Aerial Surveys of Endangered 

Whales in the Beaufort Sea, 

Fall 2001

OCS Study

MMS 2002-061 

 

 

By Stephen D. Treacy, Research Manager 

MMS Bowhead Whale Aerial Survey 

 

 

 

 

 

 

 

 

 

U.S. Department of the Interior 

Minerals Management Service Anchorage, Alaska 

Alaska OCS Region 2002 
ABSTRACT

This report describes field activities and data analyses for aerial surveys of bowhead whales conducted during 

Fall 2001 (31 August-19 October) in the Beaufort Sea, primarily between 140°W. and 157°W. longitudes south 

of 72°N. latitude. 

During Fall 2001, general ice cover during September and October was the 35th-mildest open-water season 

(1953-2001). Low cloud ceilings, with occasional high sea states, permitted only 23 flights during Fall 2001. 

Military flight restrictions were imposed from 11 through 14 September. There were 29 sightings for a total of 

35 bowhead whales counted during Fall 2001. Additionally, 6 gray whales, 386 beluga whales, 11 bearded 

seals, 42 ringed seals, 6 polar bears, and 43 sets of polar bear tracks were observed during 72.93 hours of 

survey effort that included 38.35 hours on randomized transects. The initial sighting of bowhead whales in 

Alaskan waters occurred on 5 September. Of the 35 bowheads observed, half (median) had been counted by 

7 September. The peak count (mode) of 12 bowheads also occurred on 5 September. The last sighting of 

bowhead whales was made on 2 October. 

In 2001, the axis of bowhead whale sightings in the East Region (33.9 km) and the West Region (42.4 km) 

were within the 25th – 75th quartile ranges for all years (1982-2001). 

Greater relative occurrence of feeding and/or milling behaviors of bowhead whales was observed on transect

in six of the 20 years (1984, 1989, 1997, 1998, 1999 and 2000) near the mouth of Dease Inlet, Alaska. Similar 

relative occurrence of feeding and/or milling behaviors of bowheads was observed on transect in four of those 

years (1989, 1997, 1998 and 1999) near Cape Halkett, Alaska. There were nine years when feeding and/or 

milling behaviors were noted on transect but not near Dease Inlet or Cape Halkett (1982, 1983, 1985, 1986, 

1988, 1990, 1993, 1995, and 1996). In five other years (1987, 1991, 1992, 1994, and 2001), neither feeding 

nor milling behaviors were observed on transect anywhere in the study area. 

i
ACKNOWLEDGMENTS

Project Management

Cleveland J. Cowles, Ph.D., Supervisor 

Stephen D. Treacy, Research Manager 

Minerals Management Service (MMS) Project Field Science

Name Position Flights

Stephen D. Treacy Research Manager/Team Leader Flights 1-12 

Donald Hansen Team Leader Flights 13-23 

Kristopher Nuttall Data Recorder-Observer Flights 1-10 

Charles Monnett, Ph.D. Data Recorder/Observer Flights 11-15 

James Scherr Data Recorder/Observer Flights 16-23 

Thomas C. Warren Primary Observer Flights 1-8 

Charles Monnett, Ph.D. Primary Observer Flights 9-10, 16-19 

Kristopher Nuttall Primary Observer Flights 11 

Geraldine Taylor Primary Observer Flights 12 

Joel Hubbard, Ph.D. Primary Observer Flights 13-14 

James Scherr Primary Observer Flights 15 

Ed Glazier Primary Observer Flights 20-23 

MMS Bowhead Whale Aerial Survey Project (BWASP) Field Support 

Stephen D. Treacy MMS Contracting Officer’s Technical Representative: MMS/Office of Aircraft

Services (OAS) Interagency Agreement 05052 

Tom Murrell Data-Collection System Developer/Consultant 

Kyle Monkelien Field Equipment Coordinator 

Linda Reeves Field Support Coordinator 

Report Production

Matt Heller Mapping/Data Management Consultant, Resource Data (ArcView 3.2a) 

Elinore Anker Manuscript submission to printer 

National Marine Fisheries Service (NMFS) Liaison

Brad Smith, NMFS, Anchorage, Alaska 

We acknowledge the U.S. Department of the Interior (USDOI), OAS, for making all aircraft arrangements and 

for monitoring satellite tracking of survey flights; Romie Carpenter, Steve Cooper, Robert Kipp, and Tom 

Warner (ERA Aviation) for piloting the Twin Otter in 2001. 

We appreciate review comments on this and/or previous project reports by NMFS, State of Alaska, North 

Slope Borough (NSB), Indigenous People's Council for Marine Mammals, and National Ice Center. 

The project acknowledges the National Ice Center for draft sea-ice-severity rankings and for sea-ice 

concentrations in ARC/INFO format (www.natice.noaa.gov). Ann Treacy contributed the cover illustration. 

iii
CONTENTS 

Page 

ABSTRACT.................................................................................................................................................... i 

ACKNOWLEDGMENTS .............................................................................................................................. iii 

I. INTRODUCTION....................................................................................................................................... 1 

II. METHODS AND MATERIALS................................................................................................................. 3 

A. Study Area................................................................................................................................. 3 

B. Equipment ................................................................................................................................. 3 

C. Aerial-Survey Design................................................................................................................ 5 

D. Survey-Flight Procedures........................................................................................................ 6 

E. Data Entry.................................................................................................................................. 6 

F. General Data Analyses ............................................................................................................. 6 

G. Analysis of the Bowhead Whale Migration Corridor............................................................. 8 

H. Sighting-Rate and Relative-Occurrence Maps....................................................................... 9 

I. Oceanographic Regions........................................................................................................... 9 

III. FALL 2001 RESULTS .......................................................................................................................... 13 

A. Environmental Conditions..................................................................................................... 13 

B. Survey Effort ........................................................................................................................... 13 

C. Bowhead Whale (Balaena mysticetus) Observations ......................................................... 13 

 1. Sighting Summary...................................................................................................... 13 

 2. Sighting Rates ............................................................................................................ 23 

3. Migration Timing ........................................................................................................ 23 

4. Habitat Associations.................................................................................................. 23 

 5. Behaviors.................................................................................................................... 27 

6. Distance from Shore .................................................................................................. 27 

D. Other Marine Mammal Observations .................................................................................... 27 

1. Gray Whale (Eschrichtius robustus) ........................................................................ 27 

2. Beluga Whale (Delphinapterus leucas).................................................................... 27 

3. Bearded Seal (Erignathus barbatus nauticus) ........................................................ 27 

4. Ringed Seal (Pusa hispida hispida).......................................................................... 27 

5. Walrus (Odobenus rosmarus divergens)................................................................. 27 

 6. Unidentified Cetaceans and Pinnipeds.................................................................... 27 

7. Polar Bear (Ursus maritimus marinus) .................................................................... 27 

IV. INTERANNUAL RESULTS.................................................................................................................. 35 

A. Statistical Analyses of Bowhead Whale Sighting Distribution (1982-2001)...................... 35 

1. Central Tendency Statistics - Distance from Shore................................................ 35 

2. Central Tendency Statistics - Water Depth.............................................................. 35 

3. ANOVA – Distance from Shore ................................................................................. 35 

4. Tukey HSD Test - Distance from Shore.................................................................... 35 

B. General Sea Ice Severity (1979-2001) ................................................................................... 40 

C. Fall Spatial Variation in Bowhead Whale Feeding and Milling Activity (1982-2001) ........ 40 

D. Key Results Summary............................................................................................................ 42 

V. DISCUSSION......................................................................................................................................... 45 

A. Management Use of Real-Time Field Information ............................................................... 45 

B. Management Use of Interannual Monitoring........................................................................ 45 

C. Conclusions ............................................................................................................................ 46 

D. Field Coordination and Other Information Support ............................................................ 47 

iii
VI. LITERATURE CITED ........................................................................................................................... 49 

APPENDICES 

Appendix A: Fall-2001 Ice-Concentration Maps for the Alaskan Beaufort Sea...................... 53 

Appendix B: Fall-2001 Bowhead Whale Sighting Data............................................................. 65 

Appendix C: Fall-2001 Daily Flight Summaries......................................................................... 69 

Appendix D: Fall Feeding and Milling Whales per Unit Effort (1982-2000)............................. 95 

Appendix E: Glossary of Abbreviations, Acronyms, and Initialisms .................................... 115 

iv
LIST OF FIGURES

Figure 

Number Title Page

1 Study Area Showing Survey Blocks.............................................................................................. 4 

2 East and West Regions and Selected Isobaths.......................................................................... 10 

3 Combined Flight Tracks, 1-15 September 2001 ......................................................................... 16 

4 Combined Flight Tracks, 16-30 September 2001 ....................................................................... 17 

5 Combined Flight Tracks, 1-15 October 2001 .............................................................................. 18 

6 Combined Flight Tracks, 16-19 October 2001 ............................................................................ 19 

7 Map of Bowhead Whale Sightings, 1-15 September 2001 ......................................................... 20 

8 Map of Bowhead Whale Sightings, 1-15 October 2001 .............................................................. 21 

9 Map of Bowhead Whale Sightings, Fall 2001 ............................................................................. 22 

10 Sighting Rates of Bowhead Whales on Transect, Fall 2001....................................................... 26 

11 Bowhead Whale Sightings on Transect during Fall 2001, Showing Mean Distance 

from a Normalized Shoreline ...................................................................................................... 28 

12 Map of Gray Whale Sightings, Fall 2001 .................................................................................... 29 

13 Map of Beluga Whale Sightings, Fall 2001 ................................................................................. 30

14 Map of Bearded Seal Sightings, Fall 2001.................................................................................. 31 

15 Map of Ringed Seal Sightings, Fall 2001.................................................................................... 32 

16 Map of Polar Bear Sightings, Fall 2001 ...................................................................................... 33 

17 Map of Polar Bear Tracks, Fall 2001 .......................................................................................... 34 

18 Fall-2000 Counts of Feeding and Milling Bowhead Whales per Unit Effort – on Transect ......... 41 

v
LIST OF TABLES

Table 

Number Title Page

1 Operational Definitions of Observed Whale Behaviors................................................................. 7 

2 Aerial-Survey Effort in the Beaufort Sea, 31 August-19 October 2001, 

by Survey Flight .......................................................................................................................... 14 

3 Summary of Marine Mammal Sightings, 31 August-19 October 2001, 

by Survey Flight .......................................................................................................................... 15 

4 Number of Sightings and Total Bowhead Whales Observed per Hour, 

31 August-19 October 2001, by Flight Day................................................................................. 24 

5 Semimonthly Summary of Bowhead Whales Observed, by Percent Ice Cover 

Present at Sighting Location, Fall 2001 ...................................................................................... 25 

6 Semimonthly Summary of Bowhead Whales Observed, by Behavioral Category, 

 Fall 2001 ..................................................................................................................................... 25 

7 Central-Tendency Statistics for Distance from Shore to Random Sightings of Bowhead 

Whales (September-October), by Year and Region, 1982-2001 ................................................ 36 

8 Central-Tendency Statistics for Water Depth at Random Sightings of Bowhead 

Whales (September-October), by Year and Region, 1982-2001 ................................................ 38 

vi
I. INTRODUCTION

In 1953, the Outer Continental Shelf Lands Act (OCSLA) (43 USC 1331-1356) charged the Secretary of the 

Interior with the responsibility for administering minerals exploration and development of the OCS. The Act 

empowered the Secretary to formulate regulations so that its provisions might be met. The OCSLA 

Amendments of 1978 (43 USC 1802) established a policy for the management of oil and natural gas in the 

OCS and for protection of the marine and coastal environments. The amended OCSLA states that the 

Secretary of the Interior shall conduct studies in areas or regions of sales to ascertain the “environmental 

impacts on the marine and coastal environments of the outer Continental Shelf and the coastal areas which 

may be affected by oil and gas development” (43 USC 1346). 

Subsequent to the passage of the OCSLA, the Secretary of the Interior designated the Bureau of Land 

Management (BLM) as the administrative agency responsible for leasing submerged Federal lands and the 

Conservation Division of the U.S. Geological Survey for classification and evaluation of submerged Federal 

lands and regulation of exploration and production. In 1982, the Minerals Management Service (MMS) 

assumed these responsibilities. 

To provide information used in environmental impact statements and environmental assessments under the 

National Environmental Policy Act of 1969 (42 USC 4321-4347), and to assure protection of marine mammals 

under the Marine Mammal Protection Act of 1972 (16 USC 1361-1407) and the Endangered Species Act 

(ESA) of 1973 (16 USC 1531-1543), BLM funded numerous studies involving acquisition and analysis of 

marine mammal and other environmental data. 

In June 1978, BLM entered into an ESA Section 7 consultation with NMFS. The purpose of the consultation 

was to determine the likely effects of the proposed Beaufort Sea Oil and Gas Lease Sale on endangered 

bowhead (Balaena mysticetus) and gray (Eschrichtius robustus) whales. The NMFS determined that 

insufficient information existed to conclude whether the proposed Beaufort Sea sale was or was not likely to 

jeopardize the continued existence of bowhead and gray whales. In August 1978, NMFS recommended 

studies to BLM that would fill the information needs identified during the Section 7 consultation. Subsequent 

biological opinions for leasing and exploration in the Beaufort Sea (Sales 71, 87, and 97) and the 1988 Arctic 

Region Biological Opinion (ARBO), used for Beaufort and Chukchi Sea sales (Sales 124, 126, 144, and 170), 

recommended continuing studies of whale distribution and OCS-industry effects on bowhead whales (USDOC, 

NOAA, NMFS, 1982, 1983, 1987, 1988) and monitoring of bowhead whale presence during periods when 

geophysical exploration and drilling are occurring. The current ARBO, issued by NMFS in 2001 for leasing 

and exploration in the Beaufort Sea, also recommends that whale distribution studies during the fall migration

continue, along with acoustic monitoring studies to describe the impact of exploration activities on the 

migration path of bowhead whales in the Beaufort Sea. 

