expanding Western 

Arctic stock (DeMaster et al., 2000, as referenced in Angliss, DeMaster, and Lopez, 2001). Evidence 

indicates that the number of bowheads that inhabit the BCB Seas has increased substantially since the time 

of the surveys (Brandon and Wade, 2004, cited in IWC, 2004b) in the Chukchi Sea. Temporal and spatial 

patterns of distribution also may be modified. Conversely, earlier information may have inferred less 

variability in distribution than actually existed. 

III.F.3.c(6)(d) Fall Habitat Use and Migration. Those bowheads that have been summer feeding in the 

Canadian Beaufort Sea begin moving westward into Alaskan waters in August and September. While few 

bowheads generally are seen in Alaskan waters until the major portion of the migration takes place 

(typically mid-September to mid-October), in some years bowheads are present in substantial numbers in 

early September (Greene and McLennan, 2001; Treacy, 1998). In 1997, Treacy (1998) reported sighting 

170 bowheads, including 6 calves, between Cross Island and Kaktovik on September 3 during the first 

flight of the survey that year. In 1997, Treacy (1998) observed large numbers of bowheads between 

Barrow and Cape Halkett in mid-September. Large numbers were still present between Dease Inlet and 

Barrow in early October (although they may not have been the same individuals). 

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There is some indication that the fall migration, just as the spring migration, takes place in pulses or 

aggregations of whales (Moore and Reeves, 1993). Inupiat whalers report that smaller whales precede 

large adults and cow-calf pairs on the fall migration (Braham et al., 1984, as reported in Moore and Reeves, 

1993). During the autumn migration Koski and Miller (2004, cited in IWC, 2004b) found decreasing 

proportions of small whales and increasing proportions of large whales as one moved offshore. “Mothers 

and calves tended to avoid water depths <20 m.” (Koski and Miller, cited in IWC, 2004b:14). These 

authors also found that in the Central Beaufort Sea in late August, the vast majority of the whales were 

subadults and this percentage declined throughout the autumn to about 35% by early October. They 

reported that mother/calf pairs “arrived in September and were common until early October” (Koski and 

Miller, 2004, cited in IWC, 2004b). 

Inupiat whalers estimate that bowheads take about 2 days to travel from Kaktovik to Cross Island, reaching 

the Prudhoe Bay area in the central Beaufort Sea by late September, and 5 days to travel from Cross Island 

to Point Barrow (T. Napageak, 1996, as cited in NMFS, 1999). 

Individual movements and average speeds (approximately 1.1-5.8 km/hour) vary widely (Wartzog et al., 

1990; Mate, Krutzikowsky, and Winsor, 2000). Much faster speeds (e.g., up to 9.8 + 4.0 km/hour) were 

estimated for bowheads migrating out of the Gulf of Anadyr during the northward spring migration 

(Mel’nikov et al., 2004). 

Wartzog et al. (1989) placed radio tags on bowheads and tracked the tagged whales in 1988. One tagged 

whale was tracked for 915 km as it migrated west at an average speed of 2.9 km/hour in ice-free waters. It 

traveled at an average speed of 3.7 km/hour in relatively ice-free waters and at an average speed of 2.7 

km/hour through eight-tenths ice cover and greater. Another whale traveled 1,291 km at an average speed 

of 5.13 km in ice-free waters but showed no directed migratory movement, staying within 81 km of the 

tagging site. Additional tagged whales in 1989 migrated 954-1,347 km at average speeds of 1.5-2.5 

km/hour (Wartzog et al., 1990). Mate, Krutzikowsky, and Winsor (2000) tagged 12 juvenile bowhead 

whales with satellite-monitored radio tags in the Canadian Beaufort Sea. The whale with the longest record 

traveled about 3,886 km from Canada across the Alaskan Beaufort Sea to the Chukchi Sea off Russia and 

averaged 5.0 km/hour. This whale’s speed was faster, though not significantly faster, in heavy ice than in 

open water. 

Oceanographic conditions can vary during the fall migration from open water to more than nine-tenths ice 

coverage. The extent of ice cover may influence the timing or duration of the fall migration. Miller, Elliot, 

and Richardson (1996) observed that whales within the Northstar region (147°-150° W. longitude) migrate 

closer to shore in light and moderate ice years and farther offshore in heavy ice years, with median 

distances offshore of 30-40 km (19-25 mi) in both light and moderate ice years and 60-70 km (37-43 mi) in 

heavy ice years. Moore (2000) looked at bowhead distribution and habitat selection in heavy, moderate, 

and light ice conditions in data collected during the autumn from 1982-1991. This study concluded that 

bowhead whales select shallow inner-shelf waters during moderate and light ice conditions and deeper 

slope habitat in heavy ice conditions. During the summer, bowheads selected continental slope waters and 

moderate ice conditions (Moore, DeMaster, and Dayton, 2000). Interseasonal depth and ice-cover habitats 

were significantly different for bowhead whales. Ljungblad et al. (1987) observed during the years from 

1979-1986 that the fall migration extended over a longer period, that higher whale densities were estimated, 

and that daily sighting rates were higher and peaked later in the season in light ice years as compared to 

heavy ice years. 

Fall aerial surveys of bowhead whales in the Alaskan Beaufort Sea have been conducted since 1979 by the 

Bureau of Land Management and the MMS (Ljungblad et al., 1987; Treacy, 1988-1998; Treacy, 2000). 

Over a 19-year period (1982-2000), there were 15 years with some level of offshore seismic exploration 

and/or drilling activity and four years (1994, 1995, 1999, and 2000) in which neither offshore activity took 

place during September or October. The parametric Tukey HSD test was applied to MMS fall aerialtransect data (1982-2000) to compare the distances of bowhead whales north of a normalized coastline in 

two analysis regions of the Alaskan Beaufort Sea from 140-156° W. longitude (see USDOI, MMS, 

2003a:Map 7). While the Tukey HSD indicates significant differences between individual years, it does 

not compare actual levels of human activity in those years nor does it test for potential effects of sea ice and 

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other oceanographic conditions on bowhead migrations (Treacy, 2000). Treacy (2000) showed in a yearto-year comparison that the mean migration regionwide in fall 1998 was significantly closer to shore in 

both the East and West Regions than in 1999, a year with no offshore seismic or drilling activity during the 

fall season in the Alaskan Beaufort Sea. 

While other factors may have dominating effects on site-specific distributions, such as prey concentrations, 

seismic activities, and localized vessel traffic, broad-area fall distributions of bowhead whale sightings in 

the central Alaskan Beaufort Sea may be driven by overall sea-ice severity (Treacy, 2001). Treacy (2002) 

concluded that: 

Bowhead whales occur farther offshore in heavy-ice years during fall migrations across the 

Central Alaskan Beaufort Sea (142° W to 155° W longitudes). Bowheads generally occupy 

nearshore waters in years of light sea-ice severity, somewhat more offshore waters in moderate ice 

years, and are even farther offshore in heavy ice years. While other factors...may have localized 

effects on site-specific distributions, broad-area distributions of bowhead whale sightings in the 

central Alaskan Beaufort Sea are related to overall sea-ice severity. 

Further evidence that bowhead whales migrate at varying distances from shore in different years also is 

provided by site-specific studies monitoring whale distribution relative to local seismic exploration in 

nearshore waters of the central Beaufort Sea (Miller et al., 1997; Miller, Elliot, and Richardson, 1998; 

Miller et al., 1999). In 1996, bowhead sightings were fairly broadly distributed between the 10-m and 50-

m depth contours. In 1997, bowhead sightings were fairly broadly distributed between the 10-m and 40-m 

depth contours, unusually close to shore. In 1998, the bowhead migration corridor generally was farther 

offshore than in either 1996 or 1997, between the 10-m and 100-m depth contours and approximately 10-60 

km from shore. 

Aerial surveys near the proposed Liberty development project in 1997 (BPXA, 1998) showed that the 

primary fall-migration route was offshore of the barrier islands, outside the proposed development area. A 

few bowheads were observed in lagoon entrances between the barrier islands and in the lagoons 

immediately inside the barrier islands, as shown in Figures 4-4 and 4-5 of the Environmental Report 

submitted by BPXA for the proposed Liberty development project (BPXA, 1998). Because survey 

coverage in the nearshore areas was more intensive than in offshore areas, maps and tabulations of raw 

sightings overestimate the importance of nearshore areas relative to offshore areas. Transects generally did 

not extend south of the middle of Stefansson Sound. Nevertheless, these data provide information on the 

presence of bowhead whales near the then-proposed Liberty development area during the fall migration. 

Probably only a small number of bowheads, if any, came within 10 km (6 mi) of the area. 

Some bowheads may swim inside the barrier islands during the fall migration. For example Frank Long, 

Jr. reported that whales are seen inside the barrier islands near Cross Island nearly every year and are 

sometimes seen between Seal Island and West Dock (U.S. Army Corps of Engineers, 1999). Crews from 

the commercial-whaling ships looked for the whales near the barrier islands in the Beaufort Sea and in the 

lagoons inside the barrier islands (Brower, 1980). Whales have been known to migrate south of Cross 

Island, Reindeer Island, and Argo Island during years when fall storms push ice against the barrier islands 

(Brower, 1980). Inupiat whaling crews from Nuiqsut also have noticed that the whale migration appears to 

be influenced by wind, with whales stopping when the winds are light and, when the wind starts blowing, 

the whales started moving through Captain Bay towards Cross Island (Tuckle, as cited in USDOI, MMS, 

1986a). Some bowhead whales have been observed swimming about 25 yards from the beach shoreline 

near Point Barrow during the fall migration (Rexford, as cited in USDOI, MMS, 1996a). A comment 

received from the Alaska Eskimo Whaling Commission on the Liberty draft EIS indicated that Inupiat 

workers at Endicott have, on occasion, sighted bowheads on the north side of Tern Island. No specific 

information was provided regarding the location of the whale. 

Data are limited on the bowhead fall migration through the Chukchi Sea before the whales move south into 

the Bering Sea. Bowhead whales commonly are seen from the coast to about 150 km (93 mi) offshore 

between Point Barrow and Icy Cape, suggesting that most bowheads disperse southwest after passing Point 

Barrow and cross the central Chukchi Sea near Herald Shoal to the northern coast of the Chukotka 

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Peninsula. However, sightings north of 72° N. latitude suggest that at least some whales migrate across the 

Chukchi Sea farther to the north. Mel’nikov, Zelensky, and Ainana (1997) argued that data suggest that 

after rounding Point Barrow, some bowheads head for the northwestern coast of the Chukotka Peninsula 

and others proceed primarily in the direction of the Bering Strait and into the Bering Sea. Mel’nikov (in 

USDOC, NOAA, and NSB, 2005) reported that abundance increases along northern Chukotka in 

September as whales come from the north. More whales are seen along the Chukotka coast in October. 

J.C. George (cited in IWC, 2004b) noted that bowheads pass through the Bering Strait into the Bering Sea 

between October and November on their way to overwintering areas in the Bering Sea. 

The timing, duration, and location of the fall migration along the Chukotka Peninsula are highly variable 

and are linked to the timing of freezeup (Mel’nikov, Zelensky, and Ainana, 1997). Whales migrate in “one 

short pulse over a month” in years with early freezeup, but when ice formation is late, whales migrate over 

a period of 1.5-2 months in 2 pulses (Mel’nikov, Zelensky, and Ainana, 1997:13). 

III.F.3.c(6)(e) Known Use of the Beaufort Sea by Bowheads. Bowhead whales may occur in the portions 

of the Beaufort Sea project area from spring through late fall. Spatial distribution, length of residency, 

habitat use, and timing of use is variable among years. Currently, the whales are first seen at Barrow 

around April 9-10, and this early pulse is dominated by juveniles. The size/age composition of whales 

entering the Beaufort gradually switches so that by later in May (May 15-June) large whales and cow/calf 

pairs are seen. Most of the herd is believed to have migrated past Barrow by late May. After passing 

Barrow, whales travel in spring leads through heavy pack ice, generally in a northeasterly direction, 

eventually heading east toward the southeastern Beaufort Sea, reaching the Canadian Beaufort by July. 

The number of bowheads observed feeding in Canadian waters is variable as is the distribution and 

behavior of whale observed there. They range through the Beaufort Sea in the summer. Large numbers of 

whale have been observed in early September in western portions of the planning area. It is not clear 

whether these whales migrated west early or did not migrate into the eastern Beaufort. The extent and 

locations of feeding in portions of the Beaufort Sea Planning Area varies considerably among years. In late 

summer (typically early September, but sometimes beginning earlier), bowhead whales migrate west. Data 

indicate that bowheads occupy inner and outer shelf habitat in light and moderate ice years but occur in 

outer shelf and slope habitat in years of heavy ice. 

III.F.3.c(6)(f) Known Use of the Chukchi Sea by Bowhead Whales. The Chukchi Sea Planning Area is an 

integral part of the total range of BCB Seas bowhead whales, and portions of this planning area are either 

part of or are primary calving ground during the spring for these whales. During the spring (widely 

bracketed as mid-March to approximately mid-June), bowheads migrate through leads on their way to 

summer feeding grounds. This lead system is an apparently obligate pathway for this population. Most 

calving apparently occurs during the spring migration between April and early June. In some years, parts 

of the spring lead system in the Chukchi Sea west, northwest, and southwest of Barrow are used as feeding 

areas over extended periods of time during the spring migration, but this use is inconsistent. Bowhead 

whales have been observed throughout the summer in waters along the northeastern Chukchi Peninsula of 

Russia (and along the southeastern portion of the Chukchi Peninsula in the Bering Sea). In the autumn, 

bowheads are in the Chukchi Sea as part of their autumn migration back to the Bering Sea from about midSeptember through October, passing through Bering Strait to the Bering Sea between October and 

November. Some of the bowheads whales are very far north (e.g., 72° N. latitude) in the Chukchi Sea. 

After passing Barrow, some of the whales head towards Wrangell Island and then follow the Asian coast 

southeast to the Bering Sea. Observations indicate bowheads feed along the Russian coast in the autumn. 

Lee et al. (2005) summarized that both bulk body tissue and baleen isotopic values indicate that the Bering 

and Chukchi seas are the predominant feeding areas for adults and subadults. Some of the feeding in the 

western Alaskan Beaufort Sea (e.g., west of Harrison Bay) is on prey advected from the Chukchi Sea. 

Recent systematic data about bowhead seasonal patterns of distribution, abundance, and habitat use in the 

Chukchi Sea Planning Area are lacking. The MMS funded large-scale surveys in this area when there was 

oil and gas leasing and exploration, but the last surveys were about 15 years ago. Since that period, data 

indicate that the bowhead population has increased substantially (about 3.3-3.4%/year), there have been 

significant reductions in sea-ice extent and a great decline in average sea-ice thickness ice. For these 

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reasons, we acknowledge considerable uncertainty about the extent of current use of the Chukchi Sea by 

bowhead whales, especially during the summer months and the fall migration. 

III.F.3.c(7) Feeding Behavior. The importance of the Alaskan Beaufort Sea as a feeding area for 

bowheads is an issue of concern to Inupiat whalers and is a major issue in evaluating the potential 

significance of any effect that may occur as a result of oil and gas activities in the Beaufort Sea and 

Chukchi Sea Planning Areas. Both MMS and the NSB believe that, with regards to understanding 

bowhead feeding within the Alaskan Beaufort Sea, there are major questions that remain to be answered 

(Stang and George, 2003). 

Because of the importance of this topic in past discussions and evaluations, we provide considerable detail 

about available information. 

Bowheads are filter feeders, filtering prey from the water through baleen fibers in their mouth. They 

apparently feed throughout the water column, including bottomfeeding as well as surface skim feeding 

(Würsig et al., 1989). Skim feeding can occur when animals are alone and conversely may occur in 

coordinated echelons of over a dozen animals (Würsig et al., 1989). Food items most commonly found in 

the stomachs of harvested bowheads include euphausiids, copepods, mysids, and amphipods. Euphausiids 

and copepods are thought to be their primary prey. Lowry, Sheffield, and George (2004) documented that 

other crustaceans and fish also were eaten but were minor components in samples consisting mostly of 

copepods or euphausiids. 

Available data indicate that bowhead whales feed in both the Chukchi and Beaufort Sea Planning Areas 

and that this use varies in degree among years, among individuals, and among areas. It is likely that 

bowheads continue to feed opportunistically where food is available as they move through or about the 

Alaskan Beaufort Sea, similar to what they are thought to do during the spring migration. 

Observations from the 1980’s documented that some feeding occurs in the spring in the northeastern 

Chukchi Sea, but this feeding was not consistently seen (e.g., Ljungblad et al., 1987; Carroll et al., 1987). 

Stomach contents from bowheads harvested between St. Lawrence Island and Point Barrow during April 

into June also indicated it is likely that some whales feed during the spring migration (Carroll et al., 1987; 

Shelden and Rugh, 1995, 2002). Carroll et al. (1987) reported that the region west of Point Barrow seems 

to be of particular importance for feeding, at least in some years, but whales may feed opportunistically at 

other locations in the lead system where oceanographic conditions produce locally abundant food. Lowry 

(1993) reported that the stomachs of 13 out of 36 spring-migrating bowheads harvested near Point Barrow 

between 1979 through 1988 contained food. Lowry estimated total volumes of contents in stomachs 

ranged from less than 1 to 60 liters (L), with an average of 12.2 L in eight specimens. Shelden and Rugh 

(1995) concluded that “In years when oceanographic conditions are favorable, the lead system near Barrow 

may serve as an important feeding ground in the spring (Carroll et al., 1997).” Richardson and Thomson 

(2002) concluded that some, probably limited, feeding occurs in the spring. 

It is known that bowhead whales feed in the Canadian Beaufort in the summer and early fall (e.g., Würsig 

et al, 1985), and in the Alaskan Beaufort in late summer/early fall (Lowry and Frost, 1984; Ljungblad et al., 

1986; Schell and Saupe, 1993; Lowry, Sheffield, and George, 2004; summarized in Richardson and 

Thomson, 2002). Available information indicates it is likely there is considerable inter-annual variability 

in the locations where feeding occurs during the summer and fall in the Alaska Beaufort Sea, in the length 

of time individuals spend feeding, and in the number of individuals feeding in various areas in the Beaufort 

Sea. 

In at least some years, some bowheads apparently take their time returning westward during the fall 

migration, sometimes barely moving at all, with some localities being used as staging areas due to abundant 

food resources or social reasons (Akootchook, 1995, as reported in NMFS, 2001). The Inupiat believe that 

whales follow the ocean currents carrying food organisms (e.g., Napageak, 1996, as reported in NMFS, 

2001). Bowheads have been observed feeding not more than 1,500 feet (ft) offshore in about 15-20 ft of 

water (Rexford, 1979, as reported in NMFS, 2001). Nuiqsut Mayor Nukapigak testified at the Nuiqsut 

Public Hearing on March 19, 2001, that he and others saw a hundred or so bowhead whales and gray 

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whales feeding near Northstar Island (USDOI, MMS, 2002). Some bowheads appear to feed east of Barter 

Island as they migrate westward (Thomson and Richardson, 1987). 

Interannual variability in the use of areas of the Beaufort Sea by bowheads for feeding has also been 

observed during aerial surveys by MMS and others. Ljungblad et al. (1986) reported that feeding 

bowheads comprised approximately 25% of the total bowheads observed during aerial surveys conducted 

in the Beaufort Sea from 1979 through 1985. Miller, Elliott, and Richardson (1998) reported observing 

many aggregations of feeding whales in nearshore waters near or just offshore of the 10-m depth contour 

during late summer/autumn 1997. In some years (e.g., 1997) (Miller, Elliot, and Richardson, 1998; Treacy, 

2002) many aggregations have been seen feeding (e.g., between Point Barrow and Smith Bay), whereas in 

other years very little feeding was observed. Bowheads occasionally have been observed feeding north of 

Flaxman Island. 

Treacy (2002) summarized data regarding the frequency of feeding and milling of bowhead whales 

observed on transect during aerial surveys conducted by MMS in the Beaufort Sea between 1982 and 2001. 

Because whales exhibiting milling behavior also may be feeding whales, whales with milling behavior 

were included with whales with apparent feeding behavior, even though some milling whales may have 

been engaged in other forms of social behavior. Feeding and milling whales observed per unit effort for 

each fall season (1982-2001) were mapped for visual comparison of relative occurrence of these behaviors 

in the Alaskan Beaufort Sea. Treacy (2002) summarized that a greater relative occurrence of feeding 

and/or milling behavior in bowhead whales was detected on transect near the mouth of Dease Inlet during 

aerial surveys of bowhead whales in the Beaufort Sea in 6 out of 20 years (1984, 1989, 1997, 1998, 1999, 

and 2000). In 4 of those years (1989, 1997, 1998, and 1999), Treacy also reported that a similar frequency 

of feeding and/or milling behavior was observed on transect near Cape Halkett, Alaska. During this 20-

year period, there were 9 years when feeding and/or milling behaviors were noted on transect, but not in or 

near either Dease Inlet or Cape Halkett (1982, 1983, 1985, 1986, 1988, 1990, 1993, 1995, and 1996). In 

1987, 1991, 1992, 1994, and 2001, Treacy (2002) reported that neither feeding nor milling behaviors were 

noted on transect at any location in the study area. Interannual and geographic variation in prey availability 

likely accounts for opportunistic feeding aggregations in particular years and locations (Treacy, 2002). 

Of 245 whales observed during 2003 during MMS Bowhead Whale Aerial Survey Program (BWASP), 

31% were classified as milling but none as feeding (Monnett and Treacy, 2005). Monnett and Treacy 

(2005) reported concentrations of milling whales nearshore north and northwest of Oliktok Pt. on 

September 20, 2003. In 2004, 29% of 253 bowheads observed were classified as feeding and 10% as 

milling. Locations of feeding whales included northeast of Barrow, in Smith Bay, and to the west of 

Kaktovik. Milling whales were in the far eastern portions of the study area. 

Data from MMS’ BWASP surveys (e.g., Treacy, 1998, 2000) shows high numbers of whales, many of 

which were feeding, in some areas over relatively long periods (e.g., weeks) of time in some years (e.g., 

1997) in areas in the western Alaskan Beaufort) but not in others. 

In the years that feeding whales are seen in a given area over a period of time, if the same individuals are 

staying in the areas and feeding, for these lengths of time, in those years they could be deriving a higher 

than typical percentage of their yearly energetic requirements from the Alaskan Beaufort Sea. 

Based on stomach content data supplemented by behavioral evidence, far more than 10% of the bowheads 

that passes through the eastern Alaskan Beaufort Sea during late summer and autumn feed there. Based on 

examination of the stomach contents of whales harvested in the autumn between 1969-2000, Lowry, 

Sheffield, and George (2004) found that there were no significant difference in the percentages of 

bowheads that had been feeding between those harvested near Kaktovik (83%), Barrow (75%), or between 

subadults (78%) versus adults (73%). Twenty-four out of 32 whales taken during the fall at Kaktovik from 

1979-2000 and included in this analysis were considered to have been feeding (Lowry and Sheffield, 2002). 

The status of three other whales was uncertain. Copepods were the dominant prey species by volume. 

Seventy-seven out of 106 whales harvested during the fall near Barrow from 1987-2000 and included in 

this analysis were considered to have been feeding. The status of two other whales was uncertain. There 

was no estimate of stomach contents for 61 whales. Of the 77 whales classified as feeding whales, there 

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were estimates of stomach volume for 16 autumn-feeding whales. Euphausiids were the dominant prey 

species by volume. 

Stomach volumes are reported for 34 of 90 whales harvested in the autumn at Kaktovik and Barrow. The 

stomach of the harvested whales contained highly variable amounts of food (range=2-150 L at Kaktovik, 

with 39% containing with >20 L and 11% containing >100 L; n=18) (range =1-189 L at Barrow, with 56% 

containing with >20 L and 31% containing >100 L; n=16) (Table 6 in Lowry, Sheffield, and George, 

2004:219). Four out of five whales taken during the fall at Cross Island from 1987-2000 were considered 

to have been feeding (at least 10 items or 1 L of prey). Length-girth relationships show that subadult 

bowheads, and possibly adults, gain weight while in the Beaufort Sea in summer and lose weight while 

elsewhere. Lipid content of blubber, at least in subadults, is higher when they leave the Beaufort in fall 

than when they return in spring. This evidence suggests the importance of feeding in the Beaufort Sea 

during summer and early autumn. They do not show what fraction of the annual feeding occurs in the 

eastern and central Beaufort Sea. Lowry et al. (2005:221) concluded that: 

...Bowhead whales feed regularly in the nearshore waters of the eastern, central and western 

Alaskan Beaufort Sea during September and October...this entire region should be considered an 

integral part of the summer-autumn feeding range of bowhead whales. Results of stomach 

contents analysis, aerial observations, and traditional knowledge suggest that reference to the 

passage of bowhead whales through this region as a ‘westward autumn migration’ is 

misleading...it is a very incomplete description of their activities in the region. Second, feeding 

near Barrow during the spring migration is not just occasional, but rather a relatively common 

event...However, the amount of food in the stomachs tends to be lower in spring than in 

autumn.... 

However, examination of stomach contents only showed whether or not bowhead whales had fed 

and what prey were eaten, and it does not directly address the relative significance of feeding in 

various regions...This unresolved issue remains important in the evaluation of possible cumulative 

effects of oil and gas development on bowhead whales..... 

Because the standard for classifying a whale as feeding is set so low, but prey volumes are rarely reported, 

we find it difficult to critically evaluate these findings relative to the issue of assessing the importance of 

various areas as bowhead feeding area, either to the population as a whole or to segments of the population. 

As pointed out by Thomson, Koski, and Richardson (2002), there is a large difference between a stomach 

with a small amount of prey (10 prey items) and one that is full. 

It is unclear how important this feeding is in terms of meeting the annual food needs of the population or to 

meeting the food needs of particular segments of the population (e.g., see discussion in Richardson and 

Thomson, 2002). Many assumptions, such as those about residence time, an approximations influence 

current conclusions. Because marked individuals have not been studied, it is unclear how much variability 

also exists among classes of individuals or individuals within a class in habitat residency times, or what 

factors influence residency times. 

Richardson and Thomson (2002) pointed out that bowhead activity throughout the year needs to be 

considered when evaluating the importance of feeding in the eastern Alaskan Beaufort Sea in late summer 

and autumn. 

Although numerous observations have been made of bowheads feeding during both the spring migration 

north to the Beaufort Sea and the fall migration west across the Alaskan Beaufort Sea, quantitative data 

showing how food consumed in the Alaskan Beaufort Sea contributes to the bowhead whale population’s 

overall annual energy needs is fairly limited. 

A study by Richardson (1987) concluded that food consumed in the eastern Beaufort Sea contributed little 

to the bowhead whale population’s annual energy needs, although the area may be important to some 

individual whales. The study area for this 1985-1986 study extended from eastern Camden Bay to the 

Alaska/Canada border from shore to the 200-m depth contour for the intensive study area, and beyond this 

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contour only for aerial survey data (Richardson and Thomson, 2002). The conclusion was controversial. 

The NSB’s Science Advisory Committee (1987) believed the study was too short in duration (two field 

seasons, one of which was limited by ice cover), suboptimal sampling designs, and difficulties in 

estimating food availability and consumption. The Committee did not accept the conclusion that the study 

area is unimportant as a feeding area for bowhead whales. 

Richardson and Thomson (2002) finalized the report from the MMS-funded feeding study entitled 

Bowhead Whale Feeding in the Eastern Alaskan Beaufort Sea: Update of Scientific and Traditional 

Information, which compiled and integrated existing traditional and scientific knowledge about the 

importance of the eastern Alaskan Beaufort Sea for feeding by bowhead whales. The project was an 

extension, with additional fieldwork (mainly in September of 1998, 1999, and 2000), of the previous study 

conducted in 1985 and 1985. The primary study area for this study extended the westward boundary about 

1° longitude from that of the 1985-1986 study. Thus the boundary for the latter study was near the middle 

of Camden Bay (145° W. longitude). With the concurrence of the NSB Scientific Review Board, efforts in 

deep offshore areas were de-emphasized in this latter study so as to concentrate efforts in shallow areas of 

particular concern to Kaktovik hunters and, potentially, to oil industry. Boat-based zooplankton sampling 

in 1998-2000 was limited to areas seaward of the 50-m contour. Aerial surveys extended to the 200-m 

contour, and MMS surveys extended further. 

Griffiths (1999) noted that the average zooplankton biomass in the study area was higher in 1986 than in 

1998. Habitat suitable for feeding appears to have been less common in the eastern Alaskan Beaufort Sea 

in 1998 than it was in 1986. In 1998, the principal feeding area within the eastern study area appeared to 

have been near Kaktovik. Griffiths, Thomson, and Bradstreet (2002) discussed zooplankton biomass 

samples collected in the Canadian Beaufort Sea during the 1980’s and in the Alaskan Beaufort Sea in 1986, 

1998, and 1999, where bowhead whales were either observed feeding or where whales had been observed 

feeding the previous day. Bowhead whales feed in areas with a higher than average concentration of 

zooplankton. The distribution of biomass values at locations with feeding bowheads indicates that the 

feeding threshold for bowheads may be a wet biomass of ~800 milligrams per cubic meter (mg/m3

). 

Most whales observed where zooplankton were sampled were subadults. “Adult bowheads tend to feed 

where large copepods predominate” (Richardson and Thomson, 2002:xxv). 

Koski (2000) summarized that the most common activity of bowheads in the eastern Alaskan Beaufort Sea 

during late summer and autumn was feeding. Bowhead use of the eastern Alaskan Beaufort Sea during late 

summer and autumn can be highly variable from year to year, with substantial differences in the numbers, 

size classes, residence times, and distributions of bowheads recorded there during 1985, 1986, 1998, and 

1999. 

Although various types of evidence (with the exception of isotope ratios) (see below) indicate that the 

eastern Beaufort Sea as a whole, including the Canadian Beaufort, is important to bowhead whales for 

feeding, the eastern Alaskan Beaufort Sea is only a small fraction of that area (Richardson and Thomson, 

2002. 

Similarly, data indicate that the amount of time bowheads spend feeding in the fall in the eastern Alaskan 

Beaufort Sea is highly variable among years. Available evidence indicates that in many years, the average 

bowhead does not spend much time in the eastern Alaskan Beaufort Sea and, thus, does not feed there 

extensively. Bowhead whales moved quickly through the area in 1998 and did not stop to feed for any 

great period of time. In contrast, during 1986, subadult whales stopped to feed in the study area for periods 

of at least several days. In 1999, adult whales stopped to feed in the Flaxman-to-Herschel zone for 

extended periods (Koski et al., 2002). In 1999, the main bowhead feeding areas were 20-60 km offshore in 

waters 40-100 m deep in the central part of the study area east and northeast of Kaktovik, between 

Kaktovik and Demarcation Bay (Koski, Miller, and Gazey, 2000). In 1999, one bowhead remained in the 

study area for at least 9 days, and 10 others remained for 1-6 days. Their mean rate of movement was 

about one-eighth of the rate observed in 1998. Of the individual bowheads that traveled thought this 

portion of the Alaskan Beaufort Sea, some spent at least seven days. 

 PEA-96 
Koski et al. (2002) used six calculation methods to estimate residence time for whales in the eastern 

Alaskan Beaufort Sea area, from Flaxman Island to Herschel Island. The annual residence time varied 

from 2.1-8.3 days and averaged 5.1 days. 

Miller et al. (2002) pointed out that it is difficult to recognize feeding behavior during typical aerial 

surveys. More focused observations are usually needed to obtain evidence of feeding below the surface. 

Baleen from bowhead whales provides a multiyear record of isotope ratios in prey species consumed during 

different seasons, including information about the occurrence of feeding in the Bering Sea and Chukchi Sea 

system. The isotopic composition of the whale is compared with the isotope ratios of its prey from various 

geographic locations to make estimates of the importance of the habitat as a feeding area. 

Carbon-isotope analysis of bowhead baleen has indicated that a significant amount of feeding may occur in 

wintering areas (Schell, Saupe, and Haubenstock, 1987). 

Carbon-isotope analysis of zooplankton, bowhead tissues, and bowhead baleen indicates that a significant 

amount of feeding may occur in areas west of the eastern Alaskan Beaufort Sea, at least by subadult whales 

(Schell, Saupe, and Haubenstock, 1987). Subadult whales show marked changes in the carbon isotope over 

the seasons, indicating that carbon in the body tissues is replaced to a large extent from feeding in summer 

and feeding in the autumn-winter months. In contrast, adult animals sampled show very little seasonal 

change in the carbon isotope and have an isotopic composition best matched by prey from the western and 

southern regions of their range, implying that little feeding occurs in summer (Schell and Saupe, 1983). 

The importance of the Alaskan Beaufort Sea as a bowhead feeding area also may have changed, or be 

changing, due to changes in prey availability elsewhere in their range. Isotope data indicate that primary 

productivity in the Bering and southern Chukchi seas is declining. Schell (1999a) looked at baleen from 35 

bowheads that were archived, in addition to whales from the recent harvest, and constructed an isotopic 

record that extends from 1947-1997. He inferred from this record that seasonal primary productivity in the 

North Pacific was higher over the period from 1947-1966, and then began a decline that continues to the 

most recent samples from 1997. Isotope ratios in 1997 are the lowest in 50 years and indicate a decline in 

the Bering Sea productivity of 35-40% from the carrying capacity that existed 30 years ago. If the decline 

in productivity continues, the relative importance of the eastern Beaufort Sea to feeding bowheads may 

increase (Schell, 1999b). 

Lee and Schell (2002) analyzed carbon isotope ratios in bowhead whale muscle, baleen, and fat, and in 

bowhead food organisms. They found that the isotopic signatures in zooplankton from Bering and Chukchi 

waters, which sometimes extend into the western Beaufort Sea, are similar and cannot be differentiated 

from one another. Zooplankton from the eastern Beaufort Sea (summer and early autumn range) has an 

isotopic signature that is distinct from that in Bering/Chukchi zooplankton. Lee and Schell compared these 

isotopic signatures in zooplankton to isotopic signatures in bowhead tissues. 

Lee and Schell (2002) found that carbon isotopes in the muscle sampled in the fall were not significantly 

different from those in muscle sampled in the spring. Carbon isotopes in the muscle during both seasons 

closely matched the isotope ratios of zooplankton from the Bering and Chukchi waters, indicating most of 

the annual food requirements of adults and subadults are met from that portion of their range. Based on the 

comparison of carbon isotopes in the zooplankton and in bowhead tissues, they estimate that 10-26% of the 

annual bowhead feeding activity was in the eastern and central Beaufort Sea waters, roughly east of 

Prudhoe Bay. 

Isotope data from baleen showed different feeding strategies by adult and subadult whales. Subadults 

acquired sufficient food in the eastern Beaufort Sea to alter the carbon isotope ratios in baleen relative to 

baleen representing feeding in Bering and Chukchi waters. Baleen plates from subadults showed a wider 

range in isotope ratios than those from adults, suggesting active feeding over all parts of their range. 

Much of the isotopic evidence seems to indicate that especially adult bowhead whales feed primarily on 

prey from the Bering and/or Chukchi Sea (Schell, Saupe, and Haubenstock, 1987; Schell and Saupe, 1993; 

 PEA-97 
Lee and Schell, 2002). Hoekstra et al. (2002) found seasonal values were consistent for all age classes of 

bowhead whales and suggested that the Bering and Beaufort seas are both important regions for feeding. 

In contrast, Hoekstra et al. (2002) concluded that seasonal fluctuations in carbon isotope values was 

consistent for all age classes of bowhead whales and suggests that the Bering and Beaufort seas are both 

important regions for feeding. Hoekstra et al. (2002) included data on isotope ratios in tissue subsamples 

from some of the same individual bowheads from Kaktovik and Barrow that were analyzed by Lee and 

Schell. There was an apparent discrepancy in the data from these two studies and somewhat different 

conclusions. The source of the discrepancy related to differences in the results from the Kaktovik whalemuscle samples. Hoekstra et al. (2002) suggest the percentage of annual feeding activity in the eastern 

Beaufort Sea could be on the order of 37-45% (compared to 10-26%). This discrepancy was considered 

critical in assessing the importance of feeding in the eastern Beaufort Sea. Lee and Schell subsequently 

repeated their isotopic analyses on additional subsamples from the same Kaktovik whales and obtained the 

same results they obtained initially (Lee and Schell, 2002). These re-analyses confirm the accuracy of the 

measurements reported by Lee and Schell in their draft report. Hoekstra et al. have not repeated their 

isotopic analyses at this time; therefore, the reason for the discrepancy between the two sets of data remains 

uncertain. 

Recently, Lee at al. (2005) published data from isotope ratio analyses of bowhead baleen from whales all of 

whom except one had been harvested in the autumn of 1997-1999 (Barrow: n=4; Kaktovik: n=10) and 

muscle (Barrow: n=14; Kaktovik: n=10). Results of these samples were compared to data from baleen 

collected in past studies from both spring (predominantly) and autumn whales in 1986-1988 (see Table 1 in 

Lee et al., 2005:274). Lee et al. (2005:285) concluded that the new data continue to indicate that the BCB 

Seas “bowhead whale population acquires the bulk of its annual food intake from the Bering-Chukchi 

system...Our data indicate that they acquire only a minority of their annual diet from the eastern and 

central Beaufort Sea...although subadult bowheads apparently feed there somewhat more often than do 

adults.” 

Thomson, Koski, and Richardson (2002) tried to reconcile the low estimates of summer feeding, as 

indicated by the isotope data of Lee and Schell, with other data: behavioral observations showing frequent 

feeding in the eastern Beaufort Sea during the summer and early autumn; zooplankton sampling near 

bowheads feeding in those areas shows that whales concentrate their feeding at locations with much higher 

than average biomasses of zooplankton; frequent occurrence of food in the stomachs of bowheads 

harvested in the Alaskan Beaufort Sea during late summer and autumn; and length-girth relationships show 

that subadult bowheads, and possibly adults, gain weight while in the Beaufort Sea in summer and lose 

weight while elsewhere; and lipid content of blubber, at least in subadults, is higher when they leave the 

Beaufort in fall than when they return in spring. Although some of this evidence suggests the importance 

of feeding in the Beaufort Sea during summer and early autumn, those types of data on summer and early 

fall feeding in the Beaufort Sea do not specifically show what fraction of the annual feeding occurs in the 

eastern and central Beaufort Sea. No comparable data on feeding, girth, or energy content have been 

obtained during and after the whales feed in the Chukchi sea in mid- to late fall. 

They concluded that bowheads fed for an average of 47% of their time in the eastern Alaskan Beaufort Sea 

during late summer and autumn. A substantial minority of the feeding occurred during travel. Among 

traveling whales, feeding as well as travel was occurring during a substantial percentage of the time, on the 

order of 43%. 

Assumptions about residence times influence these energetics-related estimates. As noted, available data 

indicate there is variability in habitat use among years. Because marked individuals have not been studied, 

it is unclear how much variability also exists among individuals in habitat residency times or what factors 

influence residency times. 

Estimated food consumption by bowheads in the eastern Alaskan study area (Flaxman Island to the 

Alaska/Canada border) was expressed as a percentage of total annual consumption by the population 

(Thomson, Koski, and Richardson, 2002). This was done separately for each year of the study and 

averaged for the 5 years of the study. 

 PEA-98 
The amount of feeding in the Chukchi Sea and Bering Strait in the fall is unknown as is the amount of 

feeding in the Bering Sea in the winter (Richardson and Thomson, 2002). Richardson and Thomson 

(2002:xxxviii) concluded that: “...behavioral, aerial-survey, and stomach-content data, as well as certain 

energetics data...show that bowheads also feed widely across the eastern and central Beaufort Sea in 

summer and fall.” 

They also concluded (Richardson and Thomson, 2002:xliii) that: 

In an average year, the population of bowhead whales derives an estimated 2.4% of annual 

energetic requirements” in the eastern part of the Alaskan Beaufort Sea studied. 

In 1 of 5 years of study, the population may have derived 7.5% or more of annual energetic 

requirements from the area. Utilization of the study area varies widely in time and space 

depending on zooplankton availability and other factors. In 4 of 5 study years, the bowhead 

population was estimated to consume <2% of its annual requirements within the eastern Alaskan 

Beaufort Sea during late summer and autumn.... 

Sensitivity analysis indicated that the upper bound of the 95% confidence interval was below 5% in four of 

the years. This upper bound was 16.5% in 1999, when the best estimate was 7.5%. Richardson and 

Thomson (2002) stated that they suspected the whale-days figure for 1999 was overestimated, and that the 

16.5% upper bound on that confidence interval was unrealistically high. Richardson and Thomson 

(2002:xliv) concluded that: “It is implausible that the population would consume more than a few percent 

of its annual food requirements in the study year in an average year.” 

One source of uncertainty that affected the analyses related to bowhead energetics is that the amount of 

feeding in the Chukchi Sea and Bering Strait in the fall is unknown as is the amount of feeding in the 

Bering Sea in the winter (Richardson and Thomson (2002). In mid to late fall, at least some bowheads feed 

in the southwest Chukchi. Detailed feeding studies have not been conducted in the Bering Sea in the 

winter. 

Thomson, Koski, and Richardson (2002) offered a feeding scenario, parts of which are speculative, that 

might be consistent with all these data. In this scenario, feeding occurs commonly in the Beaufort Sea in 

summer and early autumn, and bowheads gain energy stores while feeding there. However, zooplankton 

availability is not as high in the Beaufort Sea during summer as in the Chukchi and northern Bering seas 

during autumn. Also, feeding in the western Beaufort in autumn effectively may be on Chukchi prey 

advected to that area. Thus, bowheads might acquire more energy from Bering/Chukchi prey in autumn 

than from eastern and central Beaufort prey in summer/early autumn. Given this, plus an assumed low 

turnover rate of body components, the overall body composition of bowheads may be dominated by 

components from the Bering/Chukchi system, even at the end of the summer when leaving the Beaufort. 

Energy gained in the Beaufort and Chukchi seas during summer and fall presumably is used during winter 

when food availability is low, resulting in reduced girth and energy stores when returning to the Beaufort 

Sea in spring than when leaving in autumn. 

Richardson and Thomson (2002) pointed out that the isotopic and behavioral and stomach content data 

might not be in conflict, if prey availability in the Chukchi and/or Bering Sea were “notably better” than in 

the eastern Beaufort Sea. They also point out that: “...it is difficult to understand why bowheads would 

migrate from the Bering-Chukchi area to the Beaufort Sea if feeding in the Beaufort Sea were 

unimportant.” 

Richardson and Thomson (2002) note that while the study has provided many new data about bowhead 

feeding ecology and related biology, “...there are still numerous approximations, assumptions, data gaps, 

and variations of opinion regarding the interpretation of data. This is inevitable.... The authors do not 

claim that the project has resolved all uncertainty about the importance of the eastern Alaskan Beaufort Sea 

for feeding by bowhead whales....” 

 PEA-99 
Thus, the aforementioned study acknowledges certain limitations and the results of this study confirmed 

that the eastern Alaskan Beaufort Sea is used by bowhead whales for feeding (Stang and George, 2003). 

Richardson and Thomson (2002) summarized that this use varies widely in degree among years and 

individuals. 

III.F.3.c(8) Summary. Available new information does not indicate that there has been any significant 

negative or other change in the population status of the BCB Seas bowhead whale population since MMS 

consulted with NMFS in 2003 regarding Beaufort Lease Sale 195 (USDOI, MMS, 2004) or the Beaufort 

Sea multiple-sale EIS (USDOI, MMS, 2003a). All recent available information indicates that the 

population has continued to increase in abundance over the past decade and may have doubled in size since 

about 1978. The estimated current annual rate of increase is similar to the estimate for the 1978-1993 time 

series. There is discussion in the scientific and regulatory communities regarding the potential downlisting 

of this population. Bowheads feed in the Alaskan Beaufort Sea, but the extent and location of that feeding 

varies widely among years and locations. Bowheads are extremely long lived, slow growing, slow to 

mature, and currently have high survival rates. These features affect their vulnerability to pollution and 

disturbance in their environment. They are also unique in their ecology and their obligate use of lead 

systems to transit to summering grounds. This reliance on spring leads, and the fact that they apparently 

calve during the spring northward migration, also are features of their ecology that heightens their 

vulnerability to disturbance and oil spills in some areas. There are locations in the Beaufort Sea and the 

western Chukchi Sea where large numbers of bowheads have been observed feeding in many years. 

However, the significance of feeding in particular areas to the overall food requirements of the population 

or segments of the population is not clear. Available new information also does not indicate there has been 

any significant change in the distribution of this population during the autumn in the Beaufort Sea since 

NMFS wrote its Biological Opinion in 2001. Recent data on distribution, abundance, or habitat use in the 

Chukchi Sea Planning Area are not available, and there is little information about summer use in the 

Beaufort Sea. Since MMS and NMFS consulted on oil and gas leasing in the Chukchi Sea Planning Area, 

significant changes in the arctic environment have occurred and the population of bowheads has apparently 

greatly increased in abundance. We have taken available information into account in the update of our 

analyses of potential effects on this population. 

III.F.3.d. Fin Whale.

III.F.3.d(1) Introduction. Fin whales are large, fast-swimming baleen whales (Reeves, Silber, and Payne, 

1998). Adults range between 20 and 27 m (~65-89 ft) in length (Reeves, Silber, and Payne, 1998; Perry, 

DeMaster, and Silber, 1999a). They inhabit and feed in the Bering Sea throughout many months of the 

year and have been observed within the southwestern Chukchi Sea, along the northern coast of Chukotka. 

This area of the Chukchi was an important part of their historic range. The distribution and relative 

abundance of fin whales in these areas varies seasonally (see below). We include information about the fin 

whale in this Biological Evaluation to assess the potential for this species to be adversely affected by oiland gas-related activities in the Chukchi or Beaufort OCS Planning Areas. 

The MMS previously provided extensive information to NMFS about this species and its potential to be 

affected by oil and gas activities during our Section 7 consultation concerning potential oil and gas 

activities in Federal waters within lower Cook Inlet. For that consultation, MMS provided NMFS with our 

draft EIS for the Cook Inlet OCS Lease Sales 191 and 199 (USDOI, MMS, 2003b), which contained our 

biological evaluation of potential impacts to this species. Information provided herein expands, updates 

and, in some cases, summarizes information provided in that draft EIS. All available information is 

considered in our update of our analyses of the potential effects of the Proposed Action on fin whales. We 

provide an update of baseline information and information related to evaluating potential cumulative 

anthropogenic impacts on this population, as defined under the ESA. 

There is a revised draft stock assessment for 2005 available for this population (Angliss and Outlaw, 

2005:rev. 10/24/04). Details on fin whales that might lie outside the scope of the material provided here, or 

in our Cook Inlet multiple-sale EIS, may be provided in that document. We have reviewed and considered 

information in these documents and other available information in our evaluation of potential 

environmental impacts. 

 PEA-100 
III.F.3.d(2) ESA Status. Fin whales were listed as endangered under the ESA in 1973 (Perry, DeMaster, 

and Silber, 1999a) and as depleted under the MMPA. Under the 1994 amendments to the MMPA, they are 

categorized as a strategic stock. They are listed in Appendix I of CITES (Reeves, Silber, and Payne, 1998). 

Hunting of fin whales in the North Pacific was regulated under the 1946 International Convention for the 

Regulation of Whaling. The IWC began managing the commercial take of fin whales in the North Pacific 

in 1969 (Allen, 1980; Reeves et al., 1999) and prohibited their harvest in the North Pacific in 1976. In July 

1998, NMFS released a joint Draft Recovery Plan for the Fin Whale Balaenoptera physalus and Sei Whale 

Balaenoptera borealis (Reeves, Silber, and Payne, 1998). No critical habitat has been designated or 

proposed for fin whales in the North Pacific. 

III.F.3.d(3) Population Structure and Current Stock Definitions. The NMFS (Angliss and Lodge, 2002; 

Angliss and Outlaw, 2005:rev. 10/24/04) currently considers stock structure in fin whales to be equivocal. 

There is a lack of consistency among national and international regulatory entities in the number of stocks 

recognized. The NMFS (Angliss and Outlaw, 2005:rev.10/24/04) currently recognizes three population 

stocks of fin whales in U.S. Pacific waters: an Alaska or Northeast Pacific Stock, a 

California/Washington/Oregon Stock, and a Hawaii Stock. Investigators have reached different 

conclusions about the number and locations of population stocks in the North Pacific. However, tag 

recoveries (Rice, 1974) indicate that animals whose winter habitat includes the coast of southern California 

summer in locations from central California to the Gulf of Alaska; and individuals from the North 

American Pacific coast have been reported at locations as varied as central Baja California to the Bering 

Sea in the summer. Based on blood typing, morphology, and marking data, Fujino (1960) identified three 

“subpopulations” of fin whales in the North Pacific: the East China Sea, the eastern sides of the Aleutians, 

and the western sides of the Aleutians (Donovan, 1991). After examination of histological and tagging 

data, Mizroch, Rice, and Breiwick (1984) suggested five possible stocks. In 1971, the IWC divided North 

Pacific fin whales into two management units for the purposes of establishing catch limits: the East China 

Sea Stock and the rest of the North Pacific (Donovan, 1991). 

III.F.3.d(4) Past and Current Population Abundance. During visual cetacean surveys in July and August 

1999 in the central Bering Sea (CEBS), and in June and July 2000 in the southeastern Bering Sea, fin whale 

abundance estimates were almost five times higher in the central Bering Sea (provisional estimate of 3,368; 

CV = 0.29) (where most sightings were in a region of particularly high productivity along the shelf break) 

than in the southeastern Bering Sea (provisional estimate of 683; CV = 0.32) (Moore et al., 2002). During 

sighting cruises in July-August 2001-2003 of coastal waters (up to 85 km offshore) between the Kenai 

Peninsula (150° W. longitude) to Amchitka Pass (178° W. longitude), fin whales were observed from east 

of Kodiak Island to Samalga pass (Zerbini et al., In prep., as cited in Angliss and Outlaw, 2005:rev. 

10/24/04). These authors also estimated that 1,652 (95% CI = 1142-2389) fin whales occurred in this area. 

Based on these data, and those of Moore et al. (2002), NMFS provided an “initial estimate” of abundance 

of 5,703 fin whales west of the Kenai Peninsula. The NMFS considers this a minimum estimate of 

abundance for the stock, because no estimate is available east of the Kenai Peninsula (Angliss and Outlaw, 

2005:rev. 10/24/04). 

The NMFS has concluded that there is no reliable information about population-abundance trends, and that 

reliable estimates of current or historical abundance are not available, for the entire Northeast Pacific fin 

whale stock (Angliss and Lodge, 2002; Angliss and Outlaw, 2005:rev. 10/24/04). They provided a 

Potential Biological Removal for the Northeast Pacific Stock of 11.4. 

Estimates of population abundance in the North Pacific prior to commercial exploitation range from 42-

45,000 (Ohsumi and Wada, 1974). Angliss and Outlaw (2005:rev. 10/24/04, p. 197) cite a revised, 

unpublished February 2003 version of IWC Bureau of International Whaling Statistics data, stating that 

“Between 1925 and 1975, 47,645 fin whales were reported killed throughout the North Pacific.” 

III.F.3.d(5) Reproduction, Survival, and Non-Human-Related Sources of Mortality. Lockyer (1972) 

reported the age at sexual maturity in fin whales, for both sexes, to range from 5-15 years, while the 

average length is approximately 17.2 m (see references in Perry, DeMaster, and Silber, 1999a). Mating and 

calving are believed to occur on wintering grounds (Perry, DeMaster, and Silber, 1999a). A single calf is 

 PEA-101 
born after a gestation of about 12 months and weaned between 6 and 11 months of age (Best, 1966; 

Gambell, 1985). Calving intervals range between 2 and 3 years (Agler et al., 1993). About 35-40% of 

adult fin whale females give birth in any given year (Mizroch et al., In prep.). 

We discuss sources of human mortality and other impacts in the Baseline and Cumulative Effects sections. 

There is little information about natural causes of mortality (Perry, DeMaster, and Silber, 1999a). The 

NMFS summarized that “There are no known habitat issues that are of particular concern for this stock” 

(Angliss and Lodge, 2002, 2005). Perry, DeMaster, and Silber (1999a:51) listed the possible influences of 

disease or predation as “Unknown.” 

III.F.3.d(6) Migration, Distribution, and Habitat Use. Fin whales are widespread throughout temperate 

oceans of the world (Leatherwood et al., 1982; Perry, DeMaster, and Silber, 1999a; Reeves, Silber, and 

Payne, 1998). During the “summer” (defined by Mizroch et al., In prep. as April-October) fin whales 

inhabit temperate and subarctic waters throughout the North Pacific including the Gulf of Alaska, Bering 

Sea, and the southern Chukchi Sea (Mizroch, Rice, and Breiwick, 1984) (see details provided below for 

Gulf of Alaska, the Bering Sea, and Arctic) (see Figure 3). The summer southern range in the eastern 

North Pacific extends as far south to about 32° N., and rarely, even farther south off Mexico. During the 

historic whaling period, “summer” concentration areas included, but were not limited to, the Bering Seaeastern Aleutian Ground (60° N.-70° N. latitude, 175° E.-180° E. longitude, plus 45 °N.-65° N. latitude, 

180°-165° W. longitude) and the Gulf of Alaska Ground (also called the Northwest Coast Ground) (45° N.-

55° N. latitude, 165° W.-160° W. longitude, 45° N.-60° N. latitude, 160° W.-134° W. longitude), and the 

Vancouver Ground (40° N.-55° N. latitude, 134° W.-125° W. longitude) (Mizroch et al., In prep.). 

Mizroch et al.’s (In prep.) summary indicates that the fin whales range across the entire North Pacific from 

April to October, but in July and August concentrate in the Bering Sea-eastern Aleutian area. In September 

and October, sightings indicate that fin whales are in the Bering Sea, the Gulf of Alaska, and along the U.S. 

coast as far as Baja California (in October) (Mizroch et al., In prep.). 

Most fin whales are believed to migrate seasonally from relatively low latitude winter habitats where 

breeding and calving take place to relatively high latitude summer feeding habitats (Perry, DeMaster, and 

Silber, 1999a). The degree of mobility of local populations, and perhaps individuals, differs, presumably in 

response to patterns of distribution and abundance of their prey (Reeves et al., 1991; Mizroch et al., In 

prep.). Some populations migrate seasonally up to thousands of kilometers, whereas others are resident in 

areas with adequate prey (Reeves et al., 1999). Data from marked fin whales indicate that at least some 

individuals make long movements between wintering areas off Mexico and California to summer feeding 

areas in the Gulf of Alaska (Mizroch et al., In prep.). Angliss and Lodge (2005) reported that fin whales in 

the North Pacific generally are reported off the North American coast and Hawaii in winter and in the 

Bering Sea in summer. Passive acoustic data (McDonald and Fox, 1999) document that Hawaii is used in 

the winter by fin whales but indicate that densities are likely lower than those in California (Barlow, 1995; 

Forney, Barlow, and Carretta, 1995). 

Observations summarized by Mizroch et al. (In prep.) and reported elsewhere demonstrate that there are 

many fin whales in many locations in northerly waters as far north as 60° N. latitude in winter months. For 

example, in the 1960’s, 20 fin whales were sighted in the Gulf of Alaska in January (Berzin and Rovnin, 

1966). Fin whales have been observed near Kodiak Island and in Shelikof Strait in all seasons of the year 

(Mizroch et al, In prep.; Wynne and Witteveen, 2005). In January and February, fin whales have been 

sighted off Baja California, in the Aleutian area, and Bering Sea. Mizroch et al. (In prep.) point out that fin 

whales with small calves have not been seen during the winter months, and that it has not been 

demonstrated that individual whales are year-round residents in the northern areas. Thus, it is clear from 

their sighting summary that during many different times of the year, fin whales have been observed in 

widely scattered locations throughout their range in the North Pacific but areas where concentrations have 

been observed change seasonally. 

Reeves, Silber, and Payne (1998) reported that fin whales tend to feed in summer at high latitude and fast, 

or feed little at winter lower latitude habitats. During visual cetacean surveys in July and August 1999 in 

the central Bering Sea, “...aggregations of fin whales were often sighted in areas where the...echo 

sounder...identified large aggregations of zooplankton, euphausiids, or fish” (Angliss, DeMaster, and 

 PEA-102 
Lopez, 2001:160). Mizroch et al. (In prep.) concluded that catch densities and sightings show 

concentrations of fin whales within a highly productive “Bering Sea Green Belt” along the shelf edge 

(Springer, McRoy, and Flint, 1996). However, recent data on fin whale presence based on calls detected by 

bottom-mounted hydrophones document high levels of fin whale call rates along the U.S. Pacific coast 

from August to February (Moore et al., 1998; Watkins et al., 2000). The patterns of fin whale calls 

detected “...generally corresponded to seasonal productivity in the areas monitored...” (Moore et al., 

1998:623) and have been interpreted as a possible indication of the importance of this area for fin whale 

feeding during winter (Angliss and Lodge, 2002). 

The importance of specific feeding areas to populations or subpopulations of fin whales in the North 

Pacific is not understood. In the North Atlantic, 30-50 % of identified individual fin whales returned to 

specific feeding areas in subsequent years (Clapham and Seipt, 1991). The timing of arrival at feeding 

habitats can vary by sex and reproductive status, with pregnant females arriving earlier (Mackintosh, 1965). 

III.F.3.d(6)(a) Use of the Chukchi and Beaufort Seas. Available information suggests that the summer 

range of the fin whale extends as far as the Chukchi Sea (Rice, 1974) (see Angliss and Outlaw, 2005:rev. 

10/24/04, Fig. 40), including portions of the western Chukchi along the Chukotsk Peninsula and areas of 

the Alaskan Chukchi just north of the Bering Strait. Mizroch et al. (In prep.:14) reported “(T)hey regularly 

pass through the Bering Strait into the southwestern Chukchi Sea during August and September. They cite 

Zenkovich, a Russian biologist who wrote that in the 1930’s (quoted in Mizroch et al., In prep.) “...areas 

near Cape Dezhnev” are “...frequented by large schools (literally hundreds...) of fin whales....” and who 

also reported that fin whales were “encountered from early spring to the beginning of winter.” They report 

that Sleptsov (1961, cited in Mizroch et al., In prep.:14) wrote that fin whales occur “from the Bering Strait 

to the Arctic ice edge, in the coastal zone as well as the open sea. It...prefers areas free of ice, but also 

occurs in pools of open water among ice floes.” In more recent cruises (1979-1992) no fin whales were 

found in the Chukchi Sea or north of the Gulf of Anadyr (Vladimirov, 1994, as cited in Mizroch et al., In 

prep.). The southwestern Chukchi was probably a feeding area for fin whales. Information is not available 

to us that would permit evaluation of the current use of this area by fin whales. 

Mizroch et al. (In prep.) summarized that there have only been rare observations of fin whales into the 

eastern half of the Chukchi. Three (including a mother and calf) fin whales were observed together in the 

southern Chukchi at 67o 10.5’ N. latitude, 168o44.8’W. longitude directly north of the Bering Strait in July 

1981 (Ljungblad et al., 1982). No other sightings of fin whales were reported during aerial surveys of 

endangered whales in summer (July) and autumn (August, September and October) of 1979-1987 in the 

Northern Bering Sea (from north of St. Lawrence Island), the Chukchi Sea north of 66o N. latitude and east 

of the International Date Line, and the Alaskan Beaufort Sea from 157o 01’ W. longitude east to 140o W. 

longitude and offshore to 72o N. (Ljungblad et al., 1988). Mizroch et al. (In prep.:15) summarized that “No 

other sightings...of fin whales have ever been reported from the coast of Arctic Alaska....” They have not 

been observed during annual aerial surveys of the Beaufort Sea conducted in September and October from 

1982-2004 (e.g., Treacy, 2002; Moore, DeMaster, and Dayton, 2000). 

Thus, for the purposes of our analyses, we assume that: 

• Fin whales can occur within the Chukchi Sea, but would be rare in the Alaskan Chukchi except at 

the far southern regions near the Bering Strait. Within the Chukchi Sea, fin whales are more likely 

to occur near the Bering Strait, in the southwestern portion, along the coast of the Chukotka 

Peninsula, and are more likely in open water than in ice-covered waters. 

• Fin whales are not expected to occur in the northeastern Chukchi Sea, in the Chukchi Sea Planning 

Area, or in the Alaskan Beaufort Sea. 

• If climate changes in the Bering and Chukchi seas occur such that there is continued reduction in 

ice thickness or extent of coverage, increased periods of open water, more frequent climatic 

anomalies, such as El Niños and La Niñas, and /or changes in oceanographic currents or other 

processes, concentrations and distribution of fin whale prey species could occur, as could fin 

whale distribution and habitat use of these two seas. This possibility requires periodic 

consideration with regards for the potential of oil and gas activities within the Chukchi or, much 

less likely, the Beaufort Sea, to affect this species. 

 PEA-103 
III.F.3.d(6)(b) Use of the Bering Sea. Fin whales have been sighted in the Bering Sea during many 

different times of the year, including winter and early spring (e.g., January-March), summer (June-August) 

and in the autumn (September and October). Fin whales have been sighted the Bering Sea in JanuaryMarch. Sighting data indicate high use of the Bering Sea in June-August. As they concentrate in the 

Bering Sea-eastern Aleutian area, they may move along the continental shelf edge following the retreating 

ice. In September and October, sightings indicate there are still fin whales in the Bering Sea (Mizroch et 

al., In prep.). Observations summarized by Mizroch et al. demonstrate that there are many fin whales, 

although not with small calves, in northerly waters in winter months. 

During visual cetacean surveys in July and August 1999 in the central Bering Sea, and in June and July 

2000, fin whale abundance estimates were almost five times higher in the central-eastern Bering Sea 

(provisional estimate of 3,368, CV = 0.29) (where most sightings were in a region of particularly high 

productivity along the shelf break) than in the southeastern Bering Sea (provisional estimate of 683, CV = 

0.32) (Moore et al., 2002). One aggregation included more than 100 individuals. Aggregations of fin 

whales often coincided with areas where large aggregations of euphausiids, zooplankton, or fish were 

detected (Moore et al., 2000c). Mizroch et al. (In prep.) concluded that catch densities and sightings show 

concentrations of fin whales within a highly productive “Bering Sea Green Belt” along the shelf edge 

(Springer, McRoy, and Flint, 1996). During the NOAA Miller Freeman cruise in the Bering Sea from June 

5-July 6, 2004, fin whales were only observed in waters northwest of Nelson Lagoon (Waite, 2004). 

III.F.3.d(6)(c) Use of the Gulf of Alaska Region. Whaling records indicate that the fin whales were 

abundant in this area prior to exploitation. Nemoto and Kasuya (1965) reported that fin and sei whales 

were the primary species taken in the Gulf of Alaska during Japanese commercial whaling in recent 

catches. More than 150 fin whales were taken just south of the Kenai Peninsula. Other areas of high take 

in 1963 were especially southeast Alaska and areas offshore between Prince William Sound and Glacier 

Bay. Multiple smaller groups were taken offshore of areas south of Kodiak Island and the Alaska 

Peninsula to Unimak Pass, and large numbers were taken throughout the northern Gulf in an area bounded 

on the south at approximately 53° N. latitude. 

Available sighting data indicate that fin whales inhabit some areas of the Gulf of Alaska in every season 

and that the distribution and relative abundance of fin whales in this large area varies seasonally. For 

example, fin whales have been observed in all seasons in Shelikof Strait, bays on Kodiak Island (especially 

on the west side), and the Gulf of Alaska (Zweifelhofer, 2002, pers. commun.; Mizroch et al., In prep.; 

Wynne and Witteveen, 2005) but season usage varies (see Mizroch et al., In prep.; Wynne and Witteveen, 

2005; Baraff, Foy, and Wynne, 2005). In the 1960’s, 20 fin whales were sighted in the Gulf of Alaska in 

January (Berzin and Rovnin, 1966). Mizroch et al. concluded that fin whales likely are present in waters of 

Shelikof Strait, off the Kodiak Archipelago, and other northerly areas in winter because of the presence and 

distribution of their prey, including forage fish. In January and February, fin whales have been sighted in 

the Aleutian area. In April, sightings are reported all along the coast of the United States and Canada, but 

are concentrated around Kodiak Island. In May-July, sighting data indicate high use of the Gulf of Alaska, 

while August data show fewer sighting in the Gulf of Alaska. Mizroch et al. (In prep.) confirmed that fin 

whales from both sides of the Pacific concentrate in the Bering Sea-eastern Aleutian Island area in July and 

August and move along the continental shelf edge following the retreating ice. 

III.F.3.d(7) Foraging Ecology and Feeding Areas. Nemoto and Kasuya (1965) reported that fin whales 

feed in shallow coastal areas and marginal seas in addition to the open ocean. Citing the IWC (1992), 

Perry, DeMaster, and Silber (1999a) reported that there is great variation in the predominant prey of fin 

whales in different geographical areas, depending on which preys are locally abundant. While they 

“depend to a large extent on the small euphausiids” (see also Flinn et al., 2002) “and other zooplankton” 

(Perry, DeMaster, and Silber, 1999a:49), reported fish prey species in the Northern Hemisphere include 

capelin, Mallotus villosus; herring Clupea harengus; anchovies, Engraulis mordax; sand lance, Ammodytes 

spp) (Perry, DeMaster, and Silber, 1999a); and also octopus, squid, and ragfish (Flinn et al., 2002). 

Stomach-content data from whales killed during commercial whaling in the 1950’s and 1960’s, (Nemoto 

and Kasuya, 1965) indicated that in the Gulf of Alaska, Euphausia pacifica, Thysanoessa inermis, T. 

longipes, and T. spinifera are the primary prey of fin whales. Mizroch et al. (In prep.) summarized fish, 

 PEA-104 
especially capelin, Alaska pollock, and herring are the main prey north of 58° N. latitude in the Bering Sea. 

Reeves, Silber, and Payne (1998) reported the above species as primary prey in the North Pacific and also 

listed large copepods (mainly Calanus cristus), followed by herring, walleye pollock (Theragra 

chalcogramma), and capelin. Mizroch et al. (In prep.) summarize that fin whales appear to be able to make 

long-distance movements quickly to track prey aggregations and can switch their diet from krill to fish as 

they migrate northward. They aggregate where prey densities are high (Piatt and Methven, 1992; Piatt et 

al., 1989; Moore et al., 1998, 2002). Often these are areas with high phytoplankton production and along 

ocean fronts (Moore et al., 1998). Such areas often are, in turn, associated with the continental shelf and 

slope and other underwater geologic features such as seamounts and submarine canyons (Steele, 1974; 

Boehlert and Genin, 1987; Dower, Freeland, and Juniper, 1992; Moore et al., 1998). 

III.F.3.e. Humpback Whale (Central and Western North Pacific Stocks). 

III.F.3.e(1) Introduction. The humpback whale is a medium-sized baleen whale that inhabits a wide 

range of ocean habitats, including some documented use of the Chukchi Sea. Available information does 

not indicate that humpback whales typically occur, or have been documented to occur, within either the 

Chukchi or Beaufort Sea OCS Planning Area. We provide information about this species because of its 

potential occurrence in the southwestern Chukchi Sea. 

The MMS provides extensive information about humpback whales and the potential for humpbacks to be 

affected by oil and gas activities in the EIS for the Cook Inlet OCS Lease Sales 191 and 199. Herein, we 

provide much of the same basic information about humpbacked whales. We have focused our attention on 

the use of this species of areas where they potentially could be exposed to seismic survey activities that 

may occur within the Chukchi and Beaufort Sea Planning Areas. Additionally, we provide an update of 

baseline information and information related to evaluating potential cumulative anthropogenic impacts (as 

defined under the ESA) on humpback stocks that may be affected by oil and gas activities in these two 

areas. We refer readers to the recently revised draft stock assessments for these two stocks (Angliss and 

Outlaw, 2005:rev. 2/6/05 for western North Pacific stock; rev. 2/12/05 for central North Pacific stock) for 

additional detailed information beyond the scope of this biological evaluation. 

III.F.3.e(2) ESA Status. The IWC banned commercial hunting of humpbacks in the Pacific Ocean in 

1965 (Perry, DeMaster, and Silber, 1999b). Humpback whales were listed in 1973 as endangered under the 

ESA and as depleted under the MMPA. All stocks in U.S. waters are considered endangered (Perry, 

DeMaster, and Silber, 1999b, citing U.S. Dept. of Commerce, 1994b). All stocks of humpbacks are 

classified as “Protected Stocks” by the IWC. The NMFS published a Final Recovery Plan for the 

Humpback Whale in November 1991 (NMFS, 1991). 

On May 3, 2001, NMFS (66 FR 29502) published a final rule that established regulations applicable in 

waters within 200 nmi of Alaska that made it unlawful for a person subject to the jurisdiction of the U.S. to 

approach, by any means, within 100 yards (91.4 m) of a humpback whale. To prevent disturbance that 

could adversely affect humpbacks and to reduce threats from whale watching activities, NMFS also 

implemented a “slow, safe speed” requirement for vessels transiting near humpbacks. Exemptions to the 

rule were for commercial-fishing vessels during the course of fishing operations; for vessels with limited 

maneuverability; and for State, local, and Federal vessels operating in the course of official duty. 

III.F.3.e(3) Population Structure and Current Stock Definitions. There is “no clear consensus” 

(Calambokidis et al., 1997:6) about the population stock structure of humpback whales in the North Pacific 

due to insufficient information (Angliss and Lodge, 2002) (see further discussion in USDOI, MMS, 

2003a,b). For management purposes, the IWC lumps all humpback whales in the North Pacific Ocean into 

one stock (Donovan, 1991). 

Recently, NMFS (Angliss and Lodge, 2002; Angliss and Outlaw, 2005) concluded that, based on aerial, 

vessel, and photo-identification surveys, as well as genetic analyses, there are at least three populations 

within the U.S. Exclusive Economic Zone that move seasonally between winter/spring calving and mating 

areas and summer/fall feeding areas: 

 PEA-105 
1. a California/Oregon/Washington and Mexico stock; 

2. a Central North Pacific stock, which spends the winter/spring in the Hawaiian Islands and 

migrates seasonally to northern British Columbia, Southeast Alaska, Prince William Sound, and 

west to Unimak Pass; and 

3. a western North Pacific Stock, which spends the winter/spring in Japan and migrates to spend 

summer and fall to areas west of Unimak Pass (the Bering sea and Aleutian Islands) and possibly 

to the Gulf of Anadyr (NMML unpublished data, cited in Angliss and Lodge, 2004). 

Additionally, there is a winter/spring population of humpback whales in the Revillagigdeo Archipelago 

near Mexico’s offshore islands but the summer/fall destinations of these whales are not well-defined 

(Calambokidis et al., 1997). We are not aware of information that defines what population those 

humpbacks that enter the Chukchi Sea belong to. Based on the breakdown presented above, however, it is 

most likely that these whales would belong to the Western North Pacific stock. We assume that the 

California/Oregon/Washington stock would not be affected. We assume it is unlikely that whales from the 

Central North Pacific stock would be present in the northernmost Bering Sea near Bering Strait or 

seasonally be present within the southwestern Chukchi Sea. 

III.F.3.e(4) Past and Current Population Abundance in the North Pacific. The reliability of pre- and 

postexploration and of current abundance estimates is uncertain. Based on whaling records (Perry, 

DeMaster, and Silber, 1999b), Rice (1978b) estimated there were above 15,000 humpbacks in the North 

Pacific prior to commercial exploitation. It is known that Soviet whalers under-reported their takes of 

certain species of whales in the North Pacific (Yablokov, 1994). Johnson and Wolman (1984) and Rice 

(1978a) made reported rough estimates of 1,200 and 1,000, respectively, of the numbers of humpback 

surviving in the North Pacific after the cessation of commercial whaling for humpbacks in 1966. Perry, 

DeMaster, and Silber (1999b) caution that it is unclear whether these estimates are for the entire North 

Pacific or only the eastern North Pacific. With respect to the estimate of Johnson and Wolman and another 

postexploitation estimate of 1,400 by Gambell (1976), Calambokidis et al. (1997) concluded that “...the 

methods used for these estimates are uncertain and their reliability questionable.” 

Calambokidis et al. (1997) estimated the abundance of humpback whales in the mid-1990s in the wintering 

areas to be as follows: 394 (CV = 0.084) for the Western North Pacific Humpback whale stock; 4,005 (CV 

= 0.095) for the entire Central North Pacific stock on the wintering grounds in Hawaii; and about 1,600-

4,200 for Mexico. Based on aerial surveys of the Hawaiian Islands, Mobely et al. (2001) estimated 

abundance in 2000 to be 4,491 (95% CI = 3,146-5,836) with an estimated rate of increase of 7% for the 

period 1993-2000). Based on surveys in the eastern Bering Sea in 2000, Moore et al. (2002) provided an 

abundance estimate of 102 (95% CI = 40-262). In the central Bering Sea, 315 individual humpbacks have 

been identified in Prince William Sound between 1977-2001 (von Ziegesar et al., 2004, as cited in Angliss 

and Lodge, 2004). Waite et al. (1999) estimated that the annual abundance of humpbacks in the Kodiak 

area to be 651 (95% CI: 356-1,523). Based on mark-recapture estimates of humpbacks to the west of 

Kodiak, Witteveen, Wayne, and Quinn (2005) estimated 410 (95% CI = 241-683) humpbacks in this area. 

Straley, Quinn, and Gabriele (2002) estimated that the abundance of humpback whales in Southeast Alaska 

is 961. Angliss and Outlaw (2005) stated that: “There are no reliable estimates for the abundance of 

humpback whales at feeding areas for this stock” (the Western North Pacific Stock) “because surveys of 

the known feeding areas are incomplete, and because not all feeding areas are known.” 

Additional data regarding estimates for feeding areas in more southerly regions of Alaskan waters, British 

Columbia, and elsewhere are provided in Angliss and Outlaw (2005:183). 

There are not conclusive (Perry, DeMaster, and Silber, 1999b) or reliable (Angliss and Outlaw, 2005) data 

on current population trends for the western North Pacific stock. However, based on aerial surveys on the 

wintering grounds in Hawaii during 1993-2000, Mobely et al. (2001) estimated that the Central North 

Pacific stock is increasing by about 7%. 

Angliss and Outlaw (2005) provided a Potential Biological Removal (PBR) of 1.3 and 12.9 animals for the 

Western North Pacific Humpback Whales population and the entire Central North Pacific Stock, 

respectively. We note that the PBR for the Western North Pacific stock is based on the conservative 

 PEA-106 
minimum population estimate of 367 for this stock. Angliss and Outlaw (2005) provided a PBR of 9.9 for 

the northern portion of the Central North pacific stock and 3.0 animals for the Southeast Alaska portion. 

Based on the estimates for the three wintering areas, Calambokidis et al. (1997) reported that their best 

estimate for humpbacks in the North Pacific was 6,010 (SE ± 474). Adjusting for the effects of sex bias in 

their sampling and use of the higher estimate for Mexico yielded an estimate of about 8,000 humpback 

whales in the North Pacific. Perry, DeMaster, and Silber (1999b) concluded that the Calambokidis et al. 

(1997) estimate of about 6,000 probably was too low. 

III.F.3.e(5) Reproduction, Survival and Non-Human-Related Sources of Mortality. Humpbacks give 

birth and presumably mate on their wintering ground. Perry, DeMaster, and Silber (1999b) summarized 

that calving occurs along continental shelves in shallow coastal waters and off some oceanic islands (e.g., 

Hawaii). Calving in the Northern Hemisphere takes place between January and March (Johnson and 

Wolman, 1984). Information about age of sexual maturity is of uncertain reliability (Perry, DeMaster, and 

Silber, 1999b). While calving intervals very substantially, most female humpbacks typically calve at 1- to 

2-year intervals (Glockner-Ferrari and Ferrari, 1990; Straley, 1994). Gestation is about 12 months, and 

calves probably are weaned after about a year (Rice, 1967; Perry, DeMaster, and Silber, 1999b).

Causes of natural mortality in humpbacks in the North Pacific are relatively unknown, and rates have not 

been estimated. There are documented attacks by killer whales on humpbacks, but their known frequency 

is low (Whitehead, 1987; Perry, DeMaster, and Silber, 1999b). Lambertsen (1992) cited giant nematode 

infestation as a potential factor limiting humpback recovery. 

