U.S. Department of the Interior

Bureau of Ocean Energy Management 

Gulf of Mexico OCS Region 

OCS EIS/EA 

BOEM 2012-005 

Atlantic OCS 

Proposed Geological and Geophysical Activities 

Mid-Atlantic and South Atlantic Planning Areas 

Draft Programmatic Environmental Impact Statement 

Volume II: Figures, Tables, Appendices, and Keyword Index 

 
U.S. Department of the Interior 

Bureau of Ocean Energy Management 

Gulf of Mexico OCS Region 

OCS EIS/EA 

BOEM 2012-005 

Atlantic OCS 

Proposed Geological and Geophysical Activities 

Mid-Atlantic and South Atlantic Planning Areas 

Draft Programmatic Environmental Impact Statement 

Volume II: Figures, Tables, Appendices, and Keyword Index 

Author 

Bureau of Ocean Energy Management 

Gulf of Mexico OCS Region 

Prepared under 

General Services Administration Task Order No. M11PD00013 

by 

Continental Shelf Associates International Inc. 

8502 SW Kansas Avenue 

Stuart, Florida 34997 

Cover Photo (Ship) – courtesy WesternGeco 

Cover Photo (Whales) – courtesy National Oceanic and Atmospheric Administration/National Ocean Service 

Published by 

New Orleans

March 2012 

Table of Contents iii 

TABLE OF CONTENTS 

Volume I 

Page 

SUMMARY................................................................................................................................................vii 

LIST OF FIGURES ..............................................................................................................................xxxvii 

LIST OF TABLES......................................................................................................................................xli 

ACRONYMS AND ABBREVIATIONS ..................................................................................................xlv

1. INTRODUCTION ...............................................................................................................................1-3

1.1. Background..............................................................................................................................1-3

1.2. Programmatic Approach to the NEPA Process........................................................................1-4

1.3. Objectives and Scope...............................................................................................................1-5

1.3.1. Objectives..................................................................................................................1-5

1.3.2. Area of Interest..........................................................................................................1-5

1.3.3. Types of G&G Activities Analyzed ..........................................................................1-6

1.4. Purpose of and Need for the Proposed Action.........................................................................1-7

1.4.1. Background ...............................................................................................................1-7

1.4.2. Purpose and Need......................................................................................................1-8

1.5. Cooperating Agencies..............................................................................................................1-8

1.6. Regulatory Framework ............................................................................................................1-9

1.6.1. Rule Changes for Reorganization of Title 30: Bureaus of Safety and 

Environmental Enforcement and Ocean Energy Management .................................1-9

1.6.2. Outer Continental Shelf Lands Act .........................................................................1-10

1.6.3. National Environmental Policy Act ........................................................................1-11

1.6.4. Executive Order 12114, Environmental Effects Abroad of Major Federal 

Actions ....................................................................................................................1-11

1.6.5. Coastal Zone Management Act ...............................................................................1-11

1.6.6. Endangered Species Act..........................................................................................1-12

1.6.7. Marine Mammal Protection Act..............................................................................1-13

1.6.8. Magnuson-Stevens Fishery Conservation and Management Act............................1-14

1.6.9. Clean Air Act ..........................................................................................................1-14

1.6.10. Clean Water Act ......................................................................................................1-15

1.6.11. National Historic Preservation Act..........................................................................1-15

1.6.12. Migratory Bird Treaty Act ......................................................................................1-16

1.6.13. Executive Order 13547, Stewardship of the Ocean, Our Coasts, and the Great 

Lakes ................................................................................................................1-16

1.6.14. Rivers and Harbors Act ...........................................................................................1-16

1.6.15. National Marine Sanctuaries Act ............................................................................1-17

1.6.16. State Permitting .......................................................................................................1-17

1.7. Environmental Review Process .............................................................................................1-18

1.7.1. Scoping....................................................................................................................1-18

1.7.2. Draft Programmatic Environmental Impact Statement ...........................................1-19

1.7.3. Final Programmatic Environmental Impact Statement ...........................................1-19

1.7.4. Record of Decision..................................................................................................1-19

2. ALTERNATIVES INCLUDING THE PROPOSED ACTION ..........................................................2-3

2.1. Alternative A – The Proposed Action......................................................................................2-3

2.1.1. Description ................................................................................................................2-3
iv Atlantic G&G Programmatic EIS

2.1.2. Mitigation Measures..................................................................................................2-3

2.1.2.1. Time-Area Closure for North Atlantic Right Whales ..............................2-4

2.1.2.2. Seismic Airgun Survey Protocol..............................................................2-4

2.1.2.3. HRG Survey Protocol (Renewable Energy and Marine Minerals 

Sites).........................................................................................................2-6

2.1.2.4. Guidance for Vessel Strike Avoidance ....................................................2-7

2.1.2.5. Guidance for Marine Debris Awareness ..................................................2-8

2.1.2.6. Avoidance of Sensitive Seafloor Resources.............................................2-8

2.1.2.7. Guidance for Activities in or Near National Marine Sanctuaries ............2-9

2.1.2.8. Guidance for Military and NASA Coordination....................................2-10

2.1.3. Summary of Impacts ...............................................................................................2-10

2.1.3.1. Impacts on Benthic Communities (Chapter 4.2.1).................................2-11

2.1.3.2. Impacts on Marine Mammals (Chapter 4.2.2) .......................................2-11

2.1.3.3. Impacts on Sea Turtles (Chapter 4.2.3)..................................................2-16

2.1.3.4. Impacts on Marine and Coastal Birds (Chapter 4.2.4)...........................2-19

2.1.3.5. Impacts on Fish Resources and Essential Fish Habitat 

(Chapter 4.2.5) .......................................................................................2-20

2.1.3.6. Impacts on Threatened or Endangered Fish Species 

(Chapter 4.2.6) .......................................................................................2-21

2.1.3.7. Impacts on Commercial Fisheries (Chapter 4.2.7).................................2-22

2.1.3.8. Impacts on Recreational Fisheries (Chapter 4.2.8) ................................2-23

2.1.3.9. Impacts on Recreational Resources (Chapter 4.2.9) ..............................2-24

2.1.3.10. Impacts on Archaeological Resources (Chapter 4.2.10) ........................2-24

2.1.3.11. Impacts on Marine Protected Areas (Chapter 4.2.11)............................2-25

2.1.3.12. Impacts on Other Marine Uses (Chapter 4.2.12) ...................................2-26

2.1.3.13. Impacts on Human Resources and Land Use (Chapter 4.2.13)..............2-27

2.2. Alternative B – Additional Time-Area Closures and Separation of Simultaneous 

Seismic Airgun Surveys.........................................................................................................2-27

2.2.1. Description ..............................................................................................................2-27

2.2.2. Mitigation Measures................................................................................................2-27

2.2.2.1. Expanded Time-Area Closure for North Atlantic Right Whales ...........2-28

2.2.2.2. Time-Area Closure for Nesting Sea Turtles Offshore Brevard 

County, Florida ......................................................................................2-28

2.2.2.3. Separation between Simultaneous Seismic Airgun Surveys..................2-29

2.2.2.4. Seismic Airgun Survey Protocol with Required Use of Passive 

Acoustic Monitoring ..............................................................................2-29

2.2.3. Summary of Impacts ...............................................................................................2-29

2.2.3.1. Impacts on Benthic Communities (Chapter 4.3.1).................................2-30

2.2.3.2. Impacts on Marine Mammals (Chapter 4.3.2) .......................................2-30

2.2.3.3. Impacts on Sea Turtles (Chapter 4.3.3)..................................................2-31

2.2.3.4. Impacts on Marine and Coastal Birds (Chapter 4.3.4)...........................2-32

2.2.3.5. Impacts on Fish Resources and Essential Fish Habitat 

(Chapter 4.3.5) .......................................................................................2-33

2.2.3.6. Impacts on Threatened or Endangered Fish Species 

(Chapter 4.3.6) .......................................................................................2-33

2.2.3.7. Impacts on Commercial Fisheries (Chapter 4.3.7).................................2-34

2.2.3.8. Impacts on Recreational Fisheries (Chapter 4.3.8) ................................2-34

2.2.3.9. Impacts on Recreational Resources (Chapter 4.3.9) ..............................2-35

2.2.3.10. Impacts on Archaeological Resources (Chapter 4.3.10) ........................2-35

2.2.3.11. Impacts on Marine Protected Areas (Chapter 4.3.11)............................2-36

2.2.3.12. Impacts on Other Marine Uses (Chapter 4.3.12) ...................................2-36

2.2.3.13. Impacts on Human Resources and Land Use (Chapter 4.3.13)..............2-37

2.3. Alternative C – No Action for Oil and Gas, Status Quo for Renewable Energy and 

Marine Mineral G&G Activity ..............................................................................................2-37

2.3.1. Description ..............................................................................................................2-37

2.3.2. Mitigation Measures................................................................................................2-38
Table of Contents v 

2.3.3. Summary of Impacts ...............................................................................................2-38

2.3.3.1. Impacts on Benthic Communities (Chapter 4.4.1).................................2-38

2.3.3.2. Impacts on Marine Mammals (Chapter 4.4.2) .......................................2-39

2.3.3.3. Impacts on Sea Turtles (Chapter 4.4.3)..................................................2-40

2.3.3.4. Impacts on Marine and Coastal Birds (Chapter 4.4.4)...........................2-41

2.3.3.5. Impacts on Fish Resources and Essential Fish Habitat 

(Chapter 4.4.5) .......................................................................................2-41

2.3.3.6. Impacts on Threatened or Endangered Fish Species 

(Chapter 4.4.6) .......................................................................................2-41

2.3.3.7. Impacts on Commercial Fisheries (Chapter 4.4.7).................................2-42

2.3.3.8. Impacts on Recreational Fisheries (Chapter 4.4.8) ................................2-42

2.3.3.9. Impacts on Recreational Resources (Chapter 4.4.9) ..............................2-43

2.3.3.10. Impacts on Archaeological Resources (Chapter 4.4.10) ........................2-43

2.3.3.11. Impacts on Marine Protected Areas (Chapter 4.4.11)............................2-43

2.3.3.12. Impacts on Other Marine Uses (Chapter 4.4.12) ...................................2-44

2.3.3.13. Impacts on Human Resources and Land Use (Chapter 4.4.13)..............2-44

2.4. Issues......................................................................................................................................2-45

2.4.1. Issues to be Analyzed..............................................................................................2-45

2.4.2. Issues Considered but Not Analyzed.......................................................................2-46

2.5. Alternatives Considered but Not Analyzed............................................................................2-46

2.5.1. Limit Permitting G&G Activities to Renewable Energy and Marine Minerals ......2-46

2.5.2. Expand Permitted G&G Activities into the North Atlantic Planning Area.............2-47

2.5.3. Reprocess Existing G&G Data................................................................................2-47

2.5.4. Delay the Permitting Process ..................................................................................2-48

2.5.5. Consolidate and Coordinate Surveys ......................................................................2-48

2.5.6. Require Non-Airgun Acoustic Sources...................................................................2-49

2.5.6.1. Marine Vibrators (Vibroseis) .................................................................2-49

2.5.6.2. Low-Frequency Acoustic Source (patented) (LACS)............................2-51

2.5.6.3. Deep-Towed Acoustics/Geophysics System (DTAGS).........................2-51

2.5.6.4. Low-Frequency Passive Seismic Methods for Exploration ...................2-52

2.5.6.5. Low-Impact Seismic Array (LISA) .......................................................2-53

2.5.6.6. Fiber Optic Receivers.............................................................................2-53

2.5.6.7. Airgun Modifications to Lessen Impacts ...............................................2-53

2.5.6.8. Evaluation ..............................................................................................2-54

2.6. Comparison of Impacts by Alternative ..................................................................................2-54

2.7. Preferred Alternative..............................................................................................................2-56

3. G&G ACTIVITIES AND PROPOSED ACTION SCENARIO..........................................................3-3

3.1. Introduction..............................................................................................................................3-3

3.2. Oil and Gas G&G Surveys.......................................................................................................3-3

3.2.1. Background and Jurisdiction.....................................................................................3-4

3.2.2. Types of Surveys.......................................................................................................3-5

3.2.2.1. Deep Penetration Seismic Surveys...........................................................3-6

3.2.2.2. High-Resolution Geophysical Surveys ....................................................3-9

3.2.2.3. Electromagnetic Surveys........................................................................3-10

3.2.2.4. Deep Stratigraphic and Shallow Test Drilling .......................................3-10

3.2.2.5. Bottom Sampling ...................................................................................3-11

3.2.2.6. Passive Remote-Sensing Surveys ..........................................................3-11

3.2.3. Proposed Action Scenario .......................................................................................3-13

3.2.3.1. Areas Considered for Oil and Gas Exploration......................................3-13

3.2.3.2. Projected Activity Levels.......................................................................3-13
vi Atlantic G&G Programmatic EIS

3.3. Renewable Energy G&G Surveys for Site Assessment and Characterization.......................3-13

3.3.1. Background and Jurisdiction...................................................................................3-13

3.3.2. Types of Surveys.....................................................................................................3-15

3.3.2.1. High-Resolution Geophysical Surveys ..................................................3-15

3.3.2.2. Geotechnical Surveys.............................................................................3-17

3.3.2.3. Bottom-Founded Monitoring Buoy Deployments .................................3-18

3.3.3. Proposed Action Scenario .......................................................................................3-19

3.3.3.1. Areas Considered for Renewable Energy Projects ................................3-19

3.3.3.2. Projected Activity Levels.......................................................................3-20

3.4. Marine Minerals G&G Surveys .............................................................................................3-20

3.4.1. Background and Jurisdiction...................................................................................3-21

3.4.2. Types of Surveys.....................................................................................................3-22

3.4.2.1. High Resolution Geophysical Surveys...................................................3-22

3.4.2.2. Geotechnical Surveys.............................................................................3-23

3.4.3. Proposed Action Scenario .......................................................................................3-23

3.4.3.1. Areas Considered for Marine Minerals Projects ....................................3-23

3.4.3.2. Projected Activity Levels.......................................................................3-24

3.5. Proposed Action Scenario Summary and Impact-Producing Factors ....................................3-25

3.5.1. Impact-Producing Factors for Routine Activities....................................................3-25

3.5.1.1. Active Acoustic Sound Sources .............................................................3-25

3.5.1.2. Vessel and Equipment Noise .................................................................3-27

3.5.1.3. Vessel Traffic.........................................................................................3-28

3.5.1.4. Aircraft Traffic and Noise......................................................................3-29

3.5.1.5. Vessel Exclusion Zones .........................................................................3-30

3.5.1.6. Vessel Wastes ........................................................................................3-31

3.5.1.7. Trash and Debris ....................................................................................3-31

3.5.1.8. Seafloor Disturbance..............................................................................3-32

3.5.1.9. Drilling Discharges ................................................................................3-34

3.5.1.10. Onshore Support Activities....................................................................3-35

3.5.2. Impact-Producing Factors for Accidental Events....................................................3-35

3.5.2.1. Accidental Fuel Spills ............................................................................3-35

3.6. Cumulative Activities Scenario .............................................................................................3-36

3.6.1. Oil and Gas Exploration and Development.............................................................3-36

3.6.2. Renewable Energy Development ............................................................................3-37

3.6.3. Marine Minerals Use...............................................................................................3-38

3.6.4. Geosequestration .....................................................................................................3-39

3.6.5. Liquefied Natural Gas Import Terminals ................................................................3-39

3.6.6. Commercial and Recreational Fishing ....................................................................3-40

3.6.7. Military Range Complexes and Civilian Space Program Use.................................3-40

3.6.8. Shipping and Marine Transportation.......................................................................3-41

3.6.9. Dredged Material Disposal......................................................................................3-41

3.6.10. Climate Change .......................................................................................................3-42

3.6.11. Cumulative Noise in the Sea ...................................................................................3-43

4. DESCRIPTION OF THE AFFECTED RESOURCES AND IMPACT ANALYSIS .........................4-3

4.1. Introduction..............................................................................................................................4-3

4.1.1. Preliminary Screening of Activities and Affected Resources ...................................4-3

4.1.1.1. Activity Screening....................................................................................4-4

4.1.1.2. Resource Screening..................................................................................4-4

4.1.2. Impact Levels and Impact Significance Criteria .......................................................4-5

4.1.3. Impact-Producing Factors .........................................................................................4-6

4.1.4. Other Considerations.................................................................................................4-6

4.1.4.1. Analysis and Incomplete or Unavailable Information .............................4-6

4.1.4.2. Space-Use Conflicts.................................................................................4-6
Table of Contents vii 

4.2. Alternative A – The Proposed Action......................................................................................4-8

4.2.1. Benthic Communities................................................................................................4-9

4.2.1.1. Description of the Affected Environment ................................................4-9

4.2.1.2. Impacts of Routine Events .....................................................................4-15

4.2.1.3. Impacts of Accidental Fuel Spills ..........................................................4-21

4.2.1.4. Cumulative Impacts ...............................................................................4-21

4.2.2. Marine Mammals ....................................................................................................4-25

4.2.2.1. Description of the Affected Environment ..............................................4-25

4.2.2.2. Impacts of Routine Events .....................................................................4-43

4.2.2.3. Impacts of Accidental Fuel Spills ..........................................................4-61

4.2.2.4. Cumulative Impacts ...............................................................................4-62

4.2.3. Sea Turtles...............................................................................................................4-65

4.2.3.1. Description of the Affected Environment ..............................................4-65

4.2.3.2. Impacts of Routine Events .....................................................................4-77

4.2.3.3. Impacts of Accidental Fuel Spills ..........................................................4-85

4.2.3.4. Cumulative Impacts ...............................................................................4-85

4.2.4. Marine and Coastal Birds........................................................................................4-88

4.2.4.1. Description of the Affected Environment ..............................................4-88

4.2.4.2. Impacts of Routine Events .....................................................................4-93

4.2.4.3. Impacts of Accidental Fuel Spills ........................................................4-101

4.2.4.4. Cumulative Impacts .............................................................................4-102

4.2.5. Fisheries Resources and Essential Fish Habitat ....................................................4-106

4.2.5.1. Description of the Affected Environment ............................................4-106

4.2.5.2. Impacts of Routine Events ...................................................................4-118

4.2.5.3. Impacts of Accidental Fuel Spills ........................................................4-122

4.2.5.4. Cumulative Impacts .............................................................................4-122

4.2.6. Threatened and Endangered Fish Species .............................................................4-125

4.2.6.1. Description of the Affected Environment ............................................4-125

4.2.6.2. Impacts of Routine Events ...................................................................4-129

4.2.6.3. Impacts of Accidental Fuel Spills ........................................................4-134

4.2.6.4. Cumulative Impacts .............................................................................4-135

4.2.7. Commercial Fisheries............................................................................................4-139

4.2.7.1. Description of the Affected Environment ............................................4-139

4.2.7.2. Impacts of Routine Events ...................................................................4-145

4.2.7.3. Impacts of Accidental Fuel Spills ........................................................4-150

4.2.7.4. Cumulative Impacts .............................................................................4-150

4.2.8. Recreational Fisheries ...........................................................................................4-152

4.2.8.1. Description of the Affected Environment ............................................4-152

4.2.8.2. Impacts of Routine Events ...................................................................4-154

4.2.8.3. Impacts of Accidental Fuel Spills ........................................................4-157

4.2.8.4. Cumulative Impacts .............................................................................4-158

4.2.9. Recreational Resources .........................................................................................4-160

4.2.9.1. Description of the Affected Environment ............................................4-160

4.2.9.2. Impacts of Routine Events ...................................................................4-161

4.2.9.3. Impacts of Accidental Fuel Spills ........................................................4-163

4.2.9.4. Cumulative Impacts .............................................................................4-163

4.2.10. Archaeological Resources .....................................................................................4-165

4.2.10.1. Description of the Affected Environment ............................................4-165

4.2.10.2. Impacts of Routine Events ...................................................................4-167

4.2.10.3. Impacts of Accidental Fuel Spills ........................................................4-170

4.2.10.4. Cumulative Impacts .............................................................................4-170

4.2.11. Marine Protected Areas.........................................................................................4-172

4.2.11.1. Description of the Affected Environment ............................................4-172

4.2.11.2. Impacts of Routine Events ...................................................................4-175

4.2.11.3. Impacts of Accidental Fuel Spills ........................................................4-182

4.2.11.4. Cumulative Impacts .............................................................................4-182
viii Atlantic G&G Programmatic EIS

4.2.12. Other Marine Uses ................................................................................................4-186

4.2.12.1. Description of the Affected Environment ............................................4-186

4.2.12.2. Impacts of Routine Events ...................................................................4-192

4.2.12.3. Impacts of Accidental Fuel Spills ........................................................4-199

4.2.12.4. Cumulative Impacts .............................................................................4-199

4.2.13. Human Resources and Land Use...........................................................................4-202

4.2.13.1. Description of the Affected Environment ............................................4-202

4.2.13.2. Impacts of Routine Events ...................................................................4-206

4.2.13.3. Impacts of Accidental Fuel Spills ........................................................4-208

4.2.13.4. Cumulative Impacts .............................................................................4-208

4.3. Alternative B – The Proposed Action with Additional Mitigation ......................................4-209

4.3.1. Benthic Communities............................................................................................4-210

4.3.1.1. Impacts of Routine Activities...............................................................4-210

4.3.1.2. Impacts of Accidental Fuel Spills ........................................................4-212

4.3.1.3. Cumulative Impacts .............................................................................4-212

4.3.2. Marine Mammals ..................................................................................................4-212

4.3.2.1. Impacts of Routine Activities...............................................................4-213

4.3.2.2. Impacts of Accidental Fuel Spills ........................................................4-215

4.3.2.3. Cumulative Impacts .............................................................................4-215

4.3.3. Sea Turtles.............................................................................................................4-216

4.3.3.1. Impacts of Routine Activities...............................................................4-217

4.3.3.2. Impacts of Accidental Fuel Spills ........................................................4-219

4.3.3.3. Cumulative Impacts .............................................................................4-219

4.3.4. Marine and Coastal Birds......................................................................................4-220

4.3.4.1. Impacts of Routine Activities...............................................................4-220

4.3.4.2. Impacts of Accidental Fuel Spills ........................................................4-223

4.3.4.3. Cumulative Impacts .............................................................................4-223

4.3.5. Fisheries Resources and Essential Fish Habitat ....................................................4-223

4.3.5.1. Impacts of Routine Activities...............................................................4-224

4.3.5.2. Impacts of Accidental Fuel Spills ........................................................4-225

4.3.5.3. Cumulative Impacts .............................................................................4-226

4.3.6. Threatened and Endangered Fish Species .............................................................4-227

4.3.6.1. Impacts of Routine Activities...............................................................4-227

4.3.6.2. Impacts of Accidental Fuel Spills ........................................................4-229

4.3.6.3. Cumulative Impacts .............................................................................4-229

4.3.7. Commercial Fisheries............................................................................................4-230

4.3.7.1. Impacts of Routine Activities...............................................................4-230

4.3.7.2. Impacts of Accidental Fuel Spills ........................................................4-233

4.3.7.3. Cumulative Impacts .............................................................................4-233

4.3.8. Recreational Fisheries ...........................................................................................4-234

4.3.8.1. Impacts of Routine Activities...............................................................4-234

4.3.8.2. Impacts of Accidental Fuel Spills ........................................................4-237

4.3.8.3. Cumulative Impacts .............................................................................4-237

4.3.9. Recreational Resources .........................................................................................4-238

4.3.9.1. Impacts of Routine Activities...............................................................4-238

4.3.9.2. Impacts of Accidental Fuel Spills ........................................................4-240

4.3.9.3. Cumulative Impacts .............................................................................4-240

4.3.10. Archaeological Resources .....................................................................................4-241

4.3.10.1. Impacts of Routine Activities...............................................................4-241

4.3.10.2. Impacts of Accidental Fuel Spills ........................................................4-242

4.3.10.3. Cumulative Impacts .............................................................................4-242

4.3.11. Marine Protected Areas.........................................................................................4-243

4.3.11.1. Impacts of Routine Activities...............................................................4-243

4.3.11.2. Impacts of Accidental Fuel Spills ........................................................4-245

4.3.11.3. Cumulative Impacts .............................................................................4-245
Table of Contents ix 

4.3.12. Other Marine Uses ................................................................................................4-246

4.3.12.1. Impacts of Routine Activities...............................................................4-246

4.3.12.2. Impacts of Accidental Fuel Spills ........................................................4-248

4.3.12.3. Cumulative Impacts .............................................................................4-248

4.3.13. Human Resources and Land Use...........................................................................4-249

4.3.13.1. Impacts of Routine Activities...............................................................4-249

4.3.13.2. Impacts of Accidental Fuel Spills ........................................................4-251

4.3.13.3. Cumulative Impacts .............................................................................4-251

4.4. Alternative C – No Action for Oil and Gas G&G Activity, Status Quo for Renewable 

Energy and Marine Mineral G&G Activity .........................................................................4-252

4.4.1. Benthic Communities............................................................................................4-253

4.4.1.1. Impacts of Routine Activities...............................................................4-253

4.4.1.2. Impacts of Accidental Fuel Spills ........................................................4-254

4.4.1.3. Cumulative Impacts .............................................................................4-254

4.4.2. Marine Mammals ..................................................................................................4-255

4.4.2.1. Impacts of Routine Activities...............................................................4-255

4.4.2.2. Impacts of Accidental Fuel Spills ........................................................4-256

4.4.2.3. Cumulative Impacts .............................................................................4-256

4.4.3. Sea Turtles.............................................................................................................4-257

4.4.3.1. Impacts of Routine Activities...............................................................4-257

4.4.3.2. Impacts of Accidental Fuel Spills ........................................................4-258

4.4.3.3. Cumulative Impacts .............................................................................4-259

4.4.4. Marine and Coastal Birds......................................................................................4-259

4.4.4.1. Impacts of Routine Activities...............................................................4-260

4.4.4.2. Impacts of Accidental Fuel Spills ........................................................4-262

4.4.4.3. Cumulative Impacts .............................................................................4-263

4.4.5. Fisheries Resources and Essential Fish Habitat ....................................................4-263

4.4.5.1. Impacts of Routine Activities...............................................................4-263

4.4.5.2. Impacts of Accidental Fuel Spills ........................................................4-265

4.4.5.3. Cumulative Impacts .............................................................................4-265

4.4.6. Threatened and Endangered Fish Species .............................................................4-265

4.4.6.1. Impacts of Routine Activities...............................................................4-266

4.4.6.2. Impacts of Accidental Fuel Spills ........................................................4-267

4.4.6.3. Cumulative Impacts .............................................................................4-267

4.4.7. Commercial Fisheries............................................................................................4-268

4.4.7.1. Impacts of Routine Activities...............................................................4-268

4.4.7.2. Impacts of Accidental Fuel Spills ........................................................4-269

4.4.7.3. Cumulative Impacts .............................................................................4-269

4.4.8. Recreational Fisheries ...........................................................................................4-269

4.4.8.1. Impacts of Routine Activities...............................................................4-270

4.4.8.2. Impacts of Accidental Fuel Spills ........................................................4-270

4.4.8.3. Cumulative Impacts .............................................................................4-271

4.4.9. Recreational Resources .........................................................................................4-271

4.4.9.1. Impacts of Routine Activities...............................................................4-271

4.4.9.2. Impacts of Accidental Fuel Spills ........................................................4-272

4.4.9.3. Cumulative Impacts .............................................................................4-272

4.4.10. Archaeological Resources .....................................................................................4-272

4.4.10.1. Impacts of Routine Activities...............................................................4-272

4.4.10.2. Impacts of Accidental Fuel Spills ........................................................4-273

4.4.10.3. Cumulative Impacts .............................................................................4-273

4.4.11. Marine Protected Areas.........................................................................................4-273

4.4.11.1. Impacts of Routine Activities...............................................................4-274

4.4.11.2. Impacts of Accidental Fuel Spills ........................................................4-276

4.4.11.3. Cumulative Impacts .............................................................................4-276
x Atlantic G&G Programmatic EIS

4.4.12. Other Marine Uses ................................................................................................4-277

4.4.12.1. Impacts of Routine Activities...............................................................4-277

4.4.12.2. Impacts of Accidental Fuel Spills ........................................................4-278

4.4.12.3. Cumulative Impacts .............................................................................4-278

4.4.13. Human Resources and Land Use...........................................................................4-278

4.4.13.1. Impacts of Routine Activities...............................................................4-278

4.4.13.2. Impacts of Accidental Fuel Spills ........................................................4-279

4.4.13.3. Cumulative Impacts .............................................................................4-279

4.5. Other NEPA Considerations ................................................................................................4-279

4.5.1. Unavoidable Adverse Impacts of the Proposed Action.........................................4-279

4.5.2. Irreversible and Irretrievable Commitment of Resources .....................................4-280

4.5.3. Relationship Between Short-term Uses of the Environment and the 

Maintenance and Enhancement of Long-term Productivity..................................4-280

5. CONSULTATION AND COORDINATION .....................................................................................5-3

5.1. Development of the Proposed Action ......................................................................................5-3

5.2. Notice of Intent to Prepare a Programmatic EIS......................................................................5-3

5.3. Development of the Draft Programmatic EIS..........................................................................5-3

5.3.1. Comments Received During Scoping .......................................................................5-4

5.3.2. Cooperating Agency..................................................................................................5-4

5.4. Distribution of the Draft Programmatic EIS for Review and Comment..................................5-5

5.5. Public Hearings........................................................................................................................5-7

5.6. Coastal Zone Management Act................................................................................................5-8

5.7. Endangered Species Act...........................................................................................................5-9

5.8. Marine Mammal Protection Act ..............................................................................................5-9

5.9. Magnuson-Stevens Fishery Conservation and Management Act ............................................5-9

5.10. National Marine Sanctuary Act................................................................................................5-9

6. REFERENCES CITED........................................................................................................................6-3

7. PREPARERS .......................................................................................................................................7-3

7.1. BOEM Preparers and Reviewers .............................................................................................7-3

7.2. Contractor Preparers ................................................................................................................7-4

8. GLOSSARY ........................................................................................................................................8-3
Table of Contents xi 

Volume II 

Page 

FIGURES.........................................................................................................................................Figures-3 

TABLES ...........................................................................................................................................Tables-3 

APPENDICES 

A. Biological Assessment ............................................................................................................A-3 

B. State Coastal Zone Management Programs ............................................................................ B-1 

C. Existing Regulations, Protective Measures, and Mitigation ................................................... C-1 

D. Acoustic Modeling Report......................................................................................................D-1 

E. Marine Mammal Incidental Take Methodology, Analysis, and Results................................. E-1 

F. Physical and Environmental Settings...................................................................................... F-1

G. Recent Publications of the Environmental Studies Program, Atlantic Region, 2006 to 

Present.....................................................................................................................................G-3 

H. Marine Mammal Hearing and Sensitivity to Acoustic Impacts ..............................................H-1 

I. Sea Turtle Hearing and Sensitivity to Acoustic Impacts.......................................................... I-1 

J. Fish Hearing and Sensitivity to Acoustic Impacts ................................................................... J-1 

K. Cooperating Agency ...............................................................................................................K-3 

KEYWORD INDEX.....................................................................................................................Keyword-3 

List of Figures xiii 

LIST OF FIGURES 

Page 

Figure 1-1. Area of Interest for the Atlantic G&G Programmatic EIS.........................................Figures-3

Figure 1-2. Primary Steps in the NEPA Process for the Programmatic EIS. ...............................Figures-4

Figure 2-1. Time-Area Closures under Alternative A. .................................................................Figures-5

Figure 2-2. Summary of Speed Restrictions and Locations for Vessel Operators to Comply 

with the Right Whale Strike Reduction Rule (50 CFR 224.105)...............................Figures-6

Figure 2-3. Time-Area Closures under Alternative B. .................................................................Figures-7

Figure 2-4. Close-Up View of Time-Area Closures Offshore Brevard County under 

Alternative B..............................................................................................................Figures-8

Figure 3-1. Simple Illustration of a Marine Seismic Survey Using Streamers.............................Figures-9

Figure 3-2. Illustration of the Difference between 2D and 3D Streamer Survey Coverage. ........Figures-9

Figure 4-1. Area of Interest for the Proposed Action. ................................................................Figures-10

Figure 4-2. Seafloor Features along the Mid- and South Atlantic Continental Margin..............Figures-11

Figure 4-3. Distribution of Hard/Live Bottom Habitats and Collected Coral Locations 

in the Area of Interest...............................................................................................Figures-12

Figure 4-4. Location of Habitat Areas of Particular Concern (HAPCs) Designated by the 

South Atlantic Fishery Management Council and New England Fishery 

Management Council. ..............................................................................................Figures-13

Figure 4-5. Location of the Blake Ridge Diapir Site Studied by Van Dover et al. (2003).........Figures-14

Figure 4-6. Artificial Reefs in the Area of Interest.....................................................................Figures-15

Figure 4-7. North Atlantic Right Whale Critical Habitat and Seasonal Management Areas .....Figures-16

Figure 4-8. North Atlantic Right Whale Seasonal Distribution and Habitat Use. ......................Figures-17

Figure 4-9. Distribution of Fin Whale Sightings from NEFSC and SEFSC Shipboard and 

Aerial Surveys during the Summers of 1998, 1999, 2002, 2004, 2006, and 

2007..........................................................................................................................Figures-18

Figure 4-10. Distribution of Humpback Whale Sightings from NEFSC and SEFSC 

Shipboard and Aerial Surveys during the Summers of 1998, 1999, 2002, 2004, 

2006, and 2007.........................................................................................................Figures-19

Figure 4-11. Distribution of Sei Whale Sightings from NEFSC and SEFSC Shipboard and 

Aerial Surveys during the Summers of 1998, 1999, 2002, 2004, 2006, and 

2007). .......................................................................................................................Figures-20

Figure 4-12. Distribution of Sperm Whale Sightings from NEFSC and SEFSC Shipboard 

and Aerial Surveys during the Summer in 1998, 1999, 2002, 2004, and 2006) ......Figures-21

Figure 4-13. Florida Manatee Critical Habitat..............................................................................Figures-22

Figure 4-14. Densities of Sea Turtle Nests Reported for Individual Counties within the Area 

of Interest for the 2010 Nesting Season. ..................................................................Figures-23

Figure 4-15. Location of the Four Recovery Units for the Loggerhead Turtle in the U.S. ..........Figures-24

Figure 4-16. Estimated Annual Number of Loggerhead Nests in the Southeastern U.S., 

Bahamas (including Cay Sal Bank), Cuba, and Mexico from 2001-2008...............Figures-24

Figure 4-17. Atlantic Flyway Migratory Routes...........................................................................Figures-25
xiv Atlantic G&G Programmatic EIS

Figure 4-18. Location of Critical Habitat for the Smalltooth Sawfish..........................................Figures-26

Figure 4-19. Locations of all Smalltooth Sawfish Sightings Recorded from 1999-2009.............Figures-27

Figure 4-20. Distinct Population Segments (DPSs) for the Atlantic Sturgeon.............................Figures-28

Figure 4-21. Commercial Landings and Value by Month within the Area of Interest 

in 2009 .....................................................................................................................Figures-29

Figure 4-22. Commercial Landings and Value by Gear Type within the Area of Interest 

in 2009. ....................................................................................................................Figures-29

Figure 4-23. Locations of Selected Seasonal and/or Area Closures to Commercial Fishing 

in Federal Waters Offshore the Mid-Atlantic and South Atlantic States.................Figures-30

Figure 4-24. Regulated Trap/Pot Areas under the Atlantic Large Whale Take Reduction 

Plan. .........................................................................................................................Figures-31

Figure 4-25. Regulated Gillnet Areas under the Atlantic Large Whale Take Reduction Plan. ....Figures-31

Figure 4-26. Numbers of Recreational Angler Trips by Individual States within the Area 

of Interest from 2006 through 2009. ........................................................................Figures-32

Figure 4-27. Numbers of Recreational Angler Trips by Month within the Area of Interest 

from 2006 through 2009. .........................................................................................Figures-32

Figure 4-28. Numbers of Recreational Angler Trips (stacked) by Fishing Location in the 

Mid-Atlantic States (Delaware, Maryland, and Virginia) and South Atlantic 

States (North Carolina, South Carolina, Georgia, and the Florida East Coast) 

from 2006 through 2009. .........................................................................................Figures-33

Figure 4-29. Numbers and Types of Fishes Landed by Recreational Anglers in the 

Mid-Atlantic States (Delaware, Maryland, and Virginia) from 2006 through 

2009). .......................................................................................................................Figures-33

Figure 4-30. Numbers and Types of Fishes Landed by Recreational Anglers in the South 

Atlantic States (North Carolina, South Carolina, Georgia, and the Florida East 

Coast) from 2006 through 2009. ..............................................................................Figures-34

Figure 4-31. Shipwrecks and Obstructions in the Area of Interest...............................................Figures-35

Figure 4-32. Model Showing Location of Paleochannels within the Georgia Bight....................Figures-36

Figure 4-33. Marine Protected Areas along Coastal and Nearshore Waters of Mid-Atlantic 

and South Atlantic States .........................................................................................Figures-37

Figure 4-34. Deepwater Marine Protected Areas Designated by the South Atlantic Fishery 

Management Council (SAFMC)..............................................................................Figures-38

Figure 4-35. State-Designated Marine Protected Areas along the Mid-Atlantic and South 

Atlantic Coasts. ........................................................................................................Figures-39

Figure 4-36. Aids to Navigation, Shipping Lanes, Precaution Areas, Fairways, and Traffic 

Separation Schemes along the Atlantic Coast..........................................................Figures-40

Figure 4-37. Military Use, National Aeronautics and Space Administration (NASA)-

Restricted, and Ordnance Disposal Areas along the Atlantic Coast. .......................Figures-41

Figure 4-38. Outer Continental Shelf Sand and Gravel Borrow Areas along the Mid-Atlantic 

and South Atlantic Coasts. .......................................................................................Figures-42

Figure 4-39. Identified Potential Wind Energy Facility Project Areas and Limited Leases 

for Wind Resource Assessment along the Mid-Atlantic Coast................................Figures-43

Figure 4-40. Ocean Dredged Material Disposal Sites along the Mid-Atlantic and South 

Atlantic Coasts. ........................................................................................................Figures-44
List of Figures xv 

Figure 4-41. Locations of the 51 Wells Drilled on the Atlantic Outer Continental Shelf 

(OCS) between 1975 and 1984. ...............................................................................Figures-45

Figure 4-42. Location of U.S. Navy Research Towers in the Georgia Bight that are Part 

of the South Atlantic Bight Synoptic Offshore Observational Network 

(SABSOON) Operated by Skidaway Institute of Oceanography ............................Figures-46

Figure 5-1. Map with State-by-State Distribution of Origin of Comments................................Figures-47

List of Tables xvii 

LIST OF TABLES 

Page 

Table S-1. Summary of Mitigation Measures Included in Alternatives A and B.................. (Volume I) x

Table 1-1. Major Federal Laws and Regulations Applicable to the Proposed Action ................. Tables-3

Table 2-1. Summary of Mitigation Measures Included in Alternatives A and B......................... Tables-5

Table 2-2. Comparison of Impact Levels for Alternatives A, B, and C....................................... Tables-7

Table 3-1. Types of G&G Activities Included in This Programmatic EIS ................................ Tables-10

Table 3-2. Program Area, G&G Activity, Permitting Authority, and Typical NEPA 

Action........................................................................................................................ Tables-11

Table 3-3. Projected Levels of G&G Activities for Oil and Gas Exploration in the 

Mid-Atlantic and South Atlantic Planning Areas, 2012-2020 .................................. Tables-12

Table 3-4. Projected Levels of Miscellaneous G&G Activities for Oil and Gas 

Exploration in the Mid-Atlantic and South Atlantic Planning Areas, 2012-2020 .... Tables-13

Table 3-5. Locations and Areas for Renewable Energy Site Characterization and 

Assessment Activities Offshore the Mid-Atlantic and South Atlantic 

Planning Areas .......................................................................................................... Tables-14

Table 3-6. Projected Levels of G&G Activities for Renewable Energy Site 

Characterization and Assessment in the Mid-Atlantic and South Atlantic 

Planning Areas, 2012-2020....................................................................................... Tables-15

Table 3-7. Projected Levels of High-Resolution Geophysical Surveys for OCS Sand 

Borrow Projects in the Mid-Atlantic and South Atlantic Planning Areas, 

2012-2020 ................................................................................................................. Tables-16

Table 3-8. Projected Levels of Geotechnical Surveys for OCS Sand Borrow Projects 

in the Mid-Atlantic and South Atlantic Planning Areas, 2012-2020 ........................ Tables-17

Table 3-9. Scenario Elements for Proposed G&G Activities in the Mid-Atlantic and 

South Atlantic Planning Areas, 2012-2020............................................................... Tables-18

Table 3-10. Impact-Producing Factors......................................................................................... Tables-21

Table 3-11. Characteristics of Active Acoustic Sound Sources Included in the Proposed 

Action........................................................................................................................ Tables-22

Table 4-1. Impact-Producing Factors for G&G Activities ......................................................... Tables-23

Table 4-2. Preliminary Screening of Potential Impacts (Leopold Matrix)................................. Tables-24

Table 4-3. Sources for G&G Impact-Producing Factors............................................................ Tables-25

Table 4-4. Marine Mammals Potentially Occurring in the Area of Interest............................... Tables-26

Table 4-5. Designated U.S. and Canadian Seasonal Management Areas for the North 

Atlantic Right Whale ................................................................................................ Tables-28

Table 4-6. Existing and Proposed Injury and Behavior Exposure Criteria for Cetaceans 

and Pinnipeds Exposed to Pulsed Sounds................................................................. Tables-28

Table 4-7. Functional Marine Mammal Hearing Groups, Associated Auditory 

Bandwidths, and Marine Mammal Species Present in the Area of Interest.............. Tables-29

Table 4-8. Summary of Radial Distances to the 160-dB and 180-dB (rms) Isopleths 

from a Single Pulse for Various Equipment ............................................................. Tables-30
xviii Atlantic G&G Programmatic EIS 

Table 4-9. Annual Level A Take Estimates from Seismic Airgun Sources Using Southall 

et al. (2007) Criteria for Marine Mammal Species during the Project Period 

(2012-2020)............................................................................................................... Tables-31

Table 4-10. Annual Level A Takes Estimates from Seismic Airgun Sources Using 180-dB 

Criteria for Marine Mammal Species during the Project Period (2012-2020).......... Tables-32

Table 4-11. Annual Level B Take Estimates (160-dB criteria) from Airgun Surveys for 

Marine Mammal Species during the Project Period (2012-2020)............................. Tables-33

Table 4-12. Annual Level A Take Estimates from All Non-Airgun High-Resolution 

Geophysical Surveys Using Southall et al. (2007) Criteria for Marine Mammal 

Species during the Project Period (2012-2020) ........................................................ Tables-34

Table 4-13. Annual Level A Take Estimates from All Non-Airgun High-Resolution 

Geophysical Surveys Using 180-dB Criteria for Marine Mammal Species 

during the Project Period (2012-2020)...................................................................... Tables-35

Table 4-14. Annual Level B Take Estimates from All Non-Airgun High-Resolution 

Geophysical Surveys Using 160-dB Criteria for Marine Mammal Species 

during the Project Period (2012-2020)...................................................................... Tables-36

Table 4-15. Sea Turtles Occurring in the Area of Interest ........................................................... Tables-37

Table 4-16 Families of Seabirds, Waterfowl, and Shorebirds Occurring in the Area 

of Interest .................................................................................................................. Tables-38

Table 4-17. Important Bird Areas within Offshore, Nearshore, and Coastal Habitats 

Within and Adjacent to the Area of Interest ............................................................. Tables-40

Table 4-18. Plant, Invertebrate, and Fish Species and Species Groups Broadly Associated 

with Demersal and Pelagic Habitats in the Area of Interest Managed by the 

South Atlantic Fishery Management Council, Mid-Atlantic Fishery 

Management Council, New England Fishery Management Council, and/or 

Highly Migratory Species Office of the National Marine Fisheries Service ............ Tables-41

Table 4-19. Hard Bottom Species with Essential Fish Habitat Identified within the Area 

of Interest .................................................................................................................. Tables-42

Table 4-20. Soft Bottom Species and Life Stages with Essential Fish Habitat Identified 

within the Area of Interest ........................................................................................ Tables-44

Table 4-21. Coastal Pelagic Species and Life Stages with Essential Fish Habitat Identified 

within the Area of Interest ........................................................................................ Tables-48

Table 4-22. Small Coastal Shark Species and Life Stages with Essential Fish Habitat 

Identified within the Area of Interest........................................................................ Tables-50

Table 4-23. Large Coastal Shark Species and Life Stages with Essential Fish Habitat 

Identified within the Area of Interest........................................................................ Tables-51

Table 4-24. Highly Migratory Fishes and Life Stages with Essential Fish Habitat Identified 

within the Area of Interest ........................................................................................ Tables-54

Table 4-25. Pelagic Shark Species and Life Stages with Essential Fish Habitat Identified 

within the Area of Interest ........................................................................................ Tables-56

Table 4-26. Summary of Marine Fish Hearing Sensitivity .......................................................... Tables-57

Table 4-27. Commercial Landings within the Area of Interest during 2006-2009 ...................... Tables-58

Table 4-28. Primary Commercial Species Landed with the Most Economic Value for Each 

State within the Area of Interest during 2006-2009.................................................. Tables-58
List of Tables xix 

Table 4-29. Commercial Fishing Landings and Value for Each State within the Area 

of Interest during 2009.............................................................................................. Tables-59

Table 4-30. Seasonal and/or Area Closures to Commercial Fishing in Federal Waters 

Offshore the Mid-Atlantic and South Atlantic States ............................................... Tables-60

Table 4-31. Partial List of Recreational Fishing Tournaments within the Area of Interest ......... Tables-62

Table 4-32. Selected Parks, Seashores, Recreation Areas, and Wildlife Refuges along the 

Mid-Atlantic and South Atlantic Coasts ................................................................... Tables-63

Table 4-33. Types of Recreational Activities by Location in the Area of Interest and along 

the Mid-Atlantic and South Atlantic Coasts ............................................................. Tables-64

Table 4-34. Economic Contribution of Marine-Based Tourism and Recreation to State 

Economies in 2004.................................................................................................... Tables-64

Table 4-35. Economic Contribution of Leisure and Hospitality to Coastal Economies 

in 2008 ...................................................................................................................... Tables-65

Table 4-36. Summary of Federal, Partnership, Federal Fishery Management, and State 

Designated Marine Protected Areas Listed in the National System of Marine 

Protected Areas ......................................................................................................... Tables-66

Table 4-37. Population of the Metropolitan Statistical Areas Associated with Five Atlantic 

Coast Ports in 2000 and 2010 ................................................................................... Tables-71

Table 4-38. Gross Domestic Product (GDP) of the Metropolitan Statistical Areas 

Associated with Five Atlantic Coast Ports in 2009................................................... Tables-71

Table 4-39. Labor Force and Unemployment in the Metropolitan Statistical Areas 

Associated with Five Atlantic Coast Ports in January 2011 ..................................... Tables-71

Table 4-40. Minority Presence in Metropolitan Statistical Areas Associated with Five 

Atlantic Coast Ports in 2010, Compared with State and National Averages ............ Tables-72

Table 4-41. Low-Income Presence in Metropolitan Statistical Areas Associated with Five 

Atlantic Coast Ports in 2009, Compared with State and National Averages ............ Tables-73

Table 4-42. Minority Presence in Fishing Communities in 2000 in States Adjacent to the 

Area of Interest ......................................................................................................... Tables-74

Table 4-43. Low-Income Presence in Fishing Communities in States Adjacent to the Area 

of Interest in 2000 ..................................................................................................... Tables-75

Table 5-1. EFH Consultation Requirements and the Applicable Programmatic EIS 

Chapters .................................................................................................................... Tables-76

Table 5-2. NMSA Consultation Requirements and the Applicable Programmatic EIS 

Chapters .................................................................................................................... Tables-77 

FIGURES

Figures Figures-3 

Figure 1-1. Area of Interest for the Atlantic G&G Programmatic EIS. 
Figures-4 Atlantic G&G Programmatic EIS 

Initial Notice of Intent 

January 21, 2009 

Initial Scoping Period (60 days) 

(January 21 – March 23, 2009)

Notice of Intent 

April 2, 2010

Reopened Scoping Period (45 days) 

and Public Scoping Meetings 

(April 2 – May 17, 2010) 

Preparation of Draft Programmatic EIS 

Public Comment Period (60 days) 

and Public Hearings 

(March – April 2012) 

Preparation of Final Programmatic EIS 

Notice of Availability of Final Programmatic EIS 

Public Comment Period 

(30 days) 

Record of Decision 

Figure 1-2. Primary Steps in the NEPA Process for the Programmatic 

EIS. 
Figures Figures-5 

Figure 2-1. Time-Area Closures under Alternative A. 
Figures-6 Atlantic G&G Programmatic EIS 

Figure 2-2. Summary of Speed Restrictions and Locations for Vessel Operators to Comply with the Right 

Whale Strike Reduction Rule (50 CFR 224.105) (USDOC, NOAA, 2011). 
Figures Figures-7 

Figure 2-3. Time-Area Closures under Alternative B. 
Figures-8 Atlantic G&G Programmatic EIS 

Figure 2-4. Close-Up View of Time-Area Closures Offshore Brevard County under Alternative B. 
Figures Figures-9 

Figure 3-1. Simple Illustration of a Marine Seismic Survey Using Streamers. 

Figure 3-2. Illustration of the Difference between 2D and 3D Streamer Survey Coverage 

(Spacing between adjacent ship tracks for 2D will typically be greater than 

1 km [0.6 mi]. Spacing for 3D surveys varies, but the data density typically 

will be 15-20 times greater than for 2D surveys) (IAGC, 2011; Credit Jack 

Caldwell and Chris Walker). 
Figures-10 Atlantic G&G Programmatic EIS 

Figure 4-1. Area of Interest for the Proposed Action. 
Figures Figures-11 

Figure 4-2. Seafloor Features along the Mid- and South Atlantic Continental Margin. 
Figures-12 Atlantic G&G Programmatic EIS 

Figure 4-3. Distribution of Hard/Live Bottom Habitats and Collected Coral Locations in the Area of 

Interest (Hard/live bottom habitats [from the Virginia/North Carolina border southward] 

are from the SEAMAP database. Collected coral locations [from Cape Hatteras 

northward] are from online searches of museum records, courtesy of S. Ross and 

M. Rhode, University of North Carolina, Wilmington). 
Figures Figures-13 

Figure 4-4. Location of Habitat Areas of Particular Concern (HAPCs) Designated by the South Atlantic 

Fishery Management Council and New England Fishery Management Council. 
Figures-14 Atlantic G&G Programmatic EIS 

Figure 4-5. Location of the Blake Ridge Diapir Site Studied by Van Dover et al. (2003) (Star 

indicates study site; shaded area indicates region of gas hydrate deposits. 

Bathymetry is shown in meters). 
Figures Figures-15 

Figure 4-6. Artificial Reefs in the Area of Interest (Delaware Division of Fish and Wildlife, 2010; 

Florida Fish and Wildlife Conservation Commission, Fish and Wildlife Research 

Institute, 2011; Georgia Department of Natural Resources, Coastal Resources Division, 

2011; Maryland Department of Natural Resources, 2011; North Carolina Division of 

Marine Fisheries, 2011; South Carolina Department of Natural Resources, Marine 

Resources Division, 2011; Virginia Marine Resources Commission, 2011). 
Figures-16 Atlantic G&G Programmatic EIS 

Figure 4-7. North Atlantic Right Whale Critical Habitat and Seasonal Management Areas 

(50 CFR 224.105). 
Figures Figures-17 

Figure 4-8. North Atlantic Right Whale Seasonal Distribution and Habitat Use (NOAA Fisheries Service, 

Southeast Regional Office, St. Petersburg, Florida, http://sero.nmfs.noaa.gov). 
Figures-18 Atlantic G&G Programmatic EIS 

Figure 4-9. Distribution of Fin Whale Sightings from NEFSC and SEFSC Shipboard and Aerial Surveys 

during the Summers of 1998, 1999, 2002, 2004, 2006, and 2007 (Isobaths are the 100-m 

(328-ft), 1,000-m (3,280-ft), and 4,000-m (13,124-ft) depth contours) (Waring et al., 2010). 
Figures Figures-19 

Figure 4-10. Distribution of Humpback Whale Sightings from NEFSC and SEFSC Shipboard and Aerial 

Surveys during the Summers of 1998, 1999, 2002, 2004, 2006, and 2007 (Isobaths are the 

100-m (328-ft), 1,000-m (3,280-ft), and 4,000-m (13,124-ft) depth contours) (Waring et al., 

2010). 
Figures-20 Atlantic G&G Programmatic EIS 

Figure 4-11. Distribution of Sei Whale Sightings from NEFSC and SEFSC Shipboard and Aerial Surveys 

during the Summers of 1998, 1999, 2002, 2004, 2006, and 2007) (Isobaths are the 100-m 

(328-ft), 1,000-m (3,280-ft), and 4,000-m (13,124-ft) depth contours) (Waring et al., 2010). 
Figures Figures-21 

Figure 4-12. Distribution of Sperm Whale Sightings from NEFSC and SEFSC Shipboard and Aerial Surveys 

during the Summer in 1998, 1999, 2002, 2004, and 2006) (Isobaths are the 100-m (328-ft), 

1,000-m (3,280-ft), and 4,000-m (13,124-ft) depth contours) (Waring et al., 2010). 
Figures-22 Atlantic G&G Programmatic EIS 

Figure 4-13. Florida Manatee Critical Habitat (50 CFR 17.95). 
Figures Figures-23 

Figure 4-14. Densities of Sea Turtle Nests Reported for Individual Counties within the Area of Interest for 

the 2010 Nesting Season (http://www.seaturtle.org/nestdb/ [North Carolina, South Carolina, 

and Georgia]; http://myfwc.com/research/wildlife/sea-turtles/nesting/ [Florida]). 
Figures-24 Atlantic G&G Programmatic EIS 

NRU

PFRU

NGMRU

DTRU

PFRU

Figure 4-15. Location of the Four Recovery Units for the Loggerhead Turtle in the 

U.S. (NRU = Northern Recovery Unit, PFRU = Peninsular Florida 

Recovery Unit, DTRU = Dry Tortugas Recovery Unit, NGMRU = 

Northern Gulf of Mexico Recovery Unit) (USDOC, NMFS and USDOI, 

FWS, 2008). 

Figure 4-16. Estimated Annual Number of Loggerhead Nests in the Southeastern 

U.S., Bahamas (including Cay Sal Bank), Cuba, and Mexico from 

2001-2008 (USDOC, NMFS and USDOI, FWS, 2008). 
Figures Figures-25 

Figure 4-17. Atlantic Flyway Migratory Routes (http://birdnature.com/flyways.html). 
Figures-26 Atlantic G&G Programmatic EIS 

Figure 4-18. Location of Critical Habitat for the Smalltooth Sawfish (USDOC, NMFS, 2011n). 
Figures Figures-27 

Figure 4-19. Locations of all Smalltooth Sawfish Sightings Recorded from 1999-2009 (National 

Sawfish Encounter Database, 2011). 
Figures-28 Atlantic G&G Programmatic EIS 

Chesapeake 

Bay DPS

eake 

New York 

Bight DPS

New York 

Bight DPS

Figure 4-20. Distinct Population Segments (DPSs) for the Atlantic Sturgeon (Atlantic Sturgeon Status 

Review Team, 2007). 
Figures Figures-29 

Figure 4-21. Commercial Landings and Value by Month within the Area of Interest in 

2009 (USDOC, NMFS, 2011k). 

Figure 4-22. Commercial Landings and Value by Gear Type within the Area of Interest in 2009 

(USDOC, NMFS, 2011k). 
Figures-30 Atlantic G&G Programmatic EIS 

Figure 4-23. Locations of Selected Seasonal and/or Area Closures to Commercial Fishing in Federal 

Waters Offshore the Mid-Atlantic and South Atlantic States (additional restrictions apply in 

Habitat Areas of Particular Concern [see Figure 4-4]). 
Figures Figures-31 

Figure 4-24. Regulated Trap/Pot Areas under the Atlantic Large Whale Take Reduction 

Plan (USDOC, NMFS, 2010e). 

Figure 4-25. Regulated Gillnet Areas under the Atlantic Large Whale Take Reduction 

Plan (USDOC, NMFS, 2010e). 
Figures-32 Atlantic G&G Programmatic EIS Number of Angler Trips

Figure 4-26. Numbers of Recreational Angler Trips by Individual States within the Area of Interest 

from 2006 through 2009 (USDOC, NMFS, 2011l). 

Figure 4-27. Numbers of Recreational Angler Trips by Month within the Area of Interest from 

2006 through 2009 (USDOC, NMFS, 2011l). 
Figures Figures-33 

Figure 4-28. Numbers of Recreational Angler Trips (stacked) by Fishing Location in the 

Mid-Atlantic States (Delaware, Maryland, and Virginia) and South Atlantic States 

(North Carolina, South Carolina, Georgia, and the Florida East Coast) from 2006 

through 2009 (USDOC, NMFS, 2011l). 

Figure 4-29. Numbers and Types of Fishes Landed by Recreational Anglers in the Mid-Atlantic 

States (Delaware, Maryland, and Virginia) from 2006 through 2009) (USDOC, 

NMFS, 2011l). 
Figures-34 Atlantic G&G Programmatic EIS 

Figure 4-30. Numbers and Types of Fishes Landed by Recreational Anglers in the South 

Atlantic States (North Carolina, South Carolina, Georgia, and the Florida East 

Coast) from 2006 through 2009 (USDOC, NMFS, 2011l). 
Figures Figures-35 

Figure 4-31. Shipwrecks and Obstructions in the Area of Interest. 
Figures-36 Atlantic G&G Programmatic EIS 

Figure 4-32. Model Showing Location of Paleochannels within the Georgia Bight (TRC Environmental 

Corporation, 2011). 
Figures Figures-37 

Figure 4-33. Marine Protected Areas along Coastal and Nearshore Waters of Mid-Atlantic and South Atlantic 

States (USDOC, NOAA, National Marine Protected Areas Center, http://www.mpa.gov). 
Figures-38 Atlantic G&G Programmatic EIS 

Figure 4-34. Deepwater Marine Protected Areas Designated by the South Atlantic Fishery Management 

Council (SAFMC) (SAFMC, 2011b). 
Figures Figures-39 

Figure 4-35. State-Designated Marine Protected Areas along the Mid-Atlantic and South Atlantic Coasts 

(USDOC, NOAA, National Marine Protected Areas Center, http://www.mpa.gov). 
Figures-40 Atlantic G&G Programmatic EIS 

Figure 4-36. Aids to Navigation, Shipping Lanes, Precaution Areas, Fairways, and Traffic Separation 

Schemes along the Atlantic Coast (Multipurpose Marine Cadastre, 2011). 
Figures Figures-41 

Figure 4-37. Military Use, National Aeronautics and Space Administration (NASA)-Restricted, and 

Ordnance Disposal Areas along the Atlantic Coast (Naval Facilities Engineering Command; 

33 CFR 334.595; 33 CFR 334.130). 
Figures-42 Atlantic G&G Programmatic EIS 

Figure 4-38. Outer Continental Shelf Sand and Gravel Borrow Areas along the Mid-Atlantic and South 

Atlantic Coasts. 
Figures Figures-43 

Figure 4-39. Identified Potential Wind Energy Facility Project Areas and Limited Leases for Wind Resource 

Assessment along the Mid-Atlantic Coast (USDOI, BOEM, 2011k,l,m,n). 
Figures-44 Atlantic G&G Programmatic EIS 

Figure 4-40. Ocean Dredged Material Disposal Sites along the Mid-Atlantic and South Atlantic Coasts. 
Figures Figures-45 

Figure 4-41. Locations of the 51 Wells Drilled on the Atlantic Outer Continental Shelf (OCS) between 

1975 and 1984 (also shown is the location of the proposed OCS oil and gas Lease Sale 220 

area offshore Virginia [sale canceled July 28, 2010]). 
Figures-46 Atlantic G&G Programmatic EIS 

Figure 4-42. Location of U.S. Navy Research Towers in the Georgia Bight that are Part of the South Atlantic Bight 

Synoptic Offshore Observational Network (SABSOON) Operated by Skidaway Institute of 

Oceanography (Skidaway Institute of Oceanography, 2011). 
Figures Figures-47 

Figure 5-1. Map with State-by-State Distribution of Origin of Comments. 

TABLES

Tables Tables-3 

Table 1-1 

 

Major Federal Laws and Regulations Applicable to the Proposed Action 

Regulation or Law Citation 

Outer Continental Shelf Lands Act 43 U.S.C. 1331 et seq.

National Environmental Policy Act of 1969 42 U.S.C. 4321-4347 

40 CFR 1500-1508 

Coastal Zone Management Act of 1972 16 U.S.C. 1451 et seq., 

15 CFR 930.76

Endangered Species Act of 1973 16 U.S.C. 1631 et seq. 

Magnuson-Stevens Fishery Conservation and Management Act 16 U.S.C. 1251 et seq. 

Essential Fish Habitat 

1996 reauthorization of the 

Magnuson-Stevens Fishery 

Conservation and Management Act 

Essential Fish Habitat Consultation 50 CFR 600.905-930 

Marine Mammal Protection Act 16 U.S.C. 1361 et seq. 

Clean Air Act 42 U.S.C. 7401 et seq., 

40 CFR 55 

Clean Water Act Amendment to Federal Water 

Pollution Control Act of 1972 

Clean Water Act—National Pollutant Discharge Elimination System Section 316(b) of the Clean Water Act

Harmful Algal Bloom and Hypoxia Research and Control Act P.L. 105-383 

Oil Pollution Act of 1990 33 U.S.C. 2701 et seq., 

Executive Order 12777 

Comprehensive Environmental Response, Compensation, and 

Liability Act of 1980 42 U.S.C. 9601 et seq. 

Resource Conservation and Recovery Act 42 U.S.C. 6901 et seq. 

Marine Plastic Pollution Research and Control Act 33 U.S.C. 1901 et seq. 

National Fishing Enhancement Act of 1984 33 U.S.C. 2601 et seq. 

Fishermen’s Contingency Fund 43 U.S.C. 1841-1846 

Ports and Waterways Safety Act of 1972 33 U.S.C. 1223 et seq. 

Marine and Estuarine Protection Acts 33 U.S.C. 1401 et seq. 

Marine Protection, Research, and Sanctuaries Act of 1972 P.L. 92-532 

National Estuarine Research Reserves 16 U.S.C. § 1461, Section 315 

National Estuary Program P.L. 104-4 

Coastal Barrier Resources Act 16 U.S.C. 3501 et seq. 

National Historic Preservation Act 16 U.S.C. 470 et seq. 

Rivers and Harbors Act of 1899 33 U.S.C. 401 et seq. 

Occupational Safety and Health Act of 1970 29 U.S.C. 651-678q 

Energy Policy Act of 2005 P.L. 109-58 

Marine Debris Research, Prevention, and Reduction Act P.L. 109-449 

American Indian Religious Freedom Act of 1978 P.L. 95-341, 

42 U.S.C. 1996 and 1996a 

Federal Aviation Act of 1958 

Federal Aviation Act of 1958 was 

repealed by the recodification of 

49 U.S.C. (P.L. 103-272) 
Tables-4 Atlantic G&G Programmatic EIS 

Table 1-1. Major Federal Laws and Regulations Applicable to the Proposed Action (continued) 

Regulation or Law Citation 

Migratory Bird Treaty Act of 1918 16 U.S.C. 703-712; Ch. 128; 

07/13/1918; 40 Stat. 755 

Submerged Lands Act of 1953 43 U.S.C. §§ 1301-1315 (2002) 

49 U.S.C. 44718: Structures Interfering with Air Commerce 49 U.S.C. 44718 

U.S. Coast Guard Regulations 

Marking of Obstructions 

Executive Order 11988: Floodplain Management 42 FR 26951 (1977), amended by 

Executive Order 12148 (7/20/79) 

Executive Order 11990: Protection of Wetlands 42 FR 26961 (1977), amended by 

Executive Order 12608 (9/9/87) 

Executive Order 12114: Environmental Effects Abroad 44 FR 1957 (1979) 

Executive Order 12898: Environmental Justice 59 FR 5517 (1994) 

Executive Order 13007: Indian Sacred Sites 61 FR 26771-26772 (1996) 

Executive Order 13089: Coral Reef Protection 63 FR 32701-32703 (1998) 

Executive Order 13175: Consultation and Coordination with Indian Tribal 

Governments 65 FR 67249-67252 (2000) 

Executive Order 13186: Responsibilities of Federal Agencies to Protect 

Migratory Birds 66 FR 3853 (2001) 

Executive Order 13547: Stewardship of the Ocean, Our Coasts, and the 

Great Lakes 75 FR 43023 (2010) 

Source: Matthews and Cameron, 2010. 
Table 2-1 Summary of Mitigation Measures Included in Alternatives A and B P

Mitigation Measure Description Applicable Survey Types OG 

Time-Area Closure for North Atlantic Right Whales Under Alternative A, no G&G surveys using air guns would be authorized within the North Atlantic right whale critical habitat area from November 15 through April 15 nor within the Mid-Atlantic and Southeast U.S. Seasonal Management Areas (SMAs) during the times when vessel speed restrictions are in effect under the Right Whale Ship Strike Reduction Rule (50 CFR 224.105). However, HRG surveys proposed in critical habitat and SMAs from November 15 through April 15 may be considered on a case-by-case basis only if: (1) they are proposed for renewable energy or marine minerals operations; and (2) they use acoustic sources other than air guns. The coincidence is necessary because of other biological use windows or project monitoring requirements. Any such authorization may include additional mitigation and monitoring requirements to avoid or significantly reduce impacts on right whales. Other supporting surveys (e.g., biological surveys) would not be affected by this restriction. All vessel surveys (restrictions vary depending on survey type as indicated) X Expanded Time-Area Closure for North Atlantic Right Whales Under Alternative B the expanded time-area closure for North Atlantic right whales would be a 37-km (20-nmi) wide zone from shore extending continuously from Delaware Bay to the southern limit of the AOI. No G&G surveys using airguns would be authorized within these expanded closure areas during the times when vessel speed restrictions are in effect in adjacent SMAs under 50 CFR 224.105. Exceptions for surveys are as stated for the time- areas closures for Alternative A. All vessel surveys (restrictions vary depending on survey type as indicated) X Time-Area Closure to Protect Nesting Sea Turtles Offshore Brevard County, Florida Alternative B would include a time-area closure in near-coastal waters offshore Brevard County, Florida during the sea turtle nesting season (May 1 to October 31). No airgun surveys would be authorized within the closure area during this time. Other surveys in the closure area would be reviewed on a case-by-case basis, and authorizations may include additional mitigation and monitoring requirements to avoid or reduce impacts on sea turtles. All vessel surveys (restrictions vary depending on survey type as indicated) X Seismic Survey Protocol Under both Alternatives A and B, all authorizations for seismic surveys would include a survey protocol that specifies mitigation measures for protected species, including ramp-up, visual monitoring of an exclusion zone by protected species observers prior to and during seismic surveys, and startup and shutdown requirements (see Appendix L). The protocol includes the optional use of PAM to help detect vocalizing marine mammals. All deep penetration seismic surveys and all HRG surveys using airguns as sound source X Seismic Survey Protocol with Required PAM Under Alternative B, the use of PAM would be required as part of the seismic survey 

protocol. The purpose would be to improve detection of marine mammals prior to and during seismic surveys so that impacts can be avoided by shutting down or delaying startup ofairgun arrays until the animals are outside the exclusion zone.

All deep penetration seismic surveys and all HRG surveys using airguns as sound source 

X 

HRG Survey Protocol 

Under both Alternatives A and B, all authorizations for non-airgun HRG surveys would include a survey protocol that specifies mitigation measures for protected species, including ramp-up, visual monitoring of an exclusion zone by protected species observers prior to and during surveys, and startup and shutdown requirements (see Appendix L).

All HRG surveys not

using airguns as sound source 

-- 

Separation between Simultaneous Seismic Surveys 

Under Alternative B, a 40-km (25-mi) separation distance would be maintained between 

simultaneously operating deep penetration seismic surveys to limit ensonification of large areas of the AOI at the same time.

All deep penetration seismic surveys X 
Table 2-1. Summary of Applicable Existing Regulations, Survey Protocols, and Mitigation Measures (continued) 

P

Mitigation Measure Description Applicable Survey Types OG 

Guidance for Vessel Strike Avoidance 

Under both Alternatives A and B, all authorizations for shipboard surveys would include guidance for vessel strike avoidance. The guidance would be similar to NTL 2012-JOINTG01 (Vessel Strike Avoidance and Injured/Dead Protected Species Reporting), which 

incorporates NMFS “Vessel Strike Avoidance Measures and Reporting for Mariners” addressing protected species identification, vessel strike avoidance, and injured/dead 

protected species reporting. The guidance also incorporates elements of the NMFS Compliance Guide for the Right Whale Ship Strike Reduction Rule (50 CFR 224.105). 