Following several years when drilling was limited to the period 1 November through 31 March (USDOI, MMS, 

1979), a variable 2-month seasonal-drilling restriction on fall exploratory activity in the joint Federal/State 

Beaufort Sea sale area was implemented. The period of restriction would vary depending on bowhead whale 

presence, and “this determination would require development of a monitoring program. . ..” (USDOI, MMS, 

1982). Subsequently, MMS (Alaska OCS Region) adopted an endangered whale-monitoring plan that 

required aerial surveys. The Diapir Field Sale 87 Notice of Sale (NOS) (1984) states that “Bowhead whales 

will be monitored by the Government, the lessee, or both to determine their locations relative to operational 

sites as they migrate through or adjacent to the sale area” (USDOI, MMS, 1984). Subsequent lease sales in 

the Beaufort Sea (Sales 97, 124, 144, and 170) did not include a seasonal drilling restriction but the NOS for 

each contained an Information to Lessees clause that “MMS intends to continue its areawide endangered 

whale monitoring program in the Beaufort Sea during exploration activities” (USDOI, MMS, 1988, 1991, 1996, 

1998). Information gathered is used to help determine the extent, if any, of adverse effects on the species. 

From 1979 to 1987, the MMS (formerly BLM) funded annual monitoring of endangered whales in arctic waters 

under Interagency Agreements with the Naval Ocean Systems Center and through subcontracts to SEACO, 

Inc. On 15 April 1987, a proposal for MMS scientists to conduct aerial surveys of endangered whales was 

approved by the Associate Director for Offshore Minerals Management. The MMS uses agency personnel to

perform fieldwork and reporting activities for the Beaufort Sea on an annual basis. Previous survey reports are 

1
available for inspection at the Minerals Management Service, Alaska OCS Region, Resource Center, 949 East 

36th Avenue, Anchorage, Alaska 99508-4363. 

The goals of the ongoing program for monitoring endangered whales are to: 

1. Define the annual fall migration of bowhead whales, significant inter-year differences, and long-term trends 

in the distance from shore and water depth at which whales migrate; 

2. Monitor temporal and spatial trends in the distribution, relative abundance, habitat, and behaviors 

(especially feeding) of endangered whales in arctic waters; 

3. Provide real-time data to MMS and NMFS on the general progress of the fall migration of bowhead whales 

across the Alaskan Beaufort Sea, for use in protection of this Endangered Species; 

4. Provide an objective wide-area context for management interpretation of the overall fall migration of 

bowhead whales and site-specific study results; 

5. Record and map beluga whale distribution and incidental sightings of other marine mammals; and 

6. Determine seasonal distribution of endangered whales in other planning areas of interest to MMS. 

2
II. METHODS AND MATERIALS

A. Study Area

The annual survey program has been based on a design of random field transects within established 

geographic blocks overlapping or near Chukchi and Beaufort Sea sale areas offshore of Alaska. The present

study, which was focused on the fall bowhead whale migrations during 2001, included Beaufort Sea Survey 

Blocks 1 through 12 (Fig. 1) between 140°W. and 157°W. longitude south of 72°N. latitude. 

A large-scale Beaufort Gyre moves waters clockwise from the Canadian Basin westward in the deeper 

offshore regions. Nearshore surface currents tend to follow local wind patterns and bathymetry, moving from 

the east in winter, with an onshore component, and to the west in summer, with an offshore component 

(Brower et al., 1988). There is recent evidence for the existence of two regimes or climate states for arctic 

atmospheric-ice-ocean circulation. Based on analysis of modeled sea level and ice motion, wind-driven 

motion in the Arctic was found to alternate between anticyclonic and cyclonic circulation, with each regime 

persisting for 5-7 years (Proshutinsky and Johnson, 1997; Johnson et al., 1999). 

In the Beaufort Sea, landfast ice forms during the fall and may eventually extend up to 50 kilometers (km) 

offshore by the end of winter (Norton and Weller, 1984). The pack ice, which includes multiyear ice averaging 

4 meters (m) in thickness, with pressure ridges up to 50 m thick (Norton and Weller, 1984), becomes 

contiguous with the new and fast ice in late fall—effectively closing off the migration corridor to westbound 

bowhead whales. From early November to mid-May, the Beaufort Sea normally remains almost totally 

covered by ice considered too thick for whales to penetrate. In mid-May, a recurring flaw lead can form just 

seaward of the stable fast ice, followed by decreasing ice concentrations (LaBelle et al., 1983) and large areas 

of open water in summer. 

Local weather patterns affect the frequency and effectiveness of all marine aerial surveys. The present study

area is in the arctic climate zone, with mean temperatures at the Alaskan Beaufort Sea coast communities of 

Barrow, Lonely, Oliktok, and Barter Island from -0.9°C to -0.1°C during September and from -9.7°C to -8.5°C 

during October. Precipitation in these communities occurred an average of 10 to 34 percent of the time during 

September (snow with some rain) and 13 to 43 percent during October (almost all snow), with the heaviest 

precipitation at Barrow and Barter Island during both months. Fog (without precipitation) reduces visibility

approximately 11 to 19 percent of the time during September and 6 to 8 percent of the time during October. 

Mean windspeed in the same communities is from 5 to 6 m per second during September and 5 to 7 m per 

second during October (Brower et al., 1988). 

Sea state is another environmental factor affecting visibility during aerial surveys. Surface waters in the 

Beaufort Sea are driven primarily by wind. Ocean waves are generally from northerly or easterly directions 

during September and October, during which time the ice pack continues to limit fetch. Because of the pack 

ice, significant wave heights are reduced by a factor of 4 from heights that would otherwise be expected during 

the open-water season. Wave heights greater than 0.5 m occurred in 23.9 to 38.9 percent of observations 

during September and 14.1 to 37.4 percent during October, with the greater percentage of larger waves (>0.5 

m) reported for the eastern third of the study area during both months. Wave heights greater than 3.5 m are 

not reported within the study area during September or October (Brower, 1988). 

The study area contains sufficient zooplankton to support some feeding by bowhead whales. The availability

of zooplankton during the fall would be expected to vary between years, geographic locations, and water 

depths in response to ambient oceanographic conditions. In September 1985 and 1986, average zooplankton 

biomass in the Alaskan Beaufort Sea east of 144°W. longitude was highest south of the 50-m isobath in 

subsurface water (LGL Ecological Research Associates, Inc., 1987). 

B. Equipment

The survey aircraft was a de Havilland Twin Otter Series 300 (call sign: N321EA). The aircraft was equipped 

with two medium-size bubble windows behind the cabin bulkhead and one on the aft starboard side that 

afforded complete trackline viewing. The pilot and copilot seats provided good forward and side viewing. 

3
                   

                  



  

 



















	

























	





		

		

	

	





	





		

		

	

	



	
















	




	 

 







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Each observer was issued a hand-held clinometer (Suunto) for measuring the angle of inclination to the 

sighting location of endangered whales. Observers and pilots were linked to common communication 

systems, and commentary could be recorded. The aircraft's maximum time aloft under normal survey load 

was extended to approximately 8 hours (hr) through the use of a supplemental onboard fuel tank. 

A portable Gateway Solo 5100 SE laptop computing system was used aboard the aircraft to store and analyze 

flight and observational data. From 30 August through 15 September, the computer system was connected to 

a local Garmin III Global Positioning System (GPS) with external aircraft antenna. A custom moving-map 

program developed by MMS project personnel in Visual Basic permitted surveyors to view the aircraft’s 

trackline in real time. 

Onboard safety equipment included an impact-triggered emergency locator transmitter installed in the aircraft, 

a 6-person Switlik Search and Rescue Life Raft equipped with a portable Personal Locator Beacon and 

desalination pump, a portable ICOM A3 Sport aircraft-band transceiver, an emergency Magellan 3000 GPS, 

White dry suits, and emergency flight helmets. 

In 2001, we used a Windstream Flight System for satellite-tracking the project aircraft over the Alaskan 

Beaufort Sea. The OAS obtained current flight information in the form of maps for visual tracking of the survey

aircraft. As a backup, we used an Iridium phone system as needed for communicating our position to OAS. In 

addition to these flight-following systems, the onboard transponder was set at a discrete identification code for 

radar tracking by air-traffic-control personnel. 

C. Aerial-Survey Design

Aerial surveys were based out of Deadhorse, Alaska, from 31 August through 19 October during 2001. Field 

schedules were designed to monitor the progress of fall bowhead migrations across the Alaskan Beaufort Sea. 

All bowhead (and beluga) whales observed were recorded, along with incidental sightings of other marine 

mammals. Particular emphasis was placed on regional surveys to assess large-area shifts in the migration 

pathway of bowhead whales and on the coordination of effort and management of data necessary to support 

seasonal offshore-drilling and seismic-exploration regulations. 

Daily flight patterns were based on sets of unique transect grids computer-generated for each survey block. 

Transect grids were derived by dividing each survey block into sections 30 minutes of longitude across. One 

of the minute marks along the northern edge of each section was selected at random then connected by a 

straight line to a similarly selected endpoint along the southern edge of that same section. This procedure was 

followed for all sections of that survey block. These transect legs were then connected alternately at their 

northernmost or southernmost ends to produce one continuous flight grid within each survey block. The use of

random-transect grids is a requirement for subsequent analyses of the bowhead migration corridor based on 

line-transect theory (Cochran, 1963). 

The selection of the survey blocks to be flown on a given day was nonrandom, based primarily on criteria such 

as reported or observed weather conditions over the study area and the level of offshore oil industry activity in 

various areas. Weather permitting, the project attempted to distribute effort fairly evenly east-to-west across 

the entire study area. It also used a semimonthly flight-hour goal for each survey block allocated 

proportionately for survey blocks east of 154°W. longitude and semimonthly time periods based on relative 

abundance of bowhead whales as determined from earlier fall migrations (1979-1986). Such allocations, 

detailed in our Project Management Plan (USDOI, MMS, 2001), greatly favor survey coverage in inshore 

Survey Blocks 1 through 7 and 11 (Fig. 1), since bowheads were rarely sighted north of these blocks in 

previous surveys. The purpose of these survey-effort allocations was to increase the sample size (n) of whale 

sightings within the primary migration corridor, thus increasing the power of statistical analysis within these 

inshore blocks. Only data from random-transect legs were used to analyze the migration axis, using a linetransect model. 

5
D. Survey-Flight Procedures

During a typical flight, a “search” leg was flown to the target survey block, beginning a series of random-

“transect” legs (above) joined together by “connect” legs, followed by a search leg back to Deadhorse. 

Surveys generally were flown at a target altitude of 458 m. Weather permitting, this altitude was maintained in 

order to maximize visibility and to minimize potential disturbance to marine mammals. Flights were normally

aborted when cloud ceilings were consistently less than 305 m or the wind force was consistently above 

Beaufort 4. 

Port observers included a Primary Observer, whose field of vision through a bubble window included the 

trackline directly below the aircraft to the horizon, the Pilot, and an occasional secondary observer-visitor, 

stationed aft at a flat window. Starboard observers included a Data Recorder-Observer, whose field of vision 

through a bubble window was particularly focused on guarding the trackline, as well as a Team Leader and a 

second Pilot, who were alternately stationed at an aft bubble window and the copilot’s seat. A clinometer was 

used to measure the angle of inclination to each sighting of endangered whales when the initial sighting 

location was abeam of the aircraft. 

When bowheads were encountered while surveying a transect line, the aircraft sometimes diverted from 

transect for brief (<10-minute) periods and circled the whales to observe behavior, obtain better estimates of 

their numbers, and determine whether calves were present. Any new sightings of whales made while circling

were not counted as “on transect.” Likewise, sightings made while en route to transect grids were counted as 

“on search”. 

E. Data Entry

A customized computer data-entry form developed by MMS project personnel was used to record all data in 

database format (Access 97). A multi-columnar data table permitted several entries of sighting and positionupdate data to be logged and edited simultaneously. The data-entry form is menu-driven, facilitating entry of a 

complete data sequence for sightings of whales. These data included date, time, latitude, longitude, altitude, 

aircraft heading, reason for entry, species, total number, observer, swim direction (magnetic), clinometer 

angle, calf number, behavior, sighting cue, predominant size, habitat, swim speed, repeat sighting, and 

response to aircraft. Reduced data sequences were used when recording other marine mammals. Positionupdate data on sky conditions, visual impediments, visibility left and right, percent ice coverage, ice type, and 

wind force were entered at sightings, turning points, when changes in environmental conditions were 

observed, and otherwise within 10-minute intervals. Entries were simultaneously printed out in hard copy. 