Based on sighting histories of individually identified female humpback in the North Pacific compiled 

between 1979 and 1995, Gabriele et al. (2001) calculated minimal and maximal estimates of humpback 

whale calf survival in the North Pacific of 0.150 (95% confidence intervals = 0.032, 0.378) and 0.241 (95% 

confidence intervals = 0.103, 0.434), respectively. 

Human sources of mortality, disturbance, and other effects on humpbacks, including commercial whaling 

are discussed in the cumulative effects section the Biological Evaluation. 

III.F.3.e(6) Migration, Distribution, and Habitat Use. 

III.F.3.e(6)(a) General Information. Humpback whales range throughout the world’s oceans, with lower 

frequency use of Arctic waters (Perry, DeMaster, and Silber, 1999b; Angliss and Lodge, 2002, 2005). 

Knowledge of their movements and the interrelations of individuals seen on different summer feeding 

grounds and those on different winter calving/breeding grounds is based on the recovery of whaling records 

about harvest locations, discovery marks used in commercial-whaling operations, photoidentification, 

genetic analyses, and comparison of songs (Perry, DeMaster, and Silber, 1999b). In the North Pacific each 

year, most (but not all individuals in all years) humpbacks undergo a seasonal migration from wintering 

habitats in tropical and temperate regions (10°-23° N. latitude), where they calve and mate, to more 

northern regions, where they feed on zooplankton and small schooling fish species in coastal and inland 

waters from Pt. Conception, California, to the Gulf of Alaska and then west along the Aleutian Islands, the 

Bering Sea, the Amchitka Peninsula and to the southeast into the Sea of Okhotsk (Angliss and Lodge, 

2002, 2005; Nemoto, 1957). During the period of commercial whaling, there are reports of this species in 

the southwestern Chukchi Sea (see information provided below in the section on use of the Arctic 

Subregion section). Feeding areas tend to be north of about 30° N. latitude, along the rim of the Pacific 

Ocean basin from California to Japan. In the most recent draft stock assessment for the western North 

Pacific stock, NMFS (as reported by Angliss and Outlaw, 2005) summarized that: “...new 

information...indicates that humpback whales from the western and Central North Pacific stocks mix on 

summer feeding grounds in the central Gulf of Alaska and perhaps the Bering Sea.” Individuals tend not to 

move between feeding areas. Mizroch et al. (2004) summarized that, based on all sightings, <2% of all 

individuals sighted were observed in more than one feeding area. 

III.F.3.e(6)(b) Use of the Beaufort and Chukchi Seas. The NMFS (1991b) (citing Nikulin, 1946 and 

Berzin and Rovin, both in Russian), summarized that the northern Bering Sea, Bering Strait, and southern 

 PEA-107 
Chukchi Sea along the Chukchi Peninsula are the northern extreme of the range of the humpback (see also 

Johnson and Wolman, 1984). However, neither Figure 38 of the most recent stock assessment for the 

Western North Pacific stock nor Figure 39 for the central North Pacific stock (Angliss and Outlaw-2005) 

depict the Chukchi Sa as part of the “approximate distribution” of humpback whales in the North Pacific. 

The draft assessment for the western North Pacific stock strikes reference to the Chukchi Sea. There are 

other references that indicate that both the historical and current summer feeding habitat of the humpback 

included, and at least sometimes includes, the southern portion, especially the southwestern portion, of the 

Chukchi Sea. Mizroch et al. (In prep.:14) cited Zenkovich, a Russian biologist who wrote that in the 

1930’s (quote in Mizroch et al., In prep.) “The Polar Sea, in areas near Cape Dezhnev...is frequented by 

large schools (literally hundreds...) of fin whales, humpbacks, and grays.” Mel’nikov (2000) wrote that: 

In the fall, humpback whales formed aggregations in the most southern part of the Chukchi Sea, in 

the Senyavin Strait, and in the northern part of the Gulf of Anadyr. The whales left the area of the 

survey prior to the start of ice formation. Both in the past and at present, these waters are the 

summer feeding ground of humpback whales. The regular character of the encounters with the 

humpback whales points to signs of the restoration in their numbers in the waters off Chukchi 

Peninsula. 

Available information does not indicate they inhabit northern portions of the Chukchi Sea or enter the 

Beaufort Sea. No sightings of fin whales were reported during aerial surveys of endangered whales in 

summer (July) and autumn (August, September, and October) of 1979-1987 in the Northern Bering Sea 

(from north of St. Lawrence Island), the Chukchi Sea north of 66o N. latitude and east of the International 

Date Line, and the Alaskan Beaufort Sea from 157o 01’ W. longitude east to 140o W. longitude and 

offshore to 72o N. latitude (Ljungblad et al., 1988). They have not been observed during annual aerial 

surveys of the Beaufort Sea conducted in September and October from 1982-2004 (e.g., Monnett and 

Treacy, 2005; Moore et al., 2000; Treacy, 2002). Recently, during a research cruise in which all marine 

mammals observed were recorded from July 5 to August 18, 2003, in the Chukchi and Beaufort seas, no 

humpback whales were observed (Bengtson and Cameron, 2003). 

Thus, for the purposes of our analyses, we assume that: 

• Humpback whales could occur in the southern Chukchi Sea, especially the southwestern Chukchi 

Sea. We assume this area is a portion of the summer feeding grounds for this species. 

• Humpback whales do not tend to occur further north and are not expected to occur within the 

Chukchi Sea project area. 

• Humpback whales do not occur in the Alaskan Beaufort Sea. 

As with the fin whale, continued climate change could result in changes in oceanographic conditions, the 

distribution of humpback prey species, and the distribution of humpback whales. This possibility requires 

periodic consideration with regards for the potential of oil and gas activities within the Chukchi or, much 

less likely, the Beaufort Sea, to affect this species. 

III.F.3.e(6)(c) Use of the Bering Sea and Gulf of Alaska Regions. In the summer, humpback whales 

regularly are present and feeding in areas near and within the Bering Sea and Gulf of Alaska.

Observations by Mel’nikov (2000) of humpback whales adjacent to the Chukotka Peninsula indicate that 

humpbacks whales are present and feeding in the most northerly portions of the northwestern Bering Sea in 

the summer and autumn prior to ice formation. 

In the summer, humpback whales regularly are present and feeding in areas near and within the Bering Sea. 

During ship surveys in the summers of 1999 and 2000, humpbacks were seen only in the central eastern 

Bering Sea southwest of St. Lawrence Islands and a few sightings occurred in the southeast Bering Sea, 

primarily north of eastern Aleutian Islands and outside of Bristol Bay (Moore et al., 2002). These sightings 

indicate that portions of the Bering Sea are important feeding areas for humpbacks (Moore et al., 2002). 

During ship surveys of 2,032 km in the eastern Bering Sea from June 5 to July 3, 2004, humpback whale 

sightings were scattered, with most seen nearshore from Akutan Island and west along the northern coast of 

the Alaska Peninsula (Waite, 2004:Fig. 3). Waite (2004) reported that the most northerly humpback 

sighting was about 300 km north of the Pribilof Islands. 

 PEA-108 
In the summer, humpback whales regularly are present and feeding in areas near and within the Gulf of 

Alaska and adjacent waters. Within the Gulf of Alaska region, evidence indicates that portions of the 

Kodiak Archipelago area, including the area off Albatross Banks (Waite et al., 1999; Witteveen, Wynne, 

and Quinn, 2005; Wynne and Witteveen, 2005); Prince William Sound; the Barren Islands (Sease and 

Fadely, 2001); and adjacent waters are important feeding areas for humpback whales. Acoustic monitoring 

from May 26-September 11, 2000, of the area south of Kodiak Island detected a large number of humpback 

whale calls (Waite, Wynne, and Mellinger, 2003). Based on aerial (1985) and vessel (1987) surveys, 

Brueggeman et al. (1989) suggested that there are discrete groups of humpbacks in the Shumagins, but data 

are insufficient to characterize numbers or structure of humpbacks in this area (Waite et al., 1999). During 

a 1994 ship survey in which a zig-zag pattern was followed extending about 200 nautical miles (nmi) (370 

km) southward between Tanaga Island in the Aleutians and the south end of the Kodiak Archipelago, 

Forney and Brownell (1996) observed humpback whales throughout the study area, especially in the 

eastern half, nearer to Kodiak Island and south of the Alaska Peninsula between 152° and 165° W. 

longitude. In this region, humpbacks were observed in “...scattered aggregations extending many miles” 

(Forney and Brownell (1996:4) usually offshore in deep water over the Aleutian Trench or Aleutian 

Abyssal Plain. Humpbacks also were observed scattered throughout the western region surveyed between 

167° and 175° W. longitude. Available information indicates that both the Central and Western North 

Pacific stocks overlap in their feeding areas in the Gulf of Alaska between the Shumagin Islands and 

Kodiak Island (Angliss and Outlaw, 2005). 

Portions of Southeast Alaska, including but not limited to Glacier Bay, Icy Strait, and Frederick Sound, are 

important feeding habitat for humpback whales with abundance peaking in late summer. Most, but not all, 

of these whales winter in Hawaii. While humpbacks are present in portions of Southeast Alaska yearround, few individuals are present year-round. 

III.F.3.e(7) Feeding Behavior. Humpbacks tend to feed on summer grounds and to not eat on winter 

grounds. Some low-latitude winter feeding has been observed and is considered opportunistic (Perry, 

DeMaster, and Silber, 1999b). They engulf large volumes of water and then filter small crustaceans and 

fish through baleen plates. They are relatively generalized in their feeding. In the Northern Hemisphere, 

known prey includes: euphausiids (krill); copepods; juvenile salmonids, Oncorhynchus spp.; Arctic cod, 

Boreogadus saida; walleye pollock, Theragra chalcogramma; pollock, Pollachius virens; pteropods; and 

cephalopods (Johnson and Wolman, 1984; Perry, DeMaster, and Silber, 1999b). Bottom feeding recently 

has been documented in humpbacks off the east coast of North America (Swingle, Barcho, and Pichford, 

1993). Within a feeding area, individuals may use a large part of the area. Two individual humpbacks 

sighted in the Kodiak area were observed to move 68 km (~42.25 mi) in 6 days and 10 km (~6.2 mi) in 1 

day, respectively (Waite et al., 1999). In the Kodiak Archipelago, winter aggregations of humpbacks were 

frequently observed at the head of several bays where capelin and herring spawn (Witteveen, Wynne, and 

Quinn, 2005), a pattern similar to that reported to Southeast Alaska where sites occupied in the winter are 

coincident with areas that have overwintering herring. 

III.F.3.f. Impact Assessment Overview. In the following section, we discuss potential effects of 2D/3D 

seismic surveys on bowhead whales, fin whales and humpback whales. We have taken the following 

approach to our effects analyses: 

1. We articulate the general ecological principles and assumptions underlying our analyses. 

2. We explicitly state specific assumptions about the action and the potentially affected species 

underlying the analyses. 

3. We determine those pathways by which endangered cetaceans could potentially be affected by 

different potential affecters associated with 2D/3D seismic surveys. We begin with background 

information necessary to understand the way(s) in which the general class of affecter (e.g., marine 

noise) could cause impacts to endangered whales. We proceed to review specific information 

about the type of affecter (e.g., seismic survey airgun noise, icebreakers, etc.) that could 

potentially cause impact. 

4. We evaluate whether any one of the three species has the potential to be exposed to affecters 

associated with pre and post-lease seismic survey activities in the Chukchi Sea and Beaufort Sea 

 PEA-109 
Planning Areas. If not, we give a brief summary of why we believe the species could not be 

affected. 

5. We then review specific information known about how the potentially exposed species may be 

impacted and evaluate potential impacts. 

6. We identify areas and times when potential effects might reasonably be expected to be greater 

than typical. 

7. We provide a summary of potential effects and our conclusions by species. 

Because MMS is taking a programmatic approach to understand potential effects of seismic surveys on 

these species, it is uncertain as to exactly where or how much seismic survey activity will occur. At 

present, MMS is providing best estimates about what levels and kinds of seismic survey activity may occur 

in 2006. If these estimates prove to be overestimates, we will be overestimating potential effects. If the 

estimates prove to be underestimates, then potential effects will have been underestimated. The mitigating 

measures outlined in Section IV and any additional measures implemented through the MMPA 

authorization process for the seismic surveys considered under the Proposed Action are intended to reduce 

such potential effects. 

III.F.3.f(1) Principles and Assumptions Underlying Analyses of Potential Effects. 

1. Potential effects on females with calves, on newborn calves, on all calves over their first year, and 

on females merit special consideration. Baleen whales are a relatively long-lived, late maturing group of 

species with relatively low reproductive rates, and with extremely high maternal investment in young. A 

major hypothesis of life history theory is that future survival and reproductive success are affected by early 

development conditions (e.g., Beauplet et al., 2005). The probability of postweaning survival to age 1 

increases with body condition in at least some marine mammals (e.g., Hall, McConnell, and Barker, 2001). 

In a species such as a bowhead whale, where the periods of body growth, maturation, gestation, maternal 

care, and intervals between reproductive attempts are all (mostly relatedly) long, the ability of the female to 

provide adequate care (e.g., through nursing and possibly the teaching of the locations of key resources) to 

her offspring during its period of dependency is critical to the continued recovery and the long-term 

viability of the population. In providing guidance on the evaluation of whether ocean noise disturbance of 

marine mammals should be considered biologically significant, the NRC (2005:82-83: Box 4-1) stated that: 

Different standards for disruption of breeding behavior should be considered for females and 

males. The ability of a female to select a mate, breed, gestate, and give birth to a viable offspring 

is so essential to populations that there should be very low tolerance of disturbances that might 

affect these activities.... 

Very low thresholds should be considered for any disturbance that might separate a dependent 

infant from its caregivers...Both the duration of nursing bouts and the distribution of intervals 

might be important.... 

The MMS acknowledges that the definite effects of anthropogenic noise on baleen (or other cetacean) 

calves, especially newborn calves, are uncertain. Absent direct information on potential effects on baleen 

calves, we draw on more general and somewhat analogous mammalian literature about potential effects on 

very young individuals. Data from other mammalian species, such as humans indicates that there are 

deleterious effects on offspring and juvenile hearing and health due to exposure to excessive noise during 

pregnancy, infancy (e.g, Committee on Environmental Health, 1997; Chang and Merzenich, 2003), and 

even childhood. “Developing mammals are more sensitive to noise...than adults” (Henley and Rybak, 

1995; Saunders and Chen, 2006). “Children and unborn children are in certain respects especially 

vulnerable to environmental effects...” (of noise). “It is not only the dose that is important in determining 

whether harm will arise but also the development stage when the exposure occurs. Organ systems that 

develop and mature over a long period are considered to be particularly vulnerable. Examples of such 

organ systems are the brain, the hormone system, the reproductive organs and the immune system” 

(Victorin, available at http://www.env.go.jp/en/topic/health03/01.pdf). 

 PEA-110 
Available data also indicate that female mammals with young (e.g., Bergerud, 1974), including female 

baleen whales (e.g., Tilt, 1985; Bauer, Mobley, and Herman, 1993; McCauley et al., 2000; NRC, 2003), 

show a heightened response to noise and disturbance, including seismic noise, than do juvenile and adult 

males. In summarizing the potential effects of noise on marine mammals, the NRC (2003:92) stated that: 

“Some age and sex classes are more sensitive to noise disturbance, and such disturbance may be more 

detrimental to young animals....” McCauley et al. (2000) summarized that in their experience, humpback 

whale cow/calf pairs are more likely to exhibit an avoidance response to a sound to which they are 

unaccustomed. They recommended that “...any management issues related to seismic surveys should 

consider the cow/calf responses as the defining limits” (McCauley et al., 2000:697). They also 

recommended that management decisions distinguish between whales that are in a “...key habitat type” 

(McCauley et al., 2000:698) and those that are migrating through an area. They list areas used for feeding, 

resting, socializing, mating, calving, or other key purposes as “key habitats.” 

When this information is considered in concert with data indicating potential extreme longevity of 

bowheads and the potential for repeated exposures throughout a whale’s life to seismic survey and other 

noise (see below and cumulative section), we believe that a cautious approach to development of additional 

mitigation and monitoring measures are unwarranted to further reduce the potential for adverse impacts to 

this segment of the bowhead whale population. 

2. Potential effects on “key habitat types” such as those used for calving, feeding, breeding, and 

resting, and those portions of the migratory pathway where the movements of the whales are 

constrained (e.g., the spring lead and polynya system in bowheads) merit special consideration. 

Whales do not use all portions of their range in a random fashion. Thus, impacts in all portions of the range 

are not of equal importance. To the extent that information exists, we have highlighted potential effects 

that could affect the use of areas used for calving, feeding, resting, and breeding by large numbers of 

whales. We also have highlighted potential effects on areas of the migratory pathway where the whale 

movements are constrained. 

3. The considerable potential longevity of the bowhead, coupled with its migratory use of the habitat, 

is important to consider in evaluating potential effects, and especially cumulative effects. An 

individual bowhead may experience multiple disturbance effects from the Proposed Actions at different 

locations within the same season, at the same general location but at different times during the same year, 

and/or over different and multiple years. Many bowheads already may have been exposed to multiple 

anthropogenic sources of loud noise (see cumulative section). 

4. Uncertainty should be acknowledged explicitly, because it may point to areas that may need 

further monitoring and consideration of adaptive management. The species of whales under 

consideration in this section are large endangered baleen whales. The whale species that is most likely to 

be exposed to the proposed activities is the stock(s) of bowhead whales that inhabit the Bering-ChukchiBeaufort Seas. This group of whales is important to the viability of the species as a whole and is a species 

of very high importance for subsistence and to the culture of Alaskan Native peoples of the northern Bering 

Sea, the Chukchi Sea, and the Beaufort Sea. It is important to acknowledge what we know and what we do 

not know. There are multiple sources of uncertainty in our analyses. These include, but are not limited to, 

uncertainty at the programmatic stage about the potential seismic surveys (where seismic surveys will 

occur; how many surveys will occur; how much noise will be produced by the firing of airguns; what the 

exact shape of related activities, such as support vessel type and activity will be); uncertainty about the 

potential effects of noise, especially repeated exposure to loud noise, on baleen whales; uncertainty about 

the current seasonal and temporal use of the Chukchi Sea evaluation area by bowhead and other whales, or 

to fully understand the importance of parts of the Beaufort Sea to bowhead whales. Thus, it is difficult to 

predict exposure in some parts of the area where the action could occur and to understand fully the 

potential effects of any exposure. While some sources of uncertainty cannot be reduced (e.g., the potential 

effects of long-term exposure to elevated noise levels), we can reduce overall uncertainty about potential 

impacts on baleen whales through requirements for monitoring coupled with an adaptive management 

approach whereby mitigations are tailored to conditions that are discovered through monitoring (Sec. 

III.F.3.g). 

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5. Where there is uncertainty on the status of the affected population relative to the species and 

other important characteristics of the population, the analyses should be conservative and cautious. 

The BCB Seas stock of bowhead whale is the only stock of bowheads that is robust and well on its way to 

recovery from depletion due to commercial whaling. Thus, the population that could be exposed to the 

Proposed Actions is important to the long-term viability of the species as a whole. This fact recommends a 

cautious approach to the analyses and the shaping of the action. 

6. The bowhead’s association with ice and its dependence on the spring lead and polynya system 

make it problematic to extrapolate about the potential impacts of seismic noise, or other loud noise, 

that could affect whales within these systems based on information available about other species that 

have been exposed to such potential affecters in open water, or even from information about bowheads 

that have been exposed to seismic-survey noise in open water. Unlike a species with less-constrained 

migratory pathways, bowhead whales are, over some of their migratory pathway, relatively fixed in at least 

part of the “road” they travel during spring migration. 

7. The fact that the BCB Seas stock of bowheads is hunted throughout most of its range needs to be 

considered in evaluating the potential effects that MMS actions could have on this species. Areas that 

exist in between areas where bowheads are hunted and times between periods when bowheads are hunted 

may have more significance to bowheads than they would if the species was not hunted. The fact that they 

are hunted also may heighten their response to anthropogenic acoustic disturbance, at least in some 

instances. 

8. Current status of the population is informative about potential response to the Proposed Actions. 

Based on available information, the bowhead population that may be affected is robust and resilient to a 

relatively steady lethal take in the subsistence hunt. This level of current mortality is below that which the 

IWC Scientific Committee believes is sustainable for this population. We do not expect any direct 

mortality on baleen whales from the Proposed Action but acknowledge that mortality could occur (e.g., 

through vessel strikes). However, it is clear that this population has continued to recover, despite previous 

activities that caused disturbance and lethal take. This continued recovery is informative about the 

population’s resilience at least to the level of disturbance and take that have occurred within the past 20 

years. 

Additional mitigation measures, which are outlined in Section IV, would further reduce the potential for 

adverse effects from MMS-permitted seismic surveys. We assume that monitoring and mitigation 

measures will be in place in both the Beaufort and Chukchi Sea Planning Areas similar to those mitigation 

measures that were required in the last two IHA’s dated August 13, 2001, and July 20, 1999, related to 

protection of bowhead whales and the availability of bowhead whales for taking by subsistence hunters 

during oil and gas activities in the Beaufort Sea (see the standard mitigation measures in Sec. II.A.3). We 

acknowledge that NMFS, through the process of this consultation or through the issuance of an IHA, could 

conclude that such measures do not afford sufficient protection to the whales or do not afford sufficient 

protection to the availability of bowhead whales for take by subsistence hunters, or NMFS could identify 

measures other than those specific measures in this PEA. The NMFS may require additional mitigation, 

monitoring, and reporting measures within any MMPA authorizations it grants for seismic survey permits 

considered under this PEA. In general, MMPA authorizations and their mitigation and monitoring 

measures are granted to ensure there are only a “negligible impact” on marine mammals and no 

“unmitigable adverse impact” to subsistence activities. (For definitions of these terms, see NMFS website 

at http://wwww.nmfs.noaa.gov/pr/glossary.htm). 

III.F.3.f(2) Potential Pathways of Impact from Seismic Surveys. During seismic surveys, endangered 

cetaceans potentially could be adversely affected by noise and disturbance both from the seismic sound 

sources; the seismic vessel; related support ships, boats, and icebreakers; and from aircraft supporting the 

ship or conducting required monitoring. Endangered cetaceans conceivably could be struck by ships or 

boats during seismic surveys. Small fuel spills could occur. Any or all of these factors potentially could 

adversely affect ESA-protected cetaceans in and/or near the Chukchi Sea or Beaufort Sea Planning Areas 

during OCS oil and gas exploration seismic survey activities. 

 PEA-112 
III.F.3.f(3) Potential Effects of Noise and Disturbance from Proposed Seismic Surveys. During OCS 

seismic surveys, noise can be transmitted through the air and through marine waters from a variety of 

sources including, but not limited to, the seismic-noise sources themselves that purposely release noise into 

the water, icebreakers, other ship and boat transit, high-resolution seismic surveys, and helicopter and 

fixed-winged aircraft traffic. One of the greatest concerns associated with the impacts of oil and gas 

exploration and development on marine mammals has to do with potential impacts of noise on their ability 

to function normally and on their health. Because of the importance of this issue, we provide two 

background sections. The first provides very general information relevant to understanding the fate of 

noise in the marine environment. The second provides general background about potential types of effects 

of noise on marine mammals. After these sections, we summarize the potential for each of the three 

species of whales to be exposed to seismic-survey-related noise and disturbance in the Chukchi and 

Beaufort Sea Program Area. We then review specific studies about the potential impacts on these species. 

III.F.3.f(4) Potential Effects of Noise and Disturbance from Proposed Actions on Bowhead, Fin, and 

Humpback Whales. One of the greatest concerns associated with the impacts of seismic surveying on 

marine mammals has to do with potential impacts of noise on their ability to function normally and on their 

health. During seismic surveying, noise is transmitted through the water and air from a variety of sources 

including, but not limited to, the acoustic sound source, support-vessel traffic, and helicopter and fixedwinged aircraft traffic. 

We provide background information on noise in the marine environment and on the marine acoustic 

environment in Section III.B. 

In this section, we provide background about potential effects of impacts of OCS oil- and gas-related noise 

and disturbance. This section should not be interpreted as indicating effects that are likely to occur due to 

the Proposed Actions on the bowhead whale, humpback or fin whale. Hearing (auditory) systems and 

perception are species specific and habitat dependent. As noted in the previous section and elsewhere in 

this evaluation, the fate of sound after it is produced is also site (especially in the Arctic), season, and 

weather specific. Because of these fundamental facts, the potential for a given sound to cause adverse 

effects to an animal also is species specific and habitat dependent. Because of differences in bathymetry 

and seabed characteristics of sites throughout the Chukchi Sea and Beaufort Sea Planning Areas, the 

distances that sounds of various frequencies, intensities, and pressures will propagate, and the resulting 

effects such sounds could have, also are expected to differ greatly among specific sites (e.g., among 

specific leasing blocks that differ in seabed properties, bathymetry, and the amount of wave action). Thus, 

the exact location of any sound source will determine the fate of sound released at that site and, therefore, 

will affect the possibility of impact on threatened and endangered species in or near the area. The time of 

year such sound is released will determine whether there is potential for individuals of a species to be 

exposed to that sound. 

Many marine mammals rely primarily on hearing for orientation and communication (e.g., Erbe and 

Farmer, 1998; NRC, 2003, 2005). The scientific community generally agrees that hearing is an important 

sense used by cetaceans (for example see Richardson et al., 1995a; NRC, 2003, 2005; National Resources 

Defense Council (NRDC), 1999, 2005; Marine Mammal Commission Sound Advisory Panel Minutes from 

meetings, MMC website). Marine mammals rely on sound to communicate, to find mates, to navigate, to 

orient (Erbe et al, 1999), to detect predators, and to gain other information about their environment. 

Because of their reliance on hearing, there is an increasing concern about the impacts of proliferation of 

anthropogenic noise on marine mammals, especially cetaceans. The NMFS (Carretta et al., 2001) 

summarized that a habitat concern for all whales, and especially for baleen whales, is the increasing level of 

human-caused noise in the world’s oceans. 

Increased noise levels could interfere with communication among whales, mask important natural sound, 

cause physiological damage, or alter normal behavior, such as causing avoidance behavior that keeps 

animals from an important area or displace a migration route farther from shore. Noise from various 

sources has been shown to affect many marine mammals (e.g., see Olesiuk et al., 1995; Richardson et al., 

1995a; Kraus et al., 1997; NRC, 2003; 2005) in ways ranging from subtle behavioral and physiological 

impacts to fatal. 

 PEA-113 
Several important documents that summarize information on this topic include: Richardson et al. (1995a); 

Hoffman (2002); Tasker et al. (1998); NRC (2003, 2005); NRDC (1999, 2005); IWC (2004a). Two 

particularly relevant summaries by the NRC have occurred within the last few years: Ocean Noise and 

Marine Mammals (NRC, 2003) and Marine Mammal Populations and Ocean Noise, Determining when 

Noise Causes Biologically Significant Effects (NRC, 2005). The IWC (2004) Scientific Committee 

Standing Working Group on Environmental Concerns held a mini-symposium on acoustics with a section 

of -the report dealing with seismic surveying. The Marine Mammal Commission (MMC) convened an 

Advisory Committee on Acoustic Impacts on Marine Mammals which is producing summaries of areas of 

agreement and disagreement concerning the impacts of noise on marine mammals as well as a summary 

from a subcommittee on mitigation and management of anthropogenic noise (summaries from caucuses 

available on their website). 

Results from several experimental studies have been published regarding sound-exposure metrics 

incorporating sound-pressure level and exposure duration. Recently, several investigators have examined 

noise-induced temporary threshold shift (TTS) in hearing in some odontocetes and pinnipeds exposed to 

moderate levels of underwater noise of various bandwidths and durations. Kastak et al. (2005:3154) 

summarized that: 

Because exposure to...noise in the marine environment is sporadic and interrupted, it is necessary 

to examine variables associated with varying noise sound pressure levels, intermittence of 

exposure, and total acoustic energy of exposure, in order to accurately predict the effects of noise 

on marine mammal hearing. 

While there is scientific acknowledgement of this statement, there are few instances where data are 

sufficient to evaluate the total energy exposure of a marine mammal from a given source. We acknowledge 

that evaluation of total energy could change our analyses. At present, we do not have the data necessary to 

make such a determination. The NMFS (2004) is preparing an EIS to evaluate the impacts of new acoustic 

criteria for evaluating take under the MMPA. 

Despite the increasing concern and attention noted above, there is still uncertainty about the potential 

impacts of sound on marine mammals, on the factors that determine response and effects, and especially on 

the long-term cumulative consequences of increasing noise in the world’s oceans from multiple sources 

(e.g., NRC, 2003, 2005). The NRC (2005) Committee on Characterizing Biologically Significant Marine 

Mammal Behavior concluded that it is unknown how or in what cases responses of marine mammals to 

anthropogenic sound rise to the levels of biologically significant effects. This group also developed an 

approach of injury and behavioral “take equivalents.” These take equivalents use a Severity Index that 

estimates the fraction of a take experienced by an individual animal. This severity index is higher if the 

activity could be causing harassment at a critical location or during a critical time (e.g., calving habitat). 

Because we have uncertainty about exactly where and how much activity will occur in 2006, we 

incorporate recommendations from the NRC (2005) qualitatively. 

Marine mammals use calls to communicate and probably listen to natural sounds to obtain information 

important for detecting open water, navigating, and avoiding predators. Increased noise levels could 

interfere with communication among whales, mask important natural sound, cause physiological damage, 

or alter normal behavior, such as causing avoidance behavior that keeps animals from an important area or 

displace a migration route farther from shore. Noise from various sources has been shown to affect many 

marine mammals (e.g., see Olesiuk et al., 1995; Richardson et al., 1995a; Kraus et al., 1997; NRC, 2003; 

2005) in ways ranging from subtle behavioral and physiological impacts to fatal. 

Available evidence indicates that reaction to sound, even within a species, may depend on the listener’s sex 

and reproductive status, possibly age and/or accumulated hearing damage, type of activity engaged in at the 

time or, in some cases, on group size (e.g., NRC, 2005; McCauley et al., 2000; Richardson et al., 1995a). 

For example, reaction to sound may vary depending on whether females have calves accompanying them, 

or whether individuals are feeding or migrating. It may depend on whether, how often, and in what 

context, the individual animal has heard the sound before. All of this specificity greatly complicates our 

ability in a given situation to predict the impacts of sound on a species or on classes of individuals within a 

 PEA-114 
species. Because of this, and following recommendations in McCauley et al. (2000), we attempt to take a 

cautious approach in our analyses and base conclusions about potential impacts on potential effects on the 

most sensitive members of a population. In addition, we make assumptions that sound will travel the 

maximums observed elsewhere, rather than minimums. 

While there is some general information available, evaluation of the impacts of noise on marine mammal 

species, particularly on cetaceans, is greatly hampered by uncertainty about their hearing capabilities and 

the range of sounds used by the whales for different functions (Richardson et al., 1995a; Gordon et al., 

1998; NRC, 2003, 2005). This is particularly true for baleen whales. Little is known about the actual 

hearing capabilities of the large whales or the impacts of sound on them, especially on them physically. 

While research in this area is increasing, it is likely that we will continue to have uncertainty about 

physiological effects on baleen whales because of the difficulties in studying them. Baleen whale hearing 

has not been studied directly. There are no specific data on sensitivity, frequency or intensity 

discrimination, or localization (Richardson et al., 1995a). Thus, predictions about potential impacts on 

baleen whales generally are based on assumptions about their hearing rather than actual studies of their 

hearing (Richardson et al., 1995a; Gordon et al., 1998; Ketten, 1998). Ketten (1998) summarized that the 

vocalizations of most animals are tightly linked to their peak hearing sensitivity. Hence, it is generally 

assumed that baleen whales hear in the same range as their typical vocalizations, even though there are no 

direct data from hearing tests on any baleen whale. Most baleen whale sounds are concentrated at 

frequencies less than 1 kilohertz (kHz), but the frequency range in bowhead songs can approach 4,000 

Hertz (Hz) (Richardson et al., 1995a). Most calls emitted by bowheads are in the frequency range of 50-

400 Hz, with a few extending to 1,200 Hz. Based on indirect evidence, at least some baleen whales are 

quite sensitive to frequencies below 1 kHz but can hear sounds up to a considerably higher but unknown 

frequency. Most of the manmade sounds that elicited reactions by baleen whales were at frequencies below 

1 kHz (Richardson et al., 1995a). Some or all baleen whales may hear infrasounds, sounds at frequencies 

well below those detectable by humans. Functional models indicate that the functional hearing of baleen 

whales may extend to 20 Hz. Even if the range of sensitive hearing does not extend below 20-50 Hz, 

whales may hear strong infrasounds at considerably lower frequencies. Based on work with other marine 

mammals, if hearing sensitivity is good at 50 Hz, strong infrasounds at 5 Hz might be detected (Richardson 

et al., 1995a). Bowhead whales, as well as blue and fin whales, are predicted to hear at frequencies as low 

as 10-15 Hertz. McDonald, Hildebrand, and Webb (1995) summarize that many baleen whales produce 

loud low-frequency sounds underwater a significant part of the time. Thus, species that are likely to be 

impacted by low-frequency sound include baleen whales such as bowheads. 

Most species also have the ability to hear beyond their peak range. This broader range of hearing probably 

is related to their need to detect other important environmental phenomena, such as the locations of 

predators or prey. Ketten (1998:2) summarized that, “The consensus of the data is that virtually all marine 

mammal species are potentially impacted by sound sources with a frequency of 500 Hertz or higher. This 

statement refers solely to the potential for marine mammal species to hear sounds of various frequencies. If 

a species cannot hear a sound, or hears it poorly, then the sound is unlikely to have a significant effect. 

Other factors, such as sound intensity, will determine whether the specific sound reaches the ears of any 

given marine mammal.” Considerable variation exists among marine mammals in hearing sensitivity and 

absolute hearing range (Richardson et al., 1995a; Ketten, 1998). Because of suspected differences in 

hearing sensitivity, it is likely that baleen whales and pinnipeds are more likely to be harmed by direct 

acoustic impact from low to mid-sonic range devices than odontocetes. Conversely, odontocetes are more 

likely to be harmed by high-frequency sounds. 

Little data are available about how most marine mammal species, especially large cetaceans, respond either 

behaviorally or physically to intense sound and to long-term increases in ambient noise levels, especially 

over the long term. Large cetaceans cannot be easily examined after exposure to a particular sound source. 

Whales often continue a certain activity (for example, feeding) even in the presence of airgun, drilling, or 

vessel sounds. Such continuation of activity does not confirm that the sound is not harmful to the cetacean. 

In many or all cases, this may be true: it may not be harmful (NRC, 2003). This type of interpretation is 

speculative. Whales, other marine mammals, and even humans, sometimes continue with important 

behaviors even in the presence of noise or other potentially harmful factors. Whales often fast for long 

lengths of time during the winter. The need to feed or to transit to feeding areas, for example, is possibly 

 PEA-115 
so great that they continue with the activity despite being harmed or bothered by the noise. For example, 

Native hunters reported to Huntington (2000) that beluga whales often ignore the approach of hunters when 

feeding, but at other times will attempt to avoid boats of hunters. 

III.F.3.f(4)(a) Potential Damage to Hearing. Ketten (1998) reported that hearing loss can be caused by 

exposure to sound that exceeds an ear’s tolerance (i.e., exhaustion or overextension of one or more ear 

components). Hearing loss to a marine mammal could result in an inability to communicate effectively 

with other members of its species, detect approaching predators or vessels, or echolocate (in the case of the 

toothed whales). 

Hearing loss resulting from exposure to sound often is referred to as a threshold shift. Some studies have 

shown that following exposure to a sufficiently intense sound, marine mammals may exhibit an increased 

hearing threshold, a threshold shift, after the sound has ceased (for example, Nachtigall et al., 2004; Kastak 

et al., 1999; Schlundt et al., 2000; Finneran et al., 2002). Thus, a threshold shift indicates that the sound 

exposure resulted in hearing loss causing decreased sensitivity. This type of hearing loss is called a 

temporary threshold shift if the individual recovers its pre-exposure sensitivity of hearing over time, or a 

permanent threshold shift if it does not. 

Ketten (1998) reported that whether or not a temporary threshold shift or a permanent threshold shift occurs 

will be determined primarily based on the extent of inner ear damage the received sound and the received 

sound level causes. In general, whether a given species will tend to be damaged by a given sound depends 

on the frequency sensitivity of the species. 

Long-lasting increases in hearing thresholds, which also can be described as long-lasting impairment of 

hearing ability, could impair the ability of the affected marine mammal to hear important communication 

signals or to interpret auditory signals (e.g., for orientation, prey finding, or predator detection), as well as 

impair the mammal’s ability to hear other important sounds such as sounds of predators, conspecifics (i.e., 

of the same species) or other whales (e.g., sounds of breaching), or approaching vessels. 

Most experiments have looked at the characteristics (e.g., intensity, frequency) of sounds at which 

temporary threshold shift and permanent threshold shift occurred. While research on this issue is 

occurring, it is still uncertain what the impacts may be of repeated exposure to such sounds and whether the 

marine mammals would avoid such sounds after exposure even if the exposure was causing temporary or 

permanent hearing damage if they were sufficiently motivated to remain in the area (e.g., because of a 

concentrated food resource). There are not data on which to determine the kinds or intensities of sound that 

could cause a TTS in a baleen whale. 

Permanent threshold shifts are less species dependent and more dependent on the length of time the peak 

pressure lasts and the signal rise time. Usually if exposure time is short, hearing sensitivity is recoverable. 

If exposure to the sound is long, or if the sound is broadband in higher frequencies and has intense sudden 

onset, loss might be permanent. Repeated long exposures to intense sound or sudden onset of intense 

sounds generally characterize sounds that cause permanent threshold shift in humans. Ketten (1998) stated 

that age-related hearing loss in humans is related to the accumulation of permanent-threshold-shift and 

temporary-threshold-shift damage to the ear. The NRC (2005:31) concluded that: “...there is evidence of 

age-related hearing loss” in marine mammals. 

Long-term impacts of OCS seismic survey noise on the hearing abilities of individual marine mammals are 

unknown. Information about the hearing capabilities of large baleen whales is mostly lacking, and data 

gathered on odontocetes and pinnipeds is minimal. As noted previously, the assumption is made that the 

area of greatest hearing sensitivity are at frequencies known to be used for intraspecific communication. 

Because real knowledge of sound sensitivity is lacking, we assume in our analyses that sensitivities shown 

by one species of baleen whale also could apply to another. This assumption errs on the side of caution, 

especially when using studies on a species such as the humpback, which uses a large sound repertoire in 

intraspecific communication, to infer possible impacts on other species such as the fin whale. Lacking 

more detailed knowledge of hearing capabilities of these large whales, a cautious analysis is prudent. 

III.F.3.f(4)(b) Potential Effects on Immune Function. Loud noise may also affect immune function. 

Romano et al. (2004:1125) summarized that “(A)nthropogenic sound is a potential “stressor” for marine 

mammals. Not only can loud or persistent noise impact the auditory system of cetaceans, it may impact 

 PEA-116 
health by bringing about changes in immune function, as has been shown in other mammals...” These 

authors (Romano et al., 2004:1131) identified neural immune measurements that may be “implicated as 

indicates of stress in the white whale and bottlenose dolphin that were either released acutely or changed 

over time during the experimental period.” Specifically, they found significant increases in aldosterone and 

a significant decrease in monocytes in a bottlenose dolphin after exposure to single impulsive sounds (up to 

200 kiloPascals [kPa]) from a seismic water gun. Neural-immune changes following exposure to single 

pure tones (up to 201 dB re 1 μPa) resembling sonar pings were minimal, but changes were observed over 

time. A beluga whale exposed to single underwater impulses produced by a seismic water gun had 

significantly higher norepinephrine, dopamine and epinephrine levels were significantly higher after highlevel sound exposure (>100 kPa) as compared with low-level exposures (<100 kPa) or controls and 

increased with increasing sound levels. Alkaline phosphatase decreased, but γ-glutamyltransferase 

increased over the experimental period. 

III.F.3.f(4)(c) Masking. When noise interferes with sounds used by the marine mammals (for example, 

interferes with their communication or echolocation), it is said to “mask” the sound (for example, a call to 

another whale might be masked by an icebreaker operating at a certain distance away). Noises can cause 

the masking of sounds that marine mammals need to hear to function (Erbe et al., 1999). That is, the 

presence of the masking noise can make it so that the animal cannot discern sounds of a given frequency 

and at a given level that it would be able to do in the absence of the masking noise. If sounds used by the 

marine mammals are masked to the point where they cannot provide the individual with needed 

information, critical natural behaviors could be disrupted and harm could result (Erbe and Farmer, 1998). 

In the presence of the masking sounds, the sounds the animal needs to hear must be of greater intensity for 

it to be able to detect and to discern the information in the sound. 

Erbe and Farmer (1998:1386) summarize that in “...the human and dolphin ear, low frequencies are more 

effective at masking high frequencies than vice versa; masking is maximum if the characteristic frequencies 

of the masker are similar to those of the signal...” They proposed that the factor most important for 

determining the masking effect of the noises was their temporal structure. The noise that was the most 

continuous with respect to frequency and time masked the beluga vocalization most effectively, whereas 

sounds (for example, natural icebreaking noise) that occurred in sharp pulses left quiet bands in between 

and left gaps through which the beluga could detect pieces of the call. In a given environment then, the 

impact of a noise on cetacean detection of signals likely would be influenced by both the frequency and the 

temporal characteristics of the noise, its signal-to-noise ratio, and by the same characteristics of other 

sounds occurring in the same vicinity (for example, a sound could be intermittent but contribute to masking 

if many intermittent noises were occurring). 

It is not known whether (or which) marine mammals can (Erbe and Farmer, 1998) and do adapt their 

vocalizations to background noise. Humans adapt the loudness of their speech according to several factors, 

including the loudness of the ambient noise (French and Steinberg, 1947). Dahlheim (1987) reported that 

in noisy environments, gray whales increase the timing and level of their vocalizations and use more 

frequency-modulated signals. 

III.F.3.f(4)(d) Behavioral Reactions. Available evidence also indicates that behavioral reaction to sound, 

even within a species, may depend on the listener’s sex and reproductive status, possibly age and/or 

accumulated hearing damage, type of activity engaged in at the time or, in some cases, on group size. For 

example, reaction to sound may vary depending on whether females have calves accompanying them, 

whether individuals are feeding or migrating (for example, see discussion of impacts of noise on humpback 

whales in McCauley et al., 2000 and Section IV.B.1.f(3)(d)2) of the Cook Inlet multiple-sale EIS) (USDOI, 

MMS, 2003b). Response may be influenced by whether, how often, and in what context, the individual 

animal has heard the sound before. All of this specificity greatly complicates our ability, in a given 

situation, to predict the behavioral response of a species, or on classes of individuals within a species, to a 

given sound. Because of this, and following recommendations in McCauley et al. (2000) (discussed 

above), we attempt to take a cautious approach in our analyses and base conclusions about potential 

impacts on potential effects on the most sensitive members of a population. In addition, we evaluate the 

potential for effects on bowheads making the implicit assumptions that sound may travel the maximums 

observed, rather than minimums and that whales engaged in a particular activity may respond at the 

maximum, not the minimum, distances observed in studies to date. These assumptions may overestimate 

 PEA-117 
potential effect in many cases. Because at least some of the airgun arrays being proposed for use in the 

Chukchi and Beaufort seas in 2006 have greater total output than many of those in previous studies, we also 

potentially may underestimate impact in some cases. 

III.F.3.f(5) Potential Exposure to Seismic-Survey Activities in the Proposed Action Area. Bowhead 

whales probably are the most likely of ESA-listed baleen whales to be impacted by OCS oil and gas-related 

seismic surveys in the Chukchi Sea or Beaufort Sea OCS areas because they commonly occur seasonally in 

areas where seismic surveying activity could occur. Bowhead whales have documented use of portions of 

both the Chukchi Sea and Beaufort Sea areas where seismic surveys could occur for: spring and fall 

migration; feeding; calving; resting; and limited breeding. Most of the calving for this population probably 

occurs between the Bering Strait and Point Barrow. Bowhead whales have a demonstrated sensitivity to 

some noise and disturbance, including noise and disturbance from seismic surveys. 

As summarized above, neither fin whales nor humpback whales are expected to appear at any time of the 

year within either the Chukchi Sea Planning Area or the Beaufort Sea Planning Area. Available evidence 

indicates these two species do not typically breed, calve, feed, rest, or migrate through such areas. They do 

seasonally appear in coastal waters of the southwestern Chukchi Sea, adjacent to the Chukchi Peninsula. 

Recent data to confirm their lack of use of areas of the Chukchi Sea evaluation area, except that portion of 

the evaluation area directly north of Barrow, are lacking. Based on available information, it is doubtful that 

they will be exposed to seismic survey noise at a noise level high enough to cause disturbance. 

III.F.3.f(5)(a) Noise and Disturbance from Seismic Surveys. Sound from seismic exploration is a potential 

source of noise disturbance to bowhead whales and other cetaceans in and near areas where the surveys 

may occur. Marine seismic operations use an acoustic sound source called an airgun to produce a burst of 

underwater sound from the release of compressed air, which forms a bubble that rapidly expands and then 

contracts. Typically, the rapid release of compressed air is used to produce an impulsive acoustic signal 

that is directed downward through the seabed. Seismic surveys using airguns, especially 2D and 3D 

seismic surveys, produce, at the source, underwater sound levels exceeding those of other activities 

discussed in this section. 

Animals sensitive to either low-frequency or high-frequency sounds may be affected. Seismic airguns are 

meant to produce low-frequency noise, generally below 200 Hz. However, the impulsive nature of the 

collapse of the air bubbles inevitably results in broadband sound characteristics. Goold (1996, cited in 

Stone, 2001) reported that high-frequency noise is also produced. Goold (1996a) also found significant 

levels of energy from airguns across the bandwidth up to 22 kHz. 

Airgun arrays are designed to focus the sound energy downward. Despite this, sound pulses also are 

projected horizontally, with the distance traveled depending on many factors, such as those discussed by 

Richardson et al. (1995a) and McCauley et al. (2000). McCauley et al. (2000) concluded that the most 

consistent measure of a received airgun signal was a measure of its energy, as was suggested by Richardson 

et al. (1995a) for pulsed sounds. Airgun arrays produce short-duration (transient) noise pulses with very 

high peak levels. The high peak level and impulsive nature of airguns have caused concern in the scientific 

and environmental communities. 

McCauley et al. (2000) stated that a precise definition of the seabed to at least 50-100 m is required to 

accurately predict horizontal propagation along a travel path. Based on experimental measurement of 

signals from a single airgun, McCauley et al. (2000) found signal differences of airgun broadband levels of 

up to 10 dB at a 1-km range. They concluded that such large differences in levels, measured for the same 

source at a given range within the same bay, demonstrated the importance of localized properties of the 

seabed in determining sound propagation. 

Received levels within a few kilometers typically exceed 160 dB re 1 μPa rms (Richardson et al., 1995a), 

depending on water depth, bottom type, ice cover, etc. In waters 25-50 m deep, sound produced by airguns 

can be detected 50-75 km away, and these detection ranges can exceed 100 km in deeper water (Richardson 

et al., 1995a). Sounds produced by seismic pulses can be detected by mysticetes and odontocetes that are 

from 10-100 km from the source (Greene and Richardson, 1988; Bowles et al., 1994; Richardson et al., 

1995a) or potentially farther under some conditions. Bowhead whales emit tonal-frequency modulated 

sounds at 50-400 Hz. A few calls have energy extending to 1,200 Hz. Bowheads also emit pulsive sounds 

 PEA-118 
in the frequency range of 25-3,500 Hz, as well as songs of about 20-500 Hz (Richardson et al., 1995a:Table 

7). 

Other factors that also can significantly affect sound propagation include the orientation of the receivers 

(the orientation of living animals could similarly affect reception), alignments and depths of array 

components and of functioning guns within the array, and airgun source depth. The depth at which the 

firing airgun is placed plays a crucial role in the potential for propagation. Increasing source depth 

consistently increased the received signal at any specified receiver depth (for example, the depth of the 

animal) and horizontal range. If the animal is in a shallow-water area and on the bottom, and the airgun is 

in much deeper water and downslope from the animal, attenuation will greatly affect the sound the animal 

will receive. 

Based on all of the aforementioned, McCauley et al. (2000) concluded that predicting sound propagation 

from any specified airgun array needs to be done on a case-by-case basis. 

Bain (2002) found that approximately one-third of sound levels measured during seismic surveys varied by 

6 dB from expected values. Shadow zones caused sound levels lower than expected, and land was an 

effective barrier to direct sound propagation. Cases of levels higher than expected probably were due to 

upslope enhancement of sound. Long-range propagation through the Strait of Juan de Fuca was better than 

expected, resulting in airgun noise being clearly audible at ranges of 60-70 km. This was the longest 

distance at which signal measurement was attempted, and it is possible that the sound was audible at even 

greater distances. Bain (2002) reports that high frequencies attenuated faster with distance (this would 

decrease impacts to beluga whales), and low frequencies were filtered out by propagation through shallow 

water. 

Tolstoy et al. (2004) compared measured versus modeled noise level radii associated with different seismic 

arrays in shallow and very deep water in the Gulf of Mexico and concluded that models may have been 

underestimating noise level radii in shallow water and overestimating those in very deep waters. 

Richardson et al. (1995a:290-291) summarized: “Underwater sound pulses from airgun arrays and similar 

sources are often audible many tens of kilometers away.” Transient noise from such a survey has been 

recorded on land seismometer arrays 6,100 km away after traveling the deep sound channel (Okal and 

Talandier, 1986). McDonald, Hildebrand, and Webb (1995) suggest that these same sounds may not have 

been detectable by a whale near the surface in the mid-Pacific because of entrapment in the deep sound 

channel. During monitoring using passive acoustics in the mid-Atlantic Ocean, Nieukirk et al. (2004) 

frequently recorded sounds from seismic airguns from locations more than 3,000 km from their array of 

autonomous hydrophones moored near the mid-Atlantic Ridge. Trends in the patterns of detection were 

similar in the 2 years of monitoring with airguns being detected every 10-20 seconds. Nieukirk et al. 

(2004:1838) reported that “Although airgun sounds tended to dominate recordings during the summer 

months, loud whale vocalizations could still be detected during intense airgun activity.... The high 

received level of these impulses on multiple hydrophones made it possible to estimate the location of the 

ships conducting the airgun surveys.” 

Regarding exposure of whales to seismic surveys, it is important to note that noise from a seismic survey is 

not stationary and is not a single event. The duration of exploration in a given area can continue for varied 

lengths of time, from days to months, with the area covered depending on the interests and needs of the 

explorer. The seismic survey activity, including airgun firing, vessel traffic and related activities may 

concentrate activity in a few hundred square kilometers for upward of a month (McCauley et al., 

2000:695). 

III.F.3.f(5)(b) Timing of Potential Exposure to Noise and Disturbance from Active Seismic Surveys. In the 

Proposed Action under consideration, we explicitly assume that 2D/3D seismic surveys could occur during 

the entire open water period in the Chukchi Sea and Beaufort Sea, except as restricted by mitigation 

measures. This includes a measure that requires that seismic operations will not occur in the Chukchi Sea 

spring lead system until July 1, unless authorized by NMFS, to provide bowhead mothers and calves 

additional protection. Further temporal/spatial/operational restrictions may be implemented for bowheads 

and/or other marine mammals through the MMPA authorization process for the seismic surveys considered 

under this PEA. 

 PEA-119 
Marine 2D/3D seismic surveys in the Beaufort Sea Planning Area likely would be feasible only in the 

months of August, September, and October. It is likely that the 2D/3D seismic surveys would be subject to 

conditions to eliminate or mitigate seismic-survey impacts during times of and in areas subject to 

subsistence harvests. Seismic surveys are likely to occur after the subsistence harvest is over or in areas 

where hunting does not occur. There is, however, uncertainty regarding bowhead use of the Alaskan 

Beaufort Sea during the summer months. Bowheads are typically observed in the Beaufort Sea until 

freezeup occurs. As required by both MMS under the permitting process and by NMFS under the MMPA 

authorization process, we assume that steps will be taken to avoid an unmitigable adverse effect on the 

availability of bowhead whales for take for subsistence, or that steps will be taken to avoid unreasonable 

conflict with such activities. Timing to avoid effects on subsistence takes may amplify disturbance on the 

whales, since it may concentrate seismic survey activity in between hunting activity, both spatially and 

temporally. 

In the Chukchi Sea, depending on ice conditions and conflict avoidance requirements, seismic surveys 

could not begin until July 1 (unless authorized by NMFS) and could occur into November. The total period 

of seismic surveys is likely to be considerably longer in the Chukchi Sea than in the Beaufort Sea. 

III.F.3.f(6) Potential Effects from Seismic Surveys. Because high-energy and impulsive sounds can cause 

hearing damage and behavioral reactions, there is considerable concern about the potential impacts of 

airguns on marine organisms. Sound from seismic surveys potentially could have negative impacts on 

marine mammals within or near the program areas. Because of the distance sound can travel through water 

(see the following), marine mammals in regions of the Beaufort Sea and Chukchi Sea that are near to the 

areas of survey, or that are connected to the area of exploration by a relatively unimpeded sound travel 

path, also could be affected by the sound. the Proposed Action alternatives considered under this PEA and 

the mitigation measures outlined in Sections II and IV are designed to avoid Level A takes (injury) of 

marine mammals and limit the potential for Level B takes (harassment). The mitigation measures and any 

imposed through the MMPA authorization process would further reduce the potential for causing possible 

adverse effects. Therefore, injuries directly from seismic survey noise are not expected to occur although 

there remains a limited potential for injury from strikes by seismic-survey-related vessels. 

The low-frequency noise (generally below 200 Hz) produced by seismic airguns are more likely to disturb 

baleen whales, which communicate at frequencies mostly below 3 kHz. Thus, their communications are 

more likely to overlap with those low frequencies than are the communications of beluga whales or small 

odontocetes in the areas of the survey. because high-frequency noise also IS produced, marine mammals 

that are sensitive to high frequencies also can be affected. 

The next few paragraphs provide a brief discussion of characteristics of the surveys relevant to whales and 

provide information from a number of studies on the effects of noise from seismic operations on bowhead 

whales, and where appropriate, other baleen whales. 

III.F.3.f(6)(a) Potential Effects of High-Resolution Site-Clearance Seismic Surveys on Endangered Whales. 

High-resolution site-clearance seismic-survey operations are described in detail in Section I.E.3. Because 

high-resolution seismic surveys are a lower energy and sound would be less likely to travel as far as sound 

from 2D/3D surveys, these activities are less likely to have significant effects on endangered whales. Our 

primary concern with respect to high-resolution surveys is the potential for these activities to add to noise 

and disturbance from 2D/3D seismic activities, and to cause local impacts within a specific area if large 

numbers of bowheads are present. We are specifically concerned about potential impacts that could occur 

if high-resolution seismic survey activity were inshore of 2D/3D seismic activities or drilling operations. A 

concentration of noise and disturbance-producing factors may keep bowhead whales from high value areas. 

The use of mitigation measures outlined in Sections II.A and IV.A is expected to reduce the potential for 

adverse effects from multiple seismic surveys in the biologically high-value areas. 

Bowheads appear to continue normal behavior at closer distances to high-resolution seismic surveys than to 

2D/3D seismic surveys. In the study by Richardson, Wells, and Würsig (1985), four controlled tests were 

conducted by firing a single 40 in3

 (0.66-L) airgun at a distance of 2-5 km (1.2-3.1 mi) from the whales. 

Bowheads sometimes continued normal activities (skim feeding, surfacing, diving, and travel) when the 

airgun began firing 3-5 km (1.86-3.1 mi) away (received noise levels at least 118-133 1 dB re 1 μPa rms. 

Some bowheads oriented away during an experiment at a range of 2-4.5 km (1.2-2.8 mi) and another 

 PEA-120 
experiment at a range of 0.2-1.2 km (0.12-0.75 mi) (received noise levels at least 124-131 and 124-134 dB, 

respectively). Frequencies of turns, predive flexes, and fluke-out dives were similar with and without 

airgun noise; and surfacing and respiration variables and call rates did not change significantly during the 

experiments. Because these activities are of shorter duration and have a smaller zone of influence, we 

believe it unlikely they would result in a significant effect on bowhead whales. 

III.F.3.f(6)(b) Potential Effects of 2D/3D Seismic Surveys on Endangered Whales. Marine 2D/3D seismic 

survey operations are described in detail in Section I.E.1and 2. 

Recent data are available regarding measured versus modeled noise level radii associated with different 

seismic arrays in shallow and very deep water (Tolstoy et al., 2004) that indicate some models may have 

been underestimating noise levels in shallow water. Because we explicitly assume that seismic surveys 

could occur anywhere within any portion of the Beaufort Sea or Chukchi Sea evaluation areas, as depicted 

in Map 1, and because the characteristics of the surveys themselves are likely to vary from those 

undertaken previously in either planning area, we assume that the propagation characteristics also might 

vary from those determined during previous seismic activities in these two planning areas. We summarize 

the information available about noise levels at distances determined or estimated during previous studies in 

these planning areas (primarily in the Beaufort Sea) and present and consider also the levels measured by 

Tolstoy et al. (2004). 

Numerous studies have been conducted on the effects of noise from seismic surveys on bowhead whales. 

The results from these studies have varied, in some cases considerably. Among some of these studies 

important variables were different. These included the type of seismic survey (2D versus 3D), the location 

of the study, and the year in which the study was conducted. Ice (and other weather-related factors) also 

varies among years as does the use of total available habitat by bowhead whales. Some of the studies 

employed different methodologies, some of which have been criticized by peer reviewers and others of 

which are more widely adopted. The studies involving the response of bowheads to 3D seismic surveys in 

which a large enough area was monitored both prior to, and following, initiation of the surveys to 

determine potential effects are most relevant to evaluating the potential effects of the Proposed Action. 

Because of the importance of the issue of potential noise disturbance of bowhead whales, we provide 

considerable detail on these studies below. We preface this section with an important point: In numerous 

reports regarding whale response to sound, it has been shown that multiple factors may be important in the 

whale’s response (e.g., McCauley et al., 2000). In some studies, these factors have been shown to include 

(but may not be limited to): the physical characteristics of the location into which the sound is released and 

the physical characteristics of the location where the whale is located at the time the sound is released; the 

whale’s sex and reproductive condition (e.g., groups with or without calves); the behavior of the whale 

(e.g., migrating or feeding); specific characteristics of the sound (e.g., frequency, duration, whether 

impulsive or not, etc.), and prior exposure to the sound. Thus, the fact that results from different studies of 

bowhead response to oil and gas-related sound have varied is not surprising. During the 1980’s, the 

behavior of bowhead whales exposed to noise pulses from seismic surveys was observed during the 

summer in the Canadian Beaufort Sea and during the fall migration across the Alaskan Beaufort Sea 

(Ljungblad et al., 1998; Richardson, Würsig, and Greene, 1986). In general, many of the seismic surveys 

conducted during the 1980’s were 2D seismic surveys that covered fairly large areas in a wide variety of 

areas. Additional studies on seismic surveys were conducted in the central Alaskan Beaufort Sea during 

the fall migration in 1996-1998. These surveys were 3D ocean bottom cable (OBC) seismic surveys that 

covered smaller areas in relatively nearshore area. 

Reeves, Ljungblad, and Clarke (1983) conducted aerial surveys to observe bowhead whale behavior in the 

presence of active seismic vessels. Whales were observed as close as 3 km (1.86 mi) and as far away as 

135 km (83.9 mi) from active seismic vessels. A pair of whales observed at a distance of 3 km (1.83 mi) 

were not moving while at the surface although the two whales’ heads were in contact. This pair of whales 

was closer to a shooting seismic vessel than any other whales observed during the study. No obvious 

response was apparent, but the observation time was brief. (The received level of low-frequency 

underwater sound from an underwater source, generally is lower by 1-7 dB near the surface (depth of 3 m) 

than at deeper (greater than 9 m) depths (Richardson et al., 1995a). It is possible these whales may have 

been at the surface to avoid the louder noise in deeper water. For the group of 20 whales at a distance of 

 PEA-121 
approximately 135 km (83.9 mi), the blow frequency per surfacing and time at the surface were greater 

during the period immediately after the seismic vessel began shooting than before it began shooting. The 

authors stated that no major changes in whale behavior (such as flight reactions) were observed that could 

unequivocally be interpreted as responses to seismic noise. They noted a possible exception of “huddling 

behavior,” which they thought may have been caused by the onset of seismic sounds. The authors 

concluded that although their results suggest some changes in behavior related to seismic sounds, the 

possibility that unquantified factors could be correlative dictates caution in attempting to establish causative 

explanations from the preliminary findings. 

Ljungblad et al. (1985) also reported findings from early tests of bowhead reactions to active seismic 

vessels in the Beaufort Sea. Methodological problems with this early study preclude us from drawing 

conclusions about potential bowhead reactions based on its findings. A subcommittee of the Scientific 

Committee of the IWC previously reviewed the data from this study and some members were critical of the 

methodology and analysis of the results. Comments included reference to: the small sample size; 

inconsistencies between the data and the conclusions; lack of documentation of calibration of sound 

monitoring; and possible interference from other active seismic vessels in the vicinity. The subcommittee 

acknowledged the difficulty of performing experiments of this kind, particularly in the absence of a control 

environment free of industrial noise. The subcommittee recommended that additional research taking into 

account the concerns expressed above be undertaken, and that the 1984 experimental results be subjected to 

rigorous reanalysis, before it could be used to draw any conclusions about the effects of seismic activity on 

this species (IWC, 1987). 

In their May 25, 2001, Biological Opinion for Federal Oil and Gas Leasing and Exploration by MMS 

within the Alaskan Beaufort Sea and its effects on the endangered bowhead whale, NMFS (2001:20) noted 

that early tests of bowhead reactions to active seismic vessels by Ljungblad et al. (1985): 

...were not conducted under controlled conditions (i.e., other noise sources were operating at the 

time), and approaches at greater ranges were not conducted, so results cannot be used to determine 

the range at which the whales first begin to respond to seismic activity. 

In Fraker et al. (1985), an active seismic vessel traveled toward a group of bowheads from a distance 

of 19 km (11.8 mi) to a distance of 13 km (8.18 mi). The whales did not appear to alter their general 

activities. Most whales surfaced and dove repeatedly and appeared to be feeding in the water column. 

During their repeated surfacing and dives, they moved slowly to the southeast (in the same direction as 

seismic-vessel travel) and then to the northwest (in the opposite direction of seismic-vessel travel). 

The study first stated that a weak avoidance reaction may have occurred but then stated there is no 

proof that the whales were avoiding the vessel. The net movement was about 3 km (1.86 mi). The 

study found no evidence of differences in behavior in the presence and absence of seismic noise, but 

noted that observations were limited. 

In another study (Richardson, Wells, and Wursig, 1985) involving a full-scale seismic vessel with a 47-L 

airgun array (estimated source level 245-252 dB re 1 μPa), bowheads began to orient away from the 

approaching ship when its airguns began to fire from 7.5 km (4.7 mi) away. This airgun array had about 30 

airguns, each with a volume of 80-125 in3

. The Mariner had been shooting seismic about 10 km to the west 

of a group of six whales. Prior to the start of the experimental seismic period, the whales were surfacing 

and diving and moving at slow to medium speed while at the surface. The vessel ceased shooting and 

moved within 7.5 km of the whales and began firing the airgun array while approaching the whales. The 

study reported no conspicuous change in behavior when the Mariner resumed shooting at 7.5 km (4.7 mi) 

away. The bowheads continued to surface and dive, moving at slow to medium speeds. The received level 

was estimated at 134-138 dB at 7 km (4.35 mi). Some near-bottom feeding (evidenced by mud being 

brought to the surface) continued until the vessel was 3 km (1.86 mi) away. The closest point of approach 

to any whale was approximately 1.5 km (0.93 mi), with the received level probably well over 160 dB. 

When the seismic vessel was within 1.5 km of whales at the original location, at least two of the whales 

were observed to have moved about 2 km to the south of the original location. The movements of the 

whales, at least while they were at the surface, were at the usual slow to moderate speeds. The study 

reported no conspicuous changes in behavior when the Mariner ceased shooting at 6 km beyond the 

whales. The bowheads were still surfacing and diving and moving at slow to medium speed. The most 

 PEA-122 
notable change in behavior apparently involved the cessation of feeding when the vessel was 3 km away. 

The whales began feeding again about 40 minutes after the seismic noise ceased. 

While conducting a monitoring program around a drilling operation, Koski and Johnson (1987) noted that 

the call rate of a single observed bowhead whale increased after a seismic operation had ceased. During the 

6.8 hours of observation, the whale was within 23-27 km (14.3-16.8 mi) from the drillship. A seismic 

vessel was reported to be from 120-135 km (74.58-83.9 mi) from the sonobuoy; the two loudest calls 

received were determined to be approximately 7 km (4.35 mi) and 9 km (5.6 mi) from the sonobuoy, with 

received levels of 119 and 118 dB, respectively. Approximate signal-to-noise ratios were 24 and 22 dB, 

respectively. No information is provided regarding the exact distance the whale was from the operating 

seismic vessel. The increase in call rate was noted within 25 minutes after seismic noise ceased. It also 

needs to be noted that there were few, if any, calls heard during the 2 hours prior to the start of seismic 

operations, so it is unclear whether the increase in call rate relates to cessation of seismic noise, the 

presence of the operating drillship, the combination of both activities, or some other factor that occurred in 

the late afternoon. During this same study a subgroup of four to seven whales within a larger group (15-20 

whales) was noted moving rapidly away from an approaching seismic vessel at a distance of 22-24 km 

(13.7-14.9 mi). The received level of seismic pulses was 137 dB at 19 km (11.8 mi) from the sonobuoy 

and 22 km from the whales. The surfacing and diving were unusually brief, and there were unusually few 

blows per surfacing. No information was available regarding the time required for these whales to return to 

normal behavior. 

Based on early data, Richardson and Malme (1993) concluded that collectively, scientific studies showed 

that most bowheads usually show strong avoidance response when an operating seismic vessel approaches 

within 6-8 km (3.8-5.0 mi). Based on those early data, they believed that strong avoidance occurred when 

received levels of seismic noise are 150-180 dB re 1 μPa (Richardson and Malme, 1993). Bowheads also 

may show specific behavioral changes, such as reduced surfacing; reduced dive durations; changes in 

respiration rates, including fewer blows per surfacing, and longer intervals between successive blows; and 

they may temporarily change their individual swimming paths. The authors noted that surfacing, 

respiration, and dive cycles may be altered in the same manner as those of whales closer to the vessels. 

Bowhead surface-respiration-dive characteristics appeared to recover to pre-exposure levels within 30-60 

minutes following the cessation of the seismic activity. Strong pulses of seismic noise were often 

detectable 25-50 km (15.5-31 mi) from seismic vessels, but in early studies, bowheads exposed to seismic 

sounds from vessels more than about 7.5 km (4.7 mi) away rarely showed avoidance. As noted above, 

seismic pulses can be detectable 100 km (62.2 mi) or more away and in some habitats, have been detected 

at distances from the source more than ten times that distance. Bowheads also may show specific 

behavioral changes, such as reduced surfacing; reduced dive durations; changes in respiration rates, 

including fewer blows per surfacing, and longer intervals between successive blows; and they may 

temporarily change their individual swimming paths. The authors noted that surfacing, respiration, and 

dive cycles may be altered in the same manner as those of whales closer to the vessels. 

The North Slope Borough (NSB) believes that many of the early studies were different from the real-world 

situation, and various and important limitations of these studies have been pointed out. Most studies did 

not involve actively migrating whales; and those whales were being approached by the seismic ships 

whereas in the real world, the fall migrating whales are actively moving to the west and they are 

approaching a distant seismic boat that is firing. The MMS notes that many studies were observational and 

involved opportunistic sightings of whales in the vicinity of seismic operations. The studies were not 

designed to show whether more subtle reactions are occurring that can displace the migration corridor, so 

no definitive conclusions can be drawn from them on whether or not the overall fall migration is displaced 

by seismic activity. 

Inupiat whalers suggested that the fall bowhead migration tended to be farther offshore when there was 

abundant seismic work off northern Alaska. Aerial surveys have been conducted since 1979 to determine 

the distribution and abundance of bowhead whales in the Beaufort Sea during their fall migration. These 

surveys have been used for comparing the axis of the bowhead whale migration between years. Survey 

data from 1982-1987 were examined to determine whether industrial activity was resulting in displacement 

of bowhead whales farther offshore (Ljungblad et al., 1988). It was determined that a good indicator of 

annual shifts in bowhead distribution could be obtained by analyzing the distance of random bowhead 

sightings from shore (Zeh, as cited in Ljungblad et al., 1988). An analysis of the distance of random 

 PEA-123 
bowhead sightings from shore (a total of 60 bowhead sightings) was conducted, but no significant 

differences were detected in the bowhead migratory route between years. The axis of the bowhead 

migratory route near Barrow was found to fall between 18 and 30 km (7.76 and 18.6 mi) from shore. 

Although the analysis involved a relatively small sample size, these observations provide some insight into 

migration patterns during these years. The NSB, in a letter dated July 25, 1997, questioned the sample size 

and the precision of the Ljungblad et al. (1988) report to determine whether or not a displacement of fall 

migrating whales had occurred and how big a displacement would have to be before it could be detected. 

Using larger sample sizes (for which confidence intervals were calculated) obtained over a larger study 

area, the aerial survey project found many between-year (1982-1996) differences in the median water depth 

at whale sightings that were highly significant (P less than 0.05) (Treacy, 1997). Median depths ranged 

between 18 m (59 ft) in 1989 and 347 m (1,138 ft) in 1983, with an overall cumulative depth of 37 m (121 

ft, confidence interval = 37-38 m). The aerial survey project has reported a potential association between 

water depth of the bowhead migration and general ice severity, especially in 1983, when severe ice cover 

may have forced the axis of the migration into waters 347 m (1,138 ft) deep. To address short-term 

bowhead whale displacement within a given year from site-specific industrial noise, MMS and NMFS 

require industry to conduct site-specific monitoring programs when industrial activity occurs in the 

Beaufort Sea Planning Area during fall bowhead migrations. 

Since 1996, many of the open-water seismic surveys in State of Alaska waters and adjacent nearshore 

Federal waters of the central Alaskan Beaufort Sea were OCB surveys. These surveys were 3D seismic 

programs. The area to be surveyed is divided into patches, each patch being approximately 5.9 by 4.0 km 

in size. Within each patch, several receiving cables are laid parallel to each other on the seafloor. Seismic 

data are acquired by towing the airguns along a series of source lines oriented perpendicular to the 

receiving cables. While seismic-data acquisition is ongoing on one patch, vessels are deploying cable on 

the next patch to be surveyed and/or retrieving cables from a patch where seismic surveys have been 

completed. Airgun arrays have varied in size each year from 1996-1998 with the smallest, a 560-in3

 array 

with 8 airguns, and the largest, a 1,500-in3

 array with 16 airguns. A marine mammal and acoustical 

monitoring program was conducted in conjunction with the seismic program each year in accordance with 

provisions of the NMFS Incidental Harassment Authorization. 

Based on 1996-1998 data, there was little or no evidence that bowhead headings, general activities, or 

swimming speeds were affected by seismic exploration. Bowheads approaching from the northeast and 

east showed similar headings at times with and without seismic operations. Miller et al. (1999) stated that 

the lack of any statistically significant differences in headings should be interpreted cautiously. Changes in 

headings must have occurred given the avoidance by most bowheads of the area within 20 or even 30 km of 

active seismic operations. Miller et al. (1999) noted that the distance at which deflection began cannot be 

determined precisely, but they stated that considering times with operations on offshore patches, deflection 

may have begun about 35 km to the east. Some bowheads approached within 19-21 km of the airguns 

when they were operating on the offshore patches. It appears that in 1998, the offshore deflection might 

have persisted for at least 40-50 km west of the area of seismic operations. In contrast, during 1996-1997, 

there were several sightings in areas 25-40 km west of the most recent shotpoint, indicating the deflection 

in 1996-1997 may not have persisted as far to the west. 

LGL Ltd.; Environmental Research Assocs., Inc.; and Greeneridge Sciences Inc. conducted a marine 

mammal monitoring program for a seismic survey near the Northstar Development Project in 1996 (Miller 

et al., 1997). The marine mammal monitoring program was continued for subsequent seismic surveys in 

nearshore waters of the Beaufort Sea in 1997 and 1998 (Miller, Elliot, and Richardson, 1998; Miller et al., 

1999). Details of these studies are provided in the Beaufort Sea multiple-sale final EIS (USDOI, MMS, 

2003a). 

These studies indicated that the bowhead whale-migration corridor in the central Alaskan Beaufort Sea 

during 1998 was similar to the corridor in many prior years, although not 1997. In 1997, nearly all 

bowheads sighted were in relatively nearshore waters. The results of the 1996-1998 studies indicated a 

tendency for the general bowhead whale-migration corridor to be farther offshore on days with seismic 

airguns operating compared to days without seismic airguns operating, although the distances of bowheads 

from shore during airgun operations overlapped with those in the absence of airgun operations. Aerial 

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survey results indicated that bowheads tended to avoid the area around the operating source, perhaps to a 

radius of about 20-30 km. 

Sighting rates within a radius of 20 km of seismic operations were significantly lower during seismic 

operations than when no seismic operations were happening. Within 12-24 hours after seismic operations 

ended, the sighting rate within 20 km was similar to the sighting rate beyond 20 km. There was little or no 

evidence of differences in headings, general activities, and swimming speeds of bowheads with and without 

seismic operations. Overall, the 1996-1998 results show that most bowheads avoided the area within about 

20-30 km of the operating airguns. Within 12-24 hours after seismic operations ended, the sighting rate 

within 20 km was similar to the sighting rate beyond 20 km. 

The observed 20-30 km area of avoidance is a larger avoidance radius than documented by previous 

scientific studies in the 1980’s and smaller than the 30 mi suggested by subsistence whalers, based on their 

experience with the types of seismic operations that occurred in the Beaufort Sea before 1996 (Richardson, 

2000). The seismic-survey activities in the 1980’s were 2D, whereas the recent seismic activities were 3D 

OBC. 

Based on recordings of bowhead whale calls made during these same studies, Greene et al. (1999), 

summarized that results for the 3 years of study indicated that: (1) bowhead whales call frequently during 

the autumn migration through the study area; (2) calling continued at times when whales were exposed to 

airgun pulses; and (3) call-detection rates at some locations differed significantly when airguns were 

detectable versus not detectable. However, there was no significant tendency for the call-detection rate to 

change in a consistent way at times when airguns started or stopped. 

During the 1996-1998 bowhead hunting seasons, seismic operations were moved to locations well west of 

Cross Island, the area where Nuiqsut-based whalers hunt for bowheads (Miller et al., 1999). 

Richardson provided a brief comparison between observations from seismic studies conducted in the 

1980’s and the 1996 seismic survey at the Arctic Seismic Synthesis Workshop in Barrow (USDOI, MMS, 

1997). Observations from earlier seismic studies during the summer and early autumn show that most 

bowhead whales interrupt their previous activities and swim strongly away when a seismic survey ship 

approaches within about 7.5-8 km. At the distances where this strong avoidance occurs, received levels of 

seismic pulses typically are high, about 150-180 dB re 1 μPa. The surfacing, respiration, and dive cycles of 

bowheads engaged in strong avoidance also change in a consistent pattern involving unusually short 

surfacing and diving and unusually few blows per surfacing. These avoidance and behavioral effects 

among bowheads close to seismic vessels are strong, reasonably consistent, and relatively easy to 

document. Less consistent and weaker disturbance effects probably extend to longer distances and lower 

received sound levels at least some of the time. Bowheads often tolerate much seismic noise and, at least in 

summer, continue to use areas where seismic exploration is common. 

At least one case of strong avoidance has been reported as far as 24 km from an approaching seismic boat 

(Koski and Johnson, 1987) and, as noted above, the aerial survey data (Miller et al., 1999) indicated that 

bowheads tended to avoid the area around the operating source, perhaps to a radius of about 20-30 km. 

Richardson noted that many of the observations involved bowheads that were not actively migrating. 