All surveys involving ships (in transit and during data collection operations) 

X 

Guidance for Marine Debris Awareness 

Under both Alternatives A and B, all authorizations for shipboard surveys would include guidance for marine debris awareness. The guidance would be similar to NTL No. 2012-BSEE-G01 (Marine Trash and Debris Awareness and Elimination). The applicant would be 

required to ensure that its employees and contractors are made aware of the environmental 

and socioeconomic impacts associated with marine trash and debris and their responsibilities for ensuring that trash and debris are not discharged into the marine environment.

All vessel surveys X 

Avoidance and Reporting of Historic and Prehistoric sites 

Under both Alternatives A and B, all authorizations for G&G activities that involve seafloordisturbing activities would include requirements for operators to report suspected historic and 

prehistoric archaeological resources to the BOEM and to take precautions to protect the resource. BOEM also requires reporting and avoidance for any previously undiscovered suspected archaeological resource and precautions to protect the resource from operational activities while appropriate mitigation measures are developed. 

All surveys involving seafloor activities including coring, grab sampling, and placement of bottom cables, nodes, or buoys 

X 

Avoidance of Sensitive Benthic Communities 

Under both Alternatives A and B, all authorizations for seafloor-disturbing activities would be subject to restrictions to protect sensitive benthic communities (e.g., hard/live bottom areas, deepwater coral communities, and chemosynthetic communities), including requirements for mapping and avoidance, as well as pre-deployment photographic survey ofareas where bottom-founded instrumentation and appurtenances are to be deployed. 

All surveys involving seafloor activities including coring, grab sampling, and placement of bottom cables, nodes, or buoys 

X 

Guidance for Activities In or Near National Marine Sanctuaries 

Under both Alternatives A and B, all authorizations for G&G activities would include instructions to minimize impacts on NMS resources. Operators would be instructed to exercise caution to ensure that their activities do not endanger any other users of the Sanctuary. Additionally, if proposed activities involve seafloor disturbance near an NMS or moving the surface marker buoys for the Sanctuary, the operator would be required to contact the Sanctuary Manager for instructions. The BOEM would not authorize seafloor-disturbing activities within the boundaries of an NMS, and seafloor-disturbing activities proposed near the boundaries of an NMS would be assigned a setback distance as a condition of permit approval to be determined by BOEM in consultation with the Sanctuary Manager. 

All surveys X 

Guidance for Military and NASA Coordination 

Under both Alternatives A and B, all authorizations for permitted activities would include guidance for military and NASA coordination. The guidance would be similar to NTL No. 2009-G06 (Military Warning and Water Test Areas) (USDOI, MMS, 2009c). Vessel and aircraft operators would be required to establish and maintain early contact and coordination with the appropriate military command headquarters or NASA point of contact. 

All surveys X 

Abbreviations: AOI = Area of Interest; CFR = Code of Federal Regulations; HRG = high-resolution geophysical; MM = marine minerals; NT

Operators; OG = oil and gas; PAM = passive acoustic monitoring; RE = renewable energy; SMA = Seasonal Management Area. a The BOEM does not expect that airguns would be used in HRG surveys for renewable energy or marine minerals sites. However, the renewable 

possibility of a deep penetration seismic survey to evaluate formation suitability for carbon sequestration. 
Tables Tables-7 

Table 2-2 

 

Comparison of Impact Levels for Alternatives A, B, and C 

Alternativea

Resource and 

Impact-Producing Factor A B C 

Benthic Communities 

Active Acoustic Sound Sources 

Airguns Negligible Negligible N/A 

Electromechanical sources Negligible Negligible Negligible 

Trash and Debris Negligible Negligible Negligible 

Seafloor Disturbance Negligible-Minor Negligible-Minor Negligible 

Drilling Discharges Negligible Negligible N/A 

Accidental Fuel Spills Negligible Negligible Negligible 

Marine Mammals 

Active Acoustic Sound Sources 

Airguns Moderate Moderate N/A 

Electromechanical sources Minor Minor Minor 

Vessel and Equipment Noise Negligible-Minor Negligible-Minor Negligible-Minor 

Vessel Traffic Negligible Negligible Negligible 

Aircraft Traffic and Noise Negligible-Minor Negligible-Minor N/A

Trash and Debris Negligible Negligible Negligible 

Accidental Fuel Spills Negligible-Minor Negligible-Minor Negligible-Minor 

Sea Turtles 

Active Acoustic Sound Sources 

Airguns Negligible-Moderate Negligible-Minor N/A 

Electromechanical sources Negligible-Minor Negligible-Minor Negligible 

Vessel and Equipment Noise Negligible Negligible Negligible 

Vessel Traffic Negligible Negligible Negligible 

Aircraft Traffic and Noise Negligible Negligible N/A 

Trash and Debris Negligible Negligible Negligible 

Accidental Fuel Spills Negligible-Minor Negligible-Minor Negligible-Minor 

Marine and Coastal Birds 

Active Acoustic Sound Sources 

Airguns Negligible-Minor Negligible-Minor N/A 

Electromechanical sources Negligible Negligible Negligible 

Vessel and Equipment Noise Negligible-Minor Negligible-Minor Negligible 

Vessel Traffic Negligible-Minor Negligible-Minor Negligible 

Aircraft Traffic and Noise Negligible-Minor Negligible-Minor N/A 

Trash and Debris Negligible Negligible Negligible 

Accidental Fuel Spills Negligible-Moderate Negligible-Moderate Negligible-Moderate
Tables-8 Atlantic G&G Programmatic EIS 

Table 2-2 Comparison of Impact Levels for Alternatives A, B, and C (continued) 

Alternativea

Resource and 

Impact-Producing Factor A B C 

Fisheries Resources and EFH 

Active Acoustic Sound Sources 

Airguns Minor Minor N/A 

Electromechanical sources Minor Minor Negligible 

Vessel and Equipment Noise Minor Minor Negligible 

Seafloor Disturbance Negligible Negligible Negligible 

Drilling Discharges Negligible Negligible N/A 

Accidental Fuel Spills Minor Minor Minor 

Threatened and Endangered Fishes 

Active Acoustic Sound Sources 

Airguns Negligible-Minor Negligible-Minor N/A 

Electromechanical sources Negligible-Minor Negligible-Minor Negligible 

Vessel and Equipment Noise Negligible-Minor Negligible-Minor Negligible 

Vessel Traffic Negligible Negligible Negligible 

Trash and Debris Negligible Negligible Negligible 

Seafloor Disturbance Negligible Negligible Negligible 

Drilling Discharges Negligible Negligible N/A 

Accidental Fuel Spills Negligible Negligible Negligible 

Commercial Fisheries 

Active Acoustic Sound Sources 

Airguns Minor Minor N/A 

Electromechanical sources Minor Minor Negligible-Minor 

Vessel Traffic Minor Minor Negligible 

Vessel Exclusion Zones Minor Minor N/A 

Seafloor Disturbance Negligible Negligible Negligible 

Accidental Fuel Spills Negligible Negligible Negligible 

Recreational Fisheries 

Active Acoustic Sound Sources 

Airguns Negligible-Minor Negligible-Minor N/A 

Electromechanical sources Negligible-Minor Negligible-Minor Negligible 

Vessel Traffic Negligible-Minor Negligible-Minor Negligible 

Vessel Exclusion Zones Negligible Negligible N/A 

Accidental Fuel Spills Negligible Negligible Negligible 

Recreational Resources 

Vessel Exclusion Zones Negligible Negligible N/A 

Trash and Debris Negligible-Minor Negligible-Minor Negligible 

Accidental Fuel Spills Negligible-Minor Negligible-Minor Negligible-Minor 
Tables Tables-9 

Table 2-2 Comparison of Impact Levels for Alternatives A, B, and C (continued) 

Alternativea

Resource and 

Impact-Producing Factor A B C 

Archaeological Resources 

Seafloor Disturbance Negligible Negligible Negligible 

Drilling Discharges Negligible Negligible N/A 

Accidental Fuel Spills Negligible Negligible Negligible 

Marine Protected Areas (MPAs) 

Active Acoustic Sound Sources 

Airguns Negligible-Moderate Negligible-Minor N/A 

Electromechanical sources Negligible-Minor Negligible-Minor Negligible 

Trash and Debris Negligible Negligible Negligible 

Seafloor Disturbance Negligible Negligible Negligible 

Drilling Discharges Negligible Negligible N/A 

Accidental Fuel Spills Negligible-Minor Negligible-Minor Negligible-Minor 

Other Marine Uses 

Vessel Traffic Negligible-Minor Negligible-Minor Negligible-Minor 

Vessel Exclusion Zones Negligible-Minor Negligible-Minor N/A 

Aircraft Traffic and Noise Negligible Negligible N/A 

Seafloor Disturbance Negligible Negligible Negligible 

Accidental Fuel Spills Negligible Negligible Negligible 

Human Resources and Land Use 

Onshore Support Activity Negligible Negligible Negligible 

Accidental Fuel Spills Negligible Negligible Negligible 

Note: Impacts are categorized as Major, Moderate, Minor, or Negligible (see Chapter 4.1.2 for definitions). 

Shading indicates impacts that are reduced by at least one category relative to impacts of Alternative A. 

N/A = not applicable (the impact-producing factor would not occur under this Alternative). 

a

 Alternative A = The Proposed Action. Alternative B = Additional Time-Area Closures and Separation of 

Simultaneous Seismic Airgun Surveys. Alternative C = No Action for Oil and Gas, Status Quo for Renewable 

Energy and Marine Minerals G&G Activities. 
Tables-10 Atlantic G&G Programmatic EIS 

Table 3-1 

 

Types of G&G Activities Included in This Programmatic EIS 

Applicable Program Areas 

Survey Type Oil and 

Gas 

Renewable 

Energy 

Marine 

Minerals 

Purpose(s) 

Deep Penetration Seismic Surveys

2D Seismic Exploration Surveys X xa -- 

3D Seismic Exploration Surveys X xa -- 

Wide Azimuth Surveys X -- -- 

Nodes and Bottom Cable Surveys X -- -- 

Vertical Cable Surveys X -- -- 

4D (Time-Lapse) Surveys X -- -- 

Vertical Seismic Profile Surveys X -- -- 

Evaluate subsurface geological 

formations to assess potential 

hydrocarbon reservoirs and 

optimally site exploration and 

development wells. 4D surveys are 

used to monitor reservoirs over 

time during production. 

High-Resolution Geophysical Surveys

With single airgun as seismic source X -- -- 

With boomer or chirp subbottom profiler 

as seismic source -- X X 

Assess shallow hazards, 

archaeological resources, and 

benthic habitats 

Electromagnetic Surveys 

Controlled Source Electromagnetic 

Surveys X -- -- 

Magnetotelluric Surveys X -- -- 

Help distinguish economic 

hydrocarbon accumulations from 

other scenarios by using 

electromagnetic signals to develop 

a conductivity/resistivity profile of 

the seafloor. 

Deep Stratigraphic and Shallow Test Drilling

Continental Offshore Stratigraphic Test 

(COST) wells X -- -- 

Shallow test drilling X -- -- 

COST wells evaluate stratigraphy 

and hydrocarbon potential without 

drilling directly into oil and gas 

bearing strata. Shallow test drilling 

is conducted to place test 

equipment into a borehole to 

evaluate gas hydrates or other 

properties. 

Bottom Sampling

Cone Penetrometer Tests X X X 

Vibracoring X X X 

Geologic Coring X X X 

Grab Sampling X X X 

Collect surface and near-surface 

sediment samples to assess seafloor 

properties for siting structures such 

as platforms, pipelines, or cables. 

Remote Sensing

Gravity Surveys X -- -- 

Gravity Gradiometry X -- -- 

Marine Magnetic Surveys X -- -- 

Radar Imaging X -- -- 

Aeromagnetic Surveys X -- -- 

Gravity and magnetic surveys are 

used to assess structure and 

sedimentary properties of 

subsurface horizons. 

Radar imaging is used to detect oil 

slicks on the sea surface (indicative 

of seepage). Aeromagnetic surveys 

evaluate deep crustal structure, salt 

related structure, and 

intra-sedimentary anomalies. a The renewable energy scenario includes the possibility that a deep penetration (2D or 3D) seismic survey would be 

conducted to evaluate formation suitability for carbon sequestration. However, given the much greater number 

and extent of seismic surveys included in the oil and gas scenario, a single seismic survey for carbon sequestration 

is not analyzed separately in this Programmatic EIS. 
Tables Tables-11 

Table 3-2 

 

Program Area, G&G Activity, Permitting Authority, and Typical NEPA Action 

How Approved 

G&G Activity in Support of On 

Lease 

Off Lease 

and/or 

Third Party

Permitting Authority OCS Plan1 Permit 

Application 

Typical NEPA 

Action 

Oil and Gas 

Exploration (post lease) X 30 CFR Part 550 EP EA or EIS 

Development (post lease) X 30 CFR Part 550 DOCD or 

DPP EA or EIS 

Ancillary Activities (post 

lease) X 30 CFR Part 550 Conditional, Plan Revision Notification Conditional, EA 

Exploration (prelease) X 30 CFR Part 551 None X EA or EIS 

Scientific Research X 30 CFR Part 551 None X EA 

Renewable Energy 

Site Assessment X 30 CFR Part 585 SAP EA or EIS 

Renewable Energy Facility 

Development X 30 CFR Part 585 COP EA or EIS 

Other Activities X 30 CFR Part 585 GAP EA or EIS 

Marine Minerals 

Research and Prospecting X OCSLA Section 11 

30 CFR Part 5802 None 

Authorization 

or 

Notification 

EA or EIS

Leasing-Related Monitoring X 

OCSLA Section 8(k)

30 CFR Part 581-

5822 None None None3

1

 Plan types defined in Chapters 3.2.1 and 3.3.1. 2

 Applies to competitive leasing only, which this Agency has never done for marine minerals. 

3

 Addressed in NEPA document for prospecting. 
Table 3-3 Projected Levels of G&G Activities for Oil and Gas Exploration in the Mid-Atlantic and South Atlantic Planning Areas, 

Mid-Atlantic Planning Area South Atlantic Planning Are

Year 2D (km) 3D (blocks)a WAZ (blocks)b HRG (line km) VSP (line km) CSEM (line km) 2D (km) 3D (blocks)a WAZ (blocks)b HRG (line km) 

2012 0 0 0 0 0 0 0 0 0 0 2013 83,400 0 0 0 0 0 28,450 0 0 0 2014 160,950 0 0 0 0 0 56,900 0 0 0 2015 12,875 0 0 0 0 0 8,050 0 0 0 2016 64,375 400 0 0 0 3,220 48,300 300 0 0 2017 41,800 200 0 0 0 16,100 38,624 200 0 3,220 2018 16,100 200 100 3,220 0 32,200 32,200 200 100 32,200 2019 16,100 200 100 16,100 160 16,100 8,050 200 200 16,100 2020 800 300 200 64,375 320 32,200 800 300 200 40,250 

TOTAL 396,400 1,300 400 83,695 480 99,820 221,374 1,200 500 91,770 

Abbreviations: 2D = two-dimensional; 3D = three-dimensional; CSEM = controlled source electromagnetic; HRG = high-r

VSP = vertical seismic profile; WAZ = wide azimuth. a 3D surveys include ocean bottom cable and nodal surveys, vertical cable surveys, and 4D (time-lapse) surveys. Typically, on

(23.3 km2, 2,331 ha, or 5,760 ac). b WAZ estimates include coil shooting (exclusive to WesternGeco). 
Tables Tables-13

Table 3-4 

 

Projected Levels of Miscellaneous G&G Activities for Oil and Gas Exploration 

in the Mid-Atlantic and South Atlantic Planning Areas, 2012-2020 

Survey Type Number of Sampling Events Notes 

Magnetotelluric Surveys 0-2 surveys Hundreds to thousands of line km per survey, or 

<9 OCS blocks; 1-6 months per survey 

Gravity and Magnetic Surveys 

(remote sensing) 0-5 surveys 

Hundreds to thousands of line km per survey; 

4-12 months per survey. Data typically acquired 

during seismic surveys 

Aeromagnetic Surveys 

(remote sensing) 0-2 surveys Hundreds to thousands of line km per survey; 1-3 months per survey 

Continental Offshore 

Stratigraphic Test Wells 0-3 wells Penetration >150 m (500 ft). Requires an Environmental Assessment 

Shallow Test Drilling 0-5 wells Penetration <150 m (500 ft) 

Bottom Sampling 50-300 samples Mainly surficial and near-surface sediments; 

penetration <30 m (98 ft) 
Tables-14 Atlantic G&G Programmatic EIS 

Table 3-5 

 

Locations and Areas for Renewable Energy Site Characterization and Assessment Activities 

Offshore the Mid-Atlantic and South Atlantic Planning Areas 

State Areaa OCS Block 

Equivalents Description 

Mid-Atlantic Planning Area 

Delaware 

122 nmi2

103,323 ac 

41,813 ha 

18 

The Delaware area rests between the incoming and outgoing 

shipping routes for Delaware Bay, and is made up of 

11 whole OCS blocks and 16 partial blocks. The closest 

point to shore is approximately 10 nmi from Rehoboth 

Beach, DE. 

Maryland 

94 nmi2

 

79,706 ac 

32,256 ha 

14 

The Maryland area is defined as 9 whole OCS blocks and 

11 partial blocks. The western edge of the WEA is located 

approximately 10 nmi from the Ocean City, MD coast and 

the eastern edge is approximately 27 nmi from the Ocean 

City, MD, coast. 

Virginia 

164 nmi2

 

138,788 ac 

or 56,165 ha 

24 

The Virginia area consists of 22 whole OCS blocks and 

4 partial blocks. The western edge of the area is 

approximately 18 nmi from Virginia Beach, and the eastern 

edge is approximately 37 nmi from Virginia Beach. 

North Carolina 

510 nmi2

432,002 ac 

174,825 ha 

75 

In May 2011, North Carolina completed a screening exercise 

to yield a candidate area of 500 OCS lease blocks meeting 

their criteria for wind facility development. It was a 

screening exercise for potential environmental suitability 

and not an area proposed for wind development at this time. 

It is the expert judgment of BOEM staff that all 500 lease 

blocks would not be proposed for leasing, or actually leased 

to begin site assessment activities within the period covered 

by the Programmatic EIS. A more likely number is that 75 

lease blocks will eventually be assessed beginning in late 

2012 or early 2013. 

South Atlantic Planning Area 

South Carolina 

204 nmi2

172,800 ac 

69,930 ha 

30 Estimated 30 lease blocks. 

Georgia 

204 nmi2

172,800 ac 

69,930 ha 

30 Estimated 30 lease blocks. 

Florida 

204 nmi2

172,800 ac 

69,930 ha 

30 Estimated 30 lease blocks. 

Atlantic Wind Connection Transmission Cable 

New Jersey, 

Delaware, 

Maryland, 

Virginia 

0.23 nmi2

198 ac 

80 ha 

-- Proposed transmission cable extending from southern New 

Jersey to Virginia. 

a

 Areal extents for Delaware, Maryland, and Virginia are based on Wind Energy Areas designated offshore these 

states. For the other states, the area is based on the total number of OCS block equivalents, multiplied by an area 

of 2,331 ha (5,760 ac) per lease block. Calculations for the Atlantic Wind Connection transmission cable are 

based on a length of 1,320 km (820 mi) and a right-of-way width of 61 m (200 ft). 
Tables Tables-15

Table 3-6 

 

Projected Levels of G&G Activities for Renewable Energy Site Characterization and Assessment 

in the Mid-Atlantic and South Atlantic Planning Areas, 2012-2020 

Geotechnical Surveysb

Renewable 

Energy Area 

OCS 

Block 

Equivalents 

HRG Surveysa

(max km/hours) CPT 

(min-max) 

Geologic 

Coring 

(min-max) 

Grab 

Samples 

(min-max) 

Bottomfounded 

Monitoring 

Buoys 

(min-max) 

Timing 

Delaware 18 16,730/2,710 252–810 252–810 252–810 1–2 2012-2016

Maryland 14 13,030/2,110 196–630 196–630 196–630 1–6 2012-2017

Virginia 24 22,280/3,610 336–1,080 336–1,080 336–1,080 1–6 2012-2017

North Carolina 75 69,455/11,260 1,050–3,375 1,050–3,375 1,050–3,375 1–6 2012-2017

Mid-Atlantic 

Subtotal 131 121,495/19,690 1,834–5,895 1,834–5,895 1,834–5,895 4–20 2012-2017

South Carolina 30 27,830/4,510 420–1,350 420–1,350 420–1,350 1–6 2012-2017

Georgia 30 27,830/4,510 420–1,350 420–1,350 420–1,350 1–6 2013-2018

Florida 30 27,830/4,510 420–1,350 420–1,350 420–1,350 1–6 2013-2018

South Atlantic 

Subtotal 90 83,490/13,530 1,260–4,050 1,260–4,050 1,260–4,050 3–18 2012-2018

Atlantic 

Connection 

Transmission 

Cable 

-- 6,600/820 12–24 12-24 12–24 -- 2012-2020

TOTAL 221 211,585/34,040 3,106–9,969 3,106–9,969 3,106–9,969 7–38 2012-2020

a

 HRG survey effort per block was assumed to be 925 km (500 nmi), requiring 150 hours to complete. Added 

80 km (43 nmi) and 10 hours for surveying one transmission cable route for each state. For the Atlantic Wind 

Connection transmission cable, the proposed route length of 1,320 km (820 miles) was multiplied by 5 km per 

kilometer of route. 

b

 Geotechnical survey effort was estimated to be 14-45 sampling locations per block based on the potential range of 

wind turbine densities per block (assuming one sampling location per turbine location). For the Atlantic Wind 

Connection transmission cable, assumed up to 12 substations with one or two sampling locations per substation. 
Table 3-7 Projected Levels of High-Resolution Geophysical Surveys for OCS Sand Borrow Projects in the Mid-Atlantic and South Atlantic Planning Areas, 2012-2020 Prospecting HRGa (line km) Pre-Lease HRGa (line km) 

Year Project State Cycle Volume (cubic yd) Depth (m) Distance Offshore (km) (lower bound) (upper bound) (lower bound) (upper bound) 

Mid-Atlantic Planning Area Wallops Island VA 3,200,000 9-24 18-20 0 0 0 0 

2012-2013 Fort Story/Dam Neck VA 1,000,000 9-20 5 0 0 0 0 

Sandbridge VA 2,000,000 9-20 5 0 0 0 0 

Rehoboth/Dewey DE 360,000 9-20 5 26 642 47 235 

Bethany/S. Bethany DE 480,000 9-20 5 34 856 63 313 

Atlantic Coast of Maryland MD 800,000 12-16 12-16 0 0 104 522 

Wallops Island VA 806,000 9-24 18-20 0 0 0 0 

Sandbridge VA 2,000,000 9-20 5 0 0 0 0 

West Onslow/North Topsail NC 866,000 13-15 6-9 0 0 0 0 

2014-2016 Bogue Banks NC 500,000 13-15 3-5 0 0 65 327 

Rehoboth/Dewey DE 360,000 9-20 4.8 0 0 0 0 

Bethany/S. Bethany DE 480,000 9-20 4.8 0 0 0 0 

Atlantic Coast of Maryland MD 800,000 12-16 12-16 0 0 0 0 

Surf City/North Topsail NC 2,640,000 12-15 5-8 0 0 0 0 

2017-2020 Wrightsville Beach NC 800,000 N/A N/A 34 856 104 522 

South Atlantic Planning Area 2012-2013 Patrick Air Force Base FL 310,000 3-14 3-8 0 0 0 0 

Grand Strand SC 2,300,000 7-13 4-7 0 0 0 0 

Brevard County North Reach FL 516,000 3-14 3-8 0 0 0 0 

Brevard County Mid-Reach FL 900,000 3-15 3-8 0 0 0 0 

2014-2016 Brevard County South Reach FL 850,000 3-16 3-8 0 0 0 0 

Folly Beach SC 2,000,000 12-14 5 0 0 261 1306 

Duval County FL 1,500,000 14-19 10-11 0 0 0 0 

St. Johns FL N/A N/A 3-6 NA NA NA NA 

2017-2020 Flagler FL N/A N/A 3-5 NA NA NA NA 

TOTAL Mid-Atlantic Planning Area 17,092,000 94 2,354 383 1,919 

South Atlantic Planning Area 8,376,000 0 0 261 1,306 

Unknown Projects in Mid- and South Atlantic Planning Areas 2012-2020 8,000,000 N/A N/A 34 856 209 1,045 

Mid- and South Atlantic Planning Areas 33,468,000 128 3,210 853 4,270 

HRG = high-resolution geophysical; N/A = Not available. a Prospecting and prelease HRG involves the use of subbottom profiler, side-scan sonar, bathymetry (depth sounders), and magnetomeb On-lease typically involves only a bathymetry (depth sounders). 
Tables Tables-17 

Table 3-8 

 

Projected Levels of Geotechnical Surveys for OCS Sand Borrow Projects 

in the Mid-Atlantic and South Atlantic Planning Areas, 2012-2020 

Type of Geotechnical 

Sampling 

Number of 

Deployments 

Number of Samples 

Per Deployment Number of Samples 

Vibracoring 6-24 15-25 90-600 

Geologic coring 1-4 1-2 1-8 

Grab sampling 2-8 30-40 60-320 
Table 3-9 Scenario Elements for Proposed G&G Activities in the Mid-Atlantic and South Atlantic Planning Areas, 2012-2

Activity Type Purpose Number of Events or Level of Effort Primary Platform and Size Scale of Activity Penetration Depth Approximate Duration/ Event Shore Basea Service Vessel High

Sound 

Oil and Gas Exploration 2D Seismic Survey Identify geologic structure 1-10 1 ship, ~100 m 617,775 line km kms to 10s of kms 2-12 months 0 to 1 0 to 1 Airg

3D Seismic Survey Identify geologic structure 5-10 1-2 ships, ~100 m 2,500 OCS blocks kms to 10s of kms 4-12 months 0 to 1 0 to 1 Dual a

3D WAZ and 3D FAZ Coil Better define complex geologic structure 1-2 4 ships, ~100 m 900 line km kms to 10s of kms 1 year 0 to 2 1 to 2 4 x 

Vertical Seismic Profiling Calibrate seismic with known geology 3-8 1 ship, ~30 m 1,280 line km 100s to 1,000s of m 3-4 days 1 None Sing

High-Resolution Seismic Survey Shallow hazards assessment and archaeological determinations 10-20 1 ship, ~30 m 175,465 line km 10s to 100s of m 3 days – 1 week 1 None 

 1-2 a

 Boom

subbo

 Side-

 Mult

depth 

3D Controlled 

Source 

Electromagnetic 

Optimize 

reservoir 

production 

0-2 1 ship, ~20-100 m 119,760 km 3-5 km 1-6 months 0 to 1 0 to 1 N

Magnetotelluric 

Survey 

Optimize 

reservoir 

production 

0-2 1 ship, ~20-100 m 

100s to 1,000s 

of line kms; 

or ≤9 OCS 

blocks 

3-5 km 1-6 months 0 to 1 0 to 1 N

Gravity and 

Magnetic 

Passive 

measurement, 

gravity and 

magnetic fields 

0-5 Acquisition with seismic typical 100s to 1,000s of line kms kms to 10s of kms 4-12 months 0 to 1 0 to 1 N

Aeromagnetic 

Passive 

measurement, 

magnetic fields 

1-2 1 aircraft 100s to 1,000s of line kms kms to 10s of kms 1-3 months 0 to 1 0 N

COST Well 

Test drilling 

outside of lease 

program 

0-3 

well 

Platform or 

drillship, ~100 m

<1/16 OCS 

block ≥150 m 5-30 days 0 to 1 0 to 2 N

Shallow Test 

Drilling 

Test drilling 

outside of lease 

program 

0-5 

wells 

Platform or 

drillship, ~100 m

<1/16 OCS 

block <150 m 5-30 days 0 to 1 0 to 2 N

Bottom Sampling Extract sediment core 50-300 1 barge or ship, ~20 m <1/16 OCS block <300 m <3 days 0 to 1 None N
Table 3-9. Scenario Elements for Proposed G&G Activities in the Mid-Atlantic and South Atlantic Planning Areas, 2012-2020 (cont

Activity Type Purpose Number of Events or Level of Effort Primary Platform and Size Scale of Activity Penetration Depth Approximate Duration/ Event Shore Basea Service Vessel High

Sound 

Renewable Energy High-Resolution Geophysical Survey Shallow hazards assessment and archaeological determinations 1 or more surveys per state 1 ship, ~20-30 m Each survey 

≥1/16 OCS blockb

plus cable route to 

shore; Total 

211,585 line km 

(about 220 OCS 

blocks) 

Surficial to 

10s to 100s 

of meters 

3 days – 

1 weeks 1 None 

 Boom

subbprofi

 Side-

 Mult

depth 

Cone Penetrometer 

Test 

Measure sediment 

engineering 

properties 

2,712-8,374 1 barge or ship, ~20 m 

≥1/16 OCS 

block or along 

cable route to 

shore 

<10 m <3 days 1 None N

Geologic Coring Extract sediment core 2,712-8,374 1 barge or ship, ~20 m 

≥1/16 OCS 

block or along 

cable route to 

shore 

<300 m <3 days 1 None N

Grab Sampling Collect sediment and benthic fauna 2,712-8,374 1 barge or ship, ~20 m 

≥1/16 OCS lock 

or along cable 

route to shore 

<1 m <3 days 1 None N

Bottom-Founded 

Monitoring Buoy 

Measure ocean 

and 

meteorological 

conditions 

7-38 1 barge or ship, ~20 m 

≥1/16 OCS 

block Surficial <3 days 1 None N

2D or 3D Deep 

Penetration Seismic 

Evaluate formation 

for carbon 

sequestration 

0 to 1 survey 1 ship, ~100 m <1 OCS block km to 10s of km 1 - 30 days 1 0-2 Airg

or d

Marine Minerals 

High-Resolution 

Geophysical Survey 

Shallow hazards 

assessment and 

archaeological 

determinations 

10-40 surveys, 

9-21 wks 1 ship, ~30 m 

~1,904-12,090 

line kms; or 

1-4.5 OCS 

blocks 

10s to 100s 

of m 

3 days - 1 

weeks 1 None 

 Boom

subbprofi

 Side-

 Mult

depth 

Vibracoring Extract sediment core 6-24 events (90-600 cores) 1 barge or ship, ~20 m 

≥1/16 OCS 

block 10-15 m 3-5 days 1 None N

Geologic 

Coring 

Extract sediment 

core 

1-4 events 

(1-8 cores) 

1 barge or ship, 

~20 m 

≥1/16 OCS 

block <300 m <3 days 1 None N
Table 3-9. Scenario Elements for Proposed G&G Activities in the Mid-Atlantic and South Atlantic Planning Areas, 201

Activity Type Purpose Number of Events or Level of Effort Primary Platform and Size Scale of Activity Penetration Depth Approximate Duration/ Event Shore Basea Service Vessel High

Sound 

Grab Sampling Collect sediment and benthic fauna 2-8 events (60-320 grabs) 1 barge or ship, ~20 m 

≥1/16 OCS 

block <1 m <3 days 1 None N

Abbreviations: COST = Continental Offshore Stratigraphic Test; FAZ = Full Azimith Survey; NA = Not applicable; OCS = O

WAZ = Wide Azimith Survey. 

a Shore base is the point of deployment to return berth. b 1/16 of an OCS block (256 ac) is the smallest area considered for renewable energy leasing. All full-build out renewable energy proj

and South Atlantic Planning Areas are wind park facilities that would be considerably larger than 1/16 of an OCS block. The averag

be 

≤10 OCS blocks in size. 
Tables Tables-21

Table 3-10 

 

Impact-Producing Factors 

Program Area Impact-Producing Factor OG RE MM Survey Type(s) Brief Description 

Active Acoustic Sound Sources 

Airguns X -- -- Deep penetration seismic 

surveys and HRG surveys 

Underwater noise from 

compressed air release 

Electromechanical Sources X X X 

HRG surveys of renewable 

energy and marine mineral 

sites 

Underwater noise from 

subbottom profilers, side-scan 

sonar, and multi-beam depth 

sounders 

Vessel and Equipment Noise X X X 

All vessel surveys; drilling 

of COST wells and shallow 

test wells 

Underwater noise from vessel 

engines and equipment, and 

from drilling activities 

Vessel Traffic X X X All vessel surveys 

Vessel movements including 

survey lines and round trips to 

onshore base 

Aircraft Traffic and Noise X -- -- Aeromagnetic surveys Aircraft traffic, and noise from 

engines and propellers 

Vessel Exclusion Zones X -- -- 

Deep penetration seismic 

surveys with towed 

streamers 

Temporary exclusion zone 

around streamer arrays to 

avoid entanglement 

Vessel Waste Discharges X X X All vessel surveys Bilge, ballast, sanitary and 

domestic waste discharges 

Trash and Debris X X X All vessel surveys Accidental release of trash or 

debris into the ocean 

Seafloor Disturbance 

Bottom Sampling X X X Geotechnical sampling and 

testing 

Collection of vibracore, 

geologic core, and grab 

samples; CPT testing 

Cables, Nodes, Anchors X -- -- 

Certain deep penetration 

seismic surveys and CSEM 

and MT surveys 

Temporary placement of 

cables, nodes, sensors, or 

anchors on or in seafloor 

COST Wells and Shallow 

Test Drilling X -- -- Drilling of COST wells and shallow test wells 

Seafloor disturbance due to 

placement of well template, 

jetting of well, and anchoring 

of drilling rig 

Meteorological Buoys -- X -- Site characterization for 

renewable energy areas 

Temporary anchoring of 

meteorological buoys 

Drilling Discharges X -- -- Drilling of COST wells and 

shallow test wells 

Release of drilling fluids and 

cuttings at seafloor and from 

drilling rig 

Onshore Support Activities X X X All vessel surveys 

Routine use of existing 

shorebase facilities, including 

purchase of fuel, supplies and 

services 

Accidental Fuel Spills X X X All vessel surveys 

Potential for release of diesel 

or fuel oil from a vessel 

accident 

Abbreviations: CSEM = controlled source electromagnetic; COST = Continental Offshore Stratigraphic Test; 

CPT = cone penetrometer test; HRG = high-resolution geophysical; MM = marine minerals; 

MT = magnetotelluric; OG = oil and gas exploration; RE = renewable energy. 
Tables-22 Atlantic G&G Programmatic EIS 

Table 3-11 

 

Characteristics of Active Acoustic Sound Sources Included in the Proposed Action 

Source Usage Operating Frequencies 

Broadband 

Source Level 

(dB re 1 Pa at 1 m) 

Large Airgun Array 

(5,400 in2

) 

Deep penetration seismic 

surveys, oil and gas 

exploration (2D, 3D, WAZ, 

VSP, 4D, etc.) 

10-2,000 Hz 

(most energy 

at <200 Hz) 

230.7 

Small Airgun Array 

(90 in2

) 

HRG surveys, 

oil and gas exploration 

10-2,000 Hz 

(most energy 

at <200 Hz) 

210.3 

Side-scan Sonar HRG surveys, 

all program areas 

100 kHz, 

400 kHz 226 

Boomer Subbottom 

Profiler 

HRG surveys, 

all program areas 200-16,000 Hz 212 

Chirp Subbottom Profiler 

HRG surveys, 

all program areas 

3.5 kHz, 

12 kHz, 

200 kHz 

222 

Multi-beam Depth 

Sounder 

HRG surveys, 

all program areas 240 kHz 213 

Source: Appendix D. 
Table 4-1 Impact-Producing Factors for G&G Activities Survey Type OG RE MM 

Active Acoustic 

Sound Sources 

Vessel and 

Equipment Noise 

Vessel Traffic 

Aircraft Traffic 

and Noise 

Exclusion Zones 

Vessel Wastes 

Trash and Debris 

Seafloor Disturbance 

Deep-Penetration Seismic Surveys

2D Seismic Exploration Surveys X -- -- X X X -- X X X -- 3D Seismic Exploration Surveys X -- -- X X X -- X X X -- Wide Azimuth Surveys X -- -- X X X -- X X X -- Nodes and Bottom Cable Surveys X -- -- X X X -- X X X X Vertical Cable Surveys X -- -- X X X -- X X X X 4D (Time-Lapse) Surveys X -- -- X X X -- X X X X Vertical Seismic Profile Surveys X -- -- X X X -- X X X X 

High-Resolution Geophysical Surveys

For oil and gas exploration (airgun as seismic source) X -- -- X X X -- -- X X -- For renewable energy or marine minerals (boomer or chirp subbottom profiler as seismic source) -- X X -- X X -- -- X X -- 

Electromagnetic Surveys 

Controlled Source Electromagnetic Surveys X -- -- -- X X -- -- X X -- Magnetotelluric Surveys X -- -- -- X X -- -- X X -- 

Deep Stratigraphic and Shallow Test Drilling 

Continental Offshore Stratigraphic Test Wells X -- -- -- X X -- -- X X X Shallow Test Drilling X -- -- -- X X -- -- X X X 

Bottom Sampling 

Cone Penetrometer Tests X X X -- X X -- -- X X X Vibracoring X X X -- X X -- -- X X X Geologic Coring X X X -- X X -- -- X X X Grab Sampling X X X -- X X -- -- X X X 

Remote Sensing 

Gravity Surveys X -- -- -- X X -- -- X X -- Gravity Gradiometry X -- -- -- X X -- -- X X -- Marine Magnetic Surveys X -- -- -- X X -- -- X X -- Radar Imaging X -- -- -- -- -- -- -- -- -- -- Aeromagnetic Surveys X -- -- -- -- -- X -- -- -- -- 

Abbreviations: OG = oil and gas; RE = renewable energy; MM = marine minerals. 
Table 4-2 Preliminary Screening of Potential Impacts (Leopold Matrix) Impact-Producing Factor Resource 

Active Acoustic 

Sound Sources 

Vessel and 

Equipment Noise 

Vessel Traffic 

Aircraft Traffic 

and Noise 

Exclusion Zones 

Vessel Wastes 

Trash and Debris 

Seafloor Disturbance 

Drilling Discharges 

Benthic Communities 

 Soft Bottom X -- -- -- -- -- X X X  Hard/Live Bottom/Coral/ 

Chemosynthetic X -- -- -- -- -- X X X 

Marine Mammals X X X X -- -- X -- -- Sea Turtles X X X X -- -- X -- -- Marine and Coastal Birds X X X X -- -- X -- -- Fisheries Resources and Essential Fish Habitat X X -- -- -- -- X X Threatened and Endangered Fishes X X -- -- -- -- X X X Commercial Fisheries X -- X -- X -- -- X -- Recreational Fisheries X -- X -- X -- -- -- -- Recreational Resources -- -- -- -- X -- X -- -- Archaeological Resources -- -- -- -- -- -- -- X X Marine Protected Areas X -- -- -- -- -- X X X Other Marine Uses -- -- X X X -- -- X -- Human Resources and Land Use -- -- -- -- -- -- -- -- -- Geology/Sediments -- -- -- -- -- -- -- -- -- Air and Water Quality -- -- -- -- -- -- -- -- -- X = potential impact for analysis. - = no impact expected. 
Tables Tables-25

Table 4-3 

 

Sources for G&G Impact-Producing Factors 

Program Area Impact Producing Factors OG RE MM Sources Included in Proposed Action 

Active Acoustic Sound Sources 

Airguns X -- -- Seismic airgun surveys 

Electromechanical sources X X X HRG surveys 

Vessel and Equipment Noise X X X All shipboard surveys 

Vessel Traffic X X X All shipboard surveys 

Aircraft Traffic and Noise X -- -- Aeromagnetic surveys 

Exclusion Zones X -- -- Seismic airgun surveys using towed streamers 

Trash and Debris X X X All shipboard surveys 

Seafloor Disturbance X X X Bottom-founded activities – coring, equipment emplacement

Drilling Discharges X -- -- Drilling of COST wells and shallow test wells 

Onshore Support X X X All surveys 

Accidental Fuel Spills X X X All shipboard surveys 

Abbreviations: OG = oil and gas; RE = renewable energy; MM = marine minerals. 
Table 4-4 Marine Mammals Potentially Occurring in the Area of Interest 

Common Name Species Stock ESA/ Stock Status1 Occurrence Best Pop. Estimate2 Critical Habitat i

Area of Interest 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common Minke Whale Balaenoptera acutorostrata acutorostrata Canadian East Coast Rare 8,987 -- 

Sei Whale Balaenoptera borealis Nova Scotia E/S Rare 386 -- Bryde’s Whale Balaenoptera brydei N/A Rare N/A -- Blue Whale Balaenoptera musculus Western North Atlantic E/S Rare unknown -- Fin Whale Balaenoptera physalus Western North Atlantic E/S Regular 3,985 -- North Atlantic Right Whale Eubalaena glacialis Western Atlantic E/S Regular 361 Yes Humpback Whale Megaptera novaeangliae Gulf of Maine E/S Regular 847 -- 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked Common Dolphin Delphinus delphis Western North Atlantic Regular 120,743 -- Pygmy Killer Whale Feresa attenuata Western North Atlantic Rare unknown -- 

Short-Finned Pilot Whale Globicephala macrorhynchus Western North Atlantic Regular 24,674 -- Long-Finned Pilot Whale Globicephala melas Western North Atlantic Regular 12,619 -- Risso’s Dolphin Grampus griseus Western North Atlantic Regular 20,479 -- Northern Bottlenose Whale Hyperoodon ampullatus Western North Atlantic Rare unknown -- Pygmy Sperm Whale Kogia breviceps Western North Atlantic Regular 395 -- Dwarf Sperm Whale Kogia sima Western North Atlantic Regular 395 -- Atlantic White-sided Dolphin Lagenodelphis acutus Western North Atlantic Rare 63,368 -- Fraser's Dolphin Lagenodelphis hosei North Atlantic Rare unknown -- Sowerby’s Beaked Whale Mesoplodon bidens Western North Atlantic Regular 3,513 -- Blainville’s Beaked Whale Mesoplodon densirostris Western North Atlantic Regular 3,513 -- Gervais’ Beaked Whale Mesoplodon europaeus Western North Atlantic Regular 3,513 -- True’s Beaked Whale Mesoplodon mirus Western North Atlantic Regular 3,513 -- Killer Whale Orcinus orca Western North Atlantic Rare unknown -- Melon-Headed Whale Peponocephala electra Western North Atlantic Rare unknown -- Harbor Porpoise Phocoena phocoena Gulf of Maine/Bay of Fundy Rare 89,054 -- Sperm Whale Physeter macrocephalus North Atlantic E/S Regular 4,804 -- False Killer Whale Pseudorca crassidens N/A N/A unknown -- Pantropical Spotted Dolphin Stenella attenuata Western North Atlantic Regular 4,439 -- 
Table 4-4 Marine Mammals Potentially Occurring in the Area of Interest (continued) 

Common Name Species Stock ESA/ Stock Status1 Occurrence Best Pop. Estimate2 Critical Habitat i

Area of Interest 

Clymene Dolphin Stenella clymene Western North Atlantic Rare unknown -- Striped Dolphin Stenella coeruleoalba North Atlantic Regular 94,462 -- Atlantic Spotted Dolphin Stenella frontalis Western North Atlantic Regular 50,978 -- Spinner Dolphin Stenella longirostris Western North Atlantic Rare unknown -- Rough-Toothed Dolphin Steno bredanensis Western North Atlantic Rare unknown -- 

Western North Atlantic Offshore Regular 81,588 -- 

Bottlenose Dolphin Tursiops truncatus Coastal and estuarine stocks (12 stocks; see text) S Regular varies -- Cuvier’s Beaked Whale Ziphius cavirostris Western North Atlantic Regular 3,513 -- 

ORDER SIRENIA West Indian Manatee (Florida subspecies) Trichechus manatus latirostris Florida E/S Rare 3,802 Nearby (FL inlan

waters) 

ORDER CARNIVORA Suborder Pinnipedia Hooded Seal Cystophora cristata Western North Atlantic Rare unknown -- 

Gray Seal Halichoerus grypus Western North Atlantic Rare unknown -- Harbor Seal Phoca vitulina Western North Atlantic Rare unknown -- 

N/A = Not available. 1 ESA = Endangered Species Act; E = endangered; S = strategic stock. 2 Best population estimate “NBest” from Table 1 of the Waring et al. (2010) stock assessment report. 3 Functional marine mammal hearing groups and specific auditory ranges (Adapted from Southall et al., 2007). L = Low-Frequency 

M = Mid-Frequency Cetacean (150 Hz-160 kHz); H = High-Frequency Cetacean (200 Hz-180) kHz; P = Pinniped In Water (75 Hz-7

4 Manatee hearing is not addressed by Southall et al. (2007). Based on review of marine mammal hearing capabilities for this Program

manatee hearing is generally similar to that of phocid pinnipeds except at the lowest frequencies. 

Source: Waring et al. (2010). 
Tables-28 Atlantic G&G Programmatic EIS 

Table 4-5 

 

Designated U.S. and Canadian Seasonal Management Areas for the North Atlantic Right Whale 

Regional Area Individual Areas Concerns Period of Activity 

Cape Cod Bay Feeding Area January 1–May 15 

Off Race Point Feeding Area March 1–April 30 Northeast U.S. Seasonal 

Management Areas Great South Channel Feeding Area April 1–July 31 

Block Island Sound Migratory Route and 

Calving Grounds 

November 1–April 30 

Ports of New York/ 

New Jersey 

Entrance to Delaware Bay 

Entrance to Chesapeake Bay 

Ports of Morehead City and 

Beaufort, NC 

Mid-Atlantic U.S. Seasonal 

Management Areas 

Wilmington, NC to 

Brunswick, GA 

Southeast U.S. Seasonal 

Management Area Central GA to northeast FL Calving and Nursery Grounds November 15–April 15 

Grand Manan Basin 

Critical Habitat Area 

New Brunswick and 

Nova Scotia, Canada Feeding Area 

Roseway Basin Critical 

Habitat Area South of Nova Scotia, Canada Feeding Area June–December 

Table 4-6 

 

Existing and Proposed Injury and Behavior Exposure Criteria 

for Cetaceans and Pinnipeds Exposed to Pulsed Sounds 

Level A (Injury) Level B (Behavior) 

Group 

NMFS Criteria 

(Federal Register, 

2000): 

Sound Pressure Level 

(dB re 1 μPa rms) 

Southall et al. (2007) 

Criteria: 

Sound Exposure Level 

(dB re 1 μPa2

 s) 

Southall et al. (2007) 

Criteria: 

Single Pulse, Sound 

Pressure Level 

(dB re 1 μPa rms) 

NMFS Criteria 

(Federal Register, 

2000): 

Sound Pressure Level 

(dB re 1 μPa rms) 

Cetaceans 180 198 230 160 

Pinnipeds 190 186 218 160 

Note: Current regulatory thresholds are shaded. 
Tables Tables-29 

Table 4-7 

 

Functional Marine Mammal Hearing Groups, Associated Auditory Bandwidths, 

and Marine Mammal Species Present in the Area of Interest 

Functional Hearing Group Estimated Auditory 

Bandwidth 

Marine Mammal Species 

Present in the AOI 

Low-frequency cetaceans 7 Hz-22 kHz North Atlantic right whale; blue whale; fin whale; humpback 

whale; sei whale; Bryde’s whale; common minke whale 

Mid-frequency cetaceans 150 Hz-160 kHz 

Sperm whale; beaked whales; Stenella dolphins; bottlenose 

dolphin; killer whale; pygmy killer whale; false killer whale; 

Risso’s dolphin; short-finned and long-finned pilot whales; 

common dolphin; melon-headed whale; Atlantic white-sided 

dolphin; Fraser’s dolphin; rough-toothed dolphin 

High-frequency cetaceans 200 Hz-180 kHz Pygmy and dwarf sperm whales; harbor porpoise 

Pinnipeds in water 75 Hz-75 kHz Harbor, gray, and hooded seals 

Pinnipeds in air 75 Hz-30 kHz Harbor, gray, and hooded seals 

Abbreviaton: AOI = Area of Interest; Hz = hertz; kHz = kilohertz. 

Source: Southall et al., 2007. 
Tables-30 Atlantic G&G Programmatic EIS 

Table 4-8 

 

Summary of Radial Distances to the 160-dB and 180-dB (rms) Isopleths 

from a Single Pulse for Various Equipment 

180-dB Radius (m) 160-dB Radius (m) 

Equipment 

Number of 

Scenarios 

Modeled 

Pulse 

Duration 

Adjustment 

(dB) for 

Short Pulse 

Durationa

Calculated 

using Nominal 

Source Levelb

Recalculated 

for Short Pulse 

Durationa

Calculated 

using Nominal 

Source Levelb

Recalculated 

for Short Pulse 

Durationa

Large Airgun 

Array (5,400 in3

), 

2D and 3D 

Surveys 

35 >100 ms -- 799-2,109 -- 5,184-15,305 -- 

Small Airgun 

Array (90 in3

), 

Oil and Gas HRG 

Surveys 

35 >100 ms -- 76-186 -- 1,294-3,056 -- 

Boomer 14 180 μs -27.3 38-45 <5 1,054-2,138 16 

Side-Scan Sonar 14 20 ms -7.0 128-192 65-96 500-655 337-450 

Chirp Subbottom 

Profiler 14 64 ms -1.9 32-42 26-35 359-971 240-689 

Multibeam Depth 

Sounder 7 225 μs -26.5 27 <5 147-156 12 

a

 For sources with a pulse duration <100 ms, the nominal source level was adjusted by the amount indicated to 

produce a second, “recalculated” radius for both the 180-dB and 160-dB criteria. See Appendix D. b

 The value is the radius (Rmax) for the maximum received sound pressure level. See Appendix D. 

Source: Appendix D. 
Table 4-9 Annual Level A Take Estimates from Seismic Airgun Sources Using Southall et al. (2007) Criteria for Marine Mamm

during the Project Period (2012-2020) Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common minke whale 0.000 0.083 0.161 0.013 0.069 0.044 0.021 

Sei whale 0.000 0.208 0.402 0.032 0.176 0.113 0.057 Bryde's whale 0.000 0.632 1.237 0.128 0.721 0.526 0.359 Blue whale 0.000 0.831 1.622 0.164 0.915 0.663 0.439 Fin whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 North Atlantic right whale 0.000 0.036 0.071 0.008 0.045 0.034 0.024 Humpback whale 0.000 3.046 5.931 0.567 3.153 2.226 1.402 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked common dolphin 0.000 116.584 225.454 18.848 96.111 64.095 28.714 

Pygmy killer whale 0.000 0.161 0.312 0.027 0.175 0.113 0.081 Short-finned pilot whale 0.000 11.616 22.498 1.939 82.495 51.938 90.208 Long-finned pilot whale 0.000 59.577 117.528 13.877 79.694 61.037 45.681 Risso’s dolphin 0.000 370.550 731.439 87.140 501.580 385.115 290.103 Northern bottlenose whale 0.000 0.004 0.007 0.001 0.003 0.002 0.001 Pygmy sperm whale 0.000 0.000 0.000 0.000 0.081 0.041 0.080 Dwarf sperm whale 0.000 2.819 5.564 0.662 4.474 3.315 2.953 Atlantic white-sided dolphin 0.000 1.347 2.659 0.319 2.039 1.540 1.315 Fraser's dolphin 0.000 0.208 0.402 0.032 0.161 0.105 0.041 Sowerby's beaked whale 0.000 0.000 0.000 0.000 0.006 0.004 0.007 Blainville's beaked whale 0.000 1.459 2.816 0.225 1.126 0.731 0.282 Gervais' beaked whale 0.000 1.459 2.816 0.225 1.126 0.731 0.282 True's beaked whale 0.000 1.459 2.816 0.225 1.126 0.731 0.282 Killer whale 0.000 0.052 0.100 0.008 0.065 0.040 0.036 Melon-headed whale 0.000 0.161 0.312 0.027 0.175 0.113 0.081 Harbor porpoise 0.000 2.064 3.995 0.338 2.051 1.344 0.886 Sperm whale 0.000 0.095 0.184 0.015 0.076 0.050 0.021 False killer whale 0.000 0.155 0.300 0.026 0.236 0.151 0.158 Pantropical spotted dolphin 0.000 135.938 263.432 22.986 131.727 89.279 55.904 Clymene dolphin 0.000 64.945 125.855 10.982 62.933 42.653 26.708 Striped dolphin 0.000 527.416 1020.455 86.220 513.371 341.562 223.973 Atlantic spotted dolphin 0.000 771.308 1496.301 133.348 766.414 524.822 336.201 Spinner dolphin 0.000 0.611 1.184 0.103 0.592 0.401 0.251 Rough-toothed dolphin 0.000 0.000 0.000 0.000 0.036 0.023 0.043 Bottlenose dolphin 0.000 14.775 28.936 3.056 35.612 24.127 30.763 Cuvier's beaked whale 0.000 10.213 19.709 1.577 7.883 5.119 1.972 

ORDER SIRENIA West Indian manatee 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORDER CARNIVORA Suborder Pinnipedia Hooded seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Gray seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 
Table 4-10 Annual Level A Takes Estimates from Seismic Airgun Sources Using 180-dB Criteria for Marine Mammal Spec

during the Project Period (2012-2020) Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common minke whale 0.000 0.342 0.666 0.064 0.380 0.266 0.187 

Sei whale 0.000 1.965 3.855 0.417 2.564 1.880 1.476 Bryde's whale 0.000 1.948 3.820 0.412 2.535 1.857 1.457 Blue whale 0.000 2.182 4.274 0.451 2.753 2.000 1.539 Fin whale 0.000 4.400 8.638 0.949 5.896 4.342 3.474 North Atlantic right whale 0.000 1.162 2.290 0.269 1.883 1.395 1.294 Humpback whale 0.000 5.897 11.542 1.207 7.332 5.314 4.043 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked common dolphin 0.000 3121.383 6146.553 706.842 4436.718 3316.557 2733.398 

Pygmy killer whale 0.000 2.253 4.410 0.462 2.807 2.037 1.549 Short-finned pilot whale 0.000 2354.300 4631.133 524.156 3290.543 2446.116 2004.600 Long-finned pilot whale 0.000 297.400 582.360 61.349 376.210 273.181 211.129 Risso’s dolphin 0.000 1619.672 3180.466 350.367 2173.422 1603.231 1282.343 Northern bottlenose whale 0.000 0.127 0.250 0.029 0.179 0.134 0.110 Pygmy sperm whale 0.000 2.371 4.592 0.397 2.216 1.482 0.851 Dwarf sperm whale 0.000 14.844 29.005 2.947 17.492 12.581 9.146 Atlantic white-sided dolphin 0.000 4.668 9.152 0.985 5.987 4.389 3.388 Fraser's dolphin 0.000 0.242 0.468 0.039 0.218 0.143 0.078 Sowerby's beaked whale 0.000 0.203 0.397 0.040 0.242 0.174 0.128 Blainville's beaked whale 0.000 39.568 77.313 7.855 47.099 33.810 24.904 Gervais' beaked whale 0.000 39.568 77.313 7.855 47.099 33.810 24.904 True's beaked whale 0.000 39.568 77.313 7.855 47.099 33.810 24.904 Killer whale 0.000 1.965 3.843 0.396 2.393 1.727 1.293 Melon-headed whale 0.000 2.523 4.942 0.525 3.215 2.342 1.814 Harbor porpoise 0.000 7.054 13.798 1.428 8.705 6.283 4.777 Sperm whale 0.000 158.828 309.723 30.401 179.051 126.956 89.342 False killer whale 0.000 2.801 5.491 0.590 3.635 2.658 2.085 Pantropical spotted dolphin 0.000 446.741 876.082 94.513 580.242 425.213 332.719 Clymene dolphin 0.000 207.184 406.191 43.634 267.556 195.783 152.671 Striped dolphin 0.000 2038.848 3993.224 422.056 2575.257 1873.787 1441.135 Atlantic spotted dolphin 0.000 2978.964 5847.582 640.637 3949.211 2909.316 2303.489 Spinner dolphin 0.000 1.949 3.821 0.410 2.517 1.842 1.436 Rough-toothed dolphin 0.000 13.755 26.888 2.752 16.672 11.986 8.985 Bottlenose dolphin 0.000 5977.039 11748.210 1313.855 8207.035 6079.369 4930.570 Cuvier's beaked whale 0.000 276.973 541.189 54.986 329.696 236.673 174.331 

ORDER SIRENIA West Indian manatee 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORDER CARNIVORA Suborder Pinnipedia Hooded seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Gray seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 
Table 4-11 Annual Level B Take Estimates (160-dB criteria) from Airgun Surveys for Marine Mammal Species during the Project Period (2012-2020) Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common minke whale 0.000 33.522 65.282 6.257 37.268 26.060 18.319 

Sei whale 0.000 192.625 377.801 40.850 251.322 184.255 144.677 Bryde's whale 0.000 190.896 374.359 40.389 248.492 182.040 142.818 Blue whale 0.000 213.901 418.875 44.161 269.778 196.066 150.850 Fin whale 0.000 431.204 846.583 93.001 577.905 425.583 340.531 North Atlantic right whale 0.000 240.877 475.584 56.846 361.004 272.896 230.884 Humpback whale 0.000 577.964 1131.230 118.264 718.609 520.862 396.288 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked common dolphin 0.000 305926.755 602423.698 69277.598 434842.769 325055.721 267900.300 

Pygmy killer whale 0.000 220.776 432.193 45.316 275.090 199.618 151.862 Short-finned pilot whale 0.000 230744.930 453897.344 51372.535 322506.126 239743.839 196470.811 Long-finned pilot whale 0.000 29148.152 57077.138 6012.771 36872.388 26774.497 20692.778 Risso’s dolphin 0.000 158744.009 311717.478 34339.430 213017.091 157132.663 125682.450 Northern bottlenose whale 0.000 12.462 24.544 2.829 17.568 13.169 10.733 Pygmy sperm whale 0.000 232.353 450.073 38.920 217.178 145.240 83.426 Dwarf sperm whale 0.000 1454.885 2842.740 288.795 1714.399 1233.034 896.367 Atlantic white-sided dolphin 0.000 457.481 896.987 96.497 586.754 430.117 332.072 Fraser's dolphin 0.000 23.717 45.882 3.865 21.337 14.063 7.641 Sowerby's beaked whale 0.000 19.910 38.905 3.957 23.674 17.008 12.499 Blainville's beaked whale 0.000 3878.016 7577.415 769.884 4616.211 3313.759 2440.889 Gervais' beaked whale 0.000 3878.016 7577.415 769.884 4616.211 3313.759 2440.889 True's beaked whale 0.000 3878.016 7577.415 769.884 4616.211 3313.759 2440.889 Killer whale 0.000 192.589 376.649 38.861 234.535 169.229 126.733 Melon-headed whale 0.000 247.240 484.381 51.446 315.137 229.581 177.832 Harbor porpoise 0.000 691.367 1352.385 139.995 853.177 615.792 468.191 Sperm whale 0.000 15566.706 30355.996 2979.611 17548.740 12442.986 8756.403 False killer whale 0.000 274.527 538.213 57.806 356.282 260.465 204.367 Pantropical spotted dolphin 0.000 43785.058 85864.840 9263.266 56869.492 41675.091 32609.770 Clymene dolphin 0.000 20306.091 39810.739 4276.589 26223.212 19188.734 14963.300 Striped dolphin 0.000 199827.536 391375.882 41365.683 252400.939 183649.880 141245.653 Atlantic spotted dolphin 0.000 291968.246 573121.475 62788.875 387062.188 285142.042 225764.925 Spinner dolphin 0.000 191.026 374.513 40.231 246.691 180.515 140.765 Rough-toothed dolphin 0.000 1348.103 2635.268 269.746 1633.987 1174.707 880.655 Bottlenose dolphin 0.000 585809.587 1151442.029 128770.944 804371.539 595838.922 483245.127 Cuvier's beaked whale 0.000 27146.110 53041.902 5389.186 32313.477 23196.314 17086.222 

ORDER SIRENIA West Indian manatee 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORDER CARNIVORA Suborder Pinnipedia Hooded seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Gray seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 
Table 4-12 Annual Level A Take Estimates from All Non-Airgun High-Resolution Geophysical Surveys Using Southall et al. (200

for Marine Mammal Species during the Project Period (2012-2020) Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common minke whale 0.0003 0.0004 0.0004 0.0004 0.0004 0.0003 0.0000 

Sei whale 0.0020 0.0024 0.0024 0.0024 0.0024 0.0021 0.0004 Bryde's whale 0.0023 0.0030 0.0030 0.0030 0.0030 0.0027 0.0007 Blue whale 0.0002 0.0005 0.0005 0.0005 0.0005 0.0005 0.0003 Fin whale 0.0155 0.0208 0.0208 0.0208 0.0208 0.0185 0.0053 North Atlantic right whale 0.0021 0.0026 0.0026 0.0026 0.0026 0.0022 0.0005 Humpback whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked common dolphin 4.0936 5.2235 5.2235 5.2235 5.2235 4.5460 1.1299 

Pygmy killer whale 0.0004 0.0010 0.0010 0.0010 0.0010 0.0009 0.0006 Short-finned pilot whale 0.0053 0.0106 0.0106 0.0106 0.0106 0.0106 0.0053 Long-finned pilot whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Risso’s dolphin 1.8630 2.2287 2.2287 2.2287 2.2287 2.0205 0.3658 Northern bottlenose whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Pygmy sperm whale 0.0048 0.0064 0.0064 0.0064 0.0064 0.0059 0.0016 Dwarf sperm whale 0.0145 0.0192 0.0192 0.0192 0.0192 0.0178 0.0047 Atlantic white-sided dolphin 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Fraser's dolphin 0.0001 0.0003 0.0004 0.0004 0.0004 0.0003 0.0003 Sowerby's beaked whale 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0000 Blainville's beaked whale 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0000 Gervais' beaked whale 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0000 True's beaked whale 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0000 Killer whale 0.0025 0.0061 0.0061 0.0061 0.0061 0.0058 0.0036 Melon-headed whale 0.0001 0.0004 0.0004 0.0004 0.0004 0.0003 0.0003 Harbor porpoise 0.0005 0.0007 0.0007 0.0007 0.0007 0.0006 0.0002 Sperm whale 0.0008 0.0009 0.0009 0.0009 0.0009 0.0008 0.0001 False killer whale 0.0001 0.0004 0.0004 0.0004 0.0004 0.0003 0.0003 Pantropical spotted dolphin 0.4477 0.5868 0.6200 0.6200 0.6200 0.5432 0.1677 Clymene dolphin 0.2139 0.2803 0.2962 0.2962 0.2962 0.2595 0.0801 Striped dolphin 0.5954 0.7674 0.8121 0.8121 0.8121 0.7114 0.2107 Atlantic spotted dolphin 5.3991 6.9574 7.3614 7.3614 7.3614 6.4414 1.8980 Spinner dolphin 0.0020 0.0026 0.0028 0.0028 0.0028 0.0024 0.0008 Rough-toothed dolphin 0.0099 0.0145 0.0145 0.0145 0.0145 0.0134 0.0047 Bottlenose dolphin 1.2977 2.1422 2.3608 2.3608 2.3608 1.9922 1.0400 Cuvier's beaked whale 0.0013 0.0015 0.0015 0.0015 0.0015 0.0013 0.0003 

ORDER SIRENIA West Indian manatee 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 ORDER CARNIVORA Suborder Pinnipedia Hooded seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 

Gray seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Harbor seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 
Table 4-13 Annual Level A Take Estimates from All Non-Airgun High-Resolution Geophysical Surveys Using 180-dB Crit

for Marine Mammal Species during the Project Period (2012-2020) Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common minke whale 0.0002 0.0003 0.0003 0.0003 0.0003 0.0003 0.0002 

Sei whale 0.0004 0.0005 0.0005 0.0005 0.0005 0.0006 0.0012 Bryde's whale 0.0004 0.0005 0.0005 0.0005 0.0005 0.0006 0.0012 Blue whale 0.0007 0.0010 0.0011 0.0011 0.0011 0.0011 0.0015 Fin whale 0.0012 0.0016 0.0017 0.0017 0.0017 0.0018 0.0031 North Atlantic right whale 0.0020 0.0025 0.0025 0.0025 0.0025 0.0027 0.0051 Humpback whale 0.0025 0.0034 0.0035 0.0035 0.0035 0.0034 0.0037 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked common dolphin 1.2187 1.4589 1.4946 1.4946 1.4946 1.5087 2.0876 

Pygmy killer whale 0.0004 0.0005 0.0005 0.0005 0.0005 0.0006 0.0011 Short-finned pilot whale 0.0132 0.0166 0.0171 0.0171 0.0171 0.1358 1.2475 Long-finned pilot whale 0.0027 0.0033 0.0033 0.0033 0.0033 0.0153 0.1295 Risso’s dolphin 0.0913 0.1118 0.1118 0.1118 0.1118 0.1826 0.8666 Northern bottlenose whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0001 Pygmy sperm whale 0.0011 0.0015 0.0015 0.0015 0.0015 0.0014 0.0007 Dwarf sperm whale 0.0034 0.0046 0.0046 0.0046 0.0046 0.0046 0.0057 Atlantic white-sided dolphin 0.0000 0.0001 0.0001 0.0001 0.0001 0.0002 0.0017 Fraser's dolphin 0.0004 0.0006 0.0007 0.0007 0.0007 0.0006 0.0003 Sowerby's beaked whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0001 Blainville's beaked whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0013 0.0134 Gervais' beaked whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0013 0.0134 True's beaked whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0013 0.0134 Killer whale 0.0005 0.0007 0.0007 0.0007 0.0007 0.0007 0.0010 Melon-headed whale 0.0004 0.0005 0.0005 0.0005 0.0005 0.0006 0.0014 Harbor porpoise 0.0016 0.0018 0.0018 0.0018 0.0018 0.0019 0.0031 Sperm whale 0.0002 0.0002 0.0002 0.0002 0.0002 0.0041 0.0430 False killer whale 0.0004 0.0006 0.0006 0.0006 0.0006 0.0007 0.0016 Pantropical spotted dolphin 0.3036 0.4453 0.4509 0.4509 0.4509 0.4381 0.3559 Clymene dolphin 0.1450 0.2127 0.2154 0.2154 0.2154 0.2088 0.1643 Striped dolphin 0.3964 0.5755 0.5831 0.5831 0.5831 0.6088 0.9086 Atlantic spotted dolphin 3.4607 4.9269 4.9955 4.9955 4.9955 4.7511 3.0827 Spinner dolphin 0.0013 0.0019 0.0020 0.0020 0.0020 0.0019 0.0015 Rough-toothed dolphin 0.0057 0.0074 0.0075 0.0075 0.0075 0.0073 0.0080 Bottlenose dolphin 0.9382 1.4056 1.4650 1.4650 1.4650 1.6672 3.8323 Cuvier's beaked whale 0.0002 0.0002 0.0002 0.0002 0.0002 0.0090 0.0939 

ORDER SIRENIA West Indian manatee 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 ORDER CARNIVORA Suborder Pinnipedia Hooded seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 

Gray seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Harbor seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 
Table 4-14 Annual Level B Take Estimates from All Non-Airgun High-Resolution Geophysical Surveys Using 160-dB Crit

for Marine Mammal Species during the Project Period (2012-2020) Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common minke whale 0.0225 0.0287 0.0300 0.0300 0.0300 0.0282 0.0200 

Sei whale 0.0358 0.0476 0.0511 0.0511 0.0511 0.0557 0.1152 Bryde's whale 0.0355 0.0470 0.0505 0.0505 0.0505 0.0553 0.1169 Blue whale 0.0659 0.0980 0.1037 0.1037 0.1037 0.1048 0.1448 Fin whale 0.1153 0.1598 0.1665 0.1665 0.1665 0.1722 0.3083 North Atlantic right whale 0.1945 0.2461 0.2491 0.2491 0.2491 0.2690 0.5016 Humpback whale 0.2454 0.3285 0.3444 0.3444 0.3444 0.3313 0.3597 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked common dolphin 119.4440 142.9833 146.4839 146.4839 146.4839 147.8699 204.6009 