The behavior, swim speed, and swim direction for observed whales represent what the pod as a whole was 

doing at the time it was first sighted. Behaviors were entered into one of 15 categories as noted on previous 

surveys. These categories—breaching, cow-calf association, diving, feeding, flipper-slapping, log playing, 

mating, milling, resting, rolling, spy-hopping, swimming, tail-slapping, thrashing, and underwater blowing—are 

defined in Table 1. Swimming speed was subjectively estimated by observing the time it took a whale to swim

one body length. An observed swimming rate of one body length per minute corresponded to an estimated 

speed of 1 km/hr. One body length per 30 seconds was estimated at 2 km/hr, and so on. Swimming speed 

was recorded by relative category (i.e., still, 0 km/hr; slow, 0-2 km/hr; medium, 2-4 km/hr; or fast, >4 km/hr). 

Likewise, whale size was estimated relatively as calf (length less than half of accompanying adult), immature, 

adult, or large adult. Swim direction was initially recorded in magnetic degrees, using the aircraft's compass. 

Wind force was recorded according to the Beaufort scale outlined in Piloting, Seamanship, and Small Boat 

Handling (Chapman, 1971). Ice type was identified using terminology presented in Naval Hydrographic Office 

Publication Number 609 (USDOD, Navy, 1956). Average ice cover over a 1-2 km lateral distance from the 

aircraft was estimated as a single percentage, regardless of ice type. 

F. General Data Analyses

Preliminary field data analysis was performed by a computer program—developed by MMS project 

personnel—that provided daily summations of marine mammals observed, plus calculation of time and 

6
 Table 1 

Operational Definitions of Observed Whale Behaviors 

Behavior Definition

Breaching Whale(s) launching upwards such that half to nearly all of the body is above the surface 

before falling back into the water, usually on its side, creating an obvious splash. 

Cow-Calf Calf nursing; cow-calf pairs swimming within 20 m of each other. 

Diving Whale(s) changing swim direction or body orientation relative to the water surface, 

resulting in submergence; may or may not include lifting the tail out of the water. 

Feeding Whale(s) diving repeatedly in a fixed general area, sometimes with mud streaming from 

the mouth and/or defecation observed upon surfacing. Feeding behavior is further 

defined as synchronous diving and surfacing or echelon-formations at the surface with 

swaths of clearer water behind the whale(s), or as surface swimming with mouth agape 

FlipperSlapping 

Whale(s) floating on side, striking the water surface with pectoral flipper one or many 

times; usually seen within groups or when the slapping whale is touching another whale. 

Log-Playing Whale(s) milling or thrashing about in association with a floating log. 

Mating Ventral-ventral orienting of two whales, often with one or more other whales present to 

stabilize the mating pair. Mating is often seen within a group of milling whales. Pairs may

appear to hold each other with their pectoral flippers and may entwine their tails. 

Milling Whales moving slowly at the surface in close proximity (within 100 m) to other whales, 

often with varying headings. Also one whale slowly changing its heading. 

Resting Whale(s) floating at the surface with head, or head and back exposed, showing no 

movement; more commonly observed in heavy-ice conditions than in open water. 

Rolling Whale(s) rotating on the longitudinal axis, sometimes associated with mating. 

Spy-Hopping Whale(s) extending head vertically out of the water such that up to one-third of the body, 

including the eye, is above the surface. 

Swimming Whale(s) proceeding forward through the water propelled by tail pushes. 

Tail-Slapping Whale(s) floating horizontally or head-downward in the water, waving tail back and forth 

above the water and striking the water surface; usually seen in group situations. 

Thrashing Whale(s) exhibiting rapid flexure or gyration in the water. 

UnderwaterBlowing 

Whale(s) exhaling while submerged, thus creating a visible bubble. 

7
distance on transect legs, connect legs, and general search portions of the flight. This analysis program 

provided options for editing the data file, calculating summary values, and printing various flight synopses. 

Tables showing the number of survey hours flown for individual days, half-months, months, or survey blocks 

were subject to decimal-rounding errors and may or may not add up to the grand total shown for the entire 

field season. For greatest accuracy and consistency, the total survey hours shown in tables was calculated 

separately from the cumulative total minutes flown over the entire field season. 

The index of relative abundance used in report tables was calculated as whales per unit effort (WPUE), or the

number of whales counted per hour of survey effort on transect, connect, and search. Sighting rates used in 

report tables were derived as total sightings per unit effort (SPUE), or the number of whale pods sighted per 

hour of survey effort on transect, connect, and search. 

The water depth at each bowhead sighting in the 1982-2001 database was derived from the International 

Bathymetric Chart of the Arctic Ocean (IBCAO) containing grid cells 2.5 km square (website 

http://www.ngdc.noaa.gov/mgg/bathymetry/arctic/arctic.html. Selected isobaths (10 m, 20 m, 30 m, 40 m, 

50 m, 60 m, 100 m, 500 m, 1,000 m, 1,500 m, 2,000 m, 2,500 m, 3,000 m, and 3,500 m), also derived 

from IBCAO data, were included in Figure 2 for visual reference. 

The maps in this report were prepared with application software (ArcView 3.2a) based on Universal 

Transverse Mercator Zone 6 (central meridian =147°W. longitude, reference latitude 0.00000, false easting 

500000.00000, false northing 0.00000, spheroid = GRS 80, scale factor = 0.99960). The natural coastline was 

adopted from the State of Alaska, Department of Natural Resources. 

Sea-ice concentrations were derived from the Beaufort Sea Ice Analysis provided by the National Ice Center in

Suitland, Maryland. The Beaufort Sea Ice Analysis shows average ice concentrations over the prior 2- to 3-

day period based on visual, infrared, and synthetic-aperture-radar satellite imagery combined with 

reconnaissance, ship, and shore observations, including sea-ice observations made by the project. Polygons 

of ice concentrations in the Beaufort Sea bracketing the field seasons were downloaded from the National Ice 

Center Internet web site for the western Arctic (http://www.natice. noaa.gov) and imported into ArcView. Total 

sea-ice concentrations, regardless of ice type, were edited from these polygons and specially coded to 

distinguish 0-percent, 1- to 19-percent, 20- to 39-percent, 40- to 59-percent, 60- to 79-percent, 80- to 94-

percent, or 95- to 100-percent ice cover. 

Survey effort and observed bowhead distribution were plotted semimonthly over the Beaufort Sea study area. 

Overall fall sightings of beluga whales, as well as incidental sightings of other marine mammals, were depicted 

on separate maps. Common and scientific names used for marine mammals in this report are taken from Rice 

(1998). 

Overall, whale sightings were shown on distribution maps and entered into relative-abundance analyses, 

regardless of the type of survey leg (transect, search, or connect) being conducted or the prevailing 

environmental conditions (sea state, ice cover, etc.) when the sightings were made. As with previous reports 

in this series (Treacy, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 2000, and 2002), 

same-day repeat sightings or sightings of dead marine mammals were not included in summary analyses or 

maps. Where tables and figures exclude certain data, such exclusions are indicated in the captions. 

G. Analysis of the Bowhead Whale Migration Corridor

The corridor used by bowhead whales during their fall migration was analyzed both by the mean distance from 

shore to whales sighted on randomized transects as well as mean water depth at random whale sightings. 

The analyses presented here were completed using StatisticaTM StatSoft, Version 5.1 and ArcView 3.2a. The 

mean distance from shore at bowhead sightings between years were compared employing parametric analysis 

of variance (ANOVA) and Tukey “honestly significant difference” (HSD) tests. The ANOVA tests the 

hypothesis that distances from shore are the same among years. The Tukey HSD test is a multiple 

comparison procedure that provides statistical comparison of means for any pair of years (Zar, 1984). 

Distance from shore is of particular interest to North Slope residents who rely on a successful harvest of 

8
whales for subsistence purposes. Subsistence whalers generally agree that the farther offshore whales 

migrate, the riskier whales are to hunt and the more likely carcasses will spoil before reaching the villages 

(USDOI, MMS, 1997). 

An analysis protocol specifying the use of median water depth to detect interannual shifts in the bowhead 

migration route was initially described in Chapters 4.2.3 and 5.3.3 of “Beaufort Sea Monitoring Program 

Workshop Synthesis and Sampling Design Recommendations” (Houghton, Segar, and Zeh, 1984). Because 

of the bathymetry of the Alaskan Beaufort Sea, a seaward displacement of the fall-migration route would be 

represented, via this analysis, as a shift to deeper water and a greater median depth. 

The present analyses provide biological information needed to test the following null hypotheses 

recommended by the above workshop: 

Ho1: The axis of the fall migration of bowhead whales will not be altered during periods of increased OCS 

oil and gas development activities in the Alaskan Beaufort Sea. 

Ho2: Changes in bowhead migration patterns are not related to OCS oil and gas development activity. 

To determine the usefulness of these analyses for detecting differences in distance from shore between years, 

a preliminary power analysis was performed (Treacy, 1998). 

H. Sighting-Rate and Relative-Occurrence Maps

Maps of raw sighting points can give a misleading visual impression when survey effort is unequal. Because 

survey effort was unequal across our study area, due primarily to environmental conditions, a graphic method 

that adjusts for discontinuities in effort was desired. First, a grid matrix was superimposed across the study 

area using a Geographic Information System (ArcView, Version 3.2a). The matrix, consisting of approximately 

equilateral grid cells sized 5’ latitude by 15’ longitude, was considered appropriate to the data, simple to query, 

and visually easy to interpret. Bowhead sighting rates were calculated as the number of sightings per unit 

effort (SPUE) for each grid cell (5’ latitude by 15’ longitude) while on northerly-southerly transect. The index of 

relative occurrence of particular behaviors was calculated as the number of individual whales per unit effort 

(WPUE). The unit of effort for sighting-rate and relative occurrence maps was the number of kilometers (km) 

flown. Calculated rates were color-coded for quick visual comparison. 

I. Oceanographic Regions

To define the migration axis, a separate file was created for bowhead whale sightings made while on random 

transects, regardless of distance from the transect line. Distance from shore and water depth at bowhead 

whale sightings made during random transect aerial surveys in the Alaskan Beaufort Sea were analyzed for 

two regions (Fig. 2), the boundaries of which correspond roughly to oceanographic patterns and the offshoreextent of sampling. 

Oceanographic patterns common to waters offshore northern Alaska are reviewed in Moore and DeMaster 

(1997). In brief, cold saline Bering Sea water and warm fresh Alaskan coastal water enter the Alaskan 

Beaufort Sea through Barrow Canyon. Both water masses are identifiable on the outer shelf (seaward of 50 

m) as the eastward flowing Beaufort undercurrent (Aagaard, 1984). Bering Sea water has been traced at least 

as far east as Barter Island (~143°W.), but the Alaskan coastal water mixes with ambient surface waters as it 

moves eastward and is not clearly identifiable east of Prudhoe Bay (~147-148°W.). Therefore, the delineation 

between West-East regions for this analysis occurs at 148°W., based upon association with general patterns 

for these water masses. 

The northern extent of each region is based upon survey effort. For example, the East Region extends from 

140°W. to 148°W. and from the shore north to 71°10’ N., except between 146°W. and 148°W. where the 

region extends to 71°20’N. The northern boundary for this region corresponds with boundaries of survey 

blocks 6, 7 and 2 (Fig. 1): blocks with sufficient survey effort to support analyses (Treacy, 1997: Table 11). 

The West Region extends from 148°W. to 156°W. and from the shore north to 72°N., except between 148°W. 

9
                   

                   



  

























	





		

		

	

	





	





		

		

	

	



	











	




	 	
	


 



	

	












 


	




	 




		



	



	
  
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and 150°W. where the region extends to 71°20’N. due to the layout of Block 2. The eastern boundary 

(140°W.) is simply the easternmost longitude of the survey blocks. The western cutoff at 156°W. limits the 

analysis to bowheads seen in the Alaskan Beaufort Sea and avoids the influence of Barrow Canyon on 

bowhead depth distribution. 

The shoreline used for this analysis was ‘normalized’ from the actual Beaufort Sea shoreline to provide a 

standardization of distance-from-shore measures regardless of the mapping software being used to depict the 

distribution data. The ‘normalized’ shoreline was derived by connecting, with straight lines, eleven points at 

various shoreline or barrier islands locations across Alaska’s North Slope between 156°W. and 140°W. (Fig. 

2). The points used to ‘normalize’ the shoreline are as follows: 

71.317°N., 156.000°W. 

70.883°N., 153.900°W. 

70.917°N., 153.115°W. 

70.817°N., 152.200°W. 

70.430°N., 151.000°W. 

70.550°N., 150.167°W. 

70.450°N., 147.950°W. 

69.967°N., 144.700°W. 

70.150°N., 143.250°W. 

69.650°N., 141.000°W. 

69.617°N., 140.000°W. 

11
III. FALL 2001 RESULTS

A. Environmental Conditions

General sea-ice coverage in the Alaskan Beaufort Sea (Appendix A) varied considerably but was considered 

moderate overall during Fall 2001. Ice coverage began to open up after 27 August, with a narrow ice-free strip 

nearshore from Barrow to Flaxman Island by 3 September. Through the rest of September, most of the area 

within 100 nm of shore was either ice-free or less than 10% ice. By 1 October, the heavier offshore ice was 

closer to shore, lighter ice concentrations covered the area between Barrow and Deadhorse, and shorefast ice 

had begun forming west of Kaktovik. By 8 October, ice concentrations were generally heavy between Barrow 

and Deadhorse, with heavy shorefast ice east to Kaktovik. Ice concentrations were heavy all across the study

area throughout the rest of October. Ice percentages and sea states at each sighting of endangered whales 

are shown in Appendix B (Table B-1). 