Actively migrating bowheads may react somewhat differently than bowheads engaged in feeding or 

socializing. Migrating bowheads, for instance, may react by deflecting their migration corridor away from 

the seismic vessel. Monitoring of the bowhead migration past a nearshore seismic operation in September 

1996 provided evidence consistent with the possibility that the closest whales may have been displaced 

several miles seaward during periods with seismic activity. 

With respect to these studies conducted in the Beaufort Sea from 1996-1998, the peer-review group at the 

Arctic Open-Water Noise Peer Review Workshop in Seattle from June 5-6, 2001, prepared a summary 

statement supporting the methods and results reported in Richardson (1999) concerning avoidance of 

seismic sounds by bowhead whales: 

Monitoring studies of 3-D seismic exploration (8-16 airguns totaling 560-1500 in3

) in the 

nearshore Beaufort Sea during 1996-1998 have demonstrated that nearly all bowhead whales will 

avoid an area within 20 km of an active seismic source, while deflection may begin at distances up 

to 35 km. Sound levels received by bowhead whales at 20 km ranged from 117-135 dB re 1 μPa 

 PEA-125 
rms and 107-126 dB re 1 μPa rms at 30 km. The received sound levels at 20-30 km are 

considerably lower levels than have previously been shown to elicit avoidance in bowhead or 

other baleen whales exposed to seismic pulses. 

A recent study in Canada provides information on the behavioral response of bowhead whales in feeding 

areas to seismic surveys (Miller and Davis, 2002). During the late summer and autumn of 2001, Anderson 

Resources Ltd. conducted an open-water seismic-exploration program offshore of the Mackenzie Delta in 

the Canadian Beaufort Sea. The program consisted of streamer seismic surveys and associated bathymetric 

surveys conducted off the Mackenzie Delta. The bathymetric surveys were conducted by two mediumsized vessels equipped with side-scan sonar and single-beam echosounders. The seismic vessel was the 

Geco Snapper. The acoustic sources used in the seismic operations were two 2,250-in3

 arrays of 24 sleevetype airguns. Each 2,250-in3

 airgun array was comprised of 24 airguns with volumes ranging from 40-150 

in3

. The two airgun arrays fired alternately every 8 seconds along the survey lines. The airgun arrays were 

operated at a depth of 5 m below the water surface. Water depths within the surveyed areas ranged from 6-

31 m and averaged 13 m (Miller, 2002). Because marine seismic projects using airgun arrays emit strong 

sounds into the water and have the potential to affect marine mammals, there was concern about the 

acoustic disturbance of marine mammals and the potential effects on the accessibility of marine mammals 

to subsistence hunters. Although there are no prescribed marine mammal and acoustic monitoring 

requirements for marine seismic programs in the Canadian Beaufort Sea, it was decided that monitoring 

and mitigation measures in the Canadian Beaufort Sea should be as rigorous as those designed and 

implemented for marine seismic programs conducted in the Alaskan Beaufort Sea in recent years. The 

monitoring program consisted of three primary components: acoustic measurements, vessel-based 

observations, and aerial surveys. The NMFS recommended criterion that exposure of whales to impulse 

sound not exceed 180 dB re 1μPa rms (65 FR 16374) was adopted as a mitigation standard for this 

monitoring program. Estimates of sound-propagation loss from the airgun array were used to determine the 

designated 1,000-m safety radius for whales (the estimated zone within which received levels of seismic 

noise were 180 dB re 1μPa rms or higher). 

Aerial and vessel-based surveys confirmed the presence of substantial numbers of bowheads offshore of the 

Mackenzie Delta from late August until mid-September. The distribution of bowheads in the study area 

was typical of patterns observed in other years and suggests that there were good feeding opportunities for 

bowheads in these waters during that period. 

A total of 262 bowheads were observed from the seismic vessel Geco Snapper (Moulton, Miller, and 

Serrano, 2002). Sighting rates during daylight hours were higher when no airguns were operating than 

during periods with airguns operating. During the period when bowheads were most abundant in the study 

area (August 23-September 19), the bowhead sighting rate during periods with no seismic (0.85 

bowheads/hour) was about twice as high as that recorded during periods with seismic (0.40 bowheads/hour) 

or all seismic operations combined (0.44 bowheads/hour). Average sighting distances from the vessel were 

significantly (P <0.001) lower during no airguns (a mean radial distance of 1,368 m) versus line-seismic 

periods (a mean radial distance of 1,957 m). The observed difference in sighting rates and the significant 

difference in sighting distances suggest that bowheads did avoid close approach to the area of seismic 

operations. However, the still substantial number of sightings during seismic periods and the relatively 

short (600 m) but significant difference in sighting distances suggests that the avoidance may have been 

localized and relatively small in nature. At a minimum, the distance by which bowheads avoided seismic 

operations was on the order of 600 m greater than the average distance by which they avoided general 

vessel operations. The lower sighting rates recorded during seismic operations suggest that some bowheads 

avoided the seismic operations by larger distances and, thereby, stayed out of visual range of the marine 

mammal observers on the Geco Snapper. 

In this study, a total of 275 bowhead whale sightings were recorded during aerial transects with good 

lighting conditions (Holst et al., 2002). Bowheads were sighted at similar rates with and without seismic, 

although the no feeding-seismic sample was too small for meaningful comparisons. Bowheads were seen 

regularly within 20 km of the operations area at times influenced by airgun pulses. Of 169 transect 

sightings in good conditions, 30 sightings were seen within 20 km of the airgun operations at distances of 

5.3-19.9 km. The aerial surveys were unable to document bowhead avoidance of the seismic operations 

area. The area of avoidance around the seismic operations area was apparently too small to be evident from 

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the broad-scale aerial surveys that were flown, especially considering the small amount of surveying done 

when seismic was not being conducted. General activities of bowheads during times when seismic 

operations were conducted were similar to times without seismic. 

The bowheads that surfaced closest to the vessel (323-614 m) would have been exposed to sound levels of 

about 180 dB re 1 μPa rms before the immediate shutdown of the array (Miller et al., 2002). There were 

seven shutdowns of the airgun array in response to sightings of bowheads within 1 km of the seismic 

vessel. Bowheads at the average vessel-based sighting distance (1,957 m) during line seismic would have 

been exposed to sound levels of about 170 dB re 1 μPa rms. The many aerial sightings of bowheads at 

distances from the vessel ranging from 5.3-19.9 km would have been exposed to sound levels ranging from 

approximately 150-130 dB re 1 μPa rms, respectively. 

The results from the study in summer 2001 are markedly different from those obtained during similar 

studies during the autumn migration of bowheads through the Alaskan Beaufort Sea (Miller et al., 2002). 

For example, during the Alaskan studies only 1 bowhead whale was observed from the seismic vessel(s) 

during six seasons (1996-2001) of vessel-based observations compared with 262 seen from the Geco 

Snapper in 2001. The zone of avoidance for bowhead whales around the airgun operations in 2001 was 

clearly much smaller (~2 km) than that observed for migrating bowhead whales in recent autumn studies in 

Alaskan waters (up to 20-30 km). Davis (1987) concluded that migrating bowheads during the fall 

migration may be more sensitive to industrial disturbance than bowheads on their summering grounds, 

where they may be engaged in feeding activities. 

Inupiat subsistence whalers have stated that industrial noise, especially noise due to seismic exploration, 

has displaced the fall bowhead migration seaward and, thereby, is interfering with the subsistence hunt at 

Barrow (Ahmaogak, 1989). Whalers have reported reaction distances, where whales begin to divert from 

their migratory path, on the order of 10 mi (T. Albert cited in USDOI, MMS, 1995a) to 35 mi (F. 

Kanayurak in USDOI, MMS, 1997. Kanayurak stated that the bowheads “...are displaced from their 

normal migratory path by as much as 30 miles.” Also at the March 1997 workshop, Mr. Roxy Oyagak, Jr., 

a Nuiqsut whaling captain, stated in written testimony: 

Based on the industrial activity, there is an unmitigable adverse impact on the village of Nuiqsut 

on subsistence whaling. i.e., 1) by causing the whales to abandon the hunting area ...and 3) 

placing physical barriers between the subsistence whalers and marine mammals, including altering 

the normal bowhead whale migration route. 

There also are data on the effect of seismic surveys on other species that are useful in interpretation of 

effects on baleen whales, including bowheads. Below, we review information from McCauley et al. (2000) 

regarding the responses of humpbacks to seismic surveys in Australia. More recently, at its minisymposium on acoustics in July 2004, the IWC Scientific Committee Standing Working Group on 

Environmental Concerns discussed information related to a stranding of humpbacks in Brazilian waters, 

coincident in time with seismic surveys in the area. During the 2002 breeding season, during the same time 

that seismic surveys were being conducted on breeding grounds in Brazilian waters, eight strandings of 

adult humpback whales were reported, a frequency nearly 27% of the total stranding of adults reported in 

Brazilian waters between 1975 and 2003. There was no clear cause of the stranding. They discussed also 

information related to a potential displacement by seismic surveys of western Pacific gray whales from a 

feeding area off of Sakhalin Island (IWC, 2004). Based on their discussions during the mini-symposium 

both the IWC as a whole and its Scientific Committee agreed that there is compelling evidence of 

increasing sound levels, including sound from ships and seismic activities. 

Weller et al. (2004) tested the hypothesis that the distribution of feeding western gray whales would shift 

away from seismic surveys by comparing the number of feeding western gray whales and the number of 

pods sighted during systematic scans conducted before, during, and after 3D seismic surveys. These 

authors found that both the number of whales and the number of pods sighted were significantly different 

during 3D seismic surveys than before and after the surveys. Noting that this population depends on the 

area studies for the majority of its annual food intake and is critically endangered, these authors (Weller et 

al., 2004:1) concluded that “Disruption of feeding in preferred areas is a biologically significant event that 

 PEA-127 
could have major negative effects on individual whales, their reproductive success, and thus the population 

as a whole.” 

Several summaries related to the potential effects of seismic surveys have been written (e.g., Richardson et 

al., 1995a; McCauley et al., 2000; Gordon et al., 1998, 2004). Gordon et al. (1998:Sec. 6.4.3.1) 

summarized that “Given the current state of knowledge, it is not possible to reach firm conclusions on the 

potential for seismic pulses to cause...hearing damage in marine mammals.” Later in this review, they 

reach the same conclusion about the state of knowledge about the potential to cause biologically significant 

masking. “This review has certainly emphasized the paucity of knowledge and the high level of 

uncertainty surrounding so many aspects of the effects of sound on marine mammals” (Gordon et al., 

1998:Sec. 6.12). While uncertainty is reduced, the statements above are still accurate. 

Seismic activity should have little effect on zooplankton. Bowheads feed on concentrations of 

zooplankton. Zooplankton that are very close to the seismic source may react to the shock wave, but little 

or no mortality is expected (LGL Ltd., 2001). A reaction by zooplankton to a seismic impulse would be 

relevant only if it caused a concentration of zooplankton to scatter. Pressure changes of sufficient 

magnitude to cause zooplankton to scatter probably would occur only if they were very close to the source. 

Impacts on zooplankton behavior are predicted to be negligible and would have negligible effects on 

feeding bowheads (LGL Ltd., 2001). 

Potential Differential Responses of Males and Females. McCauley et al. (2000) recently demonstrated that 

pods of humpback whales containing cows involved in resting behavior in key habitat were more sensitive 

to airgun noise than males and than pods of migrating humpbacks. In 16 approach trials carried out in 

Exmouth Gulf, off Australia, he found that pods of humpbacks with females consistently avoided a single 

(not an array) operating airgun at an average range of 1.3 km (McCauley et al., 2000). McCauley et al. 

(2000:692) summarized: 

The generalized response of migrating humpback whales to a three-dimensional seismic vessel 

was to take some avoidance maneuver at greater than 4 kilometers then to allow the seismic vessel 

to pass no closer than 3 kilometers. Humpback pods containing cows which were involved in 

resting behavior in key habitat types, as opposed to migrating animals, were more sensitive and 

showed an avoidance response estimated at 7-12 kilometers from a large seismic source. 

McCauley et al. (2000) observed a startle response in one instance. Within the key habitat areas where 

resting females and cow/calf pairs occurred, the humpbacks showed high levels of sensitivity to the airgun. 

The mean airgun level at which avoidance was observed was 140 dB re 1 μPa (rms), the mean standoff 

range was 143 dB re 1 μPa (rms), and the startle response was observed at 112 dB re 1 μPa (rms). Standoff 

ranges were 1.22-4.4 km. The noise levels at which response was detectable were less than those observed 

by McCauley et al. (2000) in observations made from the seismic vessel operating outside of the sensitive 

area where whales were migrating, not engaged in a sensitive activity. 

McCauley found that adult male humpbacks were much less sensitive to airgun noise than were females. 

At times, they approached the seismic vessel. McCauley et al. (2000) speculated that males that did so may 

have been attracted by the sound because of similarities between airgun sounds and breaching signals. 

Based on the aforementioned, it is likely that humpback whales feeding in areas within and adjacent to 

areas within the program area could have their movement and feeding behavior affected by noise associated 

with seismic exploration. The most likely to be impacted are cow/calf pairs. This potential impact would 

be seasonal, since humpbacks are not common in these areas during the winter. 

Conclusions about Potential Effects of 2D/3D Seismic. Scientific studies and traditional knowledge 

presented above about the potential effect of 2D/3D seismic surveys on bowheads indicate that bowhead 

response to 2D/3D seismic surveys varies, sometimes considerably. It is not entirely clear which factor(s) 

explain differences in response in all cases. However there appears to be a consensus that migratory 

bowheads may avoid an active seismic source at 20-30 km in some circumstance and deflection may start 

from even further (35 km). Because data on other whales and other mammals indicates that females with 

calves may show even stronger avoidance, and since it is often unclear what behavior a whale was engaged 

in, we assume most bowhead whale individuals may avoid an active vessel at received levels of as low as 

116-135 dB re 1 μPa (rms) when migrating, but acknowledge this zone avoidance may be considerably less 

for feeding whales. The 2D/3D seismic surveys may occur within multiple areas of the evaluation area, or 

 PEA-128 
there may be clustering of activities within more specific areas, for the entire open water period. We 

assume that seismic operators will be actively shooting as much of the open water period as is feasible. 

If bowhead whales, especially cow/calf pairs or large aggregations, avoided feeding or resting areas due to 

seismic-survey activities, there could be disruption of important biological behaviors of bowhead whales in 

that area. Our primary concern is for potential effects on calf survival and female reproduction. Given the 

state of the science on bowhead whales, it would be difficult, if not impossible, to determine if such 

exclusion in 2006 could result in lower calf survival, lower future reproduction, or reduced growth. 

Likewise, we cannot determine with certainty the potential energetic significance of exclusion of cow/calf 

pairs from resting areas, which could be significant if not mitigated. 

It is likely that one to four seismic surveys would occur anytime during the 2006 open water season, and 

bowheads may occupy some or all of these waters for much of this period. Because large aggregations 

have been observed in early September in some years in areas in the Alaskan Beaufort Sea, it is not clear if 

these whales (which have in some instances included a high proportion of cow/calf pairs) migrated west 

early, never migrated to feeding areas in the Canadian Beaufort Sea, or came in after summering in the 

Chukchi Sea. It is clear that some areas are used by larger numbers of whales on a regular basis, such as 

areas off of Dease Inlet and Smith Bay, Cape Halkett, and the areas near Brownlow Point (see Figure III.F6). 

Mitigations required in recent seismic surveys are designed primarily to reduce the potential for adverse 

effects on bowhead whale hearing and adverse effects on subsistence hunting of bowheads. Bowheads 

typically remain in portions of the Alaska Beaufort Sea after hunting in those areas is over. While we have 

uncertainty about their use of the northeastern Chukchi Sea in the summer and autumn, it is clear that they 

use the areas in periods and locations when and where there is no hunting. Because we are evaluating only 

the potential effects of seismic surveys that may occur in the 2006 open-water season, we conclude that 

available evidence does not indicate that exclusion or avoidance of adults from feeding or resting areas, 

would be likely to affect their survival. We also have identified mitigation that reduces the potential for 

adverse effects of exclusion or avoidance of feeding and resting areas. The MMS believes that, based on 

the best information available and the analysis based on it, the Proposed Action alternatives can be 

performed in an environmentally sound manner without generating significant impacts (see Sec. II). 

Additional resource-specific mitigation measures that would further reduce the potential for adverse effects 

have been identified through the PEA analysis (see Sec. IV). 

III.F.3.f(7) Effects of Noise from Icebreakers. If seismic-survey vessels are attended by icebreakers 

(serving as support vessels), additional disturbance and noise could be introduced by the icebreaker. We do 

not expect active ice management as part of this action in support of seismic surveying. Rather, if 

icebreaking occurs we expect it to occur only to permit vessel exit from the Beaufort and Chukchi seas. 

Because of this, we discuss the potential of icebreakers and icebreaking. 

Based on models in earlier studies, Miles, Malme and Richardson (1987) predicted that bowhead whales 

likely would respond to the sound of the attending icebreakers at distances of 2-25 km (1.24-15.53 mi) 

from the icebreakers (Miles, Malme, and Richardson, 1987). This study predicts that roughly half of the 

bowhead whales show avoidance response to an icebreaker underway in open water at a range of 2-12 km 

(1.25-7.46 mi) when the sound-to-noise ratio is 30 dB. The study also predicts that roughly half of the 

bowhead whales would show avoidance response to an icebreaker pushing ice at a range of 4.6-20 km 

(2.86-12.4 mi) when the sound-to-noise ratio is 30 dB. 

Table 6.5 in Richardson et al. (1995a) provided source levels at 1 meter for icebreaker noise. For example, 

they note that noise levels from the M/S Voima in open water at 50-60% power had broadband noise levels 

of 177 dB re 1 μPa-m whereas the source level when icebreaking full astern was 190 dB re 1 μPa-m. 

Response distances of bowheads to icebreakers are expected to vary, depending on the size, engine power, 

and mechanical characteristics of the icebreaker, vessel activities, sound-propagation conditions, the types 

of individuals exposed, and the activities they are engaged in when exposed. Richardson et al. (1995b) 

found that bowheads migrating in the nearshore lead often tolerated exposure to projected icebreaker 

sounds at received levels up to 20 dB or more above the natural ambient noise levels at corresponding 

frequencies. They pointed out that the source level of an actual icebreaker is much higher than that of the 

projectors (projecting recorded sound) used in their study (median difference 34 dB over the frequency 

 PEA-129 
range 40-6,300 Hz). Over the two-season period, they observed a difference in the estimated numbers of 

bowheads seen near the ice camp when the projects were quiet (approximately 158 bowheads in 116 

groups) versus when icebreaker sounds were being transmitted into the water (an estimated 93 bowheads in 

80 groups). Some but not all, bowheads diverted from their course when exposed to levels of projected 

icebreaker sound greater than 20 dB above the natural ambient noise level in the one-third octave band of 

the strongest icebreaker noise and a minority of whales apparently diverted at a lower sound-to-noise ratio. 

It should be noted that these predictions were based on reactions of whales to playbacks of icebreaker 

sounds in a lead system during the spring migration and are subject to a number of qualifications. For 

example, infrasounds that may be associated with icebreakers were not adequately represented in playback 

transmissions. Bowhead whales likely hear or can detect infrasounds (Richardson et al., 1995b). 

Richardson et al. (1995b:322) summarized that: 

The predicted typical radius of responsiveness around an icebreaker like the Robert Lemeur is 

quite variable, because propagation conditions and ambient noise vary with time and with 

location. In addition, icebreakers vary widely in engine power and thus noise output, with the 

Robert Lemeur being a relatively low-powered icebreaker. Furthermore, the reaction thresholds of 

individual whales vary by at least +10 dB around the “typical” threshold, with commensurate 

variability in predicted reaction radius. 

Richardson et al. (1995b:xxi) stated that: 

If bowheads react to an actual icebreaker at source to noise and RL values similar to those found 

during this study, they might commonly react at distances up to 10-50 km from the actual 

icebreaker, depending on many variables. Predicted reaction distances around an actual icebreaker 

far exceed those around an actual drillsite...because of (a) the high source levels of icebreakers and 

(b) the better propagation of sound from an icebreaker operating in water depths 40+ m than from 

a bottom-founded platform in shallower water. 

Richardson et al. (1995b) stated that predicted response distances for bowheads would be highly variable 

around an actual icebreaker. They predicted that detectable effects on behavior and movements for “typical 

traveling bowheads” extend commonly out to radii of 10-30 km (6.2-18.6 mi) and sometimes to 50+ km. 

They noted that given the factors influencing reaction distances and the observed reactions to playbacks of 

icebreaker noise “Predicted reaction distances for bowheads around an icebreaker like the Robert Lemeur

vary from as little as ~2 km to as much as 95 km.” 

Richardson et al. (1995b:xxii) concluded that 

...exposure to a single playback of variable icebreaker sounds can cause statistically but probably 

not biologically significant effects on movements and behavior of migrating bowheads visible in 

the open water of nearshore lead systems during spring migration east of Pt. Barrow. Reaction 

distances around an actual icebreaker like Robert Lemeur are predicted to be much greater, 

commonly on the order of 10-50 km. Effects of an actual icebreaker on migrating bowheads, 

especially mothers and calves, could be biologically significant. 

The highest potential for avoidance would probably occur if both seismic surveys and icebreaking occur 

within an area in which a high level of use by bowheads is also occurring. Because we do not expect ice 

management as part of the Proposed Action, we do not expect a significant effect on bowhead whales from 

icebreaker activities. Concerns also have been raised regarding the effects of noise from OCS exploration 

and production operations in the spring lead system and the potential for this noise to delay or block the 

bowhead spring migration. As stated previously, the general location of the spring lead system in the 

Beaufort Sea is based on relatively limited survey data and is not well defined. As specified above and in 

the mitigation measures of Section IV, MMS will not permit seismic surveys in the spring lead system until 

July 1 unless NMFS, during the process of consideration of an incidental take authorization request, 

determines that such a restriction is not required to reduce impacts to the bowhead migration, calving, 

cow/calf pairs, or bowhead calves. 

III.F.3.f(8) Effects from Other Vessel Traffic Associated with Seismic Surveys. According to Richardson 

and Malme (1993), most bowheads begin to swim rapidly away when vessels approach rapidly and 

 PEA-130 
directly. This avoidance may be related to the fact that bowheads have been commercially hunted within 

the lifetimes of some individuals within the population and they continue to be hunted for subsistence 

throughout many parts of their range. Avoidance usually begins when a rapidly approaching vessel is 1-4 

km (0.62-2.5 mi) away. A few whales may react at distances from 5-7 km (3-4 mi), and a few whales may 

not react until the vessel is <1 km (<0.62 mi) away. Received noise levels as low as 84 dB re 1 μPa (rms) 

or 6 dB above ambient may elicit strong avoidance of an approaching vessel at a distance of 4 km (2.5 mi) 

(Richardson and Malme, 1993). 

In the Canadian Beaufort Sea, bowheads observed in vessel-disturbance experiments began to orient away 

from an oncoming vessel at a range of 2-4 km (1.2-2.5 mi) and to move away at increased speeds when 

approached closer than 2 km (1.2 mi) (Richardson and Malme, 1993). Vessel disturbance during these 

experimental conditions temporarily disrupted activities and sometimes disrupted social groups, when 

groups of whales scattered as a vessel approached. Reactions to slow-moving vessels, especially if they do 

not approach directly, are much less dramatic. Bowheads often are more tolerant of vessels moving slowly 

or in directions other than toward the whales. Fleeing from a vessel generally stopped within minutes after 

the vessel passed, but scattering may persist for a longer period. After some disturbance incidents, at least 

some bowheads returned to their original locations (Richardson and Malme, 1993). Some whales may 

exhibit subtle changes in their surfacing and blow cycles, while others appear to be unaffected. Bowheads 

actively engaged in social interactions or mating may be less responsive to vessels. 

Data are not sufficient to determine sex, age, or reproductive factors that may be involved in response to 

vessels. We are not aware of data that would allow us to determine whether females with calves tend to 

show avoidance and scattering at a greater, lesser, or at the same distances as other segments of the 

population. 

The encounter rate of bowhead whales with vessels associated with exploration would be determined by 

what areas were being explored. Given the proposed scenario of up to four seismic surveys in each of the 

two planning areas, there could potentially be up to eight additional support vessels, some of which could 

be icebreakers, in the vicinity where seismic activity may occur. Data are insufficient for us to accurately 

predict the average geographic zone of activity by the support vessels and thus, to predict the additional 

area that could be affected by the vessels. 

Bowhead whales could encounter noise and disturbance from multiple seismic vessels and multiple support 

vessels as they migrate and feed in the Beaufort and Chukchi seas. The significance of such encounters is 

expected to depend on the area in which the vessels are transiting, the total number of vessels in the area, 

the presence of other vessels (see cumulative effects section), and variable already identified regarding the 

number, behavior, age, sex and reproductive condition of the whales. 

Depending on ice conditions, it is likely that vessels moving from one site to another would be more 

disturbing to whales than vessels idling or maintaining their position. Bowheads probably would adjust 

their individual swimming paths to avoid approaching within several to several dozen kilometers. Vessel 

activities associated with seismic surveys are not expected to disrupt the bowhead migration but may cause 

avoidance of certain areas. Small deflections in individual bowhead-swimming paths are not expected to 

be significant in any individuals but a reduction in use of possible bowhead-feeding areas near exploration 

units may result in adverse effects. During their spring migration (April through June), bowheads likely 

would encounter few, if any, vessels along their migration route, because ice at this time of year typically 

would be areally extensive and too thick for seismic-survey ships and supply vessels to operate in. Because 

MMS is not allowing seismic-survey activities in the spring lead system until July 1 unless authorized by 

NMFS, we do not expect seismic survey vessel interaction to be an important source of disturbance during 

the northward migration. 

In addition to acting as a source of noise and disturbance, marine vessels could potentially strike bowhead 

whales, causing injury or death. As noted in the cumulative effects section of this PEA, available 

information indicates that current rates of vessel strikes of bowheads are low. Available data do not 

indicate that strikes of bowheads by seismic-survey-related vessels will become an important source of 

injury or mortality. 

III.F.3.f (9) Effects from Aircraft Traffic. Underwater sounds from aircraft are transient. According to 

Richardson et al. (1995a), the angle at which a line from the aircraft to the receiver intersects the water s 

 PEA-131 
surface is important. At angles greater than 13 degrees from the vertical, much of the incident sound is 

reflected and does not penetrate into the water. Therefore, strong underwater sounds are detectable while 

the aircraft is within a 26-degree cone above the receiver. An aircraft usually can be heard in the air well 

before and after the brief period while it passes overhead and is heard underwater. 

Data on reactions of bowheads to helicopters are limited. Most bowheads are unlikely to react significantly 

to occasional single passes by low-flying helicopters ferrying personnel and equipment to offshore 

operations. Observations of bowhead whales exposed to helicopter overflights indicate that most bowheads 

exhibited no obvious response to helicopter overflights at altitudes above 150 m (500 ft). At altitudes 

below 150 m (500 ft), some bowheads probably would dive quickly in response to the aircraft noise 

(Richardson and Malme, 1993). This noise generally is audible for only a brief time (tens of seconds) if the 

aircraft remains on a direct course, and the whales should resume their normal activities within minutes. 

Patenaude et al. (1997) found that most reactions by bowheads to a Bell 212 helicopter occurred when the 

helicopter was at altitudes of 150 m (500 ft) or less and lateral distances of 250 m or less. The most 

common reactions were abrupt dives and shortened surface time and most, if not all, reactions seemed 

brief. The majority of bowheads, however, showed no obvious reaction to single passes, even at those 

distances. The helicopter sounds measured underwater at depths of 3 and 18 m showed that sound 

consisted mainly of main-rotor tones ahead of the aircraft and tail-rotor sounds behind the aircraft; more 

sound pressure was received at 3 m than at 18 m; and peak sound levels received underwater diminished 

with increasing aircraft altitude. Sound levels received underwater at 3 m from a Bell 212 flying overhead 

at 150 m (500 ft) ranged from 117-120 dB re 1μPa in the 10-500-Hz band. Underwater sound levels at 18 

m from a Bell 212 flying overhead at 150 m ranged from 112-116 dB re 1 μPa in the 10-500-Hz band. 

Fixed-wing aircraft flying at low altitude often cause hasty dives. Reactions to circling aircraft are 

sometimes conspicuous if the aircraft is below 300 m (1,000 ft), uncommon at 460 m (1,500 ft), and 

generally undetectable at 600 m (2,000 ft). Repeated low-altitude overflights at 150 m (500 ft) during 

aerial photogrammetry studies of feeding bowheads sometimes caused abrupt turns and hasty dives 

(Richardson and Malme, 1993). Aircraft on a direct course usually produce audible noise for only tens of 

seconds, and the whales are likely to resume their normal activities within minutes (Richardson and Malme, 

1993). Patenaude et al. (1997) found that few bowheads (2.2%) during the spring migration were observed 

to react to Twin Otter overflights at altitudes of 60-460 m. Reaction frequency diminished with increasing 

lateral distance and with increasing altitude. Most observed reactions by bowheads occurred when the 

Twin Otter was at altitudes of 182 m or less and lateral distances of 250 m or less. There was little, if any, 

reaction by bowheads when the aircraft circled at an altitude of 460 m and a radius of 1 km. The effects 

from an encounter with aircraft are brief, and the whales should resume their normal activities within 

minutes. 

While the obvious behavioral reaction of a bowhead to a single low-flying helicopter or fixed-winged 

aircraft flying overhead is probably temporary (Richardson et al., 1995a), most “fleeing” reactions in 

mammals area accompanied by endocrine changes, which, depending on other stressors to which the 

individual is exposed, could contribute to a potentially adverse effect on health. 

The greatest potential for helicopter or fixed-wing aircraft to cause adverse effects on bowhead whales 

exists in areas where bowheads are aggregated, especially if such aggregations contain large numbers of 

cow/calf pairs. We discuss these areas at the end of our discussion of the potential effects of particular 

affecters. 

Such potential fleeing reactions would likely be considered in incidental take authorizations. Flight 

practices could be structured by the helicopter operators to avoid such interactions. Potential effects on 

bowheads from aircraft are relatively easily avoided by flight practices requiring fixed winged flights above 

1,000 feet avoidance by helicopters of areas where bowheads are aggregated. 

III.F.3.f(10) Areas and Situations Where Potential Impacts are Likely to be Greater than Typical. 

Bowheads are not randomly distributed throughout the two evaluation areas. The extent of use of particular 

habitats varies among years, sometimes considerably. We cannot predict, in advance of a given year, 

exactly how bowheads will use the entire area that is available to them. Some aspects of their habitat use 

are poorly understood. For example, current data are not available on which to typify the current summer 

use of the northern Chukchi Sea by bowheads and even summer use of the Beaufort Sea is not well 

understood. For example, in some years, large aggregations of bowheads near Smith Bay have been 

 PEA-132 
observed during MMS’ Bowhead Whale Aerial Survey Program (BWASP) surveys at the beginning of 

September. It is unclear if these animals are early migrants that have come from the east, if they summered 

in the northern portions of the Beaufort Sea and came south, or if they entered from the Chukchi Sea and 

never migrated east. It is unclear if these whales could be expected to be present in mid- to late-August. 

We depict counts from the aerial surveys in the Beaufort Sea on Figure III.F-6. This figure clearly shows 

areas of relatively high use by bowheads, and thus, areas where effects from the proposed seismic surveys 

are likely to be greater than typical. Figure III.F-7 depicts counts in the Chukchi Sea. It is important to 

note that the Chukchi Sea data are not recent (1979-1991) and thus should not be interpreted as indicating 

current patterns of bowhead use of the Chukchi Sea. While it is clear that seismic activity may overlap 

with bowhead use of the Chukchi Sea during fall migration, we are highly uncertain about the likely extent 

of overlap between seismic activity and bowhead whales in the summer. During fall migration, available, 

but dated, data indicate that overlap is likely to be greatest in the main migratory pathways, one heading 

nearly directly to the Bering Strait, and the other heading west from Barrow towards Wrangell Island (see 

Figure III.F-5). 

It is clear that if 2D/3D seismic surveys impacted areas of the spring lead and polynya system during the 

spring migration, impacts could potentially be biologically significant. We note that the general location of 

the spring lead system in the Chukchi and Beaufort seas is based on relatively limited survey data and is not 

well defined. Noise-producing activities, such as seismic surveys, in the spring lead system during the 

spring bowhead migration have a fairly high potential of affecting the whales including females with 

newborn calves. We do not expect this to occur, because MMS will not permit seismic surveys in this 

system through the end of June. Thus, seismic surveys are not expected to be conducted in or near the 

spring lead system through which bowheads migrate because (1) degraded ice conditions would not allow 

on-ice surveys, (2) sufficient open water may not be present for open-water seismic surveys, and (3) MMS 

will not permit surveys in the lead system until July 1 unless authorized by NMFS. 

Data available from MMS’ BWASP surveys over about a 27-year period indicate that, at least during the 

primary open water period during the autumn (when open water seismic activities are most likely to occur), 

there are areas where bowheads are much more likely to be encountered and where aggregations, including 

feeding aggregations and/or aggregations with large numbers of cow/calf pairs, are more likely to occur in 

the Beaufort Sea (Figure III.F-6). Such areas include the areas north of Dease Inlet to Smith Bay, northeast 

of Smith Bay, and Northeast of Cape Halkett, as well as areas near Brownlow Point. 

Such aggregations have been observed in multiple years during BWASP surveys. While Figure III.F-6 is 

simply intended to show relative use of various areas over many years and using many years of data, 

groups of more than 50 or more whales have been seen on many single occasions (see data summarized in 

Treacy, 2002; Monnett and Treacy, 2005). For example, Treacy (1998) observed large feeding 

aggregations, including relatively large numbers of calves (for example, groups of 77[6], 62[5], 57[7], and 

51[0], where the numbers given in brackets are the numbers of calves) of feeding bowheads in waters off of 

Dease Inlet/Smith Bay in 1997 and in 1998. In some years no large aggregations of bowheads were seen 

anywhere within the study area. When seen, the aggregations were in open water. As BWASP survey 

coverage is approximately 10% of the area surveyed, numbers counted are only a fraction of the numbers 

of whales that may be present. 

If 2D/3D seismic surveys occurred in these areas when large aggregations were present, and particularly if 

multiple 2D/3D seismic surveys occurred concurrently in these areas, large numbers (hundreds) of 

bowheads could potentially be disturbed by the survey activity or could be excluded by avoidance from 

habitat for the period the surveys were occurring. As we explain in the description of the Proposed Action, 

the time frame over which 2D/3D seismic surveys are likely to occur in a given area is variable, depending 

on the size of the area being surveyed as well as the percentage of time when the boat is inactive. 

However, it would not be atypical for a seismic vessel to be in a given area for 20-30 days. Following the 

recommendation of the NRC (2005) regarding the expression of the length of period of a potential 

disturbance or behavioral impacts in migratory species be expressed in the context of how long the total 

period of potential use of the area is, we note that the period of just a single 3-D seismic survey could be 

half or more of the bowhead Beaufort Sea open water autumn migration/autumn feeding habitat use period. 

If another company is interested in the same area (this is especially likely to occur in the Chukchi Sea 

evaluation area where there are no active leases) seismic survey activities could potentially exclude, 

 PEA-133 
through avoidance, bowhead whales from areas for the entire Beaufort Sea open-water autumn 

migration/autumn feeding period. We do not mean to infer that individual whales do, or do not, use some 

of these high use areas for this entire autumn open water period. Data are not sufficient to permit us to 

determine whether or not that is true. Data do indicate that, in some cases either hundreds of whales could 

be excluded (through avoidance) from a large area for a relatively long portion of the season, or many more 

individuals would likely avoid the area as they sequentially came in to use the area. The mitigation 

measures outlined in Section IV and those included as part of the MMPA authorization process are 

designed to avoid Level A takes (injury) and limit the potential for Level B takes (harassment) to ensure a 

negligible impact on marine mammals, including bowhead whales. 

Considering only seismic activity, and ignoring other potential human uses of an area, we considered a 

relatively crude scenario where all four seismic vessels in a given area were interested in collecting seismic 

data from the same general area. This admittedly simplistic scenario does not include any avoidance of 

support vessels, attraction of prey that might be in the area, sizes of the areas being surveyed, turning 

requirements for the vessels, or the fact that, unless the vessels all moved in tandem, this area would be 

larger if the vessels moved further apart. The scenario does provide an opportunity for obtaining a 

simplistic area of avoidance under the following assumptions: (1) the seismic vessels are no more distant 

from each other than the minimum separation of 15 mi that MMS requires; and (2) most bowhead whales 

may avoid approaching an active seismic vessel from a distance of about 20-30 km (e.g., see study results 

provided above and summary in Appendix A of LGL Alaska Research Assocs. and LGL Ltd., 2005), the 

distance exhibited by migrating bowhead whales in response to OBC seismic surveys in the Alaskan 

Beaufort Sea at estimated received levels of about 116-135 dB re 1 μPa rms. We caution that this exercise 

is simply an attempt to gauge an approximate “ballpark” idea of the extent of the area that might be 

avoided. Data indicate that bowhead reaction to seismic impacts varies, and could be lower in some cases 

if bowheads are in an area feeding (e.g., strong avoidance at ~3-7 km) (e.g., see Richardson, Würsig, and 

Greene, 1986; Richardson et al., 1995a), but could also be higher during migration (e.g., up to 35 km in 

some cases), especially if much larger air guns were used than those used in surveys in the Beaufort during 

the late 1990’s. Given these assumptions, an instantaneous area being avoided by bowheads in all 

directions could be as much as 112-132 km x 40-60 km. On Figures III.F-10 and III.F-11, we have 

attempted to portray such an area (using the 112 x 40 km values in both cases) relatively near Barrow and 

near areas of relatively high whale use, to get a gross idea of the potential for high level impacts. If one 

mentally moves this rectangle (in reality, this would be not be rectangular, especially on the ends) 

throughout the two evaluation areas, one can get a crude idea of the potential extent of avoidance in 

different areas if the assumptions, as discussed above, held. If the area of activity and the rectangle of 

avoidance were offshore of where the whales wanted to be, but not far offshore, the seismic vessels might 

form a “seismic fence” over which few whales would cross. It is likely most of the whales would not make 

use of the areas inshore of the “seismic fence,” and instead move seaward of the seismic activity. If 

seismic surveying is being conducted in relatively nearshore blocks (e.g., within 20-30 km of wherever the 

bowheads’ most shoreward-migratory pathway would be), seaward movement could be constrained by the 

presence of offshore ice. The mitigation measures outlined in Sections II and IV and those included 

through the MMPA authorization process are designed to limit the potential for seismic surveys to 

adversely affect the bowhead whales and the subsistence hunt. The MMS and NMFS can restrict 

operations if additive synergistic effects occur from simultaneous seismic surveys that might hinder the 

whales’ migration. 

Such clumping of activities could occur, if different companies were all interested in a similar geological 

prospect and were spaced as near to one another as MMS requirements would allow. If restrictions were 

put on the number of operators that could operate simultaneously, within a single season, within a specified 

geographic area, the total area in the evaluation area excluded by avoidance would rise, but the 

simultaneous geographic impacts in a given area would be lessened. This potential strategy trade-off could 

be important in reducing effects in high value areas. 

We are aware that the extent of avoidance will vary both due to the actual noise level radii around each 

seismic vessel, the context in which it is heard, and the motivation of the animal to stay within the area. It 

may also vary depending on the age, and most likely, the sex and reproductive status of the whale. It may 

be related to whether subsistence hunting has begun and/or is ongoing. 

 PEA-134 
Because the areas where large aggregations of whales have been observed during the autumn are also areas 

used, at least in some years, for feeding, it may be that the whales would show avoidance more similar to 

that observed in studies of whales on their summer feeding grounds. As we noted above, it is not clear that 

reduced avoidance should be interpreted as a reduction in impact. It may be that bowheads are so highly 

motivated to stay on a feeding ground that they remain at noise levels that could, with long term exposure, 

cause adverse effects. 

We also acknowledge that effects could be greater than anticipated in two situations in the Chukchi Sea. 

The first situation could arise in the summer if bowheads use the Chukchi Sea in the summer more than is 

commonly assumed, especially for feeding and if large numbers of cow/calf pairs remain in the Chukchi 

Sea. The second situation for possibly larger than typical impacts exists in the Chukchi Sea in the autumn 

(e.g., late September on) as whales migrate both towards the Asian coast and toward the Bering Strait. We 

do not have sufficient data to determine the current migration paths or the numbers of whales that might be 

deflected from those paths. Data are not available to determine how intensively bowheads feed during the 

autumn migration in the Chukchi Sea or whether large aggregations exist in certain places due prey 

resources. Because recent data are not available on which to evaluate current habitat use by season or area 

in the Chukchi Sea, the mitigation measures in Section IV.A should provide additional environmental 

protection to large numbers of feeding whales and cow/calf pairs by further reducing potential adverse 

effects.. 

III.F.3.f(11) Summary of Noise Effects Associated with Seismic Surveys. Our primary concern is for 

potential effects on bowhead whales, especially cow/calf pairs, newborn and other calves, and females in 

general. If females are unaccompanied by calves they cannot be distinguished from males. If seismic 

surveys resulted in the exclusion of large numbers of these classes of individuals from feeding areas, or if 

calves were exposed to loud sounds from seismic surveys, we cannot rule out the potential for affecting 

biologically important behaviors. We believe the potential for such effects can be greatly reduced or 

avoided through careful application of mitigating measures as outlined in Section IV. 

The observed response of bowhead whales to seismic noise has varied among studies. Some of the 

variability appears to be context specific (i.e., feeding versus migrating whales) and also may be related to 

reproductive status and/or sex or age. Feeding bowheads tend to show less avoidance of sound sources 

than do migrating bowheads. This tolerance should not be interpreted as clear indication that they are not, 

or are, affected by the noise. Their motivation to remain feeding may outweigh any discomfort or normal 

response to leave the area. They could be suffering increased stress from staying where there is very loud 

noise. However, data on other species, and behavioral literature on other mammals, indicates that females 

with young are likely to show greater avoidance of noise and disturbance sources, than will juvenile or 

adult males. 

Recent monitoring studies (1996-1998) and traditional knowledge indicate that during the fall migration, 

most bowhead whales avoid an area around a seismic vessel operating in nearshore waters by a radius of 

about 20-30 km, with received sound levels of 116-135 dB re 1 μPa (rms). Some bowheads began 

avoidance at greater distances (35 km). Few bowheads approached the vessel within 20 km (12.4 mi). 

This is a larger avoidance radius than was observed from scientific studies conducted in the 1980’s. 

Avoidance did not persist beyond 12-24 hours after the end of seismic operations. In early studies, 

bowheads also exhibited tendencies for reduced surfacing and dive duration, fewer blows per surfacing, 

and longer intervals between successive blows. Available data indicate that behavioral changes are 

temporary. There is concern within the subsistence whaling communities that whales exposed to this 

source of noise (and other sources) may become more sensitive, at least over the short term, to other noise 

sources. 

If icebreakers attended seismic vessels, it is possible that roughly half of the bowheads would respond at a 

distance of 4.6-20 km (2.86-12.4 mi) when the sound-to-noise ratio is 30 dB. Whales appear to exhibit less 

avoidance behavior with stationary sources of relatively constant noise than with moving sound sources. 

Bowheads do not typically respond to aircraft overflights at altitudes above 300 m (984 ft). Below this 

altitude, some changes in whale behavior may occur, depending on the type of plane and the 

responsiveness of the whales present in the vicinity of the aircraft. The behavioral effects from such an 

encounter with either fixed-wing aircraft or helicopters generally are brief, and the whales should resume 

their normal activities within minutes. Bowheads may exhibit strong temporary avoidance behavior if 

 PEA-135 
approached by vessels at a distance of 1-4 km (0.62-2.5 mi). Fleeing behavior from vessel traffic generally 

stopped within minutes after the vessel passed, but scattering may persist for a longer period. In some 

instances, at least some bowheads returned to their original locations. Repeated encounters with aircraft 

and/or vessels that caused panicked or “fleeing” behavior, could result repeated temporary physiological 

stress reactions, which could have adverse effects on health over time. In many cases, vessel activities are 

likely to be in shallow, nearshore waters outside the main bowhead-migration route. 

Occasional brief interruption of feeding by a passing vessel or aircraft probably is not significant. The 

importance of a given high-use feeding area (especially those in the western Alaskan Beaufort Sea) in a 

given year to the total energetics of specific classes of individuals is still highly uncertain. Following the 

guidance of the NRC (2005), we have looked at these possible disturbances in the context of the total time 

the whales have to feed on their high latitude grounds and the time they spend in migration. The energetic 

cost of traveling a few additional kilometers to avoid closely approaching a noise source is very small in 

comparison with the cost of migration between the central Bering and eastern Beaufort seas. While MMS 

previously (USDOI, MMS, 2003a) concluded that these disturbances or avoidance factors were unlikely to 

be significant, the anticipated level of activity in 2006 is greater than in 2003 but less than the activities in 

the late 1970’s and 1980’s. Behavioral studies have suggested that bowheads habituate to noise from 

distant, ongoing drilling or seismic operations (Richardson et al., 1985a), but there still is some apparent 

localized avoidance (Davis, 1987). 

III.F.3.f(12) Effects from Small Oil Spills Associated with Seismic Surveys. Large oil spills are not 

expected during the course of exploration. Small fuel spills associated with the vessels used for seismic 

exploration could occur, especially during fuel transfer. There could be localized short-term alterations in 

bowhead habitat and bowhead habitat use as a result of such a spill. Whales exposed to a small fuel spill 

likely would experience temporary or potentially permanent nonlethal effects. Data available from other 

mammals indicates that prolonged exposure, or particularly exposure of nursing young to spilled oil, could 

potentially result in temporary or potentially permanent sublethal effects. For example, ingestion of oil 

reduces food assimilation and thereby reduces the nutritional value of food. However, it is unlikely such an 

impact would be detectable. These conclusions are supported by the best available information. There are 

no data available to MMS that definitely link even a large oil spill with a significant population-level effect 

on a species of large cetacean. The greatest potential for an adverse effect would be if a large fuel spill 

(e.g., due to vessel sinking) occurred in the Chukchi Sea and affected the spring lead system. The potential 

for there to be adverse effects from a fuel oil spill would also likely be greater (than in more typical 

circumstances) if a large spill of fuel oil (with high concentrations of aromatics) contacted one or more 

large aggregation of bowheads. The probability of such an accident occurring and affecting this habitat is 

unlikely. 

Copepods may passively accumulate aqueous polyaromatic compounds (PAC’s) from water and could 

thereby serve as a conduit for the transfer of PAC’s to higher trophic level consumers. Bioaccumulation 

factors were ~2000 for M. okhotensis and about ~8000 for C. marshallae. Calanus and Neocalanus

copepods have relatively higher (Duesterloh, Short, and Barron, 2002). A small fuel spill would not 

permanently affect zooplankton populations, the bowhead’s major food source. The amount of 

zooplankton lost in a small fuel spill would be small compared to what is available on the whales’ summerfeeding grounds (Bratton et al., 1993). 

The potential effects to bowheads of exposure to PAC’s through their food are unknown. Because of their 

extreme longevity, bowheads are vulnerable to incremental long-term accumulation of pollutants. With 

increasing development within their range and long-distance transport of other pollutants, individual 

bowheads may experience multiple large and small polluting events within their lifetime. 

In the Biological Opinion for Federal oil and gas leasing and exploration by the MMS within the Alaskan 

Beaufort Sea, and its effects on the endangered bowhead whale, the NMFS (2001:51) stated that: 

It is difficult to accurately predict the effects of oil on bowhead whales (or any cetacean) because 

of a lack of data on the metabolism of this species and because of inconclusive results of 

examinations of baleen whales found dead after major oil releases. 

We provide extensive review and discussion of potential impacts of oil spills on endangered whales in our 

Biological Evaluation of Potential Effects of Oil and Gas Activities in the Chukchi Sea and Beaufort Sea 

 PEA-136 
Program Areas on Bowhead, Fin and Humpback Whales. This document is provided on our website at 

http://www.mms.gov/alaska. 

We conclude that there could potentially be displacement of bowhead whales from a local feeding area 

following a fuel spill, and this displacement could last as long as there is a large amount of oil and related 

cleanup-vessel activity. Individual bowhead whales potentially could be exposed to spilled fuel oil, and 

this exposure could have short-term effects on health. Outside of a major fuel spill resulting from a vessel 

sinking, we expect seismic-survey spill-related effects to be minor. 

III.F.3.f(13) Evaluation of the Context and Intensity of the Proposed Action Relative to Bowhead 

Whales. 

III.F.3.f(13)(a) Unique Characteristics of the Geographic Area. We provide detailed information about 

the affected environment and bowhead whales in Section III.F.3.a through c. The original affected 

environment in which this activity could have occurred included areas within the spring migratory pathway 

of the bowhead whale in the Chukchi and Beaufort seas; bowhead calving areas; the fall migratory pathway 

of the bowhead; and spring, summer, and fall bowhead feeding grounds. Mating can occur within the 

Beaufort and Chukchi seas area, but most mating probably occurs in the Bering Sea. 

We have attempted to reduce substantially the potential for there to be any significant effects on bowhead 

calving by building into the base action a ban on the conduct of seismic surveys within the spring lead 

system until July 1 unless authorized by NMFS. Thus, seismic surveys will not be permitted to begin 

operations until July 1 unless authorized by NMFS. While some calving may occur after this date, 

available data indicate that most of the calving has occurred before that time. This ban also should 

significantly reduce the possibility of dispersal or disruption of whales that are feeding within the spring 

lead system in the Chukchi Sea. 

Thus, because of these mitigations, the spring lead system with in the Chukchi Sea until July 1 is removed 

from the affected environment in which this action could now occur. 

Where data are available and sufficient, we have attempted to identify other areas where aggregations of 

bowheads are known to occur and where feeding aggregations repeatedly have been observed. We have 

summarized information that is available about the timing of habitat use. 

Where analyses identified areas where effects to bowheads potentially could be significant, we have 

identified monitoring and mitigation measures to reduce the potential for such impacts (see Section IV). 

III.F.3.f(13)(b) Degree of Controversy. There is lack of agreement and controversy within the scientific 

and stakeholder communities about the potential effects of noise on baleen whales, including bowhead 

whales. This was demonstrated recently by summaries provided in the NRC (2005) and by the lack of 

consensus amongst participants in the Marine Mammal Commission’s Sound Advisory Panel (USDOI, 

MMS, 2006). We have considered and incorporated recommendations from the NRC (2005) in our 

analyses and our conclusions about the potential significance of effects. Perhaps more importantly, our 

analyses are cautious in that we have attempted to err on the side of overestimating potential effects rather 

than underestimating, and then building in mitigations to reduce such potential effects.

III.F.3.f(13)(c) Degree of Highly Uncertain Effects or Unique or Unknown Risks. As discussed in the 

affected environment section and summarized in the effects of the Proposed Action section, there are 

limited recent data and, hence, uncertainty, on the current use of the Chukchi Sea by bowhead whales after 

the primary spring migration period (until approximately June 15 in most years). There is some, but less 

uncertainty about bowhead use of the Beaufort Sea for feeding during the summer before September 1. 

There is remaining uncertainty about the importance of feeding areas within the Alaska Beaufort Sea, 

especially the western Alaskan Beaufort Sea, to the bowhead population as a whole and, more specifically, 

to certain segments of the population. While it is clear that there is considerable interannual variability in 

the use of the Beaufort Sea for feeding by bowheads, the factors underlying such variability are not entirely 

clear. More importantly, the importance of the areas to segments of the population and to the population as 

 PEA-137 
a whole during years when large aggregations are observed feeding is unclear. There also is uncertainty 

about the potential effects of such disturbance to the health of females and young calves and to the next 

year’s reproductive potential of adult females. There is uncertainty about the effects of sound on the 

hearing of very young calves. In our analyses, we acknowledge this uncertainty and, where it exists, we 

have designed mitigations aimed at reducing this uncertainty and to reduce the potential for there to be 

adverse effects on bowhead whales, especially cow/calf pairs. 

III.F.3.f(13)(d) Precedent-Setting Effects. This PEA evaluates the potential effects of seismic-survey 

activities that could occur in the 2006 open-water season in the Arctic Ocean. Regarding bowhead whales, 

there is extensive history and regulatory and procedural structure to evaluate the possible effects of seismicsurvey noise on bowhead whales. For this reason, we do not believe that actions taken in 2006 are likely to 

be precedent setting in any other planning areas or with any other species.. 

III.F.3.f(13)(e) Cumulative Effects. There are potential cumulative effects of noise on bowhead whales. 

For this reason, we have addressed these potential effects in the cumulative effects section of this document 

(Section III.H). 

III.F.3.f(13)(f) Violations of Federal, State, or Local Environmental Law. If seismic surveys were 

conducted without authorization under the MMPA, violations of the MMPA and the ESA could result. The 

Proposed Action and the further considered Alternatives 3 through 6 all require that operators obtain 

MMPA authorization prior to the commencement of survey activity authorized under MMS permits. For 

this reason, we can rule out violations of the MMPA and ESA. 

III.F.3.f(14) Conclusions about Potential Effects of Seismic Surveys on Bowhead Whales. Available 

information indicates that bowhead whales are responsive, in some cases highly responsive, to 

anthropogenic noise in their environment. At present, the primary response that has been documented is 

avoidance, sometimes at considerable distance. Response is variable, even to a particular noise source, and 

the reasons for this variability are not fully understood. In other species of mammals, including cetaceans, 

females with young are more responsive to noise and human disturbance than other segments of the 

population (McCauley et al., 2000). 

Data are sufficient to conclude that all response to future noise and disturbance is likely to vary with time 

of year; sex and reproductive status of individuals exposed; site (because of differences in noise 

propagation and use by bowheads); activity levels and the exact characteristics of that activity (e.g., airgun 

source levels, array configuration and placement in the water column; context (e.g., feeding versus 

migrating whales); the animal’s motivation to be in an area; and options for alternative routes, places to 

feed, etc. While habituation is seen in some species, and behavioral studies have suggested that bowheads 

habituate to noise from distant, ongoing drilling or seismic operations, localized avoidance still occurred. 

We believe that it is much less likely that bowheads will habituate to at least certain types of noise within a 

relatively large distance than some other species, because they are hunted annually; some individual may 

have been exposed to both commercial and subsistence hunting over the course of many years and, thus, 

many individuals may have a strong negative association with human noise. 

Bowhead whales that may be exposed to 2D/3D seismic surveys most likely would exhibit avoidance of 

such operations, and in so doing, avoid the potential for any harm to their hearing from the noise. 

However, data indicate that fall migrating bowheads can show greater avoidance of active seismic vessels 

than do feeding bowheads. Recent monitoring studies (1996-1998) and traditional knowledge indicate that 

during the fall migration, most bowhead whales avoid an area around a seismic vessel operating in 

nearshore waters by a radius of about 20-30 km and may begin avoidance at greater distances. Received 

sound levels at 20 km ranged from 117-135 dB re 1 μPa rms and 107-126 dB re 1μ Pa rms at 30 km. This 

is a larger avoidance radius than was observed from scientific studies conducted in the 1980’s. Avoidance 

did not persist beyond 12-24 hours after the end of seismic operations. In some early studies, bowheads 

also exhibited tendencies for reduced surfacing and dive duration, fewer blows per surfacing, and longer 

intervals between successive blows. Available data indicate that behavioral changes are temporary. The 

subsistence-whaling communities are substantially concerned that whales exposed to this source of noise 

(and other sources) may become more sensitive, at least over the short term, to other noise sources. 

Potential impacts to the population would be related to the numbers and types of individuals that were 

 PEA-138 
affected (e.g., juvenile males versus females with calves). Activities that cause active avoidance over large 

distances will have the effect of reducing rest areas (e.g., between hunting areas) bowheads have during 

their autumn migration and other use of the Beaufort Sea. 

If seismic operations overlap in time, the zone of seismic exclusion or influence could potentially be quite 

large (see Figures III.F-10 and III.F-11), depending on the number and the relative proximity of the 

surveys. If seismic surveys were unmitigated, or are insufficiently mitigated to reduce impacts to the 

whales themselves, effects could result in avoidance of feeding areas, resting (including nursing) areas, or 

calving areas by large numbers of females with calves or females over a period of many weeks. This can 

be especially important if cow/calf pairs are not able to readily use other similar areas without a costly 

expenditure of energy. Avoidance of critical areas by bowheads, particularly females with calves, 

potentially could lead to population-level consequences. These consequences would be of particular 

concern if such areas included those used for feeding or resting by large numbers of individuals or by 

cow/calf pairs. 

We acknowledge that we are not certain what the potential effects could be on calf survival or growth and 

female reproduction could be if multiple seismic surveys and other noise sources occurred within an area 

that was frequently used for feeding by large numbers of bowhead whales. If seismic surveys were not 

mitigated, or are insufficiently mitigated, effects that are biologically significant could result if seismic 

surveys cause avoidance of feeding areas, resting areas, or calving areas by females with calves, females, or 

aggregations of whales that likely contain reproductive-aged females over a period of many weeks. The 

impact likely would be related to the importance of the food source to the component of the population that 

would have used it, had not the disturbance caused them to avoid or leave the area. Potential impacts to the 

population would be related to the type of individuals that were affected (e.g., juvenile males versus 

females with calves). Activities that cause active avoidance over large distances will have the effect of 

reducing any rest areas (e.g., between hunting areas) bowheads have during their autumn migration and 

other use of the Beaufort Sea. The potential adverse effects of long-term added noise, disturbance, and 

related avoidance of feeding and resting habitat in an extremely long-lived species such as the bowhead 

whale are unknown. Available information does not indicate there were detectable, long-term populationlevel adverse effects on the BCB Seas bowhead from the high level of seismic surveys and exploration 

drilling during the late 1970’s and 1980’s in the Beaufort and Chukchi seas. However, sublethal impacts 

on health (such as reduced hearing or increased stress) could not be detected in this population. Effects on 

reproduction or survival would not be detectable, unless the level of effects was great enough to be detected 

given the error around population estimation. The rates of population increase do not indicate any sublethal 

effects (if they occurred) resulted in a detectable effect on this population’s recovery. 

Seismic surveys during the open-water period have the potential to cause large numbers of bowheads to 

avoid using areas for resting and feeding for long periods of time (days to weeks) while active surveying is 

occurring. Avoidance may persist up to 12-24 hours after the end of seismic operations. We believe that 

potential adverse effects can be reduced thorough careful shaping of the action through the implementation 

of sufficient monitoring coupled with adaptive management (where the mitigations required are dependent 

on what is discovered during monitoring) to focus mitigating measures where most needed. 

In the Beaufort Sea, depending on the restrictions agreed to in a Conflict Avoidance Agreement, it is likely 

that 2D/3D seismic surveys will be conditioned to protect subsistence harvests. For example, seismic 

surveys in the central Beaufort Sea conducted during the open-water season could be limited to areas west 

of Cross Island after September 1 under the provisions of the Conflict Avoidance Agreement between the 

operator and subsistence whalers, and this would greatly reduce impacts on bowhead whales for the period 

of the restriction. Similar agreements between the operator and subsistence whalers are likely to be 

established for any seismic surveys proposed near Kaktovik and Barrow. 

We acknowledge uncertainty about potential effects on bowhead whales in the Chukchi Sea, due to a lack 

of current data about their use of this evaluation area during periods when surveys could be occurring. As 

thousands of bowheads migrate through portions of the Chukchi Sea during the late autumn, careful 

monitoring and mitigation will be necessary to avoid impacting large numbers of individuals. We propose 

monitoring to reduce this uncertainty (see Section IV) coupled with adaptive management that implements 

mitigation packages dependent on what is encountered during monitoring. 

 PEA-139 
Seismic surveys result in an increase in marine vessel activity and, depending on location and season, may 

include icebreakers and supply and other vessels. Whales respond strongly to vessels directly approaching 

them. Avoidance of vessels usually begins when a rapidly approaching vessel is 1-4 km away, with a few 

whales possibly reacting at distances from 5-7 km. Received noise levels as low as 84 dB re 1 μPa or 6 dB 

above ambient may elicit strong avoidance of an approaching vessel at a distance of 4 km. Fleeing from a 

vessel generally stopped within minutes after the vessel passed, but scattering may persist for a longer 

period. 

Icebreaker response distances vary. Predictions from some models indicate that bowhead whales likely 

would respond to the sound of the attending icebreakers at distances of 2-25 km or greater, even much 

greater, with roughly half of the bowhead whales showing avoidance response to an icebreaker underway 

in open water at a range of 2-12 km, when the sound-to-noise ratio is 30 dB, and roughly half of the 

bowhead whales showing avoidance response to an icebreaker pushing ice at a range of 4.6-20 km, when 

the sound-to-noise ratio is 30 dB. Whales appear to exhibit less avoidance behavior with stationary sources 

of relatively constant noise than with moving sound sources. 

In 2006, 2D and 3D seismic survey vessels will be attended by support vessels. If these activities are 

clumped in space and coincident in time and place with large numbers of bowhead whales, large numbers 

of bowheads could be adversely affected. Operations with icebreakers attending could cause a greater zone 

of avoidance than seismic vessels without icebreakers, especially if active ice management is occurring. 

The predicted distances at which bowheads would be expected to avoid icebreakers are highly variable, but 

range up to 95 km, with reaction distances predicted (Richardson et al., 1995b) to commonly be on the 

order of 10-50 km. 

Seismic surveys also may result in increased aircraft traffic, including possible whale-monitoring flights. 

Most bowheads exhibit no obvious response to helicopter overflights at altitudes above 150 m (500 ft). At 

altitudes below 150 m (500 ft), some bowheads probably would dive quickly in response to the aircraft 

noise. Bowheads are not affected much by any aircraft overflights at altitudes above 300 m (984 ft). 

Below this altitude, some changes in whale behavior may occur, depending on the type of plane and the 

responsiveness of the whales present in the vicinity of the aircraft. Fixed-wing aircraft flying at low 

altitude often cause hasty dives. Reactions to circling aircraft sometimes are conspicuous if the aircraft is 

below 300 m (1,000 ft), uncommon at 460 m (1,500 ft), and generally undetectable at 600 m (2,000 ft). 

The effects from such an encounter with either fixed-wing aircraft or helicopters generally are brief, and the 

whales should resume their normal activities within minutes. If numerous flights related to seismic surveys 

occur, depending on the location, bowheads in some areas may be repeatedly exposed to aircraft noise. 

Potential effects could be nearly eliminated by the mitigation in Section IV that specifies that flight altitude 

must be high enough to avoid disturbance. If seismic-survey and aircraft-traffic activities are clumped in 

space and coincident in time and place with large numbers of bowhead whales, large numbers of bowheads 

could be adversely affected. 

Available information does not indicate any long-term population-level adverse effects on the BCB Seas 

bowhead from the high level of seismic surveys and exploration drilling during the 1980’s in the Beaufort 

and Chukchi seas. However, sublethal impacts on health (such as reduced hearing or increased stress) or 

low-level effects on reproduction and survival were not scientifically detectable in this population. Data 

are insufficient to determine the extent of behavioral, including habitat use, effects that may have occurred 

during this time period. Data do indicate that this population continued to recover during the 1980’s but are 

insufficient to determine if the rate of recovery was affected. There has been no documented evidence that 

noise from previous OCS operations has served as a barrier sufficient to disrupt the overall migration. 

Because bowheads respond behaviorally to loud noise, they are less likely to suffer hearing loss from 

increased noise. However, bowheads are more tolerant of noise when feeding, and future work is needed to 

determine potential effects on hearing due to long periods over many years of exposure to loud noise at 

distances tolerated in feeding areas. Similarly, concern needs to be given to other potential physiological 

effects of loud noise on bowheads, including the potential for increased noise to cause physiological stress 

responses. 

Overall, impacts from seismic surveys under the Proposed Action could result in some exclusion or 

avoidance of bowhead whales from feeding areas and disruption of important biological behaviors. The 

 PEA-140 
MMS believes that the Proposed Action alternatives can be performed in an environmentally sound manner 

without generating significant impacts (see Sec. II). Additional resource-specific mitigation measures have 

been identified through the PEA analyses (see Sec. IV). 

III.F.3.f(15) Potential Effects of Seismic Survey-Related Noise and Disturbance on Fin and Humpback 

Whales. We have no information that indicates that fin or humpback whales are known to inhabit the 

Beaufort Sea or adjacent areas. Thus, noise-producing oil and gas activities within the Beaufort Sea are not 

likely to affect this species. Neither fin whales nor humpback whales are known to typically inhabit the 

Chukchi Sea Planning Area. However, both species are known to inhabit the southwestern portions of the 

Chukchi Sea, in waters adjacent to the coast of Chukotka. They also inhabit the Bering Strait and northerly 

portions of the Bering Sea. They could be disturbed by an increase in oil- and gas-related shipping through 

the Bering Strait that could result from increased activities in the two Arctic planning areas. Such effects 

should be temporary and minor. Based on available information, we conclude it is unlikely that there will 

be adverse effects on either fin whales or humpback whales from noise-producing activities in the Beaufort 

or Chukchi seas evaluation areas. We acknowledge that there no current data are available that are 

sufficient on which to determine current use of the Chukchi Sea Program Area (except that area directly 

north of Barrow), or adjacent areas. 

Based on available information, it is unlikely that there would be any major effect of noise and disturbance 

associated with oil and gas activities in the Chukchi Sea Planning Area on humpback whales or fin whales. 

Our summary of information about the current and historic distributions of fin whales and humpback 

whales indicate that these species are not likely to be exposed to potential noise and disturbance associated 

with many of the actions that could occur within the Chukchi Sea or the Beaufort Sea Planning Areas. 

Because we must presume, for the purposes of analyses, that seismic surveys could occur anywhere 

throughout the Chukchi Sea evaluation area, because we have incomplete knowledge of potential sound 

propagation in various locations and under specific conditions in the Chukchi Sea, and based on results 

from other studies in which seismic sound has been detectable hundreds and even thousands of kilometers 

from the source, we cannot rule out that humpback or fin whales feeding north of the Chukchi Peninsula 

could hear noise from seismic surveys associated with exploration, especially sounds from the 2D/3D 

seismic surveys that were occurring in the Chukchi Sea evaluation area. Impacts of such noise detection, if 

such detection occurs at all and causes any response, are most likely to be short term and related to minor 

behavioral changes, if any, and to be of negligible impact to the population. The most likely potential 

effect, if the humpback or fin whales hear some components of the seismic noise, would be some increased 

attentiveness to the noise, with a potential for slight modification of their attentiveness to other sounds and 

possibly changes in their vocalizations. 

Fin whales and humpback whales also might be exposed to the seismic-survey vessels or to the support 

vessels as the boats transit to the Chukchi Sea in June and return as ice conditions dictate in the autumn. 

As noted, survey data indicate that humpback whales leave the most southern part of the Chukchi Sea, the 

northern part of the Gulf of Anadyr prior to the start of ice formation (Mel’nikov, 2000). As vessels may 

be heading south to avoid the same ice, these vessels could overlap in time and space with the whales as 

both head southward. All vessels are required to comply with law that forbids a person subject to the 

jurisdiction of the U.S. to approach, by any means, within 100 yd (91.4 m) of a humpback whale in any 

waters within 200 nmi of Alaska. Vessels (with some exemptions) transiting near humpbacks also are 

required to adhere to a “slow, safe speed” requirement to prevent disturbance that could adversely affect 

humpbacks. 

For the reasons given above, we conclude it is unlikely there would be adverse effects from noise and 

disturbance associated with oil and gas seismic-survey activities in the Chukchi Sea evaluation area on fin 

or humpback whales because of the distance they are expected to be from such activities. We acknowledge 

that recent data confirming the lack of use of these two species in areas near the Chukchi Sea Planning 

Area are lacking. If humpback whales and fin whales were present, available data indicate that humpback 

whales are likely to be more responsive to seismic-survey noise than fin whales, and behavior disturbance 

could occur as with bowhead whales. We reiterate that available information indicates neither of these is 

likely to be present within the area where seismic surveys may occur. 

 PEA-141 
III.F.3.g. Mitigation Measures for Bowhead Whales. As pointed out by the Federal Caucus Finding of 

the Marine Mammal Commission Sound Advisory Panel (Marine Mammal Commission, 2006:B-12): 

“Improving mitigation depends upon the ability to understand the effect that is being mitigated...Efforts to 

monitor the effectiveness of these” mitigation “techniques and develop a better system are warranted.” 

To achieve effective mitigation of potential effects of seismic surveys on bowhead whales, and to avoid the 

potential for adverse effects on bowhead calves and reproductive-aged females, effective monitoring and 

adaptive management would be required. Effective preseismic-surveying monitoring surveys would be 

necessary in both the Beaufort and the Chukchi Sea to reduce uncertainty about how many and what type 

of bowheads might be exposed to noise and disturbance associated with seismic surveys and to form a basis 

for deciding whether ramp up could be initiated and what decibel-level exclusion zone is warranted. This 

is particularly the case in the Chukchi Sea, where recent data are insufficient to determine current bowheadhabitat use sufficient to evaluate potential impacts. Thus, pre-seismic–survey monitoring needs to be 

undertaken by the operator to determine the distribution and abundance and type of bowhead whales 

present in the areas in which the seismic survey will occur. Such monitoring surveys would be conducted 

using protocol approved by NMFS and would determine whether seismic operations can be initiated and 

the size of the exclusion zone to be implemented.. 

Section IV describes measures to further reduce potential adverse impacts to bowhead whales. Given the 

lack of scientific certainty in some areas, MMS adopted a cautious approach in assessing potential impacts 

to bowhead whale cow/calf pairs and large aggregations of feeding whales. 

III.F.3.h. Impact Assessment of Alternatives. The following analysis provides a comparison of the 

relative levels of protection to threatened and endangered marine mammals found in the Proposed Action 

area under the various alternatives, using the significance criteria for endangered whales defined in Section 

III.E.2. 

III.F.3.h(1) Alternative 1. The no-action alternative (no seismic survey permits issued for geophysical 

exploration activities) would not expose marine mammals in the project area to noise associated with 

seismic surveys and their associated support vessels (air and sea).. 

III.F.3.h(2) Alternatives 3 through 6. Alternatives 3 through 6 are similar but have varying levels of 

protection for marine mammals. This variation in protection primarily is in the noise level set as the shutdown criteria and monitoring that is required to effectively monitor that noise-level radii, or shutdown/exclusion zone (Alternative 3, 120-dB exclusion zone; Alternative 4, 160-dB exclusion zone; 

Alternative 5, 120/160-dB exclusion zone; Alternative 6, 180/190-dB exclusion zone).

While all alternatives other than the No-Action Alternative meet the objectives of this environmental 

assessment, they also potentially could adversely affect bowhead whales and other marine mammals, 

principally through incidental harassment due to exposure to seismic survey noise. Possible harassment 

likely would be most pronounced if large feeding aggregations of whales, or cow/calf pairs of bowhead 

whales, are affected. Alternatives 3 through 6, especially as mitigated, have the potential for causing 

adverse but not significant impacts. Further protection from potential adverse effects can be provided by 

the additional mitigation measures developed in this PEA. 

Alternatives 3 through 6 would prohibit seismic surveys around bowheads in the spring lead system and 

thereby reduce the potential for adverse effects of seismic surveys on bowhead calving, cow/calf pairs, and 

newborn calves. The effect of seismic surveys on these components of the population is very uncertain, 

and avoidance of their exposure is the most effective way to reduce the potential for an adverse effect on 

these bowheads. Even at a 120-dB isopleth shut-down zone (included in Alternatives 3 and 5), bowhead 

whales might still detect seismic survey airgun sounds, icebreaker sound, or vessels associated with seismic 

surveys. 

Variability in the size and configuration of the airgun arrays, water depth, and bottom properties all can 

influence this noise-level radii, which is expected to vary from one location to another and between 

different seismic operations. Therefore, field verification is included as a mitigation measure to verify the 

 PEA-142 
actual noise-level radii. As noted in the non-endangered marine mammal section (III.F.4), these shut-down 

or safety zones may be as large as 30 km for the 120-dB zones and as small as 100 m for the 190-dB zones, 

depending on the size and energy output of the airgun array and environmental conditions. It is likely that 

monitoring will be required using one or more of these: aerial surveys; passive acoustic monitoring; and 

boat-based surveys. If these methods of monitoring are not effective, then additional mitigation measures 

may be set in place (i.e., adaptive management schemes where specific areas of higher marine mammal 

concentrations are avoided on a temporal or spatial basis). For example, it may be necessary to exclude 

seismic surveys from areas that historical data indicate could have high use during the open-water season 

by bowhead whales, unless survey data or monitoring can demonstrate that bowhead females and cow/calf 

pairs will not be excluded from areas of potentially high importance to them. 

Alternatives 3 through 6 provide monitoring requirements meant for observers to visually monitor the 

exclusion zone, regardless of size, and be able to call for a shut down if marine mammals enter the 

exclusion zone. The ability of observers to effectively monitor the exclusion zone, and be able to call for a 

shut down if bowheads enter the zone, is critical to the success of the protective measures described in 

Alternatives 3 through 6, although it is generally not possible to observe all bowheads within the exclusion 

zone, especially during foggy weather or at night. Additional monitoring techniques, such as aerial 

surveys, vessel-based systems, or passive acoustics, could enhance the ability to detect bowhead whales 

and other marine mammals in larger exclusion zones. 

Evidence shows that bowhead whales and other cetaceans can react behaviorally in the presence of aircraft. 

The mitigations imposed under Alternatives 3 through 6 all would require that aircraft be flown no lower 

than 1,000 ft, a level that limits the potential for reactions from marine mammals. Therefore, the use of 

aerial overflights in monitoring would not be expected to add additional impacts to bowhead whales. The 

same is true for passive acoustic monitoring where observers simply “listen” for evidence of whale noise. 

Vessel-based monitoring may impose a degree of additional disturbance, but it would be considered less 

than what would occur for seismic activity should whales not be monitored but present in the exclusion 

zone. 

We reiterate the assessments made in the non-threatened and endangered marine mammal section (III.F.4). 

Each exclusion zone in Alternatives 3 through 6 would require boat-based visual monitoring (i.e., all 

observers are scanning areas from the vessel as far as visually possible with appropriate equipment). The 

additional monitoring techniques (e.g. aerial or vessel-based surveys, acoustic monitoring) that may be 

necessary for Alternatives 3 and 5 could be costly to implement because the larger exclusion zone 

associated with the 120-dB isopleth, in theory, would provide a much larger and more difficult area to 

monitor then the smaller exclusion zones (160-dB isopleth and 180/190-dB isopleth). Smaller exclusion 

zones are less effective in limiting impacts to cetaceans than larger exclusion zones because larger 

exclusion zones associated with Alternatives 3 and 5 would by definition require further distance of 

operating seismic survey vessels from cetaceans than Alternatives 4 and 6. Additional mitigation measures 

would be set in place (i.e., adaptive management schemes where specific areas of higher marine mammal 

concentrations are avoided on a temporal or spatial basis) should monitoring measures prove ineffective. 

Therefore, the varying degrees of impact among the alternatives, as discussed in the paragraphs above, 

remains the same with the greatest to least level of protection from behavioral disturbance being 

Alternatives 3, 5, 4, and 6 respectively. 

III.F.4. Other Marine Mammals. There are eleven species not listed as endangered or threatened 

by the ESA that occur in or near the areas that may be surveyed in the Beaufort and Chukchi seas. They 

are: 

Pinnipeds 

Ringed seal (Phoca hispida) 

Spotted seal (Phoca largha) 

Ribbon seal (Phoca fasciata) 

Bearded seal (Erignathus barbatus) 

Pacific walrus (Odobenus rosmarus divergens) 

 PEA-143 
Cetaceans 

Beluga whale (Delphinapterus leucas)

Killer whale (Orcinus orca)

Minke whale (Balaenoptera acutorostrata)

Harbor porpoise (Phocoena phocoena)

Gray whale (Eschrichtius robusta)

Marine Fissipeds 

Polar bear (Ursus maritimus) 

There are no State-listed species of special concern (marine mammals) within the Proposed Action area. 

Detailed information on marine mammal harvest and subsistence issues can be found later in this document 

under Section III.G. (Community Setting). 

III.F.4.a. Affected Species and their Habitat. 

III.F.4.a(1) Pinnipeds. 