Pygmy killer whale 0.0345 0.0494 0.0494 0.0494 0.0494 0.0549 0.1097 Short-finned pilot whale 1.2920 1.6287 1.6711 1.6711 1.6711 13.3054 122.2637 Long-finned pilot whale 0.2621 0.3201 0.3267 0.3267 0.3267 1.4975 12.6893 Risso’s dolphin 8.9444 10.9577 10.9577 10.9577 10.9577 17.8981 84.9354 Northern bottlenose whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0006 0.0063 Pygmy sperm whale 0.1119 0.1503 0.1503 0.1503 0.1503 0.1410 0.0732 Dwarf sperm whale 0.3358 0.4508 0.4508 0.4508 0.4508 0.4557 0.5592 Atlantic white-sided dolphin 0.0027 0.0055 0.0055 0.0055 0.0055 0.0208 0.1680 Fraser's dolphin 0.0345 0.0568 0.0637 0.0637 0.0637 0.0575 0.0304 Sowerby's beaked whale 0.0023 0.0026 0.0026 0.0026 0.0026 0.0030 0.0073 Blainville's beaked whale 0.0023 0.0026 0.0026 0.0026 0.0026 0.1259 1.3153 Gervais' beaked whale 0.0023 0.0026 0.0026 0.0026 0.0026 0.1259 1.3153 True's beaked whale 0.0026 0.0032 0.0032 0.0032 0.0032 0.1265 1.3156 Killer whale 0.0509 0.0642 0.0678 0.0678 0.0678 0.0680 0.0952 Melon-headed whale 0.0361 0.0525 0.0525 0.0525 0.0525 0.0604 0.1362 Harbor porpoise 0.1543 0.1717 0.1812 0.1812 0.1812 0.1894 0.2990 Sperm whale 0.0182 0.0215 0.0215 0.0215 0.0215 0.4051 4.2127 False killer whale 0.0389 0.0582 0.0582 0.0582 0.0582 0.0674 0.1524 Pantropical spotted dolphin 29.7529 43.6445 44.1968 44.1968 44.1968 42.9366 34.8805 Clymene dolphin 14.2145 20.8513 21.1152 21.1152 21.1152 20.4600 16.1068 Striped dolphin 38.8529 56.4013 57.1529 57.1529 57.1529 59.6638 89.0555 Atlantic spotted dolphin 339.1818 482.8880 489.6133 489.6133 489.6133 465.6510 302.1377 Spinner dolphin 0.1306 0.1899 0.1924 0.1924 0.1924 0.1862 0.1484 Rough-toothed dolphin 0.5554 0.7281 0.7355 0.7355 0.7355 0.7138 0.7853 Bottlenose dolphin 91.9501 137.7600 143.5851 143.5851 143.5851 163.3981 375.6071 Cuvier's beaked whale 0.0158 0.0181 0.0181 0.0181 0.0181 0.8810 9.2072 

ORDER SIRENIA West Indian manatee 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 ORDER CARNIVORA Suborder Pinnipedia Hooded seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 

Gray seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Harbor seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 
Table 4-15 Sea Turtles Occurring in the Area of Interest Scientific Name Common Name Status1 Occurrence in Area of Interest Life Stage Primary Nesting Sites States with Nesting Reported in Area of Interest 

Caretta caretta Loggerhead turtle T2 DE–FL All Florida beaches: Brevard, Indian River, St. Lucie, Martin, Palm Beach, and Broward Counties VA, NC, SC, GA, FL PenChelonia mydas Green turtle E, T3 DE–FL All Florida beaches: Brevard, Indian River, St. Lucie, Martin, Palm Beach, and Broward Counties NC, SC, GA, FL CulEretmochelys imbricata Hawksbill turtle E DE–FL (uncommon north of FL) All Mexican beaches: Yucatán Peninsula; Caribbean Beaches: Puerto Rico [Culebra, Mona, and Vieques Islands], Barbados -- Mo

CulRicCulResPlaywatislaMo

Lepidochelys kempii Kemp’s ridley turtle E DE–FL Juveniles and Adults Mexican beaches: Tamaulipas and Veracruz NC, SC, FL PenDermochelys coriacea Leatherback turtle E DE–FL All Florida beaches (southeast coast) NC, SC, GA, FL U.S

of lSanSt. adja

1 Status: E = endangered (E); T = threatened. 2 The loggerhead turtle is currently classified as threatened throughout its range. In March 2010, NMFS and USFWS proposed to l

Ocean population of loggerhead turtles as endangered (Federal Register, 2010g). 3 The green turtle is threatened, except for the Florida breeding population, which is endangered (USDOC, NMFS, 2011g). 
Table 4-16 Families of Seabirds, Waterfowl, and Shorebirds Occurring in the Area of Interest Order Family General Ecology General Distribut

SEABIRDS Laridae (Gulls and terns) Primarily inhabit coastal or inshore waters. Conspicuous and gregarious in nature. Nest colonially on the ground. Most feed on small fishes with some foraging on insects and crabs. Terns typically forage by hovering above the water’s surface and plunge-diving head-first into the water from flight. Gulls seldom dive and prefer open areas. Highly adaptable. Found predominantly along t

in both populated and open a

northern Canada, and northerspecies migrating south to M

Rhyncopidae (Skimmers) Primarily inhabit coastal and inshore waters. Nest colonially on sandy beaches. Forages for small fishes mainly at night, flying over shallow water with their elongated lower mandible below the water surface. Year-round coastal distributiStercorariidae (Skuas and jaegers) Primarily oceanic, generally coming to land only to nest. Commonly acquire food by kleptoparasitism of other seabird species. Predatory when on nesting grounds. Migratory species, wintering 

portion of the AOI and movinest during the summer. Charadriiformes Alcidae (Puffins, murres, murrelets, and auklets) Oceanic species that come to land only to nest. Most nest colonially in crevices or burrows. All use their wings for underwater propulsion to pursue prey. Specialized bill shapes relate to feeding habits and prey types. Occur year-round in arctic anhabitats. In summer months, coastal nesting locations. In occur in oceanic waters, and southward into temperate wa

Gaviiformes Gaviidae (Loons) Medium to large birds that capture prey (fishes, crustaceans, and other aquatic organisms) by diving and pursuing underwater. Habitat includes tundra lakes and ponds in summer and coastal waters in winter. Nest on banks of ponds or lakes and winter on the open water. Holarctic in the summer in fr

migratory to more marine arewinter. Pelicanidae (Pelicans) Very large, social water birds that swim buoyantly and feed predominantly on fishes and crustaceans in primarily shallow estuarine waters, occasionally up to 40 miles from shore. Plunges bill-first into the water while fishing and often flies just above the water surface looking for prey. Nesting occurs usually on coastal islands, on the ground, or in small bushes and trees. Found in freshwater and mar

Breeding range extends along from Maryland south to Florrange includes Florida and thactivities extremely sensitive 

Phaethontidae (Tropicbirds) A mainly pelagic, highly aerial, solitary seabird found far offshore over and resting on warm water. Feed by plunge-diving. Nests in small to large colonies on tropical islands in rocky crevices, holes, or caves. Distributed in tropical and su

Occasionally found within ththe south Atlantic coast. Bre

Phalacrocoracidae (Cormorants) Large, gregarious water birds found in coastal bays, marine islands, and seacoasts usually within sight of land. Some species are found along rocky shores, while other are found in open water. Eats mostly schooling fishes by diving. Migratory and dispersive. Fo

tropical marine coasts. Cosmcoastal populations migrate snonbreeding season and usua

Sulidae (Gannets and boobies) Gregarious and colonial breeders in marine environment. Fish by plunging from air for fishes and squids. Boobies land-roost and gannets rest on open ocean. Nests in colonies on islands and rock stacks. Tropical, subtropical, and tem

with some found well offshoto shore. Pelicaniformes Fregatidae (Frigatebirds) Found in offshore and coastal waters. Feeding habits are pelagic and include snatching prey from the sea surface or beach, or in some cases One species (magnificent frig

ma

gnificens]) occurs within t
Table 4-16 Families of Seabirds, Waterfowl, and Shorebirds Occurring in the Area of Interest (continued) Order Family General Ecology General Distribut

by robbing other seabirds of their catch (kleptoparasitism). in the tropical Atlantic. Podicipediformes Podicipedidae (Grebes) Found in ponds, lakes, salt bays, and nearshore habitats. Feed by diving. Spend virtually all their time in the water and are clumsy on land. Cosmopolitan. Migrate from 

temperate nearshore areas. B

Hydrobatidae (Storm-petrels) Medium to large seabirds found over the open ocean and come to land only for nesting. Colonial breeders. Feed on plankton, crustaceans, and small fishes. Nest on sea islands. Breed November–May in the 

transequatorial migrants offsAtlantic. Procellariiformes Procellariidae (Petrels and shearwaters) Highly pelagic and return to land only for breeding. Feed on fishes, squids, and crustaceans. Colonial breeders on marine islands. Transequatorial. Most breed and migrate south in summer One species breeds in New Znorth to northern Atlantic. WATERFOWL Anatidae (Aythyinae) (Diving Ducks) Mainly in freshwater and estuarine environments, but species such as the greater scaup become marine during the winter. Breed in marshes. All dive for food including aquatic vegetation, mollusks, and crustaceans. Arctic, circumpolar during neinto temperate areas in wintewaters, estuaries and bays, an

Anseriformes Anatidae (Merginae) (Sea Ducks) Found in marine environment along seacoast. Breed in marshes. All dive for food including mollusks and crustaceans. Arctic, circumpolar during n

migrate into subarctic and nowinter. Frequent coastal watpack ice. SHOREBIRDS Charadriidae (Plovers) Wading birds found along mud flats, shores, and beaches that feed on small marine life, insects, and some vegetable matter. Nest singly or in loose colonies. Arctic, circumpolar. Winter South America, migrating alo

Haematopodidae (Oystercatchers) Large wading birds found along the coastal shores and tidal flats. Feed on mollusks, crabs, and marine worms. Distribution from Cape Cod 

Argentina. Recurvirostridae (Stilts and avocets) Slim wading birds found along beaches and mud flats. Feed on insects, crustaceans, and other aquatic organisms. Typically nest on open flats or areas with scattered tufts of grass on islands. Breed in southwest Canada amigration to southern U.S. to 

Charadriiformes Scolopacidae (Sandpipers, snipes, phalaropes, and allies) Small to medium sized wading birds found along mud flats, tidal flats, shores, beaches, and salt marshes. Red and red-necked phalaropes occur in small groups along weed lines on the open ocean. Feed on insects, crustaceans, mollusks, and worms. Cosmopolitan. Migrate alon

North America south as far aAmerica. Sources: Peterson, 1980; Harrison, 1983, 1987; Sibley, 2000; Morrison et al., 2001a; NatureServe, InfoNatura, 2010. 
Table 4-17 Important Bird Areas within Offshore, Nearshore, and Coastal Habitats Within and Adjacent to the Area of Inte

IBA Site State Latitude Longitude Habitat Resour

Assateague Island MD 38.62° 75.94° Barrier Island Shorebirds, SeabChesapeake Bay Islands VA 37.84° 75.99° Coastal Waterfowl, SeabBarrier Island/Lagoon System VA 37.53° 75.68° Barrier Island/Coastal Shorebirds, SeabBack Bay VA 36.62° 75.94° Coastal Shorebirds Outer Banks Inshore Ocean NC 35.90° 75.58° Offshore Seabirds, WaterfOuter Continental Shelf NC 35.30° 75.33° Offshore Seabirds Cape Hatteras National Seashore NC 35.20° 75.53° Barrier Island Shorebirds, SeabCape Lookout National Seashore NC 34.60° 76.53° Barrier Island Shorebirds Onslow Bay NC 34.20° 77.78° Offshore/Coastal Seabirds, WaterfBald Head-Smith Island NC 33.87° 77.97° Coastal Shorebirds, WatCape Romain National Wildlife Refuge SC 33.02° 79,50° Barrier Island/Coastal Shorebirds, WatCrab Bank SC 32.98° 79.98° Coastal Seabirds Bird Key Stono SC 32.63° 79.98° Barrier Island Seabirds, ShorebLittle Tybee Island State Heritage Preserve GA 31.97° 80.90° Barrier Island Shorebirds, WatSt. Catherines Island GA 31.63° 81.15° Barrier Island Shorebirds, WatWassaw National Wildlife Refuge GA 31.55° 80.96° Coastal Shorebirds, WatAltamaha River Delta GA 31.30° 81.31° Coastal Shorebirds, WatJekyll Island GA 31.05° 81.42° Barrier Island Shorebirds, SeabCumberland Island National Seashore GA 30.83° 81.42° Barrier Island Seabirds, WaterfHuguenot Park-Nassau Sound FL 30.51° 81.45° Coastal Shorebirds, SeabDuval and Nassau Tidal Marshes FL 30.48° 81.44° Barrier Island/Coastal Shorebirds Fort George and Talbot Islands FL 30.45° 81.42° Coastal Shorebirds, SeabNorthern Atlantic Migrant Stopover FL 29.86° 81.27° Coastal Shorebirds, SeabMatanzas Inlet and River FL 29.71° 81.23° Coastal Shorebirds Cape Canaveral – Merritt Island FL 28.54° 80.67° Barrier Island/Coastal Shorebirds, WatAbbreviation: IBA = Important Bird Area. Source: National Audubon Society, Inc. (http://web4.audubon.org/bird/iba/index.html). 
Tables Tables-41

Table 4-18 

 

Plant, Invertebrate, and Fish Species and Species Groups Broadly Associated with Demersal and Pelagic Habitats 

in the Area of Interest Managed by the South Atlantic Fishery Management Council, 

Mid-Atlantic Fishery Management Council, New England Fishery Management Council, 

and/or Highly Migratory Species Office of the National Marine Fisheries Service 

Species or Species Groups SAFMC MAFMC NEFMC NMFS 

Demersal 

Coral, coral reefs, and live/hard bottom ■ -- -- -- 

Spiny lobster (Panulirus argus) ■ -- -- -- 

Snapper-grouper complex (73 species) ■ -- -- -- 

Tilefish (Lopholatilus chamaeleonticeps) ■ ■ -- -- 

Black sea bass (Centropristis striata) ■ ■ -- -- 

Scup (Stenotomus chrysops) ■ ■ -- -- 

Surfclam (Spisula solidissima) -- ■ -- -- 

Ocean quahog (Arctica islandica) -- ■ -- -- 

Sea scallop (Placopecten magellanicus) -- -- ■ -- 

Calico scallop (Argopecten gibbus ) -- -- -- -- 

Golden crab (Chaceon fenneri) ■ -- -- -- 

Red crab (Chaceon quinquedens) -- -- ■ -- 

Shrimps (Penaeidae and Sicyonidae) ■ -- -- -- 

Red drum (Sciaenops ocellata) ■ -- -- -- 

Monkfish (Lophius americanus) -- ■ -- -- 

Spiny dogfish (Squalus acanthias) -- ■ ■ -- 

Offshore hake (Merluccius albidus) -- ■ ■ -- 

Silver hake (Merluccius bilinearis) -- -- ■ -- 

Red hake (Urophycis chuss) -- -- ■ -- 

Witch flounder (Glyptocephalus cynoglossus) -- -- ■ -- 

Summer flounder (Paralichthys dentatus) -- -- ■ -- 

Windowpane flounder (Scophthalmus aquosus) -- -- ■ -- 

Pelagic 

Sargassum ■ -- -- -- 

Long-finned squid (Loligo pealei) -- ■ -- -- 

Short-finned squid (Illix illecebrosus) -- ■ -- -- 

Cobia (Rachycentron canadum) ■ -- -- -- 

King mackerel (Scomberomorus cavalla) ■ -- -- -- 

Spanish mackerel (Scomberomorus maculatus) ■ -- -- -- 

Little tunny (Euthynnus alletteratus) ■ -- -- -- 

Bluefish (Pomatomus saltatrix) -- ■ -- -- 

Atlantic mackerel (Scomber scombrus) -- ■ -- -- 

Butterfish (Peprilus triacanthus) -- ■ -- -- 

Atlantic herring (Clupea harengus) -- -- ■ -- 

Small coastal sharks (5 species) -- -- -- ■

Large coastal sharks (17 species) -- -- -- ■

Pelagic sharks (6 species) -- -- -- -- 

Wahoo (Acanthocybium solandri) ■ -- -- -- 

Dolphin (Coryphaena hippurus) ■ -- -- -- 

Tunas and billfishes (Scombridae, Istiophoridae, Xiphiidae) -- -- -- ■

Abbreviations: MAFMC = Mid-Atlantic Fishery Management Council; NEFMC = New England Fishery 

Management Council; NMFC = Highly Migratory Species Office of the National Marine Fisheries Service; 

SAFMC = South Atlantic Fishery Management Council. 
Tables-42 Atlantic G&G Programmatic EIS 

Table 4-19 

 

Hard Bottom Species with Essential Fish Habitat Identified within the Area of Interest 

Species Eggs and Larvae Juveniles Adults 

Spiny lobster 

(Panulirus argus) 

Surface waters of the 

SAB and Gulf Stream Not in AOI 

Live/hard bottom and 

artificial reefs with mediumto high-profile outcroppings 

from nearshore to at least 

100-m water depths from 

Cape Hatteras, NC, to 

Cape Canaveral, FL 

Black sea bass 

(Centropristis striata) 

Surface waters of the 

AOI shelf from 

May-October 

Demersal soft and hard bottom 

habitats of the AOI shelf where 

water temperatures are greater than 

6 °C and salinity greater than 18 ppt

Demersal soft and hard 

bottom habitats of the AOI 

shelf where water 

temperatures are greater than 

6 °C and salinity greater than 

18 ppt 

Warsaw grouper 

(Epinephelus nigritus) 

Surface waters of the 

SAB and Gulf Stream 

including pelagic 

Sargassum

Live/hard bottom and artificial reefs 

with medium to high profile 

outcroppings from inner shelf to at 

least 200-m water depths 

Live/hard bottom and 

artificial reefs with medium 

to high profile outcroppings 

from 50- to at least 200-m 

water depths. Spawning 

occurs in the same area 

Snowy grouper 

(Epinephelus niveatus) 

Surface waters of the 

SAB and Gulf Stream 

including pelagic 

Sargassum

Live/hard bottom and artificial reefs 

with medium to high profile 

outcroppings from inner shelf to at 

least 200-m water depths 

Live/hard bottom and 

artificial reefs with medium 

to high profile outcroppings 

from 50- to at least 200-m 

water depths. Spawning 

occurs in the same area 

Gag grouper 

(Mycteroperca 

microlepis) 

Surface waters of the 

SAB and Gulf Stream 

including pelagic 

Sargassum

Not in AOI 

Live/hard bottom and 

artificial reefs with medium 

to high profile outcroppings 

from nearshore to at least 

100-m water depths from 

Cape Hatteras, NC, to Cape 

Canaveral, FL. Spawning 

occurs in winter months in 

30-100 m depths 

Scamp 

(Mycteroperca 

phenax) 

Surface waters of the 

SAB and Gulf Stream 

including pelagic 

Sargassum

Hard bottom areas on the shelf to the 

shelf edge from Cape Hatteras, NC, 

to Cape Canaveral, FL 

Hard bottom areas from 

Cape Hatteras, NC, to 

Cape Canaveral, FL 

Wreckfish 

(Polyprion 

americanus) 

Gulf Stream waters 

including pelagic 

Sargassum

Not enough information 

Live/hard bottom and 

artificial reefs with medium 

to high profile outcroppings 

in 800-1,200-m water depths 

Gray snapper 

(Lutjanus griseus) 

Surface waters of the 

SAB and Gulf Stream

Hard bottom and soft bottom areas 

on the shelf from Cape Hatteras, 

NC, to Cape Canaveral, FL 

Hard bottom areas from 

Cape Hatteras, NC, to 

Cape Canaveral, FL 
Tables Tables-43 

Table 4-19 Hard Bottom Species with Essential Fish Habitat Identified within the Area of Interest (AOI) 

(continued) 

Species Eggs and Larvae Juveniles Adults 

Red snapper 

(Lutjanus 

campechanus) 

Surface waters of the 

SAB and Gulf Stream Not in AOI 

Hard bottom areas from 

Cape Hatteras, NC, to 

Cape Canaveral, FL 

Lane snapper 

(Lutjanus synagris) 

Surface waters of the 

SAB and Gulf Stream Not in AOI 

Hard bottom areas from 

Cape Hatteras, NC, to 

Cape Canaveral, FL 

Vermilion snapper 

(Rhomboplites 

aurorubens) 

Surface waters of the 

SAB and Gulf Stream

Hard bottom areas on the shelf to the 

shelf edge from Cape Hatteras, NC, 

to Cape Canaveral, FL 

Hard bottom areas from 

Cape Hatteras, NC, to 

Cape Canaveral, FL 

Scup 

(Stenotomus chrysops) Not in AOI Not in AOI 

Demersal waters of the 

continental shelf off the 

middle Atlantic south to 

Cape Hatteras, NC 

Blueline tilefish 

(Caulolatilus microps) 

Gulf Stream waters 

including pelagic 

Sargassum

Not enough information 

Soft or rough bottom in water 

depths between 100 and 

400 m 

Tilefish 

(Lopholatilus 

chamaleonticeps) 

Water column on the 

outer continental shelf 

and slope throughout 

the AOI boundary in 

temperatures between 

7.5 and 17.5 °C 

Semi-lithified clay substrate on the 

outer continental shelf and slope 

throughout the AOI in bottom water 

temperatures which range from 

9-14 °C, in depths between 100 and 

300 m 

Semi-lithified clay substrate 

on the outer continental shelf 

and slope throughout the AOI 

in bottom water temperatures 

ranging from 9-14 °C, in 

depths between 100 and 

300 m 

AOI = Area of Interest. 

Sources: SAFMC, 1998; MAFMC, 1998a, 2008a. 
Tables-44 Atlantic G&G Programmatic EIS 

Table 4-20 

 

Soft Bottom Species and Life Stages with Essential Fish Habitat Identified within the Area of Interest 

Species Eggs and Larvae Juveniles Adults 

Surfclam 

(Spisula solidissima) Not enough information 

In substrate, to a depth of 3 ft 

below the water/sediment surface 

throughout the MAB from the 

shoreline out to 70 m 

In substrate, to a depth of 3 ft 

below the water/sediment 

surface throughout the MAB 

from the shoreline out to 

70 m 

Ocean quahog 

(Arctica islandica) Not enough information 

In substrate, to a depth of 3 ft 

below the water/sediment surface 

throughout the MAB in water 

depths from 10-244 m 

In substrate, to a depth of 3 ft 

below the water/sediment 

surface throughout the MAB 

from the shoreline out to 

10-244 m 

Sea scallop 

(Placopecten 

magellanicus) 

Bottom habitats in the 

middle Atlantic south to 

the VA-NC border; Eggs 

are heavier than seawater 

and remain on the seafloor 

until they develop into the 

first free-swimming larval 

stage. Generally, eggs are 

thought to occur where 

water temperatures are 

below 17 °C. Larvae 

occur in pelagic waters 

and bottom habitats with a 

substrate of gravelly sand, 

shell fragments, and 

pebbles, or on various red 

algae, hydroids, amphipod 

tubes, and bryozoans in 

the MAB south to the 

VA-NC border where sea 

surface temperatures are 

below 18 °C and salinities 

are between 16.9 and 

30 ppt 

Bottom habitats with a substrate 

of cobble, shells, and silt in the 

middle Atlantic south to the 

VA-NC border where water 

temperatures are below 15 °C and 

water depths range from 

18-110 m 

Bottom habitats with a 

substrate of cobble, shells, 

coarse/gravelly sand, and 

sand in the middle Atlantic 

south to the VA-NC border 

where water temperatures are 

below 21 °C, water depths 

range from 18 to 110 m, and 

salinities are above 16.5 ppt. 

Spawning occurs from May 

through October, with peaks 

in May and June 

Calico scallop 

(Argopecten gibbus) Not enough information 

Unconsolidated sediments 

including hard sand bottoms, sand 

and shell hash, quartz sand, 

smooth sand-shell-gravel, and 

sand and dead shell in 13-94 m, 

with concentrations occurring off 

Cape Canaveral, FL (Stuart to 

St. Augustine) and sporadically 

off Cape Lookout, NC, in 

19-31 m, and offshore of the 

SC/GA border in 37-45 m 

Unconsolidated sediments 

including hard sand bottoms, 

sand and shell hash, quartz 

sand, smooth 

sand-shell-gravel, and sand 

and dead shell in 13-94 m, 

with concentrations occurring 

off Cape Canaveral, FL 

(Stuart to St. Augustine), and 

sporadically off Cape 

Lookout, NC, in 19-31 m, 

and offshore of the SC/GA 

border in 37-45 m 
Tables Tables-45 

Table 4-20 Soft Bottom Species and Life Stages with Essential Fish Habitat Identified within the Area of Interest 

(continued) 

Species Eggs and Larvae Juveniles Adults 

Golden crab 

(Chaceon fenneri) 

Eggs are brooded attached 

to the underside of the 

female crab until they 

hatch into larvae and are 

released into the water 

column. Egg-bearing 

females are most 

commonly found on the 

shallow continental slope 

between 300 and 600 m; 

larvae occur in pelagic 

waters of the Gulf Stream 

Soft bottom including 

foraminiferal ooze, dead coral 

mounds, dunes, and black pebble 

habitat in water depths of 

367-549 m 

Soft bottom including 

foraminiferal ooze, dead coral 

mounds, dunes, and black 

pebble habitat in water depths 

of 367-549 m 

Red crab 

(Chaceon quinquedens) 

Eggs are brooded attached 

to the underside of the 

female crab until they 

hatch into larvae and are 

released into the water 

column. Egg-bearing 

females are most 

commonly found on the 

shallow continental slope 

between 200 and 400 m 

where temperatures are 

typically between 4 and 

10 °C and water depths 

range from 200-400 m to 

Cape Hatteras, NC. 

Larvae occur in the water 

column from the surface to 

the seafloor across the 

200 to 1,800 m along the 

MAB south to 

Cape Hatteras, NC where 

water temperatures range 

between 4 and 25 °C, 

salinities between 29 and 

36 ppt, and dissolved 

oxygen between 5 and 

8 ml/L; larvae appear to be 

most common during 

January through June 

Bottom habitats of the continental 

slope with a substrate of silts, 

clays, and all silt-clay-sand 

composites within the depths of 

700-1,800 m along the southern 

flank of Georges Bank and south 

to Cape Hatteras, NC, where 

water temperatures are between 

4 and 10 °C, and salinities are 

approximately 35 ppt, and 

dissolved oxygen range between 

3 and 7 mg/L 

Bottom habitats of the 

continental slope with a 

substrate of silts, clays, and 

all silt-clay-sand composites 

within the depths of 200 to 

1,300 m along the southern 

flank of Georges Bank and 

south to Cape Hatteras, NC 

where water temperatures are 

between 5 and 14 °C, 

salinities average 35 ppt, and 

dissolved oxygen range 

between 3 and 8 mg/L 

Royal red shrimp 

(Pleoticus robustus) 

Pelagic Gulf Stream 

waters 

Soft bottom including blue/black 

mud, sand, muddy sand, and 

white calcareous mud on the 

upper continental slope in water 

depths of 180-475 m 

Soft bottom including 

blue/black mud, sand, muddy 

sand, and white calcareous 

mud on the upper continental 

slope in water depths of 

180-475 m 
Tables-46 Atlantic G&G Programmatic EIS 

Table 4-20 Soft Bottom Species and Life Stages with Essential Fish Habitat Identified within the Area of Interest 

(continued) 

Species Eggs and Larvae Juveniles Adults 

Rock shrimp 

(Syconia spp.) 

Eggs and larvae in high 

salinity coastal waters of 

the SAB 

Terrigenous and biogenic sand 

bottom habitats from 18-182 m in 

depth with highest concentrations 

occurring between 34 and 55 m in 

all areas from NC to Cape 

Canaveral, FL 

Terrigenous and biogenic 

sand bottom habitats from 

18-182 m in depth with 

highest concentrations 

occurring between 34 and 

55 m. areas from NC to Cape 

Canaveral, FL. Spawning 

occurs in the same area 

Brown shrimp 

(Farfantepenaeus 

aztecus) 

Eggs and larvae in high 

salinity coastal waters of 

the SAB 

Not in AOI (primarily in inshore 

waters) 

Nearshore SAB shelf with 

medium to fine grained 

sediment. Spawning occurs 

offshore 

Pink shrimp 

(Farfantepenaeus 

duorarum) 

Eggs and larvae in high 

salinity coastal waters of 

the SAB 

Not in AOI (primarily in inshore 

waters) 

Coarse and particularly 

calcareous bottom sediments 

in SAB from mid- to outer 

shelf depths. Spawning 

occurs offshore 

White shrimp 

(Litopenaeus setiferus) 

Eggs and larvae in high 

salinity coastal waters of 

the SAB 

Not in AOI (primarily in inshore 

waters) 

Nearshore SAB shelf with 

medium to fine grained 

sediment 

Red drum 

(Sciaenops ocellata) 

Eggs in high salinity 

coastal waters; larvae not 

in AOI (primarily in 

inshore waters) 

Not in AOI (primarily in inshore 

waters) 

High salinity coastal waters 

of the AOI from VA to Cape 

Canaveral, FL 

Monkfish 

(Lophius americanus) 

MAB shelf areas south to 

Cape Hatteras, NC, with 

water temperatures below 

15 °C and depths from 

15-1,000 m for eggs and 

25-1,000 m for larvae; egg 

veils and larvae are most 

often observed from 

March to September 

MAB shelf areas with water 

temperatures below 13 °C, depths 

from 25 to 200 m, and a salinity 

range from 29.9 to 36.7 ppt 

Bottom habitats with 

substrates of a sand-shell mix, 

algae covered rocks, hard 

sand, pebbly gravel, or mud 

along the outer MAB shelf 

Offshore hake 

(Merluccius albidus) 

MAB shelf to Cape 

Hatteras, NC where water 

temperatures less than 

20 °C and water depths 

less than 1,250 m all year 

at depths from 110-270 m 

(eggs) and 70-130 m 

(larvae) 

Bottom habitats along the outer 

MAB shelf south to Cape 

Hatteras, NC, generally where 

water temperatures are below 

12 °C and depths range from 

170-350 m 

Bottom habitats along the 

outer MAB shelf south to 

Cape Hatteras, NC, where 

water temperatures are below 

12 °C and depths range from 

150-380 m. Spawning occurs 

throughout the year at depths 

from 330-550 m 

Silver hake 

(Merluccius bilinearis) 

Surface waters of the 

MAB south to Cape 

Hatteras where sea surface 

temperatures are below 

20 °C and water depths are 

50-130 m; larvae are 

observed all year, with 

peaks from July through 

September 

Bottom habitats of all substrate 

types on the MAB shelf south to 

Cape Hatteras, NC, where water 

temperatures are below 21 °C, 

water depths 20-270 m, and 

salinities are greater than 20 ppt 

Bottom habitats of all 

substrate types on the MAB 

shelf south to Cape Hatteras, 

NC, where water 

temperatures are below 22 °C 

and depths between 30 and 

325 m. Spawning occurs in 

the same area where water 

temperatures are below 13 °C
Tables Tables-47 

Table 4-20 Soft Bottom Species and Life Stages with Essential Fish Habitat Identified within the Area of Interest 

(continued) 

Red hake 

(Urophycis chuss) 

Continental shelf off the 

MAB south to Cape 

Hatteras, NC, where sea 

surface temperatures are 

below 10 °C along the 

inner shelf (eggs) or 19 °C 

in water depths less than 

200 m (larvae), in a 

salinity greater than 

0.5 ppt; May through 

November (eggs) to 

December (larvae), with 

peaks in June and July 

(eggs) and 

September-October 

(larvae) 

Bottom habitats with a substrate 

of shell fragments, including 

areas with an abundance of live 

scallops on the shelf off the 

middle Atlantic south to Cape 

Hatteras, NC, where water 

temperatures are below 16 °C, 

depths are less than 100 m, and 

salinity ranges from 31-33 ppt 

Bottom habitats in 

depressions with a substrate 

of sand and mud on the 

continental shelf off the 

middle Atlantic south to Cape 

Hatteras, NC, where water 

temperatures are below 

12 °C, water depths range 

from 10-130 m, and salinity 

ranges from 33-34 ppt. 

Spawning occurs in water 

depths less than 100 m and 

salinity less than 25 ppt from 

May-November, with peaks 

in June and July 

Witch flounder 

(Glyptocephalus 

cynoglossus) 

Surface waters to 250 m 

on the MAB shelf off the 

middle Atlantic south to 

Cape Hatteras, NC, where 

sea surface temperatures 

are below 13 °C over deep 

water with high salinities; 

larvae are most often 

observed from March 

through November, with 

peaks in May-July 

Bottom habitats with a 

fine-grained substrate along the 

outer MAB shelf south to Cape 

Hatteras, NC, where witch water 

temperatures are below 13 °C, 

depths range from 50-450 m, and 

salinity ranges from 34-36 ppt 

Bottom habitats with a 

fine-grained substrate along 

the outer MAB continental 

shelf south to Chesapeake 

Bay, where water 

temperatures are below 

13 °C, depths range from 

25-300 m, and salinity ranges 

from 32-36 ppt. Spawning 

occurs from March through 

November, with peaks in 

May-August 

Summer flounder 

(Paralichthys dentatus) 

Surface waters of the 

MAB shelf south to Cape 

Canaveral, FL; in water 

depths from shore to 98 m 

(eggs) and from 10-70 m 

(larvae) 

Demersal waters of the MAB 

shelf south to Cape Canaveral, 

FL, to water depths of 152 m 

Demersal waters of the MAB 

shelf south to Cape 

Canaveral, FL, to water 

depths of 152 m. Spawning 

occurs between October and 

May 

Windowpane 

(Scophthalmus aquosus) 

Pelagic waters of the MAB 

south to Cape Hatteras, 

NC where sea surface 

temperatures are less than 

20 °C and water depths 

less than 70 m; eggs and 

larvae are often observed 

from February-November 

with peaks in May and 

October 

Bottom habitats with a substrate 

of mud or fine-grained sand on 

the MAB shelf south to Cape 

Hatteras, NC, where water 

temperatures are below 25 °C, 

depths range from 1-100 m, and 

salinities range between 5.5 and 

36 ppt 

Bottom habitats with a 

substrate of mud or 

fine-grained sand on the 

MAB shelf south to the 

VA-NC border where water 

temperatures are below 

26.8 °C, depths range from 

1-75 m, and salinities range 

between 5.5 and 36 ppt. 

Spawning occurs from 

February-December with a 

peak in May 

Abbreviations: AOI = Area of Interest; MAB = Mid-Atlantic Bight; SAB = South Atlantic Bight. 

Sources: MAFMC, 1998b, 2008a; SAFMC, 1998; NEFMC, 1998a,b,c; 2002. 
Tables-48 Atlantic G&G Programmatic EIS 

Table 4-21 

 

Coastal Pelagic Species and Life Stages with Essential Fish Habitat Identified within the Area of Interest 

Species Eggs and Larvae Juveniles Adults 

Longfin squid 

(Loligo pealei) 

Coastal and offshore 

bottom habitats from 

Georges Bank southward 

to Cape Hatteras, NC egg 

masses are found attached 

to rocks and boulders on 

sand or mud bottom, as 

well as attached to aquatic 

vegetation where bottom 

water temperatures range 

between 10and 23 °C, 

salinities range from 

30-32 ppt, and depths are 

less than 50 m 

Pelagic waters of the continental 

shelf from the Gulf of Maine 

through Cape Hatteras, NC, from 

shore to 213 m water depths in 

temperatures ranging from 

3.8-27 °C 

Pelagic waters of the continental 

shelf from the Gulf of Maine 

through Cape Hatteras, NC, from 

shore to 305 m water depths in 

temperatures ranging from 

3.8-27 °C 

Shortfin squid 

(Illex illecebrosus) 

Pelagic waters of the continental 

shelf from the Gulf of Maine 

through Cape Hatteras, NC, from 

shore to 183 m water depths in 

temperatures ranging from 

2.2-22.8 °C 

Pelagic waters of the continental 

shelf from the Gulf of Maine 

through Cape Hatteras, NC, from 

shore to 183 m water depths in 

temperatures ranging from 

3.8-19 °C 

Atlantic herring 

(Clupea harengus) Not in AOI 

Pelagic waters and bottom 

habitats in the MAB south to 

Cape Hatteras, NC. Generally, 

the following conditions exist 

where Atlantic herring juveniles 

are found: water temperatures 

below 10 °C, water depths from 

15-135 m, and a salinity range 

from 26-32 ppt 

Pelagic waters and bottom 

habitats in the MAB south to 

Cape Hatteras, NC. Generally, 

the following conditions exist 

where Atlantic herring adults are 

found: water temperatures below 

10 °C, water depths from 

20-130 m, and salinity above 

from 28 ppt 

Cobia

(Rachycentron 

canadum) 

Pelagic waters of SAB and 

MAB from shore to the 

shelf edge 

Shelf waters of SAB and MAB; 

artificial and natural hard 

bottom; associates with larger 

nekton (i.e., sharks, rays, sea 

turtles) 

Shelf waters of SAB and MAB; 

artificial and natural hard bottom 

structures; associates with larger 

nekton (i.e., sharks, rays, sea 

turtles) 

King mackerel

(Scomberomorus 

cavalla) 

Pelagic waters of SAB and 

MAB from shore to the 

shelf edge 

Shelf waters of SAB and MAB; 

associates with artificial and 

natural hard bottom 

Shelf waters of SAB and MAB; 

associates with artificial and 

natural hard bottom 

Spanish mackerel 

(Scomberomorus 

maculatus) 

Pelagic waters of SAB and 

MAB from shore to the 

shelf edge 

Shelf and inshore waters of SAB 

and MAB; associates with 

artificial and natural hard bottom

Shelf and inshore waters of SAB 

and MAB; associates with 

artificial and natural hard bottom

Little tunny 

(Euthynnus 

alletteratus) 

Pelagic waters of SAB and 

MAB from shore to 

beyond the shelf edge 

Shelf waters of MAB and SAB; 

associates with artificial and 

natural hard bottom 

Shelf waters of MAB and SAB; 

associates with artificial and 

natural hard bottom 

Atlantic mackerel

(Scomber scomber) 

Shelf waters of MAB from 

Maine to Cape Hatteras, 

NC 

Shelf waters of MAB from 

Maine to Cape Hatteras, NC to 

320 m 

Shelf waters from Maine to Cape 

Hatteras, NC (from shore to 

320 m 

Bluefish

(Pomatomus saltatrix) 

Shelf waters of MAB from 

Maine to Cape Hatteras, 

NC 

Estuaries and coastal waters of 

the AOI 

Shelf and inshore waters of SAB 

and MAB 
Tables Tables-49 

Table 4-21 Coastal Pelagic Species and Life Stages with Essential Fish Habitat Identified within the Area of 

Interest (AOI) (continued) 

Species Eggs and Larvae Juveniles Adults 

Butterfish 

(Peprilus triacanthus) 

Pelagic waters of MAB 

from shore to beyond the 

shelf edge where 

temperatures range from 

11-17 °C 

Pelagic waters of MAB from 

shore to beyond the shelf edge 

where temperatures are 11-20 °C 

and water depths range from 

10-366 m 

Pelagic waters of MAB from 

shore to beyond the shelf edge 

where temperatures are 3-28 °C 

and water depths range from 

10-366 m 

Spiny dogfish 

(Squalus acanthias) Does not apply 

Shelf waters of the entire AOI to 

water depths of 390 m (1,280 ft) 

where temperatures range from 

3-28 oC 

Shelf waters of the entire AOI to 

water depths of 450 m (1,476 ft) 

where temperatures range from 

3-28 oC 

Abbreviations: AOI = Area of Interest; MAB = Mid-Atlantic Bight; SAB = South Atlantic Bight. 

Adapted from SAFMC, 1998; MAFMC, 1998c, 2008b.
Tables-50 Atlantic G&G Programmatic EIS 

Table 4-22 

 

Small Coastal Shark Species and Life Stages with Essential Fish Habitat Identified within the Area of Interest 

Species Neonate/Early Juveniles Late Juveniles/Subadults Adults 

Angel shark 

(Squatina dumerili) 

Off the coast of southern NJ, 

DE, and MD from 39°-38° N in 

shallow coastal waters out to 

the 25-m isobath, including the 

mouth of Delaware Bay 

Off the coast of southern NJ, 

DE, and MD from 39°-38° N in 

shallow coastal waters out to 

the 25-m isobath, including the 

mouth of Delaware Bay 

Off the coast of southern NJ, 

DE, and MD from 39°-

38° N in shallow coastal 

waters out to the 25-m 

isobath, including the mouth 

of Delaware Bay 

Bonnethead shark 

(Sphyrna tiburo) 

Shallow coastal waters, inlets, 

and estuaries less than 25 m 

deep from Jekyll Island, GA, to 

just north of Cape Canaveral, 

FL 

Shallow coastal waters, inlets, 

and estuaries less than 25 m 

deep from Cape Fear, NC, to 

West Palm Beach, FL 

Shallow coastal waters, 

inlets and estuaries from 

Cape Fear, NC, to Cape 

Canaveral, FL 

Atlantic sharpnose shark 

(Rhizoprionodon 

terraenovae) 

Shallow coastal areas including 

bays and estuaries out to the 

25-m isobath from Daytona 

Beach, FL north to Cape 

Hatteras, NC 

From Daytona Beach, FL, 

north to Cumberland Island, 

GA; Hilton Head Island, SC, 

north to Cape Hatteras, NC, out 

to the 25-m isobath (slightly 

deeper – to the 50 m isobath – 

off NC) 

From Cape May, NJ, south 

to the NC/SC border; 

shallow coastal areas north 

of Cape Hatteras, NC, to the 

25-m isobath; south of Cape 

Hatteras between the 25- 

and 100-m isobaths; 

offshore St. Augustine, FL, 

to Cape Canaveral, FL, from 

inshore to the 100-m isobath

Blacknose shark 

(Carcharhinus 

acronotus) 

Shallow coastal waters less 

than 25 m deep from the 

GA/FL border to 

Cape Canaveral, FL 

Shallow coastal waters less 

than 25 m deep from the 

GA/FL border to Cape 

Canaveral, FL 

Shallow coastal waters to 

the 25-m isobath from 

St. Augustine, FL south to 

Cape Canaveral, FL 

Finetooth shark 

(Carcharhinus isodon) 

Shallow coastal waters of SC, 

GA, and FL out to the 25-m 

isobath from 33°-30° N 

Shallow coastal waters of SC, 

GA, and FL out to the 25-m 

isobath from 33°-30° N 

Shallow coastal waters of 

SC, GA, and FL out to the 

25-m isobath from 33°-30° 

N 

Source: USDOC, NMFS, 2009a. 
Tables Tables-51 

Table 4-23 

 

Large Coastal Shark Species and Life Stages with Essential Fish Habitat Identified within the Area of Interest 

Species Neonate/Early Juveniles Late Juveniles/Subadults Adults 

Basking shark 

(Cetorhinus maximus) Insufficient information 

Offshore the mid-Atlantic U.S. 

south of Nantucket Shoals at 

70W to the northern edge of 

Cape Hatteras, NC, at 35.5° N 

in waters from 50-200 m deep 

Not in AOI 

Scalloped hammerhead 

(Sphyrna lewini) Not in AOI 

Pelagic waters of the U.S. 

Atlantic seaboard from the 

shoreline out to the 200-m 

isobath from 39° N south to the 

Florida Keys 

Pelagic waters of the South 

from 36.5°-33° N between 

the 25 and 200-m isobaths 

Great hammerhead 

(Sphyrna mokarran) Insufficient information 

Off the FL coast, all shallow 

coastal waters out to the 100-m 

isobath from 30° N south 

around peninsular FL to 82.5° 

W, including Florida Bay and 

adjacent waters east of 81.5° W 

(north of 25°N), and east of 

82.5° W 

Off the entire east coast of 

FL, all shallow coastal 

waters out to the 100-m 

isobath, south of 30° N, 

including the west coast of 

FL to 85.5° W 

Bigeye thresher shark 

(Alopias superciliosus) Insufficient information 

Offshore NC from 36.5°-34°N, 

between the 200- and 2,000-m 

isobaths 

Offshore NC from 

35.5°-35°N, between the 

200- and 2,000-m isobaths 

White shark 

(Carcharodon 

carcharias) 

Insufficient information 

Offshore northern NJ and Long 

Island, NY, in pelagic waters 

from the 25- to 100-m isobaths 

in the New York Bight area, 

bounded to the east at 71.5° W 

and to the south at 39.5° N; 

also, offshore Cape Canaveral, 

FL, between the 25- and 100-m 

isobaths from 29.5° N south to 

28° N 

Insufficient information 

Nurse shark 

(Ginglymostoma 

cirtatum) 

Not in AOI 

Shallow coastal waters from 

the shoreline to the 25-m 

isobath off the east coast of FL 

from south of Cumberland 

Island, GA (at 30.5° N) 

Shallow coastal waters from 

the shoreline to the 25-m 

isobath off the east coast of 

FL from south of 

Cumberland Island, GA 

(at 30.5° N) 

Bignose shark 

(Carcharhinus altimus) 

From offshore Delmarva 

Peninsula (38° N) to Bull’s 

Bay, SC (32° N), between the 

100- and 200-m isobaths 

From offshore Delmarva 

Peninsula (38° N) to Bull’s 

Bay, SC (32° N), between the 

100- and 500-m isobaths 

Insufficient information 

Blacktip shark 

(Carcharhinus 

limbatus) 

Shallow coastal waters to the 

25-m isobath from Bull’s Bay, 

SC, at 33.5° N, south to Cape 

Canaveral, FL, at 28.5° N 

Shallow coastal waters from 

the shoreline to the 25-m 

isobath from Cape Hatteras, 

NC, at 35.25° N to 29° N at 

Ponce de Leon Inlet, 

St. Augustine, FL 

Shallow coastal waters of 

the Outer Banks, NC, from 

the shoreline to the 200-m 

isobath between 36° N and 

34.5° N; shallow coastal 

waters offshore to the 50-m 

isobath from St. Augustine, 

FL (30° N), to offshore Cape 

Canaveral, FL (28.5° N) 
Tables-52 Atlantic G&G Programmatic EIS 

Table 4-23 Large Coastal Shark Species and Life Stages with Essential Fish Habitat Identified within the Area of 

Interest (continued) 

Species Neonate/Early Juveniles Late Juveniles/Subadults Adults 

Bull shark 

(Carcharhinus leucas) 

In shallow coastal waters, 

inlets, and estuaries in waters 

less than 25 m deep from just 

north of Cape Canaveral, FL, at 

29° N to just south of Cape 

Canaveral, FL, at 28° N 

In shallow coastal waters, inlets 

and estuaries in waters less 

than 25 m deep from Savannah 

Beach, GA, at 32°N 

Not in AOI 

Dusky shark 

(Carcharhinus 

obscurus) 

Shallow coastal waters, inlets, 

and estuaries to the 25-m 

isobath from the eastern end of 

Long Island, NY, at 72° W 

south to Cape Lookout, NC, at 

34.5° N; from Cape Lookout 

south to West Palm Beach, FL 

(27.5° N), shallow coastal 

waters, inlets, and estuaries and 

offshore areas to the 90-m 

isobath 

Pelagic waters from VA/NC 

border to Jacksonville, FL, 

between the 25- and 200-m 

isobaths 

Pelagic waters from VA/NC 

border south to 

Ft. Lauderdale, FL, between 

the 25- and 200-m isobaths 

Night shark 

(Carcharhinus 

signatus) 

Insufficient information 

Pelagic waters from offshore 

Assateague Island, MD 

(38° N), south to offshore of 

Cape Fear, NC (33.5° N), from 

the 100- to 2,000-m isobaths 

Pelagic waters of the South 

Atlantic Bight from the 

100-m isobath to either the 

2,000-m isobath or 100 mi 

from shore 

Sandbar shark 

(Carcharhinus 

plumbeus) 

Shallow coastal waters, inlets, 

and estuaries in waters less 

than 25 m deep from Montauk, 

NY, to Cape Canaveral, FL 

(27.5° N) 

Shallow coastal waters, inlets, 

and estuaries in waters less 

than 25 m deep from Montauk, 

NY, to Cape Canaveral, FL 

(27.5° N) 

Areas on the east coast of 

the U.S., shallow coastal 

areas from the coast to the 

50-m isobath from 

Nantucket, MA, south to 

Miami, FL 

Silky shark 

(Carcharhinus 

falciformis) 

Waters off Cape Hatteras, NC, 

between the 100- and 2,000-m 

isobaths, plus shallow coastal 

waters just north and 

immediately west of Cape 

Hatteras; waters off 

St. Augustine, FL, south to off 

Miami in depths of 25-1,000 m 

(likely along the west edge of 

the Gulf Stream) 

From offshore Chesapeake 

Bay, MD, south to offshore of 

NC/SC border from the 50- to 

2,000-m isobaths 

Insufficient information 

Spinner shark 

(Carcharhinus 

brevipinna) 

Shallow coastal waters less 

than 25 m deep from Cape 

Hatteras, NC, to around FL 

Shallow coastal waters less 

than 200 m deep from GA/FL 

border south to Cape 

Canaveral, FL (28.5° N) 

Shallow coastal waters less 

than 100 m deep from 

GA/FL border south to 

Cape Canaveral, FL 

(28.5° N) 

Lemon shark 

(Negaprion 

brevirostris) 

Shallow coastal waters, inlets, 

and estuaries out to the 25-m 

isobath from Savannah, GA, at 

32° N, south to Indian River 

Inlet, FL at 29° N 

Shallow coastal waters, inlets, 

and estuaries offshore to the 

25-m isobath, west of 79.75° W 

from Bull’s Bay, SC, to south 

of Cape Canaveral (West Palm 

Beach), FL, at 28° N 

Shallow coastal waters, 

inlets, and estuaries offshore 

to the 25-m isobath from 

Cumberland Island, GA, at 

31° N to St. Augustine, FL, 

at 31° N 
Tables Tables-53 

Table 4-23 Large Coastal Shark Species and Life Stages with Essential Fish Habitat Identified within the Area of 

Interest (continued) 

Species Neonate/Early Juveniles Late Juveniles/Subadults Adults 

Tiger shark 

(Gaelocerdo cuvier) 

Shallow coastal waters to the 

200-m isobath from Canaveral, 

FL (27.5° N) to Montauk, NY 

Around the peninsula of FL to 

the 100-m isobath to the 

FL/GA border; north to Cape 

Lookout, NC, from the 

25- 100-m isobaths; from Cape 

Lookout north to just south of 

the Chesapeake Bay, MD, from 

inshore to the 100-m isobath 

Offshore from Chesapeake 

Bay, MD, south to 

Ft. Lauderdale, FL, to the 

western edge of the Gulf 

Stream 

Sand tiger shark 

(Carcharias taurus) 

Shallow coastal waters less 

than 25 m deep from Barnegat 

Inlet, NJ, to Cape Canaveral, 

FL (27.5° N) 

Insufficient information 

Shallow coastal waters less 

than 25 m deep from 

Barnegat Inlet, NJ, to 

Cape Canaveral, FL 

(27.5° N) 

Abbreviation: AOI = Area of Interest. 

Source: USDOC, NMFS, 2009a. 
Tables-54 Atlantic G&G Programmatic EIS 

Table 4-24 

 

Highly Migratory Fishes and Life Stages with Essential Fish Habitat Identified within the Area of Interest 

Species Eggs, and Larvae Juveniles/Subadults Adults 

Dolphin 

(Coryphaena hippurus) 

Pelagic waters of the Gulf 

Stream including the “Point” 

offshore NC 

Pelagic waters of the Gulf 

Stream including the “Point” 

offshore NC 

Pelagic waters of the Gulf 

Stream including the “Point” 

offshore NC 

Wahoo 

(Acanthocybium solandri) 

Pelagic waters of the Gulf 

Stream including the “Point” 

offshore NC 

Pelagic waters of the Gulf 

Stream including the “Point” 

offshore NC 

Pelagic waters of the Gulf 

Stream including the “Point” 

offshore NC 

Albacore 

(Thunnus alalunga) Insufficient information 

In pelagic waters with 

temperatures between 15.6 and 

19.4 C, offshore the U.S. east 

coast in the Mid-Atlantic Bight 

from the 50-m isobath to the 

2,000-m isobath from 71 W 

(northeast boundary) to 38 N 

(southwest boundary) 

In surface waters with 

temperatures between 

13.5 and 25.2 °C, offshore 

the U.S. eastern seaboard 

between the 100- and 

2,000-m isobaths from 

southeastern Georges Bank at 

41.25° N, south to 36.5° N, 

offshore the VA/NC border; 

also, in the Blake Plateau and 

Spur region, from 79° W east 

to the Exclusive Economic 

Zone (EEZ) boundary and 

29° N south to the EEZ 

boundary 

Bigeye tuna 

(Thunnus obesus) Insufficient information 

In surface waters from 

southeastern Georges Bank to 

the boundary of the EEZ to 

Cape Hatteras, NC, at 35° N 

from the 200-m isobath to the 

EEZ boundary; also, in the 

Blake Plateau region off Cape 

Canaveral, FL, from 29° N 

south to the EEZ boundary 

(28.25° N) and from 79° W east 

to the EEZ boundary 

(approximately 76.75° W) 

In pelagic waters from the 

surface to a depth of 250 m; 

from southeastern Georges 

Bank at the EEZ boundary to 

offshore Delaware Bay at 

38° N, from the 100-m 

isobath to the EEZ boundary; 

from offshore Delaware Bay 

south to Cape Lookout, NC 

(approximately the region off 

Cape Canaveral, FL), from 

29° N south to the EEZ 

boundary (28.25° N), and 

from 79° W east to the EEZ 

boundary (76.75° W) 

Bluefin tuna 

(Thunnus thynnus) 

In pelagic and near-coastal 

surface waters from the 

NC/SC border at 33.5° N, 

south to Cape Canaveral, FL, 

from 15 mi from shore to the 

200-m isobath; all waters 

from offshore Cape 

Canaveral at 28.25° N 

All inshore and pelagic surface 

waters warmer than 12 °C of the 

Gulf of Maine and Cape Cod 

Bay, MA, from Cape Ann, MA 

(~42.75° N), east to 69.75° W 

(including waters of the Great 

South Channel west of 

69.75° W), continuing south to 

and including Nantucket Shoals 

at 70.5° W to off Cape Hatteras, 

NC (approximately 35.5° N) 

South of 39° N, from the 

50-m isobath to the 2,000-m 

isobath to offshore Cape 

Lookout, NC, at 34.5°N. In 

pelagic waters from offshore 

Daytona Beach, FL (29.5°N) 

south to Key West (82° W) 

from the 100-m isobath to the 

EEZ boundary 
Tables Tables-55

Table 4-24 Highly Migratory Fishes and Life Stages with Essential Fish Habitat Identified within the Area of 

Interest (AOI) (continued) 

Species Eggs, and Larvae Juveniles/Subadults Adults 

Skipjack tuna 

(Katsuwonus pelamis) Not in AOI Not in AOI 

In pelagic surface waters 

from 20-31 °C in the 

Mid-Atlantic Bight, from the 

25-m isobath to the 200-m 

isobath from 71° W off the 

coast of Martha’s Vineyard, 

MA, south and west to 

35.5° N, offshore Oregon 

Inlet, NC 

Yellowfin tuna 

(Thunnus albacares) Not in AOI 

Pelagic waters from the surface 

to 100 m deep between 18C and 

31 °C from offshore Cape Cod, 

MA (70° W), southward to 

Jekyll Island, GA (31° N), 

between 200 and 2,000 m 

Pelagic waters from the 

surface to 100 m deep 

between 18 and 31 oC from 

offshore Cape Cod, MA 

(70°W), southward to Jekyll 

Island, GA (31°N), between 

200 and 2,000 m 

Swordfish 

(Xiphias gladius) 

From Cape Hatteras, NC 

(35° N) extending south 

around peninsular FL through 

the Gulf of Mexico to the 

U.S./Mexico border from the 

200-m isobath to the EEZ 

Pelagic waters warmer than 

18 °C from the surface to a 

depth of 500 m from 

Manasquan Inlet, NJ, at 40° N, 

east to 73° W, south to GA at 

31.5° N 

Pelagic waters warmer than 

13 °C from the surface to 

500 m deep from Cape Cod, 

MA, to Biscayne Bay, FL 

Blue marlin 

(Makaira nigricans) 

Offshore FL, identical to 

adult EFH in that area: from 

offshore Ponce de Leon Inlet 

(29.5 N) south to offshore 

Melbourne, FL, from the 

100-m isobath to 50 mi 

seaward (79.25 W); from 

offshore Melbourne, FL 

Pelagic waters warmer than 

24 °C from offshore Delaware 

Bay (38.5° N) south to Cape 

Lookout, NC, between the 200-

 and 2,000-m isobaths 

Pelagic waters warmer than 

24 °C from offshore 

Delaware Bay (38.5° N) 

south to Wilmington, NC 

(33.5° N), between 200 and 

2,000 m isobath 

White marlin 

(Tetrapterus albidus) Insufficient information 

Pelagic waters warmer than 

22 °C from offshore Georges 

Bank (41° N) south to Miami, 

FL (25.25° N), between the 

50- and 2,000-m isobaths 

Pelagic waters warmer than 

22 °C from offshore the 

northeast U.S. east coast 

from 33.75°to 39.25° N 

between the 50- and 2,000-m 

isobaths 

Sailfish 

(Istiophorus platypterus) Not in AOI Not in AOI 

Pelagic and coastal waters 

between 21 and 28 °C 

offshore of the U.S. southeast 

coast from 5 mi off the coast 

to 200 m water depths from 

36°-34° N, then from 5 mi 

offshore to 125 mi offshore 

or the EEZ boundary, 

whichever is closer to shore 

Longbill spearfish 

(Tetrapterus pfluegeri) Insufficient information 

Offshore NC from 36.5°-35° N 

from the 200-m isobath to the 

EEZ boundary 

Offshore of NC from 

37°-31° N, including the 

Charleston Bump 

Sources: SAFMC, 2003; USDOC, NMFS, 2009a. 
Tables-56 Atlantic G&G Programmatic EIS 

Table 4-25 

 

Pelagic Shark Species and Life Stages with Essential Fish Habitat Identified within the Area of Interest 

Species Neonate/Early Juveniles Late Juveniles/Subadults Adults 

Longfin mako 

(Isurus paucus) 

Pelagic waters of the 

northeast U.S. coast from the 

100-m isobath out to the 

Exclusive Economic Zone 

(EEZ) boundary from 

Georges Bank to Cape 

Hatteras (35° N) 

Pelagic waters of northeast 

U.S. coast from the 100-m 

isobath out to the EEZ 

boundary from Georges Bank 

to Cape Hatteras (35° N) 

Pelagic waters of northeast 

U.S. coast from the 100-m 

isobath out to the EEZ 

boundary from Georges 

Bank to Cape Hatteras 

(35° N) 

Shortfin mako 

(Isurus oxyrinchus)

Between the 50- and 

2,000-m isobaths from Cape 

Lookout, NC (35 N) north 

to just east of Georges Bank 

(42 N and 66 W) to the 

EEZ boundary; and between 

the 25- and 50-m isobaths 

from the VA/NC border to 

southwest of Georges Bank 

Between the 25- and 2,000-m 

isobaths from offshore Onslow 

Bay, NC, north to Cape Cod, 

MA, and extending west 

between 38 and 41.5 N to the 

EEZ boundary 

Between the 25- and 

2,000-m isobaths from 

offshore Cape Lookout, NC, 

north to Long Island, NY; 

and extending west between 

38.5 N and 41.5 N to the 

EEZ boundary 

Blue shark 

(Prionace galauca) Not in AOI 

Pelagic waters from offshore 

Cape Hatteras, NC (35° N), 

north to the EEZ boundary off 

Georges Bank, from the 25-m 

isobath to the EEZ 

Pelagic waters from offshore 

Cape Hatteras, NC (35° N), 

north to the EEZ offshore off 

Georges Bank from the 

25-m isobath to the EEZ 

Oceanic whitetip shark 

(Carcharhinus 

longimanus) 

In the vicinity of the 

Charleston Bump, from the 

200-m isobath to the 

2,000-m isobath, between 

32.5 and 31 N 

Offshore the southeast 

U.S. coast from 32-26 N, 

from the 200-m isobath to the 

EEZ boundary, or 75 W, 

whichever is nearer 

Pelagic waters offshore the 

U.S. east coast from the 

200-m isobath out to the 

EEZ boundary, from 

36-30 N 

Thresher shark 

(Alopias vulpinus) 

Offshore Long Island, NY, 

and southern New England 

in the northeastern U.S., in 

pelagic waters deeper than 

50 m, between 70 and 

73.5 W, south to 40 N 

Offshore Long Island, NY, and 

southern New England in the 

northeastern U.S., in pelagic 

waters deeper than 50 m, 

between 70 and 73.5 W, 

south to 40 N 

Offshore Long Island, NY, 

and southern New England 

in the northeastern U.S., in 

pelagic waters deeper than 

50 m, between 70 and 

73.5 W, south to 40 N 

Bigeye thresher shark 

(Alopias superciliosus) Insufficient information 

Offshore NC from 36.5-34 N, 

between the 200- and 2,000-m 

isobaths 

Offshore NC from 

35.5-35 N, between the 

200- and 2,000-m isobaths 

Source: USDOC, NMFS (2009a). 
Tables Tables-57 

Table 4-26 

 

Summary of Marine Fish Hearing Sensitivity 

Family Common Name 

of Taxa 

Highest 

Frequency 

Detected (Hz)1

Hearing 

Category2 Reference Notes 

Asceripensidae Sturgeon 800 2 Lovell et al., 2005; Meyer 

et al., 2010 

Several different species 

tested. Relatively poor 

sensitivity 

Anguillidae Eels 300 2 Jerkø et al., 1989 Poor sensitivity 

Batrachoididae Toadfishes 400 2 

Fish and Offutt, 1972; 

Vasconcelos and Ladich, 

2008 

-- 

Shad, menhden >120,000 4 Mann et al., 1997, 2001 Ultrasound detecting, but 

sensitivity relatively poor 

Clupeidae Anchovy, 

sardines, 

herrings 

4,000 4 Mann et al., 2001 Not detect ultrasound, and 

relativley poor sensitivitiy 

Chondrichthyes 

[Class] 

Rays, sharks, 

skates 1,000 1 Casper et al., 2003 Low frequency hearing, not 

very sensitive to sound 

Atlantic cod, 

haddock, 

pollack, hake 

500 2 

Chapman and Hawkins, 

1973; Sand and Karlsen, 

1986 

Probably detect infrasound 

(below 40 Hz). Best 

hearing 100-300 Hz. 

Gadidae 

Grenadiers -- 3? Deng et al., 2011 

Deep sea, highly 

specialized ear structures 

suggesting good hearing, 

but no measures of hearing 

Gobidae Gobies 400 1 or 2 Lu and Xu, 2009 -- 

Labridae Wrasses 1,300 2 Tavolga and Wodinksy, 

1963 -- 

Lutjanidae Snappers 1,000 2 Tavolga and Wodinksy, 

1963 -- 

Malacanthidae Tilefish 2 -- No data 

Moronidae Striped bass 1,000 2 Ramcharitar unpublished -- 

Pomacentridae Damselfish 1,500 – 2,000 2 Myrberg and Spires, 1980 -- 

Pomadasyidae Grunts 1,000 2 Tavolga and Wodinsky, 

1963 -- 

Polyprionidae Wreckfish -- 2 -- No data 

Drums, 

weakfish, 

croakers 

1,000 2 Ramcharitar et al., 2006 Hear poorly 

Sciaenidae 

Silver perch 3,000 3 Ramcharitar et al., 2004, 

2006 -- 

Serranidae Groupers -- 2 -- No data 

Yellowfin tuna 1,100 2 Iversen, 1967 With swim bladder 

Scombridae Tuna 1,000 1 Iversen, 1969 Without swim bladder 

Bluefin tuna 1,000 2 Song et al., 2006 Based only on ear anatomy 

Notes: See text for important caveats. 

 For taxa shaded gray, hearing capabilities can only be surmised from morphological data. 1

 Lower frequency of hearing is not given since, in most studies, the lower end of the hearing bandwidth is more a function of the 

equipment used than determination of actual lowest hearing threshold. In all cases, fish hear below 100 Hz, and there are some

species studied, such as Atlantic cod, Atlantic salmon, and plaice, where fish have been shown to detect infrasound, or sounds 

below 40 Hz. 2

 See Chapter 4.2.5.1.4 for an explanation. 

Source: Appendix J (data compiled from Fay [1988] and Nedwell et al. [2004]). Scientific names marked with an asterisk have 

a different name in the literature (updated names are from www.fishbase.org). 
Tables-58 Atlantic G&G Programmatic EIS 

Table 4-27 

 

Commercial Landings within the Area of Interest during 2006-2009 

Commercial Landings (metric tons) State 

2006 2007 2008 2009 

Virginia 193,339.00 220,110.70 189,383.10 193,346.80 

North Carolina 31,182.10 28,541.60 32,300.40 31,281.10 

Maryland 23,235.90 28,038.30 28,889.80 30,986.60 

Florida (East Coast) 12,256.60 11,428.90 11,932.50 12,474.30 

South Carolina 4,804.10 4,223.10 4,572.40 4,252.70 

Georgia 3,762.00 3,586.90 4,057.20 3,369.50 

Delaware 1,981.60 2,213.80 1,982.50 2,272.60 

Total 270,561.30 298,143.30 273,117.90 277,983.60 

Source: USDOC, NMFS, 2011k. 

Table 4-28 

 

Primary Commercial Species Landed with the Most Economic Value for Each State 

within the Area of Interest during 2006-2009 

State Commercial Species 

Delaware Blue crab, Eastern oyster, and striped bass. Other important commercial species 

included snails (conch), knobbed whelk, American eel, and black sea bass. 

Maryland Blue crab, striped bass, and clams. Other important commercial species were sea 

scallops, oysters, and softshell blue crab. 

Virginia Sea scallops, menhaden, and blue crab. Other important commercial species were 

quahog clam, Atlantic croaker, and striped bass. 

North Carolina Blue crab, white shrimp, and summer flounder. Other important commercial species 

were brown shrimp, Atlantic croaker, and quahog clam. 

South Carolina White shrimp, blue crab, and Eastern oyster. Other important commercial species 

were gag grouper, scamp, and vermilion snapper. 

Georgia 

White shrimp, blue crab, shrimp (Dendrobranchiata), and finfish (unclassified). Other 

economically important species were quahog clam, brown shrimp, and shellfish 

(unclassified). 

Florida (East Coast) White shrimp, king mackerel, blue crab, and rock shrimp. Other important 

commercial species were spiny lobster, swordfish, and Spanish mackerel. 

Source: USDOC, NMFS, 2011k. 
Tables Tables-59 

Table 4-29 

 

Commercial Fishing Landings and Value for Each State within the Area of Interest during 2009 

Distance from Shore 

Landings 0-4.8 km Landings 4.8-322 km Landings >322 km State 

Thousands 

of kg 

Thousands 

of Dollars 

Thousands 

of kg 

Thousands 

of Dollars 

Thousands 

of kg 

Thousands 

of Dollars 

Delaware 1,864 6,106 118 445 -- -- 

Maryland 20,614 55,633 4,735 11,719 -- -- 

Virginia 35,390 63,015 153,962 91,360 -- -- 

North Carolina 23,066 53,908 8,143 25,560 -- -- 

South Carolina 2,191 6,599 2,090 10,317 -- -- 

Georgia 2,209 6,556 1,131 5,110 -- -- 

Florida (East Coast) 4,364 13,831 8,020 26,784 -- -- 

Source: USDOC, NMFS, 2011k (The NMFS indicates that these are preliminary annual landings and are subject to 

change; the numbers differ somewhat from the annual State totals reported in Table 4-23). 
Tables-60 Atlantic G&G Programmatic EIS 

Table 4-30 

 

Seasonal and/or Area Closures to Commercial Fishing in Federal Waters Offshore 

the Mid-Atlantic and South Atlantic States 

Closed or Restricted Area Location Season Gear Restrictions or 

Protection Measures Reason/Purpose 

Deepwater MPAs: 

Snowy Grouper Wreck; 

Northern South Carolina; 

Edisto; Charleston Deep 

Artificial Reef; Georgia; 

and North Florida 

Cape Fear, NC to 

Jacksonville, FL (two 

others offshore south FL 

are outside the Area of 

Interest) 

Year-round No bottom longline 

gear 

Protect 

snapper-grouper 

complex species 

Proposed deepwater 

Lophelia coral HAPCs: 

Cape Lookout, Cape 

Fear, Blake Ridge Diapir, 

and Stetson-Miami 

Terrace 

South Atlantic Bight Year-round 

No anchors or 

chains; bottom 

longline, trawl (midwater and bottom), 

dredge, pot, or trap 

gear prohibited 

Protect deepwater 

corals 

Oculina Bank HAPC and 

Experimental Closed 

Area 

Offshore FL Year-round 

In HAPC, no bottom 

longline, bottom 

trawl, dredge, or 

trap/pot gear; in 

experimental closed 

area, no fishing for 

snapper-grouper 

species 

Protect deepwater 

corals; protect 

snapper-grouper 

complex species 

SMZs (51 sites) Offshore SC, GA, and 

FL Year-round 

Restrictions vary; 

examples include 

prohibitions on 

powerhead, bottom 

longline, fish traps 

or pots, and 

hydraulic or electric 

reels 

Protect 

snapper-grouper 

complex species 

Allowable octocoral 

closed area 

Atlantic EEZ north of 

28°35.1’ N Year-round 

No harvest or 

possession of 

octocoral 

Protect deepwater 

corals 

Pelagic Sargassum area 

All EEZ waters south of 

34° N and waters within 

100 nmi of the coast 

from 34° N to the 

NC/SC border 

July 1-October 31 

All Sargassum

harvest prohibited in 

the closed area; 

elsewhere prohibited 

July-October, with 

catch limits and 

restrictions on mesh 

and frame size of 

nets 

Protect Sargassum as 

habitat for sea turtles 

and essential fish 

habitat for snappers, 

groupers, and coastal 

migratory pelagic 

fishes 

Longline closed areas 

All waters south of 

27°10’ N, and waters 

north of 27°10’ N where 

depth is <91 m (300 ft) 

Year-round No longline gear for 

snapper-grouper 

Protect 

snapper-grouper 

complex species 

Charleston Bump Area Offshore NC and SC 

and Jekyll Island, GA February 1-April 30 No pelagic or bottom longline gear 

Protect juvenile 

swordfish and reduce 

bycatch 

East Florida Coast Area 

Offshore Jekyll Island, 

GA; FL east coast; Key 

West, FL 

Year-round No pelagic or bottom 

longline gear 

Protect juvenile 

swordfish and billfishes
Tables Tables-61 

Table 4-30 Seasonal and/or Area Closures to Commercial Fishing in Federal Waters Offshore the Mid-Atlantic 

and South Atlantic States (continued) 

Closed or Restricted Area Location Season Gear Restrictions or 

Protection Measures Reason/Purpose 

Mid-Atlantic Shark Area Offshore Oregon Inlet, 

NC and Cape Fear, NC January 1-July 31 

No bottom longline 

and shark gillnet 

gear 

Protect juvenile sharks 

and prohibited sharks 

Carl N. Schuster Jr. 