Poor environmental conditions, primarily low cloud ceilings with occasional high sea states, limited the number 

of flights made during Fall 2001. Military flight restrictions were imposed from 11 through 14 September. 

B. Survey Effort

The fall field season was from 31 August 2001 through 19 October 2001. There were 23 flights, of which 15 

were in September and 8 were in October. Daily totals of kilometers and hours flown per survey flight during 

this period are shown in Table 2. A total of 16,996 km of surveys were flown in 72.93 hours in the study area 

at an average speed of 233.05 km/hr. The average survey flight was 738.96 km, with over-ocean flight 

distances ranging from 0 km to 1,605 km. A total of 8,572 km of random-transect lines were flown in 38.35 

hours at an average transect speed of 223.52 km/hr. These random transects constituted 50.44 percent of the 

total kilometers flown and 52.58 percent of the total flight hours. Survey-flight lines are shown by semimonthly

period in Figures 3 through 6. 

During the first half of September, survey coverage ranged from 140°W. to 157°W. longitudes, mostly within 

70 nautical miles (nm) of shore (Fig. 3). There were 20.65 hours of random transects flown out of 36.38 total 

flight hours during this period (Table 2), constituting 53.85 percent and 49.88 percent, respectively, of the total 

time spent in those effort categories over the fall season. 

During the second half of September, most survey coverage ranged from 143°W. to 149°W. longitudes, within 

50 nm of shore (Fig. 4). There were 5.05 hours of random transects flown out of 10.36 total flight hours during 

this period (Table 2), constituting 13.17 percent and 14.21 percent, respectively, of the total time spent in 

those effort categories. 

During the first half of October, survey coverage ranged from 143°W. to 157°W. longitudes, within 60 nm of 

shore (Fig. 5). There were 10.07 hours of random transects flown out of 20.14 total flight hours during this 

period (Table 2), constituting 26.26 percent and 27.62 percent, respectively, of the total time spent in those 

effort categories. 

From 16 through 19 October, survey coverage was limited to two flights with transect effort ranging from 

154°W. to 157°W. longitudes, within 70 nm of shore (Fig. 6). There were 2.58 hours of random transects flown 

out of 6.05 total flight hours during this period (Table 2), constituting 6.73 percent and 8.30 percent, 

respectively, of the total time spent in those effort categories. 

C. Bowhead Whale (Balaena mysticetus) Observations

1. Sighting Summary: Twenty-nine sightings were made for a total of 35 bowhead whales observed 

during Fall-2001 surveys in the study area (Table 3 and Figs. 7-9). Relatively widespread survey coverage 

between 140°W. and 157°W. longitudes (Figs. 3-6) showed bowhead whales distributed between 140°W. and 

153°W. longitudes on the continental shelf within 40 nm north of the shoreline, unadjusted for effort (Fig. 9). 

Two of the 35 whales were identified as calves (Appendix B: Table B-1), resulting in a seasonal calf ratio 

(number calves/total whales) of 0.057. A semi-monthly analysis follows. 

13
Table 2 

Aerial-Survey Effort in the Beaufort Sea, 31 August–19 October 2001, by Survey Flight 

Day

Flight 

No. 

Transect 

(km)

Connect 

(km)

Search 

(km)

Total 

(km)

Transect 

(hr) 

Total 

(hr) 

2 Sep 1 0 0 496 496 0.00 1.85 

3 Sep 2 0 0 0 0 0.00 0.00 

5 Sep 3 431 138 404 972 2.02 4.32 

6 Sep 4 754 166 480 1,399 3.28 6.08 

7 Sep 5 585 109 289 982 2.57 4.30 

8 Sep 6 0 0 272 272 0.00 1.10 

9 Sep 7 825 121 529 1,474 3.70 6.33 

10 Sep 8 1,223 107 275 1,605 5.33 7.00 

15 Sep 9 830 138 254 1,221 3.75 5.40 

16 Sep 10 0 0 202 202 0.00 0.77 

22 Sep 11 361 91 103 555 1.60 2.45 

24 Sep 12 0 0 22 22 0.00 0.08 

26 Sep 13 235 65 314 613 1.10 2.63 

29 Sep 14 246 66 85 397 1.12 1.75 

29 Sep 15 267 81 273 621 1.23 2.68 

2 Oct 16 667 174 209 1,050 3.02 4.58 

3 Oct 17 68 0 614 682 0.28 2.68 

4 Oct 18 0 0 230 230 0.00 0.88 

7 Oct 19 583 146 243 972 2.62 4.20 

12 Oct 20 388 96 93 577 1.70 2.50 

13 Oct 21 552 60 630 1,241 2.45 5.30 

16 Oct 22 0 0 170 170 0.00 0.68 

19 Oct 23 557 109 578 1,243 2.58 5.37 

Semimonthly Effort Summary 

1-15 Sep 4,648 779 2,999 8,421 20.65 36.38 

16-30 Sep 1,109 303 999 2,410 5.05 10.36 

1-15 Oct 2,258 476 2,019 4,752 10.07 20.14 

16-19 Oct 557 109 748 1,413 2.58 6.05 

TOTAL 8,572 1,667 6,765 16,996 38.35 72.93 

14
Table 3 

Summary of Marine Mammal Sightings, 31 August-19 October 2001, by Survey Flight 

(number of sightings/number of animals) 

Day 

Flight 

No. 

Bowhead 

Whale 

Gray 

Whale 

Beluga 

Whale 

Unidentified

Cetacean 

Bearded

Seal 

Ringed 

Seal 

Pacific 

Walrus 

Unidentified 

Pinniped 

2 Sep 1 0 0 0 0 0 0 0 0 3 Sep 2 0 0 0 0 0 0 0 0 5 Sep 3 11/12 0 0 0 0 5/9 0 0 6 Sep 4 2/3 0 6/16 0 7/7 6/7 0 0 7 Sep 5 7/10 0 6/45 1/1 1/1 1/1 0 2/2 8 Sep 6 0 0 0 0 1/1 0 0 0 9 Sep 7 0 5/6 18/143 1/1 1/1 3/3 0 0 

10 Sep 8 4/4 0 11/29 0 0 6/8 0 0 15 Sep 9 0 0 21/123 0 0 3/8 0 0 16 Sep 10 0 0 0 0 0 0 0 0 22 Sep 11 0 0 0 0 1/1 4/5 0 1/1 24 Sep 12 0 0 0 0 0 0 0 0 26 Sep 13 0 0 0 0 0 0 0 0 29 Sep 14 0 0 0 0 0 0 0 0 29 Sep 15 0 0 0 0 0 0 0 0 

2 Oct 16 5/6 0 5/13 0 0 0 0 0 3 Oct 17 0 0 0 0 0 0 0 0 4 Oct 18 0 0 0 0 0 0 0 0 7 Oct 19 0 0 0 0 0 1/1 0 0 

12 Oct 20 0 0 0 0 0 0 0 0 13 Oct 21 0 0 1/1 0 0 0 0 0 16 Oct 22 0 0 0 0 0 0 0 0 19 Oct 23 0 0 2/16 0 0 0 0 0 

Total Semimonthly Sightings 

1-15 Sep 24/29 5/6 62/356 2/2 10/10 24/36 0 2/2 

16-30 Sep 0 0 0 0 1/1 4/5 0 1/1 

1-15 Oct 5/6 0 6/14 0 0 1/1 0 0 

16-19 Oct 0 0 2/16 0 0 0 0 0 

TOTAL 29/35 5/6 70/386 2/2 11/11 29/42 0 3/3 

15
                   

                   



  

























	





		

		

	

	





	





		

		

	

	



	











	




	 	
	


 



	

	












 


	




	 




		



	



	
  
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21
22
During the first half of September, 24 sightings were made for a total of 29 bowheads (Table 3), with sightings

ranging between 140°W. and 153°W. longitudes mostly within 30 nm north of the shoreline (Fig. 7), based on 

survey coverage across the study area (Fig. 3). The first bowheads observed in the Alaskan Beaufort Sea 

were sighted on 5 September at 69°53.6 ́N. latitude, 140°21.5 ́W. longitude. Pod sizes ranged from 1 to 3 

whales, with a mean of 1.21 (SD=0.51, n=24). One bowhead whale calf was observed during this period 

(Appendix B: Table B-1). 

During the second half of September, no bowhead whales were sighted (Table 3), based on limited survey 

coverage between Oliktok Point and Kaktovik, Alaska (Fig.4). 

During the first half of October, 5 sightings were made for a total of 6 bowheads (Table 3), with sightings 

clustered between 143°W. and 148° ́W. longitudes within 20 nm north of the shoreline (Fig. 8), based on 

widespread survey coverage from Barrow to Kaktovik, Alaska (Fig. 5). Pod sizes ranged from 1 to 2 whales, 

with a mean of 1.20 (SD=0.45, n=5). One bowhead whale calf was observed during this period. The last 

bowhead whales in the Alaskan Beaufort Sea were sighted on 2 October at 70°27.1 ́N. latitude, 147°07.4 ́W. 

longitude (Appendix B: Table B-1). 

From 16 through 19 October, no bowhead whales were sighted (Table 3), based on limited survey coverage 

between Barrow and Flaxman Island, Alaska (Fig. 6). 

 2. Sighting Rates: In Fall 2001, bowhead sighting rates between Demarcation Point and Flaxman 

Island, Alaska, were highest in an east-west band within 30 nm from shore between 140°W. and 143° ́W. 

longitudes. Other high sighting rates, scattered between Cape Halkett and Kaktovik, Alaska, were more 

isolated (Fig. 10). 

3. Migration Timing: Temporal sighting rates (SPUE) were calculated over the entire study area as the

number of sightings made per hour while on search, connect, and transect. These hourly sighting rates 

(regardless of survey-effort type), were calculated by survey day during the Fall-2001 bowhead whale 

migration to identify any obvious temporal patterns. Of the 29 sightings of bowhead whale pods, the first 

whale observed was on 5 September. Due to poor sighting conditions, daily sighting rates per hour were 

spotty and therefore inconclusive over the field season. No whales (0.00 SPUE) were sighted on 17 separate 

flight days. The greatest number of sightings (2.55 SPUE) occurred on 5 September. The last sighting of a 

bowhead whale was made on 2 October (Table 4). 

The index of relative abundance was calculated over the entire study area as the number of individual animals 

counted per hour while on search, connect, and transect. This index by survey day was also used to identify 

any obvious temporal patterns. Of the 35 individual bowhead whales counted, the data for daily relative 

abundance show that the midpoint (median) of the bowhead migration in Blocks 1 through 12 (when 50% of all 

sighted whales had been recorded) occurred on 7 September. The peak relative abundance (mode) of 2.78 

WPUE also occurred on 5 September (Table 4). 

There were no prominent differences in temporal pattern between sighting rates and the index for relative 

abundance, due to a lack of large pods or aggregations of whales observed during the field season (Appendix 

B: Table B-1). 

4. Habitat Associations: In addition to general ice coverage for arctic waters during Fall 2001 

(Appendix A), the percentage of ambient ice cover visible from the aircraft at each bowhead sighting 

(Appendix B: Table B-1) was summarized. Of the 35 bowheads counted over the field season, 28 whales 

(80%) were sighted in open water, 5 (14%) whales were observed in 1-5% sea ice, and 1 whale each (3%) 

was counted in 6-10% and 11-20% sea ice. When general ice cover increased during October (Appendix A), 

only 6 whales (all in open water) were counted (Table 5). Observing fewer whales in heavy ice concentrations 

is expected given the reduced counts of bowheads per unit effort noted for those years of increased general 

sea-ice severity (Treacy, 1998: Table 13). 

23
Table 4 

Number of Sightings and Total Bowhead Whales Observed per Hour, 

31 August-19 October 2001, by Flight Day 

Day

No. of 

Sightings 

No. of 

Whales 

Survey

Time (hr) 

Sightings/hr 

(SPUE) 

Whales/hr 

(WPUE) 

2 Sep 0 0 1.85 0.00 0.00 

3 Sep 0 0 0.00 0.00 0.00 

5 Sep 11 12 4.32 2.55 2.78 

6 Sep 2 3 6.08 0.33 0.49 

7 Sep 7 10 4.30 1.63 2.33 

8 Sep 0 0 1.10 0.00 0.00 

9 Sep 0 0 6.33 0.00 0.00 

10 Sep 4 4 7.00 0.57 0.57 

15 Sep 0 0 5.40 0.00 0.00 

16 Sep 0 0 0.77 0.00 0.00 

22 Sep 0 0 2.45 0.00 0.00 

24 Sep 0 0 0.08 0.00 0.00 

26 Sep 0 0 2.63 0.00 0.00 

29 Sep 0 0 4.43 0.00 0.00 

2 Oct 5 6 4.58 1.09 1.31 

3 Oct 0 0 2.68 0.00 0.00 

4 Oct 0 0 0.88 0.00 0.00 

7 Oct 0 0 4.20 0.00 0.00 

12 Oct 0 0 2.50 0.00 0.00 

13 Oct 0 0 5.30 0.00 0.00 

16 Oct 0 0 0.68 0.00 0.00 

19 Oct 0 0 5.37 0.00 0.00 

24
Table 5 

Semimonthly Summary of Bowhead Whales Observed, 

by Percent Ice Cover Present at Sighting Location, Fall 2001 

% Ice Cover 1-15 Sep 16-30 Sep 1-15 Oct 16-19 Oct Total 

0 22 (77%) 0 6 (100%) 0 28 (80%) 

1-5 5 (17%) 0 0 0 5 (14%) 

6-10 1 (3%) 0 0 0 1 (3%) 

11-20 1 (3%) 0 0 0 1 (3%) 

21-30 0 0 0 0 0

31-40 0 0 0 0 0

41-50 0 0 0 0 0

51-60 0 0 0 0 0

61-70 0 0 0 0 0

71-80 0 0 0 0 0

81-90 0 0 0 0 0

91-99 0 0 0 0 0

TOTAL 29 (100%) 0 (100%) 6 (100%) 0 (100%) 35 (100%) 

Table 6 

Semimonthly Summary of Bowhead Whales Observed, by Behavioral Category, Fall 2001 

Behavior 1-15 Sep 16-30 Sep 1-15 Oct 16-19 Oct Total 

Breaching 2 (7%) 0 0 0 2 (6%) 

Cow-Calf 2 (7%) 0 0 0 2 (6%) 

Resting 5 (17%) 0 0 0 5 (14%) 

Swimming 20 (28%) 0 6 (100%) 0 26 (74%) 

(not noted) 0 0 0 0 0

TOTAL 29 (100%) 0 (100%) 6 (100%) 0 (100%) 35 (100%) 

25
                   

                   



  

























	





		

		

	

	





	





		

		

	

	



	











	




	 	
	


 



	

	












 


	




	 




		



	



	
  
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5. Behaviors: Of 35 bowhead whales observed during Fall 2001, 26 (74%) were swimming (traveling 

forward in an apparently deliberate manner), 5 (14%) were resting, 2 (6%) were breaching, and 2 (6%) were 

relating to each other as cow and calf when first sighted (Table 6). These behaviors are defined in Table 1. 