III.F.4.a(1)(a) Ringed Seal. Ringed seals have a circumpolar distribution from approximately 35° N. 

latitude to the North Pole, and occur in all seas of the Arctic Ocean (King, 1983). They are closely 

associated with ice, and in summer often occur along the receding ice edges or farther north in the pack ice. 

Ringed seals seem to prefer large icefloes greater than (>) 48 m in diameter, and they are often found in the 

interior pack ice where sea ice concentrations exceed 90% (Simpkins et al., 2003). They are found 

throughout the Beaufort, Chukchi, and Bering seas (Angliss and Outlaw, 2005) and are the most common 

and widespread seal species in the area. 

No reliable estimate currently is available for the size of the Alaska ringed seal stock (Angliss and Outlaw, 

2005), although past estimates ranged from 1.0 million to 3.6 million (Frost et al., 1988). Recent work by 

Bengtson et al. (2005) reported an estimated abundance of as many as 252, 488 ringed seals in the eastern 

Chukchi Sea. Frost et al. (2002) reported that population trend analyses in the central Beaufort Sea 

suggested a substantial decline of 31% in observed ringed seal densities from 1980-1987 to 1996-1999. 

This apparent decline may have been due to a difference in the timing of surveys rather than an actual 

decline in abundance (Frost et al., 2002). Ringed seals are not listed as “depleted” under the MMPA. The 

Alaska stock of ringed seals is not classified as a strategic stock by the NMFS. 

In early summer, the highest densities of ringed seals in the Chukchi Sea are found in nearshore fast and 

pack ice (Bengston et al., 2005). This also appears to be true in the Beaufort Sea, based on incidental 

sightings during aerials surveys for bowhead whales (Monnett and Treacy, 2005). During summer, ringed 

seals are found dispersed throughout open-water areas, although in some regions they move into coastal 

areas (Smith, 1987; Harwood and Stirling, 1992). 

Ringed seals give birth from mid-March through April to a single pup, which they nurse in the lair for 5-8 

weeks (Hammil et al., 1991; Lydersen and Hammill, 1993). Pupping occurs in lairs constructed on either 

landfast or drifting pack ice. Mating occurs shortly after pupping (~ 4 weeks), and the female delays 

implantation of the embryo until later in the summer (July-August). Ringed seals feed on a variety of fish 

and invertebrates. Diet depends on the prey availability, depth of water, and distance from shore. In 

Alaskan waters, the primary prey of ringed seals is arctic cod, saffron cod, shrimps, amphipods, and 

euphausiids (Kelly, 1988; Reeves, Stewart, and Leatherwood, 1992).

Ringed seals are an important subsistence species for Alaskan Native hunters. The number of seals taken 

annually varies considerably between years due to ice and wind conditions, which impact hunter access to 

seals. The State of Alaska, Department of Fish and Game (ADF&G) maintains a subsistence harvest 

database and, as of August 2000, the mean estimate of ringed seals taken annually is 9,567 (Angliss and 

Outlaw, 2005). 

 PEA-144 
II.F.4.a(1)(b) Spotted Seal. Spotted seals are distributed along the continental shelf of the Beaufort, 

Chukchi, Bering, and Okhotsk seas, and south to the northern Yellow Sea and western Sea of Japan 

(Shaughnessy and Fay, 1977). They are common in the coastal Alaskan waters in ice-free seasons. They 

migrate south from the Chukchi Sea and into the Bering Sea in October-November (Lowry et al., 1998). 

Spotted seals overwinter in the Bering Sea and inhabit the southern margin of the ice during spring, moving 

to coastal habitats after the retreat of the sea ice (Shaughnessy and Fay, 1977; Simpkins et al., 2003). In 

summer and fall, spotted seals regularly use coastal haulouts, and may be found as far north 72° N. latitude 

(Shaughnessy and Fay, 1977). Spotted seals are closely related to, and often mistaken for, Pacific harbor 

seals (Phoca vitulina richardsi). The two species are often seen together and are partially sympatric in the 

southern Bering Sea (Quakenbush, 1988). 

No reliable estimate for the size of the Alaska spotted seal stock currently is available (Angliss and Outlaw, 

2005). An early estimate of the size of the world population of spotted seals was 370,000-420,000, and the 

size of the Bering Sea population, including animals in Russian waters, was estimated to be 200,000-

250,000 animals (Bigg, 1981). Using a correction factor, the ADF&G corrected 1992 survey results 

producing a rough estimate of 59,214 animals (Angliss and Outlaw, 2005) for western Alaska and the 

Bering Sea. In total, there are probably only a few dozen spotted seals along the coast of the central 

Beaufort Sea during the summer and early fall (Richardson, 2000). Spotted seals are not listed as 

“depleted” under the MMPA. The Alaska stock of spotted seals is not classified by NMFS as a strategic 

stock. 

During spring when pupping, breeding, and molting occur, spotted seals inhabit the southern margin of the 

sea ice in the Bering Sea (Quakenbush, 1988; Rugh, Shelden, and Withrow, 1997). Of eight known 

breeding areas, three occur in the Bering Sea (Angliss and Outlaw, 2005). Pupping occurs on ice in AprilMay, and pups are weaned within 3-4 weeks. Adult spotted seals often are seen on the ice in female-pup or 

male-female pairs, or in male-female-pup triads. Mating occurs around the time the pups are weaned, and 

mating pairs are monogamous for the breeding season. During the summer, spotted seals are found 

primarily in the Bering and Chukchi seas, but some range into the Beaufort Sea (Rugh, Shelden, and 

Withrow, 1997; Lowry et al., 1998) from July until September. At this time of year, spotted seals haul out 

on land part of the time but also spend extended periods at sea. The seals are commonly seen in bays, 

lagoons, and estuaries, but they also range far offshore to 72° N. latitude. Spotted seals are rarely seen on 

the pack ice during the summer, except when the ice is very near shore. Principal foods of adult spotted 

seals are schooling fishes, although the total array of foods is quite varied. In the Arctic, their diet is 

similar to that of ringed seals, including a variety of fishes such as arctic and saffron cod and also shrimp 

and euphausiids (Kato, 1982; Quakenbush, 1988; Reeves, Stewart, and Leatherwood, 1992). Within their 

geographic range, spotted seals are known to eat sand lance, sculpins, flatfishes, and cephalapods (mainly 

octopus). The juvenile diet is primarily crustaceans (shrimp). 

Spotted seals are an important subsistence species for Alaskan Native hunters, primarily in the Bering Strait 

and Yukon-Kuskokwim regions (Lowry, 1984). The number of seals taken annually varies considerably 

between years due to ice and wind conditions, which impact hunter access to seals. Between 1966 and 

1976, an average of about 2,400 spotted seals were taken annually (Lowry, 1984). The ADF&G maintains 

a subsistence harvest database that indicates that at least 5,265 spotted seals are taken annually for 

subsistence use (Angliss and Outlaw, 2005). 

II.F.4.a(1)(c) Ribbon Seal. Ribbon seals inhabit the North Pacific Ocean and the adjacent fringes of the 

Arctic Ocean. In Alaska, they range northward from Bristol Bay in the Bering Sea and into the Chukchi 

and western Beaufort seas. They are found in the open sea, on pack ice, and rarely on shorefast ice (Kelly, 

1988). As the ice recedes in May to mid-July, they move farther north in the Bering Sea, hauling out on the 

receding ice edge and remnant ice (Burns, Shapiro, and Fay, 1981). Seal distribution throughout the rest of 

the year is largely unknown; however, recent information suggests that many ribbon seals migrate into the 

Chukchi Sea for the summer months (Kelly, 1988). 

No reliable estimate for the size of the Alaska ribbon seal stock currently is available (Angliss and Outlaw, 

2005). Burns (1981) estimated the Bering Sea population at 90,000-100,000. Ribbon seals are not listed as 

 PEA-145 
“depleted” under the MMPA. The Alaska stock of spotted seals is not classified by NMFS as a strategic 

stock. 

Females give birth anytime from early April to about mid-May, with pupping occurring on pack ice. 

Nursing lasts from 3-4 weeks, during which time a pup’s weight more than doubles. Mating occurs about 

the time pups are weaned. After weaning, pups spend a great deal of time on the ice, achieving proficiency 

at diving and feeding. Ribbon seals dive as deep as 200 m in search of food. They eat a variety of different 

foods, but their main prey is fish; they also are known to consume eelpouts, capelin, pricklebacks, arctic 

cod, saffron cod, herring, and sand lance. Foods other than fishes include cephalopods (primarily squids), 

shrimps, mysids, and crabs. 

Ribbon seals are an occasionally harvested by Alaskan Native hunters though subsistence harvest levels are 

low. The number of seals taken annually varies considerably between years due to ice and wind conditions, 

which impact hunter access to seals. The ADF&G maintains a subsistence harvest database, and the mean 

estimate of ribbon seals taken annually is 193 (Angliss and Outlaw, 2005). 

Bearded Seal. Bearded seals have a circumpolar distribution ranging from the Arctic Ocean down into the 

western Pacific (Burns, 1981). In Alaskan waters, bearded seals occur over the continental shelves of the 

Bering, Chukchi, and Beaufort seas (Burns, 1981). In some areas, bearded seals are associated with the ice 

year-round; however, they usually move shoreward into open-water areas when pack ice retreats. During 

the open-water period, bearded seals occur mainly in relatively shallow areas, preferring areas no deeper 

than 200 m (Angliss and Outlaw, 2005). 

No reliable estimate for the size of the Alaska bearded seal stock currently is available (Angliss and 

Outlaw, 2005). Bengtson et al. (2005) conducted surveys in the eastern Chukchi Sea but could not estimate 

abundance from their data. Early estimates of the Bering-Chukchi seas population range from 250,000-

300,000 (Burns, 1981). Bearded seals are not listed as “depleted” under the MMPA. The Alaska stock of 

bearded seals is not classified by NMFS as a strategic stock. 

Seasonal movements of bearded seals are directly related to the advance and retreat of sea ice and to water 

depth (Kelly, 1988). During winter, most bearded seals in Alaskan waters are found in the Bering Sea. 

From mid-April to June, as the ice recedes, some of the bearded seals that overwintered in the Bering Sea 

migrate northward through the Bering Strait. During the summer, the most favorable bearded seal habitat 

is found in the central and northern Chukchi Sea, where they are found near the widely fragmented margin 

of the pack ice; they are also found in nearshore areas of the central and western Beaufort Sea during 

summer. Females pup in April-May, bearing a single pup. Breeding occurs within a few weeks after the 

pup is weaned, and implantation is delayed until July. Bearded seals are predominantly benthic feeders 

(Burns, 1981), feeding on a variety of invertebrates (crabs, shrimp, clams, and snails) and other food 

organisms, including arctic and saffron cod, flounders, sculpins, and octopuses (Kelly, 1988; Reeves, 

Stewart, and Leatherwood, 1992). Bearded seals also feed on ice-associated organisms when they are 

present, allowing them to live in areas considerably more than 200 m deep. 

Bearded seals are an important subsistence species for Alaskan Native hunters. The number of seals taken 

annually varies considerably between years due to ice and wind conditions, which impact hunter access to 

seals. The ADF&G maintains a database, and the mean estimate of bearded seals taken annually is 6,788 

(Angliss and outlaw, 2005). 

Pacific Walrus. Pacific walrus range throughout the shallow continental shelf waters of the Bering and 

Chukchi seas, where their distribution is closely linked with the seasonal distribution of the pack ice. 

Walrus are extremely social and gregarious animals, and spend approximately one-third of their time 

hauled out onto land or ice, usually in close physical contact with one another. Walrus rely on sea ice as a 

substrate for resting and giving birth (Angliss and Outlaw, 2005) and generally require ice thicknesses of 

50 cm or more to support their weight (Garlich-Miller, 2006, pers. commun.). During the summer months 

most of the population moves into the Chukchi Sea; however, large congregations of primarily adult males 

use coastal haulouts in Bristol Bay and Gulf of Anadyr (Angliss and Outlaw, 2005). Concentrations in 

summer tend to be in areas of unconsolidated pack ice within 100 km of the leading edge of the pack ice. 

 PEA-146 
Walrus generally prefer waters <200 m deep along the pack ice margin where ice concentrations are <80% 

(Fay 1982; Fay and Burns, 1988). The juxtaposition of broken ice over relatively shallow continental shelf 

waters is important for feeding, particularly for females with dependent young that may not be capable of 

deep diving or long term exposure to the frigid water. When suitable pack ice is not available, walruses 

will haul out to rest on land, preferring sites sheltered from wind and surf. Traditional haulout sites in the 

eastern Chukchi Sea include Cape Thompson, Cape Lisburne, and Icy Cape. In recent years, Cape 

Lisburne has seen regular walrus use in the late summer (Garlich-Miller, 2006, pers. commun.). 

Walrus are long lived animals with low rates of reproduction. Females reach sexual maturity at 4-9 years 

of age, and give birth to one calf every two or more years. Though males become fertile at 5-7 years of 

age, they do not reach full competitive maturity until age 15-16. Some walrus may live to age 35-40 and 

remain fertile until relatively late in life. No reliable estimate for the size of the Alaska Pacific walrus 

stock currently is available (Angliss and Outlaw, 2005). Estimates of the Pacific walrus population suggest 

a minimum of 200,000 animals were necessary to withstand the levels of commercial harvest which 

occurred in the 18th and 19th centuries (Fay, 1982). The population size has never been known with 

certainty, however. Pacific walrus are not listed as “depleted” under the MMPA. The Alaska stock of 

Pacific walrus is not classified by NMFS as a strategic stock. 

Walruses are migratory, moving south with the advancing ice in autumn and north as the ice recedes in 

spring (Fay, 1981). In the winter, pacific walrus inhabit the pack ice of the Bering Sea. Breeding occurs 

between January and March, and implantation is delayed until June-July. Calving occurs in April-May on 

sea ice, and calves are not weaned for two years or more (Fay, 1982). By May, as the pack ice loosens, 

they move northward into the Chukchi Sea and are rarely found east of Barrow, and only a few are seen 

farther east in the Beaufort Sea (e.g., Harwood et al., 2005). Walruses observed in the Beaufort Sea 

typically have been lone individuals. By July, large groups of up to several thousand walruses can be 

found along the edge of the pack ice between Icy Cape and Point Barrow. By September, the edge of the 

pack ice generally retreats to about 71 °N, although it may retreat as far as 76 °N in some years. In October 

as the pack ice develops, large herds begin moving back down to the Bering Sea. 

Walrus are benthic feeders, preferring areas water depth <100 m (Fay, 1982). In a recent study, 98% of 

satellite locations of tagged walruses in Bristol Bay were in water depths of 60 m or less (Jay and Hills, 

2005). They most commonly feed on bivalve mollusks (clams), but they also will feed on other 

invertebrates (e.g., crabs, worms). Some walrus have been reported to prey on marine birds and small 

seals. 

Pacific walrus are an important subsistence species for Alaskan Native hunters. The number of walrus 

taken annually has varied over the years, with recent harvest levels much lower than historic highs. Based 

on harvest data from Alaska and Chukotka in the years 1996-2000, harvest mortality levels are estimated at 

5,789 animals per year (Angliss and Outlaw, 2005). 

III.F.4.a(2) Cetaceans. 

Beluga Whale. Beluga whales are found throughout the arctic and subarctic waters of the Northern 

Hemisphere. They inhabit seasonally ice-covered waters and are closely associated with open leads and 

polynyas in ice-covered regions (Hazard, 1988). In summer months, they migrate to warmer coastal 

estuaries, bays, and rivers (Finley, 1982). In Alaska there are five recognized stocks: (1) Eastern Chukchi 

Sea; (2) Beaufort Sea; (3) Cook Inlet; (4) Bristol Bay; and (5) Eastern Bering Sea (O’Corry-Crowe et al., 

1997). Within the Proposed Action area, only the Beaufort Sea stock and eastern Chukchi Sea stocks are 

present. 

The NMFS has set the minimum population estimate for the Beaufort Sea beluga whale stock at 32,453 

and the eastern Chukchi Sea stock at 3,710 (Angliss and Outlaw, 2005). Of the five beluga whale stocks, 

only the Cook Inlet stock is listed as “depleted” under the MMPA (Angliss and Outlaw, 2005). Neither the 

Beaufort Sea nor the eastern Chukchi Sea stocks are listed as “depleted” nor classified as a strategic stock 

under the MMPA. 

 PEA-147 
Pod structure in beluga groups appears to be along matrilineal lines, with males forming separate 

aggregations. Small groups often are observed traveling or resting together. Females calve in the MayJuly, when herds are in their summer areas. Calves typically are weaned at 2 years of age. Mating occurs 

in the early spring (March-April). 

Beluga whales of both stocks winter in the Bering Sea and summer in the Beaufort and Chukchi Seas, 

migrating around western and northern Alaska (Angliss and Outlaw, 2005). The majority of belugas in the 

Beaufort stock migrate into the Beaufort Sea in April or May, although some whales may pass Point 

Barrow as early as late March and as late as July (Braham et al., 1984; Ljungblad et al., 1984; Richardson 

et al., 1995a). Most belugas move into shallow coastal or estuarine waters during at least a portion of the 

summer (Caron and Smith, 1990; Frost and Lowry, 1990). These areas of summer concentration are 

consistent from year to year. Eastern Chukchi belugas move into coastal areas along Kotzebue Sound and 

Kasegaluk Lagoon in late June and remain there until mid to late July (Suydam et al., 2001). Subsistence 

hunting occurs on this stock during their time in these waters. Research suggests these areas are likely used 

for molting and some of the largest gravel beds occur there (Frost, Lowry, and Carroll, 1993). 

After leaving these coastal areas, it is believed the animals move northeastward and spend the remainder of 

the summer in the northern Chukchi and western Beaufort seas. Recent research suggests that belugas are 

not necessarily limited by heavy ice cover during this time and are able to travel great distances in short 

time periods. Whales may remain in pods for weeks or months or may move as much as 700 km apart and 

converge again later (Suydam et al., 1993). During the late summer and autumn, most belugas migrate far 

offshore near the pack ice front (Frost et al., 1988; Hazard, 1988; Clarke, Moore, and Johnson, 1993; 

Miller, Elliott, and Richardson, 1998). Moore (2000) and Moore et al. (2000) suggest that beluga whales 

select deeper slope water independent of ice cover. The main fall migration corridor of beluga whales is 

~100+ km north of the coast. During that time, belugas can be found in large groups exceeding 500 

animals (Lowry et al., 1993). In the eastern Beaufort Sea, the westward fall migration occurs in mid to late 

September and October (Treacy, 1994; Richard et al., 1997, 1998). Based on recent telemetry studies on 

eastern Chukchi belugas, it is likely that members from both stocks occur in similar places and at similar 

times during the fall migration although the significance of this is unknown (Suydam et al., 1993). 

Winter food habits of belugas are largely unknown; however, during the summer they eat a wide variety of 

prey (USDOI, MMS, 2005). In summer they feed on a variety of schooling and anadromous fishes that are 

sequentially abundant in coastal zones. Principal species eaten include herring, capelin, smelt, arctic and 

saffron cods, salmon, flatfishes, and sculpins. Octopus, squid, shrimps, crabs, and clams are eaten 

occasionally. Most feeding is done over the continental shelf and in nearshore estuaries and river mouths. 

In the shallow waters of Alaska, most feeding dives are probably to depths of 20-100 ft (6-30 m) and last 2-

5 minutes. 

Beluga whales from both stocks are an important subsistence resource for Alaskan Native hunters. For the 

eastern Chukchi Sea stock, annual subsistence take averaged 65 animals from 1999-2003. Annual 

subsistence take for the Beaufort Sea stock averaged 53 animals for the same period (Angliss and Outlaw, 

2005). Beluga whales from the eastern Chukchi Sea stock are an important subsistence resource for 

residents of the village of Point Lay, adjacent to Kasegaluk Lagoon, and other villages in northwest Alaska 

(Suydam et al., 2001). 

Killer Whale. Killer whales are found in all oceans and seas of the world and are common in temperate 

waters; however, they also frequent tropical and polar waters. The greatest abundance is thought to occur 

within 800 km of major continents (Mitchell, 1975). Along the west coast of North America, killer whales 

occur along the entire Alaskan coast (Braham and Dahlheim, 1982). This includes the Chukchi Sea, into 

the Bering Sea, along the Aleutian Islands, the Gulf of Alaska, and into southeast Alaska. 

Killer whales in Alaska are composed of two stocks: the eastern north Pacific northern resident stock and 

the eastern north Pacific transient stock. Population abundance for the transient stock includes animals 

from British Columbia (trans-boundary) and is estimated at a minimum of 346 individuals. The resident 

stock also is a trans-boundary stock, including animals from British Columbia. Population estimates for 

this stock are estimated at a minimum of 723 individuals. Only the AT1 pod of killer whales, occurring 

 PEA-148 
primarily in Prince William Sound and the Kenai Fjords region, is listed as “depleted” under the MMPA 

and designated by NMFS as a strategic stock (Angliss and Outlaw, 2005). Killer whales occurring in the 

Beaufort and Chukchi are not listed as “depleted” under the MMPA nor classified by NMFS as a strategic 

stock. 

Killer whales travel through the Bering Strait in the spring as the pack ice retreats and can be found in the 

Beaufort and Chukchi seas until the fall, when the ice advances. Killer whales travel in close-knit 

matrilineal groups and appear to follow the distribution of their prey. Calving occurs in the late fall to 

spring. Killer whales are opportunistic feeders and will prey on a variety of prey items including marine 

mammals, fish, and squid. 

Killer whales are not harvested as a subsistence species by Alaskan Native hunters. 

Minke Whale. In the North Pacific, minke whales range into the Bering and Chukchi seas south to the 

equator (Leatherwood et al., 1982). Minke whales are not considered to range into the Beaufort Sea. 

There are two stocks that occur within U.S. waters: (1) Alaska stock and (2) California/Washington/Oregon 

stock (Angliss and Outlaw, 2005). In Alaska, minke whales are believed to be migratory in contrast to 

whales from the Washington/Oregon/California stock that establish inland coastal home ranges (Dorsey et 

al., 1990). 

There are no reliable estimates for the Alaska stock of minke whales. A provisional estimate was made for 

the Bering Sea of 810 individuals; however, this is not used for the Alaska stock because the entire stock’s 

range was not surveyed. Minke whales are not listed as “depleted” under the MMPA nor classified by 

NMFS as a strategic stock. 

Minke whales are known to penetrate loose ice in the summer. Aerial surveys suggest that minke whales 

are associated with the 100-m contour in upper slope waters (Moore et al., 2000). They are either solitary 

or found in small groups, but they can occur in large aggregations associated with concentrations of prey in 

the higher latitudes. Calving occurs during the winter months at the lower latitudes. Minke whales feed on 

both fish (e.g., herring, sandlance) as well as on invertebrates (e.g., euphasiids, copepods). 

Minke whales are rarely used as a subsistence species by Alaskan Natives, but some takes have occurred. 

Annual subsistence takes average zero in recent history (Angliss and Outlaw, 2005). 

Harbor Porpoise. The harbor porpoise inhabits shallow, coastal areas in temperate, subarctic, and arctic 

waters of the Northern Hemisphere (Read, 1999). In the north Pacific, harbor porpoises range from Point 

Barrow, Alaska to Point Conception, California (Gaskin, 1984). In Alaska, three separate stocks have been 

recommended, though there is insufficient biological data to support the designation at this time. The 

southeast Alaska stock, the Bering Sea stock, and the Gulf of Alaska stock have been identified based on 

arbitrarily set geographic boundaries (Angliss and Outlaw, 2005). The Bering Sea stock is the only stock 

expected to be present in the action area. 

Minimum population estimate for the Bering Sea stock of harbor porpoises is 39,328 (Angliss and Outlaw, 

2005). The Bering Sea stock of harbor porpoise is not listed as “depleted” under the MMPA nor classified 

by NMFS as a strategic stock. 

Harbor porpoises occur mainly in shelf areas (Read, 1999), diving to depths of at least 220 m and staying 

submerged for more than 5 minutes (Harwood and Wilson, 2001). Harbor porpoises typically occur in 

small groups of only a few individuals (Read, 1999); however, they can be observed in larger aggregations 

during feeding or migration. Calving occurs during spring-early summer, and calves are weaned within a 

year. Harbor porpoises feed on a variety of small, schooling fish and cephalopods (Read, 1999). 

Harbor porpoises are not taken by Alaskan Native hunters for subsistence. 

Gray Whale. Gray whales formerly inhabited both the North Atlantic and North Pacific oceans; however, 

they are believed to have become extinct in the Atlantic by the early 1700’s. There are two stocks 

 PEA-149 
recognized in the North Pacific: the eastern north Pacific stock, which lives along the west coast of North 

America, and the western north Pacific stock, which lives along the coast of eastern Asia (Angliss and 

Lodge, 2005). 

The latest abundance estimate for the eastern north Pacific stock is 18,178 individuals (Rugh et al. in press, 

as cited in Angliss and Outlaw, 2005). NMFS has provided a minimum population estimate of 17,752 

(Angliss and Lodge, 2005). Federal protection under the ESA was removed in 1994, and further evaluation 

determined that the stock was neither in danger of extinction nor likely to become endangered in the 

foreseeable future (Rugh et al., 1999). The eastern North Pacific stock is not designated as depleted under 

the MMPA nor considered a strategic stock by NMFS. 

During the summer months, eastern north Pacific gray whales and their calves are in the northern Bering 

and Chukchi seas feeding (Tomilin, 1957; Rice and Wolman, 1971; Braham, 1984; Nerini, 1984). They are 

a coastal species, spending most of their time in waters <60 m deep. In mid-October, the whales begin 

their migration to the west coast of Baja California and the east coast of the Gulf of California to breed and 

calve (Swartz and Jones, 1981; Jones and Swartz, 1984). The northbound migration starts in mid-February 

and continues through May (Rice, 1984). 

Gray whales are bottom feeders sucking sediment from the seafloor. Their primary prey is amphipods, 

though other food items are ingested. Although gray whales probably feed opportunistically throughout 

their range, they return annually to primary feeding areas in the northern Bering Sea and Chukchi Sea (e.g. 

Nerini, 1984; Moore et al., 1986; Weller et al., 1999). During the 1982-1991 aerial surveys in the Alaskan 

Chukchi and Beaufort Seas, gray whales were associated with virtually the same habitat throughout the 

summer and the autumn (38 m depth and < 7% ice cover) (Moore and DeMaster 1997). It is likely that the 

shallow coastal and offshore-shoal areas provide habitat rich in gray whale prey, and their association and 

congregation in larger numbers with offshore shoals in the northern Chukchi Sea may indicate that these 

are important feeding areas for the expanding population (Moore and DeMaster, 1997). As the population 

expands, it is also believed that gray whales are also expanding their feeding areas in Arctic Alaska. 

Although gray whales historically concentrated their feeding activities in the Chirikov Basin of the Bering 

Sea, recent research indicates that gray whales actually are increasing their range and appearing in greater 

numbers in the Chukchi and Beaufort seas. For example, Moore et al. (2003) found that gray whale use of 

and aggregation in the Chirikov Basin of the Bering Sea has decreased, likely as a result of the combined 

effects of changing currents and a downturn in amphipod productivity. Moore et al. (2003) also found that 

the extended occurrence of gray whales in the Beaufort Sea complements observations of feeding whales 

moving north from the Bering Sea to the Chukchi Sea in summer. Research by Grebmeier et al. (2006) 

supported the conclusion that gray whales may be responding to marine ecosystem changes occurring in the 

North Pacific by shifting their foraging habitat northward to the North Shore of St. Lawrence Island and 

north of the Bering Strait. 

In addition, Moore et al. (2006) reported that Native hunters have noticed increasing numbers of gray 

whales near Barrow in late summer and autumn. Gray whale calls also were recorded each month from 

October 2003 through May 2004 northeast of Barrow, indicating that some whales did not migrate to 

California as expected (Moore et al., 2006). Clarke et al. (1989) found the northeastern-most recurring 

known gray whale feeding area to be in the Chukchi Sea southwest of Barrow. All of the research indicates 

that gray whales now are present in greater numbers in the Chukchi and Beaufort seas, with aggregations of 

feeding whales likely occurring in these areas as the animals shift foraging habitat in response to marine 

ecosystem changes. 

Gray whales are taken by both Alaskan and Russian subsistence hunters; however, most of the harvest is 

done by the Russians. The only reported takes in by Alaska Natives in the last decade occurred in 1995, 

when Alaskan Natives harvested two animals (IWC, 1997). In 1997, the International Whaling 

Commission implemented an annual cap of 140 gray whales to be taken by Russia and the U.S. (Makah 

Indian Tribe in Washington State). The Makahs are given 4 of the 140 annual takes, but the last reported 

harvest was one animal in 1999 (IWC, 2001). Annual subsistence take then averaged 122 whales from 

1999-2003 (Angliss and Lodge, 2005). 

 PEA-150 
III.F.4.a(3) Marine Fissipeds (Polar Bear). Polar bears have a circumpolar distribution throughout the 

Northern Hemisphere. There are two stocks recognized in Alaska: the southern Beaufort Sea stock and the 

Chukchi/Bering Seas stock. The southern Beaufort Sea population ranges from the Baillie Islands, Canada 

west to Point Hope, Alaska. The Bering/Chukchi population ranges from Point Barrow, Alaska west to the 

Eastern Siberian Sea. These two populations overlap between Point Hope and Point Barrow, Alaska, 

centered near Point Lay (Amstrup, 1995). 

A reliable estimate for the Bering/Chukchi Sea stock does not exist. The southern Beaufort Sea population 

was estimated at 2,272 individuals by Amstrup using unpublished data (Angliss and Lodge, 2005). Neither 

stock is listed as “depleted” under the MMPA, and the southern Beaufort Sea stock is assumed to be within 

optimum sustainable population levels (USDOI, FWS: 

http://alaska.fws.gov/fisheries/mmm/polarbear/reports.htm). The southern Beaufort Sea stock is designated 

a “non-strategic stock” by the FWS. Because of little information about the Chukchi/Bering population, 

FWS has designated it as “uncertain” at this time. 

Polar bears are common along coastlines and the southern ice edge. In the fall, polar bears are seen 

regularly during bowhead whale aerial surveys in the Beaufort Sea (Monnett and Gleason, 2006). These 

surveys suggest increased mortalities associated with receding pack ice. In northern Alaska, pregnant 

females begin excavating dens in late October-November in snow drifts in coastal areas, stable parts of the 

offshore pack ice, or on land-fast ice (Amstrup and Garner, 1994). They give birth to one to three cubs in 

December-January, and cubs remain with their mother until they are at least 2 years of age. Females will 

not rebreed until they separate from their cubs. Mating occurs from March to May, followed by a delayed 

implantation in the autumn (Ramsay and Stirling, 1988). Females give birth the following December or 

January (Harington, 1968; Jefferson, Leatherwood, and Webber, 1993). In Alaska, the maximum 

reproductive age reported for polar bears is 18 years (Amstrup and DeMaster, 1988). Polar bears usually 

forage in areas where there are high concentrations of ringed and bearded seals, as these are their primary 

prey (Larsen, 1985; Stirling and McEwan, 1975); walrus and beluga whales are also taken opportunistically 

(Amstrup and DeMaster, 1988). Polar bears are almost completely carnivorous though they will 

opportunistically feed on a variety of foods including carrion, bird eggs, and vegetation (Smith, 1985; 

Smith and Hill, 1996; Derocher, Wiig, and Bangjord, 2000). 

Polar bears are taken for subsistence, recreation, and handicrafts by Alaska Natives. Sport hunting has 

been banned since 1972. Recent harvest levels from the southern Beaufort Sea stock averaged 32 

individuals, while harvest levels of the Chukchi/Bering stock was 45 bears for a similar time period 

(Angliss and Lodge, 2005). 

III.F.4.b. Impact Assessment. Under the MMPA, it is illegal to take a marine mammal (i.e., harass, hunt, 

capture, or kill, or attempt to do so) unless prior authorization is obtained but only for activities allowed 

under the Act. “Harassment” has been further defined under the MMPA to include: “any act of pursuit, 

torment, or annoyance which: (1) Level A Harassment - has the potential to injure a marine mammal or 

marine mammal stock in the wild; or (2) Level B Harassment - has the potential to disturb a marine 

mammal or marine mammal stock in the wild by causing disruption or behavioral patterns, including, but 

not limited to, migration, breathing, nursing, breeding, feeding, or sheltering. The current levels under the 

MMPA used by NMFS to set standards for Level A and Level B harassment caused by impulse noises, 

such as from seismic surveys, include: (1) Level A Harassment (injury) at 180 dB for cetaceans and 190 

dB for pinnipeds, and (2) Level B harassment (behavioral disturbance) at 160 dB for marine mammals. 

Pacific walrus are managed by the FWS, which recently implemented a Level A harassment threshold for 

walrus of 180 dB (USDOI, FWS, 2005). These criteria often are coupled with existing data (e.g., Tolstoy et 

al., 2004) to determine exclusion zones or safety radii on a case-by-case basis based on water depths and 

airgun configurations. Field verification will be required to determine appropriate safety radii for the 

Proposed Action (see Section IV Summary of Findings, Mitigation Measures, and Recommendations). 

The marine mammals discussed in this section are exposed to a wide variety of activities, such as 

subsistence hunting; vessel movements and associated activities; aircraft; commercial fishing; climate 

change; and oil- and gas-related exploration, development, and production activities (see Section III.H 

 PEA-151 
Cumulative Impact Analysis). In general, possible effects from seismic activities include tolerance, 

masking of natural sounds, behavioral disturbance, auditory impacts (e.g., temporary and permanent 

threshold shifts), other physiological effects (Richardson et al., 1995a), and indirect effects associated with 

altered prey availability (Gordon et al., 2004). Seismic surveys, either alone or in combination with other 

factors, could have subtle, chronic effects such as: excluding marine mammals from important habitats 

(e.g., feeding, resting or molting areas) at significant times, interfering with their migrations and 

movements, contributing to habitat degradation, disrupting biologically significant behaviors, and causing 

increased levels of stress (Gordon et al., 2004). 

There is no direct information on the extent to which seismic pulses mask biologically significant sounds 

for marine mammals. However, species such as baleen whales and phocids are believed to be low 

frequency specialists, and thus more susceptible to masking by low frequency noise, such as seismic 

(Gordon et al., 2004). Since it is likely that being able to detect biologically significant signals is important 

to marine mammals’ viability, it is reasonable to assume that any reduction in this ability could have 

deleterious effects on marine mammals over very substantial distances (Gordon et al., 2004). 

It has been experimentally shown that threshold changes can be induced in both odontocetes and pinnipeds 

by exposure to intense short tones and sounds of moderate intensity for extended periods (Gordon et al., 

2004). Exposures to single short pulses have not induced threshold shifts, though it is difficult to 

extrapolate from these findings to a typical seismic survey, where animals will receive many pulses over 

the course of an exposure. Given the current state of knowledge, it is not possible to reach firm conclusions 

on the potential for seismic pulses to cause threshold shifts or hearing damage in marine mammals. 

However, the risk that seismic sources can cause hearing damage to marine mammals cannot be dismissed 

as negligible (Gordon et al., 2004). 

Seismic activities do have the potential to substantially harass and injure marine mammals by the sounds 

they generate although appropriate mitigation measures can avoid injury and limit the potential for 

behavioral disturbance. (See Section III.F.3 Threatened and Endangered Species of Marine Mammals for a 

detailed discussion of seismic sound and the potential biological impacts of seismic exploration on marine 

mammals and Section IV for a list of mitigation measures for seismic survey activities considered under 

this PEA.) It is more difficult to scientifically determine whether population level effects can result from 

long-term behavioral disturbance caused by seismic survey activity. The degree of impact of noise on 

biologically significant behavior was studied by the National Research Council’s Committee on 

Characterizing Biologically Significant Marine Mammal Behavior. The Committee concluded that it is 

unknown how or when responses of marine mammals to anthropogenic sound levels become biologically 

significant effects (NRC, 2005). In addition, a Federal Advisory Committee on Acoustic Impacts on 

Marine Mammals was convened by the Marine Mammal Commission in 2003-2005 to review and evaluate 

impacts of anthropogenic sound on marine mammals, identify areas of scientific agreement, and prioritize 

research and management needs. Although the committee was unable to reach an overall consensus on 

these issues, several findings from the Committee’s Federal Caucus report are relevant here: (1) there has 

been no scientific link between exposure to sound and adverse effects on a marine mammal population; (2) 

studies to assess population-level effects are lacking and needed; and (3) population level impacts are not 

immediately detectable. 

Behavioral impacts appear to be affected by the animal’s sex and reproductive status, age, auditory 

sensitivity, accumulated hearing damage, type of activity engaged in at the time, group size, and/or whether 

the animal has heard the sound previously and any associations it may have made with that sound (e.g., 

Olesiuk et al., 1995; Richardson et al., 1995a: Kraus et al., 1997; NRC, 2003, 2005). For example, a 

mother nursing her young might be expected to be more likely to show avoidance behavior than a male 

guarding a breeding territory. 

At present, there is little direct evidence for biologically significant effects of seismic surveys on marine 

mammals; however, none of the research projects conducted to date have been scientifically capable of 

adequately testing for effects at this level (Gordon et al., 2004). Plausible cases can be made, however, that 

observed or potential responses could result in biologically significant effects if appropriate mitigation 

cannot be implemented to lessen the potential for these effects. Therefore, Section IV provides a list of 

 PEA-152 
mitigation and monitoring measures for seismic survey activity considered under this PEA meant to avoid 

the potential for Level A Harassment (injury) and limit the potential for Level B Harassment (disturbance). 

Based on the variability of factors influencing potential impacts on marine mammals from seismic survey 

activity, the impact analysis to follow on nonendangered and nonthreatened marine mammals takes a 

cautious approach and bases conclusions on potential effects on the most sensitive members of the 

population. The conclusions then consider these potential impacts and mitigation measures outlined in 

Section IV to determine the level of potential impact from the Proposed Action and Alternatives 3 through 

6. Additional reviews on the potential impacts of seismic surveys on marine mammals can be found in 

Richardson et al. (1995a), Gordon et al. (1998), Davis et al. (1998), and USDOI, MMS (2004). 

III.F.4.b(1) Pinnipeds 

Phocids (Ringed, Spotted, Ribbon, and Bearded Seals). Pinnipeds use the acoustic properties of sea water 

to aid in navigation, social communication, and possibly predator avoidance. Most phocid seals spend 

>80% of their time submerged in the water (Gordon et al., 2004); consequently they will be exposed to 

sounds from the proposed seismic surveys. Few studies of the reactions of pinnipeds to noise from openwater exploration have been published. Temporary threshold shift (TTS) values for pinnipeds exposed to 

brief pulses (either single or multiple) of underwater sound have not been measured. 

Phocids have good low frequency hearing; thus it is expected that they will be more susceptible to masking 

of biologically significant signals by low frequency sounds, such as from seismic surveys (Gordon et al., 

2004). Masking of biologically significant sounds by anthropogenic noise is equivalent to a temporary loss 

of hearing acuity. Brief, small-scale masking episodes, might, in themselves, have few long-term 

consequences for individuals or populations of marine mammals. However, the consequences might be 

more serious in areas where many surveys are occurring simultaneously. Underwater audiograms for 

phocids suggest that they have very little hearing sensitivity below 1 kHz; they can hear underwater sounds 

at frequencies up to 60 kHz; and make calls between 90 Hz and 16 kHz (Richardson et al. 1995a). While 

seismic surveys can contain energy up to 1 kHz, most of the emitted energy is less than 200 Hz. There is 

considerable variability in the vocalizations of seals, and many of the arctic species vocalize underwater in 

association with territorial and mating behaviors. Seismic surveys are unlikely to have significant impacts 

(e.g., masking) on vocalizations associated with breeding activity due to the time of year (i.e., the survey 

will occur after the breeding season). 

Reported seal responses to seismic surveys have been variable and often contradictory, though they do 

suggest that pinnipeds frequently do not avoid the area within a few hundred meters of operating airgun 

arrays. Brueggeman et al. (1991) reported that 96% of the seals they encountered during seismic 

operations in the Beaufort Sea were encountered during non-data acquisition activities, suggesting 

avoidance of active data acquisition operations. Miller et al. (2002) reported that, on average, seals sighted 

during active seismic periods in the Beaufort Sea were significantly farther from the vessel (210 m) than 

those sighted during periods without airgun operations (150 m). At the 210-m distance, seals would have 

been exposed to sound levels of about 190 dB re 1 μPa (rms). Sighting rates of ringed seals from another 

seismic vessel in the Beaufort Sea showed no difference between periods with the full array, partial array, 

or no guns firing (Harris, Miller, and Richardson, 2001). Mean distances to seals sighted did increase 

during full array operations, however, suggesting some local avoidance at levels between 190-200 dB rms. 

By contrast, telemetry work by Thompson et al. (1998) (as cited in Gordon et al., 2004) suggests that 

avoidance and behavioral reactions to small airgun sources may be more dramatic than ship-based visual 

observations indicate. Instrumented gray (Halichoreus grypus) and harbor seals exhibited strong avoidance 

behavior of small air guns, swimming rapidly away from the seismic source. Many ceased feeding, and 

some hauled out, possibly to avoid the noise. The behavior of most of the seals seemed to return to normal 

within two hours of the seismic array falling silent. The authors suggest that responses to more powerful 

commercial arrays might be expected to be more dramatic, and occur at greater ranges. 

Seals may be disturbed by vessel traffic and aircraft associated with the seismic surveys. Disturbance may 

cause seals to leave haulout locations and enter the water. However, there are few published studies 

addressing pinniped responses to vessels and aircraft (Richardson et al., 1995a). Jansen et al. (2006) 

 PEA-153 
reported that harbor seals approached by ships at 100 m were 25 times more likely to enter the water than 

were seals approached at 500 m. However, they also reported that seal abundance in Disenchantment Bay, 

Alaska steadily increased during the summer in concert with increasing ship traffic (i.e., no short-term 

avoidance of areas used by ships), suggesting that changes in overall abundance were influenced by other 

factors. Harbor seals in their study area did aggregate more closely with increasing ship presence, similar 

to studies of other marine mammals that show denser aggregations during periods of disturbance. Born et 

al. (1999) reported that the probability of hauled out ringed seals responding to aircraft overflights with 

escape responses was greatest at lateral distances of <200 m and overhead distances <150 m. Such 

responses are likely relatively minor and brief in nature. 

It is uncertain how seismic surveys potentially might impact seal-food resources in the immediate vicinity 

of the survey. As previously discussed in Section III.F.1 (Fish, Fishery Resources, and Essential Fish 

Habitat) direct and adverse impacts affecting some prey species (i.e., some teleost fishes) may last for days 

to weeks (e.g., displacement from foraging, staging, or spawning habitat areas) or longer (i.e., auditory 

and/or vestibular harm that lasts months or even years). If seismic surveys cause pinnipeds’ prey to 

become less accessible, either because they move out of an area or become more difficult to catch, than 

pinniped distributions and feeding rates are likely to be affected. Newly weaned phocid pups may be 

particularly vulnerable to reduced feeding rates (Gordon et al., 2004), and thus may be disproportionately 

affected by seismic surveys. This is particularly pertinent considering that most phocid pups are weaned in 

June, just prior to the start of the proposed seismic surveys. Conversely, damaged or disoriented prey could 

attract pinnipeds to seismic survey areas, providing short-term feeding opportunities but increased levels of 

exposure Gordon et al., 2004).

There is no specific evidence that exposure to pulses of airgun sound can cause PTS in any marine 

mammal, even with large arrays of airguns. Direct impacts causing injury (Level A) from the seismic 

surveys likely would occur if animals entered the 190-dB zone immediately surrounding the sound source. 

A marine mammal within a radius of 100 m around a typical array of operating airguns might be exposed to 

a few seismic pulses with levels of >205 dB, and possibly more pulses if the animals moved with the 

seismic vessel. Although it is unlikely that airgun operations during most seismic surveys would cause 

PTS in marine mammals, caution is warranted given the limited knowledge about noise-induced hearing 

damage in marine mammals. However, with appropriate mitigation measures in place (e.g., marine 

mammal observers and shutdown procedures), the probability of seismic-survey-generated injuries should 

be mitigated. 

Pacific Walrus. Pacific walruses will be present in the Chukchi Sea action area during seismic-survey 

activity. Walruses do not typically frequent water depths >200 m, which may exclude them from some 

survey areas. 

Walruses produce a variety of sounds (grunts, rasps, clicks), which range in frequency from 0.1 Hz-10 Hz 

(Richardson et al., 1995a). Because vocalizations associated with breeding behavior occur during the 

winter mating season, summertime seismic-survey activities are not expected to affect their breeding 

behavior. However, walruses might be impacted by vessel and aircraft traffic associated with seismic 

surveys. Walruses will flee haulout locations in response to disturbance from aircraft and ship traffic, 

though the reaction is highly variable (Richardson et al., 1995a). Females with dependent young are 

considered the least tolerant of disturbances. Helicopters are more likely to elicit responses than fixedwing aircraft, and walrus are particularly sensitive to changes in engine noise and are more likely to 

stampede when aircraft turn or bank overhead. Researchers conducting aerial surveys for walrus in sea ice 

habitats have reported little reaction to aircraft above 1,000 feet (305 m). Brueggeman et al. (1991) 

reported that 81% of walruses encountered by vessels in the Chukchi Sea exhibited no reaction to ship 

activities within less than a kilometer, which suggests that walruses may be tolerant of levels of ship 

activities and movements. Ice management operations are expected to have the greatest potential for 

disturbances to walrus. For example, Brueggeman et al. (1991) reported that walrus moved 20-25 km from 

active icebreaking operations, where noise levels were near ambient. Conversely, researchers on board an 

icebreaker during ice management operations observed little or no reaction of hauled out walrus groups 

beyond 0.5 mile (805 m) of the vessel (Garlich-Miller, 2006, pers. commun.). Potential effects of 

prolonged or repeated disturbance include displacement from preferred feeding areas, increased stress 

 PEA-154 
levels, increased energy expenditure, masking of communication, and the impairment of thermoregulation 

of neonates that are forced to spend too much time in the water (Garlich-Miller, 2006, pers. commun.). 

Seismic surveys should have no impacts on the availability of walrus prey due to the sedentary nature of 

their prey source (primarily bivalves). 

The potential for direct impacts causing injury (Level A) from seismic surveys would be most likely if 

individuals entered the 190-dB zone immediately surrounding the high-energy sound source. With 

appropriate mitigations (e.g., marine mammal observers and shutdown procedures), it is unlikely that 

walruses would be exposed to sounds that could cause injury. Direct impacts potentially causing injury 

(Level A) from the seismic surveys also could occur if walrus hauled out on ice floes stampede into the 

water due to the approach of seismic vessels or aircraft. Calves and young animals at the perimeter of these 

haulouts are particularly vulnerable to trampling injuries and to being separated from their mothers, which 

could prove fatal. 

Most of the proposed activities will occur in areas of open water where walrus densities are expected to be 

relatively low, and monitoring requirements and mitigation measures are expected to minimize interactions 

with large aggregations of walruses. Because the proposed seismic operations will not be concentrated in 

any one area for extended periods, any impacts to walrus should be relatively short in duration, and should 

have a negligible overall impact on the Pacific walrus population. 

III.F.4.b(2) Cetaceans. During2D/3D seismic surveys, cetaceans could be adversely affected by noise and 

disturbance both from the seismic sound sources, the seismic vessel, and from related support ships, boats, 

icebreakers, and aircraft. In addition, animals could be injured by very close proximity to air gun 

discharges, seismic ships or boats, aircraft and small fuel spills. From a behavioral perspective, increased 

anthropogenic noise as what would result from the Proposed Action, could interfere with communication 

among cetaceans, mask important natural and conspecific sounds, or alter natural behaviors (i.e., 

displacement from migration routes or feeding areas, disruption of feeding or nursing). Behavioral impacts 

appear to be affected by the animal’s sex and reproductive status, age, accumulated hearing damage, type 

of activity engaged in at the time, group size, and/or whether the animal has heard the sound previously. 

(e.g., Olesiuk et al., 1995; Richardson et al., 1995a: Kraus et al., 1997; NRC, 2003, 2005). For example, 

cetacean females with calves show a heightened behavioral response to seismic noise (Henley and Ryback, 

1995 and McCauley et al., 2000). In other studies, animal reactions have been mixed during studies on the 

effects of seismic activity on feeding bowhead whales with some animals ceasing feeding and others 

continuing feeding (Fraker, Richardson, and Wursig, 1995; Richardson, Wells, and Wursig, 1985). 

Section III.F.3 of this EA outlines the potential effects of noise and disturbance from the Proposed Action 

on threatened and endangered marine mammals, with a particular focus on cetaceans. This information is 

incorporated by reference here as it directly applies to the discussion to follow on general impacts of 

seismic surveys on nonthreatened and nonendangered cetaceans. Particularly useful subsections within 

Section IIIF.3 include: (1) Potential Effects of Noise and Disturbance from Proposed Seismic Surveys; (2) 

Potential Exposure of Threatened and Endangered Marine Mammals to Seismic Survey Activities in the 

Chukchi and Beaufort Sea Program Areas (which is also relevant to nonthreatened and nonendangered 

cetaceans in these same areas); (3) Potential Effects from and Types of Seismic Surveys; and (4) Effects 

from Other Vessel Traffic Associated with Seismic Surveys. In addition, MMS (2004) contains 

information on potential seismic-survey impacts to marine mammals in the Gulf of Mexico and is 

considered in the following analysis. The following information therefore builds upon the information 

contained within Section III.F.3 and MMS (2004) and provides a summary of potential impacts from 

seismic surveys on non-threatened and non-endangered marine mammals found in the Proposed Action 

area. Conclusions are then drawn based on this impact assessment and the potential for mitigation 

measures outlined in Section IV to lessen potential impacts to determine the overall level of anticipated 

impact from the Proposed Action. 

Odontocetes or Toothed Whales (Beluga Whale, Killer Whale, and Harbor Porpoise). Among the 

odontocetes, hearing thresholds are highly species-specific. The high range of hearing sensitivity falls 

within 80-150 kHz (Richardson et al., 1995a) with the greatest sensitivity to sounds above 10 kHz (USDOI, 

 PEA-155 
MMS, 2004). Killer whales are most sensitive at 20 kHz (Szymanski et al., 1999) with an upper frequency 

limit near 120 kHz (Bain, Kriete, and Dahlheim, 1993; Bain and Dahlheim in Au, 1993:33). Harbor 

porpoise hearing ranges from 1 kHz to over 100 kHz (Richardson et al., 1995a). Beluga whales appear to 

hear sounds from as low as 40-75 Hz, although their sensitivity at these low frequencies is considered poor, 

to over 100 kHz (Richardson et al., 1995a). The sensitivity of toothed whales to high-frequency sounds is 

attributed to their use of high-frequency sound pulses in echolocation and moderately high-frequency calls 

for communication. 

Below the 10 kHz level hearing ability deteriorates for toothed whales as frequency decreases, with the 

exception of the sperm whale (Carder and Ridgway, 1990). Below 1 kHz, hearing sensitivity of 

odontocetes in considered poor although some species may be able to detect sound frequencies as low as 

60-105 Hz (USDOI, MMS, 2004) and, in the case of beluga whales, as low as 40-75 Hz (Richardson et al., 

1995a). Although most seismic survey noise is concentrated below the 1 kHz level, more recent 

measurements of airguns at sea have shown that there is some level of significant seismic energy even 

within the higher frequency levels (Goold and Fish, 1998; Sodal, 1999). So, although toothed whales, such 

as the beluga whale, killer whale and harbor porpoise, specialize in hearing ranges generally outside of the 

majority of seismic survey impulse sounds, there is still the potential for sounds from these surveys to fall 

within the acoustic sensitivity of toothed whales. 

There have been no documented instances of deaths, physical injuries, or auditory (i.e., temporary or 

permanent threshold shifts or other physiological) effects on toothed whales, or any marine mammal, from 

seismic survey activity. Despite this, MMS recognizes that it may be difficult to document injury or harm, 

and that the potential for injury may still exist, particularly if individuals entered the 180-dB zone 

immediately surrounding the high-energy source or were struck by seismic vessels or support ships 

(USDOI, MMS, 2004). However, with appropriate protective measures in place as discussed in Section IV 

(e.g., marine mammal observers and shutdown procedures), individuals are not likely to be exposed to 

sound levels that could cause injury and visual observance of the zone surrounding vessels would limit the 

potential for vessel strikes to occur. 

Overall, little research has been done to study the effects of seismic activity, and related vessel and air 

traffic, on the behavior of toothed whales other than the sperm whale. However, a number of studies are 

useful in drawing conclusions on potential impacts. For example, Van Parijs and Corkeron (2001) found 

that vessel presence can affect the acoustic behavior of dolphins, particularly mother/calf pairs, by 

increasing the rate of vocalization (perhaps in an attempt to maintain group cohesion) as vessels passed 

through the area. Other studies have shown that seismic survey pulses change the vocal behavior of 

common dolphins in the open sea (Wakefield, 2001) and that certain dolphin species are sighted less often 

in the vicinity of surveys when the guns were firing than when the guns were silent (Stone, 1996, 1997, 

1998). Morton and Symonds (2002) found in a 15-year study of killer whales in Johnstone Strait and 

Broughton Archipelago that killer whale presence was significantly lower during a seven year period when 

acoustic harassment devices (10 kHz devices with source levels of 194 dB re: 1 μPa at 1 m) were installed 

in the area and the number of whales returned to baseline estimates when the sound source was removed. 

The control population killer whales included in this study did not experience changes in individuals 

present over that same time period. Finally, Kraus et al., (1997) found acoustic alarms operating at 10 kHz 

with a source level of 132 dB re: 1 μPa at 1 m were an effective deterrent for harbor porpoises and harbor 

seals. Again, the protective measures in place as discussed in Section IV would seek to limit any potential 

effects to Level B Harassment (disturbance) and even minimize the degree of Level B Harassment that 

might occur. 

Beluga whales in Arctic Alaska consistently congregate in shallow coastal or estuarine waters during at 

least a portion of the summer. In the Eastern Chukchi, these areas of concentration are known to occur in 

Kotzebue Sound and Kasegaluk Lagoon. Research suggests these areas are likely used for molting and 

some of the largest gravel beds occur there. Beluga whales can also be found in large aggregations during 

the remainder of the summer when they are located further offshore and associated with deeper slope water. 

Additional analysis must then be considered on how seismic activity considered under this PEA may affect 

these concentrations of whales, especially when they are engaged in important biological behaviors such as 

feeding or molting. 

 PEA-156 
In reviewing these life history patterns of beluga whales and assessing the potential for disturbance from 

seismic activity, the potential exists, without appropriate mitigation, for seismic activities to displace 

whales from these areas. However, given the proposed level and short time frame of seismic activity for 

the 2006 open-water season and that mitigation measures in Section IV (and any imposed under the MMPA 

authorization process) are meant to lessen potential impacts, seismic activity at these areas potentially 

would result in an adverse but not significant impacts to beluga whales. 

It is uncertain about how seismic surveys might impact odontocete food resources (e.g., a variety of fish, 

squid, other marine mammals, and shellfish) in the immediate vicinity of the survey. As previously 

discussed in Section III.F.1 (Fish, Fishery Resources, and Essential Fish Habitat) direct and adverse 

impacts affecting some prey species (i.e. some teleost fishes) may last for days to weeks (e.g., displacement 

from foraging, staging, or spawning habitat areas) or longer (i.e., auditory and/or vestibular harm that lasts 

months or even years). 

Mysticetes or Baleen Whales (Minke and Gray Whales). Mysticetes, with their larger body and ear size 

and basilar membrane thickness-to-width ration, are low frequency hearing specialists with an auditory 

range starting at 10 Hz and possibly moving as high as 30 kHz (Ketten, 1998). The most sensitive range 

appears to occur below 1 KHz. Given that seismic surveys produce sounds in the frequency range used by 

baleen whales, including minke and gray whales, potential impacts to these species are considered greater 

than would occur with toothed whales. 

Given the greater potential for anthropogenic noise impacts on baleen whales, more research has been done 

to focus on potential effects than with toothed whales (although data is still considered limited). As with 

toothed whales, there have been no documented instances of deaths, physical injuries, or auditory 

(temporary or permanent threshold shifts or other physiological) effects from seismic surveys (USDOI, 

MMS, 2004). In 2004, the International Whaling Commission’s (IWC) Scientific Committee’s Standing 

Working Group on Environmental Concerns reviewed information related to the stranding of eight adult 

humpback whales in Brazilian waters during the 2002 breeding season that occurred while seismic surveys 

were operating in the immediate area. No clear cause of the stranding was ever found, but the IWC as a 

whole and its Scientific Committee agreed that there is compelling evidence of increasing sound levels 

having the potential to impact whales. Although no documented injuries have occurred, MMS considers 

there to still be a potential for injury to marine mammals from seismic activities. However, the mitigation 

measures outlined in Section IV are designed to avoid Level A Harassment (potential to injure) and 

maintain any takes of marine mammals at or below Level B Harassment (potential to disturb). 

Baleen whales are also subject to behavioral disturbance from the presence of anthropogenic noise. 

Overall, studies of gray, bowhead and humpback whales have shown that received levels of impulses in the 

160-170 dB re: 1 μPa rms range appear to cause avoidance behavior in a significant portion of the animals 

exposed. Dahlheim (1987) reported that in noisy environments, gray whales increase the timing and level 

of their vocalizations and use more frequency-modulated signals. Malme et al. (1986, 1988) studied the 

responses of feeding eastern gray whales to pulses from a single 100-in3

 airgun off St. Lawrence Island in 

the northern Bering Sea. They estimated, based on small sample sizes, that 50% of feeding gray whales 

ceased feeding at an average received pressure level of 173 dB re 1 μPa on an (approximate) rms basis, and 

that 10% of feeding whales interrupted feeding at received levels of 163 dB. Malme at al. (1986) estimated 

that an average pressure level of 173 dB occurred at a range of 2.6-2.8 km (1.4-1.5 nmi) from an airgun 

array with a source level of 250 dB (0-pk) in the northern Bering Sea. These findings were generally 

consistent with the results of experiments conducted on larger numbers of gray whales that were migrating 

along the California coast. Malme and Miles (1985) concluded that, during migration, changes in 

swimming pattern occurred for received levels of about 160 dB re 1 μPa and higher, on an approximate rms 

basis. The 50% probability of avoidance was estimated to occur at a CPA distance of 2.5 km (1.3 nmi) 

from a 4,000-in3 array operating off central California (CPA = closest point of approach). This would occur 

at an average received sound level of about 170 dB (rms). Some slight behavioral changes were noted at 

received sound levels of 140 to 160 dB (rms). However, these slight behavioral changes at levels below 

160 dB may have been more relevant to the location of the sound source as the seismic array was placed in 

the middle of the gray whale migratory pathway. In Würsig et al. (1999), observations of gray whales near 

 PEA-157 
Sakhalin Island found no indication that western gray whales exposed to seismic noise were displaced from 

these feeding grounds in 1999 and 2001. However, there were indications of subtle behavioral effects and 

(in 2001) localized avoidance by some individuals (Johnson 2002; Weller et al. 2002). 

Currently, gray whales are believed to congregate along offshore shoals in the northern Bering and Chukchi 

seas for feeding during the summer months. Larger aggregations of feeding whales have been reported at 

these shoals. As this may indicate that these are important feeding areas for the expanding gray whale 

population and gray whales typically have shown documented disturbance reactions at levels at or above 

160 dB, the effects of seismic surveys at these feeding sites must also be considered. The potential exists, 

without appropriate mitigation, for seismic activities to displace whales from these areas. However, given 

the proposed level and short time frame of seismic activity for the 2006 open-water season and that 

mitigation measures in Section IV (and any imposed under the MMPA authorization process) are meant to 

lessen potential impacts, seismic activity at these feeding areas potentially would result in an adverse but 

not significant impacts to gray whales. 

No studies are available specific to the effects of seismic survey noise on minke whales but the potential for 

impacts would be considered within the range of other baleen whales. Also, no known long-term impacts 

have been documented on gray and minke whale behavior as a result of seismic activity. However, 

mitigation and monitoring measures outlined in Section IV are considered to: (1) prevent Level A 

Harassment (injury); (2) lessen the potential for takes by Level B Harassment (disturbance); and (3) by 

limiting the potential for short-term harassment, ultimately avoid the potential for long-term, population 

level effects. 

III.F.4.b(3) Marine Fissipeds (Polar Bear). Impacts to polar bears from marine open-water seismic 

activity have not been studied, but would likely be minimal. When swimming, polar bears normally keep 

their heads above or at the water’s surface, where underwater noise is weak or undetectable (Richardson et 

al., 1995a). Direct impacts potentially causing injury (Level A) from the seismic surveys are possible if 

animals entered the 190-dB zone immediately surrounding the sound source. However, with appropriate 

measures in place (e.g., marine mammal observers and shutdown procedures), any potential seismicsurvey-generated injuries could be mitigated. There is also the possibility that bears could be struck by 

seismic vessels or exposed to small scale fuel spills, though these risks are considered slight. 

For most of the year, polar bears are not very sensitive to noise or other human disturbances (Amstrup, 

1993). However, pregnant females and those with newborn cubs in maternity dens are sensitive to noise 

and vehicular traffic (Amstrup and Garner, 1994). Vessel traffic associated with seismic-survey activity is 

not expected to cause impacts to polar bears, because they show little reaction to vessels and generally do 

not linger in open water. Brueggeman et al. (1991) observed polar bears in the Chukchi Sea during oil and 

gas activities and recorded their response to an icebreaker. While bears did respond (walking toward, 

stopping and watching, walking/swimming away) to the vessel, their responses were brief. Seismic surveys 

have the potential to disturb polar bears that are swimming between icefloes or between the pack ice and 

shore. Swimming can be energetically expensive for polar bears, particularly for bears that engage in longdistance travel between the leading ice edge and land. Bears that encounter seismic operations may be 

temporarily deflected from their chosen path, and some may choose to return to where they came from. 

However, bears swimming to shore are most likely heading for reliable food sources (i.e., Native-harvested 

marine mammal carcasses on shore), for which they have a strong incentive to continue their chosen 

course. Therefore, although some bears may be temporarily deflected and or inhibited from continuing 

toward land due to seismic operations, this interruption likely would be brief in duration. For bears that are 

already severely energetically stressed, however, this could prove fatal. Due to the vast area that seismic 

surveys will be conducted over, and the fact that seismic operations will be curtailed during the bowhead 

migration (due to aggregations of migrating whales), which coincides with the time that large numbers of 

bears swim for land, the number of bears affected in this manner likely would be very small. Conflict 

Avoidance Agreements are being negotiated between permit applicants and the AEWC to curtail seismic 

operations during bowhead whale-subsistence hunts. Because the whale hunts coincide with the time that 

many bears come ashore, particularly in the Kaktovik area, the impact to swimming polar bears would be 

mitigated to some extent. Ultimately, few bears are likely to be substantially affected by seismic operations 

during the open-water period. 

 PEA-158 
Polar bears are closely tied to the presence of the sea-ice platform for the majority of their life functions, 

including hunting (Amstrup, 2003). Because effective seismic surveys are relegated to operating in an icefree environment, it is unlikely that the proposed activities will impact the abundance and availability of 

ringed and bearded seals, which are the primary prey of polar bears. 

Because the proposed seismic operations will not be concentrated in any one area for extended periods, any 

impacts to polar bears should be relatively short in duration, and should have a negligible impact on polar 

bear populations. 

III.F.4.b(4) Conclusions. Potential effects from seismic survey activities on non-threatened and nonendangered marine mammals include tolerance (that is the capacity of the individuals to endure or become 

less responsive to the repeated exposure), masking of natural sounds, behavioral disturbance, auditory 

impacts (e.g., temporary and permanent threshold shifts), and other physiological effects (Richardson et al., 

1995a). Seismic surveys, either alone or in combination with other factors, could also have subtle, chronic 

effects such as: excluding marine mammals from important habitats (e.g., feeding, resting or molting 

areas) at significant times, interfering with their migrations and movements, contributing to habitat 

degradation, disrupting biologically significant behaviors, and increasing levels of stress (Gordon et al., 

2004). No documented instances of deaths, physical injuries, or auditory (temporary or permanent 

threshold shifts or other physiological) effects on marine mammals from seismic surveys have been 

reported (USDOI, MMS, 2004). 

Overall, the potential for seismic survey activities to significantly harass and injure non-threatened and 

non-endangered marine mammals is lessened through the implementation of appropriate protective 

measures as outlined in Section IV.A as well any imposed during the MMPA authorization process. These 

protective measures are designed to avoid Level A Harassment (potential to injure). Additional mitigation 

measures outlined in Section IV.B are designed to reduce uncertainty and further reduce the potential for 

harassment to occur at or below Level B Harassment (disturbance). In addition, these measures are meant 

to even further limit the potential for short-term harassment of marine mammals and thus avoiding the 

potential for long-term, population level effects. 

III.F.4.c. Impact Assessment of Alternatives. The most likely effects on marine mammals from seismic 

activity and the proposed alternatives include disturbance reactions to seismic vessels and associated 

aircraft traffic, and altered prey availability. Responses, such as fright, avoidance, and changes in behavior 

and vocalization patterns have been observed in marine mammals at ranges of tens to hundreds of 

kilometers from a sound source. Sound could also affect marine mammals indirectly by changing the 

accessibility of their prey species. Populations could be adversely affected if feeding, orientation, hazard 

avoidance, migration, or social behaviors are altered. Serious long-term consequences could also result 

from chronic exposure. Baleen whales (bowhead, fin, humpback, gray, and minke whales) are the most 

sensitive marine mammal species to anthropogenic noise in the action area. 

The potential for seismic survey activities to significantly harass and injure non-threatened and nonendangered marine mammals is lessened through the implementation of appropriate protective measures as 

outlined in Section IV.A. These mitigation measures are designed to avoid Level A Harassment (potential 

to injure) or limit the potential for harassment to occur at or below Level B Harassment (disturbance). 

Many of the measures were developed to lessen impacts to baleen whales, the most sensitive marine 

mammals to anthropogenic noise; thus these measures will also considerably decrease potential impacts to 

other non-threatened and non-endangered marine mammals. In addition, by further limiting the potential 

for short-term harassment of marine mammals, the potential for long-term, population level effects are 

avoided. 

One potential mitigation measure which was considered but not adopted was for active acoustic 

monitoring. Active acoustic monitoring utilizes sound (e.g., sonar) to detect, locate and track marine 

mammals within a certain distance of the sound source which includes and can extend beyond the 

determined exclusion zone. Generally, this involves a short sound pulse (energy) from a high power source 

(transducer) that travels through the water, reflects off an object, and travels back to the hydrophone 

 PEA-159 
receiver. Appendix E, pages 29-32 of MMS (2004) provides additional detail on active acoustic 

monitoring systems known to date and their use for monitoring exclusion zones. Essentially, MMS (2004) 

concludes that active acoustic monitoring, although holding potential for use in monitoring exclusions 

zones during seismic work, is not yet well-used in this regard, its effects are not well-documented, and 

systems are not yet readily available. In addition, the sound source used may or may not be more 

disturbing to cetaceans than the sound source being mitigated against. Behavioral impacts may be 

acceptable if the active acoustic monitoring sound source is ultimately less disturbing than the seismic 

sound source. However, information to make this determination is not readily available at this time. 

Therefore, the use of active acoustics as a marine mammal monitoring technique is not feasible and is not 

considered further here. 

The following analysis provides a comparison of the relative levels of protection to non-threatened and 

non-endangered marine mammals found in the Proposed Action area under the various alternatives, using 

the significance criteria defined in Section III.D and the mitigation measures that apply as outlined in 

Section IV. 

III.F.4.c(1) Alternative 1. The No Action alternative (No seismic survey permits issued for geophysical 

exploration activities) would not expose marine mammals in the project area to noise associated with 

seismic surveys and their associated support vessels (air and sea). Other methods to collect geophysical and 

geological data (as yet undetermined) may disturb animals in the project area in unknown, but possibly 

similar ways. 

III.F.4.c(2) Alternatives 3 through 6. Alternatives 3 through 6 are essentially the same with varying 

levels of protection for marine mammals depending on the size of an exclusion zone (Alternative 3, 120 dB 

exclusion zone; Alternative 4, 160 dB exclusion zone; Alternative 5, 120/160 dB exclusion zone; 

Alternative 6, 180/190 dB exclusion zone) and related monitoring. They all are environmentally sound, as 

they all contain protective measures to mitigate possible impacts on bowhead whales and other marine 

mammals, and would also contain additional mitigation measures to protect wildlife and subsistenceharvest resources from being adversely impacted. Theoretically, when effectively monitored, alternatives 

with the lowest dB isopleth exclusion zone (e.g., Alternative 3 at 120-dB) provide a greater level of 

protection for marine mammals from harm and harassment than those alternatives having a higher dB 

isopleth exclusion zone (e.g. Alternative 6 at 180/190-dB). In addition, Alternatives 3 through 6 would 

prohibit seismic surveys around bowheads in the spring lead system, thereby reducing potential impacts to 

other marine mammal species present in this system as well. 

Although the radii of the exclusion zones are meant to cover the area required to prevent Level A 

Harassment and limit the potential for Level B Harassment, disturbance to marine mammals from the 

projected seismic activity could extend beyond the exclusion zone if animals are exposed to moderately 

strong-pulsed sounds generated by the airguns. Variability in the size and configuration of the airgun 

arrays, water depth, and bottom properties necessitate that empirical data be collected to verify the actual 

exclusion zone. For example, based on 3-D seismic with 8-16 airguns totaling 560-1,500 in3

, these 

exclusion zones may be as large as 30 km for the 120 dB zones and as small as 100 m for the 190 dB zones, 

depending on the seismic array and environmental conditions. Field verification of the exclusion zone 

would be required under these alternatives, and the appropriate size of the exclusion zone would be based 

on these results. It is likely that the exclusion zone for these bigger arrays would be larger than what has 

been previously used, and this may result in an increased area where marine mammals may be harassed. In 

addition, as the safety zone increases in size (from 190/180-dB to 120 dB; Alternatives 3 through 6), the 

ability of vessel-based visual observers to effectively monitor the exclusion zone decreases. Therefore, 

additional monitoring techniques (i.e., aerial surveys and acoustic monitoring) or mitigation measures 

would be required for the alternatives with larger exclusion zones. 

III.F.4.c(2)(a) Pinnipeds (Ringed, Spotted, Ribbon, and Bearded Seal and Pacific Walrus). The NMFS’ 

current Level A harassment threshold for pinnipeds (excluding the pacific walrus) is 190 dB. Pacific 

walrus are managed by the FWS, and they recently implemented a 180-dB exclusion zone for walrus 

(USDOI, FWS, 2005). 

 PEA-160 
Alternatives 3 through 6 all provide exclusion zones capable of providing protection for pinnipeds in the 

project area. The exclusion zone would be the smallest for Alternative 6 (180/190 dB) and could be 

monitored visually by vessel-based observers. Conversely, Alternative 3 would provides the largest 

exclusion zone (120 dB). Increased disturbance from vessel and aircraft activity could consequently cause 

pinnipeds to leave haul-out locations and enter the water, though the response is highly variable. This 

could have a greater impact if flushing of haul out sites occurs when pups are present, as they can be more 

easily injured and separated from their mothers. Use of the 160 dB exclusion zone in Alternative 4 and in 

Alternative 5 would provide an intermediate-sized safety zone. Alternatives 3-5, when properly monitored, 

would provide exclusion zones which are sufficient for pinnipeds. 

The mitigation measures outlined in Section IV, and that apply to Alternatives 3 through 6, are set to avoid 

any takes of marine mammals by Level A Harassment. Based on the above, the fact that no injuries to 

marine mammals have been documented from seismic survey activities, and that protective measures 

outlined in Section IV are in place, MMS believes the potential for any injuries to pinnipeds from the 

proposed activity and Alternatives 3 through 6 is very limited, with Alternative 6 providing a slightly 

greater potential for Level A Harassment as its specified exclusion zone of 190 dB most closely approaches 

the lower limits of levels set by NMFS for Level A Harassment. 

Alternatives 3 through 6 require trained observers to visually monitor the exclusion zone, regardless of its 

size, and to be able to call for a shut-down if pinnipeds enter the exclusion zone. The ability of observers to 

effectively monitor the exclusion zone, and be able to call for a shut-down if pinnipeds enter the zone is 

critical to the success of the protective measures described in Alternatives 3 through 6, though it is often 

difficult to observe all pinnipeds within the exclusion zone (Gordon et al., 2004). 

The above assessment of the degree of impacts of Alternatives 3 through 6 is based solely on the protection 

afforded by the various exclusion zones and assumes effective monitoring of those zones will occur. This 

evaluation must therefore also consider any differences in the ability of Alternatives 3 through 6 to monitor 

their exclusion zones. From this standpoint, the larger exclusion zones to monitor would be Alternative 3 

and 5, respectively, with the smaller zones being Alternatives 4 and 6, respectively. Larger zones would 

require implementation of additional monitoring techniques beyond vessel-based visual monitoring, such as 

aerial surveys and acoustic monitoring, where the smaller zones would rely mainly on vessel-based visual 

monitoring. If these methods of additional monitoring are not effective, then additional mitigation 

measures would be set in place (i.e., adaptive management schemes where specific areas of higher marine 

mammal concentrations are avoided on a temporal or spatial basis). 

Because most phocid seals spend >80% of their time submerged and are particularly difficult to observe at 

sea (Gordon et al., 2004), even within 250 m of a seismic vessel (Brueggeman et al., 1991; Richardson, 

2000; Harris, Miller, and Richardson, 2001), it is possible some may be exposed to significant levels of 

received sound from the seismic array. However, pinnipeds are not likely to be exposed to sound levels 

which could cause injury, as they would have to swim within extremely close proximity to the seismic 

array in order to be vulnerable, and there is no specific evidence that exposure to pulses of airgun sound 

can cause direct injury to pinnipeds. The most likely potential impacts to pinnipeds from seismic surveys 

and associated activities would be disturbance and possible impacts to food resources. See Section III.F.4.b 

for a more detailed discussion of these impacts. 

With the mitigation included in Section IV and the MMPA authorization required for Alternatives 3 

through 6, all aircraft overflights would be required to fly at or above 1,000 ft in order to minimize the 

potential for behavioral impacts to marine mammals and adversely affect subsistence hunting. Therefore, 

the use of aerial surveys is not expected to significantly increase the potential for harassment of pinnipeds 

under Alternatives 3 and 5. Therefore, the varying degrees of impact between the alternatives, as discussed 

in the paragraphs above, remains the same with the greatest to least level of protection from behavioral 

disturbance and injury being Alternatives 3, 5, 4, and 6 respectively. 

III.F.4.c(2)(b) Cetaceans (Beluga Whale, Killer Whale, Harbor Porpoise, Minke Whale, and Gray Whale). 

NMFS’ current threshold for Level A Harassment (potential to injure) of cetaceans is 180 dB. The 

mitigation measures outlined in Section IV, and which apply to Alternatives 3 through 6, are set to avoid 

 PEA-161 
any takes of marine mammals by Level A Harassment. In addition, the MMPA authorization required 

under Alternatives 3 through 6 would not authorize any Level A takes of marine mammals. Based on the 

above, the fact that no injuries to marine mammals have been documented from seismic survey activities, 

and that protective measures outlined in Section IV are in place, MMS believes the potential for any 

injuries to cetaceans from the proposed activity and Alternatives 3 through 6 is very limited, with 

Alternative 6 providing a slightly greater potential for Level A Harassment as its specified exclusion zone 

of 180 dB most closely approaches the lower limits of levels set by NMFS for Level A Harassment. 

The NMFS’ current threshold for Level B Harassment (potential to disturb) for cetaceans is 160 dB. No 

studies have shown that toothed whales in the Proposed Action area have reacted behaviorally to seismic 

sound below the 160 dB received sound level. Studies on most baleen whales, except for the bowhead and 

gray whale, have also not demonstrated behavioral reaction at a received sound level of less than 160 dB. 