Horseshoe Crab Reserve 

Offshore DE, MD, and 

VA Year-round 

No trawl nets, pound 

nets, gillnets, or fyke 

nets 

Protect horseshoe crab 

spawning population 

and maintain crab eggs 

for migratory 

shorebirds 

South Atlantic shrimp 

cold weather closure 

Offshore NC, SC, GA, 

and FL 

In winter during 

severe cold weather, 

when adjacent South 

Atlantic states close 

all or part of their 

waters to shrimp 

trawling 

No trawling for 

brown, pink, or 

white shrimps 

Protect shrimp 

populations depleted by 

severe cold weather 

Golden crab trap closed 

areas 

Southeastern U.S. 

(divided into Northern, 

Middle, and Southern 

zones) 

Year-round 

Vessel size 

restrictions; permits 

limit a vessel to a 

particular zone 

Protect golden crab 

from overfishing 

Atlantic Large Whale 

Take Reduction Plan 

Entire U.S. east coast 

(divided into several 

subareas) 

September 1-May 31 

from 32° N to 

northern edge of 

Area of Interest; 

November 15-

April 15 from 

29°-32° N; 

December 1-March 

31 from 29° N to 

southern edge of 

Area of Interest 

Restrictions on 

trap/pot and gillnet 

use 

Protect large whales 

from entanglement 

Abbreviations: EEZ = Economic Exclusion Zone; HAPCs = Habitat Areas of Particular Concern; MPA = Marine 

Protected Areas; SMZs = Special Management Zones. 

Adapted from USDOC, NMFS, 2010d; 50 CFR 622.35. 
Tables-62 Atlantic G&G Programmatic EIS 

Table 4-31 

 

Partial List of Recreational Fishing Tournaments within the Area of Interest 

State Fishing Tournament Tournament Dates 

Delaware 

Delaware Sport Fishing Tournament 

Annual Delaware Black Drum Tournament 

Annual Summer Flounder Tournament 

Annual Rocktober Fishing Tournament and Festival 

Turkey Week Striper Tournament 

1 January–31 December 

22 April–1 June 

1 June –1 September 

19-21 October 

20-26 November 

Maryland 

Annual Opening Day Rockfish Tournament 

Flounder Frenzy 

Mako Mania Tournament 

World’s Largest Fishing Tournament: Maryland Fishing 

Challenge (1 Year Challenge) 

Harbor Tackle Annual Red Drum Tournament 

Annual Surf Fishing Tournament 

Harbor Tackle Annual Assateague Striper Tournament 

16 April 

18-19 May 

3-5 June 

7 September– 6 September 

23-25 September 

20-22 October 

19-20 November 

Virginia 

Virginia Saltwater Fishing Tournament 

Virginia Beach Rockfish Frostbite Challenge 

Triple Threat Tournament 

Croaker Fishing Tournament 

Virginia Beach Tuna Tournament 

The Annual Colonial Beach Rockfish Tournament 

1 January −31 December 

15-18 January 

14 April–30 August 

4 June 

11-14 July 

31 October – 2 November 

North Carolina 

Annual Hatteras Village Offshore Open 

Guiseppe Giaimo Scholarship Tournament 

Big Rock Blue Marlin 

Cape Fear Blue Marlin Fishing Tournament 

Bay Creek Classic 

U.S. Open King Mackerel Tournament 

The Wahoo Challenge 

Annual Davis Island Fishing Foundation Surf Fishing Tournament

Manteo Rotary Rockfish Rodeo 

12-15 May 

17 May 

10-18 June 

1-4 July 

September 26 

30 September–2 October 

13-16 October 

14-16 October 

3-4 December 

South Carolina 

Charleston Trident Fishing Tournament 

Bohicket Marina Invitational Billfish Tournament 

Annual Spring King Mackerel Tournament 

Carolina Billfish Classic 

Annual Fall King Mackerel Tournament 

Charleston Trident Fishing Tournament 

1 January 

11-14 May 

11-12 June 

22-25 May 

16-18 September 

1 December 

Georgia 

Annual King Mackerel Tournament 

Blue Water Tournament 

Kingfish/General Tournament 

General Tournament 

General Tournament 

13-16 May 

17-20 June 

7 August 

18 September 

16 October 

Florida 

Jacksonville Offshore Sport Fishing Club’s Tournament 

IFA Redfish Tour 

The Halifax Sport Fishing Club’s Annual Offshore Challenge 

Metro PCS Saltwater Classic 

Invitational Bluewater Tournament 

Fountain Mercury Kingbuster 

AT&T Greater Jacksonville Kingfish Tournament and Festival 

El Pescado Billfish Tournament 

The Halifax Sport Fishing Club’s Surf Fishing Tournament 

26 February 

5-6 March 

8-10 April 

6-7 May 

16-21 May 

10-13 June 

22-24 July 

30 September–2 October 

13 November 

Sources: Caught the Skunk.com, 2011; Florida Sportsman, 2011; World Fishing Network, 2011. 
Tables Tables-63 

Table 4-32 

 

Selected Parks, Seashores, Recreation Areas, and Wildlife Refuges 

along the Mid-Atlantic and South Atlantic Coasts 

State Recreational Area 

Delaware 

Cape Henlopen State Park 

Delaware Seashore State Park 

Fenwick Island State Park 

Maryland Assateague State Park 

Assateague Island National Seashore 

Virginia 

Assateague Island National Seashore 

Chincoteague National Wildlife Refuge 

Fisherman Island National Wildlife Refuge 

Seashore State Park 

False Cape State Park 

North Carolina 

Wright Brothers National Memorial Park 

Cape Hatteras National Seashore 

Pea Island National Wildlife Refuge 

Cape Lookout National Seashore 

Fort Macon State Park 

Theodore Roosevelt Natural Area 

Hammocks Beach State Park 

Masonboro Island Coastal Reserve 

Freeman Park 

Fort Fisher State Recreation Area 

South Carolina 

Myrtle Beach State Park 

Huntingdon Beach State Park 

Baruch-North Island Preserve 

Edisto Beach State Park 

Hunting Island State Park 

Cape Roman National Wildlife Refuge 

Georgia 

Wassaw National Wildlife Refuge 

Blackbeard Island National Wildlife Refuge 

Wolf Island National Wildlife Refuge 

Wassaw National Wildlife Refuge 

Jekyll Island State Park 

Cumberland Island National Seashore 

Florida 

Fort Clinch State Park 

Amelia Island State Park 

Little Talbot Island State Park 

Anastasia State Park 

Washington Oaks Gardens State Park 

Gamble Rogers Memorial State Recreation Area 

North Peninsula State Park 

Canaveral National Seashore 

Jetty Park 
Tables-64 Atlantic G&G Programmatic EIS 

Table 4-33 

 

Types of Recreational Activities by Location in the Area of Interest 

and along the Mid-Atlantic and South Atlantic Coasts 

Location Recreational Activities 

Offshore waters 

(depths >30 m) 

Fishing 

Diving (very limited – e.g., Monitor National Marine Sanctuary) 

Wildlife viewing (e.g., whale watching, pelagic birdwatching) 

Nearshore waters 

(depths <30 m) 

Fishing 

Boating 

Diving (artificial reefs and wrecks; Gray’s Reef National Marine Sanctuary) 

Wildlife viewing (e.g., whale watching, pelagic birdwatching) 

Beaches 

Swimming, snorkeling, surfing, etc. 

Sunbathing 

Fishing 

Boating 

Wildlife viewing 

Camping (e.g., state parks and national seashores) 

Lagoons and embayments 

Swimming 

Fishing 

Boating 

Wildlife viewing 

Camping 

Other coastal areas 

Sightseeing 

Golf 

Bicycling 

Hiking 

Hunting 

Table 4-34 

 

Economic Contribution of Marine-Based Tourism and Recreation to State Economies in 2004 

State Employment Wages 

Marine Based Tourism and Recreation Sectors1

Delaware 12,997 $188,532,229 

Maryland 35,014 $566,771,344 

Virginia 46,827 $669,121,385 

North Carolina 31,933 $387,164,508 

South Carolina 38,301 $614,585,607 

Georgia 19,739 $299,828,309 

Florida 262,643 $4,668,917,536 

Share of State Economy2

Delaware 3.16% 1.08% 

Maryland 1.42% 0.54% 

Virginia 1.34% 0.47% 

North Carolina 0.85% 0.29% 

South Carolina 2.14% 1.08% 

Georgia 0.51% 0.21% 

Florida 3.52% 1.78% 

1 National Ocean Economics Program, 2004. 

2 Total employment and wages for States from the U.S. Department of Labor, Bureau of Labor Statistics, 2004. 
Tables Tables-65 

Table 4-35 

 

Economic Contribution of Leisure and Hospitality to Coastal Economies1

 in 2008 

State Employment Wages 

Leisure and Hospitality 

Delaware 40,869 $758,460,245 

Maryland 125,220 $2,465,284,222 

Virginia 116,989 $2,038,305,323 

North Carolina 43,518 $600,529,156 

South Carolina 83,648 $1,454,839,518 

Georgia 32,196 $531,105,248 

Florida 661,930 $14,042,229,011 

Share of Coastal County Economy 

Delaware 9.90% 3.86% 

Maryland 9.98% 4.17% 

Virginia 10.56% 3.81% 

North Carolina 14.58% 6.31% 

South Carolina 19.31% 9.83% 

Georgia 14.92% 6.66% 

Florida 11.81% 6.10% 

1 Economies of shoreline adjacent counties. 

Source: National Ocean Economics Program, 2008. 
Table 4-36 Summary of Federal, Partnership, Federal Fishery Management, and State Designated Marine Protected Areas L

in the National System of Marine Protected Areas Site State Managing Agency Type of Site1 Protection Focus2 Primary Conservation Focus 

R

NEARSHORE/OFFSHORE SITES National Marine Sanctuaries NOAA’s Monitor National Marine Sanctuary NC NMSP NMS Focal Resource Cultural Heritage 

Gray’s Reef National Marine Sanctuary GA NMSP NMS Ecosystem Natural Heritage 

Deepwater Marine Protected Areas (MPAs) Snowy Grouper Wreck MPA NC NMFS MPA Focal Resource Sustainable Production 

Northern South Carolina MPA SC NMFS MPA Focal Resource Sustainable Production Edisto MPA SC NMFS MPA Focal Resource Sustainable Production Charleston Deep Reef MPA SC NMFS MPA Focal Resource Sustainable Production Georgia MPA GA NMFS MPA Focal Resource Sustainable Production North Florida MPA FL NMFS MPA Focal Resource Sustainable Production 

Other Federal Fishery Management Areas Waters off New Jersey Closure DE NMFS FFMZ Focal Resource Natural Heritage 

Elephant Trunk Sea Scallop Closed Area DE/MD NMFS FFMZ Focal Resource Sustainable Production Carl N. Shuster, Jr. Horseshoe Crab Reserve DE/MD NMFS FFMZ Focal Resource Sustainable Production Other Northeast Gillnet Waters Area DE/MD/VA NMFS FFMZ Focal Resource Natural Heritage Offshore Trap/Pot Waters DE/MD/VA/NC NMFS FFMZ Focal Resource Natural Heritage Southern Nearshore Trap/Pot Waters DE/MD/VA/NC NMFS FFMZ Focal Resource Natural Heritage Mid-Atlantic Coastal Waters Area DE/MD/VA/NC NMFS FFMZ Focal Resource Natural Heritage Southern Mid-Atlantic Waters Closure Area DE/MD/VA/NC NMFS FFMZ Focal Resource Natural Heritage Mid-Atlantic Shark Area NC NMFS FFMZ Focal Resource Sustainable Production Flynet Closure NC NMFS FFMZ Focal Resource Sustainable Production Charleston Bump Closed Area NC/SC/GA NMFS FFMZ Focal Resource Sustainable Production Southeast U.S. Restricted Area GA/FL NMFS FFMZ Focal Resource Natural Heritage Oculina Bank Habitat Area of Particular Concern FL NMFS HAPC Ecosystem Sustainable Production East Florida Coast Closed Area FL NMFS FFMZ Focal Resource Sustainable Production 
Table 4-36 Summary of Federal, Partnership, Federal Fishery Management, and State Designated Marine Protected Areas Listed in th

Marine Protected Areas (continued) Site State Managing Agency Type of Site1 Protection Focus2 Primary Conservation Focus 

R

COASTAL SITES National Park System Assateague Island National Seashore VA NPS NS Ecosystem Natural Heritage 

Cape Hatteras National Seashore NC NPS NS Ecosystem Natural Heritage Cape Lookout National Seashore NC NPS NS Ecosystem Natural Heritage Cumberland Island National Seashore GA NPS NS Ecosystem Natural Heritage Canaveral National Seashore FL NPS NS Ecosystem Natural Heritage 

National Wildlife Refuges Chincoteague National Wildlife Refuge VA USFWS NWR Ecosystem Natural Heritage 

Fisherman Island National Wildlife Refuge VA USFWS NWR Ecosystem Natural Heritage Back Bay National Wildlife Refuge VA USFWS NWR Ecosystem Natural Heritage Currituck National Wildlife Refuge NC USFWS NWR Ecosystem Natural Heritage Pea Island National Wildlife Refuge NC USFWS NWR Ecosystem Natural Heritage Cape Roman National Wildlife Refuge SC USFWS NWR Ecosystem Natural Heritage Blackbeard Island National Wildlife Refuge GA USFWS NWR Ecosystem Natural Heritage Wassaw National Wildlife Refuge GA USFWS NWR Ecosystem Natural Heritage Merritt Island National Wildlife Refuge FL USFWS NWR Focal Resource Natural Heritage Archie Carr National Wildlife Refuge FL USFWS NWR Focal Resource Natural Heritage 

National Estuarine Research Reserves Guana Tolomato Matanzas National Estuarine Research Reserve FL FDEP/ NOAA NERR Ecosystem Natural Heritage State Designated MPAs Cape Henlopen State Park DE DDNREC SP Ecosystem Natural Heritage 

Blue Crab Sanctuary VA VMRC Sanctuary Focal Resource Sustainable Production Wreck Island Natural Area Preserve VA VDCR NA Ecosystem Natural Heritage Sea Turtle Sanctuary NC NCDENR Sanctuary Focal Resource Natural Heritage Oregon Inlet Crab Spawning Sanctuary NC NCDENR Sanctuary Focal Resource Natural Heritage Hatteras Inlet Crab Spawning Sanctuary NC NCDENR Sanctuary Focal Resource Natural Heritage Ocracoke Inlet Crab Spawning Sanctuary NC NCDENR Sanctuary Focal Resource Natural Heritage Drum Inlet Crab Spawning Sanctuary NC NCDENR Sanctuary Focal Resource Natural Heritage Bardens Inlet Crab Spawning Sanctuary NC NCDENR Sanctuary Focal Resource Natural Heritage Fort Macon State Park NC NCDENR SP Ecosystem Cultural Heritage 
Table 4-36 Summary of Federal, Partnership, Federal Fishery Management, and State Designated Marine Protected Areas Listed 

Marine Protected Areas (continued) Site State Managing Agency Type of Site1 Protection Focus2 Primary Conservation Focus 

R

Fort Macon State Park Dedicated Nature Preserve NC NCDENR DNP Ecosystem Natural Heritage Masonboro Island Estuarine Reserve Dedicated Nature Preserve NC NCDENR DNP Ecosystem Natural Heritage Currituck Banks Estuarine Reserve Dedicated Nature Preserve NC NCDENR DNP Ecosystem Natural Heritage Currituck Outer Banks Preserve Dedicated Nature Preserve NC NCDENR DNP Ecosystem Natural Heritage Zekes Island Estuarine Reserve Dedicated Nature Preserve NC NCDENR DNP Ecosystem Natural Heritage Neuse-Southeast Pamlico Sound Area Outstanding Resource Water NC NCDENR ORW Ecosystem Natural Heritage Core Sound, Neuse River Basin Outstanding Resource Water NC NCDENR ORW Ecosystem Natural Heritage Topsail Sound and Middle Sound Area Outstanding Resource Water NC NCDENR ORW Ecosystem Natural Heritage Pamlico Sound Mechanical Harvesting of Oysters Prohibited Area NC NCDENR PA Focal Resource Natural Heritage Trawl Nets Prohibited Areas NC NCDENR PAs Focal Resource Natural Heritage Core Sound Mechanical Harvesting of Oysters Prohibited Area NC NCDENR PA Focal Resource Natural Heritage South of Onslow County Mechanical Harvesting of Oysters Prohibited Area NC NCDENR PA Focal Resource Natural Heritage Queen Anne's Revenge NC NCDCR Historic Site Focal Resource Cultural Heritage USS Huron Historic Shipwreck Preserve NC NCDCR Historic Site Focal Resource Cultural Heritage False Cape State Park SC SCDCR SP Ecosystem Natural Heritage Tom Yawkee Wildlife Center SC SCDNR Wildlife Center Focal Resource Natural Heritage Pelican Spit Natural Area GA GDNR NA Ecosystem Natural Heritage St. Catherines Bar Natural Area GA GDNR NA Ecosystem Natural Heritage Egg Island Bar Natural Area GA GDNR NA Ecosystem Natural Heritage Ossabaw Island Wildlife Management Area GA GDNR WMA Ecosystem Natural Heritage 
Table 4-36 Summary of Federal, Partnership, Federal Fishery Management, and State Designated Marine Protected Areas Listed in th

Marine Protected Areas (continued) Big Talbot Island State Park FL FDEP SP Ecosystem Natural Heritage 

Anastasia State Park FL FDEP SP Ecosystem Natural Heritage Fort Clinch State Park Aquatic Preserve FL FDEP AP Ecosystem Cultural Heritage Guana River Marsh Aquatic Preserve FL FDEP AP Ecosystem Natural Heritage Nassau River - St. Johns River Marshes Aquatic Preserve FL FDEP AP Ecosystem Natural Heritage Anastasia State Park Outstanding Florida Water FL FDEP OFW Ecosystem Natural Heritage Big Talbot Island State Park Outstanding Florida Water FL FDEP OFW Ecosystem Natural Heritage Canaveral National Seashore Outstanding Florida Water FL FDEP OFW Ecosystem Natural Heritage Fort Clinch State Park Aquatic Preserve Outstanding Florida Water FL FDEP OFW Ecosystem Natural Heritage Guana River Marsh Aquatic Preserve Outstanding Florida Water FL FDEP OFW Ecosystem Natural Heritage Little Talbot Island State Park Outstanding Florida Water FL FDEP OFW Ecosystem Natural Heritage Merritt Island National Wildlife Refuge Outstanding Florida Water FL FDEP OFW Ecosystem Natural Heritage Nassau River-St. Johns River Marshes Aquatic Preserve Outstanding Florida Water FL FDEP OFW Ecosystem Natural Heritage Timucuan Ecological and Historic Preserve Outstanding Florida Water FL FDEP OFW Ecosystem Natural Heritage 

Abbreviations: DDNREC = Delaware Department of Natural Resources and Environmental Control; FDEP = Florida Departm

Protection; FFMZ = Federal Fishery Management Zone; FT/ESPA = Federal Threatened/Endangered Species Protected AreDepartment of Natural Resources; NCDCR = North Carolina Department of Cultural Resources; NCDENR = North Carolina Depar

and Natural Resources; NERR = National Estuarine Research Reserve; NM = National Monument; NMFS = National Marine Fish

National Marine Sanctuary; NOAA = National Oceanic and Atmospheric Administration; NP = National Park; NPS = NationaNational Seashore; NWR = National Wildlife Refuge; SCDNR = South Carolina Department of Natural Resources; SFWS = UService; USDOI = U.S. Department of the Interior; VDCR = Virginia Department of Conservation and Recreation; VMRC =VirgCommission. 1 Type of Site: AP = Aquatic Preserve; DNP = Dedicated Nature Preserve; FFMZ = Federal Fishery Management Areas; MPA = M

NA = Natural Area; NERR = National Estuarine Research Reserve; NMS = National Marine Sanctuary; NS = National Seasho

Wildlife Refuge; OFW = Outstanding Florida Water; ORW = Outstanding Resource Water; PA = Prohibited Areas; SP = State Pa

Management Area. 
Table 4-36 Summary of Federal, Partnership, Federal Fishery Management, and State Designated Marine Protected Areas Listed 

Marine Protected Areas (continued)

2 Protection Focus:

Ecosystem: MPAs or zones whose legal authorities and management measures are intended to protect all of the components and p

within its boundaries. Examples: Ecosystem-scale MPAs include most marine sanctuaries, national parks and national monumentsFocal Resource: MPAs or zones whose legal authorities and management measures specifically target a particular habitat, s

resource (either natural or cultural). Examples: Focal-resource MPAs include many fisheries and cultural resource sites, includ

refuges and marine sanctuaries. 3 Fishing Restrictions: A = Restrictions Unknown; B = No Site Restrictions; C = Commercial and Recreational Fishing Restricted

Prohibited and Recreational Fishing Restricted; E = Commercial and Recreational Fishing Prohibited; F = Commercial Fishing Pro

Fishing Restricted; H = Commercial Fishing Restricted. 

Source: USDOC, NOAA, National Marine Protected Areas Center (http://www.mpa.gov). 
Tables Tables-71 

Table 4-37 

 

Population of the Metropolitan Statistical Areas Associated with Five Atlantic Coast Ports in 2000 and 2010 

Port Metropolitan Statistical Area Population 

2000 

Population 

2010 

Growth 

(%) 

Virginia Virginia Beach-Norfolk-Newport News 1,569,541 1,671,683 6.51 

Wilmington Wilmington 233,450 362,315 55.20 

Charleston Charleston-North Charleston-Summerville 549,033 664,607 21.05 

Savannah Savannah 293,000 347,611 18.64 

Jacksonville Jacksonville 1,100,491 1,345,596 22.27 

Source: U.S. Census Bureau, 2011. 

Table 4-38 

 

Gross Domestic Product (GDP) of the Metropolitan Statistical Areas Associated 

with Five Atlantic Coast Ports in 2009 

Port Metropolitan Statistical Area GDP 

($ millions) 

GDP per 

Capita ($)1

Real GDP per 

Capita Growth, 

2001-20092 

(%) 

Virginia Virginia Beach-Norfolk-Newport News 79,600 47,617 12.02 

Wilmington Wilmington 13,170 36,350 -13.40 

Charleston Charleston-North Charleston-Summerville 26,691 40,161 2.64 

Savannah Savannah 12,921 37,171 -1.65 

Jacksonville Jacksonville 58,303 43,329 1.44 

1

 Calculated by dividing GDP by the population shown in Table 4-33. 2 In 2005 dollars. 

Source: USDOC, Bureau of Economic Analysis, 2011. 

Table 4-39 

 

Labor Force and Unemployment in the Metropolitan Statistical Areas Associated 

with Five Atlantic Coast Ports in January 2011 

Port Metropolitan Statistical Area Labor Force 

(thousands) 

Unemployment 

Rate 

(%) 

Unemployed 

(thousands) 

Virginia Virginia Beach-Norfolk-Newport News 813.5 7.6 61.8 

Wilmington Wilmington 172.3 10.6 18.3 

Charleston Charleston-North Charleston-Summerville 317.9 8.3 26.3 

Savannah Savannah 174.7 9.2 16.1 

Jacksonville Jacksonville 679.9 11.5 78.4 

Source: U.S. Department of Labor, Bureau of Labor Statistics, 2011. 
Table 4-40 Minority Presence in Metropolitan Statistical Areas Associated with Five Atlantic Coast Ports in 2010, Compared with State and 

Percent of Total Population Location Total Population White Black or African American Alaska Native or American Indian Asian Native Hawaiian and Other Pacific Islander Some Other Race Alone Two or More Races 

United States 308,745,538 72.41 12.61 0.95 4.75 0.17 6.19 2.92 Virginia (statewide) 8,001,024 68.58 19.39 0.37 5.50 0.07 3.18 2.92 Virginia Beach-Norfolk- Newport News, VA-NC MSA 1,671,683 59.65 31.25 0.41 3.47 0.12 1.67 3.43 North Carolina (statewide) 9,535,483 68.47 21.48 1.28 2.19 0.07 4.34 2.16 Wilmington, NC MSA 362,315 79.83 14.21 0.57 0.88 0.05 2.55 1.91 South Carolina (statewide) 4,625,364 66.16 27.90 0.42 1.28 0.06 2.45 1.73 Charleston-North Charleston-Summerville, SC MSA 664,607 65.57 27.69 0.46 1.63 0.09 2.47 2.09 Georgia (statewide) 9,687,653 59.74 30.46 0.33 3.25 0.07 4.01 2.14 Savannah, GA MSA 347,611 59.68 33.87 0.27 2.08 0.09 1.88 2.14 Florida (statewide) 18,801,310 75.04 15.96 0.38 2.42 0.07 3.62 2.51 Jacksonville, FL MSA 1,345,596 69.89 21.77 0.39 3.43 0.09 1.82 2.62 

1 Individuals who identify themselves as Hispanic, Latino, or Spanish might be of any race; the sum of the other percentages und

Population” columns plus the “Hispanic or Latino” column therefore does not equal 100%. 2 The total minority population, for the purposes of this analysis, is the total population minus the non-Latino/Spanish/Hispanic white p

Source: U.S. Census Bureau, 2011. 
Tables Tables-73

Table 4-41 

 

Low-Income Presence in Metropolitan Statistical Areas Associated with Five Atlantic Coast Ports in 2009, 

Compared with State and National Averages 

Location Total 

Population1

Low-Income 

Population 

Share 

(%) 

United States 299,026,555 42,868,163 14.34 

Virginia (statewide) 7,623,736 802,578 10.53 

Virginia Beach-Norfolk-Newport News, VA-NC MSA 1,621,837 167,507 10.33 

North Carolina (statewide) 9,095,948 1,478,214 16.25 

Wilmington, NC MSA 346,425 56,481 16.30 

South Carolina (statewide) 4,416,859 753,739 17.07 

Charleston-North Charleston-Summerville, SC MSA 642,921 100,217 15.59 

Georgia (statewide) 9,535,714 1,574,649 16.51 

Savannah, GA MSA 334,330 47,805 14.30 

Florida (statewide) 18,124,789 2,707,925 14.94 

Jacksonville, FL MSA 1,305,970 176,188 13.49 

1

 Population for whom poverty status is determined. 

Source: U.S. Census Bureau, 2009. 
Table 4-42 Minority Presence in Fishing Communities in 2000 in States Adjacent to the Area of Interest Percent of Total Population Location Total Population White Black or African American Alaska Native or American Indian Asian Native Hawaiian and Other Pacific Islander Some Other Race Alone Two 

R

Delaware (statewide) 783,600 74.6 19.2 0.3 2.1 0.0 2.0 DE Fishing Communities 13,008 86.9 9.2 0.2 0.8 0.0 1.3 Maryland (statewide) 5,296,486 64.0 27.9 0.3 4.0 0.0 1.8 2MD Fishing Communities 38,556 79.1 18.5 0.3 0.4 0.0 0.3 Virginia (statewide) 7,078,515 72.3 19.6 0.3 3.7 0.1 2.0 2VA Fishing Communities 972,008 74.5 21.3 0.3 1.3 0.0 1.0 North Carolina (statewide) 8,049,313 72.1 21.6 1.2 1.4 0.0 2.3 NC Fishing Communities 21,930 79.5 17.3 0.3 0.6 0.0 1.3 South Carolina (statewide) 4,012,012 67.2 29.5 0.3 0.9 0.0 1.0 SC Fishing Communities 207,762 62.9 30.6 4.1 0.6 0.1 0.7 Georgia (statewide) 8,186,453 65.1 28.7 0.3 2.1 0.1 2.4 GA Fishing Communities 172,358 68.8 28.6 0.3 0.7 0.1 0.6 Florida (statewide) 15,982,378 78.0 14.6 0.3 1.7 0.1 3.0 2FL Fishing Communities 1,331,618 78.9 15.5 0.3 1.3 0.1 1.9 2

1 Individuals who identify themselves as Hispanic, Latino, or Spanish might be of any race; the sum of the other percentages under 

Population” columns plus the “Hispanic or Latino” column therefore does not equal 100%. Source: USDOC, NMFS, 2009c. 
Tables Tables-75 

Table 4-43 

 

Low-Income Presence in Fishing Communities in States Adjacent to the Area of Interest in 2000 

Location Percent of Family Households 

Below Poverty Level 

Delaware (statewide) 6.5 

Delaware Fishing Communities 1.7–10.6 

Maryland (statewide) 6.1 

Maryland Fishing Communities 1.9–30.5 

Virginia (statewide) 7.0 

Virginia Fishing Communities 1.1–17.1 

North Carolina (statewide) 9.0 

North Carolina Fishing Communities 0.0–27.9 

South Carolina (statewide) 10.7 

South Carolina Fishing Communities 3.2–19.9 

Georgia (statewide) 9.9 

Georgia Fishing Communities 0.0–25.2 

Florida (statewide) 9.0 

Florida Fishing Communities 2.3–25.4 

Note: Poverty rates vary considerably among fishing communities identified in each state. The ranges shown 

indicate the lowest and highest poverty rates among the identified fishing communities in each state. 

Source: USDOC, NMFS, 2009c. 
Tables-76 Atlantic G&G Programmatic EIS 

Table 5-1 

 

EFH Consultation Requirements and the Applicable Programmatic EIS Chapters 

EFH Assessment 

Critical Elements Chapters Chapter Titles 

Chapter 2 Alternatives Including the Proposed Action 

Chapter 3 G&G Activities and Proposed Action 

Scenario 

Chapter 3.2 Oil and Gas Development Surveys 

Chapter 3.3 Renewable Energy Resource Assessment 

and Site Characterization Surveys 

Description of the action 

Chapter 3.4 Marine Minerals Surveys 

Chapter 2 Alternatives Including the Proposed Action 

Chapter 4.2.5.1 Fish Resources and Essential Fish Habitat 

Description 

Chapter 4.2.5.2 Fish Resources and Essential Fish Habitat 

Impacts of Routine Events 

Chapter 4.2.5.3 Fish Resources and Essential Fish Habitat 

Impacts of Accidental Events 

Chapter 4.2.5.4 Fish Resources and Essential Fish Habitat 

Impacts of Cumulative Events 

An analysis of potential 

adverse effects on EFH and 

managed species 

Appendix A (to be provided 

under separate cover) Biological Assessment (for ESA) 

Chapter 4.2.5.1 Fish Resources and Essential Fish Habitat 

Description 

Chapter 4.2.5.2 Fish Resources and Essential Fish Habitat 

Impacts of Routine Events 

Chapter 4.2.5.3 Fish Resources and Essential Fish Habitat 

Impacts of Accidental Events 

Chapter 4.2.5.4 Fish Resources and Essential Fish Habitat 

Impacts of Cumulative Events 

Federal agency conclusions 

regarding the identified 

effects 

Appendix A (to be provided 

under separate cover) Biological Assessment (for ESA) 

Appendix A (to be provided 

under separate cover) Biological Assessment (for ESA) Mitigations plans (if 

applicable) Appendix C Existing Regulations, Protective Measures, 

and Mitigation 

Chapter 2 Alternatives Including the Proposed Action 

Appendix A (to be provided 

under separate cover) Additional information Biological Assessment (for ESA) 

Appendix J Fish Hearing and Sensitivity to Acoustic 

Impacts 
Tables Tables-77 

Table 5-2 

 

NMSA Consultation Requirements and the Applicable Programmatic EIS Chapters 

NMSA Discussion of Critical Elements Chapters Chapter Titles 

Chapter 2 Alternatives Including the Proposed Action 

Chapter 3 G&G Activities and Proposed Action 

Scenario 

Chapter 3.2 Oil and Gas Development Surveys 

Chapter 3.3 Renewable Energy Resource Assessment 

and Site Characterization Surveys 

Description of the action 

Chapter 3.4 Marine Mineral Surveys 

Chapter 2 Alternatives Including the Proposed Action 

Chapter 4.2.1 Benthic Communities 

Chapter 4.2.11.1 Marine Protected Areas Description 

Chapter 4.2.11.2 Marine Protected Areas Routine Events 

An analysis of potential adverse effects 

on NMSA 

Chapter 4.2.11.4 Marine Protected Areas Cumulative Events 

Chapter 4.2.11.1 Marine Protected Areas Description 

Chapter 4.2.11.2 Marine Protected Areas Routine Events Federal agency conclusions regarding 

the identified effects 

Chapter 4.2.11.4 Marine Protected Areas Cumulative Events 

Mitigations plans (if applicable) Appendix C Existing Regulations, Protective Measures, 

and Mitigation 

Additional information Chapter 2 Alternatives Including the Proposed Action 

APPENDIX A 

BIOLOGICAL ASSESSMENT

(TO BE INCLUDED IN FINAL PROGRAMMATIC EIS) 

APPENDIX B 

 

STATE COASTAL ZONE MANAGEMENT PROGRAMS

State Coastal Zone Management Programs B-iii

TABLE OF CONTENTS 

Page 

1. STATE OF DELAWARE’s COASTAL MANAGEMENT PROGRAM..........................................B-1

2. STATE OF MARYLAND’s COASTAL PROGRAM.......................................................................B-2

3. COMMONWEALTH OF VIRGINIA’s COASTAL ZONE MANAGEMENT PROGRAM............B-2

4. STATE OF NORTH CAROLINA’s COASTAL MANAGEMENT PROGRAM.............................B-3

5. STATE OF SOUTH CAROLINA’s COASTAL ZONE MANAGEMENT PROGRAM..................B-3

6. STATE OF GEORGIA’s COASTAL MANAGEMENT PROGRAM ..............................................B-4

7. STATE OF FLORIDA’s COASTAL MANAGEMENT PROGRAM...............................................B-5

8. REFERENCES CITED.......................................................................................................................B-6

State Coastal Zone Management Programs B-1

The Coastal Zone Management Act (CZMA) was established to develop comprehensive programs 

to manage and balance competing uses of and impacts to coastal resources. The CZMA emphasizes 

the primacy of State decision-making regarding the coastal zone preserve, protect, develop, and 

where possible, to restore or enhance, the resources of the Nation's coastal zone for this and 

succeeding generations; and to encourage and assist the States to exercise effectively their 

responsibilities in the coastal zone through the development and implementation of management 

programs to achieve wise use of the land and water resources of the coastal zone, giving full 

consideration to ecological, cultural, historic, and esthetic values as well as the needs for compatible 

economic development. In order to implement CZMA, each State has a Coastal Zone Management 

Program (CZMP) that is federally approved by National Oceanic and Atmospheric Administration 

(NOAA). These CZMPs are a comprehensive statement setting forth objectives, enforceable policies, and 

standards for public and private use of land and water resources and uses in that State's coastal zone. 

Federal consistency is the CZMA requirement where Federal agency activities that have reasonably 

foreseeable effects on any land or water use or natural resource of the coastal zone must be consistent to 

the maximum extent practicable with the enforceable policies of a coastal State’s federally approved 

coastal management program. The State requirements for Federal consistency review are based on the 

requirements of State statutes, CZMA regulations at 15 Code of Federal Regulations (CFR) 930, and 

U.S. Department of the Interior (USDOI) regulations at 30 CFR 250, 30 CFR 254, and 30 CFR 256. 

There are currently changes undertaken within the CZMA program regulations, and NOAA intends to 

replace the CZMA program change regulations, 15 CFR 923, subpart H, and the Office of Ocean and 

Coastal Resource Management’s (OCRM’s) Program Change Guidance (July 1996) with new regulations 

at 15 CFR 923, Subpart H (U.S. Department of Commerce [USDOC], NOAA, 2008). 

Each coastal State’s official coastal boundary can be identified from NOAA’s website 

(USDOC, NOAA, 2011). Federal agencies provide feedback to the States through each Section 312 

evaluation conducted by NOAA. 

A State’s approved CZMP may also provide for the State’s review of permits and license activities to 

determine whether they will be conducted in a manner consistent with the State’s CZMP. This review 

authority is applicable to activities conducted in any area that has been leased under the Outer Continental 

Shelf Lands Act (OCSLA) and that affect any land or water use or natural resource within the State’s 

coastal zone (16 United States Code [U.S.C.] 1456(c)(3)(B)). 

This section provides an overview of the CZMP within each state within the area of interest (AOI). 

1. STATE OF DELAWARE’S COASTAL MANAGEMENT PROGRAM 

Delaware’s Coastal Zone Act was passed in 1971 and provides to the Secretary of the Department of 

Natural Resources and Environmental Control (DNREC) and the Coastal Zone Industrial Control Board 

the authority to promulgate regulations to carry out the requirements contained within the Act. Delaware 

has defined its Coastal Management Area as the entire state for the purposes of the federally approved 

coastal management program. The management of Delaware’s coastal resources is shared by a number of 

entities within DNREC including the Delaware Coastal Management Program (DCMP) and the Delaware 

National Estuarine Research Reserve (DNERR). These programs help to preserve, protect, develop and 

enhance the state’s coastal resources and resolve conflicts related to coastal zone issues. Functions of the 

DCMP include management of coastal resources through research projects, education and grant programs, 

and policy development; administration of the Coastal Zone Federal Consistency Certification program; 

special area management planning; and providing technical assistance to State and local governments for 

local land use planning. The function of DNERR is to preserve and manage the natural resources within 

the Reserve and to promote informed coastal decision-making. 

In 2004, the DCP was responsible for the State’s Coastal and Estuarine Land Conservation Program 

(CELCP) development. The CELCP is a land acquisition program funded by NOAA that provides grants 

to eligible State agencies and local governments to acquire property or conservation easements from 

willing sellers within a State's coastal zone or coastal watershed boundary. 

The State of Delaware requires a detailed description and the coastal zone effects, objective, and 

schedule for all activities associated with a project; an analysis of the project’s likely coastal zone effects 

and a description of how it will comply with applicable Coastal Zone Management Policies; and an 

evaluation of the relevant enforceable policies of the DCMP. Supporting information can include copies 
B-2 Atlantic G&G Programmatic EIS 

of Federal permit applications, construction plans, environmental assessments or environmental impact 

statements, monitoring data, modeling data and verification of other permits received. A guide to the 

Delaware’s coastal consistency process can be found at DNREC’s website (DNREC, 2004). 

2. STATE OF MARYLAND’S COASTAL PROGRAM 

Maryland's Coastal Program, established by executive order and approved in 1978, is a network of 

State laws and policies designed to protect coastal and marine resources. Maryland's coastal zone 

includes 16 counties (Anne Arundel, Baltimore, Calvert, Caroline, Charles, Cecil, Dorchester, Harford, 

Kent, Prince George's, Queene Anne's, Somerset, St. Mary's, Talbot, Wicomico, Worcester), Baltimore 

City, the Chesapeake Bay, other coastal bays, and the boundary extends to the limit of Maryland's 

three-mile jurisdiction in the Atlantic Ocean. Through partnerships and funding to local governments, 

State agencies, non-profit organizations, and universities, the Coastal Program addresses a variety of 

coastal issues including provision of public access, nonpoint source pollution reduction, coastal hazards 

mitigation, habitat and living resources protection and growth management. 

The Department of Natural Resources (DNR) is the lead agency for the State’s CZMP. Within DNR, 

the Coastal Zone Management Division of the Watershed Services Unit is the lead agency for the CZMP. 

The Federal consistency requirements are carried out by the Coastal Zone Consistency Division in the 

Wetlands and Waterways Program of the Water Management Administration (WMA) in the Maryland 

Department of the Environment (MDE). WMA is responsible for coordinating the Federal consistency 

review with appropriate State agencies, consolidating the State’s comments, and forwarding the State’s 

response and decision to the appropriate applicant. Maryland does not require a separate CZM 

application for, but requires that applicants for actions including Outer Continental Shelf 

(OCS)-related permits or approvals must certify that their proposed activity will be conducted in a 

manner consistent with the State’s CZMP. Typically either the Federal permits and licenses or the Joint 

Federal/State Permit Application will be reviewed for consistency with the CZMP. The State’s permit 

authorization for permitted activities will include the required Federal consistency decision. A guide to 

Maryland’s coastal consistency program (Ghigiarelli, 2004) can be found at Maryland’s DNR website. 

3. COMMONWEALTH OF VIRGINIA’S COASTAL ZONE MANAGEMENT 

PROGRAM 

The Virginia CZMP was established in 1986 through an Executive Order to protect and manage 

Virginia's "coastal zone." The Program is a network of State agencies and local governments through 

which the coastal resources of Virginia are managed. The network consists of 13 State agencies and local 

governments including the Marine Resources Commission; Department of Environmental Quality Lead 

coordinating agency; Department of Game and Inland Fisheries; Department of Conservation and 

Recreation; Department of Health; Tidewater Cities and Counties; Department of Agriculture and 

Consumer Affairs; Department of Forestry; Department of Historic Resources; Department of Mines, 

Minerals and Energy; Department of Transportation; Economic Development Partnership; and the 

Virginia Institute of Marine Science. 

Virginia’s coastal zone encompasses 29 counties, 15 cities, and 42 incorporated towns and all of the 

waters therein, and out to, the three nautical mile Territorial Sea boundary, including all of Virginia's 

Atlantic coast watershed as well as parts of the Chesapeake Bay and Albemarle - Pamlico Sound 

watersheds. 

The Department of Environmental Quality (DEQ) serves as the lead agency for Virginia's networked 

coastal zone management program and helps agencies and localities to develop and implement 

coordinated coastal policies and solve coastal management problems while Coastal Policy Teams (CPTs) 

facilitate cooperation among the State agencies and local governments. The CPTs members represent all 

of Virginia's key CZM partners and provide a forum for discussion and resolution of cross-cutting coastal 

resource management issues. Virginia's eight coastal planning district commissions (PDCs) also 

participate in the implementation of the Virginia CZMP by providing a link between the State agencies 

and 87 localities that constitute Virginia's network of coastal resource managers. A representative from 

each PDC serves on the Virginia CZMP’s Coastal Policy Team. Virginia’s eight PDCs are AccomackNorthampton Planning District Commission, Crater Planning District Commission, Hampton Roads 
State Coastal Zone Management Programs B-3

Planning District Commission, Middle Peninsula Planning District Commission, Northern Neck Planning 

District Commission, Northern Virginia Regional Commission, George Washington Regional 

Commission, and Richmond Regional Planning District Commission. 

For Federal consistency review, Virginia requires an adequate description including aspects of the 

project that may cause direct or indirect environmental impacts, objective, and schedule for all activities 

associated with a project; an evaluation that includes a set of findings relating to the probable coastal 

effects of the proposed project and its associated facilities to the relevant enforceable policies of the 

Virginia CZMP. Further information on the Virginia consistency determination process may be found at 

DEQ’s website (DEQ, 2011). 

4. STATE OF NORTH CAROLINA’S COASTAL MANAGEMENT 

PROGRAM 

The North Carolina Coastal Area Management Act (CAMA) was created in 1974. The CAMA 

established the Coastal Resources Commission (CRC), required local land use planning in 20 coastal 

counties, and provided for a program for regulating development. The North Carolina Coastal 

Management Program was federally approved in 1978. The CRC administers the CAMA, establishes 

policies for the North Carolina Coastal Management Program, and adopts implementing rules for both 

CAMA and the North Carolina Dredge and Fill Act. The commission also designates areas of 

environmental concern, adopts rules and policies for coastal development within those areas, and certifies 

local land-use plans. As a part of this program, the CRC designated "Areas of Environmental Concern" 

within the 20 coastal counties and set rules for managing development within these areas. 

The Division of Coastal Management (DCM), in the Department of Environment and Natural 

Resources, provides staffing services to the CRC, implements CRC rules, and issues CAMA permits. 

DCM is the lead agency of the North Carolina Coastal Management Program and implements and 

supervises all the various CZMPs in the state. North Carolina's coastal zone includes 20 coastal counties 

(Beaufort, Hertford, Bertie, Hyde, Brunswick, New Hanover, Camden, Onslow, Carteret, Pamlico, 

Chowan, Pasquotank, Craven, Pender, Currituck, Perquimans, Dare, Tyrrell, Gates, Washington) that in 

whole or in part are adjacent to, adjoining, intersected or bounded by the Atlantic Ocean. 

The consistency review process can be divided into two classifications, one for Federal activities and 

the other for non-Federal projects that require a Federal permit and/or license. For non-Federal projects, a 

Consistency Certification document must be submitted that demonstrates how the proposed project would 

be considered consistent with the State’s Coastal program. The procedures for making this submission 

are contained in Subpart “D” of 15 CFR 930 and further information on the North Carolina CZM process 

can be found at the North Carolina Department of Environment and Natural Resources website

(NCDENR, 2010). 

For Federal consistency, any project must comply with the key elements of North Carolina's Coastal 

Management Program such as the CAMA, the State's Dredge and Fill Law, Chapter 7 of Title 15A of 

North Carolina's Administrative Code, regulations passed by the CRC, and local land use plans certified 

by the CRC. 

5. STATE OF SOUTH CAROLINA’S COASTAL ZONE MANAGEMENT 

PROGRAM 

The South Carolina CZMP was established under the guidelines of the national Coastal Zone 

Management Act (1972) as a State-Federal partnership to comprehensively manage coastal resources. It 

was authorized in 1977 under South Carolina’s Coastal Tidelands and Wetlands Act (CTWA) (S.C. Code 

Ann. Section 48-39-10 et seq.) with the goal of achieving balance between the appropriate use, 

development, and conservation of coastal resources in the best interest of all citizens of the state. 

The South Carolina Coastal Program established a permanent South Carolina Coastal Council 

(SCCC); provided for the development and administration of a comprehensive Coastal Management 

Program; set up a permitting process for activities occurring in the four "critical areas" of the coastal zone 

(tidelands, coastal waters, beaches and. primary ocean-front sand dunes); and provided a mechanism for 

State and local agency consistency with the State's approved Coastal Management Program throughout 

the coastal zone. 
B-4 Atlantic G&G Programmatic EIS 

The South Carolina Department of Health and Environmental Control Office of Ocean and Coastal 

Resource Management (DHEC-OCRM) is the designated State coastal management agency and is 

responsible for implementing the approved South Carolina CZMP through the authorities specified in the 

Coastal Tidelands and Wetlands Act (SC Code ann. §48-39-110 et. seq.); the DHEC Coastal Division 

Regulations and the enforceable policies of the South Carolina Coastal Program Document. 

The DHEC-OCRM has direct permitting authority for proposed activities within the “critical areas” 

of the coast. The DHEC-OCRM also has broader management authority over activities within the 

eight-county Coastal Zone (Beaufort, Berkeley, Charleston, Colleton, Dorchester, Horry, Jasper, and 

Georgetown) through consistency certification of both Federal and State permits, Federal licenses, and 

requests for funding assistance. The "critical areas" receive more intensive attention through a direct 

permitting system while the remainder of the coastal zone is managed through cooperation with other 

State and local agencies. 

The burden of implementing the South Carolina Coastal Management Program rests not only with the 

Coastal Council but also with all other State and local agencies and commissions. Seventeen State 

agencies, including the Archeology Institute; South Carolina Department of Health and Environmental 

Control; South Carolina Department of Parks, Recreation, and Tourism; South Carolina Forestry 

Commission; South Carolina Land Resources Conservation Commission; South Carolina State Ports 

Authority; South Carolina Water Resources Commission; and the South Carolina Wildlife &Marine 

Resources Department, exercise authority over the use of coastal resources, specific areas in the coastal 

zone, or activities in the coastal zone. Memoranda of Agreement are used to effectively coordinate all 

State agency activities with the Coastal Management Program. 

South Carolina requires an detailed description of the proposed activities and their associated 

facilities, objective, and schedule for all activities associated with a project; a brief assessment relating the 

probable coastal zone effects of the activities; and specific information on onshore support base, support 

vessels, shallow hazards, oil-spill response, wastes and discharges, transportation activities, and air 

emissions; and all relevant State and/or local government permits. 

6. STATE OF GEORGIA’S COASTAL MANAGEMENT PROGRAM 

In 1992, the State of Georgia initiated the development of the Georgia Coastal Management Program 

(GCMP). The Georgia General Assembly authorized the GCMP with the passage of the Georgia Coastal 

Management Act (O.C.G.A.12-5-320 et. seq.) in April 1997, and designated the Georgia Department of 

Natural Resources (DNR), Coastal Resources Division as the lead agency for administering the GCMP. 

NOAA subsequently approved the Program in January 1998, at which time Georgia became the 32nd state 

participating in the National CZMP. 

In 1992 the GCMP was advised by a 25-member Coastal Zone Advisory Committee appointed by the 

Governor of Georgia. The Committee was made up of a diverse cross-section of the coastal Georgia 

citizenry with the goal of providing public input throughout the development of the GCMP. In 1994, a 

new Coastal Advisory Committee was appointed by the Commissioner of the Department of Natural 

Resources to review the draft Program Document, to assist with public education throughout the program 

development process, and to provide technical assistance. In 1997, the committee was expanded to 

increase participation from interested local governments. Finally, in 2003, the Committee was revamped 

and reauthorized by the Commissioner of DNR as the Coastal Advisory Council with by-laws and an 

appointed membership. The Council is charged with developing annual themes and funding criteria for 

the Coastal Incentive Grant Program, and providing a communication loop between the CZMP and 

coastal citizens. 

The GCMP consists of 33 State codes, which constitute the enforceable policies and is administered 

by the Department of Natural Resources, Coastal Resources Division. The Program works with coastal 

local governments and other State and Federal agencies to enhance service to the public, increase 

coordination and communication, provide assistance with the Program, among its many other activities. 

The Program also implements the Georgia Coastal Marshlands Protection Act (O.C.G.A.12-5-280), Shore 

Protection Act (O.C.G.A.12-5-230), and Revocable License Program (O.C.G.A. 50-16-61). 

For effective coastal management, the GCMP encompasses all tidally influenced water bodies and all 

areas economically tied to coastal resources including such industries as shrimping, crabbing, recreational 

fishing, tourism, shipping, and manufacturing. The GCMP’s service area includes the following 
State Coastal Zone Management Programs B-5

11 counties: Brantley, Bryan, Camden, Charlton, Chatham, Effingham, Glynn, Liberty, Long, McIntosh, 

and Wayne. Within the 11 counties, all waters of the state including the coastal ocean to the limit of the 

state jurisdiction (3 nautical miles), and all submerged lands are part of the coastal area. 

As lead agency for the GCMP, the Coastal Resources Division (CRD) conducts several functions 

including resource management, ecological monitoring, permitting, technical assistance (such as Best 

Management Practices), and Federal consistency review. Additional activities covered by the program 

include Outreach and Education, Coastal Nonpoint Source (6217) Program, and Coastal Incentive Grants. 

Local, State, and Federal agencies perform their respective functions in accordance with the GCMP and 

coordinated with the DNR. In addition, research institutes and other organizations assist in information 

gathering and analysis with coastal resource issues. 

Activities implemented through the Coastal Management Network are divided into Local 

Governments, State Agencies, and Federal Agencies. Local governments assist in long-term planning, 

economic development, and natural resource protection through preparation and implementation of their 

respective comprehensive plans, local laws, and zoning regulations, as well as through their chambers of 

commerce and economic development authorities. State agencies continue to administer their respective 

coastal management efforts as defined by existing Georgia State law. Memoranda of Agreement between 

the CRD and other State agencies with regulatory authority in the coastal area help ensure that all 

agencies act in accordance with the policies of the GCMP. State agencies involved in the GCMP include 

the CRD; Department of Community Affairs; Department of Human Resources; Environmental 

Protection Division; Georgia Department of Transportation; Georgia Forestry Commission; Georgia Ports 

Authority; Historic Preservation Division; Jekyll Island Authority; Office of the Secretary of State, Parks, 

Recreation; and Historic Sites Division; Public Service Commission, and Wildlife Resources Division. 

Federal agencies continue to administer their respective programs as they are renewed for consistency 

with the GCMP. The following Federal agencies are involved in the GCMP: Army Corps of Engineers; 

Bureau of Lands Management; Coast Guard; Department of Agriculture; Department of Defense; 

Environmental Protection Agency; Federal Aviation Administration; Federal Emergency Management 

Agency; Federal Energy Regulatory Commission; Federal Highway Administration; Federal Law 

Enforcement Training Center; Fish and Wildlife Service; General Services Administration; General 

Services Administration; Bureau of Ocean Energy Management (BOEM); National Park Service; and 

Nuclear Regulatory Commission. 

For Federal consistency review, the State of Georgia requires a detailed description of the proposed 

activity, its expected effects upon the land or water uses or natural resources of Georgia's coastal zone, 

and an evaluation of the proposed activity in light of applicable enforceable policies. 

7. STATE OF FLORIDA’S COASTAL MANAGEMENT PROGRAM 

For purposes of the CZMA, the State of Florida’s coastal zone includes the area encompassed by the 

State’s 67 counties and its territorial seas. Lands owned by the Federal Government and the Seminole 

and Miccosukee Indian tribes are not included in the State’s coastal zone; however, Federal activities in 

or outside the coastal zone, including those on Federal or tribal lands, that affect any land or water or 

natural resource of the State’s coastal zone are subject to review by Florida under the CZMA. The 

Florida Coastal Management Act, codified as Chapter 380, Part II, Florida Statutes, authorized the 

development of a coastal management program. In 1981 the Florida Coastal Management Program 

(FCMP) was approved by NOAA. 

The policies identified by the State of Florida as being enforceable in the FCMP are the 23 chapters 

that NOAA approved for incorporation in the State’s program. The 2005 Florida Statutes are the most 

recent version approved by NOAA and include the listing of OCSLA permits under Subpart E; and the 

addition of draft Environmental Assessments and Environmental Impact Statements as necessary data and 

information for Federal consistency review. 

A network of eight State agencies and five regional water management districts implement the 

FCMP’s 24 statutes. The water management districts are responsible for water quantity and quality 

throughout the State’s watersheds. The State agencies include the Department of Environmental 

Protection (DEP), the lead agency for the FCMP and the State’s chief environmental regulatory agency 

and steward of its natural resources; the Florida Department of Agriculture and Consumer Affairs 

(DACS), which is responsible for hydrologic restoration and development of best management practices 
B-6 Atlantic G&G Programmatic EIS 

for water quality and water conservation among other responsibilities; Florida Department of 

Community Affairs (DCA), which serves as the State’s land planning and emergency management 

agency; the Department of Health (DOH), which, among other responsibilities, regulates on-site sewage 

disposal; the Department of State (DOS), Division of Historical Resources, which protects historic and 

archaeological resources; the Fish and Wildlife Conservation Commission (FWCC), which protects and 

regulates fresh and saltwater fisheries, marine mammals, and birds and upland species, including 

protected species and the habitat used by these species; the Department of Transportation (DOT), which is 

charged with the development, maintenance, and protection of the transportation system; Florida Division 

of Emergency Management (DEM), which ensures that Florida is prepared to respond to emergencies 

caused by a wide variety of threats, recover from disasters, mitigate disaster impacts, and reduce or 

eliminate long-term risk to human life and property; and the Governor’s Office of Planning and Budget, 

which plays a role in the comprehensive planning process. Some of these agencies are currently being 

reorganized and will be combined or modified, including the DCA and DEM, which will cease to exist. 

Instead, the DCA responsibilities will become part of the new Department of Economic Opportunity and 

the DEM will move to the Executive Office of the Governor. 

The DEP is designated as the lead agency for the FCMP pursuant to the CZMA 14. The DEP’s 

Office of Intergovernmental Programs, is charged with overseeing the State’s coastal management 

program and coordinates the review of OCS plans with FCMP member agencies to ensure that the plan is 

consistent with applicable State enforceable policies and the Governor’s responsibilities under the Act. 

The OCS is a jurisdictional term used to describe those submerged lands (sea bed and subsoil) that lie 

seaward of State water boundaries (3 nautical miles off the east coast). An OCS plan is any plan for 

offshore exploration; development of oil, natural gas, and other mineral resources; or production activity 

that is conducted in any area leased under the OCSLA. The Federal government manages natural 

resources on the OCS, while the States manage the resources directly off their coasts. 

The State of Florida requires an adequate description, objective, and schedule for all activities 

associated with a project; specific information on the natural resources potentially affected by the 

proposed activities; and specific information on onshore support base, support vessels, shallow hazards, 

oil-spill response, wastes and discharges, transportation activities, and air emissions; and a Federal 

consistency certification, assessment, and findings. As identified by the State of Florida, the 

State-enforceable policies that must be addressed for OCS activities are found at the BOEM website 

(USDOI, BOEM, 2011). 

8. REFERENCES CITED 

Delaware Department of Natural Resources and Environmental Control. 2004. Delaware Coastal 

Management Program. Available at: http://www.dnrec.delaware.gov/swc/SiteCollectionDocuments/

Soil/Coastal/2004%20Policy%20Document.pdf. Accessed October 5, 2011. 

Ghigiarelli, E. 2004. A guide to Maryland’s Coastal Zone Management Program Federal consistency 

process. Available at: http://www.dnr.state.md.us/bay/czm/fed_consistency_guide.pdf. Accessed 

October 5, 2011. 

North Carolina Department of Environment and Natural Resources. 2010. CAMA Permits: Federal 

consistency. Available at: http://dcm2.enr.state.nc.us/Permits/consist.htm. Accessed October 5, 

2011. 

U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, Ocean & Coastal Resource 

Management. 2008. CZMA Program change rulemaking. Available at: http://

coastalmanagement.noaa.gov/consistency/programchange.html. Accessed October 5, 2011. 

U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration. 2011. State coastal zone 

boundaries. Available at: http://coastalmanagement.noaa.gov/mystate/docs/StateCZBoundaries.pdf. 

Accessed September 26, 2011. 

U.S. Dept. of the Interior, Bureau of Ocean Energy Management. 2011. Coastal Zone Management 

Program policies for the Gulf of Mexico States applicable to Outer Continental Shelf (OCS) plan 

filings. Available at: http://www.gomr.boemre.gov/homepg/regulate/regs/ntls/enforpols.pdf. 

Accessed October 5, 2011. 
State Coastal Zone Management Programs B-7

Virginia Department of Environmental Quality. 2011. Federal consistency information package. 

Available at: http://www.deq.virginia.gov/eir/federal.html#determine. Accessed October 5, 2011. 

APPENDIX C 

EXISTING REGULATIONS,

PROTECTIVE MEASURES, AND MITIGATION

Existing Regulations, Protective Measures, and Mitigation C-iii 

TABLE OF CONTENTS 

Page 

1. INTRODUCTION ............................................................................................................................C-1

2. EXISTING REGULATIONS ...........................................................................................................C-1

2.1. G&G Permit Requirements...................................................................................................... C-1

2.2. BOEM Stipulations and Protective Measures.......................................................................... C-4

3. PROTECTIVE MEASURES INCLUDED IN THE PROPOSED ACTION ...................................C-5

3.1. Time-Area Closure for North Atlantic Right Whales.............................................................. C-5

3.2. Seismic Airgun Survey Protocol.............................................................................................. C-8

3.2.1. Rationale ................................................................................................................. C-8

3.2.2. Ramp-Up ................................................................................................................. C-9

3.2.3. Exclusion Zone.......................................................................................................... C-10

3.2.4. Visual Monitoring by Protected Species Observers.................................................. C-10

3.2.5. Shutdown Requirements ........................................................................................... C-11

3.3. HRG Survey Protocol (Renewable Energy and Marine Minerals Sites) ............................... C-11

3.3.1. Rationale ............................................................................................................... C-11

3.3.2. Protocol Requirements .............................................................................................. C-15

3.4. Guidance for Vessel Strike Avoidance .................................................................................. C-16

3.5. Guidance for Marine Debris Awareness................................................................................ C-17

3.6. Avoidance of Sensitive Seafloor Resources .......................................................................... C-17

3.6.1. Avoidance and Reporting of Historic and Prehistoric Sites...................................... C-17

3.6.2. Avoidance of Sensitive Benthic Communities.......................................................... C-18

3.7. Guidance for Activities in or Near National Marine Sanctuaries .......................................... C-18

3.8. Guidance for Military and NASA Coordination.................................................................... C-19

4. ADDITIONAL PROTECTIVE MEASURES INCLUDED IN ALTERNATIVE B .....................C-19

4.1. Expanded Time-Area Closure for North Atlantic Right Whales ........................................... C-20

4.2. Time-Area Closure for Nesting Sea Turtles Offshore Brevard County, Florida ................... C-20

4.3. Separation between Simultaneous Seismic Airgun Surveys.................................................. C-21

4.4. Seismic Airgun Survey Protocol with Required Use of Passive Acoustic Monitoring ......... C-21

5. OTHER MITIGATION AND MONITORING MEASURES CONSIDERED BUT NOT 

SELECTED.....................................................................................................................................C-24

5.1. Expanded Exclusion Zone (160 dB) ...................................................................................... C-24

5.2. Passive Acoustic Monitoring ................................................................................................. C-25

5.3. Active Acoustic Monitoring................................................................................................... C-26

5.4. Aerial Surveys........................................................................................................................ C-26

5.5. Autonomous Underwater Vehicles ........................................................................................ C-27

6. NON-AIRGUN ALTERNATIVES AND RELATED MEASURES CONSIDERED BUT 

NOT SELECTED ...........................................................................................................................C-28

6.1. Marine Vibrators (Vibroseis)................................................................................................. C-28

6.1.1. Hydraulic ............................................................................................................... C-28

6.1.2. Electric ............................................................................................................... C-29
C-iv Atlantic G&G Programmatic EIS 

6.2. Low-frequency Acoustic Source (patented) (LACS)............................................................. C-29

6.3. Deep-Towed Acoustics/Geophysics System (DTAGS)......................................................... C-30

6.4. Low Frequency Passive Seismic Methods for Exploration ................................................... C-30

6.5. Low-Impact Seismic Array (LISA) ....................................................................................... C-31

6.6. Fiber Optic Receivers............................................................................................................. C-32

6.7. Airgun Modifications to Lessen Impacts ............................................................................... C-32

6.7.1. Airgun Silencers........................................................................................................ C-32

6.7.2. Bubble Curtains......................................................................................................... C-32

6.7.3. Reduction of Sound Source Levels ........................................................................... C-33

7. REFERENCES CITED...................................................................................................................C-33

ATTACHMENT: DRAFT SEISMIC AIRGUN SURVEY PROTOCOL............................................C-39
Existing Regulations, Protective Measures, and Mitigation C-v 

LIST OF FIGURES 

Page 

Figure C-1. Area of Interest for the Proposed Action. ........................................................................... C-2

Figure C-2. Time-Area Closures Included in Alternative A. ................................................................. C-6

Figure C-3. Summary of Speed Restrictions and Locations for Vessel Operators to Comply 

with the Right Whale Strike Reduction Rule (50 CFR 224.105)........................................ C-7

Figure C-4. Time-Area Closures under Alternative B. ........................................................................ C-22

Figure C-5. Close-Up View of Time-Area Closures Offshore Brevard County under 

Alternative B..................................................................................................................... C-23

Existing Regulations, Protective Measures, and Mitigation C-vii 

LIST OF TABLES 

Page 

Table C-1 Federal Regulations Applicable to Prelease and Postlease Activities by Mineral 

Resource of Interest ............................................................................................................ C-1

Table C-2 Acoustic Characteristics of Airgun Arrays Included in the Proposed Action.................... C-9

Table C-3 Estimated Ranges (m) for Level A Harassment of Cetaceans by Airgun Arrays 

Based on the NMFS Level A Criterion............................................................................. C-10

Table C-4 Acoustic Characteristics of Representative Electromechanical Sound Sources 

Included in the Programmatic EIS .................................................................................... C-12

Table C-5 Estimated Ranges for Level A and B Harassment of Cetaceans 

byElectromechanical Sources Based on the NMFS 180-dB and 160-dB Criteria ............ C-13

Table C-6 Estimated Ranges (m) for Level B Harassment of Cetaceans by Airgun Arrays 

Based on the NMFS 160-dB Criterion.............................................................................. C-24

Existing Regulations, Protective Measures, and Mitigation C-ix 

LIST OF ACRONYMS AND ABBREVIATIONS 

1D one-dimensional 

2D two-dimensional 

3D three-dimensional 

4D four-dimensional 

AAM active acoustic monitoring 

ACNWR Archie Carr National Wildlife 

Refuge 

AN(SW)T ambient-noise (surface-wave) 

tomography 

AOI area of interest 

AUV autonomous underwater vehicle 

BOEM Bureau of Ocean Energy 

Management 

BSEE Bureau of Safety and 

Environmental Enforcement 

CFR Code of Federal Regulations 

DLI daylight imaging 

DTAGS deep-towed acoustics/geophysics 

system 

EEZ Exclusive Economic Zone 

ESA Endangered Species Act 

FAA Federal Aviation Administration 

FAZ full azimuth 

G&G geological and geophysical 

HAPC Habitat Areas of Particular 

Concern 

HRG high-resolution geophysical 

HyMAS hydrocarbon microtremor analysis 

IAGC International Association of 

Geophysical Contractors 

ITA Incidental Take Authorization 

IVI Industrial Vehicles International, 

Inc. 

LACS low level acoustic combustion 

source 

LET local earthquake tomography 

LISA low impact seismic array 

LFS low-frequency spectroscopy 

LFPS low frequency passive seismic 

MMPA Marine Mammal Protection Act 

MMS Minerals Management Service 

MPA Marine Protected Area 

NASA National Aeronautics and Space 

Administration 

NHPA National Historic Preservation Act 

NMFS National Marine Fisheries Service 

NMML National Marine Mammal 

Laboratory 

NMSA National Marine Sanctuaries Act 

NMS National Marine Sanctuary 

NOAA National Oceanic and Atmospheric 

Administration 

NTL Notice to Lessees and Operators 

OBS ocean bottom seismometer 

OCS Outer Continental Shelf 

OCSLA Outer Continental Shelf Lands Act 

PAM passive acoustic monitoring 

Programmatic EIS Programmatic 

Environmental Impact Statement 

PGS Petroleum Geo-Services 

SEL sound exposure level 

SMA Seasonal Management Area 

SWA surface-wave amplitude 

TTS temporary threshold shift 

UAS unmanned aircraft system 

U.S.C. United States Code 

USDOI U.S. Dept. of the Interior 

WAZ wide azimuth 

Existing Regulations, Protective Measures, and Mitigation C-1 

1. INTRODUCTION 

The Bureau of Ocean Energy Management (BOEM) is proposing to authorize geological and 

geophysical (G&G) activities in support of its oil and gas, renewable energy, and marine minerals 

programs in Federal waters of the Mid- and South Atlantic Outer Continental Shelf (OCS) and adjacent 

State waters. The area of interest (AOI) for the proposed action includes the Mid- and South Atlantic 

OCS Planning Areas, as well as adjacent State waters (outside of estuaries) and waters beyond the 

Exclusive Economic Zone (EEZ) extending to 648 km (350 nmi) from shore (Figure C-1). 

All G&G activities authorized by BOEM must comply with existing laws and regulations as 

described in Chapter 1.0 of the Programmatic Environmental Impact Statement (Programmatic EIS). 