Sudden overt changes (e.g., an abrupt dive, course diversion, or cessation of behavior ongoing) in whale 

behavior were looked for. No bowheads were observed for which responses to the survey aircraft were noted. 

6. Distance from Shore: Distances from shore of Fall-2001 bowhead whale sightings made on 

transect were measured by ArcView 3.2 as the distance due north of a normalized shoreline. The mean 

distance from shore and Standard Deviations (SD) for an East and West Region were calculated (Table 7) and 

mapped (Fig. 11). This mean distance for bowhead whales was 31.5 km in the East Region, with little 

variation (SD=10.8 km), and 43.4 km in the West Region, with wide variation (SD=43.2 km). 

D. Other Marine Mammal Observations

1. Gray Whale (Eschrichtius robustus): Over the 2001 season, there were 5 sightings for a total of 6

gray whales. These whales were sighted on 9 September near Barrow, Alaska (Table 3 and Fig. 12). 

2. Beluga Whale (Delphinapterus leucas): Although the study area and survey altitude were 

designed to record the fall migration of bowhead whales, beluga whales, which undertake a somewhat parallel 

migration farther offshore, were readily observable and were always counted. Over the Fall-2001 field season,

70 sightings were made for a total of 386 beluga whales (Table 3) during 72.93 hr of total survey effort (Table 

2), for a seasonal relative abundance of 5.29 WPUE. Beluga whales were noted from 6 September through 

19 October, all across the study area (141°W. and 157°W. longitudes). Sightings east of 155°W. longitude 

were along the continental slope, mostly between 40 and 90 nm from shore (Fig. 13). Twenty-two beluga 

calves were noted for a calf ratio of 0.057. Most of the belugas (64%) were in less than 20% concentration of 

ambient sea ice. 

3. Bearded Seal (Erignathus barbatus nauticus): Over the 2001 season, 11 incidental sightings were 

made for a total of 11 bearded seals (Table 3). All but one bearded seal sighting was made east of 147°W. 

longitude. All were on the continental shelf, mostly within 30 nm of shore (Fig. 14). 

4. Ringed Seal (Pusa hispida hispida): Over the 2001 season, 29 incidental sightings were made for 

a total of 42 ringed seals (Table 3). Sightings were made all across the study area. Almost all were on the 

continental shelf within 60 nm of shore (Fig.15). 

5. Walrus (Odobenus rosmarus divergens): Over the 2001 season, no incidental sightings were 

made (Table 3). 

6. Unidentified Cetaceans and Pinnipeds: Over the 2001 season, there was 1 incidental sighting for

a total of 6 unidentified pinnipeds and 1 incidental sighting of an unidentified cetacean (Table 3). 

7. Polar Bear (Ursus maritimus marinus): Over the 2001 season, 4 incidental sightings were made 

for a total of 6 polar bears (Table 3). The bears were on 98-100% concentrations of sea ice between 140°W. 

and 155°W. longitudes (Fig. 16). In addition to sightings of polar bears, 43 sets of polar bear tracks were 

noted for which no bear was present (Table 3 and Fig. 17). 

27
                   

                   



  



 

 





















 

	











	




	 	
	


 

	

	












 


	




	 




		



	



	
  
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34
IV. INTERANNUAL RESULTS

A. Statistical Analyses of Bowhead Whale Sighting Distribution (1982-2001)

1. Central Tendency Statistics - Distance from Shore: Transect data were analyzed over a 20-year 

period (1982-2001) in two regions of the Alaskan Beaufort Sea (Fig. 2). Annual central-tendency statistics for 

distance of bowhead whales from shore were summarized by year and region (Table 7). The mean distance 

of whale sightings from shore in each region was also depicted visually for Fall 2001 (Fig. 11). 

East Region

The combined data (1982-2001) included 709 transect sightings (trSI) in the East Region. Mean measures of 

distance from shore among years ranged from 15.1 km (in 1997) to 89.7 km (in 1983). The Confidence 

Interval (CI) about the mean was widest (>30 km) in 1988 and 1989, when annual sample sizes were small 

(<10 trSI) (Table 7). 

West Region

The combined data (1982-2001) included 605 transect sightings in the West Region. Mean measures of 

distance from shore ranged from 17.7 km (in 2000) to 65.9 km (in 1988). The Confidence Interval (CI) about 

the mean was widest (>30 km) in 1985, 1987, 1990, 1991, and 1994, when annual sample sizes were small 

(<10 trSI) (Table 7). 

2. Central Tendency Statistics - Water Depth: The transect data were analyzed over a 20-year period

(1982-2001) in two regions of the Alaskan Beaufort Sea (Fig. 2). Annual central-tendency statistics for water 

depth at bowhead whale sightings were summarized by year and region (Table 8). 

East Region

The combined data (1982-2001) included 709 transect sightings in the East Region. Annual mean depths 

ranged from 23.9 m (in 1997) to 915.5 m (in 1983). The CI about the mean was widest (>100 m) in 1983, 

1988, 1989, 1991 and 1994, four years of which had small sample sizes (<20 trSI). The 25th - 75th quartiles 

about the median were widest apart (>35 m) in 1983, 1989, and 1991 (Table 8). 

West Region

The combined data (1982-2001) included 605 transect sightings in the West Region. Annual mean depths 

ranged from 18.7 m (in 1989) to 312.7 m (in 1983). The CI about the mean was widest (>100 m) in 1982, 

1983, 1985, 1986, 1991, 1992, and 1995, four years of which had small sample sizes (<20 trSI). The 25th-75th

quartiles about the median were widest apart (>35 m) in 1983, 1985, 1986, and 1991 (Table 8). 

3. ANOVA - Distance from Shore: A parametric ANOVA of distances from shore over a 20-year 

period (1982-2001) indicated strongly significant differences among years for the East Region (F=18.5 (19, 709); 

p<0.01) and for the West Region (F=10.0 (19, 605); p<0.0001). A preliminary power analysis of the ANOVA 

(α=0.05, β≤0.01), comparing only those years from 1982 through1997 having a larger sample size (n≥20 trSI), 

showed minimum detectable differences of 7.8 km in the East Region and 9.7 km in the West (Treacy, 1998). 

4. Tukey HSD Test - Distance from Shore: Since the ANOVA showed significant differences among 

years, the Tukey HSD test was applied to all transect sightings of bowhead whales over a 20-year period 

(1982-2001) without exclusions to determine which years were significantly different from each other. 

East Region

The Tukey test showed that bowheads in 1983 migrated significantly (p<0.05) farther offshore than in any 

other year except 1989. The data also showed that whales in 1989 and 1991 were significantly farther 

offshore, and in 1997, and 1998 were significantly nearer to shore, than for most (>10) other years. 

35
 Table 7 

Central-Tendency Statistics for Distance from Shore (in kilometers) to Random Sightings 

of Bowhead Whales (September-October), by Year and Region, 1982-2001

Year Region trSI 

1

Median 

25th-75th

Quartile 

Range 

Mean SD 

2 

CI 

3

Range 

1982 East 28 36.9 31.5-43.2 38.2 8.5 34.9-41.5 26.0-56.6 

West 26 41.7 37.7-48.9 43.7 16.7 36.9-50.4 14.6-86.3 

1983 East 14 89.5 82.0-98.9 89.7 15.7 80.7-98.8 59.6-121.2 

West 15 53.3 42.3-86.6 62.2 26.3 47.6-76.7 27.5-125.3 

1984 East 23 36.6 25.6-56.5 39.7 23.9 29.3-50.0 1.9-103.4 

West 36 46.2 36.8-60.3 45.7 19.2 39.2-52.2 8.9-85.2 

1985 East 10 29.5 23.7-40.5 31.8 16.0 20.4-43.3 1.9-61.4 

West 7 50.3 25.9-86.3 53.8 29.2 26.8-80.8 15.4-88.9 

1986 East 30 27.5 16.7-39.8 27.8 16.7 21.5-34.0 1.0-58.1 

West 19 38.8 24.7-52.4 39.9 22.8 28.9-50.9 3.7-81.7 

1987 East 30 33.5 18.5-50.1 37.0 20.7 29.3-44.7 6.9-86.1 

West 8 29.2 16.7-51.2 32.7 20.2 15.9-49.6 7.4-60.3 

1988 East 6 29.5 24.4-33.9 33.4 23.5 8.8-58.0 6.4-76.8 

West 8 64.5 59.1-71.4 65.9 11.2 56.6-75.3 50.7-86.8 

1989 East 6 55.8 49.3-89.4 63.4 23.4 38.8-87.9 36.1-94.0 

West 17 35.4 15.6-45.8 32.8 19.4 22.8-42.8 7.5-74.5 

1990 East 93 33.8 25.4-43.0 34.5 13.8 31.7-37.4 8.1-78.6 

West 6 35.8 32.3-48.2 42.5 18.5 23.1-61.9 25.9-77.3 

1991 East 15 56.0 38.8-76.7 56.7 22.0 44.6-68.9 22.0-85.6 

West 6 46.0 34.1-72.3 51.5 18.8 31.7-71.2 33.6-76.8 

1992 East 12 38.2 34.3-51.6 42.5 10.9 35.6-49.4 28.5-60.5 

West 13 61.1 45.1-74.3 59.3 17.2 48.9-69.7 29.9-82.2 

1993 East 55 30.3 21.2-40.4 31.9 17.0 27.3-36.5 6.4-88.4 

West 35 25.1 20.4-38.6 29.9 12.7 25.6-34.3 11.8-62.7 

1994 East 32 29.4 22.4-56.2 37.2 18.7 30.4-44.0 13.9-77.7 

West 3 23.3 4 24.8 11.5 4 14.1-36.9 

36
 Table 7 

 Central-Tendency Statistics for Distance from Shore (in kilometers) to Random Sightings 

of Bowhead Whales (September-October), by Year and Region, 1982-2001

Year Region trSI 

1 

Median 

25th-75th

Quartile 

Range 

Mean SD 

2 

CI 

3 

Range 

1995 East 94 30.2 23.6-41.6 33.1 16.4 29.7-36.5 3.7-99.5 

West 44 36.5 25.3-51.7 42.9 26.5 34.8-50.9 7.6-118.7 

1996 East 13 29.4 21.0-34.6 29.1 11.4 22.2-36.0 15.3-57.6 

West 15 40.6 23.6-55.1 40.8 14.8 32.6-49.1 21.4-64.1 

1997 East 35 10.2 5.9-20.4 15.1 11.9 11.0-19.1 3.4-44.9 

West 145 27.4 20.0-36.3 29.2 13.0 27.1-31.3 1.0-66.0 

1998 East 103 22.2 13.6-31.3 23.8 13.0 21.3-26.3 4.0-73.8 

West 113 20.9 14.7-32.5 26.3 18.6 22.8-29.8 1.1-124.0 

1999 East 68 40.2 28.5-49.7 39.5 13.5 36.3-42.8 -0.15

-65.8

West 68 36.1 27.0-52.1 39.3 17.5 35.1-43.6 9.2-75.6 

2000 East 26 39.3 28.7-52.1 43.5 22.7 34.3-52.7 13.9-108.8 

West 19 11.0 4.7-25.3 17.7 19.2 8.5-27.0 0.02-80.8 

2001 East 16 33.9 22.7-39.5 31.5 10.8 25.7-37.2 13.5-49.8 

West 2 42.4 4 42.4 43.2 4 11.8-73.0 

Cumulative East 709 32.1 21.0-43.3 34.4 19.2 33.0-35.8 -0.15

-121.2

(1982-2001) West 605 32.5 20.2-47.1 35.4 20.5 33.8-37.1 0.02-125.3 

1

 trSI = number of transect sightings. 

2

 SD = standard deviation. 

3

 CI ≥ 95-percent confidence interval (positive values). 

4

 Insufficient sample size. 