However, data exists showing that gray and bowhead whales may react behaviorally at received sound 

levels lower than 160 dB. For example, Malme and Miles (1985) found some slight behavioral changes in 

gray whales from seismic surveys at received sound levels of 140 to 160 dB (rms). However, reactions 

from gray whales at levels below 160 dB may be more relevant to the location of the sound source during 

this study as it was placed directly in the migratory path of the whales. Richardson (1999) reported that 

monitoring studies of 3-D seismic work (8-16 airguns totaling 560-1,500 in3

) in the nearshore Beaufort Sea 

during 1996-1998 have shown that nearly all bowhead whales will avoid an active seismic source at 20 km 

distance, while deflection may begin at distances up to 35 km. The received sound level at 20 km ranged 

from 117-135 dB re 1μPa rms and at 30 km was 107-126 re 1 μPa rms. Based on the results stated in 

Richardson (1999), this programmatic environmental assessment has provided two alternatives (3 and 5) 

that set exclusion zones completely or partially at 120 dB. 

In comparing Alternatives 3 through 6, looking purely at the size of the exclusion zone and assuming the 

monitoring requirements will be effective, there are differences in the level of potential behavioral impact 

across these alternatives. The most protective (i.e., resulting in the least potential for takes by Level B 

Harassment and avoidance of Level A Harassment) would be Alternative 3 as this provides the largest 

exclusion zone (120 dB) and would apply for all marine mammals. Given the bowhead whale is the only 

cetacean in the Proposed Action area to show avoidance near the 120 dB received sound levels from 

impulse sounds and all other cetaceans in the Proposed Action area have generally demonstrated avoidance 

at higher received sound levels (i.e., 160 to 180 dB), Alternative 3 would result in the least impact to 

cetaceans and other marine mammals in the Proposed Action area. 

After Alternative 3, Alternative 5 would provide the next most protective level for cetaceans. In this 

alternative, the exclusion zone would be set at 160 dB unless a certain number of bowhead whales 

(individuals, reproductive-age females, calves) were present, as determined by MMS and NMFS, where the 

exclusion zone would be changed to 120 dB. The combination of the two exclusion zones under this 

alternative would provide all cetaceans with additional protective measures but still would provide an 

exclusion zone at 160 dB (the level set by NMFS beyond which Level B Harassment is more likely to 

occur) at all remaining times. Therefore, Alternative 5 provides the next most protective alternative for 

marine mammals. 

Alternative 4 follows Alternatives 3 and 5, respectively, in the degree of potential impacts to cetaceans. 

This alternative sets the exclusion zone at 160 dB at all times, the level set by NMFS beyond which Level 

B Harassment is more likely to occur. Therefore, the greatest potential for Level B Harassment exists for 

Alternative 6 where the exclusion zone for cetaceans is set at 180 dB, which exceeds NMFS’ 160 dB 

determination for Level B Harassment (disturbance) and most closely approaches the NMFS determination 

for Level A Harassment (injury). 

The above assessment of the degree of impacts of Alternatives 3 through 6 is based solely on the protection 

afforded by the various exclusion zones and assumes effective monitoring of those zones will occur. This 

evaluation must therefore also consider any differences in the ability of Alternatives 3 through 6 to monitor 

their exclusion zones. From this standpoint, the larger exclusion zones to monitor would be Alternative 3 

and 5, respectively, with the smaller zones being Alternatives 4 and 6, respectively. Larger zones would 

require implementation of additional monitoring techniques beyond boat-based visual monitoring, such as 

 PEA-162 
aerial surveys and acoustic monitoring, where the smaller zones would rely mainly on boat-based visual 

monitoring. If these methods of additional monitoring are not effective, then additional mitigation 

measures would be set in place (i.e., adaptive management schemes where specific areas of higher marine 

mammal concentrations are avoided on a temporal or spatial basis). 

While the additional techniques required for Alternatives 3 and 5 would be costly and a larger exclusion 

zone in theory would provide a much larger, and possibly more difficult, area to monitor, this does not 

necessarily mean these larger exclusion zones are less effective in limiting impacts to cetaceans for the 

following reasons: (1) each exclusion zone in Alternatives 3 through 6 would require boat-based visual 

monitoring (i.e., all observers are scanning areas from the vessel as far as visually possible with appropriate 

equipment); (2) larger exclusion zones in Alternatives 3 and 5 would by definition require further distance 

of operating seismic vessels from cetaceans than Alternatives 4 and 6 with smaller exclusion zones; (3) the 

aerial survey and acoustic monitoring required in Alternatives 3 and 5 (and not in Alternatives 4 and 6) 

would provide additional coverage further away from the seismic source; and (4) additional mitigation 

measures would be set in place (i.e., adaptive management schemes where specific areas of higher marine 

mammal concentrations are avoided on a temporal or spatial basis) should monitoring measures prove 

ineffective. Therefore, the varying degrees of impact between the alternatives, as discussed in the 

paragraphs above, remains the same with the greatest to least level of protection from behavioral 

disturbance being Alternatives 3, 5, 4, and 6 respectively. 

The above analysis suggests that Alternatives 3 and 5 provide the most protective exclusion zones for 

cetaceans. These alternatives also incorporate the use of aerial surveys and/or acoustic monitoring (i.e., 

passively listening for the presence of marine mammal sounds) in addition to boat-based visual monitoring. 

If these methods of additional monitoring are not effective, then additional mitigation measures would be 

set in place (i.e., adaptive management schemes where specific areas of higher marine mammal 

concentrations are avoided on a temporal or spatial basis). This analysis must then determine if any 

additional disturbance caused by aircraft overflights or acoustic monitoring could impact some cetaceans 

and whether this would ultimately change the degree of impact of Alternatives 3 and 5. 

Richardson et al. (1995a) suggest that airborne sounds (and visual stimuli) from aircraft may be less 

relevant to toothed whales than baleen whales but reactions are variable. For example, beluga responses in 

offshore waters near Alaska ranged from no overt response to abrupt diving and avoidance, and generally 

increased with decreasing flight altitude. Reactions to aircraft include diving, tail slaps, or swimming away 

from the aircraft track. Gray whale mother-calf pairs seem to be sensitive while migrating gray whale 

responses are not as detectable. In other cases, both baleen and toothed whales showed no reaction to 

aircraft overflights. In summary, responsiveness depends on variables, such as the animal’s activity at the 

time of the overflight or altitude level of aircraft, and most animals quickly resume normal activities after 

the aircraft has left the area. Richardson et al. (1995a) state that there is no indication that single or 

occasional overflights can cause long-term displacement of cetaceans. 

Passive acoustic monitoring involves simply listening for cetacean sounds and occurs from a vessel-based 

system and/or hydrophone or sonobuoy placed o the seafloor. Systems are available in the commercial 

sector. They leave no acoustic footprints that could affect cetaceans and would therefore not result in any 

level of additional disturbance to cetaceans. The main drawback is that these systems can only detect 

vocalizing animals. 

With the mitigation measures outlined in Section IV and those required under the MMPA authorization 

process, all aircraft overflights would be required to fly at or above 1,000 ft in order to minimize the 

potential for behavioral impacts to marine mammals and adversely affect subsistence hunting. Therefore, 

the use of aerial surveys is not expected to significantly increase the potential for harassment of cetaceans 

under Alternatives 3 and 5. The passive acoustic monitoring requirement would also not increase the 

impact level anticipated for Alternatives 3 and 5. Additional mitigation measures would be set in place for 

the largest 120 dB exclusion zones (i.e., adaptive management schemes where specific areas of higher 

marine mammal concentrations are avoided on a temporal or spatial basis) should monitoring measures 

prove ineffective. Therefore, the varying degrees of impact between the alternatives, as discussed in the 

 PEA-163 
paragraphs above, remains the same with the greatest to least level of protection from behavioral 

disturbance and injury being Alternatives 3, 5, 4, and 6. 

III.F.4.c(2)(c). Marine Fissipeds (Polar Bear). Polar bears are managed by the FWS, and they recently 

implemented a safety radius for polar bears of 190 dB (USDOI, FWS, 2005). Because any polar bears 

encountered will most likely be on the ice, air gun effects on them are expected to be minor. If polar bears 

are encountered in the water, received sound levels would be substantially reduced due to the pressure 

release effects near the water surface (Richardson et al. 1995a). The most likely impacts to polar bears 

from seismic surveys and associated activities would be disturbance and possible impacts to bears’ food 

resources. Any impacts of seismic activity to polar bear food resources will probably be minor, local and 

brief in nature. Bearded and ringed seals are the primary prey of polar bears in the action area, and 

abundance and availability of these seals are not expected to be significantly altered by the proposed 

seismic surveys and associated activities. See Section III.F.4.b(3) for a more detailed discussion of these 

impacts. 

Alternative 6 provides the smallest exclusion zone (180/190 dB) and could be visually monitored by vesselbased observers. As the exclusion zones grow in size, it becomes less likely that the zone can be 

effectively monitored by vessel-based observers and aircraft-based observers will need to be added (i.e., 

when 120-dB level is used in Alternatives 3 and 5). Vessel activity should cause only a brief disturbance, 

with bears resuming normal activities after the vessel passes. Aircraft activity may be more problematic as 

polar bears often run away from aircraft passing at low altitude (e.g., altitude < 200 m and lateral distance < 

400 m) (Richardson et al. 1995a). The inclusion of aircraft-based observers has the potential to disturb 

more polar bears than vessel-based observers alone if the aerial observations are flown at a sufficiently low 

altitude. However, protective measures as outlined in Section IV should limit this impact. Use of the 160-

dB exclusion zone in Alternative 4 and in Alternative 5 (for the Beaufort Sea when numbers of bowhead 

whales are lower than then the pre-determined level set by NMFS and MMS (see Section III.F.3.f) will 

provide an intermediate-sized safety zone. For the Chukchi Sea, Alternatives 4 and 5 are essentially 

identical. The ability of observers to effectively monitor the exclusion zone, and be able to call for a shutdown if polar bears enter the safety zone is critical to the success of the protective measures described in 

Alternatives 3 through 6. 

III.G. Community Setting. 

III.G.1. Economy. 

III.G.1.a. Affected Environment. The economy of the North Slope Borough (NSB) and the major 

Inupiat communities it supports (Point Hope, Noatak, Point Lay, Wainwright, Barrow, Nuiqsut, and 

Kaktovik) rely heavily on oil- and gas-generated revenues generated from property taxes. The NSB 

received no OCS revenues for the period 1995-2000 (USDOI, MMS, 2003a). However, in 2001, the NSB 

did receive a share of OCS revenues through the Coastal Impact Assistance (CIA) program administered by 

the National Oceanic and Atmospheric Administration. The Energy Act of 2005 will start a new CIA 

program through 2010, and will be administered by the Minerals Management Service (MMS). 

Approximately 70% of the oil and gas workers on the North Slope commute to permanent residences in 

Alaska but outside the NSB, primarily in Southcentral Alaska and Fairbanks, and the remaining 30% reside 

outside Alaska (USDOI, MMS, 2003a). Education and other government services provide the majority of 

full-time employment in the NSB, and the NSB government employs many people directly and finances 

construction projects under its Capital Improvement Program (CIP) 

The predominately Inupiat residents of the NSB traditionally have relied on subsistence activities. 

Although not fully part of the cash economy, subsistence hunting is important to the NSB’s whole economy 

and even more important to the culture. Households do need to expend cash to purchase equipment used in 

the subsistence harvest such as boats, rifles, all-terrain vehicles, snowmachines, etc. 

Most full-time positions in Point Hope (which is on the Chukchi Sea coast) are with the city and borough 

governments. Residents manufacture whalebone masks, baleen baskets, ivory carvings, and Eskimo 

 PEA-164 
clothing. Some residents hold commercial-fishing permits. Most year-round employment opportunities in 

Point Lay are with the NSB government. Subsistence activities provide food sources. Seals, walrus, 

beluga whale, caribou, and fish are staples of the diet. 

Noatak is on the Chukchi Sea coast and its economy is based principally on subsistence, although the 

available employment is diverse. The school district, city, and retail stores are the primary employers. 

Several residents hold commercial-fishing permits. During the summer, many families travel to seasonal 

fish camps at Sheshalik, and others find seasonal work in Kotzebue or work as firefighters. 

Economic opportunities in Wainwright (which is on the Chukchi Sea coast) are influenced by its proximity 

to Barrow and the fact that it is one of the older, more established villages. Most of the year-round 

positions are in NSB services. Sale of local Eskimo arts and crafts supplements income. 

Barrow is on the Beaufort Sea coast and is the economic center of the NSB and the city’s primary 

employer. Numerous businesses provide support services to oil-field operations. State and Federal 

agencies also provide employment. Tourism and sale of arts and crafts provide some cash income. Several 

residents hold commercial-fishing permits. Many residents rely on subsistence-food sources; whale, seal, 

polar bear, walrus, duck, caribou, and grayling and whitefish are harvested from the coast or nearby rivers 

and lakes. 

Unemployment is high in Nuiqsut (which is located inland of the Beaufort Sea coast). The Kuukpik Native 

Corporation, school, NSB services, and the local store provide most of the year-round employment in the 

village. Trapping and craft making provide some income. Caribou, bowhead and beluga whale, seal, 

moose, and fish are staples of the diet. Polar bears also are hunted. 

Economic opportunities in Kaktovik, on the Beaufort Sea coast, are limited due to the community’s 

isolation, and unemployment is high. Most employment is in education, the NSB, or in providing city 

services. Part-time seasonal jobs, such as construction projects, also provide income. 

For further details on the economy of the NSB, see the final EIS for Beaufort Sea multiple-sale EIS 

(USDOI, MMS, 2003a:Section.C.1). 

III.G.1.b. Impact Assessment. Marine seismic-exploration activities themselves will not generate 

revenues for the NSB or local Alaskan Native communities, because all activities will occur in Federal 

waters of the OCS, far from shore. However, if the information collected during these seismic surveys 

leads to leasing of tracts in the Proposed Action area, NSB employment and personal income could be 

generated if further exploration, development, and production activities occur. In general, employment and 

associated personal income would be at a relatively low level in exploration, peaking during development, 

and dropping to a plateau in production. 

The MMS concludes that the economic effect of the Proposed Action and associated alternatives are not 

greater than that analyzed in the Beaufort Sea multiple-sale EIS (USDOI, MMS, 2003a), specifically that 

the Proposed Actions would not exceed the threshold for economics. The threshold for the economy is 

defined as “economic effects that would cause important and sweeping changes in the economic well-being 

of the residents of the area or region. Local employment is increased by 20% or more for at least 5 years.” 

The term “local employment” here means workers who are permanent residents of the NSB, both Inupiat 

and non-Inupiat, and does not include North Slope oil-industry workers who commute to residences within 

or outside of Alaska. 

III.G. 2. Subsistence Environment. The term “subsistence” has been defined differently by many 

(Caulfield and Brelsford, 1991; Bryner, 1995; Naiman, 1996; State of Alaska, DNR, 1997; Loescher, 

1999), but generally, subsistence is considered hunting, fishing, and gathering for the primary purpose of 

acquiring traditional food. 

The North Slope Borough Municipal Code (NSBMC) defines subsistence as: “an activity performed in 

support of the basic beliefs and nutritional needs of the residents of the borough and includes hunting, 

 PEA-165 
whaling, fishing, trapping, camping, food gathering, and other traditional and cultural activities” (NSBMC 

19.20.020 (67)). Harvest and consumption are merely the most visible aspects of such a system, and the 

most logical entry point for examining a social system with a subsistence ideology. The fundamental 

values of such societies are expressed in the idiom of subsistence, so that kinship, sharing, and subsistenceresource-use behaviors (i.e., preparation, harvest, processing, consumption, and celebration) become 

inseparable (Langdon and Worl, 1981; Elanna and Sherrod, 1984). 

The Alaska National Interest Lands Conservation Act (ANILCA) provides the operational basis for 

defining the term subsistence in this analysis (even though it has been ruled to apply only to onshore 

Federal lands and waters in Alaska, and not to offshore waters) (USDOI, FWS, 1992; Hulen, 1996a,b). 

The ANILCA defines subsistence as the customary and traditional uses by rural Alaskan residents of wild, 

renewable resources for direct personal or family consumption as food, shelter, fuel, clothing, tools, or 

transportation; for the making and selling of handicraft articles out of nonedible byproducts of fish and 

wildlife resources taken for personal or family consumption; for barter or sharing for personal or family 

consumption; and for customary trade (16 U.S.C. § 3113). 

In addition to ANILCA, other legislative acts and regulatory actions relevant to the understanding of 

subsistence management of Federal lands include the Federal Subsistence Management Regulations (36 

CFR 242 or 50 CFR 100; as summarized and available in USDOI, FWS [1992]), the Federal Advisory 

Committee Act, and the Federal Advisory Committee Management Regulations (41 CFR 101-6). The 

Marine Mammal Protection Act and Endangered Species Act also are pertinent, addressing the harvest of 

marine mammals, which currently is restricted to subsistence use by coastal Alaskan Natives. 

Examples of subsistence resources potentially affected by OCS activities, including geophysical 

exploration using seismic surveys, are marine mammals (e.g., bowhead and beluga whales, seals, and 

walruses); fishes; caribou; and waterfowl. 

III.G.2.a. Cultural Importance. “Subsistence” as a label incorporates a complex set of behaviors and 

values that extends far beyond the harvesting and consumption of wild resources, even though it is formally 

defined primarily in those terms. Worl (1979) and Nelson (1979) describe subsistence as a central focus of 

North Slope personal and group cultural identity in addition to its primary economic role. Hopson (1976, 

1978) establishes the political and ideological power of subsistence as an organizing concept for the NSB. 

Subsistence activities are assigned the highest cultural values by the Inupiat and provide a sense of identity, 

in addition to being an important economic pursuit. Many species are important for the role they play in 

the annual cycle of subsistence-resource harvests, yet effects on subsistence can be serious, even if the net 

quantity of available food does not decline. Subsistence resources provide more than dietary benefits. 

They also provide materials for personal and family, use and the sharing of resources helps maintain 

traditional Inupiat family organization. The sharing, trading, and bartering of subsistence foods structures 

relationships among communities, while at the same time the giving of these foods helps maintain ties with 

family members elsewhere in Alaska. Subsistence resources also provide special foods for religious and 

social occasions; the most important ceremony, Nalukataq, celebrates the bowhead whale harvest. 

Communities express their unique identities based on their enduring connections between current residents, 

those who used the areas in the past, and the wild resources of the land. Elders’ conferences, spirit camps, 

and other information exchange and gathering events serve to solidify these cultural connections between 

generations, and between the people and the land and its resources. 

III.G.2.b. Socioeconomic Importance. Many studies have examined the relationship between 

subsistence and wage economies and how both subsistence and wage activities are integrated into rural 

Alaskan socioeconomic systems. Although not always explicit, it is recognized that all rural communities 

and rural socioeconomic systems are not the same. One salient variable is the ethnic composition of the 

community, while another is the diversification of the local economy and the availability of wage 

employment. An extensive study series was conducted across a wide range of Alaskan communities during 

the 1980’s that focused on local patterns of wild resource use as a component of the overall economy 

(Galginaitis et al., 1984; Reed, 1985; Sobelman, 1985; Impact Assessment, Inc., 1989; Stratton, 1989, 

 PEA-166 
1990, 1992). Additional community-specific studies are cited in Fall and Utermohle (1999). Some of these 

communities are predominantly Alaskan Native, others are predominantly non-Alaskan Native, while 

others are more ethnically “mixed.” Some have developed wage (or self-employment) economies; others 

have few such opportunities. 

Within the NSB, both subsistence activities and wage economic opportunities are highly developed and 

highly dependent on each other (Kruse, Kleinfeld, and Travis., 1981; Kruse, 1982, 1991; Harcharek, 1995; 

Shepro and Maas, 1999). Those communities most active in subsistence activities tend to be those who 

also are very involved in the wage economy. That is, monetary resources are needed to effectively assist in 

the harvest of subsistence resources, both as they affect individual harvesters (e.g., to purchase a boat, 

snow machine, four-wheeler or all-terrain vehicle, fuel, and guns and ammunition) or as they affect the 

head of a collective crew (e.g., for whaling). However, full-time employment also limits the time a 

subsistence hunter can spend hunting to after-work hours. During midwinter, this window of time is 

further limited by waning daylight. In summer, extensive hunting and fishing can be pursued after work 

and without any limitations. As one North Slope hunter observed: “The best mix is half and half. If it was 

all subsistence, then we would have no money for snowmachines and ammunition. If it was all work, we 

would have no Native foods. Both work well together.” (ACI, Courtnage, and Braund, 1984). 

III.G.2.c. Community Harvest Patterns and Traditions. Rural Alaskans Statewide harvest more than 

40 million pounds (lb) of wild foodstuffs every year (Wolfe, 1996). They generally are rich in nutrients 

and contain more heart-healthy fats than many non-Native foods (Nobmann, 1997). According to 1990 

estimates (Wolfe, 1996), the annual wild food harvest in rural Alaska was 375 lb per person, compared to 

22 lb per person in urban Alaska. Assuming that, on average, 0.2 lb of wild food contains 44 grams of 

protein, and 2.94 lb of wild foods contains 2,400 kilocalories, the amount of wild food harvested in 1990 

represented 243% of the rural population’s protein requirements and 35% of the population’s calorie 

requirement. In contrast, the food reportedly harvested by urban residents represented 15% of their protein 

requirements and 2% of their calorie requirements. Clearly, wild foods represent a major source of healthy 

foodstuff in rural Alaska. 

Two major subsistence-resource categories occur on the North Slope: the coastal/marine and the 

terrestrial/aquatic. In the coastal/marine group, the food resources traditionally harvested are whales, seals, 

walruses, waterfowl, and fish. In the terrestrial/aquatic group, the resources sought are caribou, freshwater 

fishes, moose, Dall sheep, edible roots and berries, and furbearing animals. Generally, communities 

harvest resources most available to them. Harvests tend to be concentrated near communities, along rivers 

and coastlines, and at particularly productive sites. The distribution, migration, time of the year, and 

cyclical variation of animal populations make decisions on what, where, and when to harvest a subsistence 

resource very complex. Many areas might be used infrequently, but they can be quite important harvest 

areas when they are used (USDOI, BLM, 1978). For these reasons, harvest activities might occur 

anywhere in the Arctic PEA project area. 

How a village uses any particular species can vary greatly over time, and data from short-term harvest 

surveys often can lead to a misinterpretation of use/harvest trends. For example, if a particular village did 

not harvest any bowhead whales in one year, whale use would go down; consequently, consumption and 

use of caribou and other species likely would go up. If caribou were not available one winter, other 

terrestrial species could be hunted with greater intensity. The overall harvest of animal resources, such as 

marine and terrestrial mammals and fish, is heavily emphasized in the NSB; but when compared to other 

more southern areas used for subsistence by other non-NSB communities, the total spectrum of available 

resources in the NSB-region is limited. 

While subsistence-resource harvests may differ from community to community, the resource combination 

of caribou, bowhead whales, and fish is the primary grouping of resources harvested in the NSB. Caribou 

is the most important overall subsistence resource in terms of hunting effort, quantity of meat harvested, 

and quantity of meat consumed. The bowhead whale is the preferred meat and the subsistence resource of 

primary importance, because it provides a unique and powerful cultural basis for sharing and community 

cooperation (Stoker, 1984, as cited by ACI, Courtnage, and Braund, 1984). In fact, the bowhead could be 

said to be the foundation of the sociocultural system in the NSB. Depending on the community, fish is the 

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second or third most important resource after caribou and bowhead whales. Bearded seals and various 

types of birds also are considered primary subsistence species. Waterfowl are particularly important during 

the spring, when they provide variety to the subsistence diet. In the late 1970’s when bowhead whale 

quotas were low and the Western Arctic herd of caribou crashed (and the Alaska Board of Game placed 

bag limits on them), hunters turned to bearded seals (ugruk), ducks, geese, and fish to supplement the 

subsistence diet (Atqasuk could only turn to the last three resources) (Schneider, Pedersen, and Libbey, 

1980). Seal oil from hair seals and bearded seals is an important staple and a necessary complement to 

other subsistence foods. 

The subsistence pursuit of bowhead whales has major importance to the communities of Kaktovik, Nuiqsut, 

Barrow, Wainwright, and Point Hope (some Point Lay men whale with crews from Wainwright, and some 

Atqasuk men whale with Barrow crews). The sharing of whale muktuk, or fat, and whale meat is important 

to the inland community of Atqasuk and continues to be the most valued activity in the subsistence 

economy of these communities. This is true, even in light of harvest constraints imposed by quotas from 

the International Whaling Commission (IWC); relatively plentiful supplies of other resources such as 

caribou, fish, other subsistence foods; and the availability of retail grocery foods. There are regional 

exceptions to the bowhead whale-harvest tradition. In Point Lay, the beluga whale harvest is the mainstay 

of the community, and most Chukchi Sea communities rely more heavily on the harvest of walrus and seals 

than do Beaufort subsistence communities. 

Whaling traditions include kinship-based crews, use of skin boats (only in Barrow and Point Hope—

aluminum boats have almost entirely replaced skin boats for Wainwright’s spring hunt) for their spring 

whale-hunting season, distribution of the meat, and total community participation and sharing. In spite of 

the rising cash income, these traditions remain as central values and activities for all Inupiat on the North 

Slope. Bowhead whale hunting strengthens family and community ties and the sense of a common Inupiat 

heritage, culture, and way of life. Thus, whale-hunting activities provide strength, purpose, and unity in the 

face of rapid change. In terms of the whale harvest, Barrow is the only community within the planning area 

that harvests whales in the spring and fall. Wainwright and Point Hope whale only during the spring 

season and the communities of Kaktovik and Nuiqsut whale only during the fall season, although some 

Nuiqsut hunters travel to Barrow to join Barrow whaling crews during the spring whaling season (North 

Slope Borough, 1998; Alaska Consultants Inc. and S.R. Braund and Assocs., 1984). 

An important shift in community-harvest patterns occurred in the late 1960’s, when the substitution of 

snowmachines for dogsleds decreased the importance of ringed seals and walruses as key sources of dog 

food and increased the relative importance of waterfowl. This shift illustrates how technological or social 

change can lead to the modification of subsistence practices. Because of technological and harvest-pattern 

changes, the dietary importance of waterfowl also may continue to increase. However, these changes 

would not affect the central and specialized dietary roles that bowhead whales, caribou, and fish—the three 

most important subsistence-food resources to North Slope communities—play in the subsistence harvests 

of Alaska’s Inupiat, and for which there are no practical substitutes. The subsistence resources used by and 

harvest patterns of the NSB communities is described in Appendix C. The harvested resources used by 

NSB communities are identified by common species name, Inupiaq name, and scientific name in the 

Northwest National Petroleum Reserve-Alaska final EIS (USDOI-BLM and MMS, 2003:Table III.G.1). 

III.G.2.d. Concerns about Climate Change. In the NSB, a factor of increasing concern is the potential 

for adverse effects on subsistence-harvest patterns and subsistence resources from habitat and resource 

alterations due to the effects of global climate change. The Council on Environmental Quality considers 

that there is adequate scientific evidence indicating that climate change is a “reasonably foreseeable” 

impact of greenhouse gas emissions (Council on Environmental Quality, 1997; IPCC, 2001a,b). The 

Alaskan Native communities have settled in particular geographic locations because of their proximity to 

important subsistence food resources and dependable sources of water, shelter, and fuel. These 

communities and their subsistence practices will be stressed to the extent that these following observed 

changes continue: 

• settlements are threatened by sea-ice melt, permafrost loss, and sea-level rise; 

• traditional hunting locations are altered; 

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• subsistence travel and access difficulties increase; and 

• game patterns shift, and their seasonal availability changes. 

Large changes or displacements of resources would require subsistence communities to adapt quickly or 

move (Langdon, 1995; Callaway, 1995; New Scientist.com, 2002; Parson et al., 2001; AMAP, 1997; 

Anchorage Daily News, 1997; Weller, Anderson, and Nelson, 1998; IPCC, 2001a). Great decreases or 

increases in precipitation could affect local village water supplies, shift the migration patterns of land 

mammals, alter bird breeding and molting areas, affect the distribution and abundance of anadromous and 

freshwater fish, and limit or alter subsistence access routes (particularly in spring and fall) (AMAP, 1997). 

Changes in sea ice could have dramatic effects on sea mammal-migration routes and this, in turn, would 

impact the harvest patterns of coastal subsistence communities and increase the danger of hunting on sea 

ice (Callaway et al., 1999; Bielawski, 1997). Between 1980 and 2000, three sudden ice events caused 

Barrow whalers to abandon their spring whaling camps on the ice lead (George et al., 2003; National 

Assessment Synthesis Team, 2000; Groat, 2001). 

III.G.2.e. Impact Assessment Overview. The coastal environment of the Beaufort and Chukchi seas 

contains important populations of whales, pinnipeds, fishes, and birds valued by subsistence hunters in the 

region. In the Beaufort Sea, river deltas, especially the Colville and McKenzie deltas, are important 

subsistence-resource areas, as is the barrier island environment. In the Chukchi Sea, pivotal habitats 

include the Chukchi polynya open-water lead system (important to migrating whales, other sea mammals, 

and birds); the shores and offshore waters of Capes Lisburne, Lewis, and Thompson (for seabirds); Ledyard 

Bay (for seabirds); Skull Cliff Kelp Beds (important marine habitat); Kasegaluk Lagoon (for nonsalmonid 

anadromous fish; birds, beluga whales, and spotted seals); Peard Bay (for birds, anadromous fish, spotted 

seals, and belugas); Kuk River Inlet (for anadromous fish); Pitmega River and Thetis Creek deltas (for 

birds); and Point Hope Spit (for migrating birds). Cape Lisburne is an important walrus haulout site—the 

only major haulout site on the eastern Chukchi coast (Braund and Burnham, 1984).

All of the aforementioned biological resources could, to varying degrees, be impacted by geophysical 

seismic-exploration activities. As discussed in earlier sections (III.F.1-3, Biological Resources) of this 

PEA, vessel movements and traffic (seismic vessel, support vessels, ice-management vessel, etc.) and highenergy sound sources generated by the seismic-airgun arrays could adversely affect the biological resources 

of the Chukchi and Beaufort seas, including those depended on by Alaskan Natives for subsistence, if 

protective mitigation measures are not incorporated in to seismic operation plans. 

Potential effects from seismic noise and associated vessel movements could affect whaling, sealing, bird 

hunting, and fishing in the spring and open-water season. Access to subsistence resources, subsistence 

hunting, and the use of subsistence resources also could be affected by reductions in subsistence resources 

and changes in subsistence-resource-distribution patterns (USDOI, MMS, 1987:2001). 

III.G.2.e(1) Subsistence-Harvest Patterns. To understand effects on subsistence-harvest patterns, it is 

important to recognize three major conditions for regional communities: (1) they rely heavily on sea 

mammals, particularly bowhead and beluga whales, walruses, bearded seals, and fishes in the annual 

average harvest; (2) community subsistence-hunting ranges overlap for many species harvested; and (3) 

subsistence hunting and fishing are central cultural values in the Inupiat way of life. 

Subsistence land use and harvest patterns often are different among villages because of differences in 

access to game and fish, village size, and traditional patterns of use. For example, bowhead whales 

generally are accessible to hunters only at Point Hope, Wainwright, and Barrow; cliff-nesting seabirds and 

eggs are available only near Point Hope. Barrow, situated where the Chukchi and Beaufort seas meet, has 

access to resource bases from each environment (Becker, 1987). 

Because primary subsistence resources are migratory, the extent of potential impacts from oil exploration 

on subsistence hunting largely depends on the time of year that specific activity occurs and the location. 

Subsistence activities are concentrated in time and space. Should exploration activities be coincident in 

time and space such that subsistence animals are frightened away or hunter access to the animals is 

hindered, the subsistence-hunting effort may not provide the expected returns (Becker, 1987). For 

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example, seismic-survey activities that coincide in time and space with the use of the lead system by these 

animals and subsistence hunters could have potential detrimental effects (Braund and Burnham, 1984). 

The spring lead system in the Chukchi Sea is the only dependable open water available in spring; it is vital 

to subsistence hunters who hunt bowhead and beluga whales in the leads and seals, walruses, and other 

marine mammals that inhabit the retreating ice. 

For more than 30 years, representatives of the NSB, the Alaska Eskimo Whaling Commission (AEWC), the 

Northwest Arctic Borough, local tribal and city governments, and individual subsistence hunters have made 

their concerns clear about the potential impact of OCS exploration and development activity in the form of 

a list of community-specific issues: bowhead whales (problems related primarily to noise); interference 

with the spring hunt; seaward displacement of the fall migration route. Hunters believe this displacement 

has happened before and can happen again and that noise—especially that associated with seismic 

exploration—can push whales seaward by the time they get to Barrow (Becker, 1987; USDOI, MMS, 

1987d, 1990b, 1997, 2003a, 2004). 

III.G.2.e(2) Subsistence Resources. The animals commonly hunted by Natives in Chukchi and Beaufort 

sea coastal communities are bowhead and beluga whales; walruses; bearded, ringed, and spotted seals; 

polar bears; anadromous and marine fishes; waterfowl; and seabirds. The species hunted by each village 

depend mainly on proximity of harvestable populations to each village and secondarily on harvest tradition 

(Becker, 1987; USDOI, MMS, 1987d, 1990b, 1995a, 2003a, 2005). 

III.G.2.e(2)(a) Bowhead Whales. Bowhead whales can respond to noise and disturbance in a manner that 

would adversely affect the hunting of this species. Seismic surveys and associated vessels and helicopter 

traffic to and from the vessels have the potential to disturb these animals and displace them from normal 

migration patterns; such disturbance could disrupt the subsistence harvest. Generally, spring-lead whaling 

is done very quietly in man-powered skin boats. Gaining access to leads suitable for bowhead hunting 

dictates the success of North Slope whale hunters, and this access can be hindered by double leads, young 

ice, changing weather conditions, and fairly recent changes in ice thickness and extent brought on by 

changing climatic conditions in the Arctic (Braund and Burnham, 1984; USDOI, MMS, 1987d). 

If a seismic survey or support vessel were in the path of a whale chase, it could cause that particular harvest 

to be unsuccessful. Animals tend to avoid areas of high noise and disturbance and, thus, could become 

unavailable to a particular community or become more difficult to harvest. Short-term effects, such as 

flight behavior or increased wariness, also may make animals difficult to harvest. Noise and traffic 

disturbance from seismic survey vessels and non-seismic survey-related icebreakers in or near the bowhead 

whaling area could cause bowhead whales to move into the broken-ice zone and offshore leads inaccessible 

to the Inupiat hunters or under the pack ice and become unavailable to hunters. This displacement could 

have a major impact on local access and harvest success of bowhead whales. In plentiful ice years, the 

length of the whaling season still might allow a successful hunt; in a year when poor weather and ice 

conditions shortened the whaling season, such an occurrence could cause the harvest to be reduced. 

Because seismic survey activity is not planned until after July 1 and conflict avoidance measures are 

expected to be in place, such conflicts during the spring whaling season are not expected (Braund and 

Burnham, 1984; USDOI, MMS, 1987d, 1990b, 1995a, 2003a, 2005). 

Recent acoustic studies indicate that bowheads showed behavioral changes from recorded drilling and 

icebreaker noise at levels 20 dB or more above ambient levels. Whales could react to nonseismic-surveyrelated icebreaking noise at distances ranging from 2-25 km (USDOI, MMS, 2006). 

III.G.2.e(2)(b) Beluga Whales. Beluga whales are sensitive to noise and may be displaced from traditional 

harvest areas by heavy boat traffic or seismic survey noise. This disturbance response, even if brief might 

temporarily interrupt the movements of belugas or temporarily displace some animals when the vessels 

pass through an area. Such events could especially interfere with beluga movements to and from the 

lagoon areas, particularly Kasegaluk Lagoon where Point Lay hunts belugas; this harvest is concentrated 

during a few weeks in early July. Reducing or delaying the use of these habitats by belugas could affect 

their availability to subsistence hunters. Additionally, there is evidence that belugas will accommodate or 

acclimate to a particular pattern of noise after extensive exposure, and such acclimation also could affect 

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Inupiat hunter access. For example, Point Lay residents rely on the harvest of belugas more than any other 

Chukchi Sea village and, at the present time, they are very successful at herding these animals by boat into 

Kasegaluk Lagoon where they are then hunted. If noise from boat traffic and seismic survey activity 

increased and the belugas acclimated to the noise, there is the possibility that this herding technique would 

be less successful and the hunt reduced (Braund and Burnham, 1984; USDOI, MMS, 1987d, 1995a, 1998). 

In other coastal communities, belugas are harvested in the pack-ice leads in the early summer. Because the 

beluga-hunting season for Kaktovik, Barrow, Wainwright, and Point Hope takes place under two different 

conditions (in ice leads and in open water) and hunting is possible at different times over a 6-month period 

(late March-September), noise and traffic disturbance would be expected to have lesser effects; still, 

repeated vessel passes close (within 1-4 km) to both hunters and cetaceans could disturb the whale hunt. At 

present, the beluga is not intensively hunted by Barrow, Nuiqsut, or Kaktovik (USDOI, MMS, 1987d, 

1990b, 1998, 2003a). 

III.G.2.e(2)(c) Seals. Effects of noise and disturbance on seals are likely to have less important subsistence 

use effects than is the case with whales. Icebreakers could briefly disrupt some seal concentrations for up 

to a few days within a lead system, temporarily interrupt their movements, or temporarily displace some 

animals when the vessels pass through the area. However, there is no evidence to indicate that vessel 

traffic would block or significantly delay their migrations. Such traffic is not likely to have more than 

short-term effects on migrations or distributions; but the displacement of pinnipeds, polar bears, and beluga 

whales could affect the availability of these animals to subsistence hunters for that season. These shortterm, localized effects on seals could negatively affect localized subsistence hunting areas but probably not 

affect overall annual harvest levels, and seals would not become unavailable during the year. Generally, 

the seal-harvest period is longer than for whales and allows residents to harvest seals during more times 

during the year (USDOI, MMS, 1987d, 1990b, 1995a, 1998, 2003a). 

III.G.2.e(2)(d) Walrus. Impacts to walrus subsistence-harvest activities are most likely to occur during 

summer when the animals migrate from the Bering Sea into the Chukchi Sea. Walrus hunting is 

concentrated in each community’s subsistence-resource area during the open-water months, primarily from 

late May and early June through the end of August. Peard Bay is preferred by Barrow and Wainwright 

residents to harvest walruses. Helicopter traffic and seismic survey noise at this time could disturb 

walruses resting on ice pans, although it is not expected to affect walrus migration or distribution patterns. 

The common method Eskimos use to hunt walruses is to approach the herds as they rest on ice pans in the 

broken-ice margin of the pack ice. If increased seismic survey noise caused the dispersal of these herds, 

hunting success of local residents could be detrimentally affected. Noise and disturbance from aircraft 

could have localized, short-term effects that would cause some disruption to the harvest but would not 

cause walruses to become unavailable to subsistence hunters. Noise and disturbance from seismic survey 

boats and other vessels could be a problem, if boat traffic moved near marine mammal-haulout areas. 

Because seismic survey activities would are not planned until after July 1 and would avoid areas of high ice 

concentration, conflicts with the subsistence walrus hunt are not expected. The walrus hunt is much more 

important in Chukchi Sea subsistence communities; it should be noted that the subsistence walrus hunt in 

Nuiqsut and Kaktovik in recent years has not been intensive (USDOI, MMS 1987d, 1990a, 1995a, 1998, 

2003a). 

III.G.2.e(2)(e) Waterfowl. The impacts of noise and disturbance in offshore areas on waterfowl could 

disturb waterfowl-feeding and nesting activities, but these low-level biological effects are expected to be 

periodic and short term and not have significant effects on bird harvesting by coastal subsistence 

communities. Kaktovik resident Mike Edwards stated in public testimony that he thought noise would 

adversely affect the waterfowl--an important springtime source of food (Edwards, 1979, as cited in USDOI, 

BLM, 1979a; Braund and Burnham, 1984; USDOI, MMS, 1987d, 1990b, 1995a, 1998). 

III.G.2.e(2)(f) Fish Resources. The impacts of noise and disturbance in offshore areas on fish harvests 

likely would be minimal, although the increased noise potential of four concurrent seismic surveys 

(especially ocean-bottom-cable surveys in shallower waters nearshore) could displace and disturb fish 

migrations and distributions and potentially “herd” them away from traditional subsistence fishing areas 

(Braund and Burnham, 1984; USDOI, MMS, 1987d, 1990b, 1995a). 

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III.G.2.e(2)(g) Polar Bear. Active seismic survey activities are likely to result in startle responses by polar 

bears near the sound source. As with other vessel traffic, this disturbance response is likely to be brief, and 

affected animals are likely to return to normal behavior patterns within a short period of time after seismic 

vessels have left the area. Polar bears could experience short-term, localized aircraft-noise disturbanceeffects that would cause some disruption in their harvest, but this is not expected to affect annual harvest 

levels. Icebreaker noise would result only in short-term, local displacement on polar bear migrations and 

distributions, but such displacement could affect the availability of polar bears to subsistence hunters for 

that season. Because seismic-survey activities would are not planned until after July 1 and would avoid 

areas of high ice concentration, conflicts with the subsistence polar bear hunt are not expected. (USDOI, 

MMS 1987d, 1998, 2003a). 

III.G.2.e(3) Traditional Knowledge. Inupiat concern over seismic-survey disturbance is well documented. 

Don Long from Barrow stated: “Any disruption, whether it be oil spill or noise, would only disturb the 

normal migration [of bowhead whales], and a frightened or a tense whale is next to impossible to hunt” 

(Long, 1990, as cited in USDOI, MMS, 1990c). Barrow resident Eugene Brower had similar fears about 

seismic-survey disturbance, believing that noise associated with drilling, seismic survey, and other 

exploration activities will disturb the migration of the bowhead whales (Brower, 1995, as cited in USDOI, 

MMS, 1995a). The late Burton Rexford, then Chairman of the AEWC, described seismic-survey effects on 

whales in a 1993 symposium on Native whaling this way: 

 ...I had the...experience in Barrow in 1979, 1980, and 1981 of geophysical seismic work in the 

ocean, and it’s a ‘no-no’ to a hunter during the whaling migration. I know from experience. 

There were three of us captains that went out whaling in the fall. In those three years, we didn't see 

one bowhead whale, and we saw no gray whales, no beluga, and no bearded seal. We traveled as 

far as 75 miles away from our home on the ocean waters in those three years (McCartney, 1995; 

USDOI, MMS, 1998).

Nuiqsut whaling captain, Frank Long, Jr., stated that oil-industry activity offshore has affected not only 

whales but also seals and birds (Long, as cited in NMFS, 1993). Expressing concern about aircraft 

disturbance, a Nuiqsut resident and whaling captain said in recent testimony for an offshore lease sale that 

seismic traffic and helicopter overflights “were the cause of whales migrating farther north out to the ocean, 

20 miles farther north than their usual migration route” (USDOI, MMS, 1995b). Earlier, Patsy Tukle from 

Nuiqsut had expressed this same sentiment. He explained that ships and helicopters are interfering with 

whale hunting, even though they are not supposed to. He affirmed the need to enforce controls so whaling 

may go on unimpeded (Tukle, 1986, as cited in USDOI, MMS, 1986a; USDOI, MMS, 2003a). 

The late Thomas Napageak, former whaling captain, President of the Native Village of Nuiqsut, and 

AEWC Chairman, related in 1979 that he had not seen one whale while going to Cross Island every year 

and believes it is the result of seismic activity in the area (Napageak, 1979, as cited in USDOI, BLM, 

1979b). Maggie Kovalsky from Nuiqsut, testifying in 1984 on Endicott development, explained that with 

all the noise and activities, bowhead whales that migrate not far from that area all the way to Canada 

probably will be hurt (Kovalsky, 1984). In a Statewide survey by the Alaska Department of Fish and 

Game, Division of Subsistence from 1992-1994, 86.7% of the respondents in Nuiqsut believed that there 

were fewer marine mammals as a result of exploration activities on the outer continental shelf (State of 

Alaska, Dept. of Fish and Game, 1995). At a village meeting for the Northstar Project in 1996, Nuiqsut 

residents said they feared effects from the project, because it was in the migratory path of the bowhead 

whales. They made it clear that seismic surveying and transportation noise are of primary concern to 

Beaufort Sea residents because of their impacts on bowhead whales (Dames and Moore, 1996; USDOI, 

MMS, 2003a). 

The MMS is conducting long-term environmental monitoring in the region and, as part of this effort, has 

conducted a multiyear collaborative project with Nuiqsut whalers that describe present-day subsistence 

whaling practices at Cross Island to empirically verify any changes to whaling due to weather, ice 

conditions, and oil and gas activities. After the first field season of monitoring in 2001, Nuiqsut whalers 

reported the following changes in whale behavior and whaling practices: fewer whales in smaller groups 

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were seen; the need to travel farther from Cross Island to find whales; whales observed were more skittish 

than in previous years and stayed more in the ice than in open water, spent more time on the surface, and 

followed more unpredictable paths underwater; whales were more difficult to spot because blows were not 

as observable as in past years; and whales appeared to be skinnier (Note: there was no OCS seismic 

activity that year). Possible causes suggested by the whalers for these behavioral changes were: offshore 

seismic survey work for the natural gas-pipeline route; barge supply traffic to Kaktovik for a water- and 

sewer-construction project; the presence of killer whales offshore and to the east of Cross Island; ice 

conditions in Canadian waters; air and water traffic to the east of Cross Island; and general poor weather 

(Galginaitis, 2004, 2005; USDOI, MMS, 2003a).

Herman Rexford from Kaktovik recounts that oil ships affect the migration of the whales. He would like to 

see no ships or exploration off of Kaktovik during the fall whaling time. He knows that the ships are noisy 

and can affect whaling routes (Rexford, 1986, as cited in USDOI, MMS, 1986b). Herman Aishanna, 

former Kaktovik vice-mayor, recounted that “tugs make a lot of noise in the summertime” (Aishanna, 

1996, as cited in Dames and Moore, 1996). The late Barrow elder, Thomas P. Brower, Sr., began whaling 

in 1917 as a boy. He stated in a 1978 interview that: 

The whales are very sensitive to noise and water pollution. In the spring whale hunt, the whaling 

crews are very careful about noise. In my crew, and in other crews I observe, the actual spring 

whaling is done by rowing small boats, usually made from bearded sealskins. We keep our snow 

machines well away from the edge of the ice so that the machine sound will not scare the whales. 

In the fall, we have to go as much as 65 miles out to sea to look for whales. I have adapted my 

boat’s motor to have the absolute minimum amount of noise, but I still observe that whales are 

panicked by the sound when I am as much as 3 miles away from them. I observe that in the fall 

migration, the bowheads travel in pods of 60 to 120 whales. When they hear the sound of the 

motor, the whales scatter in groups of 8 to 10, and they scatter in every direction (NSB, 

Commission on History and Culture, 1980; USDOI, MMS, 2003a). 

The Bowhead Whale Feeding in the Eastern Beaufort Sea Study: Update of Scientific and Traditional 

Information, contracted by MMS, recorded a great deal of traditional knowledge of the local Kaktovikmiut 

(Kaktovik) whalers. Whaling knowledge pointed out the following: The historic core whaling area 

extends from the Hulahula River in the west to Tapkaurak Point in the east and offshore as far as 20 mi; 

most whales are taken within 18-19 mi of the village; the mean distance of harvest locations from Kaktovik 

has not changed from the 1970’s to the present; whaling captains select small whales over large whales; 

whalers have noted a significant decrease in the average size of whales harvested from the 1970’s to the 

present; two whale-feeding areas are traditionally recognized, one to the east in the Demarcation Point/Icy 

Reef area and the other near Arey Island west of Kaktovik; whales can occur near Kaktovik in July and 

August, although they are more common in Canadian waters at this time; and Kaktovik’s main hunting 

period for bowheads is in September, but whales can remain near Kaktovik as late as mid-October 

(Richardson and Thomson, 2002; USDOI, MMS, 2003a). 

According to the late Burton Rexford, former chairman of the AEWC: “Loud noises drive the animals 

away.... We know where whales can be found; when the oil industry comes into the area, the whales aren’t 

there. It is not the ice; it is the noise” (NMFS, 1993; USDOI, MMS, 1998).

In a March 1997 workshop on seismic survey effects conducted by MMS in Barrow, Alaska, with 

subsistence whalers from the communities of Barrow, Nuiqsut, and Kaktovik, whalers agreed on the 

following statement concerning the “zone of influence” from seismic survey noise: “Factual experience of 

subsistence whalers testify that pods of migrating bowhead whales will begin to divert from their migratory 

path at distances of 35 miles from an active seismic operation and are displaced from their normal 

migratory path by as much as 30 miles” (USDOI, MMS, 1998). 

III.G.2.e(4) Conclusions. Noise and disturbance impacts would be associated with the eight seismic 

surveys that are described in the scenario, with up to four permits issued in each of the Chukchi and 

Beaufort Sea action areas. Up to four concurrent seismic surveys (both 2D and 3D) could be ongoing in 

each action area for the 2006 open-water season. Surveys would not be allowed in the Chukchi Sea until 

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July 1, unless authorized by NMFS, and could continue until conditions make it impossible to conduct 

surveys; the Beaufort Sea season would begin in July and, depending on ice conditions, extend into late 

October. Ocean-bottom-cable surveys could occur in the shallower State waters of the Beaufort Sea. Four 

additional vessels (one of which could be used for ice management in emergency situations), would serve 

as support vessels for the four seismic-survey vessels. Helicopters also would be used for vessel support 

and crew changes. No estimates have been developed for the expected number of line miles of seismic 

survey to be done or the number of helicopter support flights that might be needed. 

Because the spring subsistence-whale hunt in the communities of Point Hope, Wainwright, and Barrow 

would be concluding by the time seismic activities begin in the Chukchi Sea region, adverse noise effects 

on the spring whale harvest are not anticipated.

The greatest potential disruption of the subsistence whale hunt would be expected in the traditional 

bowhead whale-hunting areas for Kaktovik, Nuiqsut, and Barrow, where multiple seismic-survey 

operations could deflect whales away from traditional hunting areas. Conflict avoidance agreements 

between the AEWC and oil operators conducting one or perhaps two seismic-survey operations per openwater season have tended to mitigate disruptions to the fall hunt in these communities, but the magnitude of 

four concurrent seismic surveys would test the ability of survey operators and whalers to coordinate their 

efforts to prevent disruptions to the hunt. 

Barrow’s fall bowhead whale hunt could be particularly vulnerable. Noise effects from multiple seismic 

surveys to the west in the Chukchi Sea and to the east in the Beaufort Sea potentially could cause migrating 

whales to deflect farther out to sea, forcing whalers to travel farther—increasing the effort and danger of 

the hunt—and increasing the likelihood of whale-meat spoilage, as the whales would have be towed from 

greater distances. Barrow’s fall hunt is particularly important, as it is the time when the Barrow whaling 

effort can “make up” for any whales not taken by other Chukchi Sea and Beaufort Sea whaling 

communities. These communities give their remaining whale strikes to Barrow, hoping that Barrow 

whaling crews will successfully harvest a whale and then share the meat back with the donating 

community. This practice puts a greater emphasis on the Barrow fall hunt. Additionally, a changing 

spring-lead condition—ice becoming thinner in recent years due to arctic warming—have made the spring 

hunt more problematic and makes the fall hunt even more pivotal in the annual whale harvest for all 

communities in the region. Thus, any disruption of the Barrow bowhead whale harvest could have 

significant effects on regional subsistence resources and harvest practices (USDOI, MMS 1987d; Brower, 

2005).

Beluga whales, when in confined areas such as spring leads or lagoons, are potentially sensitive to noise; 

however, when not restricted they appear not to be particularly sensitive. If boat traffic moved north and 

south along the coast very near Kasegaluk Lagoon and interfered with beluga whale or spotted seals 

movements to and from the lagoon, such disturbance could compromise the Point Lay subsistence effort. 

Icebreaking activities (which would only occur if a seismic-survey vessel working the Beaufort Sea became 

stuck in the ice in the fall) has been demonstrated to disturb beluga whales at much greater distances than 

bowhead whales. In summer, if vital lagoons and bays used by beluga whales and spotted seals, and a 

walrus haulout site near Cape Lisburne are not avoided by seismic-survey vessels, local harvests could be 

compromised. Any displacement of the local movements of whales, seals, and walruses by seismic survey 

noise could disturb the subsistence-harvest of a particular species. If multiple surveys were done in close 

proximity to each other, seismic survey noise could displace fish species, making them more difficult to 

harvest.

Barrow whaler Gordon Brower, stated in his comments on MMS’ 2007-2012 Proposed 5-Year Leasing 

Program: 

Barrow whalers and Nuiqsut whalers have encountered ‘unacceptable levels’ of disturbance from 

industrial activities in these waters, where whales were harvested far from ideal locations. The result 

was putting the Inupiat hunters in a greater danger by deflecting the whales as far as 30 miles off 

course; some boat[s] have succumbed to storms and greater wave actions and sunk; in some cases, 

individuals lost their lives. The harvest of the whale, therefore, was spoiled, after a 12-hour tow or 

 PEA-174 
more; the whale gasifies its internal organs and contaminates the meat, and the whale at this point 

cannot be eaten. This is a direct impact to feeding the indigenous Inupiat people of the Arctic. In 

Barrow alone, it takes a minimum of 10 whales to feed the community for a day, for the season’s 

events. Our culture is surrounded by the whale (Brower, 2005).

Even though the potential of up to four concurrent surveys being conducted in the 2006 open-water season 

in the Chukchi and the Beaufort seas is low, the additive and synergistic noise impacts produced by more 

than a single seismic survey would indicate an acoustic environment where clearly much more than a single 

sound event and a “low level” of activity is occurring; thus the approach of considering seismic-survey 

noise as a short-term and local disturbance phenomenon to these species could be considered too simplistic. 

Given the level of potential seismic-survey activity described in the scenario—four concurrent seismic 

surveys in both the Chukchi and Beaufort seas—and past assessments of species and resource effects 

discussed above, whales, pinnipeds, and polar bears might be displaced and their availability affected for an 

entire harvest season, potentially causing significant impacts. Protective mitigation measures incorporated 

into the proposed alternatives and seismic-survey permits ensures that no unmitigable adverse effects to 

subsistence resources and harvest practices would occur. 

III.G.2.f. Impacts of Alternatives on Subsistence-Harvest Patterns. 

III.G.2.f(1) Alternative 1 (No Action). The MMS would not approve seismic-survey-permit applications 

for the purpose of obtaining geophysical information about the location, extent, and properties of 

hydrocarbon resources in the Chukchi and Beaufort seas. Industry would have to rely on other measures to 

obtain needed geophysical information, such as using new data processing technology to reanalyze existing 

geophysical exploration seismic data and/or using other survey techniques, other than seismic-survey 

methodologies. Because no seismic activity would occur, no impacts to subsistence resources and practices 

would be expected. 

III.G.2.f(2) Alternatives 3, 4, 5 and 6. Alternatives 3, 4, 5, and 6 all would have similar impacts on 

subsistence harvests. The following discussion pertains to all four alternatives unless otherwise indicated. 

Seismic surveys for prelease geophysical exploration activities would be permitted with existing Alaska 

OCS exploration stipulations and guidelines and additional specific protective measures for marine 

mammals, including an isopleth-specified exclusion zone. These alternatives would permit seismic surveys 

in the Beaufort and Chukchi seas and incorporate standard G&G-permit stipulations and additional 

protective measures to ensure that fish, wildlife, and subsistence-harvest resources and practices are not 

adversely impacted. An inability to effectively perform mitigation measures would result in the suspension 

of a G&G permit until such time that the protective measures can be successfully performed and 

demonstrated. Theoretically, the larger the exclusion zone coupled with shut-down procedures, the greater 

protection of marine mammals from potential harassment and injury. Therefore, the 120-dB isoplethexclusion zone would afford more protection from harassment and injury for marine mammals than the 

180/190-dB isopleth-exclusion zone. The more marine mammals are protected, the more subsistenceharvest activities are protected. The following section discusses mechanisms for protecting subsistenceharvest activities from the possible impacts associated with the Proposed Action’s alternatives. 

An operator could propose to conduct seismic-survey activity in an area critical to whaling during the 

whaling season; however, if this condition did occur, potential conflict could be mitigated by the cessation 

of activities during the whale migration. Because fall ice conditions are not predictable events, user 

conflicts between vessels and whalers due to bad ice conditions might be more difficult to mitigate. This 

problem has been reported once for the Alaskan Arctic. In fall 1985, extreme ice conditions curtailed the 

length of Kaktovik’s whaling season and, at the same time, caused vessels traveling to their overwintering 

sites to operate near whaling locations (Smythe, 1987, pers. commun., as cited in USDOI, MMS, 1990a). 

As a result of this conflict, a cooperative program was formed in 1986 between the NSB, the AEWC, the 

Nuiqsut and Kaktovik whaling captains, and those petroleum companies interested in conducting 

geophysical studies and activities in the Beaufort Sea. This program was approved through a 

Memorandum of Understanding between NOAA and the AEWC pursuant to the 1983 Cooperative 

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Agreement, as amended. The 1986 Oil/Whalers Working Group established a communication system and 

guidelines to assure that industry vessels avoided interfering with or restricting the bowhead whale hunt 

and to establish criteria whereby the oil industry would provide certain kinds of assistance to the whalers. 

The program was successful for 2 years; however, it has been discontinued due to some difficulties with the 

communication systems and equipment. The Oil/Whalers Working Group cooperative program was a good 

example of how interference with a subsistence harvest can be effectively mitigated. In the absence of such 

mitigation, such a curtailment of the whale-harvest season due to noise could cause bowhead whales to 

become locally unavailable for the harvests in Kaktovik, Nuiqsut, Barrow, Wainwright, and Point Hope 

(USDOI, MMS, 1990b). 

Presently, individual companies are coordinating with the whalers through the auspices of the AEWC. 

Such coordination was a requirement under MMS leases for Beaufort and Chukchi Sea Sales 97,109, 144, 

170, 186, and 195. The working protocol is for the company to submit a plan of cooperation as a part of 

their exploration plan. Seismic surveying requires submission of a letter stating that cooperation will occur. 

The MMS, along with industry, their contractors, scientists, the NSB Mayor’s Office, the NSB Wildlife 

Management Department, and the AEWC, participate in the NMFS annual Peer Review Workshop to 

address monitoring issues as they relate to the NMFS administration of its responsibilities for ESA and 

Incidental Harassment Authorization (IHA) processes under the Marine Mammal Protection Act. 

Workshop participants review the results of monitoring efforts to determine the impacts of industry 

activities on marine mammals in the Beaufort Sea and review monitoring plans for the upcoming field 

season. Required mitigation similar to the lease-specific Stipulations No. 4 - Industry Site-Specific 

Bowhead Whale-Monitoring Program and Stipulation No. 5 - Conflict Avoidance Mechanisms to Protect 

Subsistence Whaling and Other Subsistence Activities and conflict avoidance measures defined in an IHA 

would specify any noise-monitoring program for marine mammals required for ongoing seismic operations 

in the Chukchi Sea and would be considered through the Peer Review Workshop meetings. Any potential 

monitoring program would be designed to: (1) assess when bowhead and beluga whales, walrus, and 

bearded seals are present in the vicinity of potential operations and the extent of behavioral effects on these 

species due to operations; (2) consider the potential scope and extent of impacts that the particular type of 

operation could have on these species; and (3) address local subsistence hunters’ concerns and integrate 

Inupiat traditional knowledge (USDOI, MMS, 2003a). 

Other coordination meetings concerning noise impacts included the Arctic Seismic Synthesis Workshop in 

Barrow in 1997, hosted by MMS that brought together Native whalers, the oil industry, and acoustic 

scientists to discuss the issue of the distance at which bowheads are deflected from their normal migration 

path by seismic noise. Whaling captains collectively presented information on distances at which bowhead 

whales reacted to seismic vessels. Other concerns raised by local subsistence hunters that pertain to 

potential seismic-noise impacts include: (1) developing a plan for minimizing the number of sealifts and 

making sure they are completed before the fall subsistence whaling season begins; and (2) developing a 

plan that ensures that local/Native observers are present during seismic activity to monitor for potential 

noise disturbance to marine mammals (USDOI, MMS, 2003a). Because the permittee is seeking a Letter of 

Authorization (LOA) or IHA for incidental take from the NMFS, the monitoring program and review 

process required under the LOA or IHA generally will satisfy the requirements of Stipulations 4 and 5. 

Mitigation similar to the lease-specific Stipulation No. 5 - Conflict Avoidance Mechanisms to Protect 

Subsistence Whaling and Other Subsistence Activities is proposed, where seismic survey operations will be 

conducted in a manner that prevents unreasonable conflicts between the oil and gas industry and 

subsistence activities (including, but not limited to, bowhead whale subsistence hunting). 

Mitigation would include submitting a plan to the MMS for activities proposed during the bowhead whalemigration period and consulting with the directly affected subsistence communities, Kaktovik, Nuiqsut, 

Barrow, Wainwright, Point Hope, Kivalina, the NSB, and the AEWC to discuss potential conflicts with the 

timing and methods of proposed operations and the safeguards or other measures that would be 

implemented by the operator to prevent unreasonable conflicts. 

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Through this consultation, the seismic-survey operator would make every reasonable effort, including such 

mechanisms as drafting a conflict avoidance agreement, to ensure that exploration activities are compatible 

with whaling and other subsistence-hunting activities and will not result in unreasonable interference with 

subsistence harvests. A discussion of resolutions reached during this consultation process and plans for 

continued consultation will be included in the exploration plan or permit. In particular, the permittee will 

show in the plan how its activities, in combination with other activities in the area, will be scheduled and 

located to prevent unreasonable conflicts with subsistence activities. 

The seismic-survey operator also would include a discussion of multiple or simultaneous operations, such 

as seismic activities, that can be expected to occur during operations to more accurately assess the potential 

for any cumulative effects. Communities, individuals, and other entities who were involved in the 

consultation will be identified in the plan. The Regional Supervisor (RS) shall send a copy of the plan to 

the directly affected communities and the AEWC at the time they are submitted to the MMS to allow 

concurrent review and comment as part of the plan approval process. In the event no agreement is reached 

between the parties, the permittee, the AEWC, the NSB, the NMFS, or any of the subsistence communities 

that could be affected directly by the proposed activity may request that the RS assemble a group consisting 

of representatives from the subsistence communities, AEWC, NSB, NMFS, and the permittee(s) to 

specifically address the conflict and attempt to resolve the issues before making a final determination on 

the adequacy of the measures taken to prevent unreasonable conflicts with subsistence harvests. 

On request, the RS will assemble this group if the RS determines such a meeting is warranted and relevant 

before making a final determination on the adequacy of the measures taken to prevent unreasonable 

conflicts with subsistence harvests. The permittee shall notify the RS of all concerns expressed by 

subsistence hunters and of steps taken to address such concerns. Permittee-related use will be restricted 

when the RS determines it is necessary to prevent unreasonable conflicts with local subsistence-hunting 

activities. In enforcing this stipulation, the RS will work with other agencies and the public to ensure that 

potential conflicts are identified and efforts are taken to avoid these conflicts. 

This stipulation, which has evolved from the Oil/Whaler Cooperative Program required in Sale 97, has 

been adopted in all Beaufort Sea sales since Sale 124, although the wording and requirements of the 

stipulation have changed over time. This stipulation helps reduce potential conflicts between subsistence 

hunters and whalers and potential oil and gas activities. This stipulation helps to reduce noise and 

disturbance conflicts from exploration operations during specific periods, such as the annual spring and fall 

whale hunts. It requires that the lessees meet with local communities and subsistence groups to resolve 

potential conflicts. This stipulation reduces the potential of adverse effects to subsistence-harvest patterns, 

sociocultural systems, and environmental justice. The above mitigation measures incorporate traditional 

knowledge and the cooperative efforts between the MMS, the State, the people of the North Slope, and 

tribal and local governments. 

This stipulation has been requested during scoping by the NSB and the AEWC. The consultations required 

by this stipulation ensure that Permittees, including contractors, consult and coordinate both the timing of 

events with subsistence activities. This stipulation has proven to be effective in mitigating prelease—

primarily seismic activities—activities through the development of the annual oil/whaler agreement 

between the AEWC and oil companies (USDOI, MMS, 2003a). 

Stipulations and required mitigation and conflict avoidance measures under MMP authorization as defined 

by NMFS and FWS should be followed in locations where the subsistence hunt is affected. The MMPA 

authorization obligates operators to demonstrate no unmitigable adverse impacts on subsistence practices. 

Conflict avoidance agreements between Permittees and the AEWC work toward avoiding unreasonable 

conflicts and disturbances to hunters and bowhead whales. Similar avoidance measures could be required 

for the subsistence beluga whale hunt by the Alaska Beluga Whale Committee (ABWC), for the 

subsistence walrus hunt by the Alaska Eskimo Walrus Commission (EWC), and for the subsistence polar 

bear harvest by the Nanuk Commission (NC). Such conflict avoidance agreements likely would follow 

protocols similar to those reached annually between Permittees and the AEWC for the subsistence bowhead 

hunt and address industry seismic-vessel activities under provisions of the MMPA. The AEWC prefers to 

negotiate a conflict avoidance agreement with industry on an annual basis using a regional rather than a 

 PEA-177 
project-specific approach, so as to address potential impacts from all ongoing projects. With the use of the 

conflict avoidance agreement methodology, Native subsistence-whale hunters generally have been 

successful in reaching their annual whale “take” quotas. 

To ensure compliance with the MMPA, MMS also is requiring seismic-survey operators to obtain from 

NMFS and FWS an Incidental Take Authorization (ITA), which could be in the form of an IHA or LOA, 

before commencing MMS-permitted seismic-survey activities. The ITA’s mitigation and monitoring 

requirements would further ensure that impacts to marine mammals will be negligible and that there will 

be no unmitigable adverse impact on subsistence uses of marine mammals. 

To achieve this standard, the seismic operators are negotiating a CAA with the AEWC and the affected 

villages’ Whaling Captains Association. The CAA likely will include a prohibition on conducting seismic 

surveys during the bowhead whale-hunting season in the Beaufort Sea, describe a dispute-resolution 

process, and provide emergency assistance to whalers at sea. Implementation of the CAA further ensures 

that there will not be significant social or economic impacts on the coastal inhabitants of the Beaufort and 

Chukchi seas by avoiding an adverse impact on subsistence marine mammal-harvest activities. 

For MMS-permitted seismic surveys, NMFS- and FWS-sanctioned observers, usually local Alaskan 

Natives and biologists employed by the monitoring contractor, are onboard survey vessels. These 

observers stop seismic operations when they observe marine mammals within the safety radius designated 

by the NMFS. Shut down of the airguns occurs if marine mammals are within this radius because of 

concern about possible effects on marine mammal hearing sensitivity (USDOI, MMS, 2003a). 

III.G.3. Sociocultural Environment. A sociocultural system encompasses the social 

organization, behavior, and cultural values of the society. This section provides a profile of the 

sociocultural environment that characterizes the communities of Kaktovik, Nuiqsut, Barrow, Atqasuk, 

Wainwright, Point Lay, and Point Hope and, whose ethnic, sociocultural, and socioeconomic makeup 

primarily is Inupiaq. 

III.G.3.a. Background. The sociocultural systems described in this document are regional and 

community systems that: (1) heavily rely on traditional Inupiat values, which include a close relationship 

with natural resources, specifically game animals; (2) are tied to supernatural beliefs; and (3) emphasize 

community, its needs, and its support of others. Although there have been substantial social, economic, and 

technological changes in Inupiat lifestyle, subsistence continues to be the central organizing values of 

Inupiat sociocultural systems. The Inupiat remain socially, economically, and ideologically loyal to their 

subsistence heritage. The hunt, the sharing of the products of the hunt, and the beliefs surrounding the hunt 

tie families and communities together, connect people to their social and ecological surroundings, link them 

to their past, and provide meaning for the present. Bowhead whale hunting remains at the center of Inupiat 

spiritual and emotional life; it embodies the values of sharing, association, leadership, kinship, arctic 

survival, and hunting prowess. 

For most Alaskan Natives, if not all, subsistence (and the relationship between people, land, water, and its 

resources) is the idiom of cultural identity. The cultural identity of Alaskan Native people also can be 

explained in terms of the sociological concept of “place.” This concept is comprised of three components 

that are key elements in understanding sociocultural systems. First, “place” is essential and spiritual. That 

is, it has a fixed and true meaning based on social facts and is an engulfing ideology. Second, it is socially 

constructed. It is negotiated, dynamic, and contested over time. This takes into account what the “place” 

was like in the past, what it has become, and how it has changed. Finally, “place” is based on geography. 

It has boundaries, and residents are connected to it as a geographic location where daily “social action” 

occurs. Much of this “social action” is in the form of subsistence. Section III.G.2 (Subsistence 

Environment) describes in detail the important roles of subsistence in various NSB communities. 

Sociocultural systems in the NSB are dynamic and influenced by many interacting causes and effects. Oil 

and gas development is only one element inducing and influencing sociocultural change in Alaska. The 

history of Native and Euro-American contact, the attainment of Statehood, and many other factors have 

combined to shape recent sociocultural change. The Federal legislative conjunction of these processes, as 

 PEA-178 
well as the passage of the ANCSA and ANILCA, also have contributed to major changes in social 

organization and cultural value systems (Chance, 1966, 1990; Arnold, 1978; Schneider, Pedersen, and 

Libby, 1980; Klausner and Foulks, 1982; Berger, 1985; Downs, 1985; Hoffman, Libbey, and Spearman, 

1988; S.R. Braund and Assocs. and UAA, ISER, 1993a,b; Alaska Natives Commission, 1994; Human 

Relations Area Files, Inc., 1994; Fall and Utermohle, 1995; State of Alaska, Dept. of Fish and Game, 1996, 

2002; Fuller and George, 1997). 

Aboriginal North Slope social organization is not well known in terms of local detail (Oswalt, 1967; 

Damas, 1984; Impact Assessment, Inc., 1989, 1990a,b; Ray, 1885; Murdoch, 1892; Nelson, 1899). The 

broad model of precontact North Slope social organization based on this evidence consists of a dynamic 

system composed of small kinship-based territorially defined “nations” of subsistence hunters (Chance, 

1966; Burch, 1970, 1975a, 1998; Damas, 1984). 

Although Euro-American contact greatly influenced Inupiat social organization, the fundamental 

organizational feature is that of kin-related groups engaged in subsistence activities—particularly the 

marine subsistence hunt of the bowhead whale. Euro-American contact introduced new resources (such as 

food items and technology) that enhanced subsistence hunting and wage-earning opportunities, as well as 

many other agents of change (Salisbury, 1992). Development of the oil industry on the North Slope 

transformed the economic basis on which the North Slope region as a whole operated, but not the 

importance of kinship-based social organization. 

Historically, perhaps the most significant social changes include the Inupiat adoption of Euro-American 

technology and the shift in Inupiat settlement patterns from a system of many small, territorially confined, 

local groups to that of a more limited number of large, permanent, communities located within a shared 

regional territory. The formation and actions of the NSB and its constituent communities are the most 

concrete expressions of these cultural continuities—a successful result of the adoption, integration, and 

manipulation of “modern” resources within an Inupiat sociocultural system (Burch 1975a,b; Hopson, 1976, 

1978; Morehouse and Leask, 1978; Worl, 1978; North Slope Borough Contract Staff, 1979; McBeath, 

1981; Kruse, 1982; Kruse et al., 1983; Morehouse et al., 1984; Harcharek, 1995; Shepro and Maas, 1999). 

Prior to the discovery and development of oil and gas on the North Slope, and the formation of the NSB in 

1972, the population of the five then-existing villages (i.e., Barrow, Kaktovik, Anaktuvuk Pass, Point 

Hope, and Wainwright) totaled about 2,500 people. Each village had limited political power, social 

services, and infrastructure. Per capita and household incomes were low; both in absolute and relative 

terms, and North Slope residents relied heavily on local subsistence resources for food, clothing, and heat 

(Van Valin, 1945; Ingstad, 1954; Sonnenfeld, 1956; Foote, 1959, 1960a,b, 1961; Spencer, 1959; Vanstone, 

1962; Gubser, 1965; Nelson, 1969; Brosted, 1975). 

Considerable information exists in the literature on the history and current dynamics of the NSB 

socioeconomics, including the resettlement of three communities since 1970 (Nuiqsut, Point Lay, and 

Atqasuk). A regional overview and a discussion of each community are provided in Impact Assessment, 

Inc. (1990), as well as within previously cited MMS documents. Both the State and the North Slope 

communities have grown significantly since 1939. The State grew at a rate that was approximately 1.5 

times that of the North Slope communities between 1939 and 1970. After 1970, as North Slope oil was 

developed, the reverse was true. The majority of NSB growth since 1970 has been in the three 

communities established after the incorporation of the NSB; however, large investments have been made in 

the infrastructures of all NSB communities (Lowenstein, 1981). Despite modernization, Inupiat society 

maintains its subsistence-based culture, with the bowhead whale hunt as an integral element. 

There have been more than 20 years of public hearings and meetings on State and Federal oil leasing, 

exploration, and development on the North Slope and in Northwest Alaska. Residents of the North Slope 

and in Chukchi Sea coastal communities have been remarkably consistent in their primary concerns during 

that time (USDOI, MMS, 1996a, 1998; U.S. Army Corps of Engineers, 1999, incorporated by reference). 

The main categories of their concern are: 

 PEA-179 
• Marine mammals, especially whales, are sensitive to noise. Hunters avoid making any sort of 

extraneous noise, and the loud and relatively constant noises associated with seismic testing, 

drilling, and boat and air transport will cause whales (and other marine mammals) to avoid areas 

where such noise is audible to them. The range of whale sensitivity to noise is quite large, and 

noise effects on bowhead whales may be the biggest concern of NSB residents. 

• Any given oil spill may be a relatively low-probability event, but over the long run the probability 

of at least one such spill occurring is quite high. Oil spills are likely to have long lasting effects 

upon the Inupiat people, primarily in terms of subsistence activities. 

• Many NSB residents believe that the technology to clean up oil spills in arctic waters, and 

especially in broken ice conditions, is poorly developed and has not been adequately demonstrated 

to be effective. 

• Many NSB residents believe that public comments at public hearings and other public forums may 

be noted, but have little or no effect on project decisions or the overall direction and philosophy of 

the leasing program. 

• There is a general fear of cultural change, especially in terms of the loss of a subsistence lifestyle, 

which may lead to social disruptions or social problems in local communities (including youth 

becoming less interested in traditional ways). 

• Oil development will result in an influx of population and other influences, which will disrupt and 

degrade Inupiat community life. In addition, oil development and its effects will impose 

additional demands upon Inupiat communities and individuals (and appearances at numerous 

hearings and the review of numerous documents are only the most visible of such demands). 

Many of the stated concerns are interrelated and based on traditional knowledge. The isolated “examples” 

with each bullet are only examples but provide at least a minimal guide for the reader in understanding the 

context from which the generalized concern was formed. This context, as it relates to noise impacts, will 

be developed further in the analysis of potential effects. 

III.G.3.b. Sociocultural Community Profiles. The following describes the Alaskan North Slope and 

Chukchi Sea communities that might be affected by geophysical exploration seismic surveys. Descriptions 

include factors relevant to the sociocultural analysis of each community in relation to industrial activities, 

population, and current socioeconomic conditions. The primary sociocultural variables—population, social 

organization, cultural values, and institutional organization—have not altered since MMS’ Beaufort Sea 

Multiple-sale final EIS appeared in 2003 and the Beaufort Sea Sale 195 EA was published in 2004. 

III.G.3.b(1) Kaktovik. Incorporated in 1971, Kaktovik is the easternmost village in the NSB. Its 

population 2004 population of 284 was 84.0% Inupiat (State of Alaska, Dept. of Community and Economic 

Development [DCED], 2005). The village is on the north shore of Barter Island situated between the 

Okpilak and Jago rivers on the Beaufort Sea coast, and is located 300 mi east of Barrow. Kaktovik abuts 

the Arctic National Wildlife Refuge; its coastal and marine subsistence-harvest areas are in and adjacent to 

areas potentially affected by seismic surveys. However, subsistence is highly dependent on caribou. Until 

the late 19th Century, the island was a major trade center for the Inupiat and was especially important as a 

bartering place for Inupiat from Alaska and Inuit from Canada. Possession of alcohol is banned in the 

community. 