These include measures to avoid or reduce potential impacts of G&G activities. Compliance with 

existing laws and regulations – by BOEM as well as individual operators, when required – may result in 

additional measures or changes to the measures described here. In addition, a suite of protective measures 

is included in the proposed action as described in Chapter 2.0 of the Programmatic EIS. This appendix 

describes and discusses the rationale for the measures selected for this program. It also describes 

measures that were considered but not selected, including measures and technologies identified for 

possible future use when proven effective and feasible. Additional mitigation measures may be 

incorporated into the proposed action through the public review process for the Programmatic EIS. 

2. EXISTING REGULATIONS 

This section identifies mitigation or protective measures already in place as a result of current G&G 

permit requirements, including G&G operator compliance with lease stipulations and other protective 

measures, as well as applicable guidance documents. Permit requirements and existing mitigation or 

protective measures are included in the proposed action. 

2.1. G&G PERMIT REQUIREMENTS

Pursuant to 30 Code of Federal Regulations (CFR) 551.4, a permit must be obtained to conduct 

prelease geological or geophysical exploration for oil, gas, and sulphur resources. Permits for exploration 

for other minerals in support of competitive leasing are granted pursuant to requirements outlined in 

30 CFR 580.3. Permit applications must be submitted to BOEM in accordance with the requirements 

outlined in 30 CFR 551.5 and 30 CFR 551.6 and explained further in applicable Letters to Permittees. 

The Letter to Permittees dated 20 January 1989 specifies forms and maps, stipulations, and special 

provisions applicable to most permit activity. The 30 CFR 551 regulations do not apply to G&G 

activities conducted by, or on behalf of, a lessee on a leased block. Such G&G activities are governed by 

30 CFR 550.201 regulations and by applicable Notices to Lessees and Operators. Table C-1 identifies 

the appropriate Federal regulations and their applicability to select mineral resources and activity phase. 

Table C-1 

 

Federal Regulations Applicable to Prelease and Postlease Activities 

by Mineral Resource of Interest 

Regulatory Citation Mineral Resource Activity Phase 

30 CFR 550 Oil, gas, and sulphur Postlease (i.e., on-lease) 

30 CFR 551 Oil, gas, and sulphur Prelease or off-lease exploration or 

scientific research 

30 CFR 580a All minerals exclusive of oil, gas, and sulphur Prelease (prospecting) 

30 CFR 585 Renewable energy Prelease and postlease a

 30 CFR 580 regulations apply only to G&G activities in support of competitive leasing. For noncompetitive leasing for public 

works, authorizations are issued pursuant to Section 11 of the OCSLA. 
C-2 Atlantic G&G Programmatic EIS 

Figure C-1. Area of Interest for the Proposed Action. 
Existing Regulations, Protective Measures, and Mitigation C-3 

Geological and geophysical explorations for mineral resources may not be conducted in the OCS 

without an approved permit unless such activities are being conducted pursuant to a lease issued or 

maintained under the Outer Continental Shelf Lands Act (OCSLA). Separate permits must be obtained 

for either geological or geophysical explorations for mineral resources. 

The OCSLA directs BOEM to ensure G&G data are obtained in a technically safe and 

environmentally sound manner. Regulations at 30 CFR 551.6 state that permit holders for G&G activities 

must not 

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

right-of-use, notice, or permit issued or maintained under the Act; 

 cause harm or damage to life (including fishes and other aquatic life), property, or to 

the marine, coastal, or human environment; 

 cause harm or damage to any mineral resource (in areas leased or not leased); 

 cause pollution; 

 disturb archaeological resources; 

 create hazardous or unsafe conditions; or 

 unreasonably interfere with or cause harm to other uses of the area. 

Geological and Geophysical operators conducting activities under 30 CFR 551 must immediately 

report to the Director, BOEM, when 

 hydrocarbon occurrences are detected; 

 environmental hazards are encountered that constitute an imminent threat to human 

life or property; or 

 activities occur that adversely affect the environment, aquatic life, archaeological 

resources, or other uses of the area in which the exploration or scientific research 

activities are conducted. 

The Energy Policy Act of 2005 (Public Law 109-58) added Section 8(p)(1)(C) to the OCSLA, which 

mandated that the Secretary of the Interior issue leases, easements, or rights-of-way on the OCS for the 

purpose of renewable energy development. The Secretary delegated this authority to the former Minerals 

Management Service (MMS), now BOEM. In addition to providing the authority to issue leases, 

easements, and rights-of-way, the Energy Policy Act included a requirement that any activity permitted 

under this authority be carried out in a manner that provides for various factors including 

 safety; 

 protection of the environment; 

 prevention of waste; 

 conservation of the natural resources of the OCS; 

 prevention of interference with reasonable uses of the exclusive economic zone, the 

high seas, and the territorial seas; 

 consideration of any other use of the sea or seabed, including use for a fishery, a sea 

lane, a potential site of a deepwater port, or navigation; 

 public notice and comment on any proposal submitted for a lease, easement, or 

right-of-way under this subsection; and 

 oversight, inspection, research, monitoring, and enforcement relating to a lease, 

easement, or right-of-way under this subsection.” 

On April 22, 2009, BOEM promulgated final regulations implementing this authority at 30 CFR 585 

(Federal Register, 2009). Under the renewable energy regulations, after a lease is issued, the lessee may 

not commence construction of meteorological or other site assessment facilities until a Site Assessment 

Plan and the site characterization survey reports are submitted to and reviewed by BOEM 

(30 CFR 585.605 – 585.618). The lessee’s Site Assessment Plan must contain a description of 

environmental protection features or measures that the lessee will use. Similarly, when a grant is made 
C-4 Atlantic G&G Programmatic EIS 

for a right of way, or right of use and easement, the grantee may not commence construction or perform 

other site assessment activities until a General Activities Plan and site characterization survey reports are 

submitted to and reviewed by BOEM (30 CFR 285.645-648). 

The BOEM has developed guidelines for providing G&G, hazards, and archaeological information 

pursuant to 30 CFR 585 (U.S. Dept. of the Interior [USDOI], BOEM, 2011). The guidelines specify that 

BOEM recommends avoidance as a primary mitigation strategy. Avoidance strategies seek to ensure that 

harm or damage to objects of historical or archaeological significance will be less likely. The applicant 

has the option to demonstrate through additional investigations that an archaeological resource either does 

not exist or would not be adversely affected by the seafloor/bottom-disturbing activities. If an applicant, 

while conducting activities, discovers a potential archaeological resource such as the presence of a 

shipwreck (e.g., a sonar image or visual confirmation of an iron, steel, or wooden hull, wooden timbers, 

anchors, concentrations of historic objects, piles of ballast rock), prehistoric artifacts, and/or relict 

landforms, etc. within the project area, the applicant is to: 

 immediately halt seafloor/bottom-disturbing activities within the area of discovery; 

 notify the appropriate BOEM/Office of Offshore Alternative Energy Programs 

Environmental Branch Chief within 72 hr of its discovery; and 

 keep the location of the discovery confidential and take no action that may adversely 

affect the archaeological resource until BOEM has made an evaluation and instructs 

the applicant on how to proceed. 

The BOEM may require the applicant to conduct additional investigations to determine if the resource 

is eligible for listing in the National Register of Historic Places. 

2.2. BOEM STIPULATIONS AND PROTECTIVE MEASURES

The BOEM currently requires oil and gas operators to comply with a series of stipulations and 

protective measures during G&G activities. These requirements effectively represent mitigation measures 

designed to reduce or eliminate impacts to sensitive resources. Such measures are implemented through 

regulations governing prelease and postlease G&G activities. Key points consist of the following: 

 Explosives Prohibition: Explosives cannot be used for G&G activities except under 

written authorization from the Regional Supervisor. Further protective measures 

(including Endangered Species Act [ESA] Section 7 consultation with the National 

Marine Fisheries Service [NMFS]) and a Marine Mammal Protection Act [MMPA] 

authorization apply in the event that explosives are proposed for use. 

 Archaeological Resources: The permittee must report discovery of any 

archaeological resource (i.e., shipwreck/prehistoric site) to BOEM and take 

precautions to protect the resource from operational activities. 

 Seismic Safety: All pipes, buoys, and other markers used in connection with seismic 

work must be properly flagged and lighted according to the navigation rules of the 

U.S. Army Corps of Engineers and the U.S. Coast Guard. 

There are no active oil and gas leases in the Atlantic OCS. In the event that leasing occurs during the 

period of the proposed action, BOEM may add measures to mitigate the impacts of lease-specific 

activities in the form of lease stipulations. In addition, BOEM provides additional guidance to lessees 

and operators through Notices to Lessees and Operators (NTLs). 

At a programmatic level, there are no mitigation measures that apply to G&G activities conducted in 

support of renewable energy development; however, best management practices were documented in the 

Programmatic EIS for the renewable energy program (USDOI, MMS, 2007, pp. 2-20). A NEPA 

evaluation is part of the approval process for OCS plans, without exception, under the renewable energy 

program. A proposed action at a specific location, tool type, and intensity of G&G activity are subjected 

to evaluation, which may be an Environmental Assessment or an EIS. The consultations required under 

environmental law for protected species are part of the NEPA evaluation. Through the NEPA process, 

BOEM may identify mitigation measures to avoid/minimize environmental impacts during G&G surveys. 
Existing Regulations, Protective Measures, and Mitigation C-5 

Mitigation measures may be implemented as a condition for OCS plan approval. Additional mitigation 

measures may be required as a result of consultations under the ESA or MMPA. 

Similarly, at a programmatic level, there are no mitigation measures that apply to G&G activities 

under the marine minerals program. Under Section 11 of the OCSLA, BOEM may authorize G&G 

prospecting for non-energy marine minerals, except in the case that another Federal agency is performing 

the survey on the OCS. Before authorizing any proposed prospecting, BOEM undertakes the necessary 

environmental review, including preparation of a NEPA document and consultations for protected 

species. Through the NEPA process, BOEM may identify mitigation measures to avoid/minimize 

environmental impacts during G&G surveys. Mitigation measures may be implemented as a condition 

for survey authorization. 

3. PROTECTIVE MEASURES INCLUDED IN THE PROPOSED ACTION 

The following protective measures are included in the proposed action: 

 a time-area closure for North Atlantic right whales; 

 a seismic airgun survey protocol; 

 a high-resolution geophysical (HRG) survey protocol (for renewable energy and 

marine minerals sites); 

 guidance for vessel strike avoidance; 

 guidance for marine debris awareness; 

 avoidance and reporting of historic and prehistoric sites; 

 avoidance of sensitive benthic communities; 

 guidance for activities in or near National Marine Sanctuaries; and 

 guidance for military and NASA coordination. 

3.1. TIME-AREA CLOSURE FOR NORTH ATLANTIC RIGHT WHALES

Alternative A includes a time-area closure intended to avoid most impacts from vessel strikes or 

ensonification of the water column on North Atlantic right whales. It is estimated that this closure would 

avoid about two-thirds of the incidental takes of North Atlantic right whales by active acoustic sound 

sources over the period of the Programmatic EIS. Although right whales could occur anywhere within 

the AOI, they are most likely to be found in the calving/nursery areas offshore the southeastern U.S. coast 

during the winter months and near the South Atlantic and Mid-Atlantic coast during their seasonal 

migrations (Knowlton et al., 2002). 

The locations and timing of the closure are shown in Figure C-2. The total closure area under 

Alternative A would be 7,589,594 ac (30,714 km2

) or approximately 4 percent of the AOI. No G&G 

surveys using airguns would be authorized within the designated right whale critical habitat area from 

November 15 through April 15 nor within the Mid-Atlantic and Southeast U.S. Seasonal Management 

Areas (SMAs) during the times when vessel speed restrictions are in effect under the Right Whale Ship 

Strike Reduction Rule (50 CFR 224.105). However, HRG surveys proposed in critical habitat area and 

SMAs may be considered on a case-by-case basis only if: (1) they are proposed for renewable energy or 

marine minerals operations; and (2) they use acoustic sources other than air guns. The coincidence is 

necessary because of other biological use windows or project monitoring requirements. Any such 

authorization may include additional mitigation and monitoring requirements to avoid or significantly 

reduce impacts on right whales. Other supporting surveys (e.g., biological surveys) would not be affected 

by this restriction. 

The Southeast U.S. SMA, with seasonal restrictions in effect from November 15 to April 15, is a 

continuous area that extends from St. Augustine, Florida, to Brunswick, Georgia, extending 37 km 

(20 nmi) from shore (Figure C-3). The Mid-Atlantic U.S. SMA, with seasonal restrictions from 

November 1 through April 30, is a combination of both continuous areas and half circles drawn with 

37-km (20-nmi) radii around the entrances to certain bays and ports. Within the AOI, the Mid-Atlantic 

U.S. SMA includes a continuous zone extending between Wilmington, North Carolina, and Brunswick, 

Georgia, as well as the entrance to Delaware Bay (Ports of Wilmington [Delaware] and Philadelphia), the 
C-6 Atlantic G&G Programmatic EIS 

Figure C-2. Time-Area Closures Included in Alternative A. 
Existing Regulations, Protective Measures, and Mitigation C-7 

Figure C-3. Summary of Speed Restrictions and Locations for Vessel Operators to Comply with the Right 

Whale Strike Reduction Rule (50 CFR 224.105) (Source: USDOC, NOAA, 2011). 
C-8 Atlantic G&G Programmatic EIS 

entrance to Chesapeake Bay (Ports of Hampton Roads and Baltimore), and the Ports of Morehead City 

and Beaufort, North Carolina (Figure C-3). 

Exceptions to the right whale time-area closure could occur if a survey was needed to serve important 

operational or monitoring requirements for a particular project. For example, monitoring surveys for 

renewable energy (e.g., scour, cable burial) might need to take place at fixed intervals to capture seasonal 

changes or safety-related conditions. Another example would be a marine minerals project in which 

dredging is not seasonally restricted and real-time bathymetry data must be collected to track dredging 

operations or pre- and post-bathymetric surveys must be collected immediately before or after dredging to 

establish volumes borrowed. 

3.2. SEISMIC AIRGUN SURVEY PROTOCOL

All authorizations for seismic airgun surveys (those involving airguns as an acoustic source) would 

include a survey protocol that specifies mitigation measures for protected species, including an exclusion 

zone, ramp-up requirements, visual monitoring by protected species observers prior to and during seismic 

airgun surveys, and array shutdown requirements. The protocol specifies the conditions under which 

airgun arrays can be started and those under which they must be shut down. It also includes the 

recommended but optional use of passive acoustic monitoring (PAM) to help detect vocalizing marine 

mammals. The protocol requirements apply specifically to airguns, not electromechanical sources such as 

side-scan sonars, boomer and chirp subbottom profilers, and single beam or multibeam depth sounders 

that may be operating concurrently during seismic airgun surveys. 

A draft seismic airgun survey protocol is provided as the Attachment to this appendix. The draft 

protocol is based on Joint BOEM-BSEE NTL 2012-G02 (“Implementation of Seismic Survey Mitigation 

Measures and Protected Species Observer Program”) (USDOI, BOEM and BSEE, 2012a), with key 

exceptions as noted in the protocol. 

3.2.1. Rationale 

The purpose of the operational measures included in the seismic airgun survey protocol is to prevent 

injury to marine mammals and sea turtles and to avoid most Level A harassment of marine mammals. 

There are 38 species of marine mammals potentially occurring in the Area of Interest (AOI), as 

described in Chapter 4.2.2 of the Programmatic EIS. They include 34 species of cetaceans, 3 species of 

pinnipeds, and one sirenian (the Florida manatee). The pinnipeds (harbor seal, gray seal, and hooded 

seal) are considered to be extralimital in the AOI and are unlikely to be exposed to underwater sound 

from seismic airgun surveys under the proposed action. Manatees are present only in inland and 

near-coastal waters along the southeast coast and are unlikely to be exposed to underwater sound from 

seismic airgun surveys under the proposed action. Incidental take calculations in Appendix E based on 

abundance data for the AOI predict zero incidental takes of pinnipeds or manatees, even without 

considering operational mitigation measures included in the seismic airgun survey protocol. 

For the analysis in the Programmatic EIS, two sizes of airgun arrays were modeled, based on current 

usage in the Gulf of Mexico, and considered representative for potential Atlantic G&G seismic surveys: 

 large airgun array (5,400 in3

) – this array was used to represent sound sources for 

deep penetration seismic surveys, including 2D, 3D, WAZ, and other variations; and 

 small airgun array (90 in3

) – this array was used to represent sound sources for HRG 

surveys for oil and gas exploration sites. 

Detailed acoustic characteristics of airguns are discussed in Appendix D. Broadband source levels 

are 230.7 dB re 1 μPa for the large airgun array and 210.3 dB re 1 μPa for the small array (Table C-2). 

Although airguns have a frequency range from about 10 to 2,000 Hz, most of the acoustic energy is 

radiated at frequencies below 200 Hz. 
Existing Regulations, Protective Measures, and Mitigation C-9 

Table C-2 

 

Acoustic Characteristics of Airgun Arrays Included in the Proposed Action 

Source Usage Operating Frequencies 

Broadband 

Source Level 

(dB re 1 Pa at 1 m) 

Large Airgun Array 

(5,400 in2

) 

Deep penetration seismic 

surveys, oil and gas exploration 

(2D, 3D, WAZ, VSP, 4D, etc.) 

10-2,000 Hz 

(most energy at <200 Hz) 230.7 

Small Airgun Array 

(90 in2

) 

HRG surveys, 

oil and gas exploration 

10-2,000 Hz 

(most energy at <200 Hz) 210.3 

Abbreviations: 2D = two-dimensional; 3D = three-dimensional; 4D = four-dimensional; HRG = high-resolution geophysical; 

VSP = vertical seismic profile; WAZ = wide azimuth. 

Source: Appendix D. 

Acoustic pulses from airguns are within the hearing range of all marine mammals in the AOI 

(Appendix H). All of the mysticetes occurring in the AOI are low-frequency cetaceans (7 Hz-22 kHz), 

and most of the odontocetes are mid-frequency cetaceans (150 Hz-160 kHz), with the exception of the 

harbor porpoise (a high-frequency cetacean, 200 Hz-180 kHz). Manatees have hearing capabilities that 

are generally similar to phocid pinnipeds, with functional hearing between about 250 Hz and ~90 kHz. 

Airgun pulses are also within the hearing range of sea turtles, whose best hearing is mainly below 

1,000 Hz (Appendix I). 

To reduce the risk of injury and Level A harassment, the seismic airgun survey protocol would 

establish an exclusion zone based on the predicted range at which animals could be exposed to a received 

sound pressure level of 180 dB re 1 μPa, which is the current NMFS criterion for Level A harassment of 

cetaceans. The radius of the exclusion zone would be calculated on a survey-specific basis, but would not 

be less than 500 m (1,640 ft). This exclusion zone applies specifically to airguns, not electromechanical 

sources such as side-scan sonars, boomer and chirp subbottom profilers, and single beam or multibeam 

depth sounders that may be operating concurrently during seismic airgun surveys. Although there are no 

NMFS noise exposure criteria for sea turtles, the mitigation measures are expected to similarly reduce the 

risk of temporary or permanent hearing loss in sea turtles. The operational mitigation measures would 

reduce the extent of, but not prevent, behavioral responses including Level B harassment of marine 

mammals. Other measures such as the time-area closure for North Atlantic right whales (Chapter 3.1) 

would help to reduce the risk of those impacts. Key elements of the protocol are discussed in the 

following sections. 

3.2.2. Ramp-Up 

Ramp-up (also known as “soft start”) entails the gradual increase in intensity of an airgun array over a 

period of 20 min or more, until maximum source levels are reached. The intent of ramp-up is to either 

avoid or reduce the potential for instantaneous hearing damage to an animal (from the sudden initiation of 

an acoustic source at full power) that might be located in close proximity to an airgun array. Increasing 

sound levels are designed to warn animals of pending seismic operations, and to allow sufficient time for 

those animals to leave the immediate area. Increasing sound levels (e.g., from an airgun array) are 

thought to be annoying or aversive to marine mammals. Under optimal conditions, sensitive individuals 

are expected to move out of the area, beyond the range where hearing damage might occur. 

Ramp-up has become a standard mitigation measure in the U.S. and worldwide. The International 

Association of Geophysical Contractors (IAGC) recommends ramp-up in its seismic survey guidelines 

(IAGC, 2011). In the Gulf of Mexico, BOEM requires ramp-up for operators working in water depths 

>200 m throughout the Gulf and all OCS waters of the Eastern Gulf of Mexico Planning Area under Joint 

BOEM-BSEE NTL 2012-G02 (USDOI, BOEM and BSEE, 2012a). 

Although ramp-up is widely used, it is used mainly as a “common sense” procedure, and there is little 

information on its effectiveness (Weir and Dolman, 2007; Parsons et al., 2009). 
C-10 Atlantic G&G Programmatic EIS 

3.2.3. Exclusion Zone 

The seismic airgun survey protocol includes an exclusion zone to prevent injury to marine mammals 

and sea turtles and to avoid Level A harassment of marine mammals to the maximum extent practicable. 

The radius of the exclusion zone would be based on the predicted range at which animals could be 

exposed to a received sound pressure level of 180 dB re 1 μPa, which is the current NMFS criterion for 

Level A harassment of cetaceans. The radius of the exclusion zone would be calculated on a 

survey-specific basis, but would not be less than 500 m (1,640 ft). This exclusion zone applies 

specifically to airguns, not electromechanical sources such as side-scan sonars, boomer and chirp 

subbottom profilers, and single beam or multibeam depth sounders that may be operating concurrently 

during seismic airgun surveys. 

Although the NMFS also uses a criterion of 190 dB re 1 μPa for Level A harassment of pinnipeds, 

based on the rare occurrence of pinnipeds in the AOI it is unlikely that a smaller exclusion zone based on 

the 190-dB criterion would be appropriate for any seismic airgun survey there. There are no noise 

exposure criteria for sea turtles, but a 180-dB exclusion zone is expected to prevent mortalities, injuries, 

and most auditory impacts on sea turtles as well. 

Based on calculations in Appendix D and summarized in Table C-3, the 180-dB zone for a large 

airgun array (5,400 in3

) ranges from 799 to 2,109 m (2,622 to 6,920 ft), with a mean of 1,086 m 

(3,563 ft). Marine mammals can be detected at distances of up to several kilometers, depending on sea 

state and the animal’s size and behavior. Sea turtles are not likely to be detected beyond 500 m (1,640 ft). 

For oil and gas HRG surveys using a small airgun array (90 in3

), the 180-dB zone ranges from 76 to 

186 m (249 to 610 ft), with a mean of 128 m (420 ft) (Table C-3). A 500-m (1,640-ft) radius exclusion 

zone can be effectively monitored and would encompass the zone where Level A harassment could occur. 

Table C-3 

 

Estimated Ranges (m) for Level A Harassment of Cetaceans by Airgun Arrays 

Based on the NMFS Level A Criterion 

NMFS Level A Criterion

Equipment Usage 180 dB re 1 μPa (rms) 

Number 

of Scenarios 

Modeled 

Statistics 

Rmax R95%

Min (m) 799 737 

5,400 in Max (m) 2,109 1,677 3 Airgun Array 

Deep penetration seismic 

surveys, oil and gas 

exploration (2D, 3D, WAZ, 

VSP, 4D, etc.) 

21 

Mean (m) 1,086 930 

Min (m) 76 74 

90 in Max (m) 186 177 3 Airgun Array HRG surveys, oil and gas 

exploration 21 

Mean (m) 128 124 

Rmax is the maximum received sound pressure level. R95% is the received level over 95% of the energy of the pulse. 

Source: Appendix D.

3.2.4. Visual Monitoring by Protected Species Observers 

The seismic airgun survey protocol includes visual monitoring of the exclusion zone by trained 

protected species observers. At least two protected species observers will be required on watch aboard 

seismic vessels at all times during daylight hours (dawn to dusk – i.e., from about 30 min before sunrise 

to 30 min after sunset) when seismic operations are being conducted, unless conditions (fog, rain, 

darkness) make sea surface observations impossible. If conditions deteriorate during daylight hours such 

that the sea surface observations are halted, visual observations must resume as soon as conditions permit. 

Ongoing activities may continue but may not be initiated under such conditions (i.e., without appropriate 

pre-activity monitoring). Operators may engage trained third party observers, utilize crew members after 

training as observers, or use a combination of both third party and crew observers. 

The main tasks of protected species observers are to monitor the exclusion zone for protected species 

and to observe and document their presence and behavior. Observers search the area around the vessel 
Existing Regulations, Protective Measures, and Mitigation C-11 

using high-powered, pedestal-mounted, “Big Eye” binoculars, hand-held binoculars, and the unaided eye. 

For larger monitoring programs with a specified visual observation platform, two observers survey for 

protected species generally using the high-powered binoculars, while a third observer searches with the 

unaided eye and occasionally hand-held binoculars, and serves as data recorder. If the vessel is utilizing a 

passive acoustic monitoring (PAM) system, a fourth observer will be assigned to monitor that station and 

communicate with the third observer on the visual observing platform. Data are recorded on paper sheets 

and/or a laptop computer that has direct input from the vessel’s global positioning system navigation 

system. Observers rotate among the duty stations at regular intervals, and alternate work and rest periods 

based upon a pre-determined schedule. In the event a marine mammal is sighted or otherwise detected 

within the impact zone, seismic operations are suspended until the animal leaves the area (see 

Attachment). 

Visual, shipboard monitoring is affected by limitations on sightability of individuals due to poor 

visibility (fog, elevated Beaufort sea state, nighttime operations), species detectability (cryptic species), 

and/or observer fatigue. Routine activities of marine mammals (e.g., diving duration patterns, pod size, 

overt behaviors) show considerable variability between species, thereby affecting whether or not animals 

are sighted (i.e., availability bias). During nighttime operations or during periods of reduced visibility, 

several options are available to allow for continual monitoring of the impact zone (e.g., shipboard lighting 

of waters around the vessel, use of enhanced vision equipment, night-vision equipment, and acoustic 

monitoring [both active and passive]). However, the efficiency of visual monitoring during nighttime 

hours, using shipboard lighting or enhanced vision equipment, is limited when compared with visual 

monitoring during daylight hours. 

3.2.5. Shutdown Requirements 

The seismic airgun survey protocol requires shutdown of the airgun array any time a marine mammal 

or sea turtle is observed within the exclusion zone, whether due to the animal’s movement, the vessel’s 

movement, or because the animal surfaced inside the exclusion zone. In the event of a shutdown, seismic 

operations and ramp-up of airguns would recommence only when the sighted animal has cleared the 

exclusion zone and no other marine mammals or sea turtles have been sighted within the exclusion zone 

for at least 30 min. However, shutdown would not be required for dolphins approaching the vessel or 

towed equipment at a speed and vector that indicates voluntary approach to bow-ride or chase towed 

equipment. If a dolphin voluntarily moves into the exclusion zone after the airguns are operating, it is 

reasoned that the sound pressure level is not negatively affecting that particular animal. 

3.3. HRG SURVEY PROTOCOL (RENEWABLE ENERGY AND MARINE MINERALS 

SITES) 

The HRG surveys of renewable energy and marine minerals sites would use only electromechanical 

sources such as side-scan sonar, boomer and chirp subbottom profilers, and single beam and multibeam 

depth sounders. The BOEM does not expect that airguns would be used for these surveys. All 

authorizations for non-airgun HRG surveys would include requirements for visual monitoring of an 

exclusion zone by protected species observers and startup and shutdown requirements. 

The HRG surveys for oil and gas exploration and development sites typically use the 

electromechanical acoustic sources operating concurrently with airgun arrays. These surveys would be 

subject to the seismic airgun survey protocol described in Chapter 3.2. 

3.3.1. Rationale 

Important considerations in defining an exclusion zone (or “safe” range) include the source level, 

operating frequencies, pulse duration, and directivity of the source as well as the hearing capabilities of 

the receiving animals. Acoustic characteristics of electromechanical sources are discussed in detail in 

Appendix D and summarized in Table C-4. 
C-12 Atlantic G&G Programmatic EIS 

Table C-4 

 

Acoustic Characteristics of Representative Electromechanical Sound Sources Included in the Programmatic EIS 

Within Hearing Range Source Broadband Source Level 

(dB re 1 Pa at 1 m) 

Operating 

Frequencies Cetaceans Sea Turtles 

Boomer 212 200 Hz–16 kHz Yes Yes 

100 kHz Yes No Side-Scan Sonar 226 400 kHz No No 

3.5 kHz Yes No 

Chirp Subbottom Profiler 222 12 kHz Yes No 

200 kHz No No 

Multibeam Depth Soundera 213 240 kHz No No a

 Single beam depth sounders may also be used for seafloor mapping, and the frequencies and source levels may differ. The 

multibeam depth sounder was selected as a representative source and is conservative from the standpoint of acoustic impacts. 

_____ = no auditory impacts expected because frequency is beyond hearing range. 

Source: Appendix D. 

Based on a review of marine mammal hearing, Appendix H recognizes three cetacean groups: 

low-frequency cetaceans (7 Hz to 22 kHz), mid-frequency cetaceans (150 Hz to 160 kHz) and 

high-frequency cetaceans (200 Hz to 180 kHz). Boomer pulses are within the hearing range of all three 

cetacean groups. However, the operating frequency of the representative multibeam system (240 kHz) is 

above the hearing range of all three groups. For side-scan sonar, the 100 kHz operating frequency is 

within the hearing range of mid- and high-frequency cetaceans, but the 400 kHz frequency is above the 

range of all groups. For the chirp subbottom profiler, the 3.5 kHz and 12 kHz frequencies are within the 

hearing range of all three cetacean groups, but the 200 kHz is above the range of all groups. Frequencies 

emitted by individual equipment may differ from these representative systems selected for programmatic 

analysis. 

Sea turtles are low-frequency specialists whose best hearing is mainly below 1,000 Hz (Appendix I). 

Acoustic signals from electromechanical sources other than the boomer are not likely to be detectable by 

sea turtles. Because of the relatively low source level of the boomer as discussed below, sea turtles are 

unlikely to hear boomer pulses unless they are very near the source. 

3.3.1.1. Injury Ranges Calculated Using the 180-dB NMFS Criterion 

To reduce the risk of injury and Level A harassment of marine mammals, the HRG survey protocol 

would establish an exclusion zone based on the predicted range at which animals could be exposed to a 

received sound pressure level of 180 dB re 1 μPa, which is the current NMFS criterion for Level A 

harassment of cetaceans. The operational mitigation measures would not prevent all Level A harassment 

and would reduce the extent of, but not prevent, behavioral responses including Level B harassment. 

Table C-5 lists the maximum 180-dB range calculated for electromechanical sources, based on 

acoustic modeling in Appendix D. The range of values reflects the various geographic and seasonal 

scenarios modeled. The 180-dB radius ranged from 38 to 45 m (125 to 148 ft) for the boomer and from 

32 to 42 m (105 to 138 ft) for the chirp subbottom profiler. The 180-dB radius was 27 m (89 ft) for the 

multibeam depth sounder under all scenarios. The side-scan sonar had the largest 180-dB radius, ranging 

from 128 to 192 m (420 to 630 ft). 

The initial 180-dB calculations in Table C-5 are based on nominal source levels and do not take into 

account the pulse duration. As indicated in the table, the pulses produced by all of the electromechanical 

sources are much shorter than 1 s. As summarized by Au and Hastings (2008), when receiving tone 

pulses, the mammalian ear behaves like an integrator with an “integration time constant.” Energy is 

summed over the duration of a pulse until the pulse is longer than the integration time constant. Studies 

of bottlenose dolphins by Johnson (1968) indicate an integration time constant of approximately 100 ms. 

A 10-ms pulse with a received SPL of 180 dB would be integrated over a 100-ms period, resulting in a 

10-fold (10 dB) reduction. Using the assumption of a 100-ms integration time, the 180-dB radii for 

side-scan sonar and multibeam depth sounder were recalculated to account for short pulse duration as 

shown in Table C-5. For the boomer and multibeam depth sounder, the recalculated 180-dB radius was 
Existing Regulations, Protective Measures, and Mitigation C-13 

<5 m under all scenarios. The recalculated 180-dB radius ranged from 65 to 96 m (213 to 315 ft) for the 

side-scan sonar and from 26 to 35 m (85 to 115 ft) for chirp subbottom profiler. Specific considerations 

for each source are discussed below. 

Table C-5 

 

Estimated Ranges for Level A and B Harassment of Cetaceans 

byElectromechanical Sources Based on the NMFS 180-dB and 160-dB Criteria 

180-dB Radius (m) 160-dB Radius (m) 

Equipment 

Number of 

Scenarios 

Modeled 

Pulse 

Duration 

Adjustment 

(dB) for Short 

Pulse 

Durationa

Calculated 

using Nominal 

Source Levelb

Recalculated 

for Short Pulse 

Durationa

Calculated 

using Nominal 

Source Levelb

Recalculated 

for Short Pulse 

Durationa

Boomer 14 180 μs -27.3 38-45 <5 1,054-2,138 16 

Side-Scan Sonar 14 20 ms -7.0 128-192 65-96 500-655 337-450 

Chirp Subbottom 

Profiler 14 64 ms -1.9 32-42 26-35 359-971 240-689 

Multibeam Depth 

Sounder 7 225 μs -26.5 27 <5 147-156 12 

a

 The nominal source level was adjusted by the amount indicated to recalculate the 180-dB radius in the last column. b

 The value is the radius (Rmax) for the maximum received sound pressure level (Appendix D). 

Source: Appendix D. 

3.3.1.1.1. Boomer 

The frequency range of the representative boomer (200 Hz to 16 kHz) is entirely within the hearing 

range of all cetacean groups and is also within the expected hearing range of sea turtles. Based on a 

source level of 212 dB re 1 μPa, the 180-dB radius is estimated to range from 38 to 45 m (125 to 148 ft) 

for the various geographic and seasonal scenarios modeled. However, taking into account the short pulse 

duration (180 μs), the recalculated 180-dB radius is <5 m (16 ft) in all modeled scenarios (Table C-5). 

3.3.1.1.2. Side-Scan Sonar 

For the representative side-scan sonar, the 100 kHz operating frequency is within the hearing range of 

mid- and high-frequency cetaceans, but the 400 kHz frequency is above the range of all groups. Sea 

turtles are not expected to hear this source. Based on a source level of 226 dB re 1 μPa, the 180-dB 

radius is estimated to range from 128 to 192 m (420 to 630 ft) for the various geographic and seasonal 

scenarios modeled. Taking into account the short pulse length of 20 ms, the recalculated 180-dB radius 

ranges from 65 to 96 m (213 to 315 ft) (Table C-5). 

3.3.1.1.3. Chirp Subbottom Profiler 

The representative chirp subbottom profiler operates at three frequencies: 3.5 kHz, 12 kHz, and 

200 kHz. The highest frequency (200 kHz) is above the hearing range for all cetaceans. Sea turtles are 

not expected to hear this source. Based on a source level of 222 dB re 1 μPa, the 180-dB radius ranges 

from 32 to 42 m (105 to 138 ft) for the various geographic and seasonal scenarios modeled. Because the 

pulse length of 64 ms is relatively close to the 100 ms integration time assumed for the cetacean ear, the 

correction for pulse length reduces the ranges only slightly to 26-35 m (85-115 ft) (Table C-5). 

3.3.1.1.4. Multibeam Depth Sounder 

Based on a source level of 213 dB re 1 μPa, the 180-dB radius calculated for the multibeam depth 

sounder is 27 m (89 ft) for all of the geographic and seasonal scenarios modeled. Taking into account the 

short pulse duration (225 μs), the radius is further reduced to <5 m (16 ft) for all modeled scenarios. 

More importantly, because the operating frequency of the representative multibeam system (240 kHz) is 

above the hearing range of all three cetacean groups, no auditory impacts are expected. Similarly, sea 

turtles are not expected to hear this source. 
C-14 Atlantic G&G Programmatic EIS 

The relatively low risk of auditory impacts on marine mammals from multibeam depth sounders is 

consistent with a recent analysis by Lurton and DeRuiter (2011) taking into account both the short pulse 

duration and high directivity of these sources. 

3.3.1.2. Injury Ranges Calculated Using the Southall Criteria 

Based on data for onset of temporary threshold shift (TTS), Southall et al. (2007) proposed dual 

injury criteria for cetaceans exposed to non-pulse sources. In the Southall et al. (2007) terminology, all of 

the electromechanical sources evaluated here would be considered non-pulse sources. The first injury 

criterion is a sound exposure level (SEL) of 215 dB re 1 μPa2

 s and the second is a flat-weighted peak 

pressure exceeding 230 dB re 1 μPa. Injury is assumed to occur if either criterion is exceeded (or both). 

For all of the representative electromechanical sources in this Programmatic EIS, the source level is 

less than 230 dB re 1 μPa and therefore the pressure criterion would not be exceeded and the injury radius 

is zero. Calculation of the injury radius using the SEL criterion is complicated because exposure depends 

on the ping rate and the number of pulses an animal receives; however, in general, predicted injury radii 

are expected to be less than 10 m (33 ft) for all of the sources. 

3.3.1.3. Level B Harassment Ranges Calculated Using the 160-dB NMFS Criterion 

Table C-5 also lists the maximum 160-dB range calculated for electromechanical sources, based on 

acoustic modeling in Appendix D. The range of values reflects the various geographic and seasonal 

scenarios modeled. The boomer had the largest 160-dB radius, ranging from 1,054 to 2,138 m (3,458 to 

7,015 ft), followed by the chirp subbottom profiler (359-971 m or 1,178-3,186 ft), the side-scan sonar 

(500-655 m or 1,640-2,149 ft) and the multibeam depth sounder (147-156 m or 482-512 ft). 

Values taking into account pulse duration are shown in the last column of Table C-5. Due to the very 

short pulse duration, the boomer and multibeam depth sounder have radii of 16 m (52 ft) and 12 m (39 ft), 

respectively. The recalculated 160-dB radius ranged from 240 to 689 m (787 to 2,261 ft) for the chirp 

subbottom profiler and from 337 to 450 m (1,106 to 1,476 ft) for side-scan sonar. 

3.3.1.4. Discussion and Conclusions 

Among the representative electromechanical sources, boomers and multibeam depth sounders pose 

the smallest risk of auditory impacts to marine mammals. Under all scenarios modeled, the 180-dB radius 

for both sources is estimated to be <50 m (160 ft) for the nominal source level and <5 m (16 ft) when 

pulse duration is taken into account. Based on the Southall criteria, the predicted injury radius would be 

zero for both sources. In addition, the operating frequency of the representative multibeam depth sounder 

is beyond the range of all three cetacean groups. (Some multibeam depth sounders use different 

frequencies that are within the cetacean hearing range, but the system modeled here is considered 

representative of the equipment likely to be used during HRG surveys for renewable energy and marine 

minerals sites.) 

Both the representative side-scan sonar and chirp subbottom profiler could be detectable by 

cetaceans, depending on the operating frequencies selected. The side-scan sonar operating at 100 kHz 

would be detectable and the 180-dB radius is estimated to be 128-192 m (420-630 ft) based on the 

nominal source level and 65-96 m (213-315 ft) when the short pulse length is taken into account. The 

chirp subbottom profiler operating at either 3.5 kHz or 12 kHz would be detectable and the 180-dB radius 

is estimated to be 32-42 m (105-138 ft) based on the nominal source level and 26-35 m (85-115 ft) when 

the short pulse length is taken into account. Based on the Southall criteria, predicted injury ranges are 

less than 10 m (33 ft) for both sources. 

Depending on the suite of equipment selected and the operating frequencies selected, there may be no 

Level A or B harassment of marine mammals. For example, if a survey uses side-scan sonar at 400 kHz, 

chirp subbottom at 200 kHz, multibeam depth sounder at 240 kHz, and no boomer, then no acoustic 

harassment of marine mammals would be expected. 

For surveys with one or more sources operating at frequencies within the cetacean hearing range, if 

source levels are low enough, it may be feasible to monitor the entire 160-dB radius. In that case, both 

Level A and B harassment would be prevented and it would be reasonable to assume that no Incidental 
Existing Regulations, Protective Measures, and Mitigation C-15 

Take Authorization (ITA) may be needed. For example, a source level of 206 dB re 1μPa would have a 

160-dB radius of 200 m (656 ft) (based on the simplistic assumption of spherical spreading). 

Sea turtles are unlikely to hear the electromechanical sources except perhaps the boomer at very close 

range (e.g., the 180-dB radius is 38-45 m). Vessel strike avoidance measures already included in the 

Programmatic EIS include a recommended separation distance of 45 m (150 ft) for sea turtles. Therefore, 

the protocol does not include an exclusion zone or shutdown requirements for sea turtles. However, the 

exclusion zone would be initially clear of sea turtles prior to startup. 

3.3.1.5. Practical Considerations 

The BOEM expects that a 200-m (656-ft) radius exclusion zone can be effectively monitored from the 

types of coastal survey vessels expected to be used for HRG surveys of renewable energy and marine 

minerals sites. The operational ranges for these HRG surveys would be approximately <25 mi from shore 

and in water <30 m (98 ft) deep. Unlike the large, dedicated vessels used for oil and gas seismic surveys, 

coastal survey vessels may not have a bridge or elevated viewing platform, and their capability for 

effectively monitoring a radius larger than a few hundred meters would depend on vessel size and 

configuration. An exclusion zone radius of 200 m (656 ft) would encompass the 180-dB Level A 

harassment radius calculated for all of the representative electromechanical sources included in this 

Programmatic EIS as summarized above. Depending on the source levels of the equipment used on 

particular surveys, this radius may also encompass the 160 dB Level B harassment zone. The BOEM 

anticipates that if an operator can effectively monitor the 160-dB zone to prevent both Level A and B 

harassment of marine mammals, it would be reasonable to assume that an ITA under the MMPA may not 

be necessary for that particular survey. Therefore, the protocol would allow an operator to monitor a 

radius larger than 200 m (656 ft) if the operator demonstrates that it can be effectively monitored. 

Ramp-up is not expected to be an effective mitigation measure for HRG surveys because 

electromechanical sources typically are either on or off and are not powered up gradually. 

Geophysical operators report that dolphins frequently approach and chase the side-scan sonar towfish. 

Therefore, requiring a shutdown for dolphins could significantly increase survey duration or even make it 

impossible to complete some HRG surveys. The protocol requires that the exclusion zone be initially 

clear of all marine mammals and specifies shutdown for any marine mammal entering the exclusion zone. 

However, the protocol includes an exception for dolphins that approach the vessel or towed equipment at 

a speed and vector that indicates voluntary approach to bow-ride or chase towed equipment. If a dolphin 

voluntarily moves into the exclusion zone after the active acoustic sound sources are operating, it is 

reasoned that the sound pressure level is not negatively affecting that particular animal. 

3.3.2. Protocol Requirements 

1. All HRG surveys must comply with requirements for vessel strike avoidance as 

detailed in separate guidance in Chapter 3.4. The recommended separation distance 

for North Atlantic right whales of 457 m (1,500 ft) would remain in effect during 

HRG surveys since it exceeds the exclusion zone radius specified below. 

Recommended separation distances for other whales and small cetaceans are less 

than, and would be superseded by, the exclusion zone radius. The exclusion zone 

must be initially clear of sea turtles as indicated below, but thereafter the vessel strike 

separation distance of 45 m (150 ft) for sea turtles would be maintained. 

2. One protected species observer would be required on watch aboard HRG survey 

vessels at all times during daylight hours (dawn to dusk – i.e., from about 30 min 

before sunrise to 30 min after sunset) when survey operations are being conducted, 

unless conditions (fog, rain, darkness) make sea surface observations impossible. If 

conditions deteriorate during daylight hours such that the sea surface observations are 

halted, visual observations must resume as soon as conditions permit. Ongoing 

activities may continue but may not be initiated under such conditions (i.e., without 

appropriate pre-activity monitoring). Operators may engage trained third party 

observers, utilize crew members after training as observers, or use a combination of 

both third party and crew observers. 
C-16 Atlantic G&G Programmatic EIS 

3. The following additional requirements apply only to HRG surveys in which one or 

more active acoustic sound sources will be operating at frequencies less than 

200 kHz. 

a. A 200-m (656-ft) radius exclusion zone will be monitored around the survey 

vessel. If the exclusion zone does not encompass the 160-dB Level B harassment 

radius calculated for the acoustic source having the highest source level, BOEM 

will consult with NMFS about additional requirements. On a case-by-case basis, 

BOEM may authorize surveys having an exclusion zone larger than 200 m 

(656 ft) to encompass the 160-dB radius if the applicant demonstrates that it can 

be effectively monitored. 

b. Active acoustic sound sources must not be activated until the protected species 

observer has reported the exclusion zone clear of all marine mammals and sea 

turtles for 30 min. 

c. Except as noted in (d) below, if any marine mammal is sighted within or 

transiting towards the exclusion zone, an immediate shutdown of the equipment 

will be required. Subsequent restart of the equipment may only occur following 

clearance of the exclusion zone for 30 min. 

d. Shutdown would not be required for dolphins approaching the vessel or towed 

equipment at a speed and vector that indicates voluntary approach to bow-ride or 

chase towed equipment. If a dolphin voluntarily moves into the exclusion zone 

after the active acoustic sound sources are operating, it is reasoned that the sound 

pressure level is not negatively affecting that particular animal. 

The HRG surveys of renewable energy and marine minerals sites in the SMAs for the North Atlantic 

right whale would be reviewed on a case-by-case basis, and authorizations may include additional 

mitigation and monitoring requirements to avoid or reduce impacts on right whales. 

3.4. GUIDANCE FOR VESSEL STRIKE AVOIDANCE

All authorizations for shipboard surveys would include guidance for vessel strike avoidance. The 

guidance would be similar to Joint BOEM-BSEE NTL 2012-G01 (“Vessel Strike Avoidance and 

Injured/Dead Protected Species Reporting”) (USDOI, BOEM and BSEE, 2012b) which incorporates the 

NMFS “Vessel Strike Avoidance Measures and Reporting for Mariners” addressing protected species 

identification, vessel strike avoidance, and injured/dead protected species reporting. Key elements of the 

guidance are as follows: 

1. Vessel operators and crews must maintain a vigilant watch for marine mammals and 

sea turtles and slow down or stop their vessel to avoid striking protected species. 

2. When whales are sighted, maintain a distance of 91 m (300 ft) or greater from the 

whale. If the whale is believed to be a North Atlantic right whale, the vessel must 

maintain a minimum distance of 457 m (1,500 ft) from the animal (50 CFR 224.103). 

3. When sea turtles or small cetaceans are sighted, the vessel must maintain a distance 

of 45 m (150 ft) or greater whenever possible. 

4. When cetaceans are sighted while a vessel is underway, the vessel must remain 

parallel to the animal’s course whenever possible. The vessel must avoid excessive 

speed or abrupt changes in direction until the cetacean has left the area. 

5. Reduce vessel speed to 10 kn (18.5 km/h) or less when mother/calf pairs, pods, or 

large assemblages of cetaceans are observed near an underway vessel when safety 

permits. A single cetacean at the surface may indicate the presence of submerged 

animals in the vicinity of the vessel; therefore, precautionary measures should always 

be exercised. 

6. Whales may surface in unpredictable locations or approach slowly moving vessels. 

When animals are sighted in the vessel’s path or in close proximity to a moving 

vessel, the vessel must reduce speed and shift the engine to neutral. The engines 

must not be engaged until the animals are clear of the area. 
Existing Regulations, Protective Measures, and Mitigation C-17 

7. Vessel crews would be required to report sightings of any injured or dead marine 

mammals or sea turtles to BOEM and NMFS within 24 hr, regardless of whether the 

injury or death was caused by their vessel. 

In addition, vessel operators would be to required to comply with the NMFS marine mammal and sea 

turtle viewing guidelines for the Northeast Region (USDOC, NMFS [2011a] for surveys offshore 

Delaware, Maryland, or Virginia) or the Southeast Region (USDOC, NMFS [2011b] for surveys offshore 

North Carolina, South Carolina, Georgia, or Florida) or combined guidance if recommended by NMFS. 

These measures are meant to reduce the potential for vessel harassment or collision with marine mammals 

or sea turtles regardless of what activity a vessel is engaged in. 

The guidance will also incorporate the NMFS Compliance Guide for the Right Whale Ship Strike 

Reduction Rule (50 CFR 224.105), which limits vessel speed to 18.5 km/h (10 kn) in the Mid-Atlantic 

and Southeast U.S. SMAs for North Atlantic right whales during migration (Figure C-3). Vessel speed 

restrictions in these areas are in effect between November 1 and April 30 in the Mid-Atlantic and between 

November 15 and April 15 in the southeast U.S. 

3.5. GUIDANCE FOR MARINE DEBRIS AWARENESS

All authorizations for shipboard surveys would include guidance for marine debris awareness. The 

guidance would be similar to BSEE’s NTL 2012-G01 (“Marine Trash and Debris Awareness and 

Elimination”) (USDOI, BSEE, 2012). All vessel operators, employees, and contractors actively engaged 

in G&G surveys must be briefed on marine trash and debris awareness elimination as described in this 

NTL except that BSEE will not require applicants to undergo formal training or post placards. The 

applicant will be required to ensure that its employees and contractors are made aware of the 

environmental and socioeconomic impacts associated with marine trash and debris and their 

responsibilities for ensuring that trash and debris are not intentionally or accidentally discharged into the 

marine environment where it could affect protected species. The above-referenced NTL provides 

information that applicants may use for this awareness training. 

3.6. AVOIDANCE OF SENSITIVE SEAFLOOR RESOURCES

A basic mitigation philosophy for BOEM is to mitigate by avoidance. That is, this Agency must 

know enough about the nature of the seafloor area where activities are proposed so that the activities can 

be moved or offset to another area if sensitive resources are already there. This principle applies to 

sensitive cultural resources such as shipwrecks and prehistoric archaeological resources as well as 

sensitive benthic communities, and it applies to G&G activities in all three program areas. 

3.6.1. Avoidance and Reporting of Historic and Prehistoric Sites 

The BOEM and BSEE would require site-specific information regarding potential archaeological 

resources prior to approving any G&G activities involving seafloor-disturbing activities or placement of 

bottom-founded equipment or structures in the AOI. The BOEM and BSEE would use this information to 

ensure that physical impacts to archaeological resources do not take place. 

All authorizations for G&G activities that involve seafloor-disturbing activities would include 

requirements for operators to report suspected historic and prehistoric archaeological resources to BOEM 

and BSEE and take precautions to protect the resource. The requirements are expected to be similar to 

NTL 2005-G07 (“Archaeological Resource Surveys and Reports”) (USDOI, MMS, 2005), the 

enforcement for which is shared between BOEM and BSEE. The BOEM and BSEE also require 

reporting and avoidance for any previously undiscovered suspected archaeological resource and 

precautions to protect the resource from operational activities while appropriate mitigation measures are 

developed. Regulations have been promulgated based on the National Historic Preservation Act (NHPA) 

(16 U.S.C. 470 et seq.), especially Sections 106 and 110; the Archaeological Resources Protection Act 

(ARPA) of 1979 (16 U.S.C. 470), which prohibits the excavation and removal of items of archaeological 

interest from Federal lands without a permit; and the Antiquities Act of 1906 (16 U.S.C. 431). Under the 

oil and gas regulations, archaeological resource surveys are required as by 550.203(o), 550.204(s), and 

550.1007(a)(5), and an archaeological resource report is required by 550.203(b)(15), 550.204(b)(8)(v)(A), 
C-18 Atlantic G&G Programmatic EIS 

and 550.1007(a)(5). These existing regulations are applicable to all G&G operations that involve 

seafloor-disturbing activities, including coring, grab sampling, and placement of bottom cables or nodes. 

Equivalent information needs to be provided for renewable energy and marine minerals programs, 

although equivalent regulations do not expressly exist for renewable energy or for marine minerals. The 

equivalent is provided through guidance, supported by regulation and/or statutory authority (see NHPA 

Section 106, OCSLA, and 30 CFR 585 and 580). 

If an operator discovers any archaeological resource while conducting operations authorized under a 

lease or pipeline right-of-way, operations within or that may affect the discovery must be immediately 

halted the discovery reported to BOEM and BSEE. If BOEM determines that the resource is significant, 

based on criteria under the NHPA, BSEE, in consultation with BOEM, will direct how the resource is to 

be protected during operations and activities. If BOEM determines that the resource is not significant, 

BOEM will so advise BSEE. The BSEE informs the operator when operations may resume (30 CFR 

250.194). 

3.6.2. Avoidance of Sensitive Benthic Communities 

The BOEM will require site-specific information regarding sensitive benthic communities (including 

hard/live bottom areas, deepwater coral communities, and chemosynthetic communities) prior to 

approving any G&G activities involving seafloor-disturbing activities or placement of bottom-founded 

equipment or structures in the AOI. All authorizations for seafloor-disturbing activities will be subject to 

restrictions to protect corals and hard/live bottom resources, including requirements for mapping and 

avoidance, as well as pre-deployment photographic surveys of areas where bottom-founded 

instrumentation and appurtenances are to be deployed. 

The BOEM has not designated specific benthic locations for avoidance in the AOI. However, likely 

areas for avoidance would include known hard/live bottom areas; known deepwater coral locations 

including Lophelia and Oculina coral sites; deepwater coral Habitat Areas of Particular Concern 

(HAPCs); deepwater Marine Protected Areas (MPAs); Gray’s Reef National Marine Sanctuary (NMS); 

the Charleston Bump area; and the walls of submarine canyons. These benthic features are discussed in 

Chapter 4.2.1.1.2 of the Programmatic EIS. All authorizations for G&G surveys proposed within or near 

these areas would be subject to the review noted above to facilitate avoidance. 

The BOEM has not developed specific buffer zones for sensitive benthic communities in the Atlantic, 

but it is expected that they would be similar to those that BOEM uses in the Gulf of Mexico, where the 

locations of many sensitive bottom communities are known and there is a long history of bottom 

surveying in association with oil and gas exploration and production. In the Gulf of Mexico, sensitive 

benthic features in water depths less than 300 m (~1,000 ft) are protected by NTL 2009-G39 

(“Biologically-Sensitive Underwater Features and Areas”) (USDOI, MMS, 2009a) and features in greater 

water depths are protected by NTL 2009-G40 (“Deepwater Benthic Communities”) (USDOI, MMS, 

2009b). Large topographic features, such as the Flower Garden Banks and similar offshore “banks” are 

defined by “No Activity Zones” where no bottom-disturbing activity may take place within 152 m 

(500 ft). No seafloor-disturbing activities can occur within 30 m (100 ft) of “pinnacle trend” hard/live 

bottom features that have vertical relief of 2.4 m (8 ft) or more. Avoidance of low-relief hard/live bottom 

features is required but no buffer distance is specified; plans proposing activities near these areas must 

include survey coverage extending to 1,000 m (3,280 ft) from the location of proposed bottom-disturbing 

activity. For high-density deepwater benthic communities (including chemosynthetic and deepwater coral 

communities), setbacks of 610 m (2,000 ft) are required for drilling discharge locations and 76 m (250 ft) 

from the location of all other proposed seafloor disturbances. The application of similar setbacks as 

default buffer zones would be expected when G&G activities take place in the AOI. 

3.7. GUIDANCE FOR ACTIVITIES IN OR NEAR NATIONAL MARINE SANCTUARIES

There are two NMSs within the AOI: Monitor and Gray’s Reef (see Chapter 4.2.11.1.1 of the 

Programmatic EIS for brief descriptions). The BOEM would not authorize seafloor-disturbing activities 

within the boundaries of an NMS. Seafloor-disturbing activities proposed near the boundaries of an NMS 

would be assigned a setback distance as a condition of permit approval to be determined at the time the 

action is before BOEM and in consultation with the Sanctuary Manager. Setbacks of 152 m (500 ft) for 

seafloor-disturbing activities would be expected that could be modified by consultations with NOAA 
Existing Regulations, Protective Measures, and Mitigation C-19 

under the NMSA for specific activities in proximity to an NMS. Chapter 1.6.15 of the Programmatic 

EIS provides information about the NMSA consultation process. 

All BOEM authorizations for G&G activities would include instructions to minimize impacts on 

NMS resources. Operators proposing to conduct activities within or near the boundaries of Monitor NMS 

or Gray’s Reef NMS would be instructed to exercise caution to ensure that such activities do not endanger 

any other users of the Sanctuary. Additionally, if proposed activities involve seafloor-disturbing activities 

near an NMS or moving the surface marker buoys for the Sanctuary, the operator would be required to 

contact the Sanctuary Manager for instructions. 

Existing Federal regulations for Monitor NMS (15 CFR 922.61) prohibit certain activities including 

(but not limited to) anchoring, stopping, remaining, or drifting without power at any time; any type of 

subsurface salvage or recovery operation; diving of any type, whether by an individual or by a 

submersible; lowering below the surface of the water any grappling, suction, conveyor, dredging or 

wrecking device; detonating below the surface of the water any explosive or explosive mechanism; 

drilling or coring the seabed; lowering, laying, positioning or raising any type of seabed cable or 

cable-laying device; trawling; or discharging waste material into the water in violation of any Federal 

statute or regulation. 

Existing Federal regulations for Gray’s Reef NMS (15 CFR 922.92) prohibit certain activities 

including (but not limited to) anchoring; dredging; drilling; using explosives; breaking, damaging, or 

removing any bottom formation; constructing structures; constructing, placing, or abandoning any 

structure, material, or other matter on the submerged lands of the Sanctuary; and discharging or 

depositing any material or other matter except fish or fish parts, bait, or chumming materials, effluent 

from marine sanitation devices, and vessel cooling water. Under a new regulation that went into effect 

December 4, 2011, the southern third of the NMS is now a research area where fishing and diving is 

prohibited but vessels are allowed to travel across the area as long as they don't stop (Federal Register, 

2011; Office of National Marine Sanctuaries, 2011). 

3.8. GUIDANCE FOR MILITARY AND NASA COORDINATION

All authorizations for permitted activities would include guidance for military and National 

Aeronautics and Space Administration (NASA) coordination. The guidance would be similar to NTL 

2009-G06 (“Military Warning and Water Test Areas”) (USDOI, MMS, 2009c). All vessel operators and 

contractors actively engaged in G&G surveys and permitted activities would be required to establish and 

maintain early contact and coordination with the appropriate military command headquarters or NASA 

point of contact (POC), in order to avoid or minimize the effects of conflicts with potentially hazardous 

military operations. In addition, the placement, location, and planned periods of operation of any surface 

structures would be subject to BOEM approval. When command headquarters determines it is necessary 

the vessel operator would be required to enter into a formal Operating Agreement that delineates the 

specific requirements and parameters for the operator’s activities. 

4. ADDITIONAL PROTECTIVE MEASURES INCLUDED IN 

ALTERNATIVE B 

The following protective measures in Alternative B would be identical to those previously described 

for the Proposed Action (Alternative A): 

 HRG survey protocol (renewable energy and marine minerals sites); 

 guidance for vessel strike avoidance guidance; 

 guidance for marine debris awareness; 

 avoidance and reporting of historic and prehistoric sites; 

 avoidance of sensitive benthic communities; 

 guidance for activities in or near National Marine Sanctuaries; and 

 guidance for military and NASA coordination. 
C-20 Atlantic G&G Programmatic EIS 

Alternative B would include the additional or revised measures listed below and described in the 

following subsections: 

 an expanded time-area closure for North Atlantic right whales; 

 a time-area closure for nesting sea turtles offshore Brevard County, Florida; 

 limitations on concurrent seismic surveys; and 

 a seismic airgun survey protocol with required use of PAM. 

4.1. EXPANDED TIME-AREA CLOSURE FOR NORTH ATLANTIC RIGHT WHALES 

Under Alternative B, the time-area closure for North Atlantic right whales would be expanded to a 

continuous 37-km (20-nmi) wide zone extending from Delaware Bay to the southern limit of the AOI 

(Figure C-4). The expanded closure zone would fill gaps in coverage between Delaware Bay and 

Wilmington, North Carolina where the Mid-Atlantic SMA is discontinuous. It would also cover areas 

offshore Florida adjacent to the right whale critical habitat between the Southeast SMA and the southern 

boundary of the AOI. The expanded closure area would add 6,823,753 ac (27,615 km2

) to the SMA 

closure areas described under Alternative A, totaling 14,413,356 ac (58,329 km2

) and representing 

7 percent of the total AOI (vs. approximately 4 percent under Alternative A). 

The purpose of the expanded time area closure is to prevent impacts to right whales along their entire 

migration route and calving and nursery grounds. The SMAs do not provide continuous coverage of the 

right whale migratory route along the Mid-Atlantic coast because they focus on areas of heavy ship traffic 

(including entrances to certain bays and ports). Sightings data reviewed by NMFS in developing the ship 

strike rule indicate that approximately 83 percent of right whale sightings occur within 37 km (20 nmi) of 

the coast. The expanded time-area closure under Alternative B would form a continuous zone of the same 

width along the coast of the AOI (Figure C-4). 

Under the expanded time-area closure, no G&G surveys using air guns would be authorized within 

the right whale critical habitat area from November 15 through April 15 nor within the Mid-Atlantic and 

Southeast U.S. Seasonal Management Areas (SMAs) and the expanded closure areas during the times 

when vessel speed restrictions are in effect under the Right Whale Ship Strike Reduction Rule (50 CFR 

224.105). However, HRG surveys proposed in the critical habitat area, SMAs, and the expanded areas 

may be considered on a case-by-case basis only if: (1) they are proposed for renewable energy or marine 

minerals operations; and (2) they use acoustic sources other than air guns. The coincidence is necessary 

because of other biological use windows or project monitoring requirements. Any such authorization 

may include additional mitigation and monitoring requirements to avoid or significantly reduce impacts 

on right whales. Other supporting surveys (e.g., biological surveys) would not be affected by this 

restriction. 

Exceptions to the right whale time-area closure could occur if a survey was needed to serve important 

operational or monitoring requirements for a particular project. For example, monitoring surveys for 

renewable energy (e.g., scour, cable burial) might need to take place at fixed intervals to capture seasonal 

changes or safety-related conditions. Another example would be a marine minerals project in which 

dredging is not seasonally restricted and real-time bathymetry data must be collected to track dredging 

operations or pre- and post-bathymetric surveys must be collected immediately before or after dredging to 

establish volumes borrowed. 

4.2. TIME-AREA CLOSURE FOR NESTING SEA TURTLES OFFSHORE BREVARD 

COUNTY, FLORIDA

Alternative B would include a time-area closure in near-coastal waters offshore Brevard County, 

Florida during the sea turtle nesting season (May 1 to October 31) (Figure C-4). No airgun surveys 

would be authorized within the closure area during this time. Other non-airgun surveys in the closure 

area, including HRG surveys of renewable energy and marine minerals sites, would be reviewed on a 

case-by-case basis, and authorizations may include additional mitigation and monitoring requirements to 

avoid or reduce impacts on sea turtles. 

The Brevard County time-area closure would include the portion of Brevard County that is within the 

AOI and would extend 11 km (5.9 nmi) offshore (Figure C-5). The southern border of Brevard County 
Existing Regulations, Protective Measures, and Mitigation C-21 

is beyond the southern boundary of the AOI. The closure would also extend radially from the northern 

county boundary at the shoreline. The extent is based on acoustic modeling of distances that could 

receive sound pressure levels of 160 dB re 1 μPa from a large airgun array in this area. 

The purpose of the closure would be to avoid disturbing the large numbers of loggerhead turtles (and 

hatchlings) that are likely to be present in nearshore waters of Brevard County during turtle nesting and 

hatching season. Brevard County includes some of the world's most important nesting beaches for sea 

turtles. During the 2010 nesting season, there were over 31,000 loggerhead nests in Brevard County. The 

Archie Carr National Wildlife Refuge (ACNWR), located mainly within Brevard County, has been 

identified as the most important nesting area for loggerhead turtles in the western hemisphere. The 

ACNWR is critical to the recovery and survival of loggerhead turtles; it has been estimated that 

25 percent of all loggerhead nesting in the U.S. occurs in the ACNWR. Nesting densities have been 

estimated at 625 nests per km (1,000 nests per mile) within the ACNWR. 

The sea turtle time-area closure would overlap with the right whale time-area closure (Figure C-5). 

The overlapping area would be under closure most of the year (November 15 – April 15 for right whales 

and May 1 – October 31 for sea turtles). The right whale critical habitat area, the SMAs and expanded 

right whale closure areas, and the sea turtle closure area would be closed only to surveys deploying 

airguns, such as seismic surveys for oil and gas exploration and HRG surveys for oil and gas leases. 

Other activities such as HRG surveys for renewable energy or marine minerals programs could occur; as 

noted previously, applications would be reviewed on a case-by-case basis, and authorizations may include 

additional mitigation and monitoring requirements. 

4.3. SEPARATION BETWEEN SIMULTANEOUS SEISMIC AIRGUN SURVEYS

Alternative B would establish a 40 km (25 mi) separation distance between simultaneously operating 

deep-penetration seismic surveys. This is in contrast to Alternative A, which does not require any 

geographic separation of concurrent seismic surveys. However, in practice, operators typically maintain a 

separation of about 17.5 km (9.5 nmi) between concurrent surveys to avoid interference (i.e., overlapping 

reflections received from multiple source arrays). The separation distance under Alternative B was 

created by rounding up this typical “operational” separation distance to 20 km (10.8 nmi), then doubling 

it. 

The purpose of this measure is to limit ensonification of large areas of the AOI at the same time by 

specifying a conservative separation distance between simultaneous surveys. The largest exposure radii 

estimated for the 160 dB threshold for a large airgun array is approximately 15 km (8 nmi) 

(Appendix D). This operational separation requirement would be included as part of OCSLA 

authorizations (i.e., through lease stipulations, permits, conditions for plan approvals [for example, a 

renewable energy Construction and Operations Plan], and NTLs for existing leases). 

4.4. SEISMIC AIRGUN SURVEY PROTOCOL WITH REQUIRED USE OF PASSIVE 

ACOUSTIC MONITORING

Under Alternative B, the use of PAM would be required as part of the seismic airgun survey protocol 

(rather than optional or “encouraged” as in Alternative A). The purpose would be to improve detection of 

marine mammals prior to and during seismic airgun surveys so that impacts can be avoided by shutting 

down or delaying startup of airgun arrays until the animals are outside the exclusion zone. 
C-22 Atlantic G&G Programmatic EIS 

Figure C-4. Time-Area Closures under Alternative B. 
Existing Regulations, Protective Measures, and Mitigation C-23 

Figure C-5. Close-Up View of Time-Area Closures Offshore Brevard County under Alternative B. 
C-24 Atlantic G&G Programmatic EIS 

5. OTHER MITIGATION AND MONITORING MEASURES 

CONSIDERED BUT NOT SELECTED 

5.1. EXPANDED EXCLUSION ZONE (160 DB) 

The seismic airgun survey protocol (see Attachment) includes an exclusion zone based on the range 

at which animals could be exposed to a received sound pressure level of 180 dB re 1 μPa, which is the 

current NMFS criterion for Level A harassment of cetaceans. The BOEM also considered establishing an 

exclusion zone based on a received sound pressure level of 160 dB re 1 μPa, which is the current NMFS 

criterion for Level B harassment of cetaceans. The purpose of this larger zone would be to avoid most 

Level B harassment of marine mammals. Based on calculations in Appendix D as summarized in 

Table C-6, this zone could extend up to 15 km (9.3 mi) from a large airgun array (5,400 in3

) and up to 

3 km (1.9 mi) from a small airgun array (90 in3

) depending on the geographic location and season 

modeled. The mean distances were 8.5 km (5.3 mi) for a large airgun array and 1.9 km (1.2 mi) for a 

small airgun array. 

Table C-6 

 

Estimated Ranges (m) for Level B Harassment of Cetaceans by Airgun Arrays 

Based on the NMFS 160-dB Criterion 

Current NMFS 

Level B Criterion 

160 dB re 1 μPa (rms) Equipment Number of Scenarios 

Modeled Statistics 

Rmax R95%

Min (m) 5,184 4,959 

5,400 in Max (m) 15,305 9,122 3 Airgun Array 21 

Mean (m) 8,679 6,856 

Min (m) 1,294 1,100 

90 in Max (m) 3,056 2,519 3 Airgun Array 35 

Mean (m) 1,919 1,684 

Rmax is the maximum received sound pressure level. R95% is the received level over 95% of the energy of the pulse. 

Source: Appendix D. 

The BOEM has determined that it is not feasible to routinely require monitoring of a 160-dB 

exclusion zone for seismic surveys using shipboard protected species observers. Effective monitoring of 

a larger, 160-dB exclusion zone may be feasible for some surveys if the 160-dB radius is small enough, 

but in many cases it would require a combination of techniques in addition to shipboard protected species 

observers. These could include aerial monitoring using manned or unmanned aircraft. As explained in 

Chapter 4.4, in current practice those techniques have significant limitations and disadvantages, given 

the geographic scope of the proposed action. The BOEM has determined that it is not currently feasible 

to require a combination of shipboard and aerial surveys on a routine basis to effectively monitor a 

160-dB exclusion zone. 