5

 Negative value is for one transect sighting between the actual and normalized coastline. 

37
 Table 8 

Central-Tendency Statistics for Water Depth (in meters) at Random Sightings 

of Bowhead Whales (September-October), by Year and Region, 1982-2001

Year Region trSI 

1

Median 

25th-75th

Quartile 

Range 

Mean SD 

2

CI 

3

Range 

1982 East 28 42.1 38.6-49.0 43.5 6.4 41.0-46.0 34.9-57.3 

West 26 30.3 22.8-37.4 94.0 210.9 8.9-179.2 14.3-1041.5 

1983 East 14 804.0 263-1779 915.5 718.8 501-1331 64.6-1952.8 

West 15 68.3 33.7-209.1 312.7 597.9 18.4-643.9 20.7-2165.7 

1984 East 23 43.9 35.2-54.3 77.0 104.8 31.7-122.3 17.8-507.9 

West 36 40.3 31.7-55.6 47.7 33.2 36.5-59.0 12.8-189.2 

1985 East 10 38.3 34.8-40.8 37.5 7.4 32.3-42.8 22.8-51.0 

West 7 35.7 23.9-148.1 193.3 348.5 129-515.6 16.1-974.7 

1986 East 30 41.1 24.0-50.2 38.1 18.2 31.4-44.9 6.8-91.5 

West 19 28.3 18.9-75.1 77.9 117.4 21.3-134.6 9.6-489.7 

1987 East 30 39.7 32.7-54.3 56.3 47.9 38.4-74.2 14.9-223.3 

West 8 25.2 13.1-31.6 22.6 10.0 14.2-30.9 8.3-32.4 

1988 East 6 48.8 39.1-50.3 92.2 123.5 37.3-221.8 22.9-343.4 

West 8 49.4 46.9-52.7 50.3 6.8 44.6-55.9 40.5-63.5 

1989 East 6 60.5 51.1-448.4 196.1 219.7 34.5-426.7 47.3-508.8 

West 17 20.1 11.3-24.1 18.7 8.1 14.5-22.8 5.8-33.8 

1990 East 93 42.0 35.9-50.1 47.7 33.0 40.9-54.5 19.6-284.6 

West 6 31.5 22.8-39.2 32.6 11.4 20.6-44.6 20.0-50.6 

1991 East 15 54.6 49.8-190.7 122.1 108.4 62.1-182.1 34.8-387.0 

West 6 41.5 35.5-204.8 96.6 94.2 2.2-195.5 26.3-230.2 

1992 East 12 53.5 47.1-56.0 51.5 6.0 47.7-55.3 40.5-58.9 

West 13 50.8 43.9-53.6 54.1 27.8 37.3-70.8 14.3-121.3 

1993 East 55 40.5 33.5-50.2 58.4 96.5 32.3-84.5 11.4-716.6 

West 35 20.1 16.4-25.4 22.8 9.4 19.6-26.0 10.7-49.3 

1994 East 32 46.8 39.0-53.3 79.8 175.6 16.5-143.1 30.7-1037.8 

West 3 12.0 4 21.4 16.6 4 11.6-40.5 

38
 Table 8 

Central-Tendency Statistics for Water Depth (in meters) at Random Sightings 

of Bowhead Whales (September-October), by Year and Region, 1982-2001

Year Region trSI 

1 

Median 

25th-75th

Quartile 

Range 

Mean SD 

2 

CI 

3 

Range 

1995 East 94 41.4 35.7-49.9 52.5 68.7 38.4-66.6 14.9-628.0 

West 44 30.8 25.8-38.8 107.4 259.7 28.4-186.4 6.5-1232.8 

1996 East 13 39.4 33.4-45.6 37.7 9.3 32.1-43.3 15.0-48.5 

West 15 34.8 23.6-44.3 37.0 17.1 27.5-46.5 18.6-82.5 

1997 East 35 22.1 13.0-32.0 23.9 11.9 19.8-28.0 10.5-50.0 

West 145 20.0 15.7-26.5 25.0 21.4 21.5-28.5 4.7-189.2 

1998 East 103 32.4 26.1-40.3 34.2 12.0 31.9-36.6 6.6-82.6 

West 113 15.2 11.6-21.5 37.7 170.8 5.9-69.6 5.4-1814.7 

1999 East 68 50.2 39.5-54.6 51.2 20.9 46.2-56.3 7.9-171.3 

West 68 30.7 21.1-41.9 42.6 42.9 32.2-53.0 10.9-210.3 

2000 East 26 40.6 36.3-56.9 81.6 122.0 32.3-130.9 28.4-108.8 

West 19 11.3 6.8-19.6 31.5 81.5 7.8-70.8 4.0-366.8 

2001 East 16 45.6 38.2-49.7 42.8 8.7 38.2-47.5 26.7-52.7 

West 2 28.8 4 28.8 26.2 4 10.3-47.3 

Cumulative East 709 40.9 33.7-50.6 69.8 170.2 57.2-82.3 6.6-1952.8

(1982-2001) West 605 23.9 15.8-36.0 52.3 158.9 39.6-65.0 4.0-2165.7 

1

 trSI = number of transect sightings. 

2

 SD = standard deviation. 

3

 CI ≥ 95-percent confidence interval (positive values). 

4

 Insufficient sample size. 

39
West Region

The Tukey test showed that bowheads in 2000 migrated significantly (p<0.05) nearer to shore than for most 

(>10) other years. 

B. General Sea Ice Severity (1979-2001)

General ice coverage along the northern coast of Alaska during the 2001 navigation season was the 35thmildest for the 49 years from 1953 through 2001 and showed a distance of 25 nm from Point Barrow 

northward to the boundary of 5-tenths ice concentration on 15 September (USDOC, NOAA, National Ice 

Center/USDOD, Navy, Naval Ice Center, 2002). 

The years 1980, 1983, 1988, and 1991 were categorized as having “heavy” ice cover during the navigation 

season. These 4 years are ranked as having the severest seasonal ice for the years 1979 through 2001 and 

showed distances ranging from 10 to 25 nm between Point Barrow and the five-tenths ice concentration on 15 

September (USDOC, NOAA, National Ice Center/USDOD, Navy, Naval Ice Center, 2002). 

The years 1984, 1985, 1992 and 2001, categorized as having “moderate” ice cover during the open-water 

season, are ranked next in seasonal ice severity for the years 1979 through 2001 and showed distances 

ranging from 25 to 75 nm between Point Barrow and the five-tenths ice concentration on 15 September 

(USDOC, NOAA, National Ice Center/USDOD, Navy, Naval Ice Center, 2002). 

The years 1979, 1981, 1982, 1986, 1987, 1989, 1990, and 1993-2000, categorized as having “light” ice cover

during the open-water season, are ranked as having the least-severe seasonal ice for the years 1979 through 

2001 and showed distances ranging from 50 to 240 nm between Point Barrow and the five-tenths ice 

concentration on 15 September (USDOC, NOAA, National Ice Center/USDOD, Navy, Naval Ice Center, 2002). 

Previous analysis of sighting rates for the years 1982-2000 showed 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 factors other 

than sea ice 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 (Treacy, 2002). 

C. Fall Spatial Variation in Bowhead Whale Feeding and Milling Activity (1982-2001)

A Geographic Information System (ArcView, Version 3.2a) was used to identify temporal or spatial patterns in

feeding or milling behavior of bowhead whales in a given year or multiple years. Data obtained on north-south 

transects were used to ensure parallel, somewhat even survey effort across the study area and as a basis for 

an index of the relative occurrence of particular behaviors. To maximize the number of whales observed on 

transect, whales observed in all environmental conditions were included. 

Whales that were either feeding or milling (as defined in Table 1) when first observed were considered. 

Obvious surface cues such as mud plumes and open mouths, while useful for inferring bottom and surface 

feeding, are not always observable when the food source (e.g., copepods) is located midway in the water 

column. When whales engaged in mid-water feeding surface to breathe, their behavior would likely be 

recorded as milling by observers on dedicated aerial transects, with limited opportunity to circle whales. To be 

inclusive, milling whales were considered along with apparent feeding behaviors, even though some milling 

whales were probably 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 the relative occurrence of these behaviors in the Alaskan Beaufort Sea. The index of relative 

occurrence was based on the numbers of whales observed per kilometer while on northerly-southerly 

transects during our September-October surveys within grid cells where transect effort took place. This 

measure was used to identify locations of lower (0.01-0.099 WPUE), moderate (0.1-0.999 WPUE), and higher 

(1.0 WPUE or greater) relative behavioral occurrence. Figure 18 is the most recent map for which feeding 

40
                   

                   



  

























	





		

		

	

	





	





		

		

	

	



	











	




	 	
	


 



	

	












 


	




	 




		



	



	
  
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41
and/or milling behaviors were noted (2000). Data pooled by decade were also mapped (Appendix D). 

Greater relative occurrence of feeding and/or milling behaviors of bowhead whales was observed on 

transect in six of the 20 years (1984, 1989, 1997, 1998, 1999 and 2000) near the mouth of Dease Inlet, 

Alaska. During 1992, we also noted large aggregations of bowhead whales (not on transect) feeding in 

this same location, and how the center of that feeding activity moved westward in late October (Landino et 

al. 1994). Greater relative occurrence of feeding and/or milling behaviors of bowheads was observed on 

transect in four of those years (1989, 1997, 1998 and 1999) near Cape Halkett, Alaska. The pooled-data 

map for the 1990’s reflects the higher relative occurrence of feeding and milling whales from Dease Inlet to 

Harrison Bay (1997-1999). There were nine other years when feeding and/or milling behaviors were 

noted on transect but not near Dease Inlet or Cape Halkett (1982, 1983, 1985, 1986, 1988, 1990, 1993, 

1995, and 1996). Such relative occurrence was typically spottier, less recurrent between years, and/or 

involved fewer whales per unit effort. In five other years (1987, 1991, 1992, 1994, and 2001), neither 

feeding nor milling behaviors were observed on transect anywhere in the study area (Appendix D). 

Inter-annual and geographic variation in prey availability likely accounts for opportunistic feeding 

aggregations in particular years and locations. A greater relative occurrence of bowhead feeding and 

milling behaviors from Dease Inlet to Harrison Bay during 1997 might have been linked with higher prey

availability, possibly associated with a narrow band of warmer-than-average sea surface temperatures 

during that El Niño year (Treacy, 1998). Because mud plumes were often associated with the large 

feeding aggregations noted near Dease Inlet and Cape Halkett, bottom-dwelling euphausiids were 

considered a likely prey source. 

Some whales observed feeding or milling in a particular location might have represented repeat sightings from 

previous days. Although repeat sightings could tend to over-emphasize the value of particular areas to the 

whale population as a whole, they would at least help identify areas of day-to-day interest to particular 

aggregations of whales. Weather permitting, our field methods tended to control against repeat sightings 

through avoidance of single areas day after day. 

D. Key Results Summary (1979-2001)

3⁄4 General sea ice severity north of Alaska during the 2001 navigation season was the 35th mildest for the 49-

year period from 1953 through 2001 (USDOC, NOAA, National Ice Center/USDOD, Navy, Naval Ice 

Center, 2002). General sea-ice coverage was considered moderate overall, with heavy sea ice 

approximately 100 nm offshore during September and with heavy sea ice all across the study area during

October. 

3⁄4 Low cloud ceilings, with occasional high sea states, permitted only 23 flights during Fall 2001. Military flight 

restrictions were imposed from 11 through 14 September. 

3⁄4 Due to the adverse environmental conditions, the annual total of 72.93 survey hours for 2001 was the 

lowest of the 15 consecutive MMS surveys (1987-2001), much lower than the mean of 127.72 hours 

(SD=36.69, n=14) for previous years (1987-2000). 

3⁄4 Also due to the adverse environmental conditions, the 29 sightings for a total of 35 individual bowhead 

whales in Fall 2001 was the lowest of the 15 consecutive MMS surveys (1987-2001), much lower than the 

401 annual mean (SD=441, n=14) for bowhead whales in previous MMS surveys (1987-2000). 

3⁄4 In 2001, the first bowheads observed were on 5 September. Sighting rates were the highest on that day 

(2.55 SPUE) as was the daily relative abundance (2.78 WPUE). The midpoint (median) of the total 

whales observed occurred on 7 September. The last sighting of a bowhead was made on 2 October. 

3⁄4 In 2001, the axis of bowhead whale sightings in the East Region (33.9 km) and the West Region (42.4 km) 

were within the 25th – 75th quartile ranges for all years (1982-2001). 

42
3⁄4 Greater relative occurrence of feeding and/or milling behaviors of bowhead whales was observed on 

transect in six of the 20 years (1984, 1989, 1997, 1998, 1999 and 2000) near the mouth of Dease Inlet, 

Alaska. Greater relative occurrence of feeding and/or milling behaviors of bowheads was observed on 

transect in four of those years (1989, 1997, 1998 and 1999) near Cape Halkett, Alaska. There were nine 

years when feeding and/or milling behaviors were noted on transect but not near Dease Inlet or Cape 

Halkett (1982, 1983, 1985, 1986, 1988, 1990, 1993, 1995, and 1996). In five other years (1987, 1991, 

1992, 1994, and 2001), neither feeding nor milling behaviors were observed on transect anywhere in the 

study area. 

3⁄4 Other results of the present study were generally within the range of result values from previous MMSfunded endangered-whale monitoring conducted during September and October (1979-2000) in the 

Beaufort Sea using similar survey methods (Ljungblad et al., 1987; Moore and Clarke, 1992; Treacy, 

1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 2000, and 2002). 