III.G.3.b(2) Nuiqsut. Nuiqsut sits on the west bank of the Nechelik Channel of the Colville River Delta, 

about 25 mi inland from the Arctic Ocean and approximately 150 mi southeast of Barrow. Its 2000 

population of 433 was 89.1% Inupiat Eskimo (State of Alaska, DCED, 2005). Nuiqsut, one of three 

abandoned Inupiat villages in the North Slope region identified in ANCSA, was resettled in 1973 by 27 

families from Barrow. Today, Nuiqsut is experiencing rapid social and economic change due to the 

development of new local infrastructure, including natural gas hookups soon to come to all community 

households, the development of the Alpine facility and potential Alpine Satellite development, and 

potential oil development in the National Petroleum Reserve in Alaska (NPR-A). Most of Nuiqsut’s 

marine subsistence-harvest area lies adjacent to areas in the Beaufort Sea potentially to be seismic surveyed 

in 2006. Nuiqsut’s important bowhead whale-hunting area is at Cross Island. 

 PEA-180 
Local testimony at a 2003 public hearing for the Alpine Satellite Development Plan (USDOI, BLM, 2004) 

provides some insight at to the community’s values and concerns. Rosemary Ahtuangaruak, Mayor of 

Nuiqsut, observed that although the village ethnic makeup had not changed, oil-development infrastructure 

was creeping closer to the community and bringing with it new health issues, including an increasing 

number of asthma cases. Testifying at the same meeting, Bernice Kaigelak commented that the 

qualifications for Natives to get local oil-industry jobs had gotten more prohibitive. Testing used to be 

restricted to passing a urinary analysis but recently had been extended to other licensing requirements, 

many of which were hard to get certification for in a small community like Nuiqsut.

III.G.3.b(3) Barrow. Barrow is the largest community on the North Slope and is its regional center. In 

1970, the Inupiat population of Barrow represented 91% of the total population (USDOC, Bureau of the 

Census, 1971), but by 1990, Inupiat representation had dropped to 63% and remains approximately there 

today. Between 1980 and 1985, Barrow’s population grew by 35% (Kevin Waring Assocs., 1989). 

Barrow’s population stood at 4,351 in 2004 (State of Alaska, DCED, 2005). The dramatic change in 

population and demographics is due primarily to the impacts of oil and gas development. Increased 

revenues from onshore oil development and production at Prudhoe Bay and in other smaller oil fields have 

fueled the change. These revenues stimulated NSB Capital Improvements Projects (CIP’s) which, in turn, 

stimulated a boom in Barrow’s economy and an influx of non-Alaskan Natives to the community. The 

social organization of the Barrow community has become diversified with the proliferation of formal 

institutions and the large increase in the number of different ethic groups. Traditional marine mammal 

hunts and other subsistence practices are still an active part of the culture. The sale of alcohol is banned in 

the community, although importation or possession is allowed. 

III.G.3.b(4) Atqasuk. Atqasuk is a small, predominantly Inupiat community on the Meade River, about 60 

mi south of Barrow. In 2000, there were 228 residents, 94.3% of whom were Inupiat; in 2004, there were 

247 community residents (State of Alaska, DCED, 2005). The area has traditionally been hunted and 

fished by Inupiat Eskimos. The name means “the place to dig the rock that burns.” During World War II, 

bituminous coal was mined in Atqasuk and freighted to Barrow for use by government and private 

facilities. The community was established in mid-1970 under ANCSA by Barrow residents who had 

traditional ties to the area. People lived in tents until NSB-sponsored housing arrived in 1977. The 1980 

Census tallied 107 residents; 2 years later, a Borough census recorded 210 residents. By July 1983, the 

population had risen to 231, a 166% increase since the first census in 1980. 

Atqasuk is an inland village, and its subsistence preferences are caribou and fish. Grayling, whitefish, 

caribou, geese, ptarmigan, polar bear, seal, walrus, and whale are harvested and traded. Residents trap and 

sell furs to supplement cash income. Social ties between Barrow and Atqasuk remain strong, and men from 

Atqasuk go to Barrow to join bowhead-whaling crews. To a large degree, Atqasuk has avoided the rapid 

social and economic changes experienced by Barrow and Nuiqsut brought on by oil-development activities, 

but future change could accelerate as a result of oil exploration and development in the Northwest NPR-A 

Planning Area. Possible new pipeline routes could cross Atqasuk’s terrestrial subsistence-harvest areas, as 

most of its traditional subsistence-use area is within the NPR-A (USDOI, BLM and MMS, 2003). 

III.G.3.b(5) Wainwright. Wainwright is located on the Chukchi Sea 100 mi southwest of Barrow on the 

western boundary of the NPR-A. In 2004, Wainwright’s population was 531(State of Alaska, DCED, 

2005). As in other North Slope communities, the changes in Wainwright from 1975-1985, stimulated by 

the NSB CIP boom, are not as dramatic as the changes in Barrow. Nonetheless, the CIP led to retention of 

the population and the creation of new jobs, housing, and infrastructure. Although there has been an influx 

of non-Natives into Wainwright, most are transient workers and cannot be considered permanently settled 

or even long-term residents. In 1989, approximately 8.7% of all Wainwright residents were non-Native 

(NSB, Dept. of Planning and Community Services, 1989). This was a decrease from 30% non-Alaska 

Native in 1983 (Luton, 1985) and is most likely a direct result of the end of the NSB CIP boom. Of these 

approximately 43 residents, only a few remained in Wainwright 6 months to a year later. The Caucasians 

in Wainwright tend to be nonpermanent, mobile residents who have relatively little interaction with the 

Native population (Luton, 1985). 

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The Wainwright CIP has not only been central to the local economy, but it also has changed the face of the 

community and affected the quality of life. Residents now live in modern, centrally heated homes with 

running water, showers, and electricity. New buildings dominate the town and upgraded roads have 

encouraged more people to own vehicles. Between July 1982 and October 1983, the number of pickup 

trucks and automobiles in Wainwright more than tripled (Luton, 1985). All of Wainwright’s subsistence 

marine resources are harvested in offshore in the Chukchi Sea, and all of the community’s terrestrial 

subsistence use areas are within NPR-A (USDOI, BLM and MMS, 2003). Bowhead and beluga whales, 

seals, walruses, caribou, polar bears, birds, and fishes are harvested. Sale of local Eskimo arts and crafts 

supplements income.

III.G.3.b(6) Point Lay. Point Lay is one of the more recently established Inupiaq villages on the Arctic 

coast, and has historically been occupied year-round by a small group of one or two families. The 

community has the smallest population of any community in the NSB, with a population of 251 in 2004, 

and is the only unincorporated community in the NSB (State of Alaska, DCED, 2005). About 90 mi 

southwest of Wainwright, the community sits on the Chukchi Sea coast at the edge of Kasegaluk Lagoon 

near the confluence of the Kokolik River and Kasegaluk Lagoon. 

The community was established in the 1920’s and its number of residents increased until the 1930’s, when 

its population began a slow decline, largely because of the decline in reindeer herding. By 1960, it was not 

included in the national census. The village was reestablished on a barrier island spit opposite the Kokolik 

River in the 1970’s (motivated by the terms of ANCSA). Residents of Barrow, Wainwright, Point Hope, 

Kotzebue, and other Inupiat with traditional ties to the area resettled here. The town then moved to its 

present mainland site south of the Kokolik Delta in 1981. In 1983, a NSB census recorded 126 residents in 

the community. Local employment during this period revolved around DEW Line and Borough CIP 

projects. Smaller Borough-, village corporation-, and State-funded construction projects continue to 

employ local workers on a temporary basis, and the NSB government remains the largest local full-time 

employer (USDOI, BLM and MMS, 2003). 

Limited oil-exploration activity has occurred near Point Lay, with a well drilled 25 mi northeast of the 

community in 1981 on Arctic Slope Regional Corporation lands, the Tunalik #1 test well drilled within 

NPR-A inland and southeast of Icy Cape in 1978 and 1979. Both wells were plugged and abandoned. 

Point Lay is similar to Atqasuk in avoiding the rapid social and economic changes experienced by Barrow 

and Nuiqsut from past oil development activities. 

Point Lay residents enjoy a diverse resource base including marine and terrestrial animals. The community 

is unique because its wild food dependence is relatively balanced between marine and terrestrial resources; 

and unlike the other communities discussed, local hunters do not pursue the bowhead whale because the 

deeply indented shoreline has prevented effective bowhead whaling. However, the village participates in 

beluga whaling.

III.G.3.b(7) Point Hope. Point Hope residents, with a population of 726 in 2004 (State of Alaska, DCED, 

2005) enjoy a diverse resource base that includes both terrestrial and marine animals. Bowhead and beluga 

whales, seals, caribou, polar bears, birds, fishes, and berries are important subsistence resources. The 

community, 330 mi southwest of Barrow and is located on a large gravel spit that forms the westernmost 

extension of the northwest Alaska coast. Once called Tigaraq, the peninsula has been occupied for at least 

2,000 years and is one of the longest continuously occupied areas in Alaska. This likely is due to its 

proximity to marine mammal-migration corridors and favorable ice conditions that allow hunting in open 

leads early in the spring-whaling season. Local government is the main employer of Point Hope residents. 

Additionally, the local manufacture of Alaskan Native crafts also contributes to the community economy 

(U.S. Army Corps of Engineers, 2005).

The city government was incorporated in 1966 and, in the early 1970’s, the community moved, because of 

erosion and periodic storm-surge flooding, to its present location just east of the old settlement. The Native 

Village of Point Hope is a federally recognized tribe and is active in community government and in 

providing services. The NSB provides all utilities to Point Hope and subsidizes fuel costs. No roads 

connect Point Hope with other communities. Point Hope has better facilities than many other communities 

 PEA-182 
of the region, but problems remain concerning high fuel costs, uncertain transportation, erosion, stormsurge flooding, unemployment, and the need for better utilities (Fuller and George, 1997; U.S. Corps of 

Engineers, 2005). The sale, importation, or possession of alcohol is banned in the village. 

III.G.3.c. Impact Assessment Overview. The primary aspects of the sociocultural systems covered in 

this analysis are: (1) social organization; (2) cultural values; and (3) subsistence and social health. For 

purposes of analysis, it is assumed that effects on social organization and cultural values could be brought 

about at the community level by increased effects on subsistence-harvest patterns that could be associated 

with seismic-survey activity. Potential effects are evaluated relative to the tendency of introduced social 

forces to support or disrupt existing systems of organization, relative to how rapidly they occur and their 

duration (Langdon, 1996; USDOI, MMS, 2003a).

III.G.3.c(1) Social Organization. An analysis of the effects on sociocultural systems must first look at the 

social organization of a society that involves examining how people are divided into social groups and 

networks. Social groups generally are based on kinship and marriage systems and on nonbiological 

alliance groups formed by such characteristics as age, sex, ethnicity, community, and trade. Kinship 

relations and nonbiological alliances serve to extend and ensure cooperation within the society. 

Disruption of the subsistence cycle could change the way social groups are organized. The sharing of 

subsistence foods is profoundly important to the maintenance of family ties, kinship networks, and a sense 

of community well-being. In rural Alaskan Native communities, task groups associated with subsistence 

harvests are important in defining social roles and kinship relations: the individuals one cooperates with 

help define kin ties, and the distribution of specific tasks reflects and reinforces the roles of husbands, 

wives, grandparents, children, friends, and others. Disruption of these task groups can damage social bonds 

that hold a community together. Any serious disruption of sharing networks can appear as a threat to the 

established way of life in a community and can trigger an array of negative emotions—fear, anger, and 

frustration—in addition to a sense of loss and helplessness. Because of the psychological importance of 

subsistence in these sharing networks, perceived threats to subsistence activities from oil exploration 

activities are a major cause for anxiety. 

An Alaska Department of Fish and Game social-effects survey administered by the Division of Subsistence 

Management in 1994 in Nuiqsut included questions on effects from OCS development. One question 

asked was: “How do you think the offshore development of oil and gas in this area would affect the 

following resources available for harvest; would the resource decrease, not change, or increase?” Eightypercent of Nuiqsut respondents answered that fish resources would decrease, 87% said marine mammals 

would decrease, 43% said land mammals would decrease, and 55% said that birds would decrease; 67% 

were not in favor of the search for oil, and 42% believed the search for oil would have an adverse impact 

on subsistence; 68% were not in favor of the development and production of oil, and 52% believed that oil 

development and production would have an adverse impact on subsistence (Fall and Utermohle, 1995). 

III.G.3.c(2) Cultural Values. An analysis of a social group’s cultural values is desirable and represents 

what is accepted, explicitly or implicitly, by its members. Forces powerful enough to change the basic 

values of an entire society would include a seriously disturbing change in the physical conditions of life⎯a 

fundamental cultural change imposed or induced by external forces. One example would be an incoming 

group that demands that residents accept their intrusive culture’s values. Another would be a basic series 

of technological inventions that change physical and social conditions. Such changes in cultural values can 

occur slowly and imperceptibly or suddenly and dramatically (Lantis, 1959). Disturbances to subsistenceharvest patterns from seismic surveys might induce such a change, i.e., changes to cultural values on the 

North Slope, including strong ties to Native foods, to the land and its wildlife, to the family, to the virtues 

of sharing the proceeds of the hunt, and to independence from institutional and political forces outside the 

North Slope. 

For the system of sharing to operate properly, some households must be able to produce, rather 

consistently, a surplus of subsistence goods; it is obviously more difficult for a household to produce a 

surplus than to simply satisfy its own needs. For this reason, sharing—and the supply of subsistence foods 

in the sharing network—often is more sensitive to harvest disruptions than the actual harvest and 

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consumption of these foods by active producers. Thus, when disturbance occurs from oil exploration and 

development, it may disrupt a community’s culture, even though it does not cause “biologically significant” 

harm to a subsistence species’ overall population. 

III.G.3.c(3) Subsistence and Social Health. Stress would occur if a village were not successful in the 

bowhead whale harvest, with potential disruption of sharing networks and task groups. This stress could 

disrupt the community’s social organization but likely would not displace the long-term social processes of 

whaling and sharing, if it did not occur often. Other more successful villages would share with a village 

having an unsuccessful whaling season. There have been no unsuccessful whaling seasons for Nuiqsut 

since 1994 and Kaktovik since 1991 (Braund, Marquette, and Bockstoce, 1988; Alaska Eskimo Whaling 

Commission, 1987-1995), and negotiated conflict resolution agreements between the AEWC, subsistencewhaling communities, and the oil industry have successfully served as a means to coordinate whaling 

activities and potential disturbance to whaling from industry activities. 

Any effects on social health would have ramifications on social organization. On the other hand, NSB 

Native communities have, in fact, proven quite resilient to such effects with the Borough’s continued 

support of Inupiat cultural values and its strong commitment to health, social service, and other assistance 

programs. Health and social-service programs have attempted to meet the needs of alcohol- and drugrelated problems by providing treatment programs and shelters for wives and families of abusive spouses 

and by placing greater emphasis on recreational programs and services. However, in comments before the 

Department of the Interior’s OCS Policy Committee’s May 2000 meeting, NSB Mayor George Ahmaogak 

stated that Borough residents are extremely concerned that a lack of adequate financing for local NSB city 

governments has hampered the development of these programs, and declining revenues from the State of 

Alaska have seriously impaired the overall function of these city governments. Partnering together, Tribal 

governments, city governments, and the NSB government have been able to provide some programs, 

services, and benefits to local residents. For several years, all communities in the Borough have banned the 

sale of alcohol, although alcohol possession is not banned in Barrow, and many communities are 

continually under pressure to bring the issue up in local referendums (North Slope Borough, 1998). Effects 

on social health in Nuiqsut would have direct consequences on sociocultural systems but would not tend 

toward the displacement of existing systems above the displacement that has already occurred with the 

current level of development. 

Stress created by the fear that oil exploration, development, and production (and anticipated oil spills) will 

soon follow the seismic surveys is a distinct predevelopment impact-producing agent. Stress from this 

general fear can be broken down into the particular fears of: 

• being inundated during cleanup with outsiders who could disrupt local cultural continuity; 

• the damage that spills would do to the present and future natural environment; 

• drawn out oil-spill litigation; 

• contamination of subsistence foods; 

• lack of local resources to mobilize for advocacy and activism with regional, State, and Federal 

agencies; 

• lack of personal and professional time to interact with regional, State, and Federal agencies; 

• retracing the steps (and the frustrations involved) taken to oppose offshore development; 

• responding repeatedly to questions and information requests posed by researchers and regional, 

State, and Federal outreach staff; and 

• having to employ and work with lawyers to draft litigation in attempts to stop proposed 

development. 

III.G.3.c(4) Alaska Native Views. North Slope Inupiat continue to express concern about the differences 

in how they and the dominant culture relate to the land and waters. Rex Okakok from Barrow expressed 

the problem when he said, “Our land and sea are still considered and thought by outsiders to be the source 

of wealth, a military arena, a scientific laboratory, or a source of wilderness to be preserved, rather than as a 

homeland of our Inupiat” (USDOI, MMS, 1987b). Considering such use of Inupiat territory, Robert 

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Edwardson from Barrow said that he would like to see revenues paid to the Inupiat for mineral rights 

(USDOI, MMS, 1995a; USDOI, MMS, 2003a). 

At hearings in 1982, Mark Ahmakak from Nuiqsut stated that there should be economic benefits to 

Nuiqsut, such as cheaper diesel, from any oil and gas development activities in the Beaufort and Chukchi 

seas (Ahmakak, 1982, as cited in USDOI, MMS, 1982). The consensus is that some benefit should come to 

the community from nearby oil activities. Nuiqsut resident Joseph Ericklook expressed the community’s 

wish to see employment opportunities for local people result from development (Ericklook, 1990, as cited 

in USDOI, MMS, 1990d). In a 1996 public meeting for the Northstar Project, a Nuiqsut elder stated that 

she wanted potential human-health issues that could result from the project looked into beforehand. These 

issues could be found in information from other projects. She specifically expressed concern about 

cancers, health problems related to air pollution, and shortened lifespans (Dames and Moore, 1996). 

As early as 1983, Nuiqsut residents asked to be part of industry activities in the region. Mark Ahmakak 

stated: “I think that if you are going to go ahead with this sale that you should utilize Natives in the areas 

affected by this lease sale; then utilize some of these Natives as monitors on some of your projects” 

(Ahmakak, 1983, as cited in USDOI, MMS, 1983). Mayor Lon Sonsalla of Kaktovik believes that to keep 

up with development activities, the village needs an impact office there to review EIS documents and 

monitor offshore activities (Sonsalla, 1996, as cited in USDOI, MMS, 1996a). 

III.G.3.c(5) Conclusions. Effects on the sociocultural systems of the communities of Kaktovik, Nuiqsut, 

Barrow, Atqasuk, Wainwright, Point Lay, and Point Hope might result from seismic-exploration activities. 

Because the seismic-survey activities are vessel based, stresses to local village infrastructure, health care, 

and emergency response systems are expected to be minimal; therefore, social systems in these 

communities would experience little direct disturbance from the staging of people and equipment for 

seismic exploration. However, the possible long-term deflection of whale migratory routes or increased 

skittishness of whales due to seismic-survey activities in the Beaufort and Chukchi seas might make 

subsistence harvests more difficult, dangerous, and expensive. To date, no long-term deflections of 

bowheads have been demonstrated; however, seismic activity of the magnitude discussed in the scenario 

for this PEA has not been approached since the 1980’s. 

The more predominant issue associated with potential impacts on sociocultural systems is the potential 

disruption of seismic survey noise on subsistence-harvest patterns particularly on the bowhead whale, 

which is a pivotal species to the Inupiat culture. Such disruptions could impact sharing networks, 

subsistence task groups, and crew structures as well as cause disruptions of the central Inupiat cultural 

value: subsistence as a way of life. These disruptions also could cause a breakdown in family ties, the 

community’s sense of well-being, and could damage sharing linkages with other communities. 

Displacement of ongoing sociocultural systems by seriously curtailing community activities and traditional 

practices for harvesting, sharing, and processing subsistence resources might occur. 

III.G.3.d. Impacts of Alternatives on Socioculture. 

III.G.3.d(1) Alternative 1 (No Action). The MMS would not approve seismic-survey permit applications 

for the purpose of obtaining geophysical information about the location, extent, and properties of 

hydrocarbon resources in the Chukchi and Beaufort seas. Industry would have to rely on other measures to 

obtain needed geophysical information, such as using new data-processing technology to reanalyze existing 

geophysical exploration seismic data and/or using other survey techniques, other than seismic. Because no 

seismic-survey activity would occur, no impacts to subsistence resources and practices and consequent 

impacts on sociocultural systems would be expected. However, if other nonseismic field techniques are 

proposed to be used, they would require additional environmental analysis. 

III.G.3.d(2) Alternatives 3, 4, 5, and 6. Seismic surveys for geophysical exploration activities in each 

alternative would be permitted with existing Alaska OCS exploration stipulations and guidelines and 

additional specific protective measures, including a specified isopleth-exclusion zone (either 120 dB, 160 

dB, 120 dB and 160 dB, or 180/190 dB). Additional protective measures (beyond the existing Alaska OCS 

exploration stipulations and guidelines) would be identified and incorporated into this alternative to ensure 

 PEA-185 
that fish, wildlife, and subsistence-harvest resources and practices are not adversely impacted. An inability 

to effectively perform mitigation measures will result in the suspension of a G&G permit until such time 

that the protective measures can be successfully performed and demonstrated. 

Avoidance planning, stipulations and required mitigation, and conflict avoidance measures under MMPA 

authorization are defined by NMFS and FWS (identified in the subsistence discussion for Alternative 3) 

and made a part of each alternative would serve collectively to mitigate disturbance effects on Native 

lifestyles and subsistence practices and would likely mitigate any consequent impacts on sociocultural 

systems. 

To ensure compliance with the MMPA, MMS also is requiring seismic-survey operators to obtain from 

NMFS and FWS an Incidental Take Authorization (ITA), which could be in the form of an IHA or LOA, 

before commencing MMS-permitted seismic-survey activities. The ITA’s mitigation and monitoring 

requirements would further ensure that impacts to marine mammals will be negligible and that there will 

be no unmitigable adverse impact on subsistence uses of marine mammals. 

To achieve this standard, the seismic operators are negotiating a CAA with the AEWC and the affected 

villages’ Whaling Captains Association. The CAA likely will include a prohibition on conducting seismic 

surveys during the bowhead whale-hunting season in the Beaufort Sea, describe a dispute-resolution 

process, and provide emergency assistance to whalers at sea. Implementation of the CAA further ensures 

that there will not be significant social or economic impacts on the coastal inhabitants of the Beaufort and 

Chukchi seas by avoiding an adverse impact on subsistence marine mammal-harvest activities. 

III.G.4. Archaeological Resources. 

III.G.4.a. Overview. “Archaeological Resources” can be defined as “any prehistoric or historic district, 

site, building, structure, or object [including shipwrecks]...including artifacts, records, and remains which 

are related to such a district, site, building, structure, or object” (National Historic Preservation Act, Sec. 

301 as amended, 16 U.S.C. 470). Significant archaeological resources are either historic or prehistoric and 

generally include properties of >50 years that: (1) are associated with events that have made a significant 

contribution to the broad patterns of our history; (2) are associated with the lives of persons significant in 

the past; (3) embody the distinctive characteristics of a type, period, or method of construction; (4) 

represent the work of a master; (5) possess high artistic values; (6) present a significant and distinguishable 

entity whose components may lack individual distinction; or (7) have yielded, or may be likely to yield, 

information important in history. These resources also represent the remains of the material culture of past 

generations of the region’s prehistoric and historic inhabitants. They are basic to our understanding of the 

knowledge, beliefs, art, customs, property systems, and other aspects of the nonmaterial culture. 

The two locational categories and the two time sequences of archaeological resources applicable to the 

proposed seismic survey action are respectively, offshore/onshore and prehistoric/historic. 

III.G.4.b. Offshore Prehistoric Resources. At the height of the late Wisconsinan glacial advance 

(approximately 19,000 years ago), global (eustatic) sea level was approximately 120 m lower than present. 

During this time, large expanses of what is now the OCS were exposed as dry land. The exact elevation of 

past sea levels in relation to present sea level varies geographically, depending primarily on the location of 

the area in relation to the major late-Wisconsinan ice masses. This is referred to as relative sea level. 

There are no good relative sea-level data for the major portion of the Alaska OCS; however, relict fluvial 

channels and shoreline features evident at the seafloor suggest that sea level was probably between 50 and 

60 m lower than present at 12,000 B.P. (Before Present) (Dixon, Sharma, and Stoker, 1986). Therefore, a 

conservative estimate of 60 m below present is used for relative sea level at 12,000 B.P., the date at which 

prehistoric human populations could have been present in the area. The location of the 12,000-B.P. 

shoreline is roughly approximated by the 60-m bathymetric contour. The continental shelf shoreward of 

this contour would have potential for prehistoric sites dating subsequent to about 12,000 B.P. 

 PEA-186 
Seismic-survey and borehole data that have been collected in the Beaufort and Chukchi seas indicate areas 

of well-preserved Holocene sedimentary sequences and landforms that have potential for containing 

prehistoric archaeological deposits. In the Beaufort Sea, remote-sensing data from the Liberty, Warthog, 

and McCovey prospects, landward of the barrier islands, indicate little evidence of ice gouging at the 

seafloor and areas of well-preserved landforms, such as river channels with levees and terraces just below 

the seafloor. Although these features have not been directly dated, their stratigraphic position indicates that 

they are most likely Holocene in age. The presence of these preserved landforms just beneath the seafloor 

indicates that there also is potential for preservation of prehistoric archaeological sites that may occur in 

association with the landforms. However, the potential for the occurrence of archaeological resources in 

the Beaufort Sea seaward of the barrier islands probably is much lower than for those areas landward of the 

barrier islands and in areas protected by floating, landfast ice during the winter. 

Analyses of shallow geologic cores obtained by the U.S. Geological Survey in the northeastern Chukchi 

Sea indicate the presence of well-preserved coastal plain sedimentary sequences of Holocene age just 

beneath the seafloor (R.L. Phillips, written commun., USGS, Menlo Park, California, April 18, 1991). 

Radiocarbon dates on in situ freshwater peat contained within these deposits indicate that relative sea level 

in the Chukchi Sea area would have been approximately 50 m below present at 11,300 B.P., the 

approximate date of the earliest known prehistoric human populations in the area. The location of the 

11,300-B.P. shoreline is roughly approximated by the 50-m bathymetric contour. The continental shelf 

shoreward of this contour would have potential for prehistoric sites dating subsequent to approximately 

11,300 B.P. The presence of preserved nonmarine Holocene sedimentary sequences in the Chukchi Sea 

indicates that there also is potential for preservation of prehistoric archaeological sites. Even in some areas 

of intense ice gouging, such as off Icy Cape, the Holocene sediments are thick enough that any 

archaeological sites that occurred in the underlying Late Pleistocene deposits would be below the depth 

affected by ice gouging (USDOI, MMS, 1990c). 

III.G.4.c. Offshore Historic Resources. Between 1851 and 1934, 34 shipwrecks occurred within a few 

miles of Barrow; another 13 wrecks occurred to the west and east of Barrow in the waters of the Chukchi 

and Beaufort seas. No surveys of these shipwrecks have been made; therefore, no exact locations are 

known. These wrecks would be valuable finds, providing us with information on past cultural norms and 

practices, particularly with regard to the whaling industry (Tornfelt and Burwell, 1992). 

At Point Belcher near Wainwright, 30 ships were frozen in the ice in September 1871; 13 others were lost 

in other incidents off Icy Cape and Point Franklin. Another 7 wrecks occurred off Cape Lisburne and Point 

Hope. From 1865-1876, 76 whaling vessels—an average of more than 6 per year—were lost because of ice 

and also because of raids by the Shenandoah, which burned 21 whaling ships near the Bering Strait during 

the Civil War (Bockstoce, 1977). The possibility exists that some of these shipwrecks have not been 

completely destroyed by ice and storms. The probabilities for preservation are particularly high around 

Point Franklin, Point Belcher, and Point Hope (Tornfelt and Burwell, 1992). 

A recent remote-sensing survey in the Beaufort Sea recorded a large side-scan sonar target. The size and 

shape of this object and historical accounts suggest that it may be the crash site of the Sigismund 

Levanevsky, a Russian airplane that was lost during a transpolar flight in 1939 (Rozell, 2000). Subsequent 

attempts at ground-truthing this object has been unsuccessful in relocating the object and confirming its 

identity. 

III.G.4.d. Onshore Prehistoric and Historic Resources. Onshore archaeological resources near the 

Chukchi Sea coast receive less damage from the eroding shoreline than those on the Beaufort Sea coast, 

which is subjected to more slumping because of water action and permafrost (Lewbel, 1984). Therefore, 

known onshore archaeological resources exist in greater numbers in the Chukchi Sea area; also, unknown 

resources are more likely to exist. There are 200-300 known archaeological sites in the Hope Basin area, 

and the area around Point Hope is especially rich in archaeological resources. Many of the known sites are 

of Kukmiut and Inupiat tradition and include villages, graves, whaling camps, and fishing/hunting camps. 

The Alaska Heritage Resources Survey (AHRS) keeps a database of all known archaeological sites, 

including those on the National Historic Register. A review of the AHRS site files indicates that 18 sites 

 PEA-187 
with prehistoric components have been recorded in areas adjacent to the Beaufort Sea. They are comprised 

of habitation sites, lithic scatters, and isolated finds. 

III.G.4.e. Impact Assessment. Alternatives 3 through 6 includes potential use of OBC surveys to gather 

seismic data. The OBC surveys could be used in the Beaufort Sea Planning Area to acquire seismic-survey 

data in water that is too shallow (14 m or shallower) for the data to be acquired using marine streamers and 

too deep to have bottomfast ice in the winter, which would allow over-ice winter operations. It is possible 

that cables would be laid in water deeper than 14 m, if the deeper water data was part of a larger acquisition 

program that went from shallow to deeper water. The OBC surveys require the use of multiple ships 

(usually two ships for cable layout/pickup, one for recording, one for shooting, and two smaller utility 

boats). These vessels are generally smaller than those used in streamer operations, and the utility boats are 

quite small. 

Operations begin by dropping cables off the back of the layout boat. Cable length is typically 4,200 m but 

can be up to 12 km. Groups of seismic detectors (usually hydrophones and vertical motion geophones) are 

attached to the cable in intervals of 25-50 m. Multiple cables are laid on the seafloor parallel to each other 

using this layout method, with a 50- to 100-m interval between cables. When the cable is in place, a ship 

towing a dual airgun array passes between the cables, firing every 25 m. Sometimes a faster source ship 

speed of 6 kn instead of the normal 4.5-kn speed is used, with an increase in time between airgun firings. 

After a source line is shot, the source ship takes about 10-15 minutes to turn around and pass down between 

the next two cables. When a cable is no longer needed to record seismic data, it is retrieved by the cablepickup ship and moved to the next recording position. A particular cable can lay on the bottom anywhere 

from 2 hours to several days, depending on operation conditions. Normally, a cable is left in place about 

24 hours; however, cables left on the bottom during storms sometimes can work into the substrate before 

they can be recovered. The OBC surveys might occur in the Beaufort Sea but are not anticipated to occur 

in the Chukchi OCS because of its great water depths and the greater efficiency of streamer operations in 

deep water. 

The OBC seismic surveys potentially could impact both prehistoric and historic archaeological resources in 

waters inshore of the 20-m isobath or in deeper water, if cables are laid from shallow to deep water as part 

of one program. Activities associated with such offshore seismic-exploration activities projected for the 

2006 open-water season could disturb these resources and their in situ context. Assuming compliance with 

existing Federal, State, and local archaeological regulations and policies and the application of MMS’ 

G&G Permit Stipulation 6 (regarding the discovery of archaeological resources) and CFR 251.6 (a)(5) 

regarding G&G Explorations of the Outer Continental Shelf to not “disturb archaeological resources,” most 

impacts to archaeological resources in shallow offshore waters of the Beaufort Sea Planning Area would be 

avoided. Therefore, no impacts or only minor impacts to archaeological resources are anticipated. 

III.G.5. Land Use Plans and Coastal Zone Management. 

III.G.5.a. Land Status and Use. The Federal Government is the sole owner of the Chukchi and Beaufort 

Sea OCS, but the adjacent nearshore and onshore areas is a mix of landholders. With the exception of the 

tidelands offshore of the Arctic National Wildlife Refuge (ANWR), the State of Alaska owns all 

submerged lands along the coast out to 3 nmi. The adjacent onshore area is within the NSB, and most land 

within the NSB is held by a few major landowners. The predominant landowner within the NSB is the 

Federal Government, which owns the NPR-A ANWR. Other major landholders include the State of 

Alaska, eight Native village corporations, and the Arctic Slope Regional Corporation. 

Documents addressing land use in the NSB include the NSB Comprehensive Plan and Land Management 

Regulations (NSBCP&LMR), and the NSB Coastal Management Program (NSBCMP). Major land uses 

and offshore areas on the North Slope are divided between traditional subsistence uses of the land, 

community development, and hydrocarbon-development operations. Along the Chukchi Sea coast, 

traditional settlement patterns and subsistence uses of land prevail. 

 PEA-188 
The NSBCP&LMR is intended to guide decisions affecting land use, transportation, fire protection, public 

facilities, and the economy. The major goal is to support development of the villages and natural resources 

in a way that preserves the Inupiat way of life. Offshore policies are specifically limited to development 

and uses in the portion of the Beaufort and Chukchi seas that are within the boundary of the NSB. 

Activities on the OCS would not be subject to the NSBCP&LMR. 

III.G.5.b. Coastal Zone Management. Through the Federal Coastal Zone Management Act and the 

Alaska Coastal Management Act (ACMA), development and land use in coastal areas are managed to 

provide a balance between the use of coastal areas and the protection of valuable coastal resources. Alaska 

recently amended its coastal management program (ACMP) and adopted new standards under 11 AAC 

110, 112, and 114. The National Oceanic and Atmospheric Administration (NOAA), Office of Ocean and 

Coastal Resource Management (OCRM), reviewed the amended the ACMP, completed a full NEPA 

analysis, and approved Alaska’s revised program on December 29, 2005. 

The process for determining consistency for activities requiring a Federal permit is governed by 15 CFR 

930, Subpart D. Under the subpart, a State is directed to develop a list of specific Federal licenses or 

permit activities that it wishes to review for consistency with its management program (15 CFR 930.53). 

Alaska’s list of Federal licenses and permits that are subject to consistency review is found in 11 AAC 

110.400. Geophysical exploration permits issued by MMS are not included on the list. Consequently, a 

consistency review under ACMP is not required for these permits. Should the State of Alaska desire to 

review permits issued by MMS for geophysical exploration in the Chukchi and Beaufort seas, it would 

need to obtain approval to review the unlisted activity from OCRM. 

III.G.6. Environmental Justice. 

III.G.6.a. Overview. Environmental Justice is an initiative that culminated with President Clinton’s 

February 11, 1994, Executive Order 12898, “Federal Actions to Address Environmental Justice in Minority 

Populations and Low-Income Populations,” and an accompanying Presidential memorandum. The 

Executive Order requires each Federal Agency to make the consideration of Environmental Justice part of 

its mission. Its intent is to promote fair treatment of people of all races, so no person or group of people 

shoulders a disproportionate share of the negative environmental effects from this country’s domestic and 

foreign programs. It focuses on minority and low-income people, but the Environmental Protection 

Agency (USEPA) defines environmental justice as the “equal treatment of all individuals, groups or 

communities regardless of race, ethnicity, or economic status from environmental hazards” (U.S. 

Department of Energy, 1997; USEPA, 2006). Specifically, the Executive Order requires an evaluation as 

to whether the proposed project would have “disproportionately high adverse human health and 

environmental effects...on minority populations and low income populations.” The Environmental Justice 

Executive Order also includes consideration of potential effects to Native subsistence activities and, to this 

end, MMS continues to maintain a dialogue on Environmental Justice with local communities in this 

region. 

Since 1999, all MMS public meetings have been conducted under the auspices of Environmental Justice. 

Environmental Justice-related concerns are taken back to MMS management and incorporated into 

environmental study planning and design, environmental impact evaluation, and the development of 

mitigating measures. 

Executive Order 13175, “Consultation and Coordination with Indian Tribal Governments,” requires Federal 

agencies to consult with tribal governments on Federal matters that significantly or uniquely affect their 

communities. In January 2001, a USDOI Alaska Regional Government-to-Government policy was signed 

by all the USDOI Alaska Regional Directors, including the MMS. In acknowledgement of the importance 

of consultation, the MMS invites tribal governments to participate in its environmental assessment 

processes. 

The Inupiat People of the North Slope and the Northwest Arctic boroughs have made MMS aware of the 

potential burden of participating in too many planning and public meetings. Therefore, MMS has taken 

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measures to more carefully plan the number and timing of meetings with regional tribal groups and local 

governments. 

III.G.6.b. Demographics. 

III.G.6.b(1) Race. Alaska Inupiat Natives, a recognized minority, are the predominant residents of the 

NSB and Northwest Arctic Borough, which make up the Alaska regional governments in the action area. 

The 2000 Census counted 7,385 persons resident in the North Slope Borough; 5,050 identified themselves 

as American Indian and Alaskan Native for a 68.38% indigenous population. In the Northwest Arctic 

Borough, the 2000 Census counted 7,288 persons, 5,944 identified themselves as American Indian and 

Alaskan Native for an 82.5% indigenous population (USDOC, Bureau of the Census, 2000). 

Inupiat Natives are the only minority population allowed to conduct subsistence hunts for marine mammals 

in the region and, in potentially affected Inupiat communities, there are no significant numbers of “other 

minorities.” Additionally, “other minorities” would not be allowed to participate in subsistence marine 

mammal hunts and, therefore, would not constitute a potentially affected minority population (North Slope 

Borough, 1999). 

Because of the homogeneous Inupiat population of the NSB and Northwest Arctic Borough, it is not 

possible to identify a “reference” or “control” group within the potentially affected geographic area, for 

purposes of analytical comparison, to determine if the Inupiat are affected disproportionately. This is 

because a non-minority group does not exist in a geographically dispersed pattern along the potentially 

affected area of the North Slope and Northwest Arctic Boroughs. Population counts from the 2000 Census 

for Native subsistence-based communities in the region and their total American Indian and Alaskan Native 

population percentages can be seen in Table III.G.1. 

III.G.6.b(2) Income. The U.S. average median household income in 2000 was $42,148, and the U.S. 

average per-capita income was $29,469. The Alaskan average median household income in 2000 was 

$50,746, and the Alaska average per-capita income was $29,642. The average NSB median household 

income ($63,173) was above State and national averages, but the average per-capita income ($20,540) was 

below the State and national averages. The median household incomes in all subsistence-based 

communities in the Borough were above State averages except Nuiqsut ($48,036), and all were above 

national averages. Per capita incomes in all these communities were below State and national averages. 

The average Northwest Arctic Borough median household income ($45,976) was below the State average 

but above the national average, but the average per-capita income ($15,286) was below State and national 

averages. The median household incomes of the subsistence-based communities of Kivalina ($30,833), 

Buckland ($38,333), and Deering ($33,333) were below State and national averages, and those for 

Kotzebue ($57,163) and Noorvik ($51,964) were above. Per capita incomes in all these communities were 

below State and national averages. 

The thresholds for low income in the region were household incomes below $57,500 in the NSB and 

$54,550 in the Northwest Arctic Borough. Poverty-level thresholds were based on the U.S. Census Bureau, 

Census 2000 Survey; low income is defined by the U.S. Census Bureau as 125% of poverty level. 

Subsistence-based communities in the region qualify for Environmental Justice analysis based on their 

racial/ethnic minority definitions alone. Nevertheless, the figures indicate that low income commonly also 

correlates with Native subsistence-based communities in the region (USDOC, Bureau of the Census, 2000, 

2002). The 2000 Census “Tiger” files ( files from the U.S. Census’ Topologically Integrated Geographic 

Encoding and Referencing [TIGER] database) identify no nonsubsistence-based coastal communities in the 

North Slope and Northwest Arctic boroughs with median incomes that fall below the poverty threshold. 

The median household, median family, and per capita incomes; the number of people in poverty and the 

percent of the total Borough or Native subsistence-based community population are shown in Table III.G.2. 

III.G.6.b(3) Consumption of Fish and Game. As defined by the NSB Municipal Code, subsistence is “an 

activity performed in support of the basic beliefs and nutritional need of the residents of the borough and 

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includes hunting, whaling, fishing, trapping, camping, food gathering, and other traditional and cultural 

activities” (State of Alaska, DNR, 1997). This definition gives only a glimpse of the importance of the 

practice of the subsistence way of life in Inupiat culture, but it does underscore that it is a primary cultural 

and nutritional activity on which Native residents of the North Slope depend. For a more complete 

discussion of subsistence and its cultural and nutritional importance, see section III.G.2 (Subsistence 

Environment). 

III.G. 6.c. Impact Assessment Overview. Seismic surveys, with very little anticipated onshore support 

activities, might affect coastal communities. Most Alaskan coastal communities are rural and 

predominantly Native (a defined ethnic minority), and many contain at least subpopulations with low 

incomes. Therefore, specific local minority (and possibly poor [low-income]) populations are present that 

could be potentially affected by the proposed seismic survey activities. For these reasons, the MMS 

socioeconomics studies agenda has emphasized the documentation of subsistence uses, and the potential 

impacts of OCS activities on such uses, along with the more general characterization of rural (Native and 

non-Native) social organization and the incorporation of local and traditional knowledge. The MMSsponsored studies have focused most heavily on communities on the North Slope (the area of most onshore 

and offshore oil and gas activity) and MMS has funded projects to synthesize local and traditional 

knowledge. The MMS has recognized the extreme importance of whales and whaling to the North Slope 

communities, and has conducted a bowhead whale aerial survey annually since 1987. A newly-funded 

MMS study, “Quantitative Description of Potential Impacts of OCS Activities on Bowhead Whale Hunting 

and Subsistence Activities in the Beaufort Sea,” is ongoing. 

Perhaps more importantly, MMS has recognized the importance of local consultation, and the important 

role that the NSB and other local organizations and institutions can play in the development and evaluation 

of specific actions. Such a consultation process will also be a part of all actions addressed in this PEA. 

Although MMS has amassed an astounding body of public testimony—much of it from Alaskan Natives—

as a result of the public hearing process, the agency’s consultation process extends far beyond these formal 

hearings. The MMS now routinely includes Native representation on the Scientific Review Boards for its 

major projects, and tries to conduct at least occasional Information Transfer Meetings (discussing the 

findings of recently concluded and ongoing studies and proposed efforts) near those communities most 

likely to be affected. Major concerns expressed at public meetings included: 

• Identifying and protecting important subsistence areas (all 6 communities) 

• Restricting access to subsistence areas and resources (5 communities) 

• Studying and maintaining the health of wildlife (3 communities) 

• Providing natural gas to local communities (3 communities) 

• Studying caribou and fish (3 communities) 

• Mitigating seismic disturbance of caribou, fish, and whales (3 communities) 

• Making better use of traditional knowledge (3 communities); 

• Providing more local hire (3 communities) 

• Updating outdated resource data (2 communities) 

• Involving local people in scientific studies of resources (2 communities) 

• Including local people in the planning process (2 communities) 

Many of these issues are discussed in government-to-government consultation with tribes and the Inupiat 

Community of the Arctic Slope and in meetings with the NSB and the AEWC. 

The MMS conducted outreach meetings under the auspices of Environmental Justice from January through 

March 2006 with regional and local governments and tribes in Point Hope, Point Lay, Wainwright, Barrow, 

Nuiqsut, and Kaktovik to consult on current stakeholder concerns and issues with regard to upcoming 

offshore exploration and leasing in the region, and specifically concerning seismic activities planned for the 

2006 open-water season. 

One overarching way MMS has tried to address Native concerns has been to include local Inupiat 

traditional knowledge in its environmental assessments and environmental impact statements. 

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In summary, Alaskan Inupiat Natives, a recognized minority, are the predominant residents of the 

communities of Kaktovik, Nuiqsut, Barrow, Atqasuk, Wainwright, Point Lay, Point Hope, and Kivalina, 

the areas potentially most affected by activities assessed in this PEA. Effects on Inupiat Natives might 

occur because of their reliance on subsistence foods, and noise from seismic survey activities may affect 

subsistence resources and harvest practices. “Significant” effects on environmental justice is defined as: 

disproportionately high adverse impacts to low-income and minority populations. Potential significant 

impacts to subsistence resources and harvests and consequent impacts to sociocultural systems could result 

in adverse environmental justice impacts. However, potential adverse affects are expected to be mitigated 

substantially, though not eliminated. Furthermore, potential long-term impacts on human health from 

contaminants in subsistence foods and climate change effects on subsistence resources and practices would 

be expected to exacerbate overall potential effects on low-income, minority populations. 

III.G.6.d. Impacts of Alternatives. 

III.G.6.d(1) Alternative 1. The MMS would not approve seismic survey permit applications for the 

purpose of obtaining geophysical information about the location, extent, and properties of hydrocarbon 

resources in the Chukchi and Beaufort seas. Industry would have to rely on other measures to obtain 

needed geophysical information, such as using new data processing technology to reanalyze existing 

geophysical exploration seismic data and/or using other survey techniques, other than seismic. Because no 

seismic survey activity would occur, no environmental justice impacts would be expected. 

III.G.6.d(2) Alternatives 3, 4, 5, and 6. Seismic surveys for prelease geophysical exploration activities 

would be permitted with existing Alaska OCS exploration stipulations and guidelines and additional 

specific protective measures, including a specified isopleth-exclusion zone (120 dB, 160 dB, 120 dB and 

160 dB, or 180/190 dB). Additional protective measures (beyond the existing Alaska OCS exploration 

stipulations and guidelines) would be identified and incorporated into each of these alternative to ensure 

that fish, wildlife, and subsistence-harvest resources and practices are not adversely impacted. An inability 

to effectively perform mitigation measures will result in the suspension of a G&G permit until such time 

that the protective measures can be successfully performed and demonstrated. 

Inupiat Natives could be disproportionately affected by any alternative that allows seismic because of their 

reliance on subsistence foods; and actions under these alternatives could affect subsistence resources and 

harvest practices. Avoidance planning, stipulations and required mitigation, and conflict avoidance 

measures under IHA requirements as defined by NMFS and FWS (identified in Section III.G.2, the 

Subsistence Environment discussion for Alternative 3) and made a part of each alternative would serve 

collectively to mitigate disturbance effects on environmental justice. Mitigating measures likely would 

incorporate traditional knowledge and the cooperative efforts between MMS, the State, the people of the 

North Slope, and tribal and local governments. With required mitigation and conflict avoidance measures 

in place, significant impacts to subsistence resources and hunts would not occur as a result of this action, 

thereby avoiding significant impacts on sociocultural systems and disproportionately high adverse impacts 

on low income and minority populations in the region—significant environmental justice impacts. 

III.G.6.d(3) Standard, Potential, and Ongoing Studies and Mitigation Initiatives. Avoidance planning, 

stipulations and required mitigation, and conflict avoidance measures under IHA requirements as defined 

by NMFS and FWS, the employment of Inupiat observers onboard seismic-survey vessels, and the 

additional noise and disturbance mitigation discussed in the subsistence-harvest discussion for Alternative 

3 (Section III.G.2, Subsistence Environment) would serve collectively to mitigate disturbance effects on 

environmental justice. 

The Alaska OCS Region promotes studies that directly address the standing issues and concerns of Native 

stakeholders. The MMS involves local and tribal governments in its studies planning process and has held 

meetings in all local communities to assist their involvement in this effort. The MMS’ participation in the 

newly formed North Slope Science Initiative ensures MMS’ continued involvement in slopewide scientific 

research formulation and coordination. 

 PEA-192 
Particular studies that the MMS has funded to address sociocultural and environmental justice impacts 

include: the MMS’ Bowhead Whale Feeding Study, conducted out of the village of Kaktovik, that includes 

local Inupiat in the study design, data gathering, and data analysis; the Arctic Nearshore Impact Monitoring 

In Development Areas (ANIMIDA) study (designed specifically to meet requests from the Inupiat 

community) and its followup study, Continuation of Arctic Nearshore Impact Monitoring in Development 

(CANIMIDA); the Quantitative Description of Potential Effects of OCS Activities on Bowhead Whale 

Hunting/Subsistence Activities in the Beaufort Sea study; the Alaska Marine Mammal Tissue Archival 

Project, the Subsistence Mapping of Nuiqsut, Kaktovik, and Barrow: Past and Present Comparison study; 

and the North Slope Borough Economy, 1965 to Present study. 

One study that particularly tried to address seismic effects was the GIS Geospatial Database of OilIndustry and Other Human Activity (1979-1999) in the Alaskan Beaufort Sea, completed in 2002. This 

study was initiated to compile detailed information describing the locations, timing, and nature of oil and 

gas related and other human activities in the Alaskan Beaufort Sea. An important objective of the database 

was to assess concerns expressed by subsistence hunters and others living within the coastal villages of the 

Beaufort Sea about the possible effects that oil and gas activities (particularly seismic activity, drilling, and 

oil and gas support-vessel activities) had on the behavior of marine mammals, especially the bowhead 

whale. The Human Activities Database, however, is proprietary because it includes sensitive oil and gas 

industry data. With the exception of ice-management activity, the compiled information for the period 

1990-1998 is relatively complete and considered adequate for the investigation of potential effects of 

disturbance on the fall bowhead whale migration. However, there are significant gaps in the data for the 

period 1979-1989. This initiative continues under the ongoing study Analysis of Covariance of Human 

Activities and Sea ice in Relation to Fall Migrations of Bowhead Whales. 

Newly funded MMS studies that address sociocultural and environmental justice impacts include: (1) 

Dynamics of Distribution and Consumption of Subsistence Resources in Coastal Alaska; (2) Researching 

Technical Dialogue with Alaskan Coastal Communities: Analysis of the Social, Cultural, Linguistic, and 

Institutional Parameters of Public/Agency Communication Patterns; (3) Analysis of Variation in 

Abundance of Arctic Cisco in the Colville River (this study has a Traditional knowledge component); (4) 

Monitoring the Distribution of Arctic Whales; (5) Bowhead Whale Feeding in the Central and Western 

Alaska Beaufort Sea; (6) Aerial Photography of Bowhead Whales to Estimate the Size of the Western 

Arctic Population; (7) Satellite Tracking of Eastern Chukchi Sea Beluga Whales in the Beaufort Sea and 

Arctic Ocean; and (8) Development of Remote Sensing Survey techniques for Arctic Marine Mammals: 

Pacific Walrus.

Other initiatives include an MMS-sponsored Information Transfer Meeting (ITM) in Anchorage in January 

1999 and the Beaufort Sea Information Update Meeting in Barrow in March 2000, which presented updates 

on research and studies being conducted in the Beaufort Sea. The March 1999 meeting included 

presentations by Barrow, Nuiqsut, and Kaktovik whaling captains. In early 2005, MMS held an ITM in 

Anchorage, a mini-ITM in Barrow. In October 2005, MMS held a Chukchi Sea Science Update Meeting in 

Anchorage to update its analysts on the current information base and conditions for oceanography and 

marine mammal, fish, bird, subsistence, and sociocultural resources. The meeting’s other purpose was to 

develop a studies regime for these resources in the region. 

The MMS Alaska OCS Region homepage also maintains an Alaska Native Links page that provides 

information on the MMS traditional knowledge-incorporation process, information on Barrow whaling, and 

MMS assistance with the bowhead whale census, in addition to links to Alaskan Native sites and U.S. 

Government Native-related sites. The MMS Alaska OCS Region’s community liaison, Albert Barros, was 

instrumental in getting an Alaskawide Department of the Interior Memorandum of Understanding (MOU) 

with Alaskan tribes on government-to-government consultation signed by all the Alaska Department of the 

Interior Agency Regional Directors. The MMS signed an MOU with the community of Kaktovik in March 

2005 that specifies consultation procedures with the community, and George Ahmaogak, former Mayor of 

the NSB, is a member of MMS’ OCS Policy Committee. 

Over the 2 decades of MMS involvement in the Arctic, local communities have been very vocal about 

finding a “compensation” source⎯impact assistance, revenue sharing, bonds, or mitigation payments⎯to 

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address impacts from OCS activities. Without congressional authorization, the MMS cannot provide or 

require industry to provide such compensation. Federal Agencies cannot commit to impact assistance, 

because that is a role of Congress and not the Executive Branch. Only Congress can alter the OCS Lands 

Act to include provisions for local impact assistance from MMS revenues or provide the authorization for 

funding such revenues. Nevertheless, in response to this critical concern, Department of the Interior and 

MMS staff have drafted legislative language on this subject in response to Congressional requests. 

Furthermore, the MMS OCS Policy Committee has developed a white paper on impact assistance and 

revenue sharing options and has shared this paper and its findings with concerned policymakers. 

In 2001, Congress appropriated impact-assistance funds for coastal states affected by OCS oil and gas 

production. Nationwide, Congress appropriated $150 million to be allocated among eligible oil- and gasproducing states. Alaska received an appropriation of $12.2 million, $1,939,680 of which went to the NSB, 

and $102,530 went to the Northwest Arctic Borough. The Coastal Impact Assistance Program (CIAP) was 

reauthorized by Congress under the Energy Act of 2005. Under the new CIAP, $250 million for each of 

fiscal years 2007 through 2010 will be disbursed directly to eligible producing states and to qualifying 

counties, parishes and boroughs within those states. Under the new CIAP, states eligible to receive funding 

are Alabama, Alaska, California, Louisiana, Mississippi, and Texas. The CIAP funds will be allocated to 

these states based on the proportion of qualified OCS revenues offshore of the individual state to total 

qualified OCS revenues from all states. Because Alaska currently lacks significant OCS production, its 

contribution to total OCS revenues is much less than the other states. Accordingly, Alaska likely will 

receive the minimum allocation provided under the program, or $2.5 million for each year. Thirty-five 

percent must go to local communities. This amount could rise in the future if Alaska’s OCS revenues 

increase as a result of lease sales, lease rentals, and production.

Twenty-seven percent of all OCS leasing, rental, and royalty receipts, within the first 3 mi of the Alaska 

OCS, go to the State of Alaska. Also, subsistence-impact funds administered by the U.S. Coast Guard 

under the Oil Pollution Act of 1990 would be available, in the unlikely event of an oil spill, to provide for 

subsistence-food losses. 

Since July 2003, MMS and the NSB have been in constant consultation and coordination on a number of 

issues that include conflict avoidance, oil-spill-risk analysis, peer review of scientific studies, disturbance 

effects on subsistence resources, cumulative effects recommendations of the 2003 NRC (2003) Report 

Cumulative Environmental Effects of Oil and Gas Activities on Alaska’s North Slope, bowhead whale 

feeding in the Beaufort Sea, deferral area boundaries, and ways to improve stakeholder communication. 

This ongoing dialogue may result in the development of new mitigation, scientific studies, and avenues of 

cooperation (USDOI, MMS, 2004). 

III.H. Cumulative Impacts Analysis. 

Cumulative impacts can result from individually minor but collectively significant actions taking place over 

time. Cumulative effects are the identifiable present effects of past actions to the extent that they are 

relevant and may have a continuing additive effect to the potential effects of the Proposed Action and its 

alternatives. Cumulative impacts describe the incremental impact from the Proposed Action when added to 

the aggregate effects of past actions together with other current and reasonably foreseeable future actions. 

The Proposed Action is MMS-permitted seismic surveying in the Arctic OCS only during 2006. Therefore, 

this cumulative impacts analysis focuses on the potential incremental cumulative impact of the Proposed 

Action and other activities that are reasonably foreseeable to occur during 2006. Given the growing 

interest of oil and gas companies to explore and develop oil and gas resources on the Arctic Ocean OCS, 

there is the potential that seismic surveys will continue in the Chukchi and Beaufort seas beyond 2006. 

Surveys beyond 2006 are dependent on: (1) the amount of data that is collected in 2006; (2) what the data 

indicate about the subsurface geology; and (3) the results of Beaufort Sea Sale 202 and Chukchi Sea Sale 

193. Table III.C-1 provides information about the potential level and type of seismic-survey activities that 

may occur in the Beaufort and Chukchi seas between 2006 and 2010. Potential seismic-survey activity 

beyond 2006 will be addressed in the draft EIS for the OCS Oil and Gas Leasing Program, 2007 to 2012. 

 PEA-194 
The cumulative analyses acknowledge continuing effects from past activities and potential future additive 

effects from the Proposed Actions, where appropriate. The main agents of the cumulative activity scenario 

are: (1) marine seismic surveys; (2) vessel traffic and movements; (3) aircraft traffic; (4) oil and gas 

exploration and development in Federal and State waters; and (5) miscellaneous activities and factors (see 

Section III.C.). Cumulative effects may arise from single or multiple actions and may result in additive or 

interactive effects. Interactive effects may be either countervailing—where the net adverse cumulative 

effect is less than the sum of the individual effects, or synergistic—where the net adverse cumulative effect 

is greater than the sum of the individual effects. As information is available, we have attempted to consider 

potential effects from the incremental impact of the Proposed Actions when added to other past, present, 

and reasonably foreseeable future actions, regardless of what Federal or non-Federal agency or person 

undertakes such actions. 

III.H.1. Fish/Fishery Resources and Essential Fish Habitat. 

III.H.1.a. OCS Seismic-Survey Activities. Impacts to fish resources from past seismic-survey activity in 

the Chukchi and Beaufort seas (Figures III.C.1-3) were not monitored or studied. We cannot determine 

whether or to what extent past seismic surveys conducted in the Chukchi and Beaufort seas influenced 

results obtained in the fish surveys conducted in the past. 

Impacts to fish, fishery resources, and essential fish habitat (EFH) from seismic surveys are outlined in 

Section III.F.1. Seismic surveys conducted on the OCS beyond 2006 would be anticipated to result in the 

same potential for impacts as outlined in Section III.F.1 and, if impacts were to occur from surveys in 

2007-2010, they potentially would add an incremental degree of adverse but not significant impacts to fish 

resources and EFH. In comparison, over the last few decades the Gulf of Mexico has experienced a much 

higher level of seismic activity on an annual basis than what is projected over the next 4-5 years in the 

Alaskan Arctic. Despite this much higher level of activity in the Gulf of Mexico, no population-level or 

significant impacts to fish resources and EFH have been documented in that region from seismic surveys. 

Although there are different species and environmental conditions in the Alaskan Arctic than in the Gulf of 

Mexico, the types of impacts to fish resources and EFH would be expected to be similar, therefore, making 

a comparison between the two regions possible. 

In the Beaufort Sea OCS, site-clearance surveys in 2006 are projected on up to three oil and gas prospects. 

Figure III.C-4 illustrates the existing locations of MMS OCS leases in the Beaufort Sea. Currently leased 

blocks occur approximately 5 km (3 mi) or more offshore of Dease Inlet and Smith Bay, the Colville River 

around to the Sagavanirktok River; the Canning River Delta; the Hulahula and Okpilak rivers; Kaktovik; 

and Aichilik River. Many of these areas, such as Dease Inlet, Smith Bay, and the Colville and 

Sagavanirktok rivers, are important nursery and critical summer feeding habitat to diadromous and marine 

fishes. Potential impacts from site-clearance surveys in these areas may include: displacement, behavioral 

disturbance and, in some specific cases, mortality, or physiological damage. These impacts could be short 

term or long term. 

III.H.1.b. Seismic-Survey Activities in Alaska State Waters. No seismic surveys are forecast to occur 

in State waters in the Chukchi Sea. One seismic survey in State waters of the Beaufort Sea is forecasted to 

occur in each of the following years: 2006, 2008, and 2010. Effects from seismic surveys in Federal 

waters may be amplified if seismic surveys were to simultaneously occur in close proximity to those 

occurring in State waters. However, companies are expected to maintain the minimum required separation 

because, seismic sound sources operating in close proximity will affect data collection. In addition, three 

surveys in State waters over the next 4 years are projected; these would not be expected to add a significant 

level of activity in the Proposed Action area. 

III.H.1.c. Other Seismic-Survey Activities. The University of Texas at Austin, Institute for Geophysics 

plans to conduct a seismic survey in the western Canada Basin, Chukchi Borderland, and Mendeleev 

Ridge, Arctic Ocean, during the period of approximately July 15 to August 25, 2006. The project will 

include collection of seismic reflection and refraction data as well as sediment coring. An assessment of 

the proposed survey concluded that any injurious effects on fish would be limited to very short distances; 

that adult fish near seismic operations are likely to avoid the sound source, thereby avoiding injury; and 

 PEA-195 
that the proposed seismic program, consisting of one seismic-survey vessel operating well out into the 

western Arctic Ocean, is predicted to have negligible to low adverse physical effects on the various life 

stages of fish and invertebrates encountered during its ~40 day duration and 3,625 km extent (LGL Alaska 

Research Assocs., Inc., 2006). GX Technology Corporation plans a 2D seismic survey in late summer and 

autumn this year in the Mackenzie Delta of the Canadian Beaufort Sea. Potential effects would be similar 

to those described in Section III.F.1.i. 

III.H.1.d. Vessel Traffic and Movements. Vessel traffic introduces noise into the marine environment 

that may disturb fish behavior. Its impact upon fish/fishery resources and EFH may be adverse but is 

regarded as negligible. Vessels may anchor or place other equipment overboard into the sea or on the 

seafloor. Anchoring or overboard equipment may damage fragile biocenoses, such as the Boulder Patch or 

macroalgal beds (described in Section III.F.1.e(1)). The OCS seismic-survey vessel operators are to avoid 

such areas with their equipment and operations. Other vessel operators may or may not avoid the areas, 

although the Boulder Patch is well known and mapped. 

III.H.1.e. Air Traffic. Air traffic is not anticipated to contribute additional impacts to fish/fishery 

resources and EFH. 

III.H.1.f. Oil and Gas Exploration and Development Activities in Federal Waters. Section III.C.4.a 

briefly describes oil and gas development activity on the OCS in the Chukchi and Beaufort seas. 

Information describing the impacts realized by past and present exploration and development activities on 

the Alaskan Arctic OCS is limited for fish resources and EFH. Exploratory drilling typically involves 

introducing additional noise into the marine environment, temporarily increased localized turbidity, and the 

disturbance, fragmentation or destruction of habitats (including EFH) and fish/fishery resources. Drilling 

activity also may lead to direct and indirect mortality of fish resources. Fish/fishery populations readily 

may absorb such mortalities or habitat loss if the respective population is sufficiently abundant and 

widespread, or if the habitat loss is only a small fraction of the available habitat necessary to complete all 

phases of its life history. Exploration drilling also requires additional vessel and traffic. No exploration 

drilling is expected to occur during the period of the Proposed Action seismic surveys. 

III.H.1.g. Oil and Gas Exploration and Development in State Waters. Section III.C.4.b. briefly 

describes oil and gas exploration and development activities in State of Alaska waters of the Chukchi and 

Beaufort seas. Information describing the impacts realized by past and present development activity in 

state waters is unknown for fish resources and EFH. Impacts are generally similar to those described 

above, except the fish assemblages affected by activities in state waters are generally different than those 

assemblages occurring in Federal waters. One important exception is that past developments in state 

waters have relied on the construction of causeways connecting the developments to the mainland. The 

impacts of such causeways are generally regarded as adverse to EFH and some fish/fishery resources, the 

magnitude of which is unknown. 

III.H.1.h. Subsistence-Harvest Activities. Section III.G.2 describes subsistence activities on the North 

Slope. While subsistence-harvest resources may differ from community to community, fishes are among 

the primary resources harvested in the NSB. Moreover, fishes are the second or third most important 

resource after caribou and bowhead whales in some communities. Populations of North Slope villages are 

increasing by as much as 31-119% over the last 30 years (USDOI, BLM, 2005:Table 4-20). The Alaska 

Department of Fish and Game maintains a Subsistence Community Profile Database that shows subsistence 

harvest of fish resources also is increasing over time, indicating that population growth in villages leads to 

more subsistence harvest of fish resources. 

Information is lacking regarding stock estimates of available fish resources used in subsistence harvests. 

Harvesting fish resources removes individuals from the population; hence, it has a negative effect to the 

resource. Many fish populations are capable of a sustainable harvest regime; however, some fish resources, 

such as many rare species, are unsuitable for even moderate-scale harvest practices. 

Given that climate change is occurring in the region and that subarctic and boreal marine and coastal fish 

species, such as Pacific salmon, are expected to expand their distribution and abundance in the Chukchi 

 PEA-196 
(first) and Beaufort (subsequently) seas, the composition of fish resources harvested by North Slope 

villages is likely to change. With the warming climate and change in fish fauna, it is expected that the 

diversity and general biomass of fish resources will increase in the Chukchi and Beaufort seas. These more 

abundant resources may then supplement the trend of population growth in the villages. It is unknown 

whether the increase in fish diversity and biomass as a result of climate change in the region will be 

sufficiently synchronized with the burgeoning populations in the villages; population growth in the villages 

may outpace any increase in fish diversity and biomass in the region, and increased harvest of the resources 

may delay or countervail fish resource population expansions. 

III.H.1.i. Military Activities. Upon occasion, military vessels may transit through the area; no military 

vessels or aircraft are home ported or stationed in the Beaufort and Chukchi seas. Military vessels may 

employ active or passive sonars and echo sounders in their operations that add adverse noise into the 

marine environment as introduced by other anthropogenic sources, such as offshore seismic surveys. 

Active sonar may kill, stun, or displace fish resources in proximity to the source. However, no military 

activities are expected in the Proposed Action area in the foreseeable future. 

III.H.1.j. Industrial Development. Section III.C.5.c describes industrial development on the North 

Slope. Onshore industrial development may adversely affect anadromous streams in the region (i.e., EFH), 

and freshwater and diadromous fish populations. Adverse impacts may include mortality, sublethal harm, 

behavioral disturbances, and habitat fragmentation or loss. Impacts may or may not serve to decrease 

populations in the long term. 

III.H.1.k. Community Development. Section III.C.5.d describes in general the North Slope 

communities, noting that most village populations are increasing. Communities are expected to require 

additional food resources to support burgeoning village populations, and impacts are described above 

relating to the subsistence harvest of fish/fishery resources. Community development projects may be 

beneficial and/or adverse to fish/fishery resources and EFH, depending on the scope of the projects. 

Nearshore development activities in Barrow and Kaktovik include curtailing shoreline erosion. Such 

activities may adversely impact fish/fishery resources and EFH but may benefit fish/fishery resource 

populations in the long term. 

III.H.1.l. Climate Change. The response of fish/fishery resources to past and present climate change in 

the Bering, Chukchi, and Beaufort seas large marine ecosystems (LME’s) are described in detail in 

Sections III.F.1.d and III.F.1.h. The effects of arctic warming appear to already be influencing fish/fishery 

resource populations in the Chukchi and Beaufort seas. 

Information from past surveys indicate some species (e.g., capelin, arctic cisco, arctic cod, arctic staghorn 

sculpin, Pacific sand lance, Bering flounder) exhibit considerable interannual variation in distribution and 

abundance, and that such variation is likely a product of dynamic meteorological and oceanographic 

conditions. We also know that climatic warming has been and continues to influence the Bering, Chukchi, 

and Beaufort seas LME’s. We know that a major ecosystem shift occurred in the southeastern Bering Sea 

in the late 1970’s; that the northern Bering Sea experienced a major ecosystem shift in the last decade or 

more. These major ecosystem shifts are coincident with changes to the distribution and abundance of fish 

resources; and are best explained by climatic warming in the arctic and subarctic regions. We have no 

reason to expect that the fish fauna of the Chukchi and Beaufort seas remained static since they were last 

surveyed; instead, there is good evidence that the fish resources of the Chukchi Sea are adjusting their 

distribution and abundance to the climatic warming occurring there, and that fish resources of the Beaufort 

Sea are adjusting as well, although presumably not as measurably as those fish resources inhabiting the 

Chukchi Sea. 

Climatic warming in the Chukchi and Beaufort seas LME’s, if it continues, is likely to result in impacts, 

potentially significant, to fish/fishery resources and EFH at various points in the future. These likely will 

occur at different intervals depending upon the respective populations. Some fish/fishery resource 

populations will expand their distribution and abundance, while others will contract. The rate at which 

climate change leads to significant impacts to fish/fishery resource populations is variable and uncertain; 

 PEA-197 
however, most of the main agents identified in the cumulative activity scenario may result in population 

reductions and/or habitat degradation or loss. Each year that a population is decreased by one of the main 

agents influences how rapidly that population also responds to climate change. For some fish resource 

populations, the cumulative impacts of the main agents are likely to synergistically interact with climate 

change impacts and accelerate the onset of significant impacts to the population. Ecological theory, 

supported by field studies, indicates that moderate to significant adjustments in one population typically 

produce a cascading effect in the ecosystem whereby competitors, prey, and predator populations also 

adjust. 

Climate change likely will modify habitats (e.g. EFH), making some areas more or less suitable habitat than 

in the past (e.g., spawning habitat for Pacific salmon), depending on the type of climate change. 

Anthropogenic disturbances associated with the main agents identified in the cumulative activities scenario 

synergistically may interact with climate change and accelerate potential impacts to habitat; changes may 

be beneficial, adverse, or both. 

One beneficial aspect of climate change to peoples of the North Slope is the likelihood that fish/fishery 

resource diversity and biomass is expected to increase. However, some fish/fishery resource populations 

that seabirds, marine mammals, and subsistence users depend on are expected to contract, potentially 

triggering a variety of cascading impacts. 

III.H.1.m. Conclusion. Fish/fishery resources and EFH in the Chukchi and Beaufort seas potentially are 

affected by a variety of activities including seismic surveys on the OCS and in State waters; vessel and air 

traffic; oil and gas exploration, development, and production activities on the OCS and in State waters; 

subsistence activities; military activities; industrial and community development; and arctic warming. 

Seismic surveys, especially as mitigated under the Proposed Action alternatives, are not expected to add 

significantly to the impacts from past, present, and future activities. 

III.H.2. Marine Birds. 

III.H.2.a. Seismic-Survey Activities. Marine birds may be slightly affected by the Proposed Action and 

other seismic-survey activities in the Proposed Action area. The MMS requires that seismic-survey 

vessels not operate within 15 mi of each other at any one time. This limits signal interference and can 

provide movement corridors for fish, marine mammals, and marine birds. The total number and 

distribution of seismic-survey vessels operating in the area would result in a relatively small portion of the 

total Proposed Action area being ensonified at any one time. It is unlikely that fish prey species for marine 

birds would be affected by seismic activities to the degree that would adversely affect marine birds’ 

foraging success. If fish prey species leave the area of seismic-survey activity, that effect would be 

transitory and limited to small portions of the Proposed Action area. Because seismic-survey activities are 

temporary and geographically dispersed, the cumulative impacts to marine birds would not be significant. 

III.H.2.b. Vessel Traffic and Movements. Up to four seismic-survey vessels and their attendant support 

vessels would be added to the existing level of vessel traffic in the Chukchi and Beaufort seas. There may 

be localized, temporary displacement and disruption of feeding for some offshore species, but such impacts 

to marine birds would be similar to those caused by other larger vessels passing through the area. Any 

cumulative adverse impacts to marine birds would be negligible. 

III.H.2.c. Air Traffic. Aircraft needed to support seismic-survey vessels and possibly to conduct aerial 

monitoring for marine mammals would be a relatively small addition to existing commercial air traffic 

servicing local communities. No adverse cumulative impacts to marine birds are anticipated from air 

traffic required to support seismic-survey activities or related aerial monitoring. 

III.H.2.d. Conclusion. Marine birds in the Chukchi and Beaufort seas potentially are affected by seismic 

surveys on the OCS and in State waters and by vessel and air traffic. Seismic surveys, especially as 

mitigated under the Proposed Action alternatives, are not expected to add significantly to the impacts from 

past, present, and future activities. 

 PEA-198 
III.H.3. Threatened and Endangered Marine Mammals.

III.H.3.a. Bowhead Whales. There are no data available that indicate that, other than historic commercial 

whaling, any previous human activity has had a significant population-level adverse impact on the current 

status of BCB Seas bowheads or their recovery. The uncertainty of the stock structure adds some 

uncertainty to summaries of the status of bowhead populations that may be impacted by the Proposed 

Actions. However, currently available information indicates that at the population level, bowheads that use 

the Beaufort Sea and Chukchi Sea Planning Areas currently are resilient at least to the level of humancaused mortality and disturbance that currently exists within their range, and has existed since the cessation 

of commercial whaling. Data indicate that at least some bowheads are extremely long lived (100+ years or 

more). Thus, many of the individuals in this population already may have been exposed to a high number 

of disturbance events in their lifetimes. The primary known current, human-related cause of mortality is a 

regulated subsistence hunt by Alaskan Natives, which occurs at different times of the year in many of the 

coastal portions of their range. The existence of this hunt has focused Native, local, State, Federal, 

international, and industry research and monitoring attention on this stock and the development of 

mitigations intended to ensure its continued availability for subsistence take adequate to meet the needs of 

bowhead-hunting Native communities. Because the level of take is directly linked to the population 

abundance and status of this population, protection of the availability of whales for subsistence take is 

linked to protection needed to ensure the long-term viability of the population. Whether there are longlasting behavioral effects from this activity are unknown, but overall habitat use appears to be relatively 

unaffected. 

Available information does not indicate that the cumulative effects of all other past or currently occurring 

noise and disturbance-causing factors combined (e.g., oil and gas activities, shipping, subsistence hunting, 

and research activities), habitat alteration activities (e.g., gravel island construction, port construction), or 

local or distant pollution has had any long-lasting physiological, or other adverse effect(s) on the 

population. This population may be more responsive to human-created noise than many or most other 

cetacean populations. However, as the factors related to the variability in bowhead responsiveness to 

anthropogenic noise are unclear, and other populations are not as well studied, it also is unclear whether 

there is a human-related cause underlying the high level (at least in some instances) of behavioral 

responsiveness to human noise of the bowhead. There are not sufficient data about past human activities 

including, but not limited to, past offshore oil- and gas-related seismic surveys, or ice-management 

activities, to address whether there are any long-term impacts on their behavior from such activities in 

either evaluation area. 

The potential for cumulative effects to adversely affect bowhead whales is of great concern because of 

their current endangered status, which resulted from past human activity (overexploitation by 

commercial whalers); because of their importance as a subsistence species to Alaskan Native residents 

of coastal villages adjacent to their range; and because of their unusual ecology, which obligates their 

use of a relatively restrictive area during calving and spring migration. 

In addition to the detailed coverage in the Beaufort Sea multiple-sale EIS, the Biological Evaluation (BE) 

prepared for consultation with NMFS on Beaufort Sea Sale 195, and the recent BE prepared for NMFS on 

Arctic Region OCS activities (http://www.mms.gov/alaska/cproject/cproject.htm), several other documents 

have become available recently that are particularly useful as sources of information about potential 

cumulative effects on this population. These documents also provide information helpful in evaluating the 

potential significance of effects on the status and health of this population. These include: the IWC’s 

Scientific Committee’s in-depth assessment of BCB Seas stock of bowhead whales (IWC, 2004b); NMFS’ 

Biological Opinion on Issuance of Annual Quotas Authorizing the Harvest of Bowhead Whales to the 

Alaska Eskimo Whaling Commission for the Period 2003 through 2007 (NMFS, 2003a); NMFS’ Final 

Environmental Assessment for Issuing Subsistence Quotas to the Alaska Eskimo Whaling Commission for a 

Subsistence Hunt on Bowhead Whales for the Years 2003 through 2007 (NMFS, 2003b); papers evaluating 

whether this population should be delisted (Shelden et al., 2001, 2003; Taylor, 2003); and the NRC’s report 

Cumulative Environmental Effects of Oil and Gas Activities on Alaska’s North Slope (NRC, 2003a). The 

IWC reviewed and critically evaluated new information available on the bowhead whale at their 2005 

meeting (IWC, 2005a,b). This information and the associated discussions are summarized in the Report of 

 PEA-199 
the Subcommittee on Bowhead, Right and Gray Whales (IWC, 2005b). The 2003 Alaska Marine Mammal 

Stock Assessment for this stock remains the most recent finalized stock assessment available but an 

updated draft 2005 Stock Assessment is available for consideration (Angliss and Outlaw, 2005). 