Although 160 dB is the current criterion for Level B harassment of cetaceans by impulsive sources, 

there is much variability and ongoing research about the levels of received sound that can cause 

behavioral responses in marine mammals, as well as the biological significance of those responses 

(National Research Council, 2005; Southall et al., 2007; Ellison et al., 2011). Also, although the 

exclusion zone included in the proposed action would not prevent Level B harassment of marine 

mammals, other measures such as the time-area closure for North Atlantic right whales (Chapter 3.1) 

would help to reduce the risk of those impacts. 
Existing Regulations, Protective Measures, and Mitigation C-25 

5.2. PASSIVE ACOUSTIC MONITORING

The seismic airgun survey protocol based on encourages, but does not require, the use of PAM to 

supplement visual observations during monitoring of the exclusion zone (see Attachment). 

There are two types of PAM systems in current use: fixed PAM and towed systems. Fixed systems 

have the capability to monitor underwater sounds over a wide range of spatial and temporal scales. There 

are three categories of fixed systems: autonomous recorders, radio-linked hydrophones, and fixed cable 

hydrophones. Autonomous recorders acquire and store acoustic data internally and are deployed 

semi-permanently underwater via a mooring or buoy and must be retrieved to access the data. They are 

capable of continuous recording, automatic detection/classification of sounds, and collection of 

non-acoustic data. Radio-linked hydrophone systems consist of hydrophones that are moored or fixed to 

the bottom and transmit the audio signal via radio waves to a receiving station on shore. The acoustic 

data can be monitored and processed in real or near-real time, or post-processed; however, these data are 

limited by bandwidth, range of transmission, and data transfer rates. Fixed cable hydrophone systems are 

typically located on the seafloor in a permanent configuration and can continuously send data to a 

receiving station. Fixed PAM systems are typically used for monitoring of marine mammals prior to a 

noise-generating activity (i.e., pile driving, offshore liquefied natural gas facility operation) at a fixed 

location (Bingham, 2011). For example, the Navy uses a fixed PAM system to monitor their test ranges. 

Towed PAM systems were an early configuration applied to monitoring of marine mammals and are 

used with seismic airgun surveys and for close-range mitigation of the effects of other mobile activities. 

Towed arrays have the advantage of mobility and large spatial coverage, and therefore can be used for 

monitoring when the active source is mobile or covering a large spatial area. However, these systems 

have limited directional capabilities and challenges from both sound sources and the receivers being 

mobile. In addition, the towed systems have short time coverage, limited detection range, and are prone 

to masking problems from vessel noise, flow noise, and seismic source noise, including reverberation in 

shallow water. They also have limitations from ship availability, can be readily damaged, have 

difficulties localizing whale calls, and are difficult for use for detection in front of the vessel. Some of 

these limitations can be overcome, and new technology is being developed (e.g., vector sensors that can 

measure angles from a single point and assist with determining a more precise bearing of the animal) 

(Bingham, 2011). Every installation must be designed on a case-by-case basis given the requirements, 

environment, and resources available, and will need to consider the technological limitations to determine 

the best method for PAM, which will still need to be used in conjunction with visual observers, as PAM 

can be conducted at night when visual observations are not possible. 

The software and hardware technologies for PAM currently exists that can perform many marine 

mammal monitoring and mitigation requirements under a wide range of operational conditions. However, 

these existing systems were not designed specifically for monitoring and mitigation for the offshore 

industrial application. No single technical approach has the ability to satisfy all or even most of the 

marine mammal monitoring and mitigation requirements of the offshore industry, and most likely an 

integrated approach is necessary. In addition, one of the limitations of PAM is that it works only if the 

animals produce sound that can be detected by the system; there are cryptic species of marine mammals 

that do not vocalize much or at all. Also, PAM is unable to simultaneously listen to all species in an area 

due to the wide range of frequencies of vocalizations. The PAM operators must be trained and 

experienced in order to successfully operate the systems. Fixed PAM technologies are more mature than 

towed PAM for mitigation and monitoring of marine mammals for the offshore industry. However, 

towed PAM has been used with some success to supplement visual monitoring of exclusion zones 

(Bingham, 2011). Towed arrays have been used primarily for sperm whale work, although they have the 

disadvantage of not being able to see straight ahead or through the ship unless the array is towed deeper 

than the bottom of the vessel. 

Although the technology for detecting and locating underwater sounds and their sources in general is 

well developed, integrated hardware and software systems using acoustics specifically designed to locate 

and track marine mammals as mitigation for seismic airgun surveys are relatively new and have only been 

commercially available in recent years. 

Currently, BOEM strongly encourages but does not require the use of PAM for seismic airgun 

surveys in the Gulf of Mexico (USDOI, BOEM and BSEE, 2012b). Under Joint BOEM-BSEE NTL 

2012-G02 (“Implementation of Seismic Survey Mitigation Measures and Protected Species Observer 

Program”), PAM can be used to allow ramp-up during low visibility conditions when ramp-up would 
C-26 Atlantic G&G Programmatic EIS 

otherwise not be allowed. Canada and New Zealand have similar provisions, but no country requires 

routine use of PAM (Blue Planet Marine, 2010). 

5.3. ACTIVE ACOUSTIC MONITORING

Active acoustic monitoring (AAM) is a method of determining the presence of marine mammals that 

use sonar. The AAM can potentially detect non-vocalizing marine mammals, whereas PAM can detect 

only vocalizing animals. However, there a number of significant issues with AAM, including that AAM 

systems transmit acoustic energy that may disturb marine mammals by influencing their behavior, and a 

separate permit may be necessary for its use (Bingham, 2011). 

Active sonar produces a short sound pulse (energy) from a high power source (transducer) that travels 

through the water, reflects off objects, and travels back to a hydrophone receiver. The time it takes for the 

sound to travel to and from the target is easily computed from the difference in time that the source 

“ping” was sent and the time the reflected returning sound is measured. This travel time multiplied by the 

speed of sound in water divided by two is the approximate distance to the target. Bearing and range from 

the ship (or some other platform) can be converted to an absolute position on a map, given the ship 

position and some simple geometry. This is used, for example, to map seabed features, or to discriminate 

among different objects on the seafloor and in the water. 

Potential problems with the use of AAM include standard sonar problems of reverberations and 

propagation in high-clutter shallow water environments, false alarms, species classification, methods of 

deployment, and cost (Stein, 2011). In addition, while AAM can identify animals swimming at right 

angle to the sound source, it is difficult to detect animals that are directly facing toward or away from the 

AAM sound source. It is also difficult to detect animals swimming at depth or animals swimming close 

to the surface with AAM. Another operational challenge with AAM is that it does not penetrate beneath 

thermoclines or haloclines, so animals swimming below them would also not be detected by AAM 

systems that are hull-mounted. In these situations, towed AAM systems would be required. In addition, 

AAM is not very useful in very shallow water, especially in rough seas. Currently the use of AAM 

technology for mitigation and monitoring of marine mammals during offshore industry activities is less 

advanced than either fixed or towed PAM systems. However, recent testing of the technology indicates 

that it can be useful in certain circumstances (Bingham, 2011). 

There have also been some studies performed using high frequency fisheries sonar for locating 

marine mammals, killer whales in Norway in particular (Knudsen et al., 2007). These fisheries sonars 

operate at 20-30 kHz, with some operating at frequencies above 100 kHz. Most whales can detect 

frequencies in the 20-30 kHz range, but only smaller whales and dolphins can detect frequencies above 

100 kHz (Knudsen et al., 2007). One study compared results using two sonars with different operating 

ranges, one operated at 20-30 kHz and the other operated at 110-122 kHz, and determined that the lower 

frequency sonar detected killer whales up to at least a 1,500-m (4,921-ft) range, whereas the higher 

frequency sonar did not give reliable detection at ranges greater than 400 m (1,312 ft) (Knudsen et al., 

2007). However, most fish-finding sonars operate at around 30 kHz and would be good for detecting 

whales out to about 2 km (1.2 mi) and dolphins out to about 1 km (0.6 mi), but due to the frequency they 

also would be audible to all the small marine mammals and some of the larger whales. If the whale 

detection sonar is operated at frequencies that the animals might hear, the detection sonar also would need 

to be assessed as a source of disturbance, and the signal processing for species discrimination and 

potential cumulative effects would need to be addressed. 

Development of an effective active sonar system will require consideration of the behavioral 

differences among various types of marine mammals. It may be difficult to develop a single approach 

that will work well with all species. 

The BOEM has determined that it is not currently feasible to require AAM on a routine basis. 

5.4. AERIAL SURVEYS

As a mitigation measure, aerial surveys with protected species observers provide the ability to 

observe and monitor large exclusion zones that cannot be adequately monitored from a vessel. As a 

mitigation measure, aerial surveys can monitor seismic exclusion zones, and if marine mammals are seen 

from the aircraft within the appropriate exclusion zone around the seismic source vessel or heading 

toward that zone, the aerial protected species observer could notify the seismic vessel on-board personnel 
Existing Regulations, Protective Measures, and Mitigation C-27 

in order for the sighting to be monitored, tracked, and appropriate mitigation measures initiated as 

necessary. 

Aerial surveys are performed by two primary observers sitting at bubble windows on opposite sides 

of a small aircraft flying typically at 305-457 m (1,000-1,500 ft) above the surface. The observers search 

the sea surface visible through the bubble windows with the unaided eye. When a marine mammal is 

sighted, the observers record the species, number of individuals, size/sex/and age class when possible, 

activity, heading, and swimming speed category (if traveling). In addition, the observer will recorded the 

time, sightability (subjectively classified as excellent, good, moderately impaired, seriously impaired, or 

impossible), sea conditions, and sun glare (none, little, moderate, or severe) at intervals along the transect 

and at the end of each transect. 

Aerial monitoring programs have significant limitations. Practically, they are limited to nearshore 

waters where there is an airport nearby to allow for adequate survey duration to allow for less transit time 

to and from the seismic survey vessel location. They also require additional logistical coordination, are 

sensitive to weather-related interruptions, and carry safety risks to survey personnel. For example, in 

May 2008 a small aircraft conducting marine mammal surveys for a renewable energy site offshore the 

Mid-Atlantic coast crashed in New Jersey, killing two people and injuring two others (Spoto, 2008). 

Because of the significant limitations for manned aerial surveys in offshore waters due to the long 

transit times, unmanned aircraft systems (UASs) are a possibility for future use. The UASs have been 

emerging as a potential monitoring resource for detecting the presence of marine mammals during 

research as well as to meet mitigation and monitoring requirements during human activities, such as 

military sonar, seismic airgun surveys and geophysical research. A number of organizations, such as 

members of the offshore oil and gas industry, NMFS, BOEM, and the U.S. Navy, have been investigating 

the use of these surveys for a number of reasons, including but not limited to (1) unmanned surveys 

address safety concerns of putting human pilots and observers in potentially dangerous offshore areas; 

(2) unmanned aircraft can generally fly up to 20 hr, which is longer than manned surveys; (3) unmanned 

surveys can provide video data, even with high definition video cameras, which can be carefully reviewed 

post-flight rather than relying simply on visual observations during the flight; (4) unmanned surveys may 

provide for more frequent survey effort since securing personnel for flights is not necessary; and 

(5) aircraft can be launched from seismic ships. Preliminary scientific testing has been conducted by 

NMFS scientists at the National Marine Mammal Laboratory (NMML). However, NMFS has indicated 

that more testing is necessary before NMFS will give approval to its use as a mitigation or monitoring 

tool. In addition, the Federal Aviation Administration (FAA) currently prohibits use of UASs in 

U.S. airspace except under certain circumstances and with Federal sponsorship. The NMFS and BOEM 

are aware of ongoing efforts to gain FAA approval to deploy and test the UASs in order to assist in 

detecting marine mammals, but that approval is unlikely in the near future. Should the FAA grant UAS 

approval for use in offshore waters of the Atlantic Ocean, NMFS (and BOEM) would then make a final 

determination (informed by the results of additional UAS testing) on whether UASs are a practical tool to 

detect marine mammals in offshore waters in support of seismic survey monitoring programs. 

5.5. AUTONOMOUS UNDERWATER VEHICLES

Autonomous underwater vehicles (AUVs) can be used to aid in PAM. The AUVs are capable of 

monitoring at vertical and horizontal scales similar to the diving and foraging movements of the whales 

themselves (Moore et al., 2007). Another advantage of deploying PAM from AUVs or towed platforms 

is that it provides a good means of detecting vocalizing marine mammals that is less affected by sea state, 

visibility, or presence of a survey vessel (USDOC, NOAA, 2007). 

The Office of Naval Research is sponsoring studies involving five different AUVs using PAM on 

gliders. However, the results of these studies are not available at this time. One issue with using PAM on 

AUVs is that they are already slow vessels, and attaching a towed array system creates additional drag 

that slows them down further. The BOEM has determined that it is not currently feasible to use AUVs 

for monitoring seismic airgun surveys on a routine basis. 
C-28 Atlantic G&G Programmatic EIS 

6. NON-AIRGUN ALTERNATIVES AND RELATED MEASURES 

CONSIDERED BUT NOT SELECTED 

The impulsive airgun has been under scrutiny as a sound source for seismic exploration due to the 

potential impacts of underwater noise on marine life (Weilgart, 2010). Alternative acoustic source 

technologies generally put the same level of useable energy into the water as airguns, but over a longer 

period of time with a resulting lower peak sound level, i.e., they are quieter. One alternative, the low 

frequency passive seismic method, relies on naturally produced sounds and does not introduce any sound 

into the environment. These alternative acoustic sources are in various stages of development, and none 

of the systems with the potential to replace airguns as a seismic source are currently commercially 

available. However, they are discussed in detail in the technical write-up below along with 

technology-based mitigation measures that attempt to decrease the noise level of airguns. 

6.1. MARINE VIBRATORS (VIBROSEIS) 

6.1.1. Hydraulic 

In 1981, Industrial Vehicles International, Inc. (IVI) signed an agreement with Britoil to develop a 

marine vibrator seismic source. In 1983, after scrapping the first design, IVI began developing a new 

system with the goal of producing a marine source able to emit a broad band, high amplitude, modulating 

frequency output. In 1985, the first commercial system was offered (IVI, 2003). The developed system 

consists of a marine vibrator, vibrator controller, and a power unit. The marine vibrator contains a piston 

within a housing with power supplied to the electrical, pneumatic and hydraulic systems by the power 

unit. An alternator, air compressor, and two pressure-driven hydraulic pumps are driven by an air-cooled 

diesel engine. The source is capable of generating modulated frequencies between 10 and 250 Hz and can 

be used in water depths as shallow as 1 m (3 ft). Signals are generated by conventional land vibrator 

controllers (IVI, 2010). 

The system has been tested in various environments from transition zones to deepwater. Acoustic 

performance tests conducted at the Seneca Lake Facility of the Naval Underwater Systems Center in 1988 

evaluated the system and determined that the marine vibrator was deficient in the low frequencies 

(Johnston, 1989; Walker et al., 1996). A comparison of marine vibrator, dynamite, and airgun sources in 

southern Louisiana concluded that the marine vibrator was a viable source for environmentally sensitive 

areas (Potter et al., 1997; Smith and Jenkerson, 1998). In transition zones, when coupled with the 

seafloor, marine vibrators operate like a land vibrator (Christensen, 1989). The best performance is on a 

seafloor which distributes the vibrator’s forces. 

Initial deepwater tests were conducted in the Gulf of Mexico by Geco-Prakla using a vibrator with an 

energy output approximately equivalent to a 1,000 in3

 airgun. Despite limitations of low frequency 

energy, good definition of reflectors down to 3 s indicated that the system was viable (Haldorsen et al., 

1985). In 1996, a commercial field test comparing a six-marine-vibrator array with a single 4,258 in3

airgun was undertaken in the North Sea by Geco-Prakla with the objectives of evaluating cost, reliability, 

production rate and quality of the geophysical data. After 2 weeks of data collection, a comparison 

between the marine vibrator and the airgun data indicated that the marine vibrator data contained more 

frequency content above 30 Hz and less frequency content below 10 Hz than the airgun data, but overall 

the data were comparable. Marine vibrator production rates were slightly lower than those of the airgun, 

but by the end of the survey, the technical downtime of the marine vibrator was similar to the airgun 

(Johnson et al., 1997). 

Geco-Prakla, a subsidiary of Schlumberger, operated the marine vibrator program, conducting 

surveys and tests until 2000 when the exclusive-use agreement between IVI and Schlumberger expired 

(Bird, 2003). Industrial Vehicles International, Inc. continued to further develop the system into the early 

2000’s, but they are no longer actively marketing the product because there is no client base for the 

system. The significant expense to retrofit the marine exploration companies’ ships to support marine 

vibrators is not offset by reduced operation costs or better data quality. Industrial Vehicles International, 

Inc. presently has marine vibrator systems that could be used for seismic data collection, but they would 

require renovation prior to deployment, which could take 3 months to a year (E. Christensen, Vice 

President IVI, pers. Comm. with J. Lage, BOEM, 2010). 
Existing Regulations, Protective Measures, and Mitigation C-29 

6.1.2. Electric 

Petroleum Geo-Services (PGS) began developing an electro-mechanical marine vibrator in the late 

1990’s. The original system consists of two transducers: the lower frequency (6-20 Hz) “Subtone” 

source and the higher frequency (20-100 Hz) “Triton” source (Tenghamn, 2005, 2006). Each vibrator is 

composed of a flextensional shell that surrounds an electrical coil, a magnetic circuit and a spring 

element. The sound in the water column is generated by a current in the coil, which causes the spring 

elements and shell to vibrate. Mechanical resonances from the shell and spring elements allow very 

efficient, high power generation (Tenghamn, 2005, 2006; Spence et al., 2007). The source tow-depth, 

generally between 5 and 25 m (16 and 82 ft) below the sea surface, is selected depending on the 

frequency and enhancement from the surface reflection which, to a certain degree, directs the acoustic 

signal downwards. 

The reduction of the overall sound level and specifically the frequencies above 100 Hz, which are 

beyond the useful seismic range, is a major advantage of the system. Another is the reduction of acoustic 

power in comparison with conventional seismic sources, which occurs because the net source energy is 

spread over a long period of time (Tenghamn, 2005, 2006). 

This system was compared to a 760 in3

 airgun along a 2D line in shallow water. A comparison of the 

data demonstrates that the marine vibrator equals the penetration of the airgun down to 5.5 s two-way 

travel time while emitting less acoustic energy into the water. A second test comparing dynamite to the 

vibrators was run in the transition zone (1.2-1.8 m [4-6 ft] of water). The transducers were mounted in a 

frame that was placed on the seabed. The vibrators lost the low frequency component due to attenuation 

of the signal, limiting the depth of penetration to approximately 2 s two-way travel time. However, in the 

shallower sections imaged by the vibrator, the two sources compared favorably (Tenghamn, 2005, 2006). 

Most of the trials have been conducted in shallow water (<100 m [<328 ft]); deeper water tests need to be 

run to determine performance depth range of the system (Tenghamn, 2010). 

During the early period of development, the system proved the concept that it worked as a source for 

seismic data. However, unreliability prevented it from becoming a commercial system. Petroleum GeoServices spent 2006 and 2007 conducting a feasibility study to improve reliability and testing a newly 

developed prototype. After that work, PGS developed three additional systems that are currently being 

tested. Petroleum Geo-Services does not have a commercial system available for data collection at this 

time. They project that, if funds were available, it would take 2-4 years to fully develop and test a system 

for commercial use (R. Tenghamn, VP Innovation and Business Development PGS, pers. comm. to J. 

Lage, BOEM, 2010). 

6.2. LOW-FREQUENCY ACOUSTIC SOURCE (PATENTED) (LACS) 

Originally designed as a ship sound simulator for the Norwegian navy, the low level acoustic 

combustion source (LACS) is being promoted as an alternative source for seismic acquisition (Weilgart, 

2010). The LACS system is a combustion engine with a cylinder, spark plug, two pistons, two lids, and a 

shock absorber. It creates an acoustic pulse when two pistons push lids vertically in opposite directions; 

one wave reflects from the sea surface and combines with the downward moving wave. There is no 

bubble noise from this system as all air is vented and released at the surface, not into the underwater 

environment. The absence of bubble noise allows the system to produce long sequences of acoustic 

pulses at a rate of 11 shots per second; this allows the signal energy to be built up in time with a lower 

amount of energy put into the water (Askeland et al., 2007, 2009). The system design also controls the 

output signal waveform, which can reduce the amount of non-seismic (>100 Hz) frequencies produced 

(Spence et al., 2007). The transmitted pulses are recorded by a near-field hydrophone and seafloor and 

sediment reflections are recorded by a far-field streamer (Askeland et al., 2007, 2009).

Two LACS systems are being offered commercially. The LACS 4A has a diameter of 400 mm 

(15.7 in), a height of 600 mm (24 in), and a weight of approximately 100 kg (220 lb) in air. Pulse 

peak-peak pressure is 218 dB re 1μPa @ 1 m. Field test results of the LACS 4A system demonstrate that 

the system is capable of accurately imaging shallow sediments (~230 m [755 ft]) within a fjord 

environment (Askeland et al., 2008, 2009). This system is suitable for shallow penetration 

towed-streamer seismic surveys or vertical seismic profiling (Askeland et al., 2008). 

The second system, the LACS 8A, theoretically has the potential to compete with a conventional deep 

penetration airgun seismic array. The LACS 8A system has pulse peak-peak pressure of 3 Bar meter or 
C-30 Atlantic G&G Programmatic EIS 

230 dB re 1μPa @ 1 m. The weight is 400 kg (880 lb), and the diameter is 800 mm (31.5 in). Several 

LACS units may be operated together to provide an increased pulse pressure (Bjørge Naxys AS, 2010). 

This system currently does not exist, and the project is presently on hold. It would take at least 18 months 

to build and field test one of these systems if money came available to do so (J. Abrahamsen, Managing 

Director Bjørge Naxys, pers. comm. to J. Lage, BOEM, 2010). 

6.3. DEEP-TOWED ACOUSTICS/GEOPHYSICS SYSTEM (DTAGS) 

The Navy developed a deep-towed acoustics/geophysics system (DTAGS) to better characterize the 

geoacoustic properties of abyssal plain and other deepwater sediments. The system was tested and 

modified in the early 1990’s and used in various locations around the world until it was lost at sea in 1997 

(Gettrust et al., 1991; Wood et al., 2003). 

The second generation DTAGS is based on the original design but with more modern electronics. It 

uses the same Helmholtz resonator source consisting of five concentric piezoelectric ceramic rings sealed 

in an oil-filled rubber sleeve to generate a broadband signal greater than 2 octaves. The optimum 

frequency performance range is between 220 and 1,000 Hz with a source level of 200 dB re 1 μPa @ 1 m, 

which is a major improvement over the original DTAGS. The source is extremely flexible, allowing for 

changes in waveform and decrease in sound level to produce a source amplitude, waveform, and 

frequency to suit specific requirements (Wood et al., 2003; Wood, 2010). 

The DTAGS is towed behind a survey vessel usually at a level of 100 m (328 ft) above the seafloor 

and a vessel speed of 3.7 km/hr (2 kn); it can operate at full ocean depths (6,000 m [19,685 ft]). A 450-m 

(1,476 ft), 48-channel streamer array is towed behind the source to record the reflected signals. Seismic 

signals are digitized at each hydrophone and recorded in SEG Y format in a top-side unit (Wood et al., 

2003; Wood, 2010). The DTAGS can also be configured with an aluminum landing plate, which 

transmits the acoustic energy directly into the seafloor. With this configuration, vertical bottom founded 

hydrophone arrays are used to receive reflections (Breland, 2010). 

Proximity of the acoustic source to the seafloor is an advantage of the DTAGS. The system has a 

limit of 1 km (0.6 mi) penetration in most marine sediments (Wood et al., 2003). It has been used very 

successfully to map out gas hydrates in the Gulf of Mexico (Wood et al., 2008), Canadian Pacific 

(Wood and Gettrust, 2000; Wood et al., 2002), and Blake Ridge (Wood and Gettrust, 2000). 

There is only one DTAGS in existence at this time. While it has imaged shallow sediments and gas 

hydrate environments extremely well, the current tool design could not replace a deep penetration airgun 

array for oil and gas exploration at this time; DTAGS was not designed for this purpose. However, there 

is no physical limitation to designing a resonant cavity source to simulate the frequency band of air guns. 

6.4. LOW FREQUENCY PASSIVE SEISMIC METHODS FOR EXPLORATION 

Low frequency passive seismic methods utilize microseisms, which are faint earth tremors caused by 

the natural sounds of the earth, to image the subsurface. A typical survey consists of highly sensitive 

receivers (usually broadband seismometers) placed in the area of interest to collect data over a period of 

time. Upon completion of the survey, the data are analyzed and filtered to remove all non-natural sounds, 

which is most efficiently completed using an automated process (Hanssen and Bussat, 2008). 

All of the current methods use one of following three sources of natural sounds: natural seismicity, 

ocean waves, or microseism surface waves. 

Natural seismicity uses the earth’s own movements as a source of energy. Two techniques have been 

developed to utilize this energy source. 

Daylight imaging (DLI) uses the local seismicity of an area to produce reflection seismic profiles, 

similar to those recorded in active seismic surveys (Claerbout, 1968). As in active reflection seismic 

operations, geophones are deployed; the target can be imaged using a regularly spaced 2D line geometry 

(Hohl and Mateeva, 2006; Draganov et al., 2009). The seismicity of the area, geologic complexity, and 

receiver sensitivity control the record length. The DLI can augment active seismic data, where it is 

difficult to collect data. 

Local earthquake tomography (LET) also uses local seismicity of a region to map on the reservoir 

scale (Kapotas et al., 2003). However, it is used to calculate the velocity structure of the subsurface in 3D 

by analyzing each earthquake on multiple receivers and generating ray paths instead of cross-correlating 
Existing Regulations, Protective Measures, and Mitigation C-31 

the recorded signals. This method requires a longer period of data collection than the other methods to 

produce results. 

Ocean waves are used as a sound source for the sea floor compliance technique. The method requires 

that ocean bottom seismometer (OBS) stations with highly-sensitive, broadband seismometers and 

differential or absolute pressure gauges be installed in water several hundred meters deep. In the right 

setting, a coarse one-dimensional (1D) S-wave velocity model of the subsurface down to the Moho can be 

generated using the measured water pressure and vertical movement of the seabed caused by large 

passing ocean waves (Crawford and Singh, 2008). 

Ambient-noise (surface-wave) tomography [AN(SW)T] uses low frequency (between 0.1 and 1 Hz) 

ambient noise records to estimate shear wave velocities and structural information about the earth. The 

ambient noise used consists mainly of microseism surface waves (Rayleigh and Love waves) (Bussat and 

Kugler, 2009). This technique requires the use of broadband seismometers to record the low frequency 

surface waves, which can penetrate to depths of several kilometers (Bensen et al., 2007, 2008). Because 

the marine environment produces abundant, high-energy surface waves, a few hours or days of 

acquisition can produce good quality data. The AN(SW)T can be used in areas where seismic data are 

difficult to collect or in environmentally sensitive areas. While this technology is new and still in need of 

further testing, the lateral resolution at several kilometer depths may reach a few hundred meters, and the 

resolution may be better than gravimetric or magnetic data, which is promising for oil and gas exploration 

(Bussat and Kugler, 2009). 

Surface-wave amplitudes (SWAs) is a 1D method that images the geological structure of the 

subsurface by analyzing passive acoustic data that have not been geophysically processed. The 

transformation of incoming micro-seismic surface waves, scattered at vertical discontinuities, into body 

waves may produce these data, but the process is not well understood (Gorbatikov et al., 2008). 

Low-frequency spectroscopy (LFS), also known as low frequency passive seismic (LFPS) or 

hydrocarbon microtremor analysis (HyMAS), tests for an indication of subsurface hydrocarbon 

accumulation using spectral signatures gathered from the ambient seismic wave field recorded by 

broadband seismometers. The cause of the spectral anomalies, often called direct hydrocarbon indicators, 

is presently unknown, but the following reasons have been proposed: standing wave resonance, selective 

attenuation, resonant amplification (Graf et al., 2007), and pore fluid oscillations (Frehner et al., 2006; 

Holzner et al., 2009). Energy anomalies in the frequency range between 1 and 6 Hz have been observed 

in known hydrocarbon areas including Mexico (Saenger et al., 2009), Abu Dhabi (Birkelo et al., 2010), 

Brazil, Austria (Graf et al., 2007), and southern Asia (West et al., 2010). However, this methodology is 

highly dependent on the ability to process out all anthropogenic noise and topography (Hanssen and 

Bussat, 2008). This method is still in the early stage of development and has not been confirmed in the 

field during all studies (Ali et al., 2007; Al-Faraj, 2007). 

The most successful use of low frequency passive micro-seismic data has been on land, where it is 

easier to isolate the extraneous noise from the natural signal. The technique is also promising in the 

marine environment. To ensure success of a marine survey: (1) it is imperative that the recording 

instruments are in proper contact with the substrate (the natural signal may not be accurately recorded in 

unconsolidated material) and (2) the increase in both anthropogenic and naturally produced noise in the 

marine environment is correctly filtered so that it does not mask the signal of interest. 

Passive seismic surveys cannot replace active seismic acquisition. However, passive acoustic data 

have the potential to enhance oil recovery at a better resolution than magnetic or gravimetric methods 

(Bussat and Kugler, 2009), especially in areas that are environmentally sensitive or where active seismic 

operations are difficult. 

6.5. LOW-IMPACT SEISMIC ARRAY (LISA) 

Nedwell (2010) describes the concept of a low impact seismic array (LISA) based on the use of 

inexpensive but powerful and rugged electromagnetic projectors to replace airgun arrays. The 

prospective benefit was that since the signal could be well controlled, both in frequency content and in the 

direction in which the sound propagated, the possibility existed of undertaking seismic surveys in 

environmentally sensitive areas with little or no collateral environmental impact. 

The LISA project embodies the idea of using a large array of small but powerful electromagnetic 

projectors to replace airgun arrays. Initial measurements were made on a small (n=4) array of existing 
C-32 Atlantic G&G Programmatic EIS 

electromagnetic transducers. It was found that a source level of about 142 dB re 1 μPa per volt @ 1 m 

was achieved, at a peak frequency of 25 Hz. The operating frequency could be reduced to below 10 Hz 

with reasonable modifications, allowing use of an array for seismic exploration. The results indicate that 

it would be possible to achieve an array source level of about 223 dB re 1 μPa @ 1 metre, which is 

adequate for seismic surveying. 

6.6. FIBER OPTIC RECEIVERS

Short of replacing seismic airguns, improvements in fiber optic sensing and telemetering could allow 

use of smaller airguns and airgun arrays in the future (Nash and Strudley, 2010). Fiber optic receivers are 

receivers that incorporate optical fibers to transmit the received acoustic signal as light. They are most 

frequently used in the petroleum industry for seismic permanent reservoir monitoring, a four-dimensional 

(4D) reservoir evaluation application. The optical receivers are permanently placed on the seafloor, 

ensuring consistency and repeatability of the 4D surveys, better signal to noise ratios, and quality of 

subsequently collected data. Fiber optic systems are not new. Fiber optical components have been used 

by the military for years in similar applications for antisubmarine warfare and area surveillance, and they 

have proven to be highly reliable. 

Fiber optic receivers are more sensitive than standard receivers, which allows for smaller airgun 

arrays to be used. While these receivers offer a benefit to the environment through a decrease in airgun 

noise, this technology is not presently available for towed-streamer surveys. 

Fiber optic receivers typically are used in areas with large-scale oil and gas production requiring 

4D monitoring. They would not be expected to be used in the Atlantic OCS during the time period of the 

Programmatic EIS because there are no active leases and only very limited exploration activities could 

occur between 2018-2020 if leasing is allowed (Chapter 3 of the Programmatic EIS). 

6.7. AIRGUN MODIFICATIONS TO LESSEN IMPACTS

In addition to alternative methods for seismic data collection, industry and the public sector have 

actively investigated the use of technology-based mitigation measures to lessen the impacts of airguns in 

the water. 

6.7.1. Airgun Silencers 

One such measure, an airgun silencer, which has acoustically absorptive foam rubber on metal plates 

mounted radially around the airgun, has demonstrated 0-6 dB reductions at frequencies above and 0-3 dB 

reductions below 700 Hz. This system has been tested only on low pressure airguns and is not a viable 

mitigation tool because it needs to be replaced after 100 shots (Spence et al., 2007). 

6.7.2. Bubble Curtains 

Bubble curtains generally consist of a rubber hose or metal pipe with holes to allow air passage and a 

connector hose attached to an air compressor. They have successfully been tested and used in 

conjunction with pile driving and at construction sites to frighten away fishes and decrease the noise level 

emitted into the surrounding water (Würsig et al., 2000; Sexton, 2007; Reyff, 2009). They have also been 

used as stand-alone units or with light and sound to deflect fishes away from dams or keep them out of 

specific areas (Pegg, 2005; Weiser, 2010). 

The use of bubbles as a mitigation for seismic noise has also been pursued. During an initial test of 

the concept, the sound source was flanked by two bubble screens; it demonstrated that bubble curtains 

were capable of attenuating seismic energy up to 28 dB at 80 Hz while stationary in a lake. This 

two-bubble curtain configuration was field tested from a moving vessel in Venezuela and Aruba where a 

12-dB suppression of low frequency sound and a decrease in the sound level of laterally projecting sound 

was documented (Sixma, 1996; Sixma and Stubbs, 1998). A different study in the Gulf of Mexico tested 

an “acoustic blanket” of bubbles as a method to suppress multiple reflections in the seismic data. The 

results of the acoustic blanket study determined that suppression of multiples was not practical using the 

current technology. However, the acoustic blanket measurably suppressed tube waves in boreholes and 

has the capability of blocking out thruster noises from a laying vessel during an ocean bottom cable 
Existing Regulations, Protective Measures, and Mitigation C-33 

survey, which would allow closer proximity of the shooting vessel and increase productivity (Ross et al., 

2004, 2005). 

A recent study “Methods to Reduce Lateral Noise Propagation from Seismic Exploration Vessels” 

was conducted by Stress Engineering Services Inc. under BOEM’s Technology Assessment & Research 

Program (Ayers et al., 2009, 2010). The first phase of the project was spent researching, developing 

concepts for noise reduction, and evaluating the following three concepts: (1) an air bubble curtain; 

(2) focusing arrays to create a narrower footprint; and (3) decreasing noise by redesigning airguns. The 

air bubble curtain was selected as the most promising alternative, which led to more refined studies the 

second year (Ayers et al., 2009). A rigorous 3D acoustic analysis of the preferred bubble curtain design, 

including shallow-water seafloor effects and sound attenuation within the bubble curtain, was conducted 

during the second phase of the study. Results of the model indicated that the bubble curtains performed 

poorly at reducing sound levels and are not a viable option for mitigation of lateral noise propagation 

during seismic operations from a moving vessel (Ayers et al., 2010). 

6.7.3. Reduction of Sound Source Levels 

Reduction of sound source levels would lower the peak pressures from an airgun array and reduce the 

size of the impact zone, further reducing the potential for acoustic impacts. Reduction of sound source 

levels has been evaluated on a limited number of occasions in the Gulf of Mexico. Lowering the peak 

pressure reduces not only the peak frequency but also the entire spectrum of frequencies emitted from a 

typical airgun array. In general, the spectrum extends from a low frequency of 10 Hz, reaches a peak 

frequency at about 50 Hz, then falls off. However, frequencies above 50 Hz are extremely important as 

they provide data on the finer details of a hydrocarbon deposit. 

G&G operators attempt to optimize their systems to use the broadest spectrum of energy, including 

higher frequencies. Reduction of source levels will reduce higher frequency output with the subsequent 

loss of these detailed data. The ability to interpret finer detail will be adversely affected should this 

mitigation measure be implemented. Therefore, G&G data acquired using lower sound source levels are 

considered unacceptable. Such data are extremely difficult to interpret. If data cannot be properly 

interpreted, there is also the possibility that areas would have to be re-surveyed, with the additional 

potential for impacts to marine mammals that might be present. 

7. REFERENCES CITED 

Al-Faraj, M. 2007. Workshop confirms promise of passive seismic for reservoir imaging and 

monitoring. First Break 25(7). 

Ali, M.Y., K.A. Berteussen, J. Small, and B. Barkat. 2007. A low frequency, passive seismic experiment 

over a carbonate reservoir in Abu Dhabi. First Break 25:71–73 

Askeland, B., H. Hobæk, and R. Mjelde. 2007. Marine seismics with a pulsed combustion source and 

Pseudo Noise codes. Marine Geophysical Research 28:109-117. Available at: https://bora.uib.no/

bitstream/1956/2215/4/mgr%20article%20askeland.pdf. Accessed September 28, 2011. 

Askeland, B., H. Hobæk, and R. Mjelde. 2008. Semiperiodic chirp sequences reduce autocorrelation side 

lobes of pulsed signals. Geophysics 73(3):Q19-Q27. 

Askeland, B., B.O. Ruud, H. Hobæk, and R. Mjelde. 2009. A seismic field test with a Low-level 

Acoustic Combustion Source and Pseudo-Noise codes. Journal of Applied Geophysics 67:66-73. 

Au, W.L. and M.C. Hastings. 2008. Hearing in marine animals, pp. 337-400. In: Principles of Marine 

Bioacoustics. Springer-Verlag, New York. 

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Existing Regulations, Protective Measures, and Mitigation C-39 

Attachment: Draft Seismic Airgun Survey Protocol 

Note: The following draft protocol is based on Joint BOEM-BSEE NTL 2012-G02 (Implementation 

of Seismic Survey Mitigation Measures and Protected Species Observer Program) (USDOI, BOEM and 

BSEE, 2012b) with the following key exceptions: 

 The protocol would apply to all seismic surveys in the AOI regardless of water depth. 

Joint NTL 2012-G02 does not apply to water depths less than 200 m (656 ft) in the 

Gulf of Mexico west of 88o W. 

 The radius of the exclusion zone would be based on the predicted range at which 

animals could be exposed to a received sound pressure level of 180 dB re 1 μPa, 

which is the current NMFS criterion for Level A harassment of cetaceans. The radius 

would be calculated for each survey but would not be less than 500 m (1,640 ft). In 

contrast, Joint NTL 2012-G02 specifies a single, fixed radius of 500 m (1,640 ft). 

 Shutdown of the airgun array would be required any time a marine mammal or sea 

turtle is observed within the exclusion zone, whether due to the animal’s movement, 

the vessel’s movement, or because the animal surfaced inside the exclusion zone. 

There would be an exception for dolphins approaching the vessel or towed equipment 

at a speed and vector that indicates voluntary approach to bow-ride or chase towed 

equipment. In contrast, Joint NTL 2012-G02 requires the exclusion zone to be clear 

of all marine mammals and sea turtles for startup, but shutdown is required only for 

whales entering the exclusion zone. 

Background 

The use of an airgun or airgun arrays while conducting seismic operations may have an impact on 

marine wildlife, including marine mammals and sea turtles. Some marine mammals, such as the North 

Atlantic right whale (Eubalaena glacialis), blue whale (Balaenoptera musculus), fin whale (Balaenoptera 

physalus), sei whale (Balaenoptera borealis), humpback whale (Megaptera novaeangliae), sperm whale 

(Physeter macrocephalus), and Florida manatee (Trichechus manatus latirostris), that inhabit the AOI are 

protected under the ESA, and all marine mammals are protected under the MMPA. All five sea turtle 

species inhabiting the AOI are protected under the ESA. They are the loggerhead turtle (Caretta caretta), 

green turtle (Chelonia mydas), hawksbill turtle (Eretmochelys imbricata), Kemp’s ridley turtle 

(Lepidochelys kempii), and leatherback turtle (Dermochelys coriacea). 

In order to protect marine mammals and sea turtles during seismic operations, the NMFS requires 

seismic operators to use ramp-up and visual observation procedures when conducting seismic surveys. 

Procedures for ramp-up, protected species observer training, visual monitoring, and reporting are 

described in detail in this protocol. These mitigation measures apply to all seismic survey operations 

conducted regardless of water depth. Performance of these mitigation measures is also a condition of the 

approval of applications for geophysical permits. Permittees must demonstrate compliance with these 

mitigation measures by submitting to BOEM certain reports detailed in this protocol. The measures 

contained herein would apply to all on-lease surveys conducted under 30 CFR 550 and all off-lease 

surveys conducted under 30 CFR 551 in the AOI. In addition, the measures would apply to any deep 

penetration seismic surveys conducted to evaluate formation suitability for carbon sequestration in the 

renewable energy program. 

Definitions 

Terms used in this protocol have the following meanings: 

1. Airgun means a device that releases compressed air into the water column, creating 

an acoustical energy pulse with the purpose of penetrating the seafloor. 

2. Ramp-up means the gradual increase in emitted sound levels from an airgun array by 

systematically turning on the full complement of an array’s airguns over a period of 

time. 
C-40 Atlantic G&G Programmatic EIS

3. Visual monitoring means the use of trained protected species observers to scan the 

ocean surface visually for the presence of marine mammals and sea turtles. These 

observers must have successfully completed a visual observer training program as 

described below. The area to be scanned visually includes, but is not limited to, the 

exclusion zone. Visual monitoring of an exclusion zone and adjacent waters is 

intended to establish and, when visual conditions allow, maintain a zone around the 

sound source and seismic vessel that is clear of marine mammals and sea turtles, 

thereby reducing or eliminating the potential for injury. 

4. Exclusion zone means the area at and below the sea surface within a radius to be 

determined by calculating the maximum range at which animals could be exposed to 

a received sound pressure level of 180 dB re 1 μPa, which is the current NMFS 

criterion for Level A harassment of cetaceans. The distance is calculated from the 

center of an airgun array. Each survey vessel must maintain its own unique exclusion 

zone. The radius of the exclusion zone must be calculated independently for each 

survey based on the configuration of the airgun array and the ambient acoustic 

environment, but must not be less than 500 m (1,640 ft). 

5. Dolphins mean all marine mammal species in the family Delphinidae. This includes, 

among others, killer whales, pilot whales, and all of the “dolphin” species. 

Ramp-Up Procedures 

The intent of ramp-up is to warn marine mammals and sea turtles of pending seismic operations and 

to allow sufficient time for those animals to leave the immediate vicinity. Under normal conditions, 

animals sensitive to these activities are expected to move out of the area. For all seismic surveys, 

including airgun testing, use the ramp-up procedures described below to allow marine mammals and sea 

turtles to depart the exclusion zone before seismic surveying begins. 

Measures to conduct ramp-up procedures during all seismic survey operations, including airgun 

testing, are as follows: 

1. Visually monitor the exclusion zone and adjacent waters for the absence of marine 

mammals and sea turtles for at least 30 min before initiating ramp-up procedures. If 

none are detected, you may initiate ramp-up procedures. Do not initiate ramp-up 

procedures at night or when you cannot visually monitor the exclusion zone for 

marine mammals and sea turtles if your minimum source level drops below 160 dB 

re 1 μPa-m (rms) (see measure 5). 

2. Initiate ramp-up procedures by firing a single airgun. The preferred airgun to begin 

with should be the smallest airgun, in terms of energy output (dB) and volume (in3

). 

3. Continue ramp-up by gradually activating additional airguns over a period of at least 

20 min, but no longer than 40 min, until the desired operating level of the airgun 

array is obtained. 

4. Immediately shut down all airguns, ceasing seismic operations at any time a marine 

mammal or sea turtle is detected entering or within the exclusion zone. However, 

shutdown would not be required for dolphins approaching the vessel or towed 

equipment at a speed and vector that indicates voluntary approach to bow-ride or 

chase towed equipment. After a shutdown, you may recommence seismic operations 

and ramp-up of airguns only when the exclusion zone has been visually inspected for 

at least 30 min to ensure the absence of marine mammals and sea turtles. 

5. You may reduce the source level of the airgun array, using the same shot interval as 

the seismic survey, to maintain a minimum source level of 160 dB re 1 μPa-m (rms) 

for the duration of certain activities. By maintaining the minimum source level, you 

will not be required to conduct the 30-min visual clearance of the exclusion zone 

before ramping back up to full output. Activities that are appropriate for maintaining 

the minimum source level are (1) all turns between transect lines, when a survey 

using the full array is being conducted immediately prior to the turn and will be 

resumed immediately after the turn; and (2) unscheduled, unavoidable maintenance 

of the airgun array that requires the interruption of a survey to shut down the array. 
Existing Regulations, Protective Measures, and Mitigation C-41 

The survey should be resumed immediately after the repairs are completed. There 

may be other occasions when this practice is appropriate, but use of the minimum 

source level to avoid the 30-min visual clearance of the exclusion zone is only for 

events that occur during a survey using the full power array. The minimum sound 

source level is not to be used to allow a later ramp-up after dark or in conditions 

when ramp-up would not otherwise be allowed. 

Protected Species Observer Program 

Visual Observers 

Visual observers who have completed a protected species observer training program as described 

below are required on all seismic vessels conducting operations in the AOI. at least two protected species 

visual observers will be required on watch aboard seismic vessels at all times during daylight hours (dawn 

to dusk) when seismic operations are being conducted, unless conditions (fog, rain, darkness) make sea 

surface observations impossible. If conditions deteriorate during daylight hours such that the sea surface 

observations are halted, visual observations must resume as soon as conditions permit. Operators may 

engage trained third party observers, utilize crew members after training as observers, or use a 

combination of both third party and crew observers. During these observations, the following guidelines 

shall be followed: (1) other than brief alerts to bridge personnel of maritime hazards, no additional duties 

may be assigned to the observer during his/her visual observation watch (if conditions warrant more 

vigilant look-outs when navigating around or near maritime hazards, additional personnel must be used to 

ensure that watching for protected species remains the primary focus of the on-watch observers); (2) no 

observer will be allowed more than 4 consecutive hours on watch as a visual observer; (3) a “break” time 

of no less than 2 hr must be allowed before an observer begins another visual monitoring watch rotation 

(break time means no assigned observational duties); and (4) no person (crew or third party) on watch as a 

visual observer will be assigned a combined watch schedule of more than 12 hr in a 24-hr period. Due to 

the concentration and diligence required during visual observation watches, operators who choose to use 

trained crew members in these positions may select only those crew members who demonstrate 

willingness as well as ability to perform these duties. 

Training 

All visual observers must have completed a protected species observer training course. The BOEM 

will not sanction particular trainers or training programs. However, basic training criteria have been 

established and must be adhered to by any entity that offers observer training. Operators may utilize 

observers trained by third parties, may send crew for training conducted by third parties, or may develop 

their own training program. All training programs offering to fulfill the observer training requirement 

must (1) furnish to BOEM a course information packet that includes the name and qualifications 

(i.e., experience, training completed, or educational background) of the instructor(s), the course outline or 

syllabus, and course reference material; (2) furnish each trainee with a document stating successful 

completion of the course; and (3) provide BOEM with names, affiliations, and dates of course completion 

of trainees. 

The training course must include the following elements: 

I. Brief overview of the MMPA and the ESA as they relate to seismic acquisition and 

protection of marine mammals and sea turtles in the Atlantic Ocean. 

II. Brief overview of seismic acquisition operations. 

III. Overview of seismic mitigation measures and the protected species observer program. 

IV. Discussion of the role and responsibilities of the protected species observer, including 

a) Legal requirements (why you are here and what you do); 

b) Professional behavior (code of conduct); 

c) Integrity; 

d) Authority of protected species observer to call for shutdown of seismic acquisition 

operations; 
C-42 Atlantic G&G Programmatic EIS

e) Assigned duties; 

1) What can be asked of the observer; 

2) What cannot be asked of the observer; and 

f) Reporting of violations and coercion; 

V. Identification of Atlantic marine mammals and sea turtles. 

VI. Cues and search methods for locating marine mammals and sea turtles. 

VII. Data collection and reporting requirements: 

a) Forms and reports to BOEM via email on the 1st and 15th of each month; and 

b) Marine mammal or sea turtle in exclusion zone/shutdown report within 24 hr. 

Visual Monitoring Methods 

The observers on duty will look for marine mammals and sea turtles using the naked eye and handheld binoculars provided by the seismic vessel operator. The observers will stand watch in a suitable 

location that will not interfere with navigation or operation of the vessel and that affords the observers an 

optimal view of the sea surface. The observers will provide 360o coverage surrounding the seismic vessel 

and adjust their positions appropriately to ensure adequate coverage of the entire area. These 

observations must be consistent, diligent, and free of distractions for the duration of the watch. 

Visual monitoring will begin no less than 30 min prior to the beginning of ramp-up and continue until 

seismic operations cease or sighting conditions do not allow observation of the sea surface (e.g., fog, rain, 

darkness). If a marine mammal or sea turtle is observed, the observer should note and monitor the 

position (including latitude/longitude of the vessel and relative bearing and estimated distance to the 

animal) until the animal dives or moves out of visual range of the observer. Make sure you continue to 

observe for additional animals that may surface in the area, as often there are numerous animals that may 

surface at varying time intervals. At any time a marine mammal or sea turtle is observed within the 

exclusion zone, whether due to the animal’s movement, the vessel’s movement, or because the animal 

surfaced inside the exclusion zone, the observer will call for the immediate shutdown of the seismic 

operation, including airgun firing (the vessel may continue on its course but all airgun discharges must 

cease). However, shutdown would not be required for dolphins approaching the vessel or towed 

equipment at a speed and vector that indicates voluntary approach to bow-ride or chase towed equipment. 

The vessel operator must comply immediately with such a call by an on-watch visual observer. Any 

disagreement or discussion should occur only after shutdown. After a shutdown, when no marine 

mammals or sea turtles are sighted for at least a 30-min period, ramp-up of the source array may begin. 

Ramp-up cannot begin unless conditions allow the sea surface to be visually inspected for marine 

mammals and sea turtles for 30 min prior to commencement of ramp-up (unless the method described in 

the section entitled “Experimental Passive Acoustic Monitoring” is used). Thus, ramp-up cannot begin 

after dark or in conditions that prohibit visual inspection (fog, rain, etc.) of the exclusion zone. Any 

shutdown due to a marine mammal or sea turtle sighting within the exclusion zone must be followed by a 

30-min all-clear period and then a standard, full ramp-up. Any shutdown for other reasons, including, but 

not limited to, mechanical or electronic failure, resulting in the cessation of the sound source for a period 

greater than 20 min, must also be followed by full ramp-up procedures. In recognition of occasional, 

short periods of the cessation of airgun firing for a variety of reasons, periods of airgun silence not 

exceeding 20 min in duration will not require ramp-up for the resumption of seismic operations if 

(1) visual surveys are continued diligently throughout the silent period (requiring daylight and reasonable 

sighting conditions), and (2) no marine mammals or sea turtles are observed in the exclusion zone. If 

marine mammals or sea turtles are observed in the exclusion zone during the short silent period, 

resumption of seismic survey operations must be preceded by ramp-up. 

Reporting 

The importance of accurate and complete reporting of the results of the mitigation measures cannot be 

overstated. Only through diligent and careful reporting can BOEM, and subsequently the NMFS, 

determine the need for and effectiveness of mitigation measures. Information on observer effort and 

seismic operations is as important as animal sighting and behavior data. In order to accommodate various 

vessels’ bridge practices and preferences, vessel operators and observers may design data reporting forms 

in whatever format they deem convenient and appropriate. Alternatively, observers or vessel operators 
Existing Regulations, Protective Measures, and Mitigation C-43 

may adopt the United Kingdom’s Joint Nature Conservation Committee forms (available at their website, 

www.jncc.gov.uk). At a minimum, the following items should be recorded and included in reports to 

BOEM: 

Observer Effort Report: Prepared for each day during which seismic acquisition operations are 

conducted. Furnish an observer effort report to BOEM on the 1st and the 15th of each month that 

includes 

 vessel name; 

 observers’ names and affiliations; 

 survey type (e.g., site, 3D, 4D); 

 BOEM Permit Number (for “off-lease seismic surveys”) or OCS Lease Number 

(for “on-lease seismic surveys”); 

 date; 

 time and latitude/longitude when daily visual survey began; 

 time and latitude/longitude when daily visual survey ended; and 

 average environmental conditions while on visual survey, including 

 wind speed and direction; 

 sea state (glassy, slight, choppy, rough, or Beaufort scale); 

 swell (low, medium, high, or swell height in meters); and 

 overall visibility (poor, moderate, good). 

Survey Report: Prepared for each day during which seismic acquisition operations are conducted and 

the airguns are being discharged. Furnish a survey report to BOEM on the 1st and the 15th of each month 

during which operations are being conducted that includes 

 vessel name; 

 survey type (e.g., site, 3D, 4D); 

 BOEM Permit Number (for “off-lease seismic surveys”) or OCS Lease Number 

(for “on-lease seismic surveys”); 

 date; 

 time pre-ramp-up survey begins; 

 what marine mammals and sea turtles were seen during pre-ramp-up survey; 

 time ramp-up begins; 

 were marine mammals seen during ramp-up; 

 time airgun array is operating at the desired intensity; 

 what marine mammals and sea turtles were seen during survey; 

 if marine mammals were seen, was any action taken (i.e., survey delayed, guns shut 

down); 

 reason that marine mammals might not have been seen (e.g., swell, glare, fog); and 

 time airgun array stops firing. 

Sighting Report: Prepared for each sighting of a marine mammal or sea turtle made during seismic 

acquisition operations. Furnish a sighting report to BOEM on the 1st and the 15th of each month during 

which operations are being conducted that includes 

 vessel name; 

 survey type (e.g., site, 3D, 4D); 

 BOEM Permit Number (for “off-lease seismic surveys”) or OCS Lease Number 

(for “on-lease seismic surveys”); 

 date; 

 time; 

 watch status (Were you on watch or was this sighting made opportunistically by you 

or someone else?); 
C-44 Atlantic G&G Programmatic EIS

 observer or person who made the sighting; 

 latitude/longitude of vessel; 

 bearing of vessel; 

 bearing and estimated range to animal(s) at first sighting; 

 water depth (meters); 

 species (or identification to lowest possible taxonomic level); 

 certainty of identification (sure, most likely, best guess); 

 total number of animals; 

 number of juveniles; 

 description (as many distinguishing features as possible of each individual seen, 

including length, shape, color and pattern, scars or marks, shape and size of dorsal 

fin, shape of head, and blow characteristics); 

 direction of animal’s travel – compass direction; 

 direction of animal’s travel – related to the vessel (drawing preferably); 

 behavior (as explicit and detailed as possible; note any observed changes in 

behavior); 

 activity of vessel; 

 airguns firing (yes or no); and 

 closest distance (meters) to animals from center of airgun or airgun array (whether 

firing or not). 

Note: If this sighting was of a marine mammal or sea turtle within the exclusion zone that 

resulted in a shutdown of the airguns, include in the sighting report the observed behavior of the 

animal(s) before shutdown, the observed behavior following shutdown (specifically noting any change in 

behavior), and the length of time between shutdown and subsequent ramp-up to resume the seismic 

survey (note if seismic survey was not resumed as soon as possible following shutdown). Send this report 

to BOEM within 24 hr of the shutdown. These sightings should also be included in the first regular 

semi-monthly report following the incident. 

Additional information, important points, and comments are encouraged. All reports will be 

submitted to BOEM on the 1st and the 15th of each month (with one exception noted above). Forms 

should be scanned (or data typed) and sent via email to BOEM.

Please note that these marine mammal and sea turtle reports are in addition to any reports required as 

a condition of the geophysical permit. 

Borehole Seismic Surveys 

Borehole seismic surveys differ from surface seismic surveys in a number of ways, including the use 

of much smaller airgun arrays, having an average survey time of 12-24 hr, utilizing a sound source that is 

not usually moving at 7.4-9.3 km/hr (4-5 kn), and requiring the capability of moving the receiver in the 

borehole between shots. Due to these differences, the following altered mitigations apply only to 

borehole seismic surveys: 

 During daylight hours, when visual observations of the exclusion zone are being 

performed as required in this protocol, borehole seismic operations will not be 

required to ramp-up for shutdowns of 30 min or less in duration, as long as no marine 

mammals or sea turtles are observed in the exclusion zone during the shutdown. If a 

marine mammal or sea turtle is sighted in the exclusion zone, ramp-up is required and 

may begin only after visual surveys confirm that the exclusion zone has been clear 

for 30 min. 

 During nighttime or when conditions prohibit visual observation of the exclusion 

zone, ramp-up will not be required for shutdowns of 20 min or less in duration. For 

borehole seismic surveys that utilize passive acoustics during nighttime and periods 

of poor visibility, ramp-up is not required for shutdowns of 30 min or less. 
Existing Regulations, Protective Measures, and Mitigation C-45 

 Nighttime or poor visibility ramp-up is allowed only when passive acoustics are used 

to ensure that no marine mammals are present in the exclusion zone (as for all other 

seismic surveys). Operators are strongly encouraged to acquire the survey in daylight 

hours when possible. 

 Protected species observers must be used during daylight hours, as required in this 

protocol, and may be stationed either on the source boat or on the associated drilling 

rig or platform if a clear view of the sea surface in the exclusion zone and adjacent 

waters is available. 

 All other mitigations and provisions for seismic surveys as set forth in this protocol 

will apply to borehole seismic surveys. 

 Reports should reference OCS Lease Number, Area/Block and Borehole Number. 

Experimental Passive Acoustic Monitoring 

Whales are very vocal marine mammals, and periods of silence are usually short and most often occur 

when these animals are at the surface and may be detected using visual observers. However, whales are 

at the greatest risk of potential injury from seismic airguns when they are submerged and under the airgun 

array. Passive acoustic monitoring appears to be very effective at detecting submerged and diving sperm 

whales, and some other marine mammal species, when they are not detectable by visual observation. The 

BOEM strongly encourages operators to participate in an experimental program by including passive 

acoustic monitoring as part of the protected species observer program. Inclusion of passive acoustic 

monitoring does not relieve an operator of any of the mitigations (including visual observations) in this 

protocol with the following exception: Monitoring for whales with a passive acoustic array by an 

observer proficient in its use will allow ramp-up and the subsequent start of a seismic survey during times 

of reduced visibility (darkness, fog, rain, etc.) when such ramp-up otherwise would not be permitted using 

only visual observers. If passive acoustic monitoring is used, an assessment must be included of the 

usefulness, effectiveness, and problems encountered with the use of that method of marine mammal 

detection in the reports described in this protocol. A description of the passive acoustic system, the 

software used, and the monitoring plan should also be reported to BOEM at the beginning of its use. 

APPENDIX D 

 

ACOUSTIC MODELING REPORT

Acoustic Modeling Report D-iii

TABLE OF CONTENTS 

Page 

1. INTRODUCTION ............................................................................................................................D-1

2. BASICS OF UNDERWATER ACOUSTICS...................................................................................D-1

2.1. Acoustic Metrics ......................................................................................................................D-1

2.2. Major Factors Affecting Underwater Sound Propagation........................................................D-2

2.2.1. Geometric Spreading....................................................................................................D-2

2.2.2. Absorption .................................................................................................................D-3

2.2.3. Refraction .................................................................................................................D-3

2.2.4. Scattering .................................................................................................................D-5

2.2.5. Bathymetry .................................................................................................................D-5

2.2.6. Source Depth................................................................................................................D-5

2.2.7. Bottom Loss .................................................................................................................D-6

2.3. Acoustic Impact Criteria ..........................................................................................................D-6

2.3.1. M-Weighting ................................................................................................................D-6

2.3.2. Consideration of the Minimum Integration Time ........................................................D-8

2.3.3. National Marine Fisheries Service Criteria..................................................................D-8

2.3.4. Southall Criteria ...........................................................................................................D-9

3. ACOUSTIC SOURCES..................................................................................................................D-10

3.1. Airgun Sources.......................................................................................................................D-10

3.1.1. Seismic Survey Overview ..........................................................................................D-10

3.1.2. Airgun Operating Principles.......................................................................................D-11

3.1.3. Airgun Array Source Levels ......................................................................................D-12

3.1.4. Airgun Array Source Model.......................................................................................D-12

3.1.5. Large Airgun Array....................................................................................................D-13

3.1.6. Small Airgun Array....................................................................................................D-16

3.2. Electromechanical Sources ....................................................................................................D-17

3.2.1. Beam Pattern Calculation...........................................................................................D-17

3.2.2. Beam Pattern of a Circular Transducer ......................................................................D-18

3.2.3. Beam Pattern of a Rectangular Transducer................................................................D-19

3.2.4. Beam Pattern of a Multibeam System........................................................................D-20

3.2.5. Boomer ...............................................................................................................D-21

3.2.6. Side-Scan Sonar .........................................................................................................D-25

3.2.7. Chirp Subbottom Profiler ...........................................................................................D-27

3.2.8. Multibeam Depth Sounder .........................................................................................D-31

4. MODELING METHODOLOGY ...................................................................................................D-32

4.1. Sound Propagation Model: MONM......................................................................................D-33

4.1.1. Low-Frequency – MONM-RAM ...............................................................................D-33

4.1.2. Mid- and High-Frequency – MONM-BELLHOP......................................................D-34

4.1.3. Estimating 90 Percent RMS SPL from SEL for Airgun Array Sources.....................D-34

4.2. Modeling Procedure...............................................................................................................D-35

4.2.1. Area of Interest and Proposed Activities....................................................................D-35

4.2.2. Model Profiles............................................................................................................D-38

4.2.3. Model Receiver Depths..............................................................................................D-39

4.2.4. Model Radial Step Size..............................................................................................D-40
D-iv Atlantic G&G Programmatic EIS 

4.3. Bathymetry and Acoustic Parameters ....................................................................................D-40

4.3.1. Bathymetry ...............................................................................................................D-40

4.3.2. Geoacoustic Properties...............................................................................................D-40

4.3.3. Sound Speed Profiles .................................................................................................D-42

4.4. Modeling Scenarios ...............................................................................................................D-45

4.5. Classification of Acoustic Environments...............................................................................D-45

4.5.1. Shallow Continental Shelf..........................................................................................D-45

4.5.2. Continental Shelf........................................................................................................D-47

4.5.3. Continental Slope .......................................................................................................D-48

4.5.4. Deep Ocean ...............................................................................................................D-49

5. MODEL RESULTS ........................................................................................................................D-50

6. REFERENCES CITED...................................................................................................................D-54

ATTACHMENT A: SOUND MAPS ....................................................................................................D-58

ATTACHMENT B: PREDICTED RANGES TO SPECIFIED THRESHOLD LEVELS....................D-82
Acoustic Modeling Report D-v

LIST OF FIGURES 

Page 

Figure D-1. Sample Plot of Absorption Loss Versus Frequency ...........................................................D-3

Figure D-2. Generic Sound Speed Profile with Some Common Features Defined................................D-4

Figure D-3. Example of an Acoustic Field from an Airgun Array Source with Convergence 

Zones...................................................................................................................................D-5

Figure D-4. Standard M-Weighting Curves for Low-, Mid-, and High-Frequency Cetaceans and 

Pinnipeds Underwater. ........................................................................................................D-7

Figure D-5. Overpressure Signature for a Single Airgun, Showing the Primary Peak and the 

Bubble Pulse. ....................................................................................................................D-11

Figure D-6. Layout of the 5,400 in3 Seismic Array..............................................................................D-14

Figure D-7. Predicted Overpressure Signature and Power Spectrum for the 5,400-in3 Airgun 

Array in the Broadside and Endfire Directions.................................................................D-14

Figure D-8. Azimuthal Directivity Pattern of SLs for the 5,400-in3 Array at 6.5-m Depth, Shown 

in Third-Octave Bands by Center Frequency....................................................................D-15

Figure D-9. Maximum Directional SLs in Each Third-Octave Band for the 5,400-in3 Airgun 

Array. ................................................................................................................................D-16

Figure D-10. Maximum Directional SLs in Each Third-Octave Band for the 90-in3 Airgun Array. .....D-17

Figure D-11. Typical 3D Beam Pattern for a Circular Transducer.........................................................D-18

Figure D-12. 2D Polar Representation of a Beam Pattern Obtained by In Situ Measurement 

(vertical slice) of a Transducer Used by Kongsberg.........................................................D-18

Figure D-13. Calculated Beam Pattern for a Circular Transducer with a Beam Width of 20°...............D-19

Figure D-14. Calculated Beam Pattern for a Rectangular Transducer with a 4°×10° Beam Width.......D-20

Figure D-15. Calculated Beam Pattern for Two Rectangular Transducers Engaged 

Simultaneously, with Individual Beam Widths of 1.5°×50°, and a Declination 

Angle of 25°......................................................................................................................D-20

Figure D-16. Surface Towed Boomer Source. .......................................................................................D-21

Figure D-17. Source Pulse of the AA201 Boomer at 100 J Energy Output. ..........................................D-21

Figure D-18. Example of a Representative Boomer Plate System. ........................................................D-22

Figure D-19. Calculated Beam Pattern for the Representative Boomer at (a) 1.25 and 

(b) 16.0 kHz ......................................................................................................................D-24

Figure D-20. Calculated Beam Pattern Vertical Slice for the Representative Boomer at (a) 1.25 

and (b) 16.0 kHz; Across-Track Direction........................................................................D-24

Figure D-21. Example of a Representative Side-Scan Sonar System ....................................................D-25

Figure D-22. Calculated Beam Pattern for the Representative Side-Scan Sonar at 100 kHz, 

Operating in High-Speed Mode ........................................................................................D-26

Figure D-23. Calculated Beam Pattern Vertical Slice for the Representative Side-Scan Sonar at 

100 kHz Operating in High-Speed Mode; Along- and Across-Track Directions. ............D-26

Figure D-24. Calculated Beam Pattern for a Representative Chirp Subbottom Profiler at 3.5 kHz.......D-28

Figure D-25. Calculated Beam Pattern for a Representative Chirp Subbottom Profiler at 12 kHz........D-28
D-vi Atlantic G&G Programmatic EIS 

Figure D-26. Calculated Beam Pattern for a Representative Chirp Subbottom Profiler at 200 kHz......D-29

Figure D-27. Calculated Beam Pattern Vertical Slice for a Representative Chirp Subbottom 

Profiler Operating at 3.5 kHz............................................................................................D-29

Figure D-28. Calculated Beam Pattern Vertical Slice for a Representative Chirp Subbottom 

Profiler Operating at 12 kHz; Along- and Across-Track Directions.................................D-30

Figure D-29. Calculated Beam Pattern Vertical Slice for a Representative Chirp Subbottom 

Profiler Operating at 200 kHz...........................................................................................D-30

Figure D-30. Calculated Beam Pattern for the Representative Multibeam Depth Sounder at 

240 kHz.............................................................................................................................D-31

Figure D-31. Calculated Beam Pattern Vertical Slice for the Representative Multibeam Depth 

Sounder at 240 kHz; Along- and Across-Track Directions. .............................................D-32

Figure D-32. SPL–SEL Conversion Functions for Different Water Depths. .........................................D-35

Figure D-33. Area of Interest with the Locations of the Modeling Sites. ..............................................D-36

Figure D-34. Sound Velocity Profiles for Winter Season Used in This Modeling Study: Fully 

Extended to the Maximum Depth (left) and Zoomed-in Upper Portion (right)................D-43

Figure D-35. Sound Velocity Profiles for Spring Season Used in This Modeling Study: Fully 

Extended to the Maximum Depth and Zoomed-in Upper Portion....................................D-43

Figure D-36. Sound Velocity Profiles for Summer Seasons Used in This Modeling Study: Fully 

Extended to the Maximum Depth and Zoomed-in Upper Portion....................................D-44

Figure D-37. Sound Velocity Profiles for Fall Season Used in This Modeling Study: Fully 

Extended to the Maximum Depth and Zoomed-in Upper Portion....................................D-44

Figure D-38. Frequency Versus Distance Plot Based on Modeled Data for Scenario 22 (SVP 03) 

(water depth at the source is 30 m). ..................................................................................D-47

Figure D-39. Frequency Versus Distance Plot Based on Modeled Data for Scenario 23 (SVP 03) 

(water depth at the source is 100 m). ................................................................................D-47

Figure D-40. Frequency Versus Distance Plot Based on Modeled Data for Scenario 14 (SVP 08) 

(water depth at the source is 250 m). ................................................................................D-48

Figure D-41. Frequency Versus Distance Plot Based on Modeled Data for Scenario 3 (SVP 01) 

(water depth at the source is 880 m). ................................................................................D-49

Figure D-42. Frequency Versus Distance Plot Based on Modeled Data for Scenario 1 (SVP 01) 

(water depth at the source is 5,390 m). .............................................................................D-49
Acoustic Modeling Report D-vii 

LIST OF TABLES 

Page 

Table D-1. Low-Frequency (flo) and High-Frequency (fhi) Cutoff Parameters for Standard 

Marine Mammal M-Weighting Curves...............................................................................D-8

Table D-2. Southall Criteria for Injury..................................................................................................D-9

Table D-3. List of Acoustic Source Types Modeled in This Study Indicating Representative 

Equipment Types, Operating Frequencies, and Survey Application ................................D-10

Table D-4. 5,400-in3 Airgun Array Pressure Characteristics from the AASM Model at 6.5-m 

Depth.................................................................................................................................D-15

Table D-5. 90-in3 Airgun Array Pressure Characteristics from the AASM Model at 6.5 m 

Depth.................................................................................................................................D-16

Table D-6. Representative Boomer Specifications .............................................................................D-23

Table D-7. Estimated Source Levels (rms SPL) and Beam Width from the Representative 

Boomer Distributed into Twenty 1/3-Octave Bands.........................................................D-23

Table D-8. Representative Side-Scan Sonar Parameters for the High-Speed and 

High-Definition Operating Modes ....................................................................................D-25

Table D-9. Variable Angular Steps of the Modeling Radials in Different Sectors .............................D-27

Table D-10. Representative Chirp Subbottom Profiler Specifications..................................................D-28

Table D-11. Representative Multibeam Depth Sounder Specifications................................................D-31

Table D-12. Variable Angular Steps of the Modeling Radials in Different Sectors .............................D-32

Table D-13. List of Proposed G&G Activities and Sources .................................................................D-37

Table D-14. Modeling Site Information................................................................................................D-38

Table D-15. Modeling Profile Information for Airgun Array Sources at Different Sites .....................D-39

Table D-16. Modeling Profile Information for Electromechanical Sources Except the Boomer..........D-39

Table D-17. Geoacoustic Model for the Clay Sediments......................................................................D-41

Table D-18. Geoacoustic Model for the Sand Sediments .....................................................................D-41

Table D-19. List of Sound Speed Profiles Used in This Study .............................................................D-42

Table D-20. List of Modeling Scenarios...............................................................................................D-46

Table D-21. Summary of the Predicted Threshold Radii (in meters) for the 180 and 160 dB SPL 

(rms) for Airgun Array Sources ........................................................................................D-51

Table D-22. Summary of the Predicted Threshold Radii (in meters) for 180 and 160 dB SPL 

(rms) for Electromechanical Sources................................................................................D-51

Table D-23. Adjustment of the 180-dB and 160-dB Threshold Radii Based on the Difference 

between the Pulse Length of the Electromechanical Sources and the Minimum 

Integration Time of the Mammalian Hearing Apparatus (100 ms)...................................D-52

Table D-24. Safety Zone Radii (in Meters) Based on Southall et al. (2007) Injury Criterion for 

the Maximum Peak Pressure.............................................................................................D-53

Table D-25. Safety Zone Radii (in Meters) for the Airgun Array Sources Based on Southall et al. 