43
V. DISCUSSION 

A. Management Use of Real-Time Field Information

The MMS issues various types of permits to industry for gas and oil exploration, including vessel geophysical 

permits for on-water exploration using an array of deep-seismic airguns; vessel geological-geophysical permits 

for shallow-seismic exploration using an airgun; on-ice geophysical permits using VIBROSEIS technology; 

both vessel and on-ice geological permits for obtaining core samples; and permits to drill for gas and oil. 

During the year 2001, there were no winter or summer seismic programs in Federal waters in Alaska due 

to environmental restrictions imposed on seismic operators. The requirements for monitoring and scientific 

studies have, in some cases, doubled the cost of the seismic program. In general, to prevent potential 

operational effects on subsistence whaling, any geophysical-vessel explorations permitted during the fall 

follow stringent restrictions—including a provision to stop seismic operations when whales are visible from 

the vessel—as the bowhead whale migration progresses through the area of operations. For any 

explorations that occur during the fall, daily summaries of survey information are transferred from the field 

to Anchorage for use by MMS Resource Evaluation and by NMFS in implementing area-wide permit 

restrictions on high-energy seismic operations during the whale migration. 

The North American Natural Gas Pipeline Group (Anchorage, Alaska) conducted an independent, nearshore, 

pipeline-route and shallow-hazards survey in the Alaskan Beaufort Sea from Prudhoe Bay to the Canadian 

border from 24 July through 16 September 2001. The work, conducted with a NMFS Incidental Harassment 

Authorization, was within a single 550-m corridor between the 20-foot and 60-foot isobaths. 

Development drilling occurred at Northstar throughout 2001, except during the open-water season when 

drilling was shutdown while additional facilities were installed on the island. Development drilling is not 

allowed to penetrate into the Northstar reservoir except when there is solid ice around Northstar Island. 

During the open-water and broken ice periods, development drilling is completed to the intermediate casing 

point and the wells are re-entered and drilling completed to the production interval once solid ice develops. 

During the 2001 open-water season, the production modules and other facilities for Northstar were sea-lifted 

from Anchorage and installed on the island. In late October 2001, production commenced from the Northstar 

Project. Production reached the facility capacity in early 2002. Development drilling is continuing at Northstar 

with the same restriction addressed above. In general, during any fall drilling operations, daily summaries of 

field information from this survey, and other arctic surveys being conducted concurrently, are transferred by 

the MMS Team Leader to MMS Field Operations in Anchorage. The MMS and NMFS review daily reports to 

determine the distribution patterns of bowheads in the vicinity of oil-and-gas-industry activities and the timing 

of the bowhead whale migration, especially the “end of the migration” past any drill sites. 

The sighting data are typically used by area management groups to monitor the progress of the overall fall 

migration of bowhead whales across the Alaskan Beaufort Sea and to determine the position of their overall 

migratory corridor relative to shore. The data are also provided to other MMS studies and to industrysponsored site-specific studies investigating the potential effects of industry activity on marine mammals. 

Project ice and weather data were also transmitted daily to the National/Naval Ice Center and National 

Weather Service for use in ground-truthing satellite imagery.

B. Management Use of Interannual Monitoring

The MMS bowhead whale monitoring began in 1979 and has continued every year up to the present. While 

some aspects of this study have been updated from time to time, the data recorded have remained remarkably 

parallel (especially data from 1982-2001), thus permitting many one-to-one comparisons between years. Such 

continuous, long-term, wide-area, aerial monitoring of a large whale migration is indeed unique. 

In addition to the use of real-time information by both MMS and NMFS when documenting the progress of 

endangered bowhead whales past offshore drilling and seismic exploration operations (see Section VI.A. 

above), the project has been helpful to managers in other ways. Some notable examples are: 

45
3⁄4 providing raw data to all parties (MMS, Western Geophysical, NMFS, ARCO Alaska, Inc., and Alaska 

Eskimo Whaling Commission (AEWC) at an Oil/Whalers Agreement Post Season Meeting on 18 December 

1990 to determine whether the Fall 1990 bowhead migration had been temporarily blocked due to seismic 

exploration activities; 

3⁄4 providing all parties with annual reports from which data were subsequently cited in a declaration to a 

lawsuit in 1993 (AEWC et al. vs. Dr. Nancy Foster et al., Civil Action No. 93-1629 HHG) on the effects of 

Kuvlum drilling and seismic exploration operations on the bowhead migration corridor; 

3⁄4 providing upstream, offshore, and downstream sighting-and-effort data in order to enhance sample sizes of 

many site-specific studies looking at the potential effects of oil-industry activity on bowhead whale 

migrations; 

3⁄4 documenting geographic areas, especially migration corridors and feeding areas, used annually by 

bowhead whales. Such data from previous surveys continue to be used by MMS in writing Environmental 

Impact Statements and Environmental Assessments and in interpreting the results of site-specific studies. 

3⁄4 performing an analysis of the distances from shore to bowhead sightings relative to general sea ice 

severity. 

The BWASP was cited in the MMS Annual Report 1999, “What does it take to best manage America’s mineral 

resources?”, as an example of how our agency manages the OCS in the Beaufort Sea; 

The NMFS Administrator, Alaska Region, (letter dated 22 December 1998) commended MMS information 

support to NMFS: “The BWASP has provided a critical element in our ability to evaluate the effects of 

development in the Beaufort Sea on the bowhead whale. Additionally, the Minerals Management Service has 

demonstrated the flexibility and willingness to allow this program to compliment and extend project-specific 

monitoring required for authorizations under the Marine Mammal Protection Act (Incidental Harassment 

Authorizations). The combined information of these efforts has greatly extended our knowledge and facilitated

conflict avoidance agreements. These agreements have allowed oil and gas activities to go forward while 

minimizing interference with traditional Native subsistence hunting. We have found BWASP statistical 

analysis and data presentation to be very useful in assessing potential impacts within the Beaufort Sea.” 

C. Conclusions

We saw no indications that the migration was “stopped” in Fall 2001, including areas near the Northstar 

production site. 

Oil-industry studies, pooling our data with their own site-specific data, have detected localized deflections on 

the order of 10 to 20 km by bowhead whales in the immediate vicinity of certain types of active seismic 

exploration (USDOI, MMS, 1997). Since preliminary power analysis of the ANOVA for distance of bowhead 

whales from shore (α=0.05, β≤0.01) showed minimum detectable differences of 7.8 km in the East Region and 

9.7 km in the West (Treacy, 1998), we should be able to detect major region-wide 10- to 20-km shifts between 

years that may have derived from localized deflections. 

East Region bowheads in 1983 migrated significantly (p<0.05) farther offshore than in any other year except 

1989. The data also showed that whales in 1989 and 1991 were significantly farther offshore, and in 1997, 

and 1998 were significantly nearer to shore, than for most (>10) other years. West Region bowheads in 2000 

migrated significantly (p<0.05) nearer to shore than for most (>10) other years. The pattern of median 

distances of bowhead whales from shore in the East and West Regions (1982-1999) was shown in Treacy 

(2000: Fig. 39). 

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 (other than sea ice) 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. Both Kaktovik and Nuiqsut communities conduct subsistence whale hunts 

each year in the central Alaskan Beaufort Sea, where the distance offshore to conduct this important 

subsistence activity can be crucial to their safety and hunting success. To the extent villagers from Barrow 

46
utilize the area east of 155°W. longitude to hunt whales, distances from shore to the main migration corridor 

would likewise be negatively affected in heavier ice years. 

Greater relative occurrence of feeding and/or milling behaviors of bowhead whales was observed on transect

in six of the 20 years (1984, 1989, 1997, 1998, 1999 and 2000) near the mouth of Dease Inlet, Alaska. Similar 

relative occurrence of feeding and/or milling behaviors of bowheads was observed on transect in four of those 

years (1989, 1997, 1998 and 1999) near Cape Halkett, Alaska. There were nine years when feeding and/or 

milling behaviors were noted on transect but not near Dease Inlet or Cape Halkett (1982, 1983, 1985, 1986, 

1988, 1990, 1993, 1995, and 1996). In five other years (1987, 1991, 1992, 1994, and 2001), neither feeding 

nor milling behaviors were observed on transect anywhere in the study area. 

D. Field Coordination and Other Information Support

During the field season, we coordinated with AEWC, Barrow, Alaska; Whalers Communication Center, 

Deadhorse, Alaska; NMFS, Anchorage, Alaska; and NSB, Department of Wildlife Management, Barrow, 

Alaska. 

Selected BWASP information-support activities during calendar year 2001 included: 

3⁄4 providing data to and coordinating with scientists and subsistence whalers in support of the MMS study 

“Bowhead Whale Feeding in the Eastern Alaskan Beaufort Sea: Update of Scientific and Traditional 

Information”; 

3⁄4 presenting information on flight-following technologies to the Alaska Interagency Aviation Working Group, 

Anchorage, Alaska (16 January); 

3⁄4 contributing data and reviewing visual-display materials for a poster “Visualizing Cetacean Habitats 

Offshore Northern Alaska”, National Science Foundation’s Arctic GIS Workshop, Seattle, Washington, 

(22-24 Jan); 

3⁄4 contributing Fall-2000 BWASP data to help “air-truth” BP Exploration (Alaska)’s passive acoustics study

monitoring site-specific effects of Northstar operations on bowhead whales; 

3⁄4 presenting “Minerals Management Service Aerial Monitoring of Fall 1998-1999 Bowhead Whale Migrations” 

at the Alaska Region Information Transfer Meeting, Anchorage, Alaska; 

3⁄4 participating in annual interagency evaluations (with NMFS, NSB, AEWC) on BP Exploration (Alaska)’s and 

WesternGeco’s site-specific planned and reported monitoring of marine mammals near seismic and 

Northstar pre-production operations, 5-7 June 2001, National Marine Mammal Laboratory Seattle, 

Washington; 

3⁄4 providing a PDF version of the report “Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 

1998-1999” to Environmental Studies Program Information System (http://mmspub.mms.gov:81/espis); 

3⁄4 providing assistance to Mr. Brian Benson, Civil Engineer, Watson Company Inc. in assessing sea-ice 

conditions east of Kaktovik, Alaska, in support of a surface-vessel shallow-hazards survey along the 

proposed northern gas-pipeline route; 

3⁄4 providing requested maps of bowhead whale distribution to various MMS EIS writers; 

3⁄4 permitting BWASP data to be used in a site-specific analysis estimating potential takes of whales by the 

construction and operation of the planned Liberty Island project; 

3⁄4 presenting a poster titled “Bowhead Whales (Balaena mysticetus) Occur Farther Offshore in Heavy-Ice 

Years During Fall Migrations Across the Central Alaskan Beaufort Sea” at the 14th Biennial Conference on 

Marine Mammal Biology. 

47
VI. LITERATURE CITED

Aagaard, K. 1984. The Beaufort Undercurrent. In: The Alaskan Beaufort Sea: Ecosystems and Environment. 

 P.W. Barnes, D.M. Schell, and E. Reimnitz (eds.). Academic Press., pp. 47-71. 

Brower, W.A., R.G. Baldwin, C.N. Williams, J.L. Wise, and L.D. Leslie. 1988. Climatic Atlas of the Outer 

Continental Shelf Waters and Coastal Regions of Alaska, Volume III. OCS Study MMS 87-0013. USDOI, 

MMS, Alaska OCS Region, 524 pp. 

Chapman, C.F. 1971. Piloting, Seamanship and Small Boat Handling. New York, NY: Hearst Books, 640 pp. 

Cochran, W.G. 1963. Sampling Techniques. New York, NY: J. Wiley, 413 pp. 

Endangered Species Act of 1973, as amended. 16 USC 1531-1543. 

Houghton, J.P., D.A. Segar, and J.E. Zeh. 1984. Beaufort Sea Monitoring Program. In: Proceedings of a 

Workshop (September 1983) and Sampling Design Recommendations. Prepared by Dames and Moore, 

Seattle, WA, for the OCS Environmental Assessment Program, Juneau, AK, 111 pp. 

Johnson, M.A., A.Y. Proshutinsky, and I.V. Polakov. 1999. Atmospheric Patterns Forcing Two Regimes of 

Arctic Circulation: A Return to Anticyclonic Conditions? Geophys. Res. Lett 26: 1621-1624. 

LaBelle, J.C., J.L. Wise, R.P. Voelker, R.H. Schulze, and G.M. Wohl. 1983. Alaska Marine Ice Atlas. Arctic 

Environmental Information and Data Center, University of Alaska, Anchorage, AK, 302 pp. 

Landino, S.W., S.D. Treacy, S.A. Zerwick, and J.B. Dunlap. 1994. A Large Aggregation of Bowhead Whales 

(Balaena mysticetus) Feeding near Point Barrow, Alaska, in Late October 1992. Arctic 47 (3): 232-235. 

LGL Ecological Research Associates, Inc. 1987. Importance of the Eastern Alaskan Beaufort Sea to Feeding 

Bowhead Whales, 1985-86, W.J. Richardson, ed. OCS Study MMS 87-0037. Prepared for USDOI, MMS, 

Alaska OCS Region. 

Ljungblad, D.K., S.E. Moore, and J.T. Clarke. 1986. Assessment of Bowhead Whale (Balaena mysticetus) 

Feeding Patterns in the Alaskan Beaufort and Northeastern Chukchi Seas via Aerial Surveys, Fall 1979-84.