III.H.3.a(1) Introductory Information Relevant to Evaluation and Interpretation of Potential 

Cumulative Effects on Bowheads. Bowhead whales are very large marine animals. They inhabit parts of 

the world where weather, day length, and remoteness make research on free-ranging animals difficult, 

extremely expensive, and sometimes dangerous. Many of the types of data that could reduce the level of 

uncertainty about potential impacts of some potential effectors, such as very large oil spills, cannot be 

acquired in any reasonable way. For example, many of the chronic impacts of oil pollution that have been 

documented in smaller mammals could not be detected in large cetaceans because of the limitations of 

studying them. They cannot be easily captured, weighed, examined, released, and then captured again. 

When they die, they typically die at sea, and evidence of the fact and cause of their death is lost. Bowheads 

cannot be brought into aquariums and subjected to oiling or noise experiments as some smaller marine 

mammals have been. Thus, for these and other reasons, there is uncertainty about the range of potential 

physiological, especially long-term sublethal, effects on these (and other large) whales from such factors as 

oil spills, high-energy noise, or contaminants. 

There also is some uncertainty about behavioral impacts of repeated exposure to noise and disturbance in 

the marine environment, whether that noise is from shipping, oil- and gas-related activities, or hunting. 

There is uncertainty about the potential effects of climate change because of uncertainty about what 

physical changes actually will occur, what the biological and human activity-related consequences of such 

changes will be, and how bowheads will respond to such changes. 

Because the potential effects of at least some specific factors are uncertain, an even greater level of 

uncertainty exists about the cumulative impact of all of the potential factors, especially over the long 

timeframes that must be considered for this species. 

While such uncertainty exists about the details of some but not all cumulative effects, it also is the case that 

the Western Arctic stock of bowheads is relatively very well studied and monitored. The overall current 

status of this population is not uncertain, despite the inherent uncertainty associated with some factors that 

might have had, or might be having, some adverse (or even positive) effects on it. Because some of the 

potential cumulative effects on this population are highly regulated (for example, subsistence hunting), we 

know clearly the level of at least some effects. These two points are important. We are able to view other 

potential effects against relatively detailed knowledge of population status and in light of rather detailed 

knowledge about the population level consequences of at least some known cumulative affecters (for 

example, subsistence hunting, past levels of offshore drilling activity). However, data on other potential 

effecters (e.g., past seismic surveys during the period of highest seismic survey activity and ice-breaking 

activities) are not sufficient to allow us to have such a view. 

III.H.3.a(2) Activities Considered. We have identified the following human actions, other than the 

Proposed Action, that either have had, are having, or are likely to have potential effects on BCB Seas 

bowhead whales: 

• historic commercial whaling; 

• past, present, and future subsistence hunting; 

• previous, present, and near-term future oil- and gas-related activity; 

• previous, present and near-term future non-oil and gas industrial development within the range of 

the bowhead; 

• past, current and near-term future research activities; 

• recent, current and future marine vessel-traffic and commercial-fishing; 

• pollution and contaminants baseline; and 

• arctic warming that has already occurred. 

 PEA-200 
As possible, we have tried to increase the transparency of the rationale underlying our conclusions about 

baseline and cumulative effects and to clarify the uncertainty, where it exists, in evaluation of the potential 

impact(s) of specific effectors. 

III.H.3.a(2)(a) Historical Commercial Whaling. Commercial hunting between 1848 and 1915 caused 

severe depletion of the bowhead population(s) that inhabits the Bering, Chukchi, and Beaufort seas. This 

hunting is no longer occurring and is not expected to occur again. Woody and Botkin (1993) estimated that 

the historic abundance of bowheads in this population was between 10,400 and 23,000 whales in 1848, 

before the advent of commercial whaling. Woody and Botkin (1993) estimated between 1,000 and 3,000 

animals remained in 1914, near the end of the commercial-whaling period. Data indicate that what is 

currently referred to as the Western Arctic stock (by NMFS) or as the Bering-Chukchi-Beaufort (BCB) 

Seas stock (by the IWC) of bowheads is increasing in abundance and has increased in abundance 

substantially since the last ESA consultation between MMS and NMFS involving the Chukchi Sea OCS 

Planning Area. As noted in the Section III.F.3, there are scientific analyses indicating that BCB Seas 

bowheads may have reached, or are approaching, the lower limit of their historic population size. There are 

related analyses supporting its removal from the list of threatened and endangered species. It is clear that 

commercial whaling between 1848 and 1915 was the human activity that had the greatest adverse effect on 

this population. Commercial whaling severely depleted bowhead whales. Commercial whaling also may 

have caused the extinction of some subpopulations and some temporary changes in distribution. 

III.H.3.a(2)(b) Past, Present, and Future Subsistence Hunting. Indigenous peoples of the Arctic and 

Subarctic of what is now Alaska have been hunting bowhead whales for at least 2,000 years (Stoker and 

Krupnik, 1993). Thus, subsistence hunting is not a new contributor to cumulative effects on this 

population. There is no indication that, prior to commercial whaling, subsistence whaling caused 

significant adverse effects at the population level. However, modern technology has changed the potential 

for any lethal hunting of this whale to cause population-level adverse effects if unregulated. Under the 

authority of the IWC, the subsistence take from this population has been regulated by a quota system since 

1977. Federal authority for cooperative management of the Eskimo subsistence hunt is shared with the 

Alaska Eskimo Whaling Commission (AEWC) through a cooperative agreement between the AEWC and 

the United States Department of Commerce, National Oceanic and Atmospheric Administration (NOAA) 

(see Appendix 9.5 of NMFS, 2003b). Additional discussion of the cumulative impacts of subsistence 

hunting on bowheads can be found in MMS’ Arctic Region Biological Evaluation (dated March 3, 2006) 

prepared for ESA Section 7 consultation (http://www.mms.gov/alaska/cproject/cproject.htm). 

The sustainable take of bowhead whales by indigenous hunters represents the largest known human-related 

cause of mortality in this population at the present time. Available information suggests that it is likely to 

remain so for the foreseeable future. While other potential effectors primarily have the potential to cause, 

or to be related to, behavioral or sublethal adverse effects to this population, or to cause the deaths of a 

small number of individuals, little or no evidence exists of other common human-related causes of 

mortality. Subsistence take, which all available evidence indicates is sustainable, monitored, managed, and 

regulated, helps to determine the resilience of the population to other effecters that could potentially cause 

lethal takes. The sustained growth of the BCB Seas bowhead population indicates that the level of 

subsistence take has been sustainable. Because the quota for the hunt is tied to the population size and 

population parameters (IWC, 2003a; NMFS, 2003b), it is unlikely this source of mortality will contribute to 

a significant adverse effect on the recovery and long-term viability of this population. 

Currently, Alaskan Native hunters from 10 villages harvest bowheads for subsistence and cultural purposes 

under a quota authorized by the IWC. Chukotkan Native whalers from Russia also are authorized to 

harvest bowhead whales under the same authorized quota. Bowheads are hunted at Gambell and Savoonga 

on St. Lawrence Island, and along the Chukotkan coast. On the northward spring migration, harvests may 

occur by the villages of Wales, Little Diomede, Kivalina, Point Hope, Wainwright, and Barrow. During 

their westward migration in autumn, whales are harvested by Kaktovik, Nuiqsut, and Barrow. At St. 

Lawrence Island, fall migrants can be hunted as late as December (IWC, 2004b). The status of the 

population is closely monitored, and these activities are closely regulated. 

There are adverse impacts of the hunting to bowhead whales in addition to the death of animals that are 

successfully hunted and the serious injury of animals that are struck but not immediately killed. Available 

 PEA-201 
evidence indicates that subsistence hunting causes disturbance to the other whales, changes in their 

behavior, and sometimes temporary effects on habitat use, including migration paths. Modern subsistence 

hunting represents a source of noise and disturbance to the whales during the following periods and in the 

following areas: during their northward spring migration in the Bering Sea, the Chukchi Sea in the spring 

lead system, and in the Beaufort Sea spring lead system near Barrow; their fall westward migration in 

subsistence hunting areas associated with hunting from Kaktovik, Cross Island, and Barrow; hunting along 

the Chukotka coast; hunting in wintering areas near St. Lawrence Island. Lowry, Sheffield, and George 

(2004) reported that indigenous hunters in the Beaufort Sea sometimes hunt in areas where whales are 

aggregated for feeding. When a subsistence hunt is successful, it results in the death of a bowhead. Data 

on strike and harvested levels indicate that whales are not always immediately killed when struck and some 

whales are struck but cannot be harvested. Whales in the vicinity of the struck whale could be disturbed by 

the sound of the explosive used in the hunt, the boat motors, and any sounds made by the injured whale. 

The NMFS (2003a) pointed out that whales that are not struck or killed may be disturbed by noise 

associated with the approaching hunters, their vessels, and the sound of bombs detonating: “...the sound of 

one or more bombs detonations during a strike is audible for some distance. Acousticians, listening to 

bowhead whale calls as part of the census, report that calling rates drop after such a strike ...” (NMFS, 

2003a:35). We are not aware of data indicating how far hunting-related sounds (for example, the sounds of 

vessels and/or bombs) can propagate in areas where hunting typically occurs, but this is likely to vary with 

environmental conditions. It is not known if whales issue an “alarm call” or a “distress call” after they, or 

another whale, are struck prior to reducing call rates. 

The NMFS (2003a) reported that: 

...whales may act skittish” and wary after a bomb detonates, or may be displaced further offshore 

(E. Brower, pers. com.). However, disturbances to migration as a result of a strike are temporary 

(J. George, 1996), as evidenced when several whales may be landed at Barrow in a single day. 

There is some potential that migrating whales, particularly calves, could be forced into thicker 

offshore ice as they avoid these noise sources. The experience of Native hunters suggests that the 

whales would be more likely to temporarily halt their migrations, turn 180 degrees away...(i.e., 

move back through the lead systems), or become highly sensitized as they continue moving (E. 

Brower, pers. com.). 

Because evidence indicates that bowhead whales are long-lived, some bowhead whales may have been 

in the vicinity where hunting was occurring on multiple, perhaps dozens or more, occasions. Thus, 

some whales may have cumulative exposure to hunting activities. This form of noise and disturbance 

adds to noise and disturbance from other sources, such as shipping and oil and gas-related activities. 

To the extent such activities occur in the same habitats during the period of whale migration, even if 

the activities (e.g., hunting and shipping) themselves do not occur simultaneously, cumulative effects 

from all noise and disturbance could affect whale habitat use. However, we are not aware of 

information indicating long-term habitat avoidance has occurred with present levels of activity. 

Additionally, if, as reported above, whales become more “skittish” and more highly sensitized 

following a hunt, it may be that their subsequent reactions, over the short-term, to other forms of noise 

and disturbance are heightened by such activity. Data are not available that permit evaluation of this 

possible, speculative interaction. 

Noise and disturbance from subsistence hunting serves as a seasonally and geographically predictable 

source of noise and disturbance to which other noise and disturbance sources, such as shipping and oil and 

gas-related activities, add. To the extent such activities occur in the same habitats during the period of 

whale migration, even if the activities (for example, hunting and shipping) themselves do not occur 

simultaneously, cumulative effects from all noise and disturbance could affect whale habitat use. 

Subsistence hunting attaches a strong adverse association to human noise for any whale that has been in the 

vicinity when other whales were struck. 

In summary, it is not unlikely that up to 82 (67 + 15) whales may be struck (with the presumption that they 

could die, even if not retrieved) in a given year from 2004 through 2007, as long as a total of 280 is not 

exceeded over the 5-year period. If the population of whales continues to increase in abundance, it is not 

unlikely that this quota could be increased for the next 5-year period (2008-2012). However, it also is 

 PEA-202 
likely that the quota will continue to be a small percentage of the estimated population size and will not 

have significant adverse impacts on the population. The subsistence take, while additive, actually is small 

as compared to the capacity of the population to absorb it and to thrive. We are aware of no other known 

potential human-related effects that approach, or could reasonable be predicted to approach, the level of 

this known removal. This activity also results in noise and disturbance that may have temporary effects on 

habitat use. We are not aware of information suggesting there have been any long-term modifications of 

habitat use due to this form of noise and disturbance. However, we also emphasize that the hunt is highly 

regulated, has limits on take, and places direct prohibition on the take of females with calves. Other 

potential effecters have less controllable effects, unless also purposely mitigated and shaped. 

The existence of this hunt results in a relatively high level of Native, local, State, national, and international 

study, monitoring, and management of this population(s) which provides some safeguards for its long-term 

viability. Mitigations that are focused on protecting the hunt may have the unintended effect of increasing 

overall impacts on the whales by focusing other (e.g., industrial) activities into periods and places that may 

act as temporary hunting refuges for the whales unless MMS and NMFS also deliberately design 

mitigations to offset such an impact. 

III.H.3.a(2)(c) Climate Change. Climate change also is referred to as arctic warming, global warming, or 

climate warming. We note that environmental effects compatible with climate warming already have 

occurred in the Arctic. There is a growing consensus that more such changes are likely to occur. 

Additional discussion of the cumulative impacts of climate change on bowheads can be found in MMS’ 

Arctic Region Biological Evaluation (dated March 3, 2006) prepared for ESA Section 7 consultation 

(http://www.mms.gov/alaska/cproject/cproject.htm). 

Climate warming could potentially affect bowheads in ways including: 

• increased noise and disturbance related to increased shipping, and possibly related to increased 

development, within their range; 

• increased interactions with commercial fisheries, including increased noise and disturbance, 

incidental take, and gear entanglement; 

• decreases in ice cover with the potential for resultant changes in prey species concentrations and 

distribution; related changes in bowhead whale distributions; changes in subsistence-hunting 

practices that could result in smaller, younger whales being taken and, possibly, in fewer whales 

being taken; 

• more frequent climatic anomalies, such as El Niños and La Niñas, with potential resultant changes 

in prey concentrations; and 

• a northern expansion of other whale species, with the possibility of increased overlap in the 

northern Bering and/or the Chukchi seas. 

The IUCN /Species Survival Commission (IUCN/SSC) (IUCN, 2003) concluded that a workshop by the 

IWC in 1996: 

...placed the issue of climate change, including ozone depletion, firmly on the cetacean 

conservation agenda.... Effects of climate change are complex and interactive, making them 

analytically almost intractable. This workshop report acknowledges the difficulties in establishing 

direct links between climate change and the health of individual cetaceans, or indirect links 

between climate change and the availability of cetacean prey.... 

We emphasize that there is uncertainty associated with many of the predictions about potential climate 

changes, especially at a regional level, and associated environmental changes that could occur. However, if 

this change occurs, it is likely that shipping would increase throughout the range of the bowhead, especially 

in the southern portions of the Beaufort Sea. If commercial fisheries were to expand into the Beaufort Sea, 

as discussed as a possible outcome of climate warming, bowhead whale death and or injury due to 

interactions with fishing gear, possibly injury and/or death due to incidental take in commercial fisheries, 

and temporary effects on behavior potentially could occur. There are, however, no data that would permit 

us to quantitatively predict such types of effects. 

 PEA-203 
With respect to observations and conclusions specifically pertinent to bowhead whales, the SEARCH SSC 

(2001:2) noted that: 

Available data point to long-term and recently augmented reductions in sea-ice cover (Maslanki et 

al., 1996; Bjorgo et al., 1997; Cavalieri et al., 1997; Zakharov, 1997; Rothrock et al., 1999).... 

Perhaps most alarming, there have...been significant reductions in sea ice extent (Parkinson et al., 

1999) and a 43% reduction in average sea ice thickness (Rothrock et al., 1999) in recent decades. 

Perhaps the greatest potential adverse effect associated with global warming could occur if predictions that 

the Northwest Passage may become ice free for significant lengths of time prove accurate, opening sea 

routes across the Beaufort Sea and increasing shipping in all parts of the range of the Western Arctic stock 

of the bowhead whale. SEARCH SSC (2001:30) concludes that: 

...greater access and longer navigation seasons may be possible in Hudson Bay, the Chukchi and 

Beaufort seas, and along the Russian Arctic coast if present sea ice trends continue. The 

significant reduction in the thickness of arctic sea ice...and...winter multiyear ice...suggest the 

possibility of shipping in the central Arctic Ocean sometime during the 21st century. It is 

significant to note that at the end of the 20th century nuclear and non-nuclear icebreakers (from 

Canada, Germany, Russia, Sweden, and the U.S.) have made summer transits to the North Pole 

and operated throughout the central Arctic Ocean.... Thus it is conceivable that surface ships in 

the future will not have to confine their operations solely to the arctic marginal seas. 

We conclude that the potential effects of global warming on this population of bowhead whales are 

uncertain. There is no current evidence of negative effects on the whales. There is no evidence suggesting 

that many of the changes that could occur, such as changes in timing of migrations and shifts in 

distribution, would be associated with overall adverse effects on these whales. In Shelden et al.’s (2003) 

response to Taylor’s statements regarding the expectation of future downward trends in abundance based 

on what he termed “available evidence” regarding global warming, they point out that Taylor did not 

provide citations supporting this claim. Shelden et al. (2003:918-919) state that: 

Although available data do indicate that the Bering Sea environment is changing (e.g., Angel & 

Smith 2002), we are aware of no evidence that environmental changes will be detrimental to the 

population in the foreseeable future. In fact, our review...on this issue suggests that climate 

change may actually result in more favorable conditions for BCB bowheads. 

We have, however, identified some potential changes that could result in adverse impacts on bowhead 

whales, were they to occur. In our 2004 Biological Evaluation for Sale 195 (USDOI, MMS, 2004), we 

greatly expanded and summarized information on the potential effects of climate change on bowhead 

whales. In 2005, a symposium High Latitude Sea Ice Environments: Effects on Cetacean Abundance, 

Distribution and Ecology was held as a premeeting to the IWC Annual meeting in 2005 (IWC, 2005a). At 

this symposium, concerns we identified in the 195 Biological Evaluation (USDOI, MMS, 2004) were again 

identified: increased exposure to killer whale predation; competition with other species; ship traffic; noise; 

pollution; and fisheries interactions. In addition, they noted that a reduction in sea ice may affect the 

logistics of the harvest and raised concerns about thermoregulatory issues. The IWC Scientific Committee 

(IWC, 2005a:23) summarized that: “...the Committee...found it difficult to predict how bowhead whales 

might be affected by large-scale oceanographic changes in the future.” 

Angliss and Lodge (2002:174) stated that: 

Ice-associated animals, such as the bowhead whale, may be sensitive to changes in Arctic weather, 

sea-surface temperatures, or ice extent, and the concomitant change on prey availability. There 

are insufficient data to make reliable predictions of the effects of Arctic climate change on 

bowhead whales. 

 PEA-204 
Based on our previous and continued review of available information, we agree with these general 

conclusions. However, we believe that evidence is accumulating that increased noise and disturbance in 

bowhead summer, autumn, and potentially spring habitat due to increased shipping and industrial activity 

that occurs as a result of climate warming has begun to occur and is likely to continue. 

III.H.3.a(2)(d) Commercial Fishing, Marine Vessel Traffic, and Research Activities. Based on available 

data, previous incidental take of bowhead whales apparently has occurred only rarely. Additional 

discussion of the cumulative impacts of commercial fishing, vessel traffic, and research activities on 

bowheads can be found in MMS’ Arctic Region Biological Evaluation (dated March 3, 2006) prepared for 

ESA Section 7 consultation (http://www.mms.gov/alaska/cproject/cproject.htm). 

The bowhead’s association with sea ice limits the amount of fisheries activity occurring in bowhead 

habitat. However, as noted in the section on climate change, the frequency of such interactions in the 

future would be expected to increase if commercial-fishing activities expand northward, with resultant 

increases in temporal and, especially, spatial overlap between commercial-fishing operations and bowhead 

habitat use. There is some uncertainty about whether such expansion will occur. Increases in spatial 

overlap alone could result in increased interactions between bowheads and derelict fishing gear. 

Potential effects on bowhead whales from commercial-fishing activities include incidental take in the 

fisheries and/or entanglement in derelict fishing gear resulting in death, injury, or effects on the behavior of 

individual whales; disturbance resulting in temporary avoidance of areas; and whales being struck and 

injured or killed by vessels. Bowheads have been entangled in ropes from crab pots, harpoon lines, or 

fishing nets; however, the frequency of occurrence is not known. 

Marine vessel traffic, in general, can pose a threat to bowheads because of the risk of ship strikes. 

Additionally, noise associated with ships or other boats potentially could cause bowheads to alter their 

movement patterns or make other changes in habitat use. Pollution from marine vessel traffic, especially 

from large vessels such as large cruise ships, also could cause degradation of the marine environment and 

increase the risk of the whales’ exposure to contaminants and disease vectors. 

Available evidence indicates that bowheads either do not often encounter vessels or they avoid interactions 

with vessels, or that interactions usually result in the animals’ death. We believe this general conclusion 

about ship strikes is likely to be valid. We also agree with the conclusion by NMFS (2003b) that the rate 

may have increased slightly in recent years. 

Clapham and Brownell (1999) summarized that “...effects of ship noise on whale behavior and ultimately 

on reproductive success are largely unknown.” The NMFS (2003b) concluded that the greatest potential 

impact to bowhead whales from research in the arctic was from underwater noise generated by icebreakers. 

They cite the Western Arctic Shelf Basin Interactions (SBI) project, which operated from the U.S. Coast 

Guard Healy and Polar Star icebreakers. This was a multiyear, interdisciplinary program aimed at 

investigating the impacts of climate change on biological, physical, and geochemical processes in the 

Chukchi and Beaufort Shelf Basin in the Western Arctic Ocean. 

Richardson et al. (1995a:Table 6.5) reported estimated source levels for similarly sized icebreakers to range 

from 177-191 db re 1 μPa-m. During icebreaking, extremely variable increases in broad-band (10-10,000 

Hz) noise levels of 5-10 dB are caused by propeller cavitation. Based on previous studies of bowhead 

response to noise, such sound could result in temporary avoidance of animals from the areas where the 

icebreakers were operating and potentially cause temporary deflection of the migration corridor, depending 

of the location of the icebreakers. SEARCH SSC (2001) (citing Brigham, 1998, 2000) point out that from 

1977-1998, there have been 27 icebreaker trips to the North Pole (presumably not all in the range of this 

stock of bowhead) for science and tourism. 

Richardson et al. (1995a:301) concluded that: “Ships and larger boats routinely use fathometers, and 

powerful side-looking sonars are common on many military, fishing, and bottom-survey vessels.... Sounds 

from these sources must often be audible to marine mammals and apparently cause disturbances in some 

situations.” 

 PEA-205 
There has been speculation recently that commercial shipping through the Northwest Passage is likely to 

substantially increase in the coming decades. Many shipping experts believe that “in-and-out” shipping 

(e.g., shipping from the Pacific Ocean or Bering Sea through the Chukchi Seas into the Beaufort and then 

back again) is likely to increase well in advance of regular shipping through the Northwest Passage. 

The Western Arctic bowhead has been the focus of research activities that could, in some instances, cause 

minor temporary disturbance of the whales. During research on the whales themselves, the reactions of the 

whales generally are closely monitored to minimize potential adverse effects. Additionally, research 

conducted primarily for reasons other than the study of the bowhead has also occurred within the range of 

the bowhead. In some cases, such research has the potential to adversely affect the whales through the 

introduction of additional noise, disturbance, and low levels of pollution into their environment. 

The NMFS recently initiated photo-identification studies. The MMS will be procuring a large study aimed 

at better understanding the importance of feeding areas in the western Alaskan Beaufort Sea. In these 

future activities, as in the past, the primary result of ship-based activities could be temporary disturbance of 

individual whales from a highly localized area. Whales might slightly and temporarily alter their habitat 

use to avoid large vessels. Whales also could be temporarily harassed or disturbed by low-flying airplanes 

during photo-identification work. All such effects are expected to be of short duration. Aerial surveys 

generally are flown at a height such that they do not cause harassment. 

Research vessels also sometimes introduce noise intentionally, not just incidentally, into the 

environment as part of the ship’s operating systems or to enable the collection of specific types of data 

(e.g., seismic survey data). 

Submarines are highly valued platforms for a variety of oceanic research in part because they are relatively 

quiet, enabling the use of active and passive acoustic technologies for a variety of studies. Information 

about the response of bowheads to resting or transiting submarines is not available to MMS. U.S. Navy 

submarines are likely to continue to be used as platforms in the future. 

In 2003, there was concern by Alaskan Native whalers that barge traffic associated with oil and gas 

activities might have caused bowhead whales to move farther offshore and, thus, to be less accessible to 

subsistence hunters.. 

In addition to acting as a source of noise and disturbance, marine vessels could potentially strike bowhead 

whales, causing injury or death. 

We conclude that some past and present research-related noise and disturbance could potentially have 

caused, and can cause, harassment and, possibly, temporary displacement of individual whales. Such noise 

and disturbance add to cumulative levels of noise in the whales’ environment. At present, available 

information does not indicate that such noise is having behavioral or physiological adverse effects on the 

bowheads in this stock. However, available information is not sufficient to form any conclusions about 

such potential effects. We are not aware of any information that suggests long-term displacement from 

important habitats has occurred, that indicates the population is suffering any significant population-level 

effect from any single affecter, or that indicates that the cumulative effects, including those from research 

activities, would have such an effect. 

III.H.3.a(2)(e) Pollution and Contaminants. Initial studies of bowhead tissues collected from whales 

landed at Barrow in 1992 (Becker et al., 1995) indicate that bowhead whales have very low levels of 

mercury, PCB’s, and chlorinated hydrocarbons, but they have fairly high concentrations of cadmium in 

their liver and kidneys. The study concluded that the high concentration of cadmium in the liver and 

kidney tissues of bowheads warrants further investigation. Becker (2000) noted that concentration levels of 

chlorinated hydrocarbons in bowhead whale blubber generally are an order of magnitude less than what has 

been reported for beluga whales in the arctic. This probably reflects the difference in the trophic levels of 

these two species; the bowhead being a baleen whale feeding on copepods and euphausiids, while the 

 PEA-206 
beluga whale being toothed whale feeding at a level higher in the food web. The concentration of total 

mercury in the liver also is much higher in beluga whales than in bowhead whales. 

Bratton et al. (1993) measured organic arsenic in the liver tissue of one bowhead whale and found that 

about 98% of the total arsenic was arsenobetaine. Bratton et al. (1997) looked at eight metals (arsenic, 

cadmium, copper, iron, mercury, lead, selenium, and zinc) in the kidneys, liver, muscle, blubber, and 

visceral fat from bowheads harvested from 1983-1990. They observed considerable variation in tissue 

metal concentration among the whales tested. Metal concentrations evaluated did not appear to increase 

over time between 1983 and 1990. Based on metal levels reported in the literature for other baleen whales, 

the metal levels observed in all tissues of the bowhead are similar to levels in other baleen whales. The 

bowhead whale has little metal contamination as compared to other arctic marine mammals, except for 

cadmium, which requires further investigation as to its role in human and bowhead whale health. The 

study recommended limiting the consumption of kidney from large bowhead whales pending further 

evaluation. 

Cooper et al. (2000) analyzed anthropogenic radioisotopes in the epidermis, blubber, muscle, kidney, and 

liver of marine mammals harvested for subsistence food in northern Alaska and in the Resolute, Canada 

region. The majority of samples analyzed had detectable levels of 137Cs. Among tissues of all species of 

marine mammals analyzed, 137Cs was almost always undetectable in the blubber and significantly higher in 

epidermis and muscle tissue than in the liver and kidney tissue. The levels of anthropogenic radioisotopes 

measured were orders of magnitude below levels that would merit public health concern. The study noted 

there were no obvious geographical differences in 137Cs levels between marine mammals harvested in 

Resolute, Canada and those from Alaska. However, the 137Cs levels in marine mammals were two to three 

orders of magnitude lower than the levels reported in caribou in northern Canada and Alaska. 

Based on the use of autometallography (AMG) to localize inorganic mercury in kidney and liver tissues for 

five bowhead whales, Woshner et al. (2002:209) reported that “AMG granules were not evident in 

bowhead tissues, confirming nominal mercury (Hg) concentrations.” Detected concentrations ranged from 

0.011-0.038 micrograms per gram (μg/g) wet weight for total mercury. Mössner and Ballschmiter (1997) 

reported that total levels of 310 nanograms per gram (ng/g) polychlorinated biphenyls and chlorinated 

pesticides in bowhead blubber from the North Pacific/Arctic Ocean, an overall level many times lower than 

that of other species from the North Pacific or Arctic Ocean (beluga whales [2,226 ng/g]; northern fur seals 

[4,730 ng/g]) and than that of species from the North Atlantic (pilot whale [6,997 ng/g]; common dolphin 

[39,131 ng/g]; and harbor seal [70,380 ng/g]). However, while total levels were low, the combined level of 

3 isomers of the hexachlorocyclohexanes was higher in the bowhead blubber (160 ng/g) tested than in 

either the pilot whale (47 ng/g), the common dolphin (130 ng/g), and the harbor seal (140 ng/g). These 

results confirmed results expected due to the lower trophic level of the bowhead relative to the other marine 

mammals tested. 

In the Beaufort Sea multiple-sale EIS in 2003, we concluded that the levels of metals and other 

contaminants measured in bowhead whales appear to be relatively low, with the exception of cadmium. 

Since the finalization of the multiple-sale EIS, additional information (included in the review presented 

above) on contaminants in BCB bowheads has become available. This information supports this same 

general conclusion. 

III.H.3.a(2)(f) Offshore Oil- and Gas-Related Activities and other Industrial Activities. We provide a 

description of past, current, and reasonably foreseeable oil and gas activities in Section III.C. Additional 

discussion of the cumulative impacts of offshore oil and gas activities and other industrial activities on 

bowheads can be found in MMS’ Arctic Region Biological Evaluation (dated March 3, 2006) prepared for 

ESA Section 7 consultation (http://www.mms.gov/alaska/cproject/cproject.htm). 

Offshore petroleum exploration, development, and production activities have been conducted in Alaska 

State waters or on the Alaska OCS in the Beaufort and Chukchi seas since 1979. MMS-permitted seismic 

surveys have been conducted in the Chukchi and Beaufort seas since the late 1960’s and early 1970’s. 

Much more seismic activity has occurred in the Beaufort Sea OCS than in the Chukchi Sea OCS. 

 PEA-207 
Compared to the North Slope/Beaufort Sea, there has been little oil- and gas-related activity in the Chukchi 

Sea. 

Many offshore activities required ice management (icebreaking), helicopter traffic, fixed wing monitoring, 

other support vessels, and, in some cases stand-by barges. 

Available information does not indicate that oil- and gas-related activity (or any recent activity) has had 

detectable long-term adverse population-level effects on the overall health, current status, or recovery of 

the BCB Seas bowhead population. Data indicate that the BCB Seas bowhead whale population has 

continued to increase over the timeframe that oil and gas activities has occurred. There is no evidence of 

long-term displacement from habitat. However, there are no long-term oil and gas developments in the 

offshore within bowhead high use areas. Past behavioral (primarily, but not exclusively, avoidance) effects 

on bowhead whales from oil and gas activity have been documented in many studies. Inupiat whalers have 

stated that noise from seismic surveys and some other activities at least temporarily displaces whales 

farther offshore, especially if the operations are conducted in the main migration corridor. As noted in the 

section on effects, recent monitoring studies indicated that most fall migrating whales avoid an area with a 

radius about 20-30 km around a seismic vessel operating in nearshore waters. We are not aware of data 

that indicate that such avoidance is long-lasting after cessation of the activity. 

Available data, however, are inadequate to fully address issues about effects of past oil and gas activity in 

the Beaufort Sea on bowhead behavior. The MMS study 2002-071 titled GIS Geospatial Data Base of OilIndustry and Other Human Activity (1979-1999) in the Alaskan Beaufort Sea provided a compilation of 

available data on the location, timing, and nature of oil- and gas-related activities from 1979-1999. It was 

intended to provide a “...database to address concerns expressed by subsistence hunters and others living 

within ...villages of the Beaufort Sea about the possible effects that oil and gas activity, particularly 

seismic activity, drilling, and oil and gas support vessel activities may have on the behavior of...especially 

the bowhead whale.” However, “(S)uch an analysis requires an adequate level of detail...,” “...there are 

significant gaps in the data for the period 1979-1989” (Wainwright, 2002:viii) and “(V)ery limited 

information was obtained on ice management” (Wainwright, 2002:52). For all but 2 years, 1985-1986, 

during the period 1979-1989, inclusive, Wainwright (2002:Table 2, p. 8) assessed the availability of 

information about 2D/3D seismic surveys conducted under OCS permit as a 0 out of a possible 3. This 

score of 0 indicates: “Significant data sets are missing. These data are not suited for statistical analysis.” 

During this same period, they also provide a rank of 0 out of 3 to categorize the completeness and adequacy 

of information on seismic surveys under State MLUP permit. For the entire period of study (1979-1998), 

they rate the completeness and adequacy of information on seismic and acoustic surveys in State waters 

without permits, ice management, and other vessel activity all as 0 (see Wainwright, 2002:Table 2, p. 8). 

Thus, while data on the bowhead status are adequate to determine that the BCB Seas bowhead whale 

population apparently continued to recover during the periods when past and current levels of oil and gas 

activities were occurring, we cannot adequately assess potential effects on patterns or durations of bowhead 

habitat use. Wainwright (2002:13) summarized that “...it was not possible to compile adequate data on 

seismic activity prior to 1990.” Because of the inadequacy of the data on activities, and because of the 

limitations inherent in studying large baleen whales, we also cannot assess whether there were any adverse 

health effects to individuals during the period of relatively intensive seismic survey activity in the 1980’s. 

Data for the 1990’s are better, and the levels of activity are more comparable to those anticipated in the 

near future. There were no geohazard (high-resolution seismic surveys) surveys during the fall migration 

period in the 1990’s (Wainwright, 2002). Table 4 of Wainwright (2002:45) gives information about the 

kinds and levels of seismic and acoustic activity in the 1990’s. Figure 11 of Wainwright (2002:41) 

summarizes that except in 1990 and 1998, seismic surveying activity was completed by September 30, and 

most of the activity was between September 1-15. During 3 of the years, there was no seismic surveying 

activity during the fall migration period. Figures 2a through 10c of Wainwright (2002) depict all known 

seismic, acoustic, and drilling activity during the period of September 1-October 20 from 1990-1998. 

Data on past drilling in both Federal and State waters is relatively complete, especially since 1990, and are 

summarized in Tables V-11 and B1 here and in Wainwright (2002). Data on other activities, such as 

hunting activity, barge traffic, and shipping noise are incomplete. Thus, while it is clear there have been 

 PEA-208 
multiple noise and disturbance sources in the Beaufort Sea over the past 30 years, because of the 

incompleteness of data, even for the 1990’s, for many types of activities, we cannot evaluate the totality of 

past effects on bowhead whales resulting from multiple noise and disturbance sources (e.g., 2D seismic in 

State and Federal waters, drilling, ice management, high-resolution acoustic surveys, vessel traffic, 

construction, geotechnical bore-hole drilling, aircraft surveys, and hunting). Because data also are 

incomplete for the Chukchi Sea, we reach the same general conclusions. 

Potential Impacts of Noise from Production Facilities. It has been documented that bowhead and other 

whales avoid various industrial activities if the received sound levels associated with the activity are 

sufficiently strong (see summaries and references in Richardson et al., 1995a, and NRC, 2003). The 

monitoring of sound associated with the construction and production activities at the BPXA Northstar 

facility and the monitoring of marine mammals in nearby areas has recently provided additional 

information relative to assessing potential impacts of oil and gas production-related noise on bowhead 

whales. Northstar is built on an artificial gravel island in State of Alaska waters about 54 mi (87 km) 

northeast of Nuiqsut. To date, it is the only offshore oil production facility north of the barrier islands in 

the Beaufort Sea. 

North Slope residents have expressed concern that the bowhead whale autumn migration corridor might be 

deflected offshore in the Northstar area due to whales responding to underwater sounds from construction, 

operation, and vessel and aircraft traffic associated with Northstar. Richardson and Thompson (2004) and 

other researchers working with LGL and Greeneridge Sciences, Inc. undertook studies during the openwater period to determine both the underwater noise levels at various distances north of Northstar and 

potential impacts on bowhead whales north of the island, as assessed by locations determined by 

vocalization locations. The final report confirms the basic findings previously referred to. Additional 

details from the final report are provided below. 

Blackwell and Greene (2004:4-22) summarized that, in the absence of boats, “During both 

construction....and the drilling and production phase..., island sounds...reached background values at 

distances of 2-4 km...” in quiet ambient conditions. Blackwell and Greene (2004) concluded that during 

the open water season, vessels such as self-propelled barges, crew boats, and tugs were the tugs, selfpropelled barges) were the primary contributors to the underwater sound field. Broadband sounds from 

vessels near Northstar were often detected offshore as far as approximately 30 km. “Background levels 

were not reached in any of the open-water recordings with boats present at Northstar” (Blackwell and 

Greene, 2004:4-25). At Northstar in 2001, two 61.5 ft. (18.7 m) crew vessels operated between West Dock 

and Northstar between 23 July 2001 and 7 October 2001 for a total of 824 round trips (Williams and 

Rodrigues, 2003). Tone above 10 kHz characterized production sound. In air sounds typically reached 

background levels at 1-4 km, but an 81-Hz tone was detectable 37 km from the island (Blackwell and 

Greene, 2004). 

During the normal “open water period” in 2001 (16 June to 31 October), there were approximately 989 

roundtrip helicopter flights to Northstar. 

Richardson et al. (2004:8-2) summarized that data in 2001 provided evidence of a slight displacement 

of the “...southern edge of the bowhead whale migration corridor at times with high levels of industrial 

sound, but no such effect was evident in 2003, and the 2002 results were inconclusive.” 

It is important to note that this study did not have a “Northstar-absent” control, a point noted by the authors 

of the report (see Greene et al., 2003:7-5). That is, there are no locations of whales based on vocalizations 

absent any sound from Northstar to be compared with localizations given Northstar sound. Limitations of 

the study are well discussed by the authors in the report. However, the available data on bowhead 

locations, coupled with data on noise propagation, indicate that if noise from Northstar is having an impact 

on whale movements, the effect, if it exists, is not dramatic. 

On-Ice 2D/3D Seismic Surveys. The 2D/3D seismic surveying in shallow water could also be conducted 

during the winter over the ice and we anticipate that some on-ice surveys could occur. Seismic profiling on 

shore-fast ice using vibroseis is another source of introduction of noise into the arctic environment. 

 PEA-209 
Richardson et al. (1995a) summarized that typical signals associated with this kind of seismic activity 

sweep from 10-70 Hz but harmonics extend to about 1.5 kHz (Richardson et al., 1995a). In this activity, 

hydraulically driven pads mounted beneath a line of trucks are used to vibrate, and thereby energize the ice. 

Noise incidental to the activity is introduced by the vehicles associated with this activity. 

These on-ice surveys often extend into the period in April when bowhead whales begin to be observed at 

Barrow and are present in the Chukchi and Beaufort Sea in the spring lead system. However, during that 

period in the Beaufort Sea, the whales are far offshore in the spring leads and distant from shallow water 

areas where such surveys could occur. On-ice surveys are not expected in the Chukchi Sea. These surveys 

have occurred regularly in nearshore areas of the Alaska Beaufort Sea over the past 30 years. If bowhead 

whales detect these sounds, there is no indication of any adverse effect on their migration or population 

recovery. For these reasons, we believe that on-ice surveys are not likely to have detectable adverse effects 

on bowhead whales. As these surveys are not expected to occur in the Chukchi Sea, we believe that fin and 

humpback whales will not be exposed to these sounds even from a distance. 

Future Activities. Potential cumulative effects to bowhead whales from near-term future oil and gas 

activities could include behavioral responses to seismic surveys; aircraft and vessel traffic; exploratory 

drilling, and production that take place at varying distances from the whales. It also could include effects 

from small and large oil spills (if a large oil spill were to occur). In general, bowheads may try to avoid 

vessels or seismic surveys if closely approached, but they do not respond very much to aircraft flying 

overhead at 1,000 ft or more. Bowheads try to avoid close approaches by motorized vessels. The response 

of individual bowheads to sound, such as drillship sounds, is variable (for example, Richardson, Wells, and 

Würsig, 1985; Richardson and Malme, 1993). However, some bowheads are likely to change their 

migration speed and swimming direction to avoid getting close to them. Whales appear less concerned 

with stationary sources of relatively constant noise than with moving sources. Bowheads do not seem to 

travel more than a few kilometers in response to a single disturbance, and behavioral changes are 

temporary, lasting from minutes (for vessels and aircraft) up to 12-24 hours for avoidance (for seismic 

activity). In some other species, responsiveness is linked to both context and to the sex and/or reproductive 

status of the animal. For example, in studies in Australia, humpback whale females with calves show 

greater avoidance of operating seismic boats than do males. Detailed discussions of how these various 

activities may affect bowheads can be found in the effects section above. 

Overall, bowhead whales exposed to noise-producing activities associated with offshore oil and gas 

exploration and production activities would be most likely to experience temporary, nonlethal behavioral 

effects such as avoidance behavior. Effects could potentially be longer term, if sufficient oil and gas 

activity were to occur in a localized area. 

The IWCSC (IWC, 2005a:45) received an update on, and discussed, noise pollution (including seismic 

surveys), the limitations of mitigation measures, and the use of alternative technology at their 2004 annual 

meeting. The scientific committee stated that: “Detail on the type, number and configuration of airguns is 

needed to evaluate source capabilities and the potential impact on cetaceans.” 

There is no indication that human activities (other than historic commercial whaling) have caused longterm displacement in bowheads. Available information indicates that there is some potential for a level of 

noise and/or related disturbance to be reached that would potentially have such an effect in local areas. 

Existing regulatory authority under both the MMPA and the ESA is sufficient to keep such a situation from 

occurring and to mitigate many of the potential impacts from noise and other disturbance. 

Native hunters believe that there is potential for increased noise (for example, from shipping and/or oil and 

gas development) to drive whales farther from shore, decreasing their availability to subsistence hunters, 

and potentially reducing mortality from this source. If such an effect occurred, it could produce a 

countervailing effect to adverse effects on the whale population. As noted in the section on subsistence 

hunting, cumulative noise and disturbance associated with oil and gas activities, shipping, and subsistence 

hunting could potentially have an additive or even synergistic effect on bowhead whale habitat use. 

However, at present, we are aware of no other information that suggests such an effect would be likely to 

occur or that such effects have occurred. 

 PEA-210 
Effects of a large oil spill in Federal or State waters would most likely result in nonlethal temporary or 

permanent effects. However, we reiterate that due to the limitations of available information and due to the 

limitations inherent in the study of baleen whales, there is uncertainty about the range of potential effects of 

a very large spill on bowhead whales, especially if a large aggregation of females with calves were to be 

contacted by a large or very large spill of fresh oil. The NMFS has concluded that, given the abundance of 

plankton resources in the Beaufort Sea (Bratton et al., 1993), it is unlikely that the availability of food 

resources for bowheads would be affected. As summarized in the effects section, individuals exposed to 

spilled oil may inhale hydrocarbon vapors, experience some damage to skin or sensory organs, ingest 

spilled oil or oil-contaminated prey, feed less efficiently because of baleen fouling, and lose some prey 

killed by the spill. Prolonged exposure to freshly spilled oil, or possibly exposure to high concentrations of 

freshly spilled oil, could kill or injure whales. Because of existing information available for other 

mammals regarding the toxic effects of fresh crude oil, and because of inconclusive results of studies on 

cetaceans after the Exxon Valdez oil spill, we are uncertain about the potential for mortality of more than a 

few individuals. Such potential probably is greatest if a large aggregation of feeding or milling whales, 

especially an aggregation containing relatively high numbers of calves, was contacted by a very large slick 

of fresh oil. Such aggregations occasionally have been observed in open-water conditions north of Smith 

Bay and Dease Inlet, near Cape Halkett and other areas. 

Available information suggests that the potential for oil-industry activities outside of the Beaufort Sea and 

Chukchi Sea to contribute to cumulative effects on this stock of bowhead whales is still limited. This 

remains the case. Industry has not expressed interest in the Norton Basin or Hope Basin Planning Areas. 

None of the Bering Sea area is currently open for leasing. The North Aleutian Basin Planning Area 

currently is under Presidential withdrawal from leasing. The MMS is considering whether to request 

amendment of the withdrawal to allow the North Aleutian Basin Planning Area to be included in the 2007-

2012 5-year OCS leasing program. 

In the Beaufort Sea multiple-sale EIS (USDOI, MMS, 2003a), we stated that in the Canadian Beaufort Sea, 

the main area of industry interest has been around the Mackenzie River Delta and offshore of the 

Tuktoyaktuk Peninsula. This remains the case. Oil was discovered in these areas, although industry 

showed little interest in the area during the 1990’s. Interest in the area increased recently, and an openwater seismic-exploration program was conducted off the Mackenzie River Delta during late summer and 

autumn of 2001. This was the first major offshore seismic surveying program in that area since the early 

1990’s. GX Technology Corporation plans a similar seismic survey in late summer and autumn this year in 

the Mackenzie Delta of the Canadian Beaufort Sea. Section III.F.3(f)(6)(b) describes the study on the 

behavioral response of bowhead whales in feeding areas to the 2001 seismic survey (Miller and Davis, 

2002). Potential effects from the GX Technology Corporation survey could be similar. Some drilling 

operations may be conducted in the Canadian Beaufort Sea over the next few years. Bowhead whales 

migrate to and feed offshore of the Mackenzie River Delta region of the Canadian Beaufort Sea. Offshore 

development and production in this area likely would have greater potential to have adverse impacts on 

feeding bowhead whales than development elsewhere in the Beaufort Sea. 

In conclusion, available data do not indicate that noise and disturbance from oil and gas exploration and 

development activities since the mid-1970’s had a lasting population-level adverse effect on bowhead 

whales. Data indicate that bowhead whales are robust, increasing in abundance, and have been 

approaching (or have reached) the lower limit of their historic population size at the same time that oil and 

gas exploration activities have been occurring in the Beaufort Sea and, to a lesser extent, the Chukchi Sea. 

However, data are inadequate to fully evaluate potential impacts on whales during this period, including the 

duration of habitat use effects or numbers and types of individuals that did not use high-use areas because 

of the activities. Oil and gas exploration activities, especially during the 1990’s and early 2000’s have been 

shaped by various mitigating measures and related requirements for monitoring. Such mitigating measures, 

with monitoring requirements, were designed to, and probably did, reduce the impact on the whales and on 

potential impacts on whale availability to subsistence hunters. We assume future activities in Federal OCS 

waters will have similar levels of protective measures. However, we cannot be certain of what mitigating 

measures will be imposed in state waters or what the impacts of land-related support activities will be. We 

also note that the effectiveness of mitigations is not entirely clear, nor is it clear when, or if, the level of 

 PEA-211 
activity might become large enough to cause effects that are biologically significant to large numbers of 

individuals. Looking at each action separately indicates that there should not be a strong adverse effect on 

this population. Future activity in the OCS has the potential to contribute a substantial increase in noise 

and disturbance that will occur from oil and gas activities in state waters and on land as well as increase 

spill risk to this currently healthy population. It is not clear what the potential range of outcomes might be 

if multiple disturbance activities occur within focused areas of high importance to the whales. As we 

consult with NMFS over the next few months, we will continue to explore ways to determine the potential 

for cumulative impacts on these whales. 

Overall, the Proposed Action seismic surveys are likely to result in some incremental cumulative effects to 

bowhead whales through the potential exclusion or avoidance of bowhead whales from feeding or resting 

areas and disruption of important associated biological behaviors. However, the impact analysis of the 

likely range of effects and the likelihood of exposures resulting in adverse behavioral effects supports a 

conclusion that the activities would result in no more than temporary adverse effects and less than stocklevel effects. Mitigation measures included in the Selected Alternative (Sec. V) and those imposed through 

the MMPA authorizations process are designed to avoid Level A Harassment (injury), reduce the potential 

for population-level significant adverse effects on bowhead whales, and avoid an unmtigable adverse 

impact on their availability for subsistence purposes. We also developed additional measures to help 

reduce the level of uncertainty during the conduct of the seismic-survey activities, which provide yet 

another level of mitigation and protection. Therefore, MMS concludes that seismic surveys, especially as 

mitigated under the Proposed Action alternatives, are not expected to add significantly to the cumulative 

impacts on bowhead whales from past, present, and future activities. 

III.H.3.b Fin Whales. 

III.H.3.b(1) Past Commercial Hunting. Most stocks of fin whales were depleted by commercial whaling 

(Reeves, Silber, and Payne, 1998) beginning in the second half of the mid-1800’s (Schmitt, de Jong, and 

Winter, 1980; Reeves and Barto, 1985). In the 1900’s, hunting for fin whales continued in all oceans for 

about 75 years (Reeves, Silber, and Payne, 1998) (see information on whaling level in the previous section 

on current and historic abundance). It is likely that reports of Soviet takes of fin whales in the North 

Pacific are unreliable (Reeves, Silber, and Payne, 1998), because evidence indicates the Soviets overreported fin whale catches by about 1,200, presumably to hide takes of species such as right whales and 

other protected species (Doroshenko, 2000). In 1965, Nemoto and Kasuya (1965) reported that fin and sei 

whales were the primary species taken in the Gulf of Alaska during Japanese commercial whaling in recent 

catches. Figure 1 of that report documents that in 1963, more than 150 fin whales were taken just south of 

the Kenai Peninsula. Other areas of high take in 1963 were southeast Alaska especially and areas offshore 

between Prince William Sound and Glacier Bay. Multiple smaller groups of fin whales were taken 

offshore of areas south of Kodiak Island and the Alaska Peninsula to Unimak Pass, and large numbers were 

taken throughout the northern Gulf in an area bounded on the south at approximately 53° N. latitude. Legal 

commercial hunting ended in the North Pacific in 1976. 

III.H.3.b(2) Other Past, Present, and Foreseeable Human Impacts. Documented human-caused 

mortality of fin whales in the North Pacific since the cessation of whaling is low. There is no evidence of 

subsistence take of fin whales in the Northeast Pacific (Angliss, DeMaster, and Lopez, 2001; Angliss and 

Lodge, 2002). The NMFS (Angliss, DeMaster, and Lopez, 2001; Angliss and Lodge, 2002) summarized 

that “There are no known habitat issues that are of particular concern for this stock” (Angliss, DeMaster, 

and Lopez, 2001; Angliss and Lodge, 2002). Perry, DeMaster, and Silber (1999a:51) list the following 

factors possibly influencing the status of fin whales in the North Pacific: 

1. Offshore oil and gas development as a “Present or threatened destruction or modification of 

habitat” and 

2. Vessel collisions as an “Other natural or man-made factor.” 

The possible influences of disease or predation and of overutilization are listed as “Unknown.” 

Documented fishery interaction rates are low in the North Pacific. However, the only information available 

for many fisheries in the Gulf of Alaska comes from self reporting by individual fishers. Such data likely 

 PEA-212 
are biased downwards. Based on the death in 1999 of a fin whale incidental to the Bering Sea/Aleutian 

Island groundfish fishery, National Marine Fisheries Service estimates three mortalities in 1999 and an 

average yearly take of 0.6 [coefficent of variation (CV) = 1]) between 1995 and 1999 (Angliss and Lodge, 

2002). Based on the fact that there have not been known takes since that time, Angliss and Outlaw 

(2005:rev. 1/12/06) concluded that the total estimated mortality and serious injury incurred by this stock as 

a result of interactions with commercial fisheries is 0. Reported instances of fin whale deaths due to vessel 

strikes are low. In the North Atlantic, there is documented effect on behavior from whale watching and 

other recreational boat encounters and from commercial-vessel traffic (for example, Stone et al., 1992) and 

also evidence of habituation to increased boat traffic (Watkins, 1986). 

The North Aleutian Basin Planning Area currently is under Presidential withdrawal from leasing. The 

MMS is considering whether to request amendment of the withdrawal to allow the North Aleutian Basin 

Planning Area to be included in the 2007-2012 5-year OCS leasing program. The Bering Sea, including 

portions of the North Aleutian Basin Planning Area, is an area of high use by fin whales for feeding during 

many months of the year (see affected environment section). If oil and gas leasing and related activities 

occur, then fin whales could be exposed to the potential impacters referred to in the effects section of the 

bowhead whale. 

Overall, the Proposed Action seismic surveys are likely to result in some incremental contribution to effects 

on fin whales through the exclusion or avoidance of fin whales from feeding or resting areas and disruption 

of important biological behaviors. These effects would be limited in scope due to the low level of fin 

whale occurrence in the Proposed Action area. Mitigation measures included in the Selected Alternative 

(Sec. V) and imposed through the MMPA authorizations process are designed to avoid Level A 

Harassment (injury), reduce the potential for Level B Harassment (disturbance), and reduce the potential 

for adverse effects on whales. Therefore, the MMS concludes that seismic surveys, especially as mitigated 

under the Proposed Action alternatives, are not expected to add significantly to the cumulative impacts on 

fin whales from past, present, and future activities. 

III.H.3.c Humpback Whales. Commercial whale hunting resulted in the depletion and endangerment of 

humpback whales. Prior to commercial hunting, humpback whales in the North Pacific may have 

numbered approximately 15,000 individuals (Rice 1978b). . Unregulated hunting legally ended in the 

North Pacific in 1966. 

The NMFS (1991a) reports that entrapment and entanglement in active fishing gear (O’Hara, Atkins, 

Ludicello, 1986) as the most frequently identified source of human-caused injury or mortality to humpback 

whales. Entrapment and entanglement have been documented in Alaska (for example, von Zeigesar, 1984 

cited in von Ziegesar, Miller, and Dahlheim, 1994). From 1984-1989, 21 humpbacks are known to have 

become entangled in gear in Alaska. Gear types included gill nets, seine nets, long lines or buoy lines, and 

unidentified gear. 

Vessel collision also is of concern for humpbacks. The NMFS (1991a) reported that at least five 

photographed humpbacks in southeastern Alaska had gashes and dents probably caused by vessel strikes. 

The NMFS (1991a) also lists noise and disturbance from whale-watching boats; industrial activities; and 

ships, boats, and aircraft as causes of concern for humpback whales. The impact of pollution on 

humpbacks is not known. Habitat degradation also could occur due to coastal development. In Hawaii 

humpback habitat, harbor and boat-ramp construction, vessel moorings, water sports, increased boat traffic, 

dumping of raw sewage by boats, runoff and overflow of sewage from land sites, and agriculture and 

associated runoff are all potential causes of current habitat degradation. 

Based on the general category of factors specified as requiring consideration under the ESA, Perry, 

DeMaster, and Silber (1999b) listed the following factors as possibly impacting the recovery of humpbacks 

in the North Pacific: 

1. vessel traffic and oil and gas exploration as types of “Present or threatened destruction or 

modification of habitat”(Central Stock); 

 PEA-213 
2. whale watching, scientific research, photography, and associated vessel traffic as types of 

“Overutilization...” (Central Stock); and 

3. entanglement in fishing gear as “Other natural or man-made factors” (Central Stock). 

They list the threat of disease or predation as unknown. 

During 1990-2000, six commercial fisheries within the range of the both the western and central North 

Pacific stocks were monitored: Bering Sea/Aleutian Island and Gulf of Alaska groundfish trawl, longline, 

and pot fisheries. One humpback was killed in the Bering Sea/Aleutian Island groundfish trawl fishery in 

1998 and one in 1999. There are no records of humpbacks killed or injured in the fisheries in which fishers 

self report (Angliss and Lodge, 2002), but the reliability of such data is unknown. One entanglement is 

recorded in 1997 for a humpback in the Bering Strait (Angliss and Lodge, 2002). However, between 1996 

and 2000, five entanglements of humpbacks from the Central North Pacific Stock were reported in 

Hawaiian waters. Table 27b of Angliss and Lodge (2003:157) gives a total of 34 humpbacks from the 

Central North Pacific Stock classified as being involved in a human-related stranding or entanglement 

between 1997 and 2001. The Alaska Scientific Review Group (2001) stated that 32 humpbacks were 

entangled in southeast Alaska in the past 5 years. Vessel strikes cause significant mortality in humpbacks 

in the California/Oregon/Washington stock (an average of 0.6 killed per year) (Barlow et al., 1997) and in 

the western Atlantic (Perry, DeMaster, and Silber, 1999b). Perry, DeMaster, and Silber (1999b) reported 

that continued development of coasts and oil exploitation and drilling may lead to humpbacks avoidance of 

areas. In a Newfoundland inlet, two humpbacks with severe mechanical damage to their ears were found 

dead near a site of continued subbottom blasting (Ketten, Lien, and Todd, 1993; Lien et al., 1993; Ketten, 

1995). Perry, DeMaster, and Silber (1999b) summarized that humpbacks respond the most to moving 

sound sources (for example, fishing vessels, low-flying aircraft). Long-term displacement of humpbacks 

from Glacier Bay and parts of Hawaii may have occurred due to vessel-noise disturbance (see references in 

Perry, DeMaster, and Silber, 1999b) (see further discussion in Section IV.B.1.f). Due to concerns about the 

impacts of helicopters in Hawaiian waters, helicopters are prohibited from approaching within a slant range 

of 1,000 ft or 305 m from humpbacks (NMFS, 1987). Noise on their wintering grounds from the ATOC 

and the Navy’s Low-Frequency Active Sonar program also are sources of concern for the central North 

Pacific stock (Angliss and Lodge, 2002). No subsistence take of humpbacks is reported from Alaska or 

Russia (Angliss and Lodge, 2002). 

The North Aleutian Basin Planning Area currently is under Presidential withdrawal from leasing. The 

MMS is considering whether to request amendment of the withdrawal to allow the North Aleutian Basin 

Planning Area to be included in the 2007-2012 5-year OCS leasing program. The Bering Sea, including 

portions of the North Aleutian Basin Planning Area, is an area of high use by humpback whales for feeding 

during many moths of the year (see affected environment section). If oil and gas leasing and related 

activities occur, then humpback whales could be exposed to the potential impacters referred to in the effects 

section of the bowhead whale. Studies have documented that humpback whales, especially females with 

calves, respond to seismic survey noise (see Noise and Disturbance Effects section above). Todd et al. 

(1996) concluded that exposure of the humpbacks to deleterious levels of sound may have influenced 

entrapment rates. 

Potential cumulative effects on both the North Pacific stock and on the Western North Pacific stock warrant 

concern and monitoring. Overall, the Proposed Action seismic surveys are likely to result in some 

incremental contribution to effects on humpback whales through the exclusion or avoidance from feeding 

or resting areas and disruption of important biological behaviors. Mitigation measures included in the 

Selected Alternative (Sec. V) and imposed through the MMPA authorizations process are designed to avoid 

Level A Harassment (injury), reduce the potential for Level B Harassment (disturbance), and reduce the 

potential for adverse effects on humpback whales. Therefore, the MMS concludes that seismic surveys, 

especially as mitigated under the Proposed Action alternatives, are not expected to add significantly to the 

cumulative impacts on humpback whales from past, present, and future activities. 

 PEA-214 
III.H.4. Nonthreatened and Nonendangered Marine Mammals 

III.H.4.a. Air Traffic. The Proposed Action is expected to generate some aircraft traffic, as helicopters 

may be used to transport personnel and supplies to and from the seismic survey vessels and aerial 

monitoring may be required to monitor for the presence of bowhead whales. These activities are not 

expected to add significantly to the amount of commercial and recreational air traffic already existing in the 

Beaufort and Chukchi Seas during the period of the Proposed Action. 

The effects of air traffic on pinnipeds in the action area are expected to be local and transient in nature. 

Some groups of pinnipeds may be disturbed and leave their haulouts to enter the water, although their 

responses will be highly variable and brief in nature. Mitigation measures (See Section IV) prohibiting 

aircraft overflights of hauled out walrus below 1,000 ft will lessen aircraft impacts to these pinnipeds. 

The effects of air traffic on polar bears in the action area also are expected to be local and transient in 

nature. Polar bears often, but not always, run away from aircraft passing at low altitude. Their responses 

also will be highly variable and brief in nature. 

Richardson et al. (1995a) suggest that airborne sounds (and visual stimuli) from aircraft may be less 

relevant to toothed whales than baleen whales but reactions are variable. For example, beluga responses in 

offshore waters near Alaska ranged from no overt response to abrupt diving and avoidance, and generally 

increased with decreasing flight altitude. Reactions to aircraft include diving, tail slaps, or swimming away 

from the aircraft track. Gray whale mother-calf pairs seem to be sensitive, while migrating gray whale 

responses are not as detectable. In other cases, both baleen and toothed whales showed no reaction to 

aircraft overflights. In summary, responsiveness depends on variables, such as the animal’s activity at the 

time of the overflight or altitude level of aircraft, and most animals quickly resume normal activities after 

the aircraft has left the area. Richardson et al. (1995a) state that there is no indication that single or 

occasional overflights can cause long-term displacement of cetaceans. 

III.H.4.b. Climate Change. In the past decade, geographic displacement of marine mammal-population 

distributions has coincided with a reduction in sea ice and an increase in air and ocean temperatures in the 

Bering Sea (Grebmeier et al., 2006). As a result, between 1981 and 2002, gray whales relocated their 

primary foraging area from the Chirikov Basin, adjacent to the north shore of St. Lawrence Island, 

northward into the Chukchi Sea (Moore, Grebmeier, and Davies, 2003). Similar displacements of key 

walrus foraging areas could result from recent population declines of bivalves, the primary prey item of 

walrus, in the Bering Sea (Lovvorn et al., 2003). Continued warming is likely to increase the occurrence 

and resident times of subarctic species (spotted seals, walrus, and beluga whales) in the Chukchi and 

Beaufort seas. Negative effects on truly arctic species (polar bears, ringed seals, and bearded seals) also are 

likely to result from climate warming. Polar bears and ringed seals depend on sea ice for their life 

functions, and reductions in the extent and persistence of ice in the Beaufort and Chukchi seas almost 

certainly would have negative effects on their populations (USDOI, FWS, 1995). Climate change already 

has affected polar bears in Western Hudson Bay, where bears hunt ringed seals on the sea ice from 

November to July and spend the open-water season fasting on shore. In a long-term study, Stirling, Lunn, 

and Iacozza (1999) correlated decreased body condition and reproductive performance in bears with a trend 

toward earlier breakup of sea ice in recent years. The earlier breakup shortens the bears feeding season and 

increases the length of their fasting season. Ringed seals often give birth to and care for their pups on 

stable shorefast ice; therefore, changes in the extent and stability of shorefast ice or the timing of breakup 

could reduce their productivity. Because of the close predator-prey relationship between polar bears and 

ringed seals, decreases in ringed seal abundance can be expected to cause declines in polar bear populations 

(Stirling and Oritsland, 1995). 

Climate change also has been implicated in the mortality of marine mammals. In early May 2005, a 

powerful storm blew more than 40 kn for a 3-day period in the Bering Sea west of St. Lawrence Island. 

Because of the early break up of the pack ice and reduced sea-ice cover, the ocean in the immediate vicinity 

of Gambell was nearly ice free, which allowed enough fetch for large waves to form and concentrated 

migrating walrus herds onto small icefloes. The large waves generated by the storm broke over all but the 

largest ice floes in the area. Local hunters indicated that the herds were negatively impacted by the severe 

 PEA-215 
weather. After the storm, hunters reported seeing only one or two calves among hundreds of females and 

harvesting lactating females without calves. Walrus were so exhausted after the storm, that they would not 

leave the ice when the hunters approached them or even when animals on the same floe were harvested 

(USDOI, FWS, 2005). This event has negative implications for future walrus recruitment and reproductive 

success. Similarly, Monnett and Gleason (2006) reported unprecedented polar bear mortalities following a 

severe storm event in the Beaufort Sea in the fall of 2004. They attributed this phenomenon to longer 

open-water periods and reduced sea-ice cover. 

The main impacts of climate change on cetaceans would result from habitat changes (e.g., ice melting) that 

might impact prey migration, location, or availability as well as potentially impact existing migratory 

routes and breeding or feeding grounds. However, measurable changes to the climate and resulting effects 

on marine mammal habitat are not expected during the duration of the Proposed Action. In addition, the 

Proposed Action is not anticipated to affect climate change trends. 

III.H.4.c. Community Development. No significant community developments are foreseen in the 

nearshore environments of the Beaufort and Chukchi seas during the open-water period in 2006. The 

Proposed Action would add a slight amount of community development needs to support increased 

personnel and would involve mainly socioeconomic impacts. Community development activities are not 

expected to introduce any additional sounds into the action area during the proposed activities. 

III.H.4.d. Chemical Introduction (oil and fuel spills and industrial chemicals). Existing onshore and 

offshore facilities and their associated pipelines have the potential to release industrial chemicals or spill 

oil. However, environmental, safety, and operations procedures for these facilities and mitigation and 

monitoring requirements imposed in permits are designed to lessen the potential for oil and industrial 

chemicals to be introduced into the environment. 

Spilled oil can have a dramatic and lethal effect on marine mammals, as has been shown in numerous 

studies, and a major oil spill would have major effects on polar bears and seals. Durner and Amstrup 

(2000) modeled the spread of a hypothetical 5,900-bbl oil spill from the proposed Liberty development as it 

might affect the distribution and abundance of polar bears in the Beaufort Sea. The number of bears 

potentially affected by such a spill ranged from 0-25 in open-water conditions and 0-61with broken-ice 

conditions. The FWS concluded that, if such a spill occurred during the broken-ice period, a significant 

impact to polar bears could occur (65 FR 16833). It seems likely that an oil spill would affect seals in the 

arctic the same way the Exxon Valdez affected harbor seals (Frost et al., 1994) and the number of animals 

killed would depend largely on the season and size of the spill. As far as is known, however, marine 

mammals have not been affected by oil spilled as a result of North Slope industrial activities, although at 

least one polar bear fatality has resulted from ingestion of industrial chemicals (Amstrup, Myers, and 

Oehme, 1989). 

Although the effects are unknown, industrial development also has caused the development of a substantial 

amount of “arctic haze” in the Prudhoe Bay region, which likely precipitates into the marine environment 

as it drifts over the Arctic Ocean. 

Under the Proposed Action, the potential also exists for oil/fuel spills to occur from associated vessels. 

However, the risk is considered slight, and any spills that result from the Proposed Action most likely 

would be of small volume and are not considered a major threat to marine mammals in the action area. 

Even if a small oil/fuel spill were to occur, it would be easily avoidable by marine mammals. Any impacts 

to them most likely would include temporary displacement until cleanup activities are completed and shortterm effects on health from the ingestion of contaminated prey. 

III.H.4.e. Commercial and Recreational Fishing. Commercial and recreational fisheries in the Beaufort 

and Chukchi seas are very limited. 

III.H.4.f. Industrial Development and Related Noise. Oil- and gas-related and other industrial activities 

are anticipated during the 2006 open-water season in the Proposed Action area. This may include, but is 

not limited to artificial-island construction, operation of drilling barges (onshore and offshore), pipeline 

 PEA-216 
construction, seismic surveys, and vessel and aircraft operations. The largest issue for evaluation of 

impacts is the effect of noise produced from these activities on marine mammals. The main noiseproducing activities would include: (1) air-traffic noise; (2) construction; (3) drilling; (4) seismic surveys; 

and (5) vessel noise. The potential effects from these activities then must be considered in light of other 

existing noise levels within the Proposed Actions area (e.g., shipping noise, sounds of physical and 

biological environment) to determine if the Proposed Action and these additional noise impacts could 

cumulatively result in significant impacts to nonthreatened and nonendangered marine mammals. Details 

on source- and received-sound levels for many of these activities can be found in the MMS Biological 

Evaluation of the Potential Effects of Oil and Gas Leasing and Exploration in the Alaska OCS Beaufort Sea 

and Chukchi Sea Planning Areas on Endangered Bowhead Whales (Balaena mysticetus), Fin Whales 

(Balaenoptera physalus),and Humpback Whales (Megaptera novaeangliae) and Richardson et al., 1995a) 

and are considered in the analysis below. 

The main areas of concern regarding the effects on marine mammals of industrial development are the 

potential for contamination and for disturbance caused by industrial noise in the air and water. Although 

the effects are unknown, industrial development has caused the development of a substantial amount of 

arctic haze in the Prudhoe Bay region, which likely precipitates into the marine environment as it drifts 

over the Arctic Ocean. As far as is known, marine mammals have not been affected by oil spilled as a 

result of North Slope industrial activities, although at least one polar bear fatality has resulted from 

ingestion of industrial chemicals (Amstrup, Myers, and Oehme, 1989). Unfortunately, it has not been 

possible to predict the type and magnitude of marine mammal responses to the variety of disturbances 

caused by oil and gas operations and industrial developments in the Arctic. More importantly, it has not 

been possible to evaluate the potential effects on populations. 

During the 2006 open-water season, no construction of gravel islands is anticipated. One site, the 

Oooguruk field, will have armor (gravel bags) placed on the side slopes of its constructed gravel island. 

Construction of the Nikaitchuq field offshore gravel island in the Beaufort Sea has been permitted, but no 

work is planned for 2006. Otherwise, general maintenance can be expected on existing near shore and 

offshore islands. 

Drilling for oil and gas generally occurs from natural and artificial islands, caissons, bottom-founded 

platforms, and ships and submersibles. With varying degrees, these operations produce low-frequency 

sounds with strong tonal components. Drilling occurs once a lease has been obtained for oil and gas 

development and production and may continue through the life of the lease. 

Currently, there are no active offshore leases in the Chukchi and 181 active offshore leases in the Beaufort. 

However, drilling activities on these Beaufort leases for the 2006 open-water season are only expected to 

occur on the Northstar facility and within the Hammerhead leases and shoreline within the Point Thomson 

unit. Drilling in Sate waters is expected to be minimal. Other active drilling will take place on land but at 

sites away from coastlines. Given this information, the duration and frequency of drilling within cetacean 

habitat is anticipated to be minimal. Therefore, the combination of the Proposed Action and current or 

reasonably foreseeable drilling operations is expected to have a negligible impact on nonthreatened and 

nonendangered cetaceans in the Proposed Action area. 

Underwater sound from vessels operating near the Northstar facility in the Beaufort Sea often were 

detectable as far as 30 km offshore, while sounds from construction, drilling, and production reached 

background values at 2-4 km. BPXA began to use hovercraft in 2003 to access Northstar, which have 

proven to generate considerably less underwater noise than similar-sized conventional vessels and, 

therefore, may be an attractive alternative when there is concern over underwater noise (Richardson and 

Williams, 2004). Richardson and Williams (2004) concluded that there was little effect from the low-tomoderate level, low-frequency industrial sounds emanating from the Northstar facility on ringed seals 

during the open-water period, and that the overall effects of the construction and operation of the facility 

were minor, short term, and localized, with no consequences to the seal populations as a whole. 

The general impacts of seismic-survey noise on cetaceans are outlined in Sections III.F.3.f and III.F.3.g of 

this document. For the 2006 open-water season, 2D/3D seismic surveys for the oil and gas industry are 

 PEA-217 
expected to include offshore surveys under the Proposed Action (4 surveys in the Chukchi and 4 in the 

Beaufort) and one survey in State waters in the Beaufort. On-lease site-clearance surveys are expected to 

total three surveys in the Beaufort only. In addition, the University of Texas at Austin’s Institute for 

Geophysics plans to conduct a scientific seismic survey to collect seismic reflection and refraction data and 

sediment cores to reveal to crustal structure and composition of submarine plateaus in the western 

Amerasia Basin in the Arctic Ocean. Surveys will take place from the U.S. Coast Guard cutter Healy from 

mid-July to late August 2006. 

An assessment of the cumulative impacts of seismic surveys must then consider the decibel levels used, 

location, duration, and frequency of operations from the Proposed Action as well as other reasonably 

foreseeable seismic-survey activity. This information for the Proposed Action is contained in Section 

III.F.4.b (general impacts of seismic surveys on nonthreatened and nonendangered marine mammals). 

In general, the high-resolution, on-lease site-clearance seismic surveys are of lesser concern regarding 

impacts to cetaceans than the 2D/3D surveys. On-lease site-clearance surveys and 2D/3D seismic surveys 

do not occur in close proximity to each other, as they would interfere with each others’ information 

collection. This indirectly minimizes the potential for effects on nonthreatened and nonendangered 

cetaceans. 

For 2D/3Dseismic operations under the Proposed Action, MMS permits would require that vessels actively 

conducting seismic surveying maintain a minimum 15-mi distance from other seismic vessels. This is 

partly to avoid any cumulative effects from numerous vessels on the environment, but also to ensure data 

collection is not affected by the presence of other seismic-survey acoustic sources. In addition to the 

Proposed Action, one State-permitted seismic survey is anticipated in the Beaufort Sea, and a scientific 

seismic survey will take place from the Healy through the western Canadian Basin, Chukchi Borderland, 

and Mendeleev Ridge. The State-permitted survey would take place in nearshore waters. The Healy

operations would take place farther offshore than the surveys under the Proposed Action, except for the 

final leg of the Healy survey to an area due west of Barrow that may overlap. Although the exact timing of 

the Proposed Action seismic surveys is not known, it is believed they would not overlap temporally or 

spatially with this leg of the Healy operations. In this sense, the potential for significant cumulative 

impacts to cetaceans from all of the off-lease seismic surveying is limited through: (1) the required 15-mi 

separation for MMS-permitted surveys; (2) the mitigation and monitoring measures imposed for MMS 

permits (see Section IV); (3) requirements imposed under MMPA authorizations obtained by the seismic 

operators for mitigation to reduce impacts to species and subsistence; and (4) the expectation that these 

surveys would not coincide temporally or spatially. However, the potential for impacts to nonthreatened 

and nonendangered cetaceans exists from these survey activities. Therefore, the contribution of the 

Proposed Action to existing or reasonably foreseeable seismic activities is expected to have an adverse but 

not significant impact on nonthreatened and nonendangered marine mammals in the Proposed Action area. 

Past and future industrial developments along Alaska’s arctic coast undoubtedly will increase the number 

of polar bear-human conflicts that occur, as the frequency with which polar bears come into contact with 

people and structures undoubtedly is a function of the amount of activity in their habitats. Even with the 

best mitigation measures in place, it is certain that some bears will be harassed or killed. 

Industrial developments onshore also have the potential to disturb female polar bears in their maternal dens, 

where they are most sensitive to noise and vehicular traffic. Undisturbed denning habitat is critical to their 

reproductive success. More human activity along the coast and nearshore could reduce the suitability of 

some areas for use by denning female bears. 

Because the marine waters of the Beaufort and Chukchi seas have seen only limited and sporadic industrial 

activity, it is likely that there have been no serious effects or accumulation of effects on pinnipeds or 

fissipeds from industrial development in the Proposed Action area. Indeed, although it is difficult to 

accurately estimate marine mammal populations, mark-recapture studies of polar bears in the Beaufort Sea 

suggest that the population increased considerably between 1967 and 1998 (Amstrup, McDonald, and 

Stirling, 2001). 

 PEA-218 
Careful mitigation can help reduce the effects of future industrial developments and their accumulation 

through time. However, the effects of full-scale industrial development of the waters of the Chukchi and 

Beaufort seas likely would accumulate through displacement of polar bears and ringed seals from their 

preferred habitats, increased mortality, and decreased reproductive success. 

Noise introduced into the environment from industrial activities, including drilling and seismic operations, 

is expected to have an adverse but not significant impact on nonendangered and nonthreatened marine 

mammals. 

III.H.4.g. Vessel-Traffic Noise. Increasing vessel traffic in the Northwest Passage, which includes the 

Proposed Action area, increases the risks of oil and fuel spills and vessel strikes of marine mammals. The 

Proposed Action is not expected to contribute substantially to these risks, as seismic exploration will occur 

in ice-free seas and because most marine mammals will actively avoid close proximity to seismic 

operations. 

Vessel traffic in the Alaskan Arctic generally occurs within 20 km of coast and usually is associated with 

fishing, hunting, cruise ships, icebreakers, Coast Guard activities, and supply ships and barges. No 

extensive maritime industry exists for transporting goods. Traffic in the Beaufort and Chukchi seas at 

present is limited primarily to late spring, summer, and early autumn. 