(2007) Injury Criterion for the Sound Exposure Level (198 dB re 1 μPa2

 s) ..................D-53
D-viii Atlantic G&G Programmatic EIS 

Table D-26. Safety Zone Radii (in meters) Based on Southall et al. (2007) Injury Criterion Based 

on the Sound Exposure Level (198 dB re 1 μPa2

·s)..........................................................D-54
Acoustic Modeling Report D-ix 

LIST OF ACRONYMS AND ABBREVIATIONS 

2D two-dimensional 

3D three-dimensional 

AASM Airgun Array Source Model 

AIM Acoustic Integration Model©

ANSI American National Standard 

Institute 

BOEM Bureau of Ocean Energy 

Management 

C Celsius 

cm centimeter 

CW continuous wave 

dB decibel 

G&G geological and geophysical 

GDEM Generalized Digital Environmental 

Model 

GI generator-injector 

HRG high-resolution geophysical 

Hz hertz 

in inch 

J joule 

kHz kilohertz 

kJ kilojoule 

km kilometer 

kV kilovolt 

kW kilowatt 

m meter 

MAI Marine Acoustics, Inc. 

mbsf meters below seafloor 

MMPA Marine Mammal Protection Act 

MONM Marine Operations Noise Model 

MOODS Master Oceanographic 

Observational Data Set 

NMFS National Marine Fisheries Service 

nmi nautical mile 

OCS Outer Continental Shelf 

ODP Ocean Drilling Program 

PE parabolic equation 

Programmatic EIS Programmatic 

Environmental Impact Statement 

ppt parts per trillion 

RAM Range-dependent Acoustic Model 

RL received level 

rms root-mean-square 

s second 

SEL sound exposure level 

SL source level 

SPL sound pressure level 

TL transmission level 

USGS U.S. Geological Survey 

VSP vertical seismic profiling

Acoustic Modeling Report D-1 

1. INTRODUCTION 

This report provides technical information in support of the Draft Programmatic Environmental 

Impact Statement (Programmatic EIS) prepared by the Bureau of Ocean Energy Management (BOEM) 

concerning the potential environmental effects of geological and geophysical (G&G) exploration 

activities on the Mid- and South Atlantic Outer Continental Shelf (OCS). Specifically, this document 

describes the procedures used to estimate the sound fields that would be generated by airgun arrays and 

electromechanical sources during said activities. Some background information on acoustic metrics and 

on the principal factors that affect sound propagation in the water is also provided as a preamble. 

The proposed G&G exploration activities encompass a wide range of marine geotechnical studies 

using acoustic sources including seismic surveying (high-resolution, 2D, 3D, and vertical seismic 

profiling [VSP]), shallow sediment surveying, and shallow hazard assessment. The activities are to take 

place in different water depths (shallow water, shelf, slope, and deep ocean environments) and in different 

seasons of the year. 

Six acoustic sources were considered for the modeling study to provide example acoustic fields for 

different types of G&G exploration activities. The sources are large and small airgun arrays, side-scan 

sonar, boomer, chirp subbottom profiler, and multibeam depth sounder. 

Twenty-two modeling sites were defined throughout the Area of Interest (AOI). The water depth at 

the sites varied from 30 to 5,400 meters (m). Two types of bottom composition were considered: sand 

and clay, their selection depending on the water depth at the source. Twelve possible sound speed 

profiles for the water column were used to cover the variation of the sound velocity distribution in the 

water with location and season. Thirty-five distinct propagation scenarios resulted from considering 

different sound speed profiles at some of the modeling sites. Multiple sources were modeled for each 

scenario, yielding a total of 105 acoustic field estimates. 

Two acoustic propagation models were employed to estimate the acoustic field radiated by the sound 

sources. A version of JASCO’s Marine Operations Noise Model (MONM) based on the 

Range-dependent Acoustic Model (RAM) parabolic-equations model, MONM-RAM, was used to 

estimate the sound exposure levels (SELs) for low-frequency sources (below 2 kilohertz [kHz]) such as 

airgun arrays and boomer. A version based on the BELLHOP ray-trace model, MONM-BELLHOP, was 

used to model the sound propagation from mid- and high-frequency sources. Both models take into 

account the geoacoustic properties of the sea bottom, vertical sound speed profile in the water column, 

range-dependent bathymetry, and the directivity of the source. 

The directional source levels (SLs) for the airgun arrays were modeled using the Airgun Array Source 

Model (AASM) based on the specifications of the source such as the arrangement and volume of the 

guns, firing pressure, and depth below the sea surface. The directivity function of the high-frequency 

sources was modeled numerically from technical specifications such as beam width, number of beams, 

and main beam axis direction; these were obtained from the manufacturer’s product specification sheets 

or through direct contact with the manufacturer. The modeled directional SLs were used as the input for 

the acoustic propagation model. 

2. BASICS OF UNDERWATER ACOUSTICS 

2.1. ACOUSTIC METRICS

Various sound level metrics are commonly used to express the loudness of noise and estimate its 

effects on marine life. The three primary metrics of importance in this study are peak pressure, 

root-mean-square (rms) sound pressure level (SPL), and SEL. Some of the criteria used to assess 

potential bioacoustic impacts on marine species are expressed in terms of sound pressure; most relevantly, 

the safety and disturbance thresholds currently applied to marine seismic surveys by the U.S. National 

Marine Fisheries Service (NMFS) are based on the rms SPL metric as adapted for impulsive sound 

sources. Other criteria proposed in more recent studies, like Southall et al. (2007), place greater emphasis 

on sound exposure and define impact thresholds in terms of the SEL metric. 

The peak pressure is defined as the maximum absolute value of the amplitude of a pressure time 

series p(t). 
D-2 Atlantic G&G Programmatic EIS 

The rms SPL (dB re 1 μPa, [American National Standard Institute] ANSI symbol Lp) is the rms of the 

pressure level, p(t), received at a location over a time interval, T: 















  

T

p dttp T

L )( 1 log10 2

10 (1) 

The rms SPL can be thought of as a measure of the average pressure or as the “effective” pressure 

over the duration of an acoustic event, such as a single acoustic pulse. Because the time interval, T, is 

used as a divisor, pulses that are more spread out in time have a lower rms SPL for the same total acoustic 

energy. The time interval, T, is conventionally defined as the “90 percent energy pulse duration” rather 

than a fixed time window (Malme et al., 1986, Greene, 1997, McCauley et al., 1998). 

For a pure sine wave the peak pressure (dB re 1 μPa, ANSI symbol Lpk) and rms SPL are related 

through a simple expression (Laughton and Warne, 2003): 

)( dB3 1 2log10 2

10 













   p

T

pk Ldttp T

L (2) 

Sound exposure level (dB re 1 μPa2·s, ANSI symbol LE) is the time-integral of the square pressure 

over a fixed time interval, T: 















  

T

LE )(log10 dttp2

10 (3) 

Sound exposure level represents the total acoustic energy delivered over the duration of an acoustic 

event. 

Because the rms SPL and SEL are both computed from the integral of square pressure, these metrics 

are related numerically by a simple expression which depends only on the duration of the integration time 

interval T: 

LL T  Ep 10   log10 (4) 

For continuous sound sources, a time interval of one second is conventionally used, and the rms SPL 

is equal to the SEL. For impulsive sources, an objective definition of pulse duration is needed when 

defining the rms SPL. As previously mentioned, the pulse duration is conventionally taken to be the 

interval during which 90 percent of the pulse energy is received at a location from the source. 

2.2. MAJOR FACTORS AFFECTING UNDERWATER SOUND PROPAGATION

The propagation of sound in the ocean environment is a complex phenomenon to model. Multiple 

factors can affect the response of the medium to an acoustic wave and the propagation loss of acoustic 

energy. Some factors, such as geometric spreading, refraction, and absorption are well understood and 

their influence can be fairly readily calculated. Others, such as scattering, can be difficult to quantify 

because of their dependence on fine-scale features of the local environment; it is possible, however, to 

estimate and predict their effect using more empirical approaches. In the sections that follow, the 

principal factors affecting sound propagation in the ocean are briefly discussed in terms of their numerical 

estimation. 

2.2.1. Geometric Spreading 

In a homogeneous free space the wave front moving away from a point-like source has the form of a 

sphere, whose area (A) increases proportionally to the square of the distance ( 2 A  R ). In turn, the 

received pressure is inversely proportional to the square root of the area (  2/1  Ap ). Therefore, in a free 

space the received pressure is inversely proportional to the distance from the source ( 1  Rp ). In terms 

of the sound level in decibel, this means that the transmission loss (TL) due to spherical spreading is 

equal to log20 10 R . 
Acoustic Modeling Report D-3 

Once the acoustic wave front reaches the seafloor, the spreading can no longer be considered 

spherical. In the water column, constrained by the sea surface and the sea bottom and at distances greater 

than the water depth, the acoustic wave front can be approximated more closely as a cylinder. The area of 

the side of a cylinder is proportional to the radius ( A R), and the received pressure is thus inversely 

proportional to the square root of the distance (  2/1  Rp ). In decibel terms, the TL due to cylindrical 

spreading is therefore equal to 2/1

10 log20 R or log10 10 R . 

In the oceanic environment, the TL due to geometric spreading of the acoustic wave front is generally 

calculated as spherical spreading for ranges from the source up to the water depth, and as cylindrical 

spreading beyond that distance. 

2.2.2. Absorption 

As sound waves propagate they interact at a molecular level with the constituents of sea water 

through a range of mechanisms, resulting in absorption of some of the sound energy (Thorp, 1965; Fisher 

and Simmons, 1977; Francois and Garrison, 1982a; Francois and Garrison, 1982b; Medwin, 2005). This 

occurs even in completely particulate-free waters and is in addition to energy losses from scattering by 

objects such as zooplankton or suspended sediments. The absorption coefficient depends on such factors 

as temperature, salinity, and pressure, and is different for acoustic waves of different frequencies. 

The loss of sound energy by absorption is expressed as an attenuation coefficient in units of decibels 

per kilometer (dB/km). This coefficient is computed from empirical equations and increases generally 

with the square of frequency. 

A representative curve of absorption loss as a function of frequency is shown in Figure D-1. The 

absorption of the acoustic wave energy is virtually nil in the low-frequency range (below 500 hertz [Hz]). 

It starts having a noticeable effect (at least 1 dB over ranges of 10-20 km) at frequencies above 1 kHz. 

The absorption loss increases markedly for higher frequencies; for a 100 kHz acoustic signal the 

absorption loss can exceed 30 dB over just 1 km kHz. In the context of this study the absorption loss is 

an important factor for the high-frequency electromechanical sources whereas it plays virtually no role in 

the attenuation of sound from airgun sources. 

Figure D-1. Sample Plot of Absorption Loss Versus 

Frequency (T° = 15 °C, Salinity = 33 ppt, 

z = 50 m). 

2.2.3. Refraction 

Refraction is a change of direction in a propagating wave because of spatial variations in sound speed 

within the medium. As a wave travels across a sound speed interface or gradient, portions of the wave 

front travel at different speeds, resulting in bending of the ray path (Medwin, 2005). The ray path bends 

away from a region with a higher sound speed toward a region with a lower sound speed. By affecting

travel paths within the medium, refraction can alter the angle of arrival of the sound at a receiver as well

as the angle of incidence upon boundaries (e.g., the seafloor). 
D-4 Atlantic G&G Programmatic EIS 

In order for refraction to occur, the medium must exhibit a spatial variation of the sound velocity over 

a scale comparable to the wavelength of the propagating wave. The major variables affecting the sound 

speed in sea water are the temperature, pressure, and salinity. The dependence is direct for all three 

variables; with an increase of the parameter, the sound speed also increases. 

Both temperature and pressure in the ocean have significant variation with depth, resulting in a spread 

of the sound velocity in the water column that can exceed a 60 meters per second (m/s) differential 

between maximum and minimum. As the physical parameters of the water can vary with time over a 

daily or seasonal cycle, so does the sound speed. The longer the period of the variation, the deeper the 

water layers that can be affected by it. In general, seasonal variations of the sound speed can be observed 

to depths up to 300 m. Water depths of more than 1,200 m exhibit a uniform sound speed gradient on a 

global scale. 

Figure D-2 presents an example of a sound speed profile that can be observed in the ocean. Seasonal 

variations occur in the mixed layer, which, depending on ambient conditions, can have either a positive or 

negative vertical sound speed gradient or none at all. During cold months of the year when temperature 

in the upper mixed layer increases with depth, upward refracting conditions can be induced by the 

positive sound speed gradient in the top water layer. In such conditions the sound tends to be channeled 

in the near-surface layer, referred to as a surface duct, as it is repeatedly reflected downward at the water 

surface and refracted upward by the positive sound speed gradient (Medwin, 2005). In the underlying 

thermocline region both temperature and sound speed decline, but below this, the temperature is constant 

and sound speed begins to increase again with depth. The sound velocity minimum results in acoustic 

refraction from both below and above toward the depth at which the minimum occurs, forming a 

propagation channel. This allows sound to travel without interaction with either the bottom or the sea 

surface, significantly reducing TL. The deep sound channel is an important stable channel for long-range 

propagation, allowing low-frequency sound to travel thousands of kilometers (Medwin, 2005). In 

shallow continental shelf regions, the water depth is not sufficient to form a deep sound channel. Sound 

propagation in such regions is, in general, strongly affected by seasonal and daily temperature changes. 

Figure D-2. Generic Sound Speed Profile with Some 

Common Features Defined. 

In deep ocean areas, features of the acoustic field known as convergence zones can be formed 

because of strong refractive conditions in the deep isothermal layer. Rays emitted from the source at 

different angles can be focused by refraction in certain volumes, increasing the overall RLs compared 

with the surrounding areas. The increase can be as high as 20 dB; such convergence zones, however, are 

localized. An example of an acoustic field with convergence zones is shown in Figure D-3. In the 

figure, the convergence zone where the received acoustic level reaches a local maximum can be observed 
Acoustic Modeling Report D-5 

near the surface at 65 and 130 km from the source; in a cross section it would have the form of a ring with 

a width of several hundred meters and a height of several tens of meters. 

Figure D-3. Example of an Acoustic Field from an Airgun Array Source with Convergence Zones. 

2.2.4. Scattering 

Scattering is a general term that covers several types of dispersive phenomena arising from the 

interaction of a propagating wave front with inhomogeneities in the medium (e.g., suspended particulates, 

bubbles, buried objects, air-sea or sea-sediment interfaces). Sound energy arriving at an object may bend 

around it (diffraction) and/or be scattered back toward the source (backscattering) or in other directions. 

For complex objects (e.g., a rough seafloor), the nature of these interactions can be quite complicated, as 

individual portions of a wave front are scattered differently (Medwin, 2005). However, if the acoustic 

wavelength is much greater than the scale of the non-uniformities in the medium (as is most often the case 

for low-frequency sounds) the effect of scattering on propagation loss is negligible. As the source 

spectral maximum of airgun arrays is below 200 Hz, sound propagation from such sources is virtually 

unaffected by scattering. In contrast, scattering loss effects are noticeable for electromechanical sources 

operating at high frequencies – several kHz and higher. 

2.2.5. Bathymetry 

Water depth is very influential on sound propagation, particularly at frequencies below a few kHz. In 

shallow water (less than ~100 m depth) acoustic propagation loss is dominated by reflection, 

transmission, and scattering of sound at the seabed. In deep water (greater than ~1 km depth) sound 

propagation is largely driven by refraction in the water column. At intermediate water column depths, 

sound propagation is influenced by a combination of these factors. 

Low-frequency acoustic waves may not be able to propagate through a shallow water column even in 

otherwise non-favourable conditions. If the wavelength of the sound is four times greater than the water 

depth, mode cut-off does occur (essentially the medium cannot support the oscillation) and the 

TL increases drastically compared to higher frequency waves (Clay and Medwin, 1977). 

Also, as discussed in an earlier section, the type of geometric spreading of the acoustic wave front is 

dependent on the water depth, which defines at which range from the source spherical spreading switches 

to cylindrical spreading. The TL in the spherical spreading regime is twice as large as in the cylindrical 

one, so the bathymetry can be very influential on propagation loss for this reason alone. 

2.2.6. Source Depth 

The radiated power of an underwater sound emitter depends on the position of the source below the 

sea surface. The propagation model used is designed to fully account for the source depth. The 
D-6 Atlantic G&G Programmatic EIS 

effectiveness of the source at a specific frequency, defined as the ratio of radiated power to the nominal 

power of the source placed in a free space, increases with depth and depends on the ratio of the source 

depth to the acoustic wavelength (zs  ) (Brekhovskikh and Lysanov, 2003). The effectiveness increases 

approximately linearly from 0 at  0 s z reaching value of 1.0 at   41 s z and 1.2 at zs   83 . For 

example, the effectiveness of a broadband source placed at 10 m depth with 1,500 m/s sound velocity will 

be 1.2 at 56 Hz and only about 0.27 at 10 Hz. 

2.2.7. Bottom Loss 

Bottom loss is the amount of the original acoustic wave energy that is lost at the water-sediment 

interface through coupling of the sound into the sediment. Bottom loss or TL is the complement of the 

reflection coefficient, to be defined below. 

An acoustic wave travelling in a medium can be reflected from an interface at which abrupt change in 

media parameters is observed. Generally at the interface only a portion of the total acoustic energy is 

reflected back and the rest is transmitted past the interface. The reflection coefficient is the ratio of the 

amount of the reflected energy to the original energy of an incoming acoustic wave. 

The reflection coefficient depends on the discrepancy of the acoustic impedances (defined as the 

product of density and sound velocity) of the media on each side of the interface. The greater the change 

of acoustic properties between the media, and hence the mismatch of the impedances, the closer to unity 

is the reflection coefficient. This coefficient also depends on the incident angle of the acoustic wave; it 

has its minimal value when the incident angle is 90° (normal to the interface) and can reach unity at 

sufficiently glancing angles for certain types of interface. 

For the purpose of numerical modeling of sound propagation, the reflection coefficient or bottom loss 

can be calculated exactly given the properties of the media and the incident angle. In practice, however, 

there is often uncertainty associated with the estimation of these parameters. The spatial variation of 

sediment properties can also be significant, which further complicates the estimations. Certain rules of 

thumb apply to the approximate gauging of bottom loss: since the sound velocity and density of a 

sediment both increase with grain size, resulting in greater impedance mismatch relative to the water, the 

bottom loss for sediments with larger grain size is lower than for the sediments with smaller grain size. In 

general, a sand bottom is more reflective and thus less acoustically absorptive than a clay bottom. 

2.3. ACOUSTIC IMPACT CRITERIA

2.3.1. M-Weighting 

The potential for anthropogenic underwater noise to affect marine species depends on the species’ 

ability to hear the sounds produced (Ireland et al., 2007). Noises are less likely to disturb animals if they 

are at frequencies that the animal cannot hear well. An exception is when the sound pressure is so high 

that it can cause physical injury. For non-injurious sound levels, frequency weighting curves based on 

audiograms may be applied to weight the importance of sound levels at particular frequencies in a manner 

reflective of the receiver’s sensitivity to those frequencies (Nedwell and Turnpenny, 1998). 

An NMFS-sponsored Noise Criteria Committee has proposed standard frequency weighting curves — 

referred to as M-weighting filters — for use with marine mammal species (Gentry et al., 2004). 

M-weighting filters are band-pass filter networks that are designed to reduce the importance of inaudible 

or less-audible frequencies for four marine mammal functional hearing groups: 

1. Low-frequency cetaceans; 

2. Mid-frequency cetaceans; 

3. High-frequency cetaceans; and 

4. Pinnipeds. 

The amount of discount applied by M-weighting filters for less-audible frequencies is not as great as 

would be indicated by the corresponding audiograms for these groups of species. The rationale for 

applying a smaller discount than would be suggested by the audiogram is in part because of an observed 

characteristic of mammalian hearing that perceived equal loudness curves increasingly have less rapid 

roll-off outside the most sensitive hearing frequency range as sound levels increase. This is the reason 
Acoustic Modeling Report D-7 

that C-weighting curves for humans, used for assessing very loud sounds such as blasts, are flatter than 

A-weighting curves used for quiet to mid-level sounds. Additionally, out-of-band frequencies, though 

less audible, can still cause physical injury if pressure levels are very high. The M-weighting filters 

therefore are primarily intended to be applied at high sound levels where effects such as temporary or 

permanent hearing threshold shifts may occur. The use of M-weighting should be considered 

precautionary (in the sense of overestimating the potential for an effect) when applied to lower level 

effects such as onset of behavioral response. Figure D-4 shows the decibel frequency weighting of the 

four standard underwater M-weighting filters. 

Figure D-4. Standard M-Weighting Curves for Low-, Mid-, and High-Frequency Cetaceans and 

Pinnipeds Underwater. 

The M-weighting filters have unity gain (0 dB) through the pass band, and their high- and 

low-frequency roll offs are approximately –12 dB per octave. The amplitude response in the frequency 

domain of the M-weighting filters is defined by: 

dB11log20)( 2

2

2

2

10 































 













  

hi

lo

f

f

f

f fG (5) 

The roll off and pass band of these filters are defined by the parameters flo and fhi. The parameter 

values of the standard M-weighting curves are presented in Table D-1. 
D-8 Atlantic G&G Programmatic EIS 

Table D-1 

 

Low-Frequency (flo) and High-Frequency (fhi) Cutoff Parameters 

for Standard Marine Mammal M-Weighting Curves 

(Southall et al., 2007) 

M-Weighting Filter flo (Hz) fhi (Hz) 

Low-frequency cetaceans 7 22,000 

Mid-frequency cetaceans 150 160,000 

High-frequency cetaceans 200 180,000 

Pinnipeds underwater 75 75,000 

The amplitude response of the M-weighting filter is calculated separately for each modeled frequency 

and added to the received level at that specific frequency to obtain the M-weighted received level: 

fGfRLfRL )()()( MW   (6) 

Since the amplitude response of the M-weighting filter calculated using Equation (5) is a negative 

value, the M-weighted received level is lower than the unweighted one. 

2.3.2. Consideration of the Minimum Integration Time 

The numerical models used for estimating the received levels assume that a virtual receiver does not 

have a limit on the minimum integration time and therefore the integration time used for the calculation of 

rms SPL (see Equation [2]) can be as small as the actual length of the pulse emitted by the source. When 

assessing the impact of the acoustic source on marine mammals it is important to take the specific 

properties of the marine mammal hearing apparatus into consideration. 

As summarized by Au and Hastings (2008), when receiving tone pulses, the mammalian ear behaves 

like an integrator with an “integration time constant.” Energy is summed over the duration of a pulse 

until the pulse is longer than the integration time constant. Studies of bottlenose dolphins by Johnson 

(1968) indicate an integration time constant of approximately 100 ms. Richardson et al. (1995) 

(Chapter 8.2.4) summarized a number of studies that compared the effect of short signals (less than 

100 ms) with the effect of prolonged signals on marine mammals. It was observed that the thresholds for 

pulses of 0.2 ms duration were ~10-20 dB poorer (i.e., higher). For even shorter pulses the thresholds can 

increase by as much as 40 dB. 

It can be concluded that the increase in the thresholds with decreasing the signal duration exists 

because of minimum integration time limitation caused by the specifics of the hearing apparatus of some 

marine mammals. As such, when calculating the apparent received levels with Equation (2), the 

minimum integration time should be used for the time interval value T instead of the actual pulse 

duration. The adjustment for the minimum integration time can be calculated by the following formula: 















 

MIT

pulse

RL app act T

T

RLRL 10 log10 , (7) 

where RLapp is the apparent received level that takes into consideration the minimum integration time, 

RLact is the actual received level calculated using actual pulse duration, Tpulse is the pulse length, and TMIT

is the minimum integration time. The adjustment is a negative value and should be used only in case 

Tpulse < TMIT.

2.3.3. National Marine Fisheries Service Criteria 

The NMFS considers two levels of harassment to the marine mammals: Level A (injury) and Level B 

(disturbance). According to the 1994 Amendments to the Marine Mammal Protection Act (MMPA) of 

1972, Level A Harassment is defined as “any act that injures or has the significant potential to injure a 

marine mammal or marine mammal stock in the wild.” Level B Harassment is defined as “any act that 

disturbs or is likely to disturb a marine mammal or marine mammal stock in the wild by causing 

disruption of natural behavioral patterns, including, but not limited to, migration, surfacing, nursing, 
Acoustic Modeling Report D-9 

breeding, feeding, or sheltering, to a point where such behavioral patterns are abandoned or significantly 

altered.” 

The NMFS (2005) specified that Level A Harassment for pulsed sources occurs when an animal is 

exposed to sound pressure levels of 180 dB re 1 μPa rms (for cetaceans) or 190 dB re 1 μPa rms 

(for pinnipeds). The criterion of 160 dB re 1 μPa rms SPL is considered as Level B Harassment for both 

mammal groups for pulsed sources. 

The 180-160 dB criteria were thought to be well understood by public and easily calculated from 

standard propagation models (Federal Register, 2005). Being expressed in rms units, the criteria take into 

account not only the energy of the pulse, but also the length of the pulse (see Equation [1]). The exposure 

levels need to be calculated using the unweighted acoustic signal, i.e., they do not take into account 

different hearing ability of the animals at different frequencies. The disadvantage of such a criterion is 

that it does not take into account certain important attributes of the exposure such as duration, frequency, 

or repetition rate (Federal Register, 2005). 

2.3.4. Southall Criteria 

In order to address the shortcomings of the 180-160 dB rms SPL criteria, the Noise Criteria Group 

was established, which was sponsored by NMFS. The goal of the Noise Criteria Group was to develop 

updated noise exposure criteria based on solid scientific evidence. In 2007 the findings of the Group were 

published by an group of scientists led by Brandon Southall (Southall et al., 2007). In the publication 

new noise impact criteria were introduced, now commonly referred to as ‘Southall criteria.’ 

The Southall criteria (Table D-2) are based on numerous data collected in the course of controlled 

and uncontrolled experiments during which different species were exposed to various levels of sound. 

The observations were made for the occurrence of permanent threshold shift (PTS) or temporary 

threshold shift (TTS) in animals’ hearing. As a result, the criteria for injury were suggested. In terms of 

behavioral impacts, Southall et al. (2007) did not propose criteria for sources other than a single impulse 

(e.g., explosion) for the reasons of context-dependence and other complexities in the nature of behavioral 

responses and available literature. 

Table D-2 

 

Southall Criteria for Injury 

(Southall et al., 2007) 

Injury Marine Mammal Group Peak Pressure Sound Exposure Level 

Low-frequency cetaceans 230 dB re 1 μPa (flat) 198 dB re 1 μPa2·s (Mlf) 

Mid-frequency cetaceans 230 dB re 1 μPa (flat) 198 dB re 1 μPa2·s (Mmf) 

High-frequency cetaceans 230 dB re 1 μPa (flat) 198 dB re 1 μPa2·s (Mhf) 

Pinnipeds underwater 218 dB re 1 μPa (flat) 186 dB re 1 μPa2·s (Mpw) 

The injury criteria are based both on peak pressure of the acoustic wave, expressed in dB re 1 μPa, 

and the total SEL, expressed in dB re 1 μPa2

·s. In order to comply with the criteria, the characteristics of 

the acoustic wave should not exceed either or both. 

Two different levels were established for cetaceans and pinnipeds, with the levels for pinnipeds being 

lower. Prior to calculation of the sound exposure level appropriate M-weighting filter (see Section 2.3.1) 

would be applied to the acoustic signal to take into account hearing specifics of different mammal groups. 

During the calculations of the sound exposure level the length of the pulse is not considered, only the total 

energy released during the pulse event (see Equation [3]). 
D-10 Atlantic G&G Programmatic EIS 

3. ACOUSTIC SOURCES 

The acoustic sources covered in the programmatic modeling study can be subdivided into two major 

groups: 

 airgun sources; and 

 electromechanical sources. 

An airgun source can consist of a single device, but most often it is made up of an array of airguns. It 

is considered a low-frequency source since most of its acoustic energy is radiated at frequencies below 

200 Hz. Airgun arrays are broadband emitters, with source spectra spanning a number of third-octave 

bands. A single airgun is an omnidirectional source, i.e. the amplitude of the acoustic wave emitted from 

the source is uniform in all directions. An airgun array, on the other hand, does exhibit directionality 

because of the varying delays between signals from the spatially separated airguns in different directions. 

The main specification of an airgun, which defines its broadband SL and spectral content, is the volume 

of the air chamber. 

Electromechanical sources are considered mid- or high-frequency emitters. They usually have one or 

two (sometimes three) main operating frequencies, which fall in the range from 2 to 900 kHz. The 

acoustic energy emitted outside the main operating frequency band in most of these devices is negligible; 

they can therefore usually be considered narrow band sources. High-frequency electromechanical sources 

are highly directive with beam widths as narrow as a few degrees. Electromechanical sources include 

side-scan sonars, subbottom profilers, single and multibeam depth sounders, boomers, etc. 

The list of acoustic sources addressed in this study is presented in Table D-3. The operating 

frequencies and operational application are also provided. 

Table D-3 

 

List of Acoustic Source Types Modeled in This Study Indicating Representative Equipment Types, 

Operating Frequencies, and Survey Application 

Modeled at Sites 

Type of Acoustic Source Operating 

Frequencies Oil and Gas 

Exploration 

Renewable 

Energy Marine Minerals 

Large airgun array (5,400 in3) 10-2,000 Hz ● -- -- 

Small airgun array (90 in3) 10-2,000 Hz ● -- -- 

Boomer 200-16,000 Hz ● ● ●

Side-scan sonar 100, 400 kHz ● ● ●

Chirp subbottom profiler 3.5, 12, 200 kHz ● ● ●

Multibeam depth sounder 240 kHz ● ● ●

3.1. AIRGUN SOURCES

3.1.1. Seismic Survey Overview 

Marine seismic surveys using airgun sources are capable of producing high-resolution, 3D images of 

geological stratification down to several kilometers depth, and have thus become an essential tool for 

geophysicists studying the Earth’s crust. Seismic airgun surveys can be divided into two types, 2D and 

3D, according to the type of data that they acquire. Two-dimensional surveys are so called because they 

only provide a 2D cross-sectional image of the Earth’s structure; they are characterized operationally by 

large spacing between survey lines, on the order of a kilometer or more. Three-dimensional surveys, on 

the other hand, rely on very dense line spacing, of the order of a few hundred meters or less, to provide a 

3D volumetric image of the underlying geological structures. 

The total volume of the airgun array source and the volume of individual airguns for a typical 2D 

survey are usually larger than for a typical 3D seismic survey. Two-dimensional surveys aim at deeper 

imaging of the geological structures at the expense of resolution. 
Acoustic Modeling Report D-11 

A typical seismic survey, either 2D or 3D, is operated from a single survey ship that tows both the 

seismic source and the receiver apparatus. Up to tens of individual airguns in the source array are fired 

simultaneously in order to project a high-amplitude seismo-acoustic pulse into the ocean bottom. The 

receiver equipment usually consists of one or more streamers, often several kilometers in length, that 

contain hundreds of sensitive hydrophones for detecting echoes of the seismic pulse reflected from 

subbottom features. In some cases, the receiving equipment consists of cabled seismometers placed on 

the ocean floor. For other seismic surveys, both streamers and ocean-bottom seismometers are used. 

The majority of the underwater sound generated by a seismic survey is attributable to the airgun 

array, the survey vessel itself contributing very little in relative terms to the overall sound field. Airgun 

arrays are broadband acoustic sources that project energy over a wide range of frequencies, from under 

10 Hz to over 5 kHz. Most of the energy, however, is concentrated in the frequency range below 200 Hz. 

The constituent airguns in the array are geometrically arranged so as to project the maximum amount of 

seismic energy vertically into the seafloor. A significant portion of the sound energy from the array is, 

nonetheless, emitted at off-vertical angles and propagated into the surrounding environment. The 

frequency spectrum of the sound propagating near-horizontally can differ markedly from that of the sound 

directed downward. There can also be substantial differences in the intensity and frequency spectrum of 

sound projected in different horizontal directions. 

3.1.2. Airgun Operating Principles 

An airgun is a pneumatic sound source that creates predominantly low-frequency acoustic impulses 

by generating bubbles of compressed air in water. The rapid release of highly-compressed air (typically 

at pressures of ~2,000 psi) from the airgun chamber creates an oscillating air bubble in the water. The 

expansion and oscillation of this air bubble generates a strongly-peaked, high-amplitude acoustic impulse 

that is useful for seismic profiling. The main features of the pressure signal generated by an airgun, as 

shown in Figure D-5, are the strong initial peak and the subsequent bubble pulses. The amplitude of the 

initial peak depends primarily on the firing pressure and chamber volume of the airgun, whereas the 

period and amplitude of the bubble pulse depend on the chamber volume and firing depth. 

Figure D-5. Overpressure Signature for a Single Airgun, Showing the Primary Peak and 

the Bubble Pulse. 
D-12 Atlantic G&G Programmatic EIS 

As mentioned earlier, airguns are designed to generate most of the acoustic energy at frequencies less 

than ~200 Hz, which are most useful for seismic penetration beneath surficial seabed sediment layers. 

Because of their impulsive nature, airgun sources inevitably generate sound energy above 200 Hz, 

although the energy output at those frequencies is substantially less than at low frequencies. In general, 

the predominant frequency output of an airgun is inversely dependent on its volume. 

Zero-to-peak (0-p) SLs for individual airguns range typically between 220 and 235 dB re 1μPa at 1m 

(~1–6 bar· m), with larger airguns generating higher peak pressures than smaller ones. The peak pressure 

of an airgun pulse, however, only increases with the cubic root of the chamber volume. Furthermore, the 

amplitude of the subsequent bubble pulses also increases with the volume of the airgun and constitutes an 

undesirable feature of the airgun signal as it smears subbottom reflections. In order to increase the pulse 

amplitude (to “see” deeper into the earth), geophysicists generally combine multiple airguns together into 

arrays. Airgun arrays provide several advantages over single airguns for deep geophysical surveying: 

 the far-field peak pressure of an airgun array in the vertical direction increases nearly 

linearly with the number of airguns; 

 the geometric lay-out of airgun arrays can be optimized to project maximum peak 

levels toward the seabed (i.e., directly downward), whereas single airguns produce 

nearly omnidirectional sound; and 

 by using airguns of several different volumes, airgun arrays can be “tuned” to 

increase the amplitude of the primary peak and simultaneously decrease the relative 

amplitude of the subsequent bubble pulses. 

3.1.3. Airgun Array Source Levels 

The far-field pressure generated by a seismic airgun array is substantially greater than that of an 

individual airgun, but is also strongly angle-dependent relative to the array axis. An array of thirty guns, 

for example, can have a zero-to-peak SL of 255 dB re 1 μPa at 1m (~56 bar· m) in the vertical direction. 

This apparently high value for the SL can lead to erroneous conclusions about the impact on the marine 

environment for the following reasons: 

 peak SLs for seismic survey sources are usually quoted for the sound propagating 

vertically downward; because of the directional dependence of the radiated sound 

field, however, SLs for the sound propagating off to the sides of the array are 

generally lower; and 

 far field SLs do not apply in the near field of the array because an airgun array is a 

distributed source in which the sound from the individual airguns does not add 

coherently; sound levels in the near field are, in fact, lower than would be expected 

from far-field estimates. 

The acoustic SL of a seismic airgun array varies considerably in both the horizontal and vertical 

directions because of the complex interaction between the signals from the component airguns. One must 

account for this variability in order to correctly predict the sound field generated by an airgun array. If 

the source signatures and relative positions (in 3D) of the individual airguns are known, then it is possible 

to accurately compute the SL of an array in any direction by summing the contributions of the array 

elements with the appropriate time delays, according to their relative positions. This is the basis for the 

airgun array source model discussed in the next section. 

3.1.4. Airgun Array Source Model 

The current study makes use of a full-waveform AASM, developed by JASCO (MacGillivray, 2006), 

to compute the SL and directionality of the airgun array. The airgun model is based on the physics of the 

oscillation and radiation of airgun bubbles, as described by Ziolkowski (1970). The model solves in 

parallel, using a numerical integration scheme, a set of ordinary differential equations that define the 

airgun bubble oscillations. 

In addition to the basic bubble physics, the source model also accounts for non-linear pressure 

interactions between airguns, port throttling, bubble damping, and generator-injector (GI) gun behavior, 
Acoustic Modeling Report D-13 

as described by such authors as Dragoset (1984), Laws et al. (1990), and Landro (1992). The source 

model includes four empirical parameters that are tuned so that the model output matches observed airgun 

behavior. These parameters were fitted to a large library of real airgun data using a “simulated annealing” 

global optimization algorithm. The airgun data were obtained from a systematic study (Racca and 

Scrimger, 1986) that measured the signatures of Bolt 600/B guns ranging in volume from 

5 to 185 cubic inches (in3

). 

The airgun array source model requires several inputs, including the array layout, volumes, towing 

depths, and firing pressure. The output of the source model is a set of “notional” signatures for the array 

elements; these are the pressure waveforms of the individual airguns, compensated for the interaction 

with other airguns in the array, at a standard reference distance of 1 m. 

After the source model is executed, the resulting notional signatures are summed together with the 

appropriate phase delays to obtain the far-field source signature of the array. The far-field array 

signature, in turn, is filtered into third-octave pass bands to compute the SL of the array as a function of 

frequency band, fc, and propagation azimuth, θ: SL = SL(fc, θ). 

The interaction between the signals from individual airguns creates a directionality pattern in the 

overall acoustic emission from the array. This directionality is particularly prominent at frequencies from 

several tens to several hundred Hz; at lower frequencies the array appears omnidirectional, whereas at 

higher frequencies the pattern of lobes becomes too finely spaced to resolve. 

The propagation model, discussed in Section 4.1, calculates TL from an equivalent point-like 

acoustic source to receiver locations at various distances, depths, and bearings. As previously mentioned, 

however, the point-source assumption is not valid in the near field, where the output from the distinct 

array elements does not add coherently. The maximum extent of the near field of an array is given by the 

expression 

4

2 L Rnf  (8) 

Here, λ is the sound wavelength and L is the longest dimension of the array (Lurton, 2002, §5.2.4). 

For example, along the diagonal of the 3-string (18-airgun) array discussed below, L ≈ 22 m and so the 

maximum near field range is 80 m at 1 kHz (Rnf is less for lower frequencies). Beyond these ranges it is 

assumed that an array radiates like a directional point source and can be treated as such for the purpose of 

propagation modeling. 

3.1.5. Large Airgun Array 

A 5,400 in3 airgun array was taken as a representative example of a large seismic source for oil and 

gas exploration. The configuration of the array and air gun volumes were suggested in the “MAI 

Discussion Points about Modeling Assumptions” document. 

The array has dimensions of 16 × 15 m and consists of 18 air guns placed in three identical strings of 

six air guns each (Figure D-6). The volume of individual air guns ranges from 105 to 660 in3

. Firing 

pressure for all elements is 2,000 psi. The depth below the sea surface for the array was set at 6.5 m. 

The array was modeled using the JASCO airgun array source model to compute notional source 

signatures and from them obtain third-octave band SLs as a function of azimuth angle. The resulting 

broadside and endfire (relative to the trackline) overpressure signatures and corresponding power 

spectrum levels are shown in Figure D-7. Horizontal third-octave band directionality plots are shown in 

Figure D-8. Specific characteristics of the 5,400 in3

 airgun array pressure signature are provided in 

Table D-4. 
D-14 Atlantic G&G Programmatic EIS 

Figure D-6. Layout of the 5,400 in3 Seismic Array (symbol sizes 

and labels indicate the volume of the airguns in cubic 

inches). 

Figure D-7. Predicted Overpressure Signature (left) and Power Spectrum (right) 

for the 5,400-in3

 Airgun Array in the Broadside and Endfire 

Directions (surface ghosts [effects of the pulse reflection at the 

water surface] are not included in these signatures). 
Acoustic Modeling Report D-15 

Figure D-8. Azimuthal Directivity Pattern of SLs for the 5,400-in3 Array at 

6.5-m Depth, Shown in Third-Octave Bands by Center Frequency 

(arrows indicate the front of the array and the solid black curves 

indicate the source levels in dB re 1 μPa2

 s as a function of angle in 

the horizontal plane, referenced to a fixed radial dB level scale 

[dashed circles]). 

Table D-4 

 

5,400-in3

 Airgun Array Pressure Characteristics from the AASM Model at 6.5-m Depth 

(surface ghost effects are excluded) 

Metric Forward Endfire Broadside 

Zero-Peak Pressure (dB re 1 Pa at 1 m) 247.7 246.7 

90% rms level (dB re 1 Pa at 1 m) 233.3 232.5 

90% rms duration (ms) 500 513 

SEL 10–2,000 Hz (dB re 1 Pa2 at 1 m) 224.7 224.7 

SEL 0–1,000 Hz (dB re 1 Pa2 at 1 m) 230.7 230.0 

SEL 1,000–2,000 Hz (dB re 1 Pa2 at 1 m) 181.7 181.8 
D-16 Atlantic G&G Programmatic EIS 

The directivity of the airgun arrays source is markedly dependent on the array configuration. The 

maximum pressure levels in each frequency band (over all directions), on the other hand, are less strongly 

dependent on the configurations, and can be considered as a function of the total volume of the array. In 

view of the generalized nature of this study, it was decided to remove the directivity from the source 

modeling by calculating the maximum level over all azimuths in each third-octave band and using those 

band levels for all directions. The resulting SLs for the 5,400 in3

 airgun are shown in Figure D-9. 

Figure D-9. Maximum Directional SLs in Each Third-Octave Band for 

the 5,400-in3

 Airgun Array. 

3.1.6. Small Airgun Array 

A 90 in3, two airgun array was taken as representative configuration for the purpose of modeling a 

small seismic source typically used for high-resolution geophysical (HRG) surveys of oil and gas 

exploration and development sites. The two guns were assumed to be 45 in3

 each, spaced 1 m from each 

other and deployed at a depth of 6.5 m. The source modeling considerations for the 90 in3

 airgun array 

were similar to the ones for the large airgun array (see Section 3.1.5), including the removal of the 

directivity from the source function by assuming that the maximum directional acoustic level in each 

third-octave band is emitted in all directions. 

Specific characteristics of the 90 in3

 airgun array pressure signature are provided in Table D-5. The 

observed maximum levels in third-octave bands for the 90 in3

 airgun array are shown in Figure D-10. 

Table D-5 

 

90-in3

 Airgun Array Pressure Characteristics from the AASM Model at 6.5 m Depth 

(surface ghost effects are excluded) 

Metric Forward Endfire Broadside 

Zero-peak Pressure (dB re 1 Pa at 1 m) 232.0 231.2 

90% rms level (dB re 1 Pa at 1 m) 215.9 215.8 

90% rms duration (ms) 247 248 

SEL 10–2,000 Hz (dB re 1 Pa2 at 1 m) 210.2 210.1 

SEL 0–1,000 Hz (dB re 1 Pa2 at 1 m) 210.3 210.2 

SEL 1,000–2,000 Hz (dB re 1 Pa2 at 1 m) 172.6 170.1 
Acoustic Modeling Report D-17 

Figure D-10. Maximum Directional SLs in Each Third-Octave Band for 

the 90-in3

 Airgun Array. 

3.2. ELECTROMECHANICAL SOURCES

Mid- and high-frequency underwater acoustic sources for geophysical measurements create an 

oscillatory overpressure through rapid vibration of a surface, using either electromagnetic forces or the 

piezoelectric effect of some materials. A vibratory source based on the piezoelectric effect is commonly 

referred to as a transducer, and may be capable of receiving as well as emitting functionality. 

The transducers are usually designed to excite an acoustic wave of a specific frequency, often in a 

highly directive beam. The directional capability increases with increasing operating frequency. The 

main parameter characterizing the directivity is the beam width, defined as the angle subtended by 

diametrically opposite “half power” (-3 dB) points of the main lobe. For different transducers the beam 

width can vary from 180° (almost omnidirectional) to only a few degrees. 

Transducers are usually produced with either circular or rectangular active surfaces. For circular 

transducers the beam width in the horizontal plane (assuming a downward pointing main beam) is equal 

in all directions. Rectangular transducers produce more complex beam patterns with variable beam width 

in the horizontal plane; two beam width values are usually specified for orthogonal axes. 

3.2.1. Beam Pattern Calculation 

The acoustic radiation pattern, or beam pattern, of a transducer is the relative measure of acoustic 

transmitting or receiving power as a function of spatial angle. Directionality is generally measured in 

decibels relative to the maximum radiation level along the central axis perpendicular to the transducer 

surface. The pattern is defined largely by the operating frequency of the device and the size and shape of 

the transducer. 

Beam patterns generally consist of a main lobe extending along the central axis of the transducer, and 

multiple secondary lobes separated by nulls. The width of the main lobe depends on the size of the active 

surface relative to the sound wavelength in the medium, with larger transducers producing narrower 

beams. Figure D-11 presents a 3D visualization of a typical beam pattern for a circular transducer. 
D-18 Atlantic G&G Programmatic EIS 

Figure D-11. Typical 3D Beam Pattern for a Circular 

Transducer ( Massa, 1999). 

The beam width is a key characteristic of transducers. It is generally defined as the total angular 

range where the sound pressure level of the main beam is within 3 dB of the on-axis peak power (Massa, 

1999). The true beam pattern of a transducer can only be obtained by in situ measurement of the emitted 

energy around the device, as shown in the example of Figure D-12. Such data, however, are not always 

readily available, and for modeling purposes it is often sufficient to estimate the beam pattern based on 

transducer theory. 

Figure D-12. 2D Polar Representation of a Beam Pattern Obtained by In Situ

Measurement (vertical slice) of a Transducer Used by Kongsberg 

(these sample measurements were obtained through personal 

communications with the manufacturer). 

3.2.2. Beam Pattern of a Circular Transducer 

The beam of an ideal circular transducer is symmetric about the main axis; the radiated level depends 

only on the depression angle. In this study, beam directivities were calculated from the standard formula 

for the beam pattern of a circular transducer (Kinsler et al., 1950; ITC, 1993). The directivity function of 

a conical beam, relative to the on-axis pressure amplitude, is given by: 
Acoustic Modeling Report D-19 

 

)sin(D

)sin(DJ )(R  



2 1 

 and bw

D

 

60 

, 

(9) 

where J1 is the Bessel function of the first order, Dλ is the transducer dimension in wavelengths of sound 

in the water, θbw is the beam width in degrees, and  is the beam angle from the transducer axis. The 

beam pattern of a circular transducer can be calculated from the transducer’s specified beam width or 

from the diameter of the active surface and the operating frequency. The calculated beam pattern for a 

circular transducer with a beam width of 20° is shown in Figure D-13. The gray scale represents the SL 

(in dB re 1 μPa at 1 m) and the declination angle is relative to a central vector (0°, 0°) pointing directly 

downward at the seafloor. 

Figure D-13. Calculated Beam Pattern for a Circular Transducer with a Beam 

Width of 20° (beam power function shown relative to the on-axis 

level, using the Robinson projection). 

Although some acoustic energy is emitted at the back of the transducer, the theory only accounts for 

the beam power in the front half space ( <90°) and assumes no energy directed into the back half space. 

The relative power at these rearward angles is significantly lower, generally by more than 30 dB, and 

consequently the emission in the back half space can be estimated by applying a simple decay rate, in dB 

per angular degree, which reduces the beam power at  = 90° to a value 30 dB lower than at  = 0°. 

This simple estimate of the beam power in the back half space allows a conservative estimate of the total 

beam power. 

3.2.3. Beam Pattern of a Rectangular Transducer 

Rectangular transducer beam directivities were calculated from the standard formula for the beam 

pattern of a rectangular acoustic array (Kinsler et al., 1950; International Transducer Corporation, 1993). 

This expression is the product of the toroidal beam patterns of two line arrays, where the directional 

characteristics in the along- and across-track directions are computed from the respective beam widths. 

The directivity function of a toroidal beam, relative to the on-axis pressure amplitude, is given by: 

 

)sin(L

)sin(Lsin )(R 

  





 and bw

L

 

50 

, 

(10) 

where L is the transducer dimension in wavelengths,  bw is the beam width in degrees, and  is the 

angle from the transducer axis. The beam pattern of a transducer can be calculated using either the 

specified beam width in each plane or the dimensions of the active surface and the operating frequency of 

the transducer. The calculated beam pattern for a rectangular transducer with along- and across-track 

beam widths of 4° and 10°, respectively, is shown in Figure D-14. 
D-20 Atlantic G&G Programmatic EIS 

Figure D-14. Calculated Beam Pattern for a Rectangular Transducer with a 4°×10° 

Beam Width (beam power function shown relative to the on-axis level, 

using the Robinson projection). 

3.2.4. Beam Pattern of a Multibeam System 

High-frequency systems often have two or more transducers, as is the case for side-scan sonars and 

swath bathymetry sonars. Typical side-scan sonar uses two transducers, with the central axes directed 

perpendicular to the track of the ship and at some depression angle to the horizontal plane. By contrast, 

multibeam bathymetry survey systems can have upwards of 100 transducers. Such systems generally 

utilize rectangular transducers and have a narrow beam width in the horizontal plane (0.2°–3°) and a 

wider beam width in the vertical plane. 

For multibeam systems, the beam patterns of individual transducers are calculated separately then 

combined into the overall pattern of the system based on the engagement type of the beams, which can be 

simultaneous or successive. If the beams are engaged successively, the SL of the system along a specific 

direction is assumed to be equal to the maximum SL realized from each of the individual transducers, 

whereas if the beams are engaged simultaneously, the beam pattern of the system is simply the sum of all 

beam patterns. Figure D-15 presents the predicted beam pattern for two rectangular transducers engaged 

simultaneously. In this example, the individual transducers have along- and across-track beam widths of 

1.5° and 50°, respectively. 

Figure D-15. Calculated Beam Pattern for Two Rectangular Transducers Engaged 

Simultaneously, with Individual Beam Widths of 1.5°×50°, and a 

Declination Angle of 25° (beam power function shown relative to the 

on-axis level, using the Robinson projection). 
Acoustic Modeling Report D-21 

3.2.5. Boomer 

3.2.5.1. Boomer Source Description 

Boomers consist of a circular piston moved by electromagnetic force; the emitter plate of a surface 

towed boomer system is shown in Figure D-16. The high voltage energy that excites the boomer plate is 

stored in a capacitor bank; operating voltages range from 1 to 6 kilovolts (kV), and the energy discharged 

for a single shot can vary from 50 joules (J) to 1,000 kilojoules (kJ). The typical pulse width is in order 

of tenths of a millisecond (Figure D-17). The narrow pulse allows the boomer to achieve high rms SPL 

(210–220 dB re 1 μPa at 1 m) with relatively low total energy input. The peak pressure level for a 

boomer with the input energy less than 400 J do not exceed 220 dB re 1 μPa at 1 m (Simpkin, 2005). 

Figure D-16. Surface Towed Boomer Source (Simpkin, 

2005). 

Figure D-17. Source Pulse of the AA201 

Boomer at 100 J Energy Output 

(Applied Acoustic Engineering 

Ltd., 2011). 

The amount of energy discharged is controlled by increasing either the voltage or the size of the 

capacitor. Increasing the voltage, for a given capacitance, shortens the pulse duration and thus shifts the 

spectral band of generated acoustic energy toward higher frequencies. Increasing the capacitance for a 

given voltage increases the pulse length and thus generates lower frequencies. In both cases the peak 
D-22 Atlantic G&G Programmatic EIS 

amplitude and broadband SL increase. By controlling the parameters of the applied electrical impulse, 

frequencies as high as 20 kHz can be generated. The power spectrum of the acoustic wave generated by a 

boomer source peaks at 1.5–5 kHz (Simpkin, 2005). Boomer systems can penetrate as deep as 200 m in 

soft sediments, with a resolution as small as 75 centimeters (cm) (Simpkin, 2005). Boomer sources show 

some directionality, which increases with the acoustic frequency; at frequencies below 1 kHz they can 

usually be considered omnidirectional. 

3.2.5.2. Acoustic Characteristics 

The emitting element of the boomer source is a boomer plate with the diameter of about 30–40 cm 

mounted on a catamaran-like sled as shown in Figure D-18 (Applied Acoustic Engineering Ltd., 2011). 

Because the boomer source is a circular piston surrounded by a rigid baffle, it cannot be considered a 

point-like source (Verbeek and McGee, 1995). The boomer is a strongly directive source for frequencies 

at which the boomer dimension is not small compared to the wavelength; by this criterion the boomer 

becomes directional at frequencies above 1 kHz. In order to produce estimates of the sound field for a 

generic boomer source, the specifications of the Applied Acoustics AA201 boomer were taken to 

represent a standard system. 

Figure D-18. Example of a Representative Boomer Plate 

System (Applied Acoustic Engineering Ltd., 

2011). 

The manufacturer’s product fact-sheet specifies an rms SPL of 212 dB re 1 μPa at 1 m at 200 J 

(maximum input energy) with a pulse duration less than 0.18 ms and a typical ping rate of 2–3 Hz 

(Table D-6). The peak source level was estimated based on the rms SPL source level using the relation 

between the peak and rms levels for a sine wave. The source level expressed in SEL units 

(dB re 1 μPa2

·s) was estimated based on the rms SPL and the pulse length using Equation (4). 
Acoustic Modeling Report D-23 

Table D-6 

 

Representative Boomer Specifications 

(source levels are provided for 200 J power input) 

Operational Frequency Range Broad Band: 200 Hz – 16 kHz 

Beam Widths (degrees) omnidirectional – 8° 

Maximum Energy Input (per shot) 300 J 

Maximum Power Input 600 W 

Pulse Length (at 200 J) 180 μs 

rms SPL (dB re 1 μPa at 1 m) 212 

Peak Level (dB re 1 μPa at 1 m) 215 

SEL (dB re 1 μPa2·s at 1 m) 174.6 

The power spectrum of the boomer signal and the beam width at different frequencies was estimated 

based on Simpkin’s (2005) study of the Huntec ’70 Deep Tow Boomer, a typical boomer plate of 

comparable dimensions. The estimated values are presented in Table D-7. 

Table D-7 

 

Estimated Source Levels (rms SPL) and Beam Width from the Representative Boomer 

Distributed into Twenty 1/3-Octave Bands 

(broad band source level is 212 dB 1 μPa at 1 m) 

Third-Octave Band Center 

Frequency (Hz) 

rms SPL 

(dB re 1 μPa at 1 m) 

SEL 

(dB re 1 μPa2

·s at 1 m) Beam Width 

200 196.0 158.6 omnidirectional 

250 196.4 159.0 omnidirectional 

315 197.1 159.7 omnidirectional 

400 197.7 160.3 omnidirectional 

500 198.5 161.1 omnidirectional 

630 199.4 162.0 omnidirectional 

800 200.0 162.6 omnidirectional 

1,000 200.8 163.4 omnidirectional 

1,250 201.5 164.1 105° 

1,600 201.6 164.2 78° 

2,000 201.9 164.5 60° 

2,500 201.4 164.0 47° 

3,150 200.8 163.4 37° 

4,000 200.1 162.7 29° 

5,000 198.9 161.5 23° 

6,400 197.8 160.4 18° 

8,000 196.1 158.7 14° 

10,000 192.8 155.4 11° 

12,800 186.8 149.4 9° 

16,000 176.8 139.4 8° 
D-24 Atlantic G&G Programmatic EIS 

The beam pattern calculations were then based on the standard formula for the beam pattern of a 

circular array (Equation [2]), with a decay rate in the back half space of 0.30 dB per degree from the 

horizontal plane, in order to reduce the back SL to -30 dB or less. Figures 19 and 20 show the flat image 

and vertical slice for the calculated beam pattern at (a) 1.25 and (b) 16.0 kHz. 

Figure D-19. Calculated Beam Pattern for the Representative Boomer at (a) 1.25 and 

(b) 16.0 kHz (beam power function shown relative to the on-axis level, 

using the Robinson projection). 

Figure D-20. Calculated Beam Pattern Vertical Slice for the Representative Boomer 

at (a) 1.25 and (b) 16.0 kHz; Across-Track Direction. 
Acoustic Modeling Report D-25 

The boomer source can be treated as an omnidirectional source for the frequencies of 1,000 Hz and 

lower. For frequencies higher than 1,000 Hz the directionality of the boomer was taken into account. 

The acoustic field projected by the boomer source was modeled using two propagation models: for 

frequencies of 1,000 Hz and below were modeled using MONM-RAM, while frequencies above 1,000 Hz 

were modeled using MONM-BELLHOP. 

3.2.6. Side-Scan Sonar 

The representative side-scan sonar is assumed to be a dual-frequency, side-scan sonar with two 

simultaneously-engaged transducers, each producing a full spectrum chirp signal (Figure D-21). The 

sonar can be operated in dual-frequency bands with central frequencies of 100/400 kHz. In order to 

produce estimates of the sound field for a generic side-scan sonar source, the specifications of the 

EdgeTech 4200-MP side-scan sonar were taken to represent a standard system (EdgeTech, 2011). 

Figure D-21. Example of a Representative Side-Scan Sonar System 

(EdgeTech, 2011). 

The sonar is installed inside a streamlined towfish that can be towed behind a vessel at different 

depths. The central axes of the two transducers are oriented perpendicular to the towing line in the 

horizontal plane, i.e., at 90° and 270° relative to the ship’s course. In the vertical plane, the central axes 

are tilted downward at 20° to the horizontal plane. The vertical beam width (across-track) is 50° for both 

frequencies. The horizontal beam width (along-track) varies between 0.4° and 1.26°, depending on the 

frequency and the operating mode. The relevant modeling parameters for the representative side-scan 

sonar system are presented in Table D-8. 

Table D-8 

 

Representative Side-Scan Sonar Parameters for the High-Speed and High-Definition Operating Modes 

100 kHz 400 kHz 

High-Speed High-Definition High-Speed High-Definition 

Output pulse energy (J) 4 2 

Pulse duration (ms) ≤20 ≤10 

rms SPL (dB re 1 μPa at1 m) 212 217 215 218 

Transducers 2 

Transducer along-track beam width 1.26° 0.64° 0.40° 0.30° 

Transducer across-track beam width 50° 

Transducer declination 20° 

Transducer azimuth 90°, 270° 
D-26 Atlantic G&G Programmatic EIS 

Each transducer’s beam directivity was calculated based on the standard formula for the beam pattern 

of a rectangular transducer. These 3D beam patterns were then summed to produce the final sonar beam 

pattern. Figure D-22 presents the calculated beam power function for the representative side-scan sonar 

system at 100 kHz, operating in (a) high-speed mode and (b) high-definition mode. Figure D-23 shows 

vertical slices of the beam pattern at 100 kHz in the along- and across-track directions, for the sonar 

operating in high-speed mode. 

Figure D-22. Calculated Beam Pattern for the Representative Side-Scan Sonar at 100 kHz, Operating in 

High-Speed Mode (beam power function shown relative to the on-axis level, using the 

Robinson projection). 

 

Figure D-23. Calculated Beam Pattern Vertical Slice for the Representative Side-Scan Sonar at 100 kHz 

Operating in High-Speed Mode; (left) Along- and (right) Across-Track Directions. 
Acoustic Modeling Report D-27 

Modeling Approach 

The side-scan sonar was modeled in the high-speed operation mode with 100/400 kHz frequencies. 

The SL for the purpose of modeling was chosen to be 223 dB re 1 μPa at 1 m in each of the two 

frequency bands, for a total broadband rms SPL of 226 dB re 1 μPa at 1 m. The tow depth of the source 

was chosen to be 5 m for modeling purposes. For the chosen rms SPL source level, the source levels in 

terms of the peak pressure level was calculated to be 229 dB re 1 μPa at 1 m. The SEL in each of the two 

bands was estimated at 206 dB re 1 μPa2

·s at 1 m considering the pulse length of 20 ms. 

With a very narrow beam width, the variability of the emitted energy in different directions in the 

horizontal plane is very high. A circular fan of modeling radials with variable angular step 

(see Table D-9) was created to a maximum range of 1.5 km from the source. The density of the radials 

was greater in proximity of the broadside, where beam variability is maximum, and lesser toward the 

endfire. The total number of rays modeled was 660. 

Table D-9 

 

Variable Angular Steps of the Modeling Radials in Different Sectors 

(only the steps for the first quadrant (0°-90°) are shown; those for the other quadrants were symmetrical) 

Sector Angular Step 

0° – 45° 1° 

45° – 80° 0.5° 

80° – 90° 0.2° 

The towing direction for each modeling site was selected individually based on the bathymetry, 

making the assumption that survey lines would run along the isobaths. The sound field was modeled 

using the MONM-BELLHOP acoustic propagation code. Since the SL was provided in rms SPL units, 

the output from the modeling was directly in terms of the rms SPL metric. 

3.2.7. Chirp Subbottom Profiler 

For the purpose of modeling a generic subbottom profiler source, the Knudsen Chirp 3260 model was 

chosen as representative example. This device is capable of working in three frequency bands 

simultaneously, providing subbottom images with acoustic signals at 3.5 kHz, 12 kHz, and 200 kHz. It 

uses two transducers, one operating at 3.5 kHz and the other at dual frequencies of 12 kHz and 200 kHz. 

The sonar head is mounted at the bottom of the ship’s hull, with the central axes of both transducers 

oriented directly downward. 

The SL of the 3.5 kHz transducer is 222 dB re 1 μPa at 1 m at 3 kilowatt (kW) output power level 

(LGL, 2010). The maximum output power levels for the 12 kHz and 200 kHz bands are 3 kW and 

0.5 kW respectively. As no direct information about SLs was available for the 12 kHz and 200 kHz 

bands, these were estimated based on the output power levels for these bands relative to the output power 

level and corresponding SL for the 3.5 kHz band. The specifications of the subbottom profiler used for 

the modeling are presented in Table D-10. 

The beam patterns were estimated using a mathematical model based on beam forming theory. Since 

the transducers are hull mounted, it was assumed that the most of the acoustic energy is emitted in the 

downward half-space and that the upward component is negligible. 
D-28 Atlantic G&G Programmatic EIS 

Table D-10 

 

Representative Chirp Subbottom Profiler Specifications 

 3.5 kHz 12 kHz 200 kHz 

Beam Circular 30° Rectangular 26° by 38° Circular 8° 

Output power 3 kW 3 kW 0.5 kW 

rms SPL (dB re 1 μPa at 1 m) 222 222 215.2 

Peak level (dB re 1 μPa at 1 m) 225 225 218.2 

SEL (dB re 1 μPa2·s at 1 m) 210.1 210.1 191.2 

Total peak level (dB re 1 μPa at 1 m) 228.2 

Ping duration (max) 64 ms 4 ms 

Figures D-24 through D-26 present the calculated beam power function for the representative chirp 

subbottom profiler at 3.5, 12, and 200 kHz, respectively. Vertical slices of the beam patterns for the same 

three frequencies are shown in Figures D-27 through D-29. 

Figure D-24. Calculated Beam Pattern for a Representative Chirp Subbottom 

Profiler at 3.5 kHz (beam power function shown relative to the onaxis level, using the Robinson projection). 

Figure D-25. Calculated Beam Pattern for a Representative Chirp Subbottom 

Profiler at 12 kHz (beam power function shown relative to the onaxis level, using the Robinson projection).
Acoustic Modeling Report D-29 

Figure D-26. Calculated Beam Pattern for a Representative Chirp Subbottom 

Profiler at 200 kHz (beam power function shown relative to the onaxis level, using the Robinson projection). 

Figure D-27. Calculated Beam Pattern Vertical Slice for a 

Representative Chirp Subbottom Profiler 

Operating at 3.5 kHz. 
D-30 Atlantic G&G Programmatic EIS 

 

Figure D-28. Calculated Beam Pattern Vertical Slice for a Representative Chirp Subbottom Profiler Operating at 

12 kHz (left); Along- and (right) Across-Track Directions. 

Figure D-29. Calculated Beam Pattern Vertical Slice for a 

Representative Chirp Subbottom Profiler 

Operating at 200 kHz. 

Modeling Approach 

The chirp subbottom profiler was modeled operating at all three frequencies simultaneously. The 

depth of the source was chosen to be 5 m. A total of 72 radial profiles with equal angular steps of 5° and 

extending to a maximum range of 20 km from the source were modeled using the MONM-BELLHOP 

acoustic propagation model. The same assumption about source heading was made for the side-scan 
Acoustic Modeling Report D-31 

sonar. The SLs were provided in rms SPL units; hence the output from the modeling was directly in 

terms of the rms SPL metric. 

3.2.8. Multibeam Depth Sounder 

For the purpose of modeling a representative multibeam depth sounder, the RESON SeaBat 7101 

model was selected as an example. This depth sounder uses the main working frequency of 240 kHz 

(RESON, 2009). The system utilizes a single beam transducer and multibeam receiver. The transducer 

head is mounted at the bottom of the ship’s hull. The projector beam width is 1.5° in the along-track 

direction and 170° in the across-track direction. The specifications of the depth sounder used for the 

modeling are presented in Table D-11. 

Table D-11 

 

Representative Multibeam Depth Sounder Specifications 

Main Operational Frequency 240 kHz 

Beam width along-track 1.5° 

Beam width across-track 170° 

rms SPL (dB re 1 μPa at 1 m) 210 

Peak level (dB re 1 μPa at 1 m) 213 

Pulse length 21–225 μs 

SEL (dB re 1 μPa2·s at 1 m) at 225 μs pulse length 173.5 

The beam patterns were again estimated using a mathematical model based on beam forming theory. 

Since the transducers are hull mounted, it was assumed that most of the acoustic energy is emitted in the 

downward half-space and that the upward component is negligible. 

Figure D-30 presents the calculated beam power function for the representative multibeam depth 

sounder at 240 kHz. Vertical slices of the beam pattern in along- and across-track directions are shown in 

Figure D-31. 

Figure D-30. Calculated Beam Pattern for the Representative Multibeam Depth 

Sounder at 240 kHz (beam power function shown relative to the onaxis level, using the Robinson projection). 
D-32 Atlantic G&G Programmatic EIS 

 

Figure D-31. Calculated Beam Pattern Vertical Slice for the Representative Multibeam Depth Sounder at 

240 kHz; (left) Along- and (right) Across-Track Directions. 