 Rep. Int. Whal. Commn. 36 (SC/37/PS1): 265-272. 

Ljungblad, D.K., S.E. Moore, J.T. Clarke, and J.C. Bennett. 1987. Distribution, Abundance, Behavior and 

Bioacoustics of Endangered Whales in the Alaskan Beaufort and Eastern Chukchi Seas, 1979-86. OCS 

Study MMS 87-0039. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 391 pp. 

Marine Mammal Protection Act of 1972. 16 USC 1361-1407. 

Moore, S.E. 2000. Variability of Cetacean Distribution and Habitat Selection in the Alaskan Arctic, Autumn 

1982-91. Arctic 53 (4): 448-460. 

Moore, S.E. and J.T. Clarke. 1992. Distribution, Abundance and Behavior of Endangered Whales in the 

Alaskan Chukchi and Western Beaufort Seas, 1991: With a Review 1982-91. OCS Study MMS 92-0029. 

Anchorage, AK: USDOI, MMS, Alaska OCS Region, 211 pp. 

Moore, S.E. and D.P. DeMaster. 1997. Cetacean Habitats in the Alaskan Arctic. J. NW Atlantic Fish. Sci. 22:

55-69. 

National Environmental Policy Act of 1969. 42 USC 4321-4347. 

Norton, D. and G. Weller. 1984. The Beaufort Sea: Background, History, and Perspective. In: The Alaskan 

Beaufort Sea, P. Barnes, D. Schell, and E. Reimnitz, eds. Orlando, FL: Academic Press, Inc., 466 pp. 

49
Outer Continental Shelf Lands Act of 1953, as amended in 1978. 43 USC 1331-1356 and 1801-1866. 

Proshutinsky and Johnson. 1997. Two Circulation Regimes of the Wind-driven Arctic Ocean. Journal of 

Geophysical Research 102(C6):12493-12514. 

Rice, D.W. 1998. Marine Mammals of the World: Systematics and Distribution. Special Publication Number 

4. The Society for Marine Mammalogy. 231 pp. 

Treacy, S.D. 1988. Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 1987. OCS Study MMS 

88-0030. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 141 pp. 

Treacy, S.D. 1989. Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 1988. OCS Study MMS 

89-0033. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 101 pp. 

Treacy, S.D. 1990. Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 1989. OCS Study MMS 

90-0047. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 104 pp. 

Treacy, S.D. 1991. Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 1990. OCS Study MMS 

91-0055. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 107 pp. 

Treacy, S.D. 1992. Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 1991. OCS Study MMS 

92-0017. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 92 pp. 

Treacy, S.D. 1993. Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 1992. OCS Study MMS 

93-0023. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 135 pp. 

Treacy, S.D. 1994. Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 1993. OCS Study MMS 

94-0032. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 132 pp. 

Treacy, S.D. 1995. Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 1994. OCS Study MMS 

95-0033. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 116 pp. 

Treacy, S.D. 1996. Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 1995. OCS Study MMS 

96-0006. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 120 pp. 

Treacy, S.D. 1997. Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 1996. OCS Study MMS 

97-0016. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 115 pp. 

Treacy, S.D. 1998. Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 1997. OCS Study MMS 

98-0059. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 143 pp. 

Treacy, S.D. 2000. Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 1998-1999. OCS Study 

MMS 2000-066. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 135 pp. 

Treacy, S.D. 2001. Bowhead Whales (Balaena mysticetus) Occur Farther Offshore in Heavy-Ice Years 

during Fall Migrations across the Central Alaskan Beaufort Sea. Abstract In: 14th Biennial Conference on 

the Biology of Marine Mammals, Abstracts (28 Nov. – 3 Dec 2001; Vancouver B.C. Canada). p. 217. 

Treacy, S.D. 2002. Aerial Surveys of Endangered Whales in the Beaufort Sea, Fall 2000. OCS Study MMS 

2002-014. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 111 pp. 

USDOC, NOAA, NMFS. 1982. Endangered Species Act, Section 7 Consultation - Biological Opinion, Oil and 

Gas Lease Sale 71 (Diapir Field). 19 May 1982. Washington, D.C. 

50
USDOC, NOAA, NMFS. 1983. Endangered Species Act, Section 7 Consultation - Biological Opinion, Oil and 

Gas Leasing and Exploration-Diapir Field Lease Offering (Sale 87). 19 December 1983. Washington, D.C.

USDOC, NOAA, NMFS. 1987. Endangered Species Act, Section 7 Consultation - Biological Opinion, Oil and 

Gas Leasing and Exploration - Beaufort Sea Sale 97. 20 May 1987. Washington, D.C. 

USDOC, NOAA, NMFS. 1988. Endangered Species Act, Section 7 Consultation - Biological Opinion, Oil and 

Gas Leasing and Exploration - Arctic Region. 23 November 1988. Washington, D.C. 

USDOC, NOAA, National Ice Center/USDOD, Navy, Naval Ice Center. 2002. Seasonal Outlook, Sea Ice 

Conditions for the Alaskan North Coast, Summer 2002. Washington, D.C., 4 pp. 

USDOD, Navy, Naval Hydrographic Office. 1956. Aerial Ice Reconnaissance and Functional Glossary of Ice

Terminology. Hydrographic Office Publication No. 609, 14 pp. 

USDOI, MMS. 1979. State of Alaska, Department of Natural Resources; Federal/State Joint Beaufort Sea Oil 

and Gas Lease Sale BF, November 7, 1979 (44 FR 64752). 

USDOI, MMS. 1982. Memorandum from Director, BLM, to Secretary of the Interior, dated 30 April 1982; 

subject: Decision on the Modification of the Seasonal Drilling Restriction. 

USDOI, MMS. 1984. Outer Continental Shelf, Diapir Field, Oil and Gas Lease Sale 87, July 23, 1984 (49 FR 

29726). 

USDOI, MMS. 1988. Outer Continental Shelf, Beaufort Sea, Oil and Gas Lease Sale 97, February 12, 1988 

(53 FR 4356). 

USDOI, MMS. 1991. Outer Continental Shelf Beaufort Sea Oil and Gas Lease Sale 124, May 24, 1991 (56 

FR 23966). 

USDOI, MMS. 1996. Outer Continental Shelf Beaufort Sea Oil and Gas Lease Sale 144, August 16, 1996 (61 

FR 42682). 

USDOI, MMS. 1997. Arctic Seismic Synthesis and Mitigating measures Workshop. OCS Study MMS 97-

0014. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 71 pp. plus appendices. 

USDOI, MMS. 1998. Alaska Outer Continental Shelf, Beaufort Sea Planning Area Oil and Gas Lease Sale 

170 OCS EIS/EA MMS 98-0007. 

USDOI, MMS. 2001. Project Management Plan, MMS Fall 2001 Bowhead Whale Aerial Survey Project, 

August 2001. Anchorage, AK: USDOI, MMS, Alaska OCS Region, 14 pp. 

Zar, S.H. 1984. Biostatistical Analysis. Englewood Cliffs, NJ: Prentice Hall, Inc., 620 pp. 

51
APPENDIX A

FALL-2001 ICE-CONCENTRATION MAPS FOR THE ALASKAN BEAUFORT SEA 

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APPENDIX B

FALL-2001 BOWHEAD WHALE SIGHTING DATA 

65
Table B-1 

Selected Sighting Data for Bowhead Whales Observed, Fall 2001 

Flight 

No. Day

Total 

Whales 

No. of 

Calves Latitude Longitude Behavior 

Compass 

Heading 

Ice 

(%) 

Wind

Force

3 5 Sep 1 0 69o53.6' 140o21.5' rest 240° 0 2

3 5 Sep 1 0 69o58.2' 140o20.7' breach 275° 0 2

3 5 Sep 1 0 70o01.2' 140o50.1' swim 240° 0 3

3 5 Sep 1 0 70o00.4' 140°49.3' swim 250° 0 3

3 5 Sep 2 1 69o57.3' 140°50.8' cow-calf 250° 0 3

3 5 Sep 1 0 69°57.0' 140°50.9' swim 245° 0 3

3 5 Sep 1 0 70°01.7' 141°17.8' swim 270° 0 3

3 5 Sep 1 0 70°06.9' 141°16.9' breach 0° 0 4

3 5 Sep 1 0 70°10.1' 141°21.3' swim 240° 0 4

3 5 Sep 1 0 70°17.6' 142°42.9' swim 240° 0 6

3 5 Sep 1 0 70°11.3' 142°36.5' swim 240° 0 6

4 6 Sep 2 0 69°59.7' 141°46.0' rest 30° 0 2

4 6 Sep 1 0 70°27.1' 145°34.8' swim 270° 0 2

5 7 Sep 1 0 70°26.8' 144°24.4' swim 320° 0 2

5 7 Sep 1 0 70°26.9' 144°22.4' swim 300° 0 2

5 7 Sep 1 0 70°27.3' 144°14.5' swim 270° 0 2

5 7 Sep 1 0 70°27.8' 144°06.7' swim 240° 0 2

5 7 Sep 1 0 70°28.4' 143°58.1' swim 240° 0 2

5 7 Sep 2 0 70°28.6' 143°55.2' swim 270° 0 2

5 7 Sep 3 0 70°27.0' 144°27.0' swim 210° 1 2

8 10 Sep 1 0 70°54.1' 152°16.0' swim 245° 1 3

8 10 Sep 1 0 70°55.1' 152°10.1' swim 250° 10 2

8 10 Sep 1 0 71°08.0' 148°40.2' rest 245° 20 1

8 10 Sep 1 0 70°27.9' 147°13.7' rest 250° 5 1

16 2 Oct 1 0 70°18.3' 145°02.0' swim 245° 0 4

16 2 Oct 1 0 70°17.5' 144°48.7' swim 270° 0 3

16 2 Oct 1 0 70°09.9' 143°45.7' swim 160° 0 2

16 2 Oct 2 1 70°14.0' 144°25.9' swim 260° 0 2

16 2 Oct 1 0 70°27.1' 147°07.4' swim 30° 0 5

1

 Not recorded. 

2

 Possible repeat sighting. 

3

 Definite repeat sighting (excluded from analyses). 

4

 Dead whale (excluded from analyses). 

67
APPENDIX C

FALL-2001 DAILY FLIGHT SUMMARIES 

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APPENDIX D

FALL FEEDING AND MILLING WHALES PER UNIT EFFORT (1982-2000) 

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113
APPENDIX E

GLOSSARY OF ABBREVIATIONS, ACRONYMS, AND INITIALISMS 

115
GLOSSARY OF ABBREVIATIONS, ACRONYMS, AND INITIALISMS

AEWC Alaska Eskimo Whaling Commission 

ANOVA analysis of variance 

BLM Bureau of Land Management 

BWASP Bowhead Whale Aerial Survey Project 

CI confidence interval 

e.g. for example 

ESA Endangered Species Act 

FR Federal Register 

GPS Global Positioning System 

hr hour 

HSD “honestly significant difference” (Tukey statistical test) 

i.e. that is 

k number of samples 

km kilometer 

m meter 

MMS Minerals Management Service 

n sample size 

NOAA National Oceanic and Atmospheric Administration 

NOS Notice of Sale 

NMFS National Marine Fisheries Service 

nm nautical mile 

NSB North Slope Borough 

OAS Office of Aircraft Services 

OCS Outer Continental Shelf 

OCSLA Outer Continental Shelf Lands Act 

p probability

SD standard deviation 

SPUE sightings per unit effort (sighting rate) 

trSI transect sightings 

USC U.S. Code 

USDOC U.S. Department of Commerce 

USDOD U.S. Department of Defense 

USDOI U.S. Department of the Interior 

WPUE whales per unit effort (index of relative abundance or occurrence) 

117
The Department of the Interior Mission

As the Nation's principal conservation agency, the Department of the Interior has responsibility for 

most of our nationally owned public lands and natural resources. This includes fostering sound use 

of our land and water resources; protecting our fish, wildlife, and biological diversity; preserving the 

environmental and cultural values of our national parks and historical places; and providing for the 

enjoyment of life through outdoor recreation. The Department assesses our energy and mineral 

resources and works to ensure that their development is in the best interests of all our people by 

encouraging stewardship and citizen participation in their care. The Department also has a major 

responsibility for American Indian reservation communities and for people who live in island 

territories under U.S. administration. 

The Minerals Management Service Mission 

As a bureau of the Department of the Interior, the Minerals Management Service's (MMS) primary 

responsibilities are to manage the mineral resources located on the Nation's Outer Continental 

Shelf (OCS), collect revenue from the Federal OCS and onshore Federal and Indian lands, and 

distribute those revenues.

Moreover, in working to meet its responsibilities, the Offshore Minerals Management Program

administers the OCS competitive leasing program and oversees the safe and environmentally 

sound exploration and production of our Nation's offshore natural gas, oil and other mineral 

resources. The MMS Royalty Management Program meets its responsibilities by ensuring the 

efficient, timely and accurate collection and disbursement of revenue from mineral leasing and 

production due to Indian tribes and allottees, States and the U.S. Treasury. 

The MMS strives to fulfill its responsibilities through the general guiding principles of: (1) being

responsive to the public's concerns and interests by maintaining a dialogue with all potentially 

affected parties and (2) carrying out its programs with an emphasis on working to enhance the 

quality of life for all Americans by lending MMS assistance and expertise to economic development 

and environmental protection.