For cetaceans, the main potential for effects from vessel traffic is through vessel strikes and acoustic 

disturbance. Given the low levels of vessel activity expected, the potential for vessel strikes on cetaceans is 

considered minimal. Regarding sound produced from vessels, it is generally expected to be less in shallow 

waters (i.e., background noise only by 10 km away from vessel) and greater in deeper waters (traffic noise 

up to 4,000 km away may contribute to background noise levels) (Richardson et al., 1995b). Aside from 

seismic-survey vessels, barging associated with activities such as onshore and limited offshore oil and gas 

activities, fuel and supply shipments, and other activities contributes to overall ambient noise levels in 

some regions of the Beaufort Sea. Whaling boats (usually aluminum skiffs with outboard motors) 

contribute noise during the fall whaling periods in the Alaskan Beaufort Sea. Fishing boats in coastal 

regions also contribute sound to the overall ambient noise. Sound produced by these smaller boats 

typically is at a higher frequency, around 300 Hz (Richardson et al., 1995b). 

Overall, the level of vessel traffic in the Proposed Action area, either from oil- and gas-related activities or 

other industrial, military or subsistence activities, is expected to be minimal. 

III.H.4.h. Other Noise Sources. Additional noise-producing activities are associated with some research, 

military, commercial, or other vessel use of the Beaufort or Chukchi seas. Such systems include multibeam sonars, sub-bottom profilers, acoustic Doppler current profilers, etc. Descriptions of examples of 

these types of acoustic sources are provided in LGL Alaska Research Assoc. and LGL Ltd., environmental 

research assoc. (LGL Ltd., 2005). 

The University of Texas at Austin’s Institute for Geophysics plans to conduct a scientific seismic survey to 

collect seismic reflection and refraction data and sediment cores to reveal to crustal structure and 

composition of submarine plateaus in the western Amerasia Basin in the Arctic Ocean. Surveys will take 

place from the U.S. Coast Guard cutter Healy from mid-July to late August 2006, with a focus on the 

western Canadian Basin, Chukchi Borderland and Mendeleev Ridge. Federally-permitted surveys would 

occur throughout the Beaufort and Chukchi seas. State-permitted survey would take place in nearshore 

waters. The Healy operations would take place farther offshore than the surveys under the Proposed 

Action, except for the final leg of the Healy survey to an area due west of Barrow that may overlap. 

Although the exact timing of the surveys is not known, it is believed they would not overlap temporally or 

spatially with this leg of the Healy operations. In this sense, the potential for significant cumulative 

impacts to cetaceans from all of the off-lease seismic is further limited through: (1) the required 15 mi 

separation for MMS-permitted surveys; (2) the mitigation and monitoring measures imposed for MMSpermits (see Section IV); (3) requirements imposed under MMPA authorizations obtained by the seismic 

operators for mitigation to reduce impacts to species and subsistence; and (4) the expectation that these 

surveys would not coincide temporally or spatially. 

 PEA-219 
On-ice seismic operations may occur in the Harrison Bay portion of the Beaufort Sea from March through 

May 20, 2006. This activity may impact bearded and ringed seals and polar bears. However, the area 

historically has had low ringed seal densities (Frost et al., 2004), and water depths in the majority of the 

planned survey area are <3 m (<10 ft), which is indicative of poor seal habitat. Bearded seals generally are 

associated with the pack ice and only rarely use shorefast ice. Because they normally are found in broken 

ice that is unsuitable for on-ice seismic operations, bearded seals likely would not be encountered during 

this activity, and any disturbance to them would be distant and transient in nature. Due to the low densities 

of ringed and bearded seals (the primary prey of polar bears) in this area, few if any polar bears also are 

likely to be encountered. Therefore the overall impact from winter seismic operations in this area to ringed 

and bearded seals and polar bears is expected to be negligible. 

III.H.4.i. Subsistence Harvest. Basic calculations indicate that annual subsistence harvest of ringed, 

spotted, ribbon, and bearded seals account for approximately 1.0%, 8.9%, 0.2%, and 2.7% of their lowest 

estimated Alaskan population sizes, respectively. For walrus, annual subsistence harvest is estimated to 

account for 2.9% of their total population. It should be noted, however, that due to the lack of recent and 

accurate population data, these are rough estimates only. 

The current status of the Chukchi stock of polar bears shared between Russia and the U.S. is in question. 

Russia prohibited polar bear hunting in 1956 in response to perceived population declines; however, both 

sport and subsistence harvest continued in Alaska until 1972. During the 1960’s, hunters took an average 

of 189 bears per year from the Chukchi Sea population, an unsustainable rate of harvest that likely caused 

significant population declines. With the passage of the Marine Mammal Protection Act (MMPA) in 1972, 

which prohibited sport hunting, the average annual Alaska harvest in the Chukchi Sea dropped to 67 bears 

per year. With the collapse of the Soviet empire in 1991, levels of illegal harvest dramatically increased in 

Chukotka. While the magnitude of the Russian harvest from the Chukchi Sea is not precisely known, some 

estimates place it as high as 400 bears per year, although the figure is more likely between 100-250 bears 

per year. Models run by the USDOI, FWS indicate that current levels of harvest in the Chukchi Sea most 

likely are unsustainable, and that an average annual harvest of 180 bears (4.5% of the starting population) 

could potentially reduce the population by 50% within 18 years (USDOI, FWS, 2003). This level of 

simulated harvest is similar to the estimated U.S./Russia annual harvest for the period 1992-2006, as well 

as to the unsustainable harvest levels experienced in Alaska in the 1960’s, indicating that the Chukchi stock 

of polar bears well may be in decline due to overharvest. These calculations were based on a starting 

population of 4,000 bears, which is believed to fairly characterize a healthy Chukchi Sea population. 

Compared to harvest levels from the 1980’s, Alaskan Native subsistence harvests of polar bears have 

declined substantially in the Chukchi Sea over the last decade. This decline may be due to a declining 

polar bear population, which provides fewer animals for harvest, changing environmental conditions, 

changing demographics among hunters resulting in decreased hunter effort, or a combination of these 

factors. 

In the Proposed Action area, there are lethal takes of beluga whales by Alaskan Natives for subsistence 

purposes. The Proposed Action is not expected to result in lethal takes of belugas. 

III.H.4.j. Military Activities. Current and foreseeable military activities in the Proposed Action area are 

not expected to be extensive; therefore, their potential to cause impacts to marine mammals is considered 

slight. 

In the past, individual marine mammals, particularly polar bears, likely were subjected to increased hunting 

pressure due to the military presence in the Arctic, particularly at the DEW-Line sites. However, sport 

hunting of marine mammals was banned with the passage of the MMPA in 1972, and polar bear 

populations are believed to have recovered in the subsequent 34 years. One male polar bear is known to 

have been killed in Defense of Life and Property in 1993 at the Oliktok DEW-Line station after it severely 

mauled a resident worker there. 

 PEA-220 
III.H.4k. Conclusions. Nonthreatened and nonendangered marine mammals may be affected by many 

factors, including climate change, community development, subsistence activities, air and vessel traffic, 

industrial noise, fisheries, and military activities. The MMS concludes that seismic surveys, especially as 

mitigated under the Proposed Action alternatives, are not expected to add significantly to the cumulative 

impacts on nonthreatened and nonendangered marine mammals from past, present, and future activities. 

III.H.5. Subsistence-Harvest Patterns. This section focuses on those activities and events that 

could introduce noise into the marine environment and potentially impact subsistence resources and 

activities during the 2006 open-water season. The main agents of the cumulative activities scenario are 

past, present and foreseeable: (1) marine seismic survey; (2) vessel traffic; (3) aircraft traffic; (4) oil and 

gas development in Federal, State, and Canadian waters; and (5) miscellaneous activities and factors and 

industrial development. 

III.H.5.a. Marine Seismic Surveys. Up to four marine seismic surveys could occur in both the Chukchi 

and Beaufort seas in 2006; in the Beaufort Sea OCS, up to three high-resolution site-clearance surveys also 

are expected on oil and gas prospects, and one MMS and one State permit are likely to be issued in 2006 

for ocean-bottom-cable (OBC) seismic survey in the Beaufort Sea. The MMS is aware of at least one nonoil- and gas-related scientific seismic survey that will be conducted in and near the Proposed Action area in 

2006. The University of Texas, Austin, with research funding from the National Science Foundation, plans 

to conduct a marine seismic survey in the western Canada Basin, Chukchi Borderland, and Mendeleev 

Ridge, Arctic Ocean, from July 15 to August 25, 2006. 

Given the growing interest of oil and gas companies to explore and develop oil and gas resources on the 

Arctic Ocean OCS, there is the potential that seismic surveys will continue in the Chukchi and Beaufort 

seas beyond 2006. Surveys beyond 2006 are dependent on: (1) the amount of data that is collected in 

2006; (2) what the data indicate about the subsurface geology; and (3) the results of Beaufort Sea Sale 202 

and Chukchi Sea Sale 193. Table III.C-1 provides information about the potential level and type of 

seismic-survey activities that may occur in the Beaufort and Chukchi seas between 2006 and 2010. 

Potential seismic-survey activity beyond 2006 will be addressed in the draft EIS for the OCS Oil and Gas 

Leasing Program, 2007 to 2012. 

III.H.5.b. Vessel Traffic and Movements. Aside from vessels associated with supporting the Proposed 

Action, vessel traffic in the Proposed Action area is limited. The majority of other vessels transiting 

through the Proposed Action area travel within 20 km of the coast would include, at a minimum, vessels 

used for fishing and hunting, cruise ships, icebreakers, Coast Guard vessels, supply ships, tugs, and barges 

that would include the seasonal supplying of local communities (usually one large fuel barge and one 

supply barge visit local villages each year); Prudhoe Bay sealifts (anywhere from 0-3 per year); West Dock 

vessel traffic for Northstar personnel (although crewboat traffic largely has been replaced by hovercraft and 

helicopter traffic) and resupply transport; barging for NPR-A drilling equipment; and, Canadian vessel 

traffic (LGL Alaska Research, 2006). 

Arctic marine transport in the Proposed Action area is likely to increase: from 1977 through 2005, there 

have been 61 North Pole transits (17 in the last year alone) and 7 trans-Arctic voyages (Brigham, 2005). 

Increased cargo transport in the Arctic (primarily outside the Chukchi and Beaufort seas area) also is 

expected due to increased petroleum and mining activities and the need for future supplies for these 

industries (PAME, 2000). 

III.H.5.c. Aircraft Traffic. Aircraft are used in the Beaufort and Chukchi seas for transporting supplies 

and personnel to local communities and industrial complexes (e.g., Deadhorse, Prudhoe Bay, Alpine, and 

Red Dog Mine), conducting research (e.g., marine mammal and marine bird surveys), recreation and 

tourism, monitoring weather and oceanographic conditions, and military exercises and surveillance. In 

2006, MMS will continue its annual bowhead whale aerial survey program, which usually begins 

September 1 and ends October 20. All surveys would be conducted at an elevation between 1,000 and 

1,500 ft. Other marine mammal research-related aerial surveys are likely to occur in the Arctic Ocean in 

2006, and possibly at elevations lower than 1,000 ft. The Proposed Action is expected to generate some 

 PEA-221 
aircraft traffic, as helicopters may be used to transport personnel and supplies to and from the seismicsurvey vessels. 

III.H.5.d. Oil and Gas Development in Federal, State, and Canadian Waters. In 2006, Pioneer 

Natural Resources Co. will begin the development of its North Slope Oooguruk field, which is in the 

shallow waters of the Beaufort Sea approximately 8 mi northwest of the Kuparuk River unit. Pioneer will 

begin construction in the winter of 2006 by installing an offshore gravel drilling and production site as soon 

as an ice road is completed, which will be used to haul gravel to the construction site. Some open-water 

activities in summer 2006 will involve placing armor (gravel bags) on the side-slopes of the constructed 

gravel island to protect it from erosion. 

In Canadian waters, Devon Canada Corporation is planning to do exploratory drilling off the Mackenzie 

River Delta in August 2006 GX Technology Corporation will conduct a 2D seismic survey in the 

Mackenzie River Delta area in late summer and fall. 

III.H.5.e. Miscellaneous Activities, Factors, and Industrial Development. On the Chukchi Sea, west of 

the North Slope industrial complex and outside the southern boundary of the Proposed Action area, the 

major industrial developments have been and continue to be associated with Red Dog Mine and the Delong 

Mountain Terminal (DMT). These facilities are included in the cumulative activities scenario, because 

about 250 barge lightering trips per year are needed to transfer 1.5 million tons of concentrate to bulk cargo 

ships anchored 6 mi offshore. About 27 cargo ships are loaded each year. These activities have the 

potential to affect the PEA’s biological resources of concern (e.g., marine mammals and marine birds) that 

migrate just offshore of the facilities into the marine waters of the Proposed Action area.. 

III.H.5.f. Effects of Noise and Traffic Disturbances. Seismic-exploration activity would increase 

somewhat under the cumulative scenario, but impacts to subsistence resources or practices are not expected 

to increase over those already described for the Proposed Action. Other noise and traffic disturbance from 

offshore facilities may affect marine-subsistence activities. In the cumulative case, the increased amount of 

oil-related traffic makes it likely that subsistence-harvest activities could be disrupted occasionally by boat 

and air traffic. Because most marine-hunting activity occurs within a wide area of open water, such 

interruptions typically may cause boat crews to hunt longer or take extra trips but are not expected to 

significantly reduce overall harvests of marine mammals or seabirds. The one exception could be walrus 

where, in recent years, local hunters have noted that the abundance of walrus in retreating spring pack ice 

has declined coincidental with the appearance of large tugs pulling supply barges (USDOI, FWS, 2006). 

Because of their short and ice-condition-dependent seasons, bowhead whale harvests are more likely to be 

affected by noise and traffic disturbance than are other forms of marine mammal hunting (other than beluga 

whaling). Because the bowhead whale harvest in all communities except Barrow tends to be quite small—

one to two whales per year—noise disturbance from icebreakers and other vessels could cause this small 

harvest to become locally unavailable for the entire season. Such activities already occasionally have 

affected subsistence hunting. For example, Kaktovik whalers stated that their 1985 fall whaling season was 

adversely affected by vessels related to oil development operating in open-water areas. Effects from noise 

and disturbance on the beluga whale harvest could increase under the cumulative scenario. Increased air 

traffic and vessel activities in the Chukchi Sea could impact the beluga harvest by causing beluga whales to 

become locally unavailable for certain critical periods. 

Access to subsistence resources and subsistence-hunting areas and the use of subsistence resources could 

change if cumulative noise and traffic disturbance reduces the availability of resources or alters distribution 

patterns. Cumulative effects to bowhead whales are a serious concern. If increased noise affected whales 

and caused them to deflect from their normal migration route, they could be displaced from traditional 

hunting areas, and the traditional bowhead whale harvest could be adversely affected. Historically, 

bowhead whales have been exposed to multiple sources of human-caused noise disturbance and are likely 

to be exposed to similar sources of noise disturbance in the foreseeable future, but required protective 

mitigation is expected to reduce these noise disturbance impacts. 

 PEA-222 
In any areas where the subsistence hunt could be affected, stipulations, required mitigation, and conflict 

avoidance-type measures under IHA requirements, as defined by NMFS and FWS, have, in the past, 

worked toward avoiding unreasonable conflicts or disturbance to subsistence activities and have required 

operators to demonstrate that no unmitigable adverse impacts occur to subsistence resources and practices. 

Conflict avoidance agreements between operators and the AEWC ensure that seismic operations are 

seasonally timed and monitored to prevent conflicts with the bowhead whale migration and the subsistence 

hunt. 

Limited monitoring data of past activities prevents effective assessment of subsistence-resource damage; 

resource displacement; changes in hunters’ access to resources; increased competition; contamination 

levels in subsistence resources; harvest reductions; or increased effort, risk, and cost to hunters. We cannot 

project effects properly without monitoring harvest patterns and the effectiveness of mitigation measures. 

Monitoring must include serious attention to traditional Inupiat knowledge of subsistence resources and 

practices. Development already has caused increased regulation of subsistence hunting, reduced access to 

hunting and fishing areas, altered habitat, and intensified competition from nonsubsistence hunters for fish 

and wildlife (Haynes and Pedersen, 1989). These trends show why monitoring of subsistence resources 

and harvests is important. 

III.H.5.g. Native Views Concerning Cumulative Effects on Subsistence-Harvest Patterns. 

III.H.5.g(1) Nuiqsut’s Views on Cumulative Effects. Cumulative effects from oil development have 

been, and continue to be, paramount concerns for North Slope residents. Sam Taalak, Nuiqsut’s Mayor in 

1982, saw the onslaught of cumulative activity 18 years ago: “We presently live at Nuiqsut and for the 

moment we’re hemmed in from all sides by major oil explorations, even from the coast front” (Taalak, 

1983, as cited in USDOI, MMS, 1983). Leonard Lampe, another former Mayor of Nuiqsut, noted that the 

village has begun to consider the long-term effect of oil development on their subsistence lifestyle and 

Inupiat culture: “It’s time to look at things seriously and ask if it’s worth it. That’s what the town is asking 

itself” (Lavrakas, 1996). 

Thomas Napageak, Nuiqsut Native Village President and Chairman of the AEWC, recently clarified some 

of these concerns. In a January 10, 1997, meeting with MMS in Anchorage over a possible Nuiqsut 

Deferral for Sale 170, Mr. Napageak explained that the people of Nuiqsut have begun to focus on 

cumulative effects because they are concerned that when the Northstar resources for 15-20 years. Such 

development directly affects Nuiqsut. Mr. Napageak wanted Sale 170 stipulations to deal with cumulative 

effects from the sale, and from other projects, and clear language about cumulative effects in the EIS. He 

wanted to see protective language developed for leases in the Sale 170 area that would extend to, and bind 

lessees with, leases from past sales (Casey, 1997, pers. commun.). 

At a scoping meeting in Nuiqsut for the Northeast NPR-A Integrated Activity Plan (IAP) EIS, Mr. 

Napageak noted again the importance of assessing cumulative effects on subsistence resources and 

harvests, especially the cumulative and indirect effects of existing and potential oil development on 

Nuiqsut. He remarked: “Federal leasing cannot be examined in isolation as though none of this other 

development and potential development were going on” (USDOI, BLM, 1997a). At a BLM symposium on 

the NPR-A held later the same month, he reaffirmed this concern: “Accumulated impact effects that would 

hinder the community and the socioeconomics of the community, how it will be affected by Alpine and 

presumably by NPR-A, these...really need to be considered” (Napageak, as cited in USDOI, BLM, 1997b). 

At an information update meeting in November 1999 for the Liberty Development Project, Elders Ruth 

Nukapigak and Marjorie Ahnupkana reaffirmed local concern for ongoing effects from oil development, 

saying that Eskimo traditions of long ago were going away with the oil companies coming in (Ahnupkana, 

as cited in USDOI, MMS, 1999). 

III.H.5.g(2) Kaktovik’s Views on Cumulative Effects. Kaktovik resident Michael Jeffrey, testifying for 

the first MMS lease sale of offshore oil and gas, saw a social impact from government actions. He said 

there was a cumulative effect on the villagers from having to participate in hearings and meetings. People 

knew the issues were important, so they had to take time off from working and hunting to attend. Jeffrey 

believed assessment documents are too technical. To help villagers with them, he suggested extending 

 PEA-223 
deadlines in communities that do not speak English, so there would be enough time for agencies to translate 

documents (Jeffrey, 1979, as cited in USDOI, BLM, 1979b). 

III.H.5.g(3) Barrow’s Views on Cumulative Effects. The North Slope Borough sent written scoping 

comments and recommendations on the BLM’s Northeast NPR-A IAP in April 1997. Their comments 

articulated concerns about potential effects to subsistence hunting and: 

...about the cumulative impacts of all industrial and human activities on the North Slope and its 

residents. Consideration of these impacts must take into account industrial activities occurring 

offshore and at existing oil fields to the east; scientific research efforts; sport hunting and 

recreational uses of lands; and the enforcement of regulations governing the harvest of fish and 

wildlife resources by local residents. To date, no agency has addressed the concerns of Borough 

residents over how cumulative impacts might affect life on the North Slope (North Slope Borough, 

1997). 

Barrow Mayor Ben Nageak, spoke at public hearings for the NPR-A IAP/EIS in Barrow in January 1997. 

He said one of the key issues in developing the Reserve was to identify “a mechanism for recognizing and 

mitigating the potential cumulative impacts of multiple industrial operations” (Nageak, as cited in USDOI, 

BLM, 1997b). At a Liberty Development Project information update meeting in November 1999, Ron 

Brower, head of the Inupiat Heritage Center in Barrow, asked about future leasing and development plans 

and noted that MMS seemed to be doing projects piece by piece when instead it should be studying 

cumulative impacts. He believed new data and new development projections were needed and wanted to 

see a “new blueprint [for development] from aerial flights to underwater impacts” (Brower, as cited in 

USDOI, MMS, 1999). At the same meeting, Maggie Ahmaogak, Executive Director of the Alaska Eskimo 

Whaling Commission, asked that MMS take into account cumulative risks. 

III.H.5.g(4). Chukchi Sea Communities’ Views on Cumulative Effects. Native bowhead and beluga 

whale hunters in communities in the Chukchi Sea region maintain that they, too, will be affected if 

important marine mammals are harmed. Just as in the Beaufort Sea communities of Barrow, Nuiqsut, and 

Kaktovik, the potential tainting of bowhead and beluga whales and seals, in any portion of their respective 

ranges and habitats, could taint these culturally important resources. Even if these species were available 

for the spring and fall seasons, traditional cultural concerns of tainting could make them less desirable and 

alter or stop subsistence harvests. 

The disruption of bowhead whale harvests could result from any potential diversion of the whale migration 

further offshore, or from other behavior changes by the animals—making them more skittish, for 

example—in reaction to OCS activities. The greater the degree of activity onshore and on the OCS, as 

measured by increases in seismic noise, vessel traffic, east-to-west development, increased activity in the 

Chukchi Sea, Canadian activities in the Mackenzie Delta, or some other metric, the more probable and 

more pronounced cumulative effects are likely to be. To a large extent, stipulations, required mitigation, 

and conflict avoidance agreements between subsistence whalers and oil operators have mitigated such 

potential effects and may continue to do so. 

III.H.5.h. Climate Change. Because of rapid and long-term impacts from climate change on longstanding traditional hunting and gathering practices that promote health and cultural identity, and 

considering the limited capacities and choices for adaptation and the ongoing cultural challenges of 

globalization to indigenous communities, communities in the Arctic could experience significant cultural 

stresses in addition to major impacts on population, employment, and local infrastructure. If subsistence 

livelihoods are disrupted, communities in the Arctic could face increased poverty, drug and alcohol abuse, 

and other social problems (Langdon, 1995; Peterson and Johnson, 1995; National Assessment Synthesis 

Team, 2000; IPCC, 2001c; Callaway et al., 1999; ARCUS, 1997). 

If the present rates of climate change continue, changes in diversity and abundance to arctic flora and fauna 

could be significant. Because polar marine and terrestrial animal populations would be particularly 

vulnerable to changes in sea ice, snow cover, and alterations in habitat and food sources brought on by 

climate change, rapid and long-term impacts on subsistence resources (availability), subsistence-harvest 

 PEA-224 
practices (travel modes and conditions, traditional access routes, traditional seasons and harvest locations), 

and the traditional diet could be expected (Johannessen, Shalina, and Miles, 1999; IPCC, 2001c; NRC, 

2003). 

III.H.5.i. Conclusion. Seismic surveys, especially as mitigated under the Proposed Action alternatives, 

would not be expected to add significant impacts to overall cumulative effects on subsistence-harvest 

resources and harvest practices from past, present, and future activities. 

III.H.6. Sociocultural Systems. Cumulative effects on sociocultural systems include effects of 

seismic activity during the 2006 open-water season in the action area and other past, present, and 

reasonably foreseeable projects in the Chukchi and Beaufort seas. Cumulative effects on sociocultural 

systems would come from changes to subsistence-harvest patterns, social organization and values, and 

other issues, such as stress on social systems. Potential effects could be experienced by the Inupiat 

communities of Kaktovik, Nuiqsut, Barrow, Atqasuk, Wainwright, Point Lay, and Point Hope (see Impact 

Assessment Inc., 1990a,b,c; 1998; Human Relations Area Files, Inc., 1994; State of Alaska, Dept. of Fish 

and Game, 1995b). 

III.H.6.a. Social Organization and Cultural Values. Because of the limited magnitude of the Proposed 

Action, significant changes to social organization and cultural values, such as stress on social systems due 

to changes in population and employment, are not expected to occur. On the other hand, potential 

significant impacts could result from changes to subsistence-harvest patterns. Such potential cumulative 

effects on subsistence-harvest patterns would affect Inupiat social organization through disruptions to 

kinship ties, sharing networks, task groups, crew structures, and other social bonds. 

Adverse affects on sharing networks and subsistence-task groups could break down family ties and the 

communities’ well-being, creating tensions and anxieties that could lead to high levels of social discord. 

The NSB’s institutional infrastructure, the AEWC, community whaling organizations, regional and tribal 

governments, and regional and village corporations work diligently to develop programs to protect these 

cultural values. The NSB, the AEWC, and local whalers have set precedents for negotiating agreements 

with the oil industry to protect subsistence-whaling practices. Such cooperation is expected to continue 

(Impact Assessment Inc., 1990a,b,c, 1998; Human Relations Area Files, Inc., 1995; State of Alaska, Dept. 

of Fish and Game, 1995b). 

Some of the vectors of sociocultural change that have been commonly noted in studies of arctic Alaska 

(Klausner and Foulks, 1982; Kruse et al., 1983a,b; Galginaitis et al., 1984; Luton, 1985; Worl and Smythe, 

1986; Kevin Waring Associates, 1988; Chance, 1989; Impact Assessment, Inc., 1989a,b; Jorgensen, 1990; 

Human Relations Area Files, 1992), lease sale documents (USDOI, MMS, 1990b, 1996a, 1998, 2001), or 

testimony during the lease sale process (numerous USDOI documents, 1978 to the present time) can be 

briefly summarized as follows: 

• Changes in community and family organization (availability of wage labor opportunities locally or 

regionally, ethnic composition, factionalism, household size); 

• Institutional dislocation and continuity (introduction of new institutions, “loss” or de-emphasis of older 

or more traditional ones, and adaptation of new forms to old content or values, and vice versa); 

• Changes in the pattern of overall subsistence activity (time allocation, equipment and monetary needs) 

and the potential disruption of subsistence harvest activities by industrial development; 

• Changes in health measures, which are a combination of increased access to health care, changes in 

diet, increased exposure to disease, substance use and abuse, concern over possible exposure to 

contaminants of various sorts, and perhaps other factors; 

• Perceived erosion of cultural values and accompanying behaviors (increased social pathologies such as 

substance abuse, suicide, and crime/delinquency in general; decreased fluency in Native languages; 

decreased respect for Elders; less sharing); and 

• Cultural “revitalization” efforts such as dance groups, Native language programs, and official and 

regular traditional celebrations (such as the reestablishment of Kiviaq, or the Messenger Feast, in the 

NSB). 

 PEA-225 
While these are all in some sense generalizations and “analytical constructs,” all are supported also by 

specific testimony of Native residents of the region. These dynamics are not generally viewed as oil and 

gas (let alone OCS) development specific, but rather as the overall context within which Inupiat culture 

must continue to exist. 

More specifically, OCS activities could affect subsistence (and thus sociocultural systems) in a potentially 

major way. Lease stipulations should mitigate many of these effects to the degree discussed in the 

subsistence section. Because subsistence is to a large extent the ideological idiom of Inupiat (and Alaskan 

Native) culture, this is a fundamental and important category of potential effects and extends very broadly. 

Increases in seismic activity in the Beaufort Sea, and the reinitiation of seismic exploration in the Chukchi 

Sea are significant vectors for potential effects. 

Because of rapid and long-term impacts from climate change on long-standing traditional hunting and 

gathering practices that promote health and cultural identity, and considering the limited capacities and 

choices for adaptation and the ongoing cultural challenges of globalization to indigenous communities, 

Arctic communities could experience significant cultural stresses in addition to major impacts on 

population, employment, and local infrastructure. If subsistence livelihoods are disrupted, communities in 

the Arctic could face increased poverty, drug and alcohol abuse, and other social problems (Langdon, 1995; 

Peterson and Johnson, 1995; National Assessment Synthesis Team, 2000; IPCC, 2001; Callaway et al., 

1999; ARCUS, 1997). 

If the present rates of climate change continue, changes in diversity and abundance to arctic flora and fauna 

could be significant. Because polar marine and terrestrial animal populations would be particularly 

vulnerable to changes in sea ice, snow cover, and alterations in habitat and food sources brought on by 

climate change, rapid and long-term impacts on subsistence resources (availability), subsistence-harvest 

practices (travel modes and conditions, traditional access routes, traditional seasons and harvest locations), 

and the traditional diet could be expected (Johannessen et al., 1999; IPCC, 2001b; NRC, 2003). 

In this cumulative analysis, effects on social institutions (family, polity, economics, education, and 

religion) could result from changes in subsistence-harvest patterns. Seismic surveys, especially as 

mitigated under the Proposed Action alternatives, would not be expected to add significant impacts to 

overall cumulative effects on subsistence resources and harvest practices from past, present, and future 

activities. Protective mitigation measures and conflict avoidance-type measures under IHA requirements 

incorporated into seismic survey permits reduce potential impacts on subsistence resources and harvest 

practices; thus, consequent impacts to sociocultural systems would be reduced. 

III.H.7. Environmental Justice. Alaskan Inupiat Natives, a recognized minority, are the 

predominant residents of the North Slope and Northwest Arctic Boroughs, the areas potentially most 

affected by activities assessed in the Arctic Seismic PEA. Cumulative effects on Inupiat Natives could 

occur because of their reliance on subsistence foods, and impacts from noise and vessel traffic from past, 

present, and foreseeable activities in the Chukchi and Beaufort Seas could affect subsistence resources and 

harvest practices. The EIS defines “significant” effects on environmental justice as: disproportionate, high 

adverse impacts to low-income and minority populations. Potential effects could be experienced by the 

Inupiat communities of Kaktovik, Nuiqsut, Barrow, Atqasuk, Wainwright, Point Lay, and Point Hope. 

Inupiat Natives could be disproportionately affected because of their reliance on subsistence foods; and 

actions under this PEA could affect subsistence resources and harvest practices. Stipulations, required 

protective mitigation measures, and conflict avoidance measures under IHA requirements would serve 

collectively to mitigate disturbance effects on Native lifestyles and subsistence practices and likely would 

mitigate any consequent impacts on sociocultural systems. These measures would reduce the potential for 

adverse effects on subsistence-harvest patterns, sociocultural systems, and environmental justice. The 

above mitigating measures incorporate traditional knowledge and the cooperative efforts between MMS, 

the State, the people of the North Slope, and tribal and local governments. Effects to environmental justice 

are expected to be mitigated substantially but not eliminated. The IHA process requires that operators 

 PEA-226 
demonstrate that their action will cause no unmitigable adverse impacts on subsistence uses of marine 

mammals. 

The MMS acknowledges sociocultural cumulative impacts on the North Slope and that Inupiat culture has 

undergone significant change. The influx of money and a changing landscape due to wage employment has 

added many benefits and raised the standard of living, but these influences also have given rise to an array 

of social pathologies that include increased alcoholism. However, cumulative effects are difficult to 

separate and, by far, most cumulative effects result from onshore development, as the oil patch spreads 

outward from Prudhoe Bay/Deadhorse. 

One point that was made numerous times at a Research Design Workshop for the Bowhead Whale 

Subsistence Hunt and OCS Oil and Gas Activities convened by MMS in April 2001 in Anchorage, was that 

any realistic analysis of cumulative effects on the North Slope needs to consider both onshore and offshore 

effects. To date, the most obvious cumulative effects have occurred and continue to occur onshore, 

although no adequate monitoring or comprehensive baseline data gathering has ever been undertaken 

onshore by responsible Federal and State agencies and industry. Most of the stress factors mentioned by 

local stakeholders normally can be associated with onshore impacts. Until a serious onshore-monitoring 

program is developed, causal linkages to impacts from onshore or offshore sources will be problematic. 

For a discussion of proposed mitigation measures and other ongoing mitigating initiatives that relate to 

environmental justice concerns, see Section III.G.6. While the projects discussed in Section III.G.6 in 

themselves would not resolve the larger problems of ongoing cultural challenge to Inupiat traditions from 

increasing development in the region and from the powerful influences of modernity, such as cable 

television, the Internet, and an increasing dependence on a wage-based economy, they provide processes 

for information sharing and opportunities for mutual decisionmaking and remediation of cumulative social 

and subsistence impacts. 

Potential impacts on human health from contaminants in subsistence foods and long-term climate change 

impacts on marine and terrestrial ecosystems in the Arctic—affecting subsistence resources, traditional 

culture, and community infrastructure of subsistence-based indigenous communities in the North Slope and 

Northwest Arctic Boroughs—would be an expected and additive contribution to cumulative environmental 

justice impacts. Potential disproportionately high adverse effects on low-income, minority populations in 

the region effects are expected to be mitigated substantially but not eliminated. Seismic surveys, especially 

as mitigated under the Proposed Action alternatives, would not be expected to add significant impacts to 

overall cumulative effects on subsistence-harvest resources and harvest practices from past, present, and 

future activities. 

III.H.8. Archaeological Resources. The greatest cumulative effect on archaeological resources in 

the Beaufort Sea and Chukchi Sea region is from natural processes such as ice gouging, bottom scour, and 

thermokarst erosion. Because the destructive effects of natural processes are cumulative, they have 

affected and will continue to affect archaeological resources in this area. These natural processes would 

cause artifacts to be dispersed and the site context to be disturbed or even completely destroyed, resulting 

in the loss of archaeological information. Overall, a significant loss of data from submerged and coastal 

prehistoric sites probably has occurred, and will continue to occur, from the effects of natural geologic 

processes in the Beaufort and Chukchi Sea region. It is assumed that some of the data lost have been 

significant and/or unique, resulting in a major level of impact. 

Ocean-bottom-cable seismic surveys potentially could impact both prehistoric and historic archaeological 

resources in waters inshore of the 20-m isobath or in deeper water, if cables are laid from shallow to deep 

water. Such offshore seismic-exploration activities evaluated in this PEA could disturb these resources and 

their in situ context. Assuming compliance with existing Federal, State, and local archaeological 

regulations and policies and the application of MMS’ G&G Permit Stipulation 6 (regarding the discovery 

of archaeological resources) and CFR 251.6 (a) (5) regarding G&G Explorations of the Outer Continental 

Shelf to not “disturb archaeological resources,” most impacts to archaeological resources in shallow 

offshore waters of the Beaufort Sea Planning Area would be avoided. Therefore, no impacts or only minor 

 PEA-227 
impacts to archaeological resources are anticipated; cumulatively, proposed projects are not likely to 

disturb the seafloor. 

Under the cumulative scenario, the impact to both prehistoric and historic archaeological sites should be 

negligible. The incremental contribution of the Proposed Action to the cumulative impacts on 

archaeological resources should be negligible. 

 PEA-228 
IV. SUMMARY OF FINDINGS, MITIGATION MEASURES, 

AND RECOMMENDATIONS 

The Minerals Management Service (MMS) has documented that the Beaufort and Chukchi seas support a 

wide variety of fish and wildlife resources, many of which support the Inupiat community’s subsistenceharvest culture and lifestyle. The conclusion generated by MMS’ collective analysis of the Proposed 

Action and alternatives (contained in Section III) indicates that operating high-energy acoustic equipment, 

i.e., airguns, in the marine environment has the potential to cause adverse environmental impacts on the 

proposed project area’s biological resources. For example, marine mammals could be harassed and 

possibly harmed by the acoustic environment generated around the airgun source. Any potential adverse 

effects on marine mammals also might adversely impact subsistence activities that rely on marine 

mammals. Marine birds, although not thought to be directly injured by the generated sounds of an airgun, 

potentially could be harassed away from feeding and resting areas by the acoustic sounds and repeated 

vessel and aircraft movements. Fish and fishery resources might be harassed away or blocked from desired 

spawning and feeding habitat under certain circumstances, and shellfish potentially could be harmed 

directly by the high-energy sound source. 

IV.A. Mitigation Measures Incorporated into the Alternatives. 

All seismic-survey operations in the Beaufort and Chukchi seas will be required to comply with MMS 

regulations governing geological and geophysical (G&G) explorations of the outer continental shelf (OCS) 

(30 CFR 251 Parts 1–15). The following protective measures (Secs. IV.A.1 and IV.A.2) for marine 

mammals already are incorporated into Alternatives 3, 4, 5, and 6 and would be incorporated in all MMSpermitted seismic activities considered under this Programmatic Environmental Assessment (PEA). 

IV.A.1. Standard MMS G&G Permit Stipulations. The following stipulations (see also 

Appendix A) are standard for MMS-permitted seismic activities and would be included for all seismic 

activities considered under this PEA: 

• No solid or liquid explosives shall be used without specific approval. 

• Operations shall be conducted in a manner to ensure that they will not cause pollution, cause 

undue harm to aquatic life, create hazardous or unsafe conditions, or unreasonably interfere with 

other uses of the area. Any difficulty encountered with other uses of the area or any conditions 

that cause undue harm to aquatic life, pollution, or could create a hazardous or unsafe condition as 

a result of the operations under this permit shall be reported to the Regional Supervisor/Field 

Operations. Serious or emergency conditions shall be reported without delay.

• Operators must maintain a minimum spacing of 15 miles between the seismic-source vessels for 

separate operations. The MMS must be notified by means of the weekly report whenever a shut 

down of operations occurs in order to maintain this minimum distance. 

• Permit applicants shall use the lowest sound levels feasible to accomplish their data-collection 

needs. 

• Vessels and aircraft should avoid concentrations or groups of whales. Operators should, at all 

times, conduct their activities at a maximum distance from such concentrations of whales. Under 

no circumstances, other than an emergency, should aircraft be operated at an altitude lower than 

1,000 feet when within 500 lateral yards of groups of whales. Helicopters may not hover or circle 

above such areas or within 500 lateral yards of such areas. 

• When weather conditions do not allow a 1,000-foot flying altitude, such as during severe storms or 

when cloud cover is low, aircraft may be operated below the 1,000-foot altitude stipulated above. 

However, when aircraft are operated at altitudes below 1,000 feet because of weather conditions, 

the operator must avoid known whale-concentration areas and should take precautions to avoid 

flying directly over or within 500 yards of groups of whales. 

• When a vessel is operated near a concentration of whales, the operator must take every precaution 

to avoid harassment of these animals. Therefore, vessels should reduce speed when within 300 

yards of whales and those vessels capable of steering around such groups should do so. Vessels 

 PEA-229 
may not be operated in such a way as to separate members of a group of whales from other 

members of the group. 

• Vessel operators should avoid multiple changes in direction and speed when within 300 yards of 

whales. In addition, operators should check the waters immediately adjacent to a vessel to ensure 

that no whales will be injured when the vessel’s propellers (or screws) are engaged. 

• Small boats should not be operated at such a speed as to make collisions with whales likely. 

When weather conditions require, such as when visibility drops, vessels should adjust speed 

accordingly to avoid the likelihood of injury to whales. 

• When any Permittee becomes aware of the potentially harassing effects of operations on 

endangered whales, or when any Permittee is unsure of the best course of action to avoid 

harassment of endangered whales, every measure to avoid further harassment should be taken until 

the NMFS is consulted for instructions or directions. However, human safety will take precedence 

at all times over the guidelines and distances recommended herein for the avoidance of 

disturbance and harassment of endangered whales. 

IV.A.2. Measures to Mitigate Seismic Exposure to Marine Mammals. The measures 

outlined below are based on: (1) the measures in the July 1999 and August 2001 incidental harassment 

authorizations (IHA’s) from NMFS for marine geophysical permits in the Beaufort Sea OCS; (2) the 

protective measures in MMS’ most recent marine seismic-survey exploration permits; (3) Open Water 

meetings in 1999 and 2001; and (4) the MMS’ Biological Evaluation for ESA Section 7 consultation with 

NMFS on Arctic Region OCS activities dated March 3, 2006 (USDOI, MMS, 2006). 

Exclusion Zone –A 180/190-dB isopleth-exclusion zone (also called a safety zone) from the seismicsurvey-sound source shall be free of marine mammals before the survey can begin and must remain free of 

mammals during the survey. The purpose of the exclusion zone is to protect marine mammals from Level 

A harassment (injury/harm). The 180-dB (Level A harassment-injury) applies to cetaceans and the Pacific 

walrus, and the 190-dB (Level A harassment-injury) applies to pinnipeds other than the Pacific walrus. 

Monitoring of the Exclusion Zone – Individuals (marine mammal biologists or trained observers) shall 

monitor the area around the survey for the presence of marine mammals to maintain a marine mammal-free 

exclusion zone and monitor for avoidance or take behaviors. Visual observers monitor the exclusion zone 

to ensure that marine mammals do not enter the exclusion zone for at least 30 minutes prior to ramp up, 

during the conduct of the survey, or before resuming seismic-survey work after shut down. The NMFS will 

set specific requirements for the monitoring programs and observers. 

Shut Down – The survey shall be suspended until the exclusion zone is free of marine mammals. All 

observers shall have the authority to, and will, instruct the vessel operators to immediately stop or deenergize the airgun array whenever a marine mammal is seen within the exclusion zone. If the airgun array 

is completely powered down for any reason during nighttime or poor sighting conditions, it shall not be reenergized until daylight or whenever sighting conditions allow for the exclusion zone to be effectively 

monitored from the source vessel and/or through other passive acoustic, aerial, or vessel-based monitoring. 

Ramp Up – Ramp up is the gradual introduction of sound to deter marine mammals from potentially 

damaging sound intensities and from approaching the exclusion zone. This technique involves the gradual 

increase (usually 5-6 dB per 5-minute increment) in emitted sound levels, beginning with firing a single 

airgun and gradually adding airguns over a period of at least 20-40 minutes, until the desired operating 

level of the full array is obtained. Ramp-up procedures may begin after observers ensure the absence of 

marine mammals for at least 30 minutes. Ramp-up procedures shall not be initiated at night or when 

monitoring the exclusion zone is not possible. A single airgun operating at a minimum source level can be 

maintained for routine activities, such as making a turn between line transects, for maintenance needs or 

during periods of impaired visibility (e.g., darkness, fog, high sea states), and does not require a 30-minute 

clearance of the exclusion zone before the airgun array is again ramped up to full output. 

Field Verification – Before conducting the survey, the operator shall verify the radii of the exclusion zones 

within real-time conditions in the field. This provides for more accurate exclusion-zone radii rather than 

 PEA-230 
relying on modeling techniques before entering the field. Field-verification techniques must be consistent 

with NMFS-approved guidelines and procedures. When moving a seismic-survey operation into a new 

area, the operator shall verify the new radii of the exclusion zones by applying a sound-propagation series. 

Monitoring of the Seismic-Survey Area – Aerial-monitoring surveys or an equivalent monitoring 

program acceptable to the NMFS may be required. 

Reporting Requirements – Reporting requirements, such as the monitoring plans required by FWS for 

polar bears and walruses prior to the start of seismic activities, provide the regulating agencies with specific 

information on the monitoring techniques to be implemented and how any observed impacts to marine 

mammals will be recorded. In addition, operators must report immediately any shut downs due to a marine 

mammal entering the exclusion zones and provide the regulating agencies with information on the 

frequency of occurrence and the types and behaviors of marine mammals (if possible to ascertain) entering 

the exclusion zones. 

Temporal/Spatial/Operational Restrictions – Dynamic management approaches to avoid or minimize 

exposure, such as temporal or spatial limitations are based on marine mammals being present in a particular 

place or time, or being engaged in a particularly sensitive behavior (such as feeding). 

• Seismic survey must not occur in the Chukchi Sea spring lead system before July 1, unless 

authorized by NMFS, to provide bowhead cow/calf pairs additional protection. 

• Seismic-survey activities are not permitted within the Ledyard Bay spectacled eider critical-habitat 

area. 

• Seismic-survey support aircraft must avoid overflights of Ledyard Bay critical-habitat area after 

July 1; unless aircraft are at an altitude in excess of 1,500 feet or human safety requires deviation 

(e.g., a medical emergency). 

IV.B. Additional Mitigation Measures to be Considered in the 

Alternatives. 

Given the lack of scientific certainty in some resource areas, MMS adopted a cautious approach in 

assessing potential impacts to certain marine mammal species and other marine biological resources. The 

following mitigation and monitoring measures were identified through the analyses to further reduce the 

potential for adverse environmental impacts and, depending on the scope of seismic-survey activities, could 

be adopted as requirements for seismic-survey-related G&G permits. Additional mitigation measures also 

may be required for MMS permitted seismic surveys by the required MMPA authorizations from NMFS 

and FWS. 

1. Aerial surveys shall be flown in advance of initiating seismic surveys and related icebreaking activities 

over an area that includes the area of interest in the seismic survey plus a buffer area determined by NMFS. 

These aerial surveys shall be flown using a NMFS-approved survey design sufficient to be able to have a 

level of confidence that no more than 12 cow/calf pairs and aggregations of bowhead whales are in the 

surveyed area. These surveys shall continue to be flown throughout the period of the seismic survey, as 

weather conditions allow. 

2. Aerial survey information, especially information about bowhead whale cow/calf pairs or aggregations 

of bowhead whales, shall be provided to NMFS within 24 hours of the aerial survey and will form the basis 

for NMFS determining which additional mitigation measures, if any, will be required over a given time 

period. 

3. If an aggregation of bowhead whales, a large number of scattered bowheads, and/or cow/calf pairs are 

observed within the area to be seismically surveyed, no seismic surveying shall occur nearer than the 120-

dB radius of where the whales were observed, until two consecutive surveys indicate the aggregation is no 

longer present within the 120-dB zone of the seismic-surveying operations. If an aggregation of four or 

more cow/calf pairs is observed at the surface, no seismic surveying shall occur nearer than the 120-dB 

 PEA-231 
radius of where they were observed, until two consecutive surveys indicate they are no longer within the 

120-dB zone of the seismic-surveying operations. 

4. Seismic-survey operators shall notify MMS, NMFS, and FWS in the event of any loss of cable, 

streamer, or other equipment that could pose a danger to marine mammals. 

5. Permit applications shall use the lowest sound levels feasible to accomplish their data-collection needs. 

6. To avoid significant additive and synergistic effects from simultaneous seismic-survey operations that 

might hinder the migration of the bowhead whales, NMFS and MMS will review the seismic-survey plans 

and may require special restrictions, such as temporal or additional spatial separations. 

7. If, during the previously described bowhead whale-aerial surveys, concentrations of feeding gray whales 

are observed within or in proximity to the areas to be seismically surveyed, a 160-dB shut-down/exclusion 

zone for gray whales shall be established. 

8. To create and maintain a movement corridor for fish resources to pass through and avoid airgun 

emissions from multiple seismic-survey operations, seismic surveys shall be planned and conducted such 

that the fish-displacement zone, as calculated using the 160-dB isopleth, does not approach within 15 km 

(9.32 mi) of a fish-displacement zone of another seismic survey being conducted in State or Federal waters 

of the Chukchi and Beaufort seas. Field verification of the fish-displacement zone shall follow the 

procedures identified in Section IV.A.2 (Measures to Mitigate Seismic Exposure to Marine Mammals). 

9. Permittees conducting any seismic surveys in Federal waters shall not allow the fish-displacement zone, 

as determined by the appropriate 160-dB isopleth, to come within 1 km (0.62 mi) of a coastal or insular 

shore. 

10. Seismic cables and airgun arrays shall not be towed in the vicinity of fragile biocenoses. 

• Based on the information provided by MMS on the known location of fragile biocenoses in the 

Chukchi and Beaufort seas, the applicant shall clearly explain to what distance their operations 

will avoid fragile biocenoses. 

• Permittees shall report to MMS if damage to fragile biocenoses occurs as a result of their 

operations. Additionally, Permittees shall notify MMS if they detect any fragile biocenoses 

otherwise not documented in their permit application. 

11. Vessels shall not anchor in the vicinity of any documented fragile biocenoses (e.g., the Boulder Patch, 

natural gardens of coral/sponge or macroalgae [e.g., kelp beds]), unless an emergency situation involving 

human safety specifically exists and there are no other feasible sites in which to anchor at the time. 

12. Seismic-survey vessels are not permitted within the Ledyard Bay critical-habitat area (Figure III.F-2). 

13. Seismic-survey support aircraft would avoid overflights of the Ledyard Bay critical-habitat area 

(Figure III.F-2) after July 1, unless aircraft were at an altitude in excess of 1,500 ft (~450 m) or human 

safety requires deviation (e.g., a medical emergency). 

14. Seismic-survey and support vessels would minimize operations that require high-intensity work lights, 

especially within the 20-m bathymetric contour. 

15. High-intensity lights should be turned off in inclement weather when the seismic vessel is not actively 

conducting surveys; however, navigation lights, deck lights, and interior lights could remain on for safety. 

16. Conflict avoidance-type agreements between seismic-survey operators and the Alaska Eskimo Whaling 

Commission (concerning bowhead whale harvests), the Alaska Beluga Whale Committee (concerning 

beluga whale harvests), the Alaska Eskimo Walrus Commission (concerning walrus harvests), or the Nanuk 

Commission (concerning polar bear harvest) are encouraged. Conflict avoidance-type agreements are used 

 PEA-232 
traditionally as an effective method for mitigating conflicts with subsistence uses and normally specify: (1) 

specific timing and location of Permittee and whaling vessels in operation during the fall/open-water 

season; (2) procedures for communication and providing equipment for communication between Permittees 

and subsistence hunters; (3) providing onboard Inupiat Communicators or seismic-survey operating vessels 

as marine mammal monitors; (4) avoidance guidelines and other mitigation measures the Permittee will 

follow when working in or transiting areas of active or potential whale hunting; (5) measures to be taken in 

the event of a whaling-vessel emergency; (6) provisions for the Permittees’ noise-impact monitoring plan 

(generally agreed on at the annual Open Water Meeting); and (7) a dispute-resolution process. 

17. Seismic and associated support vessels shall observe a 0.5 mi (805 m) safety radius around walrus 

groups hauled out onto land or ice. 

18. Seismic operations shall be shut down if walruses are sighted within the 180-dB (Level A harassmentharm) acoustical safety/exclusion zone. 

19. Aircraft shall be required to maintain a 1,000 ft (305 m) minimum altitude within 0.5 mi (805 m) of 

hauled-out walruses. 

20. Seismic-survey support aircraft would maintain at least a 1,500 ft (305 m) altitude over beaches, 

lagoons, and nearshore waters as much as possible. 

21. The NMFS-approved observers are to record responses of marine birds and waterfowl to seismicsurvey operations. Important aspects to record are reaction distances; molting status of the observed 

bird(s); and difference in reactions between species and flock sizes, as well as weather conditions. It also 

should be noted whether birds moved out of the area or returned to a particular area once the vessel passed 

by. 

22. All bird-vessel collisions would be documented. Minimum information will include species, date/time, 

location, weather, and operational status of the survey vessel when the strike occurred. If eiders or 

murrelets that are injured or killed through collisions are recoverable, survey personnel would contact the 

Fairbanks Fish and Wildlife Field Office, Endangered Species Branch, Fairbanks, Alaska, at 907-456-0499 

for instructions on the handling and disposal of the injured or dead bird. 

23. Seismic-survey operators shall adhere to any mitigation measures identified by the FWS to protect 

polar bears from seismic-survey activities. 

 PEA-233 
V. SELECTED ALTERNATIVE AND MITIGATION 

MEASURES 

V.A Description of the Selected Alternative. 

Alternative 6 (Seismic Surveys for Geophysical-Exploration Activities would be Permitted with Existing 

Alaska OCS Geological and Geophysical Exploration Stipulations and Guidelines and Additional 

Protective Measures for Marine Mammals Including a 180/190 dB-Specified Exclusion Zone) is MMS’ 

selected alternative, and was chosen based on MMS’ examination in the draft Programmatic Environmental 

Assessment (PEA) of the potential impacts associated with the proposed action and the review of 

comments received from the public and agencies. Alternative 6 and the mitigation measures described 

below in Section V.B fulfill MMS’ statutory mission and responsibilities and the stated purpose and need 

for the proposed action (to issue seismic-survey-related geophysical exploration permits that are technically 

safe and environmentally sound) while considering environmental, technical, and economic factors. 

In conducting the analysis, MMS took a broadminded and cautious approach in assessing potential impacts 

and risks to various resources, particularly where there is scientific uncertainty. The MMS also took a 

cautious approach in designing mitigation measures to ensure that potentially adverse impacts would not 

exceed levels of significance and that any remaining residual adverse impacts would be further mitigated to 

the extent practicable. 

V.B Description of Mitigation Measures 

Alternative 6’s mitigation measures will appear as stipulations and guidelines in all 2006 Alaska OCS 

geological and geophysical (G&G) exploration permits for open-water seismic survey activities. 

To ensure compliance with the MMPA, MMS also is requiring seismic-survey operators to obtain from 

NMFS and FWS, an Incidental Take Authorization (ITA), which could be in the form of an Incidental 

Harassment Authorization (IHA) or Letter of Authority (LOA), before commencing MMS-permitted 

seismic-survey activities. The ITA’s mitigation and monitoring requirements would further ensure that 

potential impacts to marine mammals will be negligible and that there will be no unmitigable impacts to 

subsistence uses. The MMPA requires that authorized activities have no unmitigable adverse impact on 

subsistence uses of marine mammals. 

To achieve this standard, the seismic operators are negotiating a Conflict Avoidance Agreement (CAA) 

with the Alaska Eskimo Whaling Commission (AEWC) and the affected villages’ Whaling Captains 

Association. The CAA likely will include a prohibition on conducting seismic surveys during the bowhead 

whale-hunting season in the Beaufort Sea, describe a dispute-resolution process, and provide emergency 

assistance to whalers at sea. Implementation of the CAA further ensures that there will not be significant 

social or economic impacts on the coastal inhabitants of the Beaufort and Chukchi seas by avoiding an 

adverse impact on subsistence marine mammal-harvest activities. 

In order to meet the statutory requirements for MMPA authorization, NMFS and/or FWS must conclude 

that the takings would be of small numbers, have no more than a “negligible impact” on affected marine 

mammal species, and not have an “unmitigable adverse impact” on subsistence harvests of these species. 

These statutory conditions further require that any takings are below the level where injury might occur, the 

anticipated numbers of marine mammals that might be harassed are all relative to the affected species or 

stocks sizes, the cumulative effect of individual takings will not rise to population level impacts, and 

adverse impacts on subsistence-harvest activities will be avoided. To meet these requirements, NMFS and 

FWS will ultimately make determinations through the MMPA authorization process. Exact requirements 

will be set in the ITA’s. All mitigation and monitoring measures contained under these agreements and 

those related to avoiding impacts to subsistence hunting under the MMPA authorizations will be followed 

or the MMS permit/authorization will be suspended until such time that the protective measures can be 

successfully performed and demonstrated. 

 PEA-234 
The following describes the environmental protection measures that shall apply in order to prevent 

significant adverse impacts from occurring during the 2006 seismic survey season in the Chukchi and 

Beaufort seas, and are based on: (1) standard MMS G&G permit stipulations (Appendix A); (2) a 

180dB/190 dB exclusion zone for marine mammals; (3) NMFS’ biological opinion that the activities 

associated with seismic surveys in the Beaufort and Chukchi seas may adversely affect but not jeopardize 

the continued existence of any species listed under the ESA that is under the jurisdiction of NMFS; (4) 

FWS concurring through informal ESA consultation that there will be no adverse impacts on threatened, 

endangered, or candidate species under their jurisdiction; (5) MMPA coordination with NMFS and FWS; 

and (6) the need to protect the marine resources using the spring lead system and Ledyard Bay. 

Alaska OCS Region standard seismic survey permit stipulations (Appendix A)

• No solid or liquid explosives shall be used without specific approval. 

• Operations shall be conducted in a manner to assure that they will not cause pollution, cause 

undue harm to aquatic life, create hazardous or unsafe conditions, or unreasonably interfere with 

other uses of the area. Any difficulty encountered with other users of the area or any conditions 

which cause undue harm to aquatic life, pollution, or could create a hazardous or unsafe condition 

as a result of the operations under this permit shall be reported to the Supervisor. Serious or 

emergency conditions shall be reported without delay. 

• Operators must maintain a minimum spacing of 15 miles between the seismic source vessels for 

separate surveys. The MMS must be notified by means of the weekly report whenever shut down 

of operations occurs to maintain this minimum spacing. 

• Permit applicants shall use the lowest sound levels feasible to accomplish their data-collection 

needs. 

• Vessels and aircraft should avoid concentrations or groups of whales. Operators should, at all 

times, conduct their activities at a maximum distance from such concentrations of whales. Under 

no circumstances, other than an emergency, should aircraft be operated at an altitude lower than 

1,000 feet when within 500 lateral yards of groups of whales. Helicopters may not hover or circle 

above such areas or within 500 lateral yards of such areas. 

• When weather conditions do not allow a 1,000-foot flying altitude, such as during severe storms or 

when cloud cover is low, aircraft may be operated below the 1,000-foot altitude stipulated above. 

However, when aircraft are operated at altitudes below 1,000 feet because of weather conditions, 

the operator must avoid known whale concentration areas and should take precautions to avoid 

flying directly over or within 500 yards of groups of whales. 

• When a vessel is operated near a concentration of whales, the operator must take every precaution 

to avoid harassment of these animals. Therefore, vessels should reduce speed when within 300 

yards of whales and those vessels capable of steering around such groups should do so. Vessels 

may not be operated in such a way as to separate members of a group of whales from other 

members of the group. 

• Vessel operators should avoid multiple changes in direction and speed when within 300 yards of 

whales. In addition, operators should check the waters immediately adjacent to a vessel to ensure 

that no whales will be injured when the vessel’s propellers (or screws) are engaged. 

• Small boats should not be operated at such a speed as to make collisions with whales likely. 

When weather conditions require, such as when visibility drops, vessels should adjust speed 

accordingly to avoid the likelihood of injury to whales. 

• When any Permittee becomes aware of the potentially harassing effects of operations on 

endangered whales, or when any Permittee is unsure of the best course of action to avoid 

harassment of endangered whales (other than those effects authorized by NMFS under the MMPA 

and ESA), every measure to avoid further harassment should be taken until NMFS is consulted for 

instructions or directions. However, human safety will take precedence at all times over the 

guidelines and distances recommended herein for the avoidance of disturbance and harassment of 

endangered whales. 

 PEA-235 
Measures related to the Marine Mammal Protection Act and NMFS and FWS incidental take authorizations 

NMFS and FWS will set the specific requirements within their incidental take authorizations for 

implementation of the measures below. 

Exclusion Zone – A 180/190-dB isopleth-exclusion zone (also called a safety zone) from the seismicsurvey-sound source shall be free of marine mammals before the survey can begin and must remain free of 

mammals during the survey. The purpose of the exclusion zone is to protect marine mammals from Level 

A harassment (injury/harm). The 180-dB (Level A harassment-injury) applies to cetaceans and the Pacific 

walrus, and the 190-dB (Level A harassment-injury) applies to pinnipeds other than the Pacific walrus. 

Monitoring of the Exclusion Zone – Individuals (marine mammal biologists or trained observers) shall 

monitor the area around the survey for the presence of marine mammals to maintain a marine mammal-free 

exclusion zone and monitor for avoidance or take behaviors. Visual observers monitor the exclusion zone 

to ensure that marine mammals do not enter the exclusion zone for at least 30 minutes prior to ramp up, 

during the conduct of the survey, or before resuming seismic-survey work after shut down. The NMFS will 

set specific requirements for the monitoring programs and observers. 

Shut Down – The survey shall be suspended until the exclusion zone is free of marine mammals. All 

observers shall have the authority to, and will, instruct the vessel operators to immediately stop or deenergize the airgun array whenever a marine mammal is seen within the exclusion zone. If the airgun array 

is completely powered down for any reason during nighttime or poor sighting conditions, it shall not be reenergized until daylight or whenever sighting conditions allow for the exclusion zone to be effectively 

monitored from the source vessel and/or through other passive acoustic, aerial, or vessel-based monitoring. 

Ramp Up – Ramp up is the gradual introduction of sound to deter marine mammals from potentially 

damaging sound intensities and from approaching the exclusion zone. This technique involves the gradual 

increase (usually 5-6 dB per 5-minute increment) in emitted sound levels, beginning with firing a single 

airgun and gradually adding airguns over a period of at least 20-40 minutes, until the desired operating 

level of the full array is obtained. Ramp-up procedures may begin after observers ensure the absence of 

marine mammals for at least 30 minutes. Ramp-up procedures shall not be initiated at night or when 

monitoring the exclusion zone is not possible. A single airgun operating at a minimum source level can be 

maintained for routine activities, such as making a turn between line transects, for maintenance needs or 

during periods of impaired visibility (e.g., darkness, fog, high sea states), and does not require a 30-minute 

clearance of the exclusion zone before the airgun array is again ramped up to full output. 

Field Verification – Before conducting the survey, the operator shall verify the radii of the exclusion zones 

within real-time conditions in the field. This provides for more accurate exclusion-zone radii rather than 

relying on modeling techniques before entering the field. Field-verification techniques must be consistent 

with NMFS-approved guidelines and procedures. When moving a seismic-survey operation into a new 

area, the operator shall verify the new radii of the exclusion zones by applying a sound-propagation series. 

Monitoring of the Seismic-Survey Area – Aerial-monitoring surveys or an equivalent monitoring 

program acceptable to the NMFS may be required. 

Reporting Requirements – Reporting requirements, such as the monitoring plans required by FWS for 

polar bears and walruses prior to the start of seismic activities, provide the regulating agencies with specific 

information on the monitoring techniques to be implemented and how any observed impacts to marine 

mammals will be recorded. In addition, operators must report immediately any shut downs due to a marine 

mammal entering the exclusion zones and provide the regulating agencies with information on the 

frequency of occurrence and the types and behaviors of marine mammals (if possible to ascertain) entering 

the exclusion zones. 

Temporal/Spatial/Operational Restrictions – Dynamic management approaches to avoid or minimize 

exposure, such as temporal or spatial limitations are based on marine mammals being present in a particular 

place or time, or being engaged in a particularly sensitive behavior (such as feeding). 

 PEA-236 
• Seismic survey must not occur in the Chukchi Sea spring lead system before July 1, unless 

authorized by NMFS, to provide bowhead cow/calf pairs additional protection. 

• Seismic-survey activities are not permitted within the Ledyard Bay spectacled eider critical-habitat 

area. 

• Seismic-survey support aircraft must avoid overflights of Ledyard Bay critical-habitat area after 

July 1; unless aircraft are at an altitude in excess of 1,500 feet or human safety requires deviation 

(e.g., a medical emergency). 

As noted earlier, given the lack of scientific certainty in some areas, MMS adopted a cautious approach in 

assessing potential impacts to certain marine mammal species and other marine biological resources. The 

following mitigation measures will further reduce the potential for causing adverse environmental impacts. 

The specific measures identified in NMFS and FWS ITA’s will apply, where applicable, including 

protocols for monitoring programs. 

• A 120-dB monitoring (safety) zone for bowhead whales in the Beaufort Sea will be established 

and monitored, once four or more bowhead whale cow/calf pairs are observed at the surface 

during an aerial monitoring program within the area to be seismically surveyed during the next 24 

hours. No seismic surveying shall occur within the 120-dB safety zone around the area where the 

whales were observed, until two consecutive surveys (aerial or vessel) indicate they are no longer 

present within the 120-dB safety zone of seismic-surveying operations. 

• A 120-dB aerial monitoring zone for bowhead whales in the Chukchi Sea will be established and 

monitored: (1) once four or more migrating bowhead whale cow/calf pairs are observed at the 

surface during the vessel research-monitoring program; (2) once Barrow whalers notify NMFS or 

MMS that bowhead whale cow/calf pairs are passing Barrow; or (3) on September 25, whichever 

is earliest. Once notified by NMFS or MMS, a daily aerial survey will occur (weather permitting) 

within the area to be seismically surveyed during the next 24 hours. Whenever four or more 

migrating bowhead whale cow/calf pairs are observed at the surface during an aerial monitoring 

program, no seismic surveying shall occur within the 120-dB monitoring zone around the area 

where the whales were observed by aircraft, until two consecutive surveys (aerial or vessel) 

indicate they are no longer present within the 120-dB safety zone of seismic-surveying operations. 

• A 160-dB vessel monitoring zone for bowhead and gray whales will be established and monitored 

in the Chukchi Sea during all seismic surveys. Whenever an aggregation of bowhead whales or 

gray whales (12 or more whales of any age/sex class that appear to be engaged in a nonmigratory, 

significant biological behavior [e.g., feeding, socializing]) are observed during an aerial or vessel 

monitoring program within the 160-dB safety zone around the seismic activity the seismic 

operation will not commence or will shut down immediately, until two consecutive surveys (aerial 

or vessel) indicate they are no longer present within the 160-dB safety zone of seismic-surveying 

operations. 

• Dedicated aerial and/or vessel surveys, if determined by NMFS to be appropriate and necessary, 

shall be conducted in the Beaufort and Chukchi seas during the fall bowhead whale-migration 

period to detect bowhead whale cow/calf pairs and to detect aggregations of feeding bowhead and 

gray whales. The protocols for these aerial and vessel monitoring programs will be specified in 

the MMPA authorizations granted by NMFS. 

• Survey information, especially information about bowhead whale cow/calf pairs or feeding 

bowhead or gray whales, shall be provided to NMFS as required in ITA’s, and will form the basis 

for NMFS determining whether additional mitigation measures, if any, will be required over a 

given time period. 

• Seismic-survey and associated support vessels shall observe a 0.5-mile (~800-meter) safety radius 

around Pacific walrus groups hauled out onto land or ice. 

• Aircraft shall be required to maintain a 1,000-foot minimum altitude within 0.5 miles of hauledout Pacific walruses. 

• Seismic-survey operators shall notify MMS, NMFS, and FWS in the event of any loss of cable, 

streamer, or other equipment that could pose a danger to marine mammals. 

 PEA-237 
• To avoid significant additive and synergistic effects from simultaneous seismic-survey operations 

that might hinder the migration of bowhead whales, NMFS and MMS will review the seismicsurvey plans and may require special restrictions, such as additional temporal or spatial 

separations. 

• Seismic cables and airgun arrays must not be towed in the vicinity of fragile biocenoses, unless 

MMS determines the proposed operations can be conducted without damage to the fragile 

biocenoses. Seismic-survey and support vessels shall not anchor in the vicinity of fragile 

biocenoses (e.g., the Boulder Patch, kelp beds) as identified by MMS or may be discovered by the 

operator during the course of their operations, unless there is an emergency situation involving 

human safety and there are no other feasible sites in which to anchor at the time. Permittees must 

report to MMS any damage to fragile biocenoses as a result of their operations. 

• Seismic-survey and support vessels will minimize operations that require high-intensity work 

lights, especially within the 20-m-bathymetric contour, to minimize the potential for adverse 

impacts to marine birds. 

• High-intensity lights will be turned off in inclement weather when the seismic vessel is not 

actively conducting surveys to minimize the potential for adverse impacts to marine birds; 

however, navigation lights, deck lights, and interior lights could remain on for safety. 

• All bird-vessel collisions shall be documented. Minimum information will include species, 

date/time, location, weather, and operational status of the survey vessel when the strike occurred. 

If eiders or murrelets that are injured or killed through collisions are recoverable, seismic-survey 

personnel should contact the Fairbanks Fish and Wildlife Field Office, Endangered Species 

Branch, Fairbanks, Alaska, at 907-456-0499 for instructions on the handling and disposal of the 

injured or dead bird(s). 

• Seismic-survey operators shall adhere to any mitigation measures identified by the FWS to protect 

polar bears from seismic-survey activities. 

 PEA-238 
VI. CONSULTATION AND COORDINATION 

The MMS solicited public participation and received input regarding potential effects from seismic 

activities throughout preparation of the draft PEA. In late 2005, MMS sent letters to the affected North 

Slope Borough, local and Tribal governments, and the Native whaling, beluga, and walrus commissions 

notifying them of the possibility of seismic surveys in 2006 and soliciting their initial concerns about the 

proposed activities. In early 2006, MMS conducted outreach and scoping in Alaskan communities on a 

range of OCS activities, including for the Draft Proposed Program for 2007-2012 OCS Oil and Gas Leasing 

(5-Year Program), the 5-Year Program EIS, and the proposed Chukchi Sea Lease Sale 193 EIS. During the 

public meetings and Government-to-Government meetings on the North Slope, MMS personnel discussed 

how seismic surveys are conducted and that work was progressing on the PEA to evaluate the effects of 

possible seismic-survey activity in the summer of 2006 in the Beaufort Sea and Chukchi seas. The 

presentations highlighted our desire to received input on the resources, issues, alternatives, and mitigation 

measures to be included in the environmental analysis. We emphasized that any input received in these 

meetings would be considered in all analyses, and that any statements made concerning seismic activities 

would be considered in the PEA. 

In early April 2006, the draft PEA was distributed for 30-day public review and comment. In response to 

requests from stakeholders, the comment period was extended for two days and closed May 10. Also in 

April 2006, NMFS received input on the PEA and proposed IHA’s during the Open Water Meetings. 

The MMS received substantive written comments on the draft PEA from the following: 

Alaska Eskimo Whaling Commission (AEWC) 

Alaska Oil and Gas Association (AOGA) 

American Petroleum Institute (API) 

ConocoPhillips, Alaska, Inc. (ConocoPhillips) 

ExxonMobil 

International Association of Geophysical Contractors (IAGC) 

Natural Resources Defense Council (NRDC) 

North Slope Borough (NSB) 

John W. Richardson 

Shell Exploration and Production (Shell) 

WesternGeco 

In addition, MMS received approximately 500 email form letters. 

All received comments are part of the record of information used in developing the final PEA. The 

majority of comments received by MMS addressed similar sweeping issues (e.g. EIS versus EA, 

significance criteria, potential mitigation measures, reasonable alternatives, data quality, and data gaps). A 

summary of the major categories of comments and our response to those comments can be found in 

Appendix D. After careful consideration and evaluation, many of these substantive comments resulted in 

modifying the text in the PEA. 

The NMFS agreed to become a cooperating agency on the PEA with MMS as lead agency. The MMS and 

NMFS jointly developed the alternatives and mitigation measures, determined the issues to be addressed in 

the PEA, determined the spatial and temporal scope of the cumulative analysis, solicited comments from 

stakeholders on the draft PEA, prepared responses to comments, and prepared the final EA including 

development of the Selected Alternative. 

The FWS declined to become a cooperating agency on the PEA as they were well into the NEPA and 

rulemaking processes for their renewal of the LOA in the Beaufort Sea. 

 PEA-239 
The MMS has completed the various required consultation processes. These consultations support the PEA 

and subsequent environmental review of 2006 G&G permit applications. The consultations are 

summarized below. 

On August 12, 2005, MMS requested from NMFS a list of threatened, endangered, and candidate species 

and critical habitats pursuant to section 7 of the Endangered Species Act. The NMFS responded with a list 

that included the endangered bowhead whale and noted critical habitat has not been designated for 

bowhead whale (dated September 30, 2005). The NMFS also noted that the endangered humpback and fin 

whale are found in the Chukchi and Bering seas outside of the OCS Planning Areas. The MMS provided a 

request for Arctic Regionwide consultation and a biological evaluation (dated March 3, 2006). The MMS 

described the anticipated impacts that OCS activities, including exploration seismic surveys, could have on 

endangered bowhead whales. The MMS also included a discussion of potential impacts to the endangered 

humpback and fin whale. The BE discussed mitigation measures to avoid and minimize impacts to these 

species. On June 16, 2006, NMFS provided their Arctic Region Biological Opinion (ARBO) stating that 

the activities associated with seismic surveys in the Beaufort and Chukchi seas may adversely affect but not 

jeopardize the continued existence of any species listed under the ESA that is under the jurisdiction of 

NMFS. 

On December 13, 2005, MMS requested from FWS a list of threatened, endangered, and candidate species 

and critical habitats pursuant to section 7 of the Endangered Species Act. The FWS responded with a list 

that included the threatened spectacled and Steller’s eiders and the candidate Kittlitz’s murrelet, and the 

critical habitat area from Point Hope eastward to the Canadian border (dated January 5, 2006). The MMS 

provided a request for consultation and a biological evaluation for proposed seismic surveys during 2006 in 

the Chukchi Sea and Beaufort Sea Planning Areas (dated March 13, 2006). The MMS described the 

anticipated impacts the proposed seismic-survey program for 2006 would have on threatened spectacled 

and Steller’s eiders and Kittlitz’s murrelets (a candidate species), including mitigation measures to avoid 

and minimize impacts to coastal and marine birds. Subsequent discussions resulted in the decision by 

MMS to change a mitigation measure to exclude seismic survey activities from the Ledyard Bay critical 

habitat area instead of allowing these activities to occur there prior to July 1 or after October 15. On May 

11, 2006, the FWS, assuming revised mitigation measures are implemented, concurred with MMS’ 

conclusion that no adverse effects are likely to occur to listed or candidate species under their jurisdiction. 

The 1996 reauthorization of the Magnuson-Stevens Conservation and Management Act amendments 

require consultation between the Secretary of Commerce and Federal and State agencies on activities that 

may adversely impact essential fish habitat for those commercial fish species managed by fish management 

plans and managed under the Act. According to the final Essential Fish Habitat Consultation Agreement, 

dated April 4, 2003, between the MMS and NMFS, the MMS incorporates essential fish habitat 

consultation into the NEPA process. Measures recommended by NMFS to protect EFH are advisory, not 

proscriptive. The MMS forwarded the draft PEA and request for EFH consultation to NMFS on April 7, 

2006, and received the response from NMFS on June 6, 2006. The NMFS stated that further EFH 

consultation is not necessary, unless implementation of the plan or operational conditions change. In 

accordance with the MMS/NMFS EFH agreement, MMS will provide a detailed response to NMFS in 

writing within 30 days after receiving the EFH Conservation Recommendations. 

The MMS initiated Section 106 consultation, as required by the National Historic Preservation Act of 1966. 

By letter dated April 24, 2006, MMS asked for concurrence by the State of Alaska Office of History and 

Preservation (AOHP) on our determination that the Proposed Action would have no adverse effect on the 

archaeological resources in the Beaufort and Chukchi seas. The AOHP responded on June 13, 2006, 

stating that they concur with MMS’ finding that no historic properties would be affected by marinestreamer 3D and 2D seismic surveys or high-resolution site surveys. However, because ocean-bottomcable surveys potentially could adversely affect historic properties, they recommend—and MMS will—

conduct additional consultation regarding any applications for ocean-bottom-cable surveys. 

 PEA-240 
VII. LIST OF PREPARERS AND CONTRIBUTORS 

Minerals Management Service – Alaska OCS Region

Elinore M. Anker Technical Publications Writer-Editor 

Susan Banet Supervisory Geologist, Resource Analysis Section 

Michael Burwell Socioeconomic Specialist 

Jeff Childs Wildlife and Fisheries Biologist 

Deborah Cranswick Supervisory Environmental Specialist, Environmental 

Assessment Section 

Wayne M. Crayton Biologist and NEPA Team Coordinator 

Deborah Epperson Wildlife Biologist 

John Goll Regional Director 

Tim Holder Socioeconomic Specialist 

David Johnston Minerals Leasing Specialist 

Ida Menge Cartographer 

Tom Newbury Biological Oceanographer 

Mazelle O. Parker EIS Specialist 

Mark Schroeder Endangered Species and Wildlife Biologist 

Peter Sloan Geologist 

Caryn Smith Oceanographer 

Paul Stang Regional Supervisor, Leasing and the Environment 

Lisa Rotterman Endangered Species and Marine Mammal Biologist 

Jeffrey Walker Regional Supervisor, Field Operations 

Rance Wall Regional Supervisor, Resource Evaluation Branch 

James Wilder Marine Mammal Biologist 

Minerals Management Service – Headquarters

Jill Lewandowski Marine Biologist 

Judy Wilson Chief, Environmental Compliance Unit 

National Oceanic and Atmospheric Admininstration - Fisheries

Matthew Eagleton Fisheries Biologist 

Ken Hollingshead Fishery Biologist 

Brad Smith Protected Resources Biologist 

U.S. Army Corps of Engineers, Alaska District

Larry Bartlett Fish and Wildlife Biologist 

Christopher Hoffman Wildlife Biologist 

Guy McConnell Chief Environmental Resources Section 

 PEA-241 
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