Modeling Approach 

The multibeam depth sounder was modeled at the single frequency of 240 kHz. The depth of the 

source was chosen to be 5 m. With a very narrow beam width, the variability of the emitted energy in 

different horizontal directions is very high. A circular fan of modeling radials with variable angular step 

(Table D-12) was created to a maximum range of 20 km from the source. The density of the radials was 

greater in proximity of the broadside, where beam variability is maximum, and lesser toward the endfire. 

The total number of rays modeled was 660. The source heading was again chosen for each modeling site 

considering the bathymetry at that location, with the assumption that the survey lines would run along the 

isobaths. The SL was provided in rms SPL units, hence the output from the modeling was directly in 

terms of the rms SPL metric. The depth sounder was modeled only at the sites designated for renewable 

energy development (water depth ~100 m). The source level for the sonar was chosen to be 210 dB re 

1 μPa. 

Table D-12 

 

Variable Angular Steps of the Modeling Radials in Different Sectors 

(only the steps for the first quadrant (0°-90°) are shown; those for the other quadrants were symmetrical) 

Sector Angular Step 

0° – 45° 1° 

45° – 80° 0.5° 

80° – 90° 0.2° 

4. MODELING METHODOLOGY 

Distinct modeling approaches were used for the low-frequency sources (airgun arrays) and mid- and 

high-frequency sources (electromechanical sources). 

The modeling of the underwater acoustic field resulting from the operation of a seismic array in a 

particular area involved the use of two complementary software codes. The AASM, described in 

Section 3.1.4, was used to predict the directional SL of a seismic airgun array. The MONM, an acoustic 
Acoustic Modeling Report D-33 

propagation model, was then used to estimate the acoustic field at any range from the source. Sound 

propagation modeling uses acoustic parameters appropriate for the specific geographic region of interest, 

including the water column sound speed profile, the bathymetry, and the bottom geoacoustic properties, 

to produce site-specific estimates of the radiated noise field as a function of range and depth. 

MONM-RAM, described in Section 4.1.1, was used to predict the directional TL footprint from various 

source locations corresponding to trial sites for experimental measurements. The RL at any 3D location 

away from the source is calculated by combining the SL and TL, both of which are direction dependent, 

using the fundamental relation  TLSLRL . Acoustic TL and RL are a function of depth, range, 

bearing, and environmental properties of the propagation medium. 

The RLs estimated by MONM, like the SLs from which they are computed, are expressed in terms of 

the so SEL metric over the duration of a single source pulse. Sound exposure level is expressed in units 

of dB re 1 μPa2 ·s. For the purposes of this study, the SEL results were converted to the rms SPL metric 

using a range dependent conversion coefficient (see Section 4.1.3). 

To model the sound field from the electromechanical sources a mathematical model 

(see Sections 2.2.1–3.24) was used to estimate the source beam pattern taking into account source 

specification data. The MONM-BELLHOP propagation code was then used to estimate the acoustic field 

around the source. Source beam pattern data as well as bathymetry, sediment geoacoustic properties, and 

water sound velocity profile information were provided as inputs for the propagation code. 

Once the unweighted acoustic fields were calculated, the M-weighting filters were applied to the 

fields to yield M-weighted acoustic fields. The application of the M-weighting filters was performed as 

outlined in Section 2.3.1 using Equation (6). 

4.1. SOUND PROPAGATION MODEL: MONM 

JASCO’s MONM was used for the sound field modeling of all the sources in this study, using two 

variants of the computational engine for handling different frequency ranges. The MONM computes 

acoustic fields in 3D by modeling TL along evenly spaced 2D radial traverses covering a 360° swath from 

the source, an approach commonly referred to as N×2D. The model fully accounts for depth and/or range 

dependence of several environmental parameters including bathymetry and sound speed profiles in the 

water column and the subbottom. The acoustic environment is sampled at a fixed range step along radial 

traverses. The acoustic propagation code estimates sound pressure levels at various horizontal distances 

from the source as well as at different depths. Depending on the input source sound level metric 

provided, MONM can compute received sound fields in SEL or rms SPL metrics. 

4.1.1. Low-Frequency – MONM-RAM 

For the acoustic sources in the low-frequency band (below 2 kHz) the MONM-RAM variant of the 

computational code was used. In this study the sources that operate in the low-frequency bands are the 

airgun array sources and the boomer. For the former, the directional SLs computed with AASM were 

input to MONM-RAM to determine the predicted RLs. 

The MONM-RAM treats sound propagation in range-varying acoustic environments through a 

wide-angled parabolic equation (PE) solution to the acoustic wave equation. The PE code used by 

MONM-RAM is based on a version of the Naval Research Laboratory’s RAM, which has been modified 

to account for an elastic seabed. The PE method has been extensively benchmarked and is widely 

employed in the underwater acoustics community (Collins et al., 1996). The MONM-RAM also accounts 

for the additional reflection loss at the seabed that is due to partial conversion of incident compressional 

waves to shear waves at the seabed and subbottom interfaces. It includes wave attenuations in all layers. 

The MONM-RAM treats frequency dependence by computing acoustic TL at the center frequencies 

of third-octave bands, between 10 Hz and 2 kHz in this study. Third-octave band RLs are computed by 

subtracting band TL values from the corresponding directional SLs. Broadband RLs are then computed 

by summing the received band levels. The MONM sound level predictions have been validated against 

experimental data in a formal study (Hannay and Racca, 2005) and in several instances where operational 

field measurements were obtained that allowed direct comparison to model estimates. 
D-34 Atlantic G&G Programmatic EIS 

4.1.2. Mid- and High-Frequency – MONM-BELLHOP 

For the acoustic sources in the mid- and high-frequency band (above 2 kHz), the MONM-BELLHOP 

variant of the computational code was used. In this study the sources that operate in the mid- and 

high-frequency bands are the boomer, side-scan sonar, chirp subbottom profiler, and multibeam depth 

sounder. 

The MONM-BELLHOP models sound propagation in range-varying acoustic environments using the 

BELLHOP acoustic ray trace model (Porter and Liu, 1994), which is based on the Gaussian beam tracing 

technique. In addition to other types of attenuation, MONM-BELLHOP accounts for sound attenuation 

due to energy absorption through ion relaxation and viscosity of water (Fisher and Simmons, 1977). This 

type of attenuation is significant for frequencies higher than 5 kHz and cannot be neglected without 

noticeable effect on the modeling results at longer distances from the source. 

The geoacoustic layering model for the MONM-BELLHOP propagation code consists of only one 

interface, namely the sea bottom. This is an acceptable limitation because the influence of the subbottom 

layers on the propagation of acoustic waves with frequencies above 2 kHz is negligible. 

The acoustic model takes into account the variability of the sound levels emitted in different 

directions from the source, referred to as source directivity. Source directivity is specified to the model as 

a function of both azimuthal and depression angle where azimuth is the horizontal direction relative to 

north and depression is the vertical angle relative to the horizontal plane. 

4.1.3. Estimating 90 Percent RMS SPL from SEL for Airgun Array Sources 

Existing U.S. safety radius regulations for impulsive sound sources are based on the rms SPL metric. 

An objective definition of pulse duration is needed when measuring the rms level for a pulse. Following 

suggestions by Malme et al. (1986), Greene (1997), and McCauley et al. (1998), pulse duration is 

conventionally taken to be the interval during which 90 percent of the pulse energy is received. Although 

the 90 percent rms SPL can be easily measured in situ, this metric is difficult to model in general because 

the adaptive integration period, implicit in the definition of the 90 percent rms level, is highly sensitive to 

the specific multipath arrival pattern from an acoustic source and can vary abruptly with distance from the 

source or with depth of the receiver. To accurately predict the 90 percent rms level, it is necessary to 

model full-waveform acoustic propagation, which in highly range dependent environments is 

computationally overwhelming for long range, large water depth (more than 1,000 m), and multiple 

profile models. 

Accurate estimates of airgun array safety ranges must take into account the acoustic energy that is 

returned to the water column by bottom and surface reflections. This is especially important in the case 

of shallow water conditions, which are found at many sites in the current study. If multipath reflections 

were taken into account, the resultant temporal spreading of the received seismic pulse would change the 

received pulse duration, rms estimates, and safety radii. The MONM algorithm does not attempt to 

predict the rms pressure directly; rather it models the propagation of acoustic energy in third-octave bands 

in a realistic, range-dependent acoustic environment. When these third-octave band levels are summed, 

the result is a broadband SEL, equivalent to the sound pressure level that would occur if the energy for a 

single airgun array pulse were spread evenly over a nominal time window of 1 s. 

From these predicted SEL values, the approximate rms equivalents can be obtained taking into 

account the interrelationships of SEL, rms SPL, and pulse duration as known from theory and from field 

studies where these parameters have all been measured for the same received airgun pulses. The rms SPL 

based on the 90 percent energy pulse duration is related to SEL via a simple function that depends only on 

the rms integration period T: 

SPLRMS90   T  458.0)log(10SEL (11) 

Here, the last term accounts for the fact that only 90 percent of the acoustic pulse energy is delivered 

over the standard integration period. In the absence of in situ measurements, the integration period is 

difficult to predict with any reasonable degree of accuracy. 

Two approaches can be used in this case. The first is to use a heuristic value of T, based on field 

measurements in similar environments, to estimate an rms SPL level from the modeled SEL. Safety radii 

estimated in this way are approximate since the true time spreading of the pulse has not actually been 

modeled. In various studies where the SPLRMS 90, SEL, and duration have been determined for individual 

airgun pulses, the average offset between SPL and SEL has been found to be 5–15 dB, with considerable 
Acoustic Modeling Report D-35 

variation dependent on water depth and geo-acoustic environment (Greene, 1997; McCauley et al., 2000; 

Blackwell et al., 2007; MacGillivray et al., 2007). On average, the measured SPL–SEL offsets tend to be 

larger at close distances, where the pulse duration is short (<<1 s), and to diminish at longer distances, 

where pulse duration tends to increase because of propagation effects. 

An alternative approach is to use a full-waveform acoustic propagation model to generate 

range-dependent estimates of SPL and SEL for a small set of representative transects, and then apply the 

SPL-SEL offsets obtained in this manner to the full MONM results. This approach combines the accurate 

pulse length information available from the full-waveform model with the greater computational 

efficiency of the MONM algorithm. For the conversion of the acoustic field in SEL metrics to rms SPL 

metrics, appropriate SPL–SEL range dependent functions are selected from the set of available 

representative transects on the basis of similarity of water depth and bottom type. 

For this study, a combination of the two approaches was chosen. The results of the full waveform 

estimation were combined with the data obtained during field measurements of similar sources in similar 

environments (e.g., Austin et al., 2003; Funk et al., 2008). Full-waveform results were derived for 

idealized flat bottom models with water depths of 40, 150, and 1,000 m. The bottom type was sand for 

the 40 and 150 m models and clay for the 1,000 m model. The estimated range dependent SPL–SEL 

offset functions used in this study are shown in Figure D-32. 

Figure D-32. SPL–SEL Conversion Functions for Different Water 

Depths. 

In applying the above conversions to the model results in this study, the sites with water depths from 

30 to 60 m were assigned the SPL–SEL function for 40 m depth, the sites with water depth from 

61 to 300 m the function for 150 m, and the sites deeper than 300 m the function for 1,000 m water depth. 

4.2. MODELING PROCEDURE

4.2.1. Area of Interest and Proposed Activities 

The AOI includes U.S. Atlantic waters from the mouth of Delaware Bay to just south of 

Cape Canaveral, Florida, and from the shoreline (excluding estuaries) to 648 km (350 nmi) from shore 

(Figure D-33). The total area of the AOI is 854,779 km2

 (330,032 mi2). The water depths inside the AOI 

vary from a few meters to more than 5,000 m, covering various types of oceanic bottom: continental 

shelf, continental slope and rise, and abyssal plain. 

Three major program areas of G&G activities are included in this study: 

 oil and gas exploration; 

 renewable energy development; and 

 marine minerals. 
D-36 Atlantic G&G Programmatic EIS 

Figure D-33. Area of Interest with the Locations of the Modeling Sites. 
Acoustic Modeling Report D-37 

Different activities would be performed in specific water depths. The types of acoustic sources are 

also defined by the type of planned activity (Table D-13). 

Table D-13 

 

List of Proposed G&G Activities and Sources 

Representative Modeling 

Activity Type Acoustic Source Water Depth 

(m) Acoustic Source 

Oil and Gas Exploration and Development (50–6,000 m) 

2D seismic survey Airgun array 

3,000–9,000 in3 50 – 6,000 Large airgun array 

5,400 in3

3D seismic survey Dual airgun array 

3,000–9,000 in3 50 – 6,000 Large airgun array 

5,400 in3

Vertical seismic profiling Airgun array 

1,000–6,000 in3 50 – 6,000 Large airgun array 

5,400 in3

High-resolution geophysical survey Single gun or airgun array 

45–200 in3 50 – 6,000 Small airgun array 

90 in3

Renewable Energy (0–100 m) 

Bathymetry data collection Multibeam depth sounder 100 Multibeam depth sounder 

Bottom obstruction detection Side-scan sonar 100 Side-scan sonar 

Shallow sediment mapping 

(0–100 mbsf) 

Shallow penetration 

subbottom profiler 100 Chirper 

Medium depth sediment mapping 

(0–200 mbsf) 

Medium penetration 

subbottom profiler 100 Boomer 

Marine Minerals (0–50 m) 

Bathymetry data collection Multibeam depth sounder 30 Multibeam depth sounder 

Bottom obstruction detection Side-scan sonar 30 Side-scan sonar 

Shallow sediment mapping 

(0–100 mbsf) 

Shallow penetration 

subbottom profiler 30 Chirper 

Medium depth sediment mapping 

(0–200 mbsf) 

Medium penetration 

subbottom profiler 30 Boomer 

Abbreviations: mbsf = meters below seafloor. 

Oil and gas explorations surveys could occur at water depths ranging from 50 m to more than 

4,000 m, covering all three bottom types – shelf, slope, and abyssal plain. The acoustic sources that 

would be utilized for these surveys include seismic airgun arrays of different types. The volume of air 

gun arrays may vary from less than 100 in3

 (high-resolution, geohazard seismic surveys) to more than 

5,000 in3

 (2D and 3D seismic surveys). 

Renewable energy development and marine mineral surveys would be limited to shallow waters with 

maximum water depth of about 100 m. The acoustic sources involved would include mid- to 

high-frequency electromechanical sources (boomers, chirp subbottom profilers, side-scan sonars, 

multibeam depth sounders, etc.). 

The information about the selected modeling sites is provided in Table D-14, and the map with the 

locations of these sites is shown in Figure D-33. 
D-38 Atlantic G&G Programmatic EIS 

Table D-14 

 

Modeling Site Information 

Geographic 

Coordinates UTM Coordinates Site 

Number North West Northing Easting Zone 

Bottom 

Type 

Water 

Depth at 

the Source

(m) 

Towing 

Azimuth 

1 32.00 -72.00 3544000 783000 18 Clay 5,390 N/A 

2 32.75 -76.00 3624000 406000 18 Clay 2,560 N/A 

3 31.00 -78.00 3433000 214000 18 Sand 880 N/A 

4 30.48 -80.09 3373000 588000 17 Sand 249 N/A

5 36.25 -74.77 4012000 520000 18 Sand 288 N/A

6 31.50 -75.00 3485000 500000 18 Clay 3,200 N/A

7 31.85 -79.16 3526000 674000 17 Sand 251 N/A

8 34.59 -75.63 3828000 443000 18 Sand 249 N/A

9 36.00 -74.79 3984000 519000 18 Sand 275 N/A

10 36.50 -71.00 4041000 321000 19 Clay 4,300 N/A

11 36.84 -73.31 4079000 651000 18 Clay 3,010 N/A

12 29.50 -75.50 3263000 452000 18 Clay 4,890 N/A

13 31.00 -75.50 3430000 452000 18 Clay 3,580 N/A

14 32.00 -79.25 3542000 665000 17 Sand 100 N/A

15 36.51 -74.82 4040000 516000 18 Sand 51 N/A

16 36.16 -75.24 4001808 478773 18 Sand 30 N/A

17 36.09 -74.84 3993702 514548 18 Sand 100 10° 

18 34.80 -75.89 3851633 418959 18 Sand 30 40° 

19 34.70 -75.63 3840310 442218 18 Sand 100 40° 

20 32.30 -79.52 3574265 639795 17 Sand 30 35° 

21 30.55 -80.64 3380052 534518 17 Sand 30 20° 

22 30.49 -80.16 3372884 580545 17 Sand 100 20° 

N/A = not applicable. Towing azimuth not needed for calculations because the seafloor is flat. 

4.2.2. Model Profiles 

Both acoustic propagation models, MONM-RAM and MONM-BELLHOP, compute acoustic fields 

along one 2D radial traverse at a time. One can obtain a 3D distribution of the acoustic field around a 

source by combining a set of radial traverses covering a 360° swath from the source. The angular step 

between the radials can be either constant or variable, depending on the type of source and its horizontal 

directivity function. This approach commonly is referred to as N×2D. 

Assuming that the bottom geoacoustic properties and the water column are uniform in all directions 

from a given modeling site, the parameters that change from profile to profile are the bathymetry and the 

SL for a directional source. For an omnidirectional source, the only parameter that would change 

between profiles is the bathymetry. 

For the purpose of this study, an adaptive approach was taken for defining the distribution of 

modeling profiles. For the boomer and airgun array sources, the profiles were evenly spaced around the 

source; the number of profiles, however, depended on the water depth observed inside the modeling area, 

varied from 120 (3° step) to 24 (15° step). Also for the very deep sites (water depth more than 3,000 m), 

only one profile was modeled and then cloned 24 times along the fan of radials. This approach was 

considered readily justifiable since the bathymetry, which is the only parameter that would change from 

profile to profile, is virtually flat at deep sites and at such depths has very little influence on the sound 

propagation. The angular step and the total number of profiles modeled at different sites for the boomer 

and airgun arrays sources are provided in Table D-15. 
Acoustic Modeling Report D-39 

Table D-15 

 

Modeling Profile Information for Airgun Array Sources at Different Sites 

Site Number 

Water Depth 

at the Source 

(m) 

Number of Profiles Angular Step 

Maximum 

Receiver Depth 

(m) 

1 5,390 1 – 2,000 

2 2,560 24 15° 2,000 

3 880 120 3° 1,000 

4 249 120 3° 500 

5 288 72 5° 2,000 

6 3,200 1 – 2,000 

7 251 120 3° 600 

8 249 72 5° 2,000 

9 275 72 5° 2,000 

10 4,300 1 – 2,000 

11 3,010 1 – 2,000 

12 4,890 1 – 2,000 

13 3,580 1 – 2,000 

14 100 120 3° 650 

15 51 72 5° 2,000 

16 30 72 5° 40 

17 100 72 5° 200 

18 30 72 5° 50 

19 100 72 5° 1,000 

20 30 72 5° 50 

21 30 72 5° 40 

22 100 72 5° 500 

The angular step size for the high-frequency sources was chosen based on the minimum beam width 

and the directivity pattern. The minimum angular step size was chosen to be no more than half the size of 

the beam width. The modeling profiles information for the engineering source, except the boomer is 

provided in Table D-16. The same profile pattern was used for all sites where these sources were 

modeled, namely locations 16-22. The water depth at the source and the maximum receiver depth are the 

same as shown in Table D-15. 

Table D-16 

 

Modeling Profile Information for Electromechanical Sources Except the Boomer 

Source Smallest Beam Width Number of Profiles Angular Step Size 

Side-scan sonar 0.4° 660 Variable: 0.2°–1° 

Chirp subbottom profiler 8° 72 Constant: 5° 

Multibeam depth sounder 1° 309 Variable: 0.5°–2° 

4.2.3. Model Receiver Depths 

Model receiver depths are the depths below the water surface at which virtual receivers are placed in 

the acoustic propagation model and the TL is sampled. From the chosen source positions, the model can 

generate a grid of predicted acoustic levels over any desired area, as well as at any depth in the water 

column. The virtual receivers can, in principle, be placed at a vertical step size as fine as the acoustic 
D-40 Atlantic G&G Programmatic EIS 

field modeling grid, which varies from 2 m for low frequencies to 6 cm for high frequencies. Such a fine 

grid of receivers, however, would be very inefficient and provide too large a quantity of data. The depth 

spacing between the receiver planes was therefore chosen on the basis of the vertical variability of the 

acoustic field, which in turn depends on the variability of the sound speed profile – higher at the top of the 

water column, lower at greater depths. The maximum depth for the virtual receivers (2,000 m) was 

chosen based on the normal dive depth limits for the marine mammals in the AOI. 

The set of virtual receivers depths for the sites designated for oil and gas exploration (water depth 

from 50 to 5,390 m) was as follows: 2, 5, 10, 15, 20, 25, 50, 75, 100, 150, 200, 250, 300, 350, 400, 500, 

550, 600, 650, 700, 750, 800, 850, 900, 950, 1,000, 1,100, 1,200, 1,400, 1,600, 1,800, and 2,000 m. 

For the sites where electromechanical sources were modeled (water depths at the source 30 and 

100 m) several depths were added at the top of the water column. The set of virtual receiver depths for 

the sites designated for marine minerals and renewable energy development (sites 16–22) was as follows: 

2, 5, 7.5, 10, 12.5, 15, 17.5, 20, 22.5, 25, 27.5, 30, 35, 40, 45, 50, 75, 100, 150, 200, 250, 300, 350, 400, 

500, 550, 600, 650, 700, 750, 800, 850, 900, 950, and 1,000 m. 

4.2.4. Model Radial Step Size 

The quality of the modeling results is highly dependent on the radial step size, as with too large a step 

the modeling approximation can become unstable and produce inaccurate results. For the purpose of this 

study, the radial modeling step size was set at a very finely resolved 5 m. Further reduction of the step 

size provides virtually no quality benefit for the results while increasing the computational requirements. 

Before transferring the modeled acoustic field data for use with the Acoustic Integration Model (AIM) 

individual-based exposure model, however, the radial results were downsampled with a variable step size 

in order to increase the efficiency of the data processing. The set of distances from the source in meters at 

which the received acoustic field was reported for use in AIM was generated according to the following 

equation: 

2 r  i , where i=1,2,3,...,141 (12) 

4.3. BATHYMETRY AND ACOUSTIC PARAMETERS

4.3.1. Bathymetry 

The bathymetry data for this project was provided by CSA International, Inc. The bathymetry grid 

spans from 28° N to 40° N and from 66.5° W to 82.5° W, fully covering the AOI. The resolution of the 

grid is about 1.5 arc seconds or approximately 50 m. 

For the purpose of modeling, smaller portions of the large grid were extracted for each modeling site. 

The overall bathymetry information was considered from the start in choosing the locations for the 

modeling sites, both in terms of selecting locations with desired water depths and of avoiding areas with 

highly site-specific bathymetry features such as localized sea bottom rises or depressions. 

4.3.2. Geoacoustic Properties 

In view of the generalized nature of this study, a more generic approach to the definition of 

geoacoustic properties was exercised than would normally be used for site specific modeling. The AOI 

spans numerous geological provinces with highly variable stratification profiles. It would not have been 

opportune to consider site specific geoacoustic profiles, since the acoustic modeling results thus obtained 

would introduce excessive bias when used as estimation for other locations. Generic geoacoustic profiles 

were created instead, which only take into account the type of sediment found at the sea bottom with the 

appropriate porosity value and typical porosity trend with depth below the seafloor (which is sediment 

type specific). Any layered model of the sediment column was avoided, i.e. there were no interfaces in 

the geoacoustic profiles at which a rapid change of properties is observed because of sediment type 

transition. Instead, only a gradual change of properties with depth was introduced. 

The acoustic properties of sediment layers that are required by MONM are density (), compressional 

speed (Vp), compressional attenuation coefficient in decibels per wavelength (αp), shear wave speed (Vs), 

and shear wave attenuation coefficient (αs), also in decibels per wavelength. These geoacoustic 

parameters were estimated using a sediment grain-shearing model (Buckingham, 2005), which computes 

the acoustic properties of the sediments from porosity and grain-size measurements. The input parameters 
Acoustic Modeling Report D-41 

required by the geoacoustic model were the bottom type (grain size) and sediment porosity, inferred from 

the geological description of the modeling region. 

Numerous surficial sediment-type data exist for the Atlantic region off-shore U.S. coast, for example 

the U.S. Geological Survey (USGS) Continental Margin Program (Hathaway, 1977) and the National 

Geophysical Data Center (NGDC) Seafloor Sediment Descriptions (Bershad and Weiss, 1975). Poppe et 

al. (1989) provided a map of distribution of the surficial sediments for the region. According to the map, 

the surficial sediments over 85 percent of the area of interest are represented either by sand or clay. The 

remaining 15 percent of the area is characterized by transitional sediment types. 

The distribution of the specific type of sediment is primarily determined by the bathymetry. 

Sediments that can be described as sand are found at water depths from 0 to 1,000 m. In deeper 

environment, the prevailing sediment type is clay, which is found at water depths 900 m and greater. 

Clay 

The geoacoustic profile for clay sediments was constructed based on the data obtained by the Ocean 

Drilling Program (ODP) at site 905, leg 150 (Shipboard Scientific Party, 1994). The well was located at a 

water depth of 2,700 m. The reported porosity for the surficial sediments was 60 percent and did not 

change with depth, maintaining the same value of 60 percent down to 600 m below the seafloor. The 

geoacoustic model for clay sediments is presented in Table D-17. 

Table D-17 

 

Geoacoustic Model for the Clay Sediments 

Depth 

(m) 

ρ

(g/cm3

) 

Vp

(m/s) 

αp

(dB/λ) 

Vs

(m/s) 

αs

(dB/λ) 

0–10 1.70 1,563–1,613 0.19–0.40 

10–50 1.70 1,613–1,683 0.40–0.67 

50–150 1.70 1,683–1,763 0.67–0.93 

150–300 1.70 1,763–1,833 0.93–1.14 

300–600 1.70 1,833–1,925 1.14–1.37 

>600 1.70 1,925 1.37 

61 0.01 

Sand 

The geoacoustic profile for sand sediments was constructed based on the data obtained by the ODP at 

site 1071, leg 174 (Shipboard Scientific Party, 1998). The well was located at a water depth of 100 m. 

The reported porosity for the surficial sediments was 50 percent and decreased gradually decreasing with 

depth below the seafloor; at 150 m below the seafloor the porosity reached 40 percent and did not change 

for greater depths. The geoacoustic model for sand sediments is presented in Table D-18. 

Table D-18 

 

Geoacoustic Model for the Sand Sediments 

Depth 

(m) 

ρ

(g/cm3

) 

Vp

(m/s) 

αp

(dB/λ) 

Vs

(m/s) 

αs

(dB/λ) 

0–10 1.87 1,648–1,785 0.45–0.92 

10–50 1.87 1,785–1,987 0.92–1.45 

50–150 1.87–2.04 1,987–,2276 1.45–1.79 

150–300 2.04 2,276–2,482 1.79–2.08 

300–600 2.04 2,482 2.08 

158 0.07 
D-42 Atlantic G&G Programmatic EIS 

4.3.3. Sound Speed Profiles 

The vertical sound speed profiles used in this modeling study were provided by Marine Acoustics, 

Inc. (MAI). The selected profiles were to reflect the variation of the sea water properties at different 

locations throughout the AOI as well as seasonal variation at the same location. They represent various 

types of sound propagation through the water layer such as ducted propagation, presence of convergence 

zone, and bottom bounce propagation. 

As indicated by MAI, the data for the computation of the sound velocity in the water column were 

mined from the U.S. Naval Oceanographic Office’s Generalized Digital Environmental Model (GDEM) 

database (Teague et al., 1990). The GDEM database provides average monthly profiles of temperature 

and salinity for the world’s oceans on a latitude-longitude grid with 0.25-degree resolution. Profiles in 

GDEM are provided at 78 fixed-depth points up to a maximum depth of 6,800 m. The profiles in GDEM 

are based on historical observations of global temperature and salinity from the U.S. Navy’s Master 

Oceanographic Observational Data Set (MOODS). The GDEM provides historical average profiles that 

extend to the maximum depth in a given 15-arc-minute square. The parameters for the sound speed 

profiles used in this study are shown in Table D-19. The sound speed profiles for the winter, spring, 

summer, and fall seasons are shown in Figures D-34 through D-37, respectively. 

Table D-19 

 

List of Sound Speed Profiles Used in This Study 

Profile Number Season Propagation Characteristic Representative Location 

1 Winter Convergence zone (deep water) 

Bottom bounce (mid-range water depth) 32°45’N 72°00’W 

2 Winter Shallow water 30°30’N 74°45’W 

3 Winter Shallow water 36°15’N 80°15’W 

4 Spring Convergence zone (deep water) 

Bottom bounce (mid-range water depth) 31°30’N 75°00’W 

5 Spring Bottom bounce (shallow water) 32°00’N 79°15’W 

6 Spring Moderately ducted (shallow water) 35°00’N 76°15’W 

7 Summer Convergence zone (deep water) 

Bottom bounce (mid-range water depth) 31°30’N 75°00’W 

8 Summer Shallow water 36°00’N 74°45’W 

9 Fall Convergence zone (deep water) 36°30’N 71°30’W 

10 Fall Convergence zone (deep water) 

Bottom bounce (mid-range water depth) 31°00’N 78°00’W 

11 Fall Shallow water 32°00’N 79°15’W 

12 Fall Shallow water 36°30’N 74°45’W 
Acoustic Modeling Report D-43 

Figure D-34. Sound Velocity Profiles for Winter Season Used in This Modeling Study: Fully Extended to the 

Maximum Depth (left) and Zoomed-in Upper Portion (right). 

Figure D-35. Sound Velocity Profiles for Spring Season Used in This Modeling Study: Fully Extended to the 

Maximum Depth (left) and Zoomed-in Upper Portion (right). 
D-44 Atlantic G&G Programmatic EIS 

Figure D-36. Sound Velocity Profiles for Summer Seasons Used in This Modeling Study: Fully Extended to the 

Maximum Depth (left) and Zoomed-in Upper Portion (right). 

Figure D-37. Sound Velocity Profiles for Fall Season Used in This Modeling Study: Fully Extended to the 

Maximum Depth (left) and Zoomed-in Upper Portion (right). 
Acoustic Modeling Report D-45 

4.4. MODELING SCENARIOS

A total of 22 modeling sites was identified in various parts of the AOI (Table D-14 and 

Figure D-33). For each site, modeling was done using 1-4 different sound velocity profiles (Table D-19

and Figures D-34 through D-37), for a total of 35 modeling scenarios. The geoacoustic model also 

varied from site to site. Scenarios from 1 to 21 were designated for modeling oil and gas exploration 

activities using airgun array sources. Scenarios 22-35 were modeled for marine minerals and renewable 

energy development using the boomer, side-scan sonar, chirp subbottom profiler, and multibeam depth 

sounder. 

The complete list of scenarios modeled in this study together with indication of the sources that were 

modeled for each scenario is provided in Table D-20. There were a total of 105 combinations of 

scenarios and sources. For each combination, an acoustic field was modeled and threshold distances to 

the specified rms SPL value were calculated. Each acoustic field was also downsampled as previously 

described and provided as an input for exposure modeling with the AIM software. 

4.5. CLASSIFICATION OF ACOUSTIC ENVIRONMENTS

Each acoustic modeling scenario is characterized by a unique combination of parameters. The main 

variables in the environment configuration are the bathymetry and the sound velocity profile in the water 

column. The geoacoustic properties of the sea bottom are directly correlated with the water depth of the 

modeling site. The major factor that affects sound propagation in different areas throughout the AOI is 

the water depth. Four regions can be classified based on the bathymetry: 

 shallow continental shelf (<60 m); 

 continental shelf (60–150 m); 

 continental slope (150–1,000 m); and 

 deep ocean (>1,000 m). 

Each region exhibits a specific acoustic propagation regime, which will be discussed in following 

sections and exemplified graphically using frequency versus distance plots. These are useful tools for 

analysis of the acoustic propagation environment, as they help to understand how the physical conditions, 

mostly water depth, affect propagation of the acoustic waves at different frequencies. 

4.5.1. Shallow Continental Shelf 

Shallow continental shelf is defined as the areas with depth less than 60 m. Modeling sites that fall 

into this region are 15, 16, 18, 20, and 21. The bottom type for this area is sand and the bottom sloping is 

minimal, usually less than 0.1°. Inside each modeling area (20 km radius) the variability in depth is less 

than 5 m; such a small variation in bathymetry has virtually no effect on the sound propagation in 

different directions from the source except for some local features of the sea bottom. 

An example of frequency versus distance plot for Scenario 22 (Site 16) is provided in Figure D-38. 

The shallow environment does not favor the propagation of low frequencies as the mode propagation 

condition cannot be established for the acoustic waves at these frequencies. The TL for frequencies lower 

than 20 Hz is significantly greater than for higher frequencies. Acoustic waves with frequencies between 

20 and 80 Hz also experience higher attenuation due to shallow environment. 

The vertical sound speed profile in the water column has very little influence on the propagation of 

the sound in shallow waters, as the variation in sound velocity is not significant in the top 30 m of the 

profile. The geometric spreading of the acoustic wave energy transitions from spherical-spreading into a 

cylindrical-spreading regime very close to the source. A highly reflective bottom interface ensures that 

most of the acoustic energy is returned into the water column after interaction with the seafloor, and 

bottom reflections contribute significantly to the total acoustic field. 
D-46 Atlantic G&G Programmatic EIS 

Table D-20 

 

List of Modeling Scenarios 

Modeled Sources 

Scenario 

Number 

Site 

Number 

Water 

Depth 

(m) 

Season Sound 

Profile 

Bottom 

Type 5,400 in3

Airgun 

Array 

90 in3

Airgun 

Array 

Boomer, 

SSS, SBP MBE 

1 1 5,390 Winter SVP 01 Clay X X 

2 2 2,560 Winter SVP 01 Clay X X 

3 3 880 Winter SVP 01 Sand X X 

4 4 249 Winter SVP 02 Sand X X 

5 5 288 Winter SVP 03 Sand X X 

6 1 5,390 Spring SVP 04 Clay X X 

7 6 3,200 Spring SVP 04 Clay X X 

8 3 8,80 Spring SVP 04 Sand X X 

9 7 251 Spring SVP 05 Sand X X 

10 8 249 Spring SVP 06 Sand X X 

11 1 5,390 Summer SVP 07 Clay X X 

12 6 3,200 Summer SVP 07 Clay X X 

13 3 880 Summer SVP 07 Sand X X 

14 9 275 Summer SVP 08 Sand X X 

15 10 4,300 Fall SVP 09 Clay X X 

16 11 3,010 Fall SVP 09 Clay X X 

17 12 4,890 Fall SVP 10 Clay X X 

18 13 3,580 Fall SVP 10 Clay X X 

19 3 880 Fall SVP 10 Sand X X 

20 14 100 Fall SVP 11 Sand X X 

21 15 51 Fall SVP 12 Sand X X 

22 16 30 Spring SVP 03 Sand X 

23 17 100 Spring SVP 03 Sand X X 

24 16 30 Summer SVP 08 Sand X 

25 17 100 Summer SVP 08 Sand X X 

26 16 30 Fall SVP 12 Sand X 

27 17 100 Fall SVP 12 Sand X X 

28 18 30 Spring SVP 06 Sand X 

29 19 100 Spring SVP 06 Sand X X 

30 20 30 Spring SVP 05 Sand X 

31 14 100 Spring SVP 05 Sand X X 

32 20 30 Fall SVP 11 Sand X 

33 14 100 Fall SVP 11 Sand X X 

34 21 30 Winter SVP 02 Sand X 

35 22 100 Winter SVP 02 Sand X X 

Abbreviations: MBE = multibeam depth sounder; SBE = chirp subbottom profiler; SSS = side-scan sonar. 
Acoustic Modeling Report D-47 

Figure D-38. Frequency Versus Distance Plot Based on Modeled Data for Scenario 22 

(SVP 03) (water depth at the source is 30 m). 

4.5.2. Continental Shelf 

For the purpose of this work, continental shelf is defined as the areas with water depth less than 

150 m with the exclusion of areas defined as shallow continental shelf in Section 4.5.1. Modeling site 

numbers that fall into this region are 14, 17, 19, and 22. The bottom type for this area is sand and the 

bottom sloping is more pronounced than in the shallow continental area, with a slope varying from 

0.5° to 1° and a bathymetry condition that can be no longer be considered flat. With a water depth at the 

source of 100 m, the depth inside the modeling area (20 km radius) can vary from 40 m to as deep as 

1,500 m. 

An example of frequency versus distance plot for Scenario 23 (Site 17) is provided in Figure D-39. 

With greater water depth than in the shallow continental shelf environment, all modeled frequencies can 

effectively propagate through the water layer waveguide; very low frequencies (10–15 Hz), however, still 

experience elevated TL compared with the higher frequencies. 

Figure D-39. Frequency Versus Distance Plot Based on Modeled Data for Scenario 23 

(SVP 03) (water depth at the source is 100 m). 

The vertical sound speed profile in the water column influences the propagation of the sound in the 

area. Most of the sound speed profiles used in the modeling scenarios feature negative velocity gradient 

at a depth of 30 m below the sea surface. Negative velocity gradient refracts the acoustic wave 

downwards and directs it into the seafloor, increasing the effect of bottom loss. The TL for high 

frequencies (100–2,000 Hz) is greater compared to the shallow continental shelf regions. 
D-48 Atlantic G&G Programmatic EIS 

The geometric spreading of the acoustic wave energy still transitions into cylindrical spreading 

regime very close to the source. A highly reflective bottom interface ensures that most of the acoustic 

energy is returned into the water column after interaction with the seafloor, and bottom reflections 

contribute significantly to the total acoustic field. 

4.5.3. Continental Slope 

For the purpose of this work, continental slope is defined as the areas with water depth between 

150 and 1,000 m. Modeling site numbers that fall into this category are 3, 4, 5, 7, 8, and 9. The bottom 

type for this area is sand and the bottom inclination is significant, reaching values as high as 13°. With a 

water depth at the source between 250 and 900 m, the depth inside the modeling area (20 km radius) can 

vary from 40 m to as deep as 2,500 m. 

Two examples of frequency versus distance plot for Scenario 14 (Site 9) and for Scenario 3 (Site 3) 

are provided in Figures D-40 and D-41, respectively. With greater water depth than in continental shelf 

environment, all modeled frequencies can effectively propagate through the water layer waveguide. Low 

frequencies (10–100 Hz), however, can still experience elevated TL for a shallow location of the source. 

The sound speed profile in the water column influences the propagation of the sound in the area. 

Most of the sound speed profiles used in the modeling scenarios feature negative velocity gradient from 

30 m to about 1,200 m below the sea surface. Negative velocity gradient refracts the acoustic wave 

downward and directs it into the seafloor, increasing the effect of the bottom loss. The TL for high 

frequencies (100–2,000 Hz) is greater compared to the shallow continental shelf regions. 

The geometric spreading of the acoustic wave energy transitions into a cylindrical-spreading regime 

at about 250 m or farther from the source. A highly reflective bottom interface ensures that most of the 

acoustic energy is returned into the water column after interaction with the seafloor, and bottom 

reflections contribute significantly to the total acoustic field near the source; their contribution, however, 

diminishes for greater water depths at the source. 

Figure D-40. Frequency Versus Distance Plot Based on Modeled Data for Scenario 14 

(SVP 08) (water depth at the source is 250 m). 
Acoustic Modeling Report D-49 

Figure D-41. Frequency Versus Distance Plot Based on Modeled Data for Scenario 3 

(SVP 01) (water depth at the source is 880 m). 

4.5.4. Deep Ocean 

For the purpose of this work, deep ocean is defined as the areas with water depth greater than 

1,000 m. Modeling site numbers that fall into this category are 1, 2, 6, and 10–13. The bottom type for 

this area is clay; bottom sloping can be significant near the continental slope regions and almost absent at 

depths greater than 2,000 m. The relative variation of the water depth inside a modeling area (radius 

20 km) is small. 

An example of frequency versus distance plot for Scenario 1 (Site 1) is provided in Figure D-42. 

With larger water depths, all modeled frequencies can effectively propagate through the water layer 

waveguide. However, low frequencies (10–100 Hz) can still experience elevated TL for a shallow 

location of the source. 

Figure D-42. Frequency Versus Distance Plot Based on Modeled Data for Scenario 1 

(SVP 01) (water depth at the source is 5,390 m). 

The vertical sound speed profile in the water column has significant effect on the propagation of the 

sound in the area. All sound speed profiles used in the modeling scenarios feature a deep sound channel 

at about 1,200–1,300 m below the surface. Positive velocity gradient refracts the acoustic wave upwards 

and directs it away from the bottom, decreasing the effect of the bottom loss. Also, shadow zones can be 

established in the water volume because of refraction. At the sites with water depths greater than 4,000 m 

a ray convergence effect can be observed; such a phenomenon can, over small volumes, lower the TL to 

as little as 60 dB at distances of 130 km. 
D-50 Atlantic G&G Programmatic EIS 

Spherical spreading of the acoustic wave energy can persists as far as 5,000 m from the emitter 

(a range equal to the water depth at the source). Since the reflection coefficient of the clay bottom is low, 

most of the waterborne acoustic energy reaching the sediment layer experiences substantial loss. There is 

no significant contribution from bottom reflections to the total acoustic field near the source because of 

the large difference in travel distance between the direct and reflected wave. 

5. MODEL RESULTS 

The sound propagation code was run in the full N2D scheme as described in Section 4.1.1 for each 

of the 35 model scenarios and corresponding acoustic sources for a total of 105 combinations of sources 

and scenarios. The model estimates of received SEL for the airgun array sources were converted to rms 

SPL as outlined in Section 4.1.3. 

To produce single maps of received sound level distribution and to calculate threshold distances to 

specified levels, the maximum level over all modeled receiver depths was calculated at each horizontal 

point of the modeling regions. The radial grid of modeled profiles was then resampled to produce a 

regular Cartesian grid with a cell size of 5 m. All contours and threshold ranges were calculated from 

these flat Cartesian projections of the estimated acoustic fields. The sound level maps, grouped by 

scenarios, are provided in Attachment A, Figures Attachment A-1 through A-35. 

For each sound level threshold, two different statistical estimates of the safety radii are provided in 

the tables in Attachment B: the maximum range and the 95 percent range. Given a regularly gridded

spatial distribution of modeled RLs, the 95 percent range is defined as the radius of a circle that 

encompasses 95 percent of the grid points whose value is equal to or greater than the threshold value. 

This definition is meaningful in terms of potential impact to an animal because, regardless of the 

geometrical shape of the noise footprint for a given threshold level, it always provides a range beyond 

which no more than 5 percent of a uniformly distributed population would be exposed to sound at or 

above that level. The maximum range, which is simply the distance to the farthest occurrence of the 

threshold level, is the more conservative but may misrepresent the effective exposure zone. Indeed, there 

are cases where the volume ensonified to a specific level may not be continuous and small pockets of 

higher RLs may be found far outside the main ensonified volume (for example, because of convergence). 

If only the maximum range is presented, a false impression of the extent of the acoustic field can be 

given. 

Tables D-21 and D-22 summarize the results of the acoustic modeling in terms of threshold radii to 

the 160 dB and 180 dB rms SPL for the airgun arrays and electromechanical sources respectively. The 

complete sets of predicted threshold radii for each source to levels from 210 dB down to 150 dB rms SPL 

in 10 dB steps are presented in Attachment B, Table Attachment B-1 through Table Attachment B-6. 

From the tabulated results, it can be seen that the largest threshold radii for the airgun array sources 

are typically associated with sites in intermediate water depths (250 and 900 m); this is especially 

applicable to the 160 dB level. As noted above, low frequencies propagate relatively poorly in shallow 

water (i.e., water depths on the same order as or less than the wavelength). At intermediate water depths, 

this stripping of low-frequency sound no longer occurs, and longer-range propagation can be enhanced by 

the channeling of sound caused by reflection from the surface and seafloor (depending on the nature of 

the sound speed profile and sediment type). 

The modeling results for the radii for the specific threshold levels presented in Table D-22 do not 

account for the difference between the length of the pulse emitted by the acoustic instrument and the 

minimum integration time of the mammalian hearing apparatus. Instead, a receiver with unlimited 

minimum integration time was considered in the calculations. The calculation of rms SPL depends on the 

integration time (see Equation [1]). The application of the appropriate minimum integration time 

assumed for the marine mammals can significantly decrease the received rms SPL levels and, 

consequently, the threshold radii. The adjustment of the received rms SPL for the different integration 

time can be calculated with Equation [7]. Table D-23 provides the adjustment values for the 

representative electromechanical sources with their respective pulse durations and the assumed minimum 

integration time of 100 ms. 
Acoustic Modeling Report D-51 

Table D-21 

 

Summary of the Predicted Threshold Radii (in meters) for the 180 and 160 dB SPL (rms) for Airgun Array Sources 

Source Airgun Array 5,400 in3 Airgun Array 90 in3

dB SPL 180 160 180 160 

Scenario Rmax R95% Rmax R95% Rmax R95% Rmax R95%

1 835 810 5,379 4,969 148 144 1,295 1,256 

2 876 827 5,720 5,184 148 143 1,363 1,291 

3 1,557 1,093 9,329 8,104 148 145 2,210 2,038 

4 822 748 12,737 8,725 76 75 1,452 1,342 

5 816 742 13,337 8,896 76 74 1,568 1,286 

6 837 811 5,379 4,989 148 144 1,295 1,256 

7 855 829 5,322 5,026 146 142 1,322 1,281 

8 1,556 1,091 9,654 8,056 148 145 2,212 2,039 

9 801 737 11,056 8,593 76 74 1,464 1,331 

10 799 752 11,695 8,615 76 75 1,512 1,108 

11 837 811 5,379 4,973 146 143 1,295 1,255 

12 853 827 5,320 5,013 146 141 1,321 1,280 

13 1,552 1,082 9,316 8,095 147 143 2,211 2,036 

14 880 761 15,305 9,122 76 74 1,371 1,100 

15 841 816 5,490 5,121 146 143 1,315 1,258 

16 871 846 5,360 5,098 149 145 1,325 1,285 

17 838 812 5,184 4,959 149 145 1,294 1,255 

18 845 819 5,450 5,069 148 145 1,329 1,289 

19 1,559 1,094 9,304 8,083 149 145 2,212 2,040 

20 1,134 992 12,022 8,531 90 86 2,051 1,681 

21 2,109 1,677 11,380 8,384 186 177 3,056 2,493 

Table D-22 

 

Summary of the Predicted Threshold Radii (in meters) for 180 and 160 dB SPL (rms) for Electromechanical Sources 

Source: Boomer Side-Scan Sonar Chirp Subbottom 

Profiler 

Multibeam Depth 

Sounder 

dB SPL 180 160 180 160 180 160 180 160 

Scenario Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95%

22 43 43 1,737 1,490 192 180 604 534 32 28 808 682 -- -- -- -- 

23 39 38 1,060 818 128 116 512 440 38 35 380 303 27 25 147 142 

24 43 42 1,956 1,444 186 176 602 532 32 28 874 772 -- -- -- -- 

25 38 36 1,566 1,342 138 116 532 455 37 35 376 317 27 25 147 142 

26 43 41 1,712 1,428 190 176 600 530 32 28 764 664 -- -- -- -- 

27 40 40 1,054 807 128 116 500 438 37 35 359 297 27 25 147 142 

28 41 40 1,860 1,468 177 156 655 528 33 29 971 876 -- -- -- -- 

29 39 38 1,129 799 133 125 650 499 42 37 854 677 27 25 156 149 

30 43 41 1,730 1,435 171 154 576 510 33 29 831 644 -- -- -- -- 

31 40 39 1,155 840 129 115 537 462 42 39 557 313 27 25 147 140 

32 45 43 2,138 1,552 178 156 600 539 33 29 962 811 -- -- -- -- 

33 39 38 1,655 898 132 119 567 492 42 39 684 363 27 25 147 140 

34 43 43 1,844 1,467 175 159 592 526 32 29 724 634 -- -- -- -- 

35 40 38 1,035 669 134 121 538 458 42 38 401 300 27 25 149 144 
D-52 Atlantic G&G Programmatic EIS 

Table D-23 

 

Adjustment of the 180-dB and 160-dB Threshold Radii Based on the Difference between the Pulse Length of the 

Electromechanical Sources and the Minimum Integration Time of the Mammalian Hearing Apparatus (100 ms) 

Adjusted Radius (m) 

Source Pulse 

Length 

Adjustment 

Value (dB) 180 dB 

(Rmax) 

160 dB 

(Rmax) 

Operating Frequency 

within Cetacean 

Hearing Range? 

Boomer 180 μs -27.3 <5 16 Yes (0.2-16 kHz) 

Side-scan sonar 20 ms -7.0 65-96 337-450 Yes (100 kHz) 

No (400 kHz) 

Chirp subbottom profiler 64 ms -1.9 26-35 240-689 Yes (3.5 kHz, 12 kHz)

No (200 kHz) 

Multibeam depth sounder 225 μs -26.5 <5 12 No (240 kHz) 

Adjustment for the minimum integration time is only applicable to the electromechanical sources for 

which pulse length is shorter than the specific minimum integration time. The modeling results for the 

airgun array sources are not subject to adjustment as the length of the acoustic pulse from such sources is 

usually greater than 100 ms, i.e., longer than the minimum integration time of the mammalian hearing 

apparatus. 

The relatively small effect range for multibeam depth sounders is consistent with a recent analysis by 

Lurton and DeRuiter (2011) taking into account both the short pulse duration and high directivity of the 

source. 

Operating frequency is another consideration in defining an appropriate safety zone. While airguns 

and boomers produce sounds within the hearing range of cetaceans, the operating frequency of the 

representative multibeam system (240 kHz) is above the hearing range of all cetaceans. For side-scan 

sonar, the 100 kHz operating frequency is within the cetacean hearing range but the 400 kHz frequency is 

not. For the chirp subbottom profiler, the 3.5 and 12 kHz frequencies are within the cetacean hearing 

range but the 200 kHz is not. Also, based on sea turtle hearing as reviewed in Appendix I, only airguns 

and boomers are likely to be within their hearing range. 

The safety zone radii based on Southall et al. (2007) criteria were also estimated. The safety radii for 

all sources based on the peak pressure criteria are presented in Table D-24. The safety radii based on the 

sound exposure level criteria are presented in Table D-25 for the airgun array sources and in Table D-26

for the electromechanical sources. Only the cetaceans group was considered, as the abundance of 

pinnipeds inside the AOI is virtually nil. 

The peak pressure decrease with distance was assessed based on the spherical spreading loss 

(Section 2.2.1). The furthest calculated range for injury using the Southall criterion was just 7.7 m from 

the loudest source (airgun array 5,400 in3

). This range is much less than the shallowest water depth out of 

all scenarios. This fact implies that the approach with spherical spreading loss application to be valid. 

Also it indicates that the safety range calculation does not depend on the water depth and the same value 

is good for all scenarios. 

The safety zone radii regarding sound exposure levels were calculated using the transmission loss 

modeling results and corresponding source level for each modeled source expressed in SEL units. Prior 

to the calculation of the safety zone radii, appropriate M-weighting filter was applied to the sound field to 

reflect different audiograms of different marine mammals groups. 

The effect of M-weighting filters application is different for different sources as their frequency 

spectrum varies. The airgun array sources would see virtually no change in the safety zone radii for the 

low-frequency M-weighting filter application, as their dominant frequencies are at the lower end of the 

spectrum. Application of mid- and high-frequency M-weighting filters would reduce the effective source 

level of the airgun array sources, as the filter suppresses the low frequency content of the spectrum; 

hence, the reduction of the safety zone radii. The reverse situation is observed for electromechanical 

sources, whose spectrum is dominated by higher frequencies. The largest reduction in the effective 

source levels and safety zone radii would be achieved by application of the low-frequency M-weighting 

filter, and the mid- and high-frequency M-weighting filter would have smaller effect. 
Acoustic Modeling Report D-53 

Table D-24 

 

Safety Zone Radii (in Meters) Based on Southall et al. (2007) Injury Criterion for the Maximum Peak Pressure 

(Values are applicable to all scenarios.) 

Safety Zone Radii (m) Source Peak Level of Source 

(dB re 1 μPa at 1 m) 230 dB re 1 μPa (peak) 

Airgun array 5,400 in3 247.7 7.7 

Airgun array 90 in3 232.0 1.3 

Boomer 215.0 01

Side-scan sonar 229.0 01

Subbottom profiler 228.2 01

Multibeam depth sounder 213.0 01

1

 Source level is less than the criterion. 

Table D-25 

 

Safety Zone Radii (in Meters) for the Airgun Array Sources Based on Southall et al. (2007) Injury Criterion for the 

Sound Exposure Level (198 dB re 1 μPa2

 s) 

(Calculations were performed on the modeled sound field after application of the relevant M-weighting filter.) 

Source Airgun Array 5,400 in3 Airgun Array 90 in3

Frequency Low Med High Low Med High 

Scenario 198 dB 198 dB 198 dB 198 dB 198 dB 198 dB 

1 18 <5 <5 <5 — — 

2 18 <5 <5 <5 — — 

3 18 <5 <5 <5 — — 

4 18 <5 <5 <5 — — 

5 18 <5 <5 <5 — — 

6 18 <5 <5 <5 — — 

7 18 <5 <5 <5 — — 

8 18 <5 <5 <5 — — 

9 18 <5 <5 <5 — — 

10 18 <5 <5 <5 — — 

11 18 <5 <5 <5 — — 

12 18 <5 <5 <5 — — 

13 18 <5 <5 <5 — — 

14 18 <5 <5 <5 — — 

15 18 <5 <5 <5 — — 

16 18 <5 <5 <5 — — 

17 18 <5 <5 <5 — — 

18 18 <5 <5 <5 — — 

19 18 <5 <5 <5 — — 

20 18 <5 <5 <5 — — 

21 18 <5 <5 <5 — — 
D-54 Atlantic G&G Programmatic EIS 

Table D-26 

 

Safety Zone Radii (in meters) Based on Southall et al. (2007) Injury Criterion Based 

on the Sound Exposure Level (198 dB re 1 μPa2

·s) 

(Values are applicable to all scenarios. The effective source level (SLeff) was calculated based 

on the nominal source level and relevant M-reighting filter.) 

Cetaceans: Low-Frequency Mid-Frequency High-Frequency 

Source SLeff (dB re 1 μPa2

·s)

198 dB 

Radius (m)

SLeff

(dB re 1 μPa2·s)

198 dB 

Radius (m)

SLeff

(dB re 1 μPa2·s)

198 dB 

Radius (m)

Boomer 174.4 01 174.2 01 174.1 01

Side-scan sonar 179.3 01 203.3 2 203.9 2 

Subbottom profiler 212.0 5 213.1 6 213.1 6 

Multibeam depth sounder 131.9 01 163.3 01 164.6 01

1

 Effective source level is less than the criterion. 

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D-58 Atlantic G&G Programmatic EIS 

ATTACHMENT A: Sound Maps 

Predicted sound field maps are shown below for each of the planned model sites. Locations of the 

sites are shown in Figure D-33 of Section 4.2.1. The maps are grouped by scenario (see Table D-19), 

i.e. various sources at the same geographic location (site), bottom type, and same sound velocity profile. 

Approximate SPL (rms), in dB re 1 μPa, is shown in all cases. The modeling results do not account for 

the specific properties of the mammalian hearing such as hearing integration time. Actual acoustic pulse 

duration was used to estimate the presented sound fields. 

Figure Attachment A-1. Predicted SPL (rms) for Modeling Scenario 1 (Water Depth Is 5,390 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 

Figure Attachment A-2. Predicted SPL (rms) for Modeling Scenario 2 (Water Depth Is 2,560 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 
Acoustic Modeling Report D-59 

Figure Attachment A-3. Predicted SPL (rms) for Modeling Scenario 3 (Water Depth Is 880 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 

Figure Attachment A-4. Predicted SPL (rms) for Modeling Scenario 4 (Water Depth Is 249 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 
D-60 Atlantic G&G Programmatic EIS 

Figure Attachment A-5. Predicted SPL (rms) for Modeling Scenario 5 (Water Depth Is 288 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 

Figure Attachment A-6. Predicted SPL (rms) for Modeling Scenario 6 (Water Depth Is 5,390 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 
Acoustic Modeling Report D-61 

Figure Attachment A-7. Predicted SPL (rms) for Modeling Scenario 7 (Water Depth Is 3,200 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 

Figure Attachment A-8. Predicted SPL (rms) for Modeling Scenario 8 (Water Depth Is 880 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 
D-62 Atlantic G&G Programmatic EIS 

Figure Attachment A-9. Predicted SPL (rms) for Modeling Scenario 9 (Water Depth Is 251 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 

Figure Attachment A-10. Predicted SPL (rms) for Modeling Scenario 10 (Water Depth Is 249 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 
Acoustic Modeling Report D-63 

Figure Attachment A-11. Predicted SPL (rms) for Modeling Scenario 11 (Water Depth Is 5,390 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 

Figure Attachment A-12. Predicted SPL (rms) for Modeling Scenario 12 (Water Depth Is 3,200 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 
D-64 Atlantic G&G Programmatic EIS 

Figure Attachment A-13. Predicted SPL (rms) for Modeling Scenario 13 (Water Depth Is 880 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 

Figure Attachment A-14. Predicted SPL (rms) for Modeling Scenario 14 (Water Depth Is 275 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 
Acoustic Modeling Report D-65 

Figure Attachment A-15. Predicted SPL (rms) for Modeling Scenario 15 (Water Depth Is 4,300 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 

Figure Attachment A-16. Predicted SPL (rms) for Modeling Scenario 16 (Water Depth Is 3,010 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 
D-66 Atlantic G&G Programmatic EIS 

Figure Attachment A-17. Predicted SPL (rms) for Modeling Scenario 17 (Water Depth Is 4,890 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 

Figure Attachment A-18. Predicted SPL (rms) for Modeling Scenario 18 (Water Depth Is 3,580 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 
Acoustic Modeling Report D-67 

Figure Attachment A-19. Predicted SPL (rms) for Modeling Scenario 19 (Water Depth Is 880 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 

Figure Attachment A-20. Predicted SPL (rms) for Modeling Scenario 20 (Water Depth Is 100 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 
D-68 Atlantic G&G Programmatic EIS 

Figure Attachment A-21. Predicted SPL (rms) for Modeling Scenario 21 (Water Depth Is 51 m at the Source). 

The Sources Are (a) 5,400 in3

 and (b) 90 in3 Airgun Arrays. 

Figure Attachment A-22. Predicted SPL (rms) for Modeling Scenario 22 (Water Depth Is 30 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, and (c) Side-Scan Sonar. 
Acoustic Modeling Report D-69 

Figure Attachment A-23. Predicted SPL (rms) for Modeling Scenario 23 (Water Depth Is 100 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, (c) Side-Scan Sonar, and 

(d) Multibeam Depth Sounder. 
D-70 Atlantic G&G Programmatic EIS 

Figure Attachment A-24. Predicted SPL (rms) for Modeling Scenario 24 (Water Depth Is 30 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, and (c) Side-Scan Sonar. 
Acoustic Modeling Report D-71 

Figure Attachment A-25. Predicted SPL (rms) for Modeling Scenario 25 (Water Depth Is 100 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, (c) Side-Scan Sonar, and 

(d) Multibeam Depth Sounder. 
D-72 Atlantic G&G Programmatic EIS 

Figure Attachment A-26. Predicted SPL (rms) for Modeling Scenario 26 (Water Depth Is 30 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, and (c) Side-Scan Sonar. 
Acoustic Modeling Report D-73 

Figure Attachment A-27. Predicted SPL (rms) for Modeling Scenario 27 (Water Depth Is 100 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, (c) Side-Scan Sonar, and 

(d) Multibeam Depth Sounder. 
D-74 Atlantic G&G Programmatic EIS 

Figure Attachment A-28. Predicted SPL (rms) for Modeling Scenario 28 (Water Depth Is 30 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, and (c) Side-Scan Sonar. 
Acoustic Modeling Report D-75 

Figure Attachment A-29. Predicted SPL (rms) for Modeling Scenario 29 (Water Depth Is 100 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, (c) Side-Scan Sonar, and 

(d) Multibeam Depth Sounder. 
D-76 Atlantic G&G Programmatic EIS 

Figure Attachment A-30. Predicted SPL (rms) for Modeling Scenario 30 (Water Depth Is 30 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, and (c) Side-Scan Sonar. 
Acoustic Modeling Report D-77 

Figure Attachment A-31. Predicted SPL (rms) for Modeling Scenario 31 (Water Depth Is 100 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, (c) Side-Scan Sonar, and 

(d) Multibeam Depth Sounder. 
D-78 Atlantic G&G Programmatic EIS 

Figure Attachment A-32. Predicted SPL (rms) for Modeling Scenario 32 (Water Depth Is 30 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, and (c) Side-Scan Sonar. 
Acoustic Modeling Report D-79 

Figure Attachment A-33. Predicted SPL (rms) for Modeling Scenario 33 (Water Depth Is 100 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, (c) Side-Scan Sonar, and 

(d) Multibeam Depth Sounder. 
D-80 Atlantic G&G Programmatic EIS 

Figure Attachment A-34. Predicted SPL (rms) for Modeling Scenario 34 (Water Depth Is 30 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, and (c) Side-Scan Sonar. 
Acoustic Modeling Report D-81 

Figure Attachment A-35. Predicted SPL (rms) for Modeling Scenario 35 (Water Depth Is 100 m at the Source). 

The Sources Are (a) Subbottom Profiler, (b) Boomer, (c) Side-Scan Sonar, and 

(d) Multibeam Depth Sounder. 
D-82 Atlantic G&G Programmatic EIS 

ATTACHMENT B: Predicted Ranges to Specified Threshold Levels 

Table Attachment B-1 

 

Predicted Ranges (in Meters) to Specified Threshold Levels for 5,400 in3

 Airgun Array Source 

rms dB 210 200 190 180 170 160 150 

Scenario Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95%

1 29 29 90 87 278 270 835 810 2,297 2,213 5,379 4,969 8,730 8,107 

2 29 29 92 89 284 273 876 827 2,557 2,358 5,720 5,184 19,735 16,479 

3 30 30 91 89 292 280 1,557 1,093 3,753 3,445 9,329 8,104 >20,000 19,489 

4 16 16 46 46 151 145 822 748 3,406 2,793 12,737 8,725 >20,000 19,338 

5 16 16 47 45 166 153 816 742 3,635 2,709 13,337 8,896 >20,000 19,265 

6 29 29 90 87 278 270 837 811 2,298 2,215 5,379 4,989 8,740 8,146 

7 29 29 90 87 285 276 855 829 2,422 2,300 5,322 5,026 19,950 18,775 

8 30 30 91 89 292 280 1,556 1,091 3,748 3,452 9,654 8,056 >20,000 19,489 

9 16 16 46 46 154 148 801 737 3,305 2,787 11,056 8,593 >20,000 19,327 

10 16 16 45 43 152 146 799 752 3,361 2,704 11,695 8,615 >20,000 18,989 

11 29 29 89 86 277 269 837 811 2,296 2,212 5,379 4,973 8,320 7,883 

12 29 29 89 87 283 275 853 827 2,420 2,291 5,320 5,013 >20,000 19,758 

13 30 29 90 88 292 280 1,552 1,082 3,737 3,151 9,316 8,095 >20,000 19,489 

14 16 16 45 43 157 150 880 761 3,253 2,648 15,305 9,122 >20,000 19,387 

15 30 29 91 89 280 273 841 816 2,365 2,262 5,490 5,121 8,846 8,394 

16 30 29 90 87 285 277 871 846 2,456 2,339 5,360 5,098 19,852 16,233 

17 29 29 90 88 279 271 838 812 2,281 2,212 5,184 4,959 8,590 8,235 

18 30 29 90 87 278 270 845 819 2,362 2,267 5,450 5,069 8,912 8,384 

19 30 30 91 89 292 280 1,559 1,094 3,754 3,497 9,304 8,083 >20,000 19,489 

20 16 16 49 47 292 275 1,134 992 4,127 3,282 12,022 8,531 >20,000 19,151 

21 21 21 92 87 460 434 2,109 1,677 5,257 4,441 11,380 8,384 >20,000 18,421 
Acoustic Modeling Report D-83 

Table Attachment B-2 

 

Predicted Ranges (in Meters) to Specified Threshold Levels for 90 in3

 Airgun Array Source 

rms dB 200 190 180 170 160 150 

Scenario Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95%

1 16 16 46 46 148 144 450 437 1,295 1,256 3,412 3,205 

2 16 16 46 46 148 143 458 441 1,363 1,291 3,719 3,355 

3 16 16 47 47 148 145 486 460 2,210 2,038 5,537 4,786 

4 7 7 22 22 76 75 325 293 1,452 1,342 4,990 4,154 

5 7 7 22 22 76 74 395 328 1,568 1,286 5,324 3,927 

6 16 16 46 46 148 144 450 437 1,295 1,256 3,412 3,202 

7 16 16 46 46 146 142 453 439 1,322 1,281 3,565 3,302 

8 16 16 47 47 148 145 483 459 2,212 2,039 5,516 4,810 

9 7 7 22 22 76 74 332 306 1,464 1,331 4,910 4,374 

10 7 7 25 25 76 75 310 291 1,512 1,108 5,189 4,126 

11 16 16 46 46 146 143 448 435 1,295 1,255 3,412 3,203 

12 16 16 46 46 146 141 450 437 1,321 1,280 3,425 3,307 

13 16 16 47 46 147 143 482 458 2,211 2,036 5,197 4,623 

14 7 7 25 25 76 74 336 308 1,371 1,100 5,456 3,947 

15 16 16 47 46 146 143 450 436 1,315 1,258 3,403 3,284 

16 16 16 46 46 149 145 455 442 1,325 1,285 3,529 3,404 

17 16 16 46 46 149 145 455 442 1,294 1,255 3,351 3,194 

18 16 16 46 46 148 145 456 443 1,329 1,289 3,510 3,294 

19 16 16 47 47 149 145 483 459 2,212 2,040 5,518 4,859 

20 7 7 25 25 90 86 371 341 2,051 1,681 5,181 4,356 

21 11 11 35 35 186 177 852 755 3,056 2,493 6,464 5,888 
D-84 Atlantic G&G Programmatic EIS 

Table Attachment B-3 

 

Predicted Ranges (in Meters) to Specified Threshold Levels for Boomer Source. 

No Adjustment for Pulse Duration Has Been Applied 

rms dB 200 190 180 170 160 150 

Scenario Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95%

22 <5 <5 7 7 43 43 386 336 1,737 1,490 8,243 6,088 

23 <5 <5 7 7 39 38 140 135 1,060 818 6,655 4,757 

24 <5 <5 7 7 43 42 364 299 1,956 1,444 6,280 5,056 

25 <5 <5 7 7 38 36 142 132 1,566 1,342 7,820 4,792 

26 <5 <5 7 7 43 41 386 317 1,712 1,428 7,293 5,752 

27 <5 <5 7 7 40 40 141 135 1,054 807 6,003 4,519 

28 <5 <5 7 7 41 40 259 252 1,860 1,468 8,202 6,252 

29 <5 <5 7 7 39 38 144 137 1,129 799 6,484 4,805 

30 <5 <5 7 7 43 41 315 310 1,730 1,435 6,776 5,563 

31 <5 <5 10 10 40 39 146 137 1,155 840 6,480 4,550 

32 <5 <5 7 7 45 43 377 318 2,138 1,552 7,802 6,287 

33 <5 <5 7 7 39 38 148 142 1,655 898 7,089 5,046 

34 <5 <5 7 7 43 43 376 313 1,844 1,467 7,755 6,011 

35 <5 <5 7 7 40 38 143 137 1,035 669 6,085 4,339 

Table Attachment B-4 

 

Predicted Ranges (in Meters) to Specified Threshold Levels for Side-Scan Sonar Source. 

No Adjustment for Pulse Duration Has Been Applied 

rms dB 210 200 190 180 170 160 150 

Scenario Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95%

22 <5 <5 18 16 70 66 192 180 376 334 604 534 856 732 

23 <5 <5 12 8 47 36 128 116 280 250 512 440 760 650 

24 <5 <5 18 16 70 66 186 176 376 336 602 532 864 752 

25 <5 <5 12 8 47 36 138 116 290 256 532 455 812 715 

26 <5 <5 18 16 70 66 190 176 374 330 600 530 852 728 

27 <5 <5 12 8 47 36 128 116 280 246 500 438 770 651 

28 <5 <5 14 12 50 47 177 156 379 345 655 528 919 791 

29 <5 <5 14 12 50 47 133 125 348 330 650 499 867 774 

30 <5 <5 13 9 49 42 171 154 356 319 576 510 850 737 

31 <5 <5 13 9 49 39 129 115 286 247 537 462 816 702 

32 <5 <5 13 9 49 42 178 156 366 323 600 539 903 745 

33 <5 <5 13 9 49 39 132 119 293 256 567 492 806 697 

34 <5 <5 13 9 53 40 175 159 362 324 592 526 836 719 

35 <5 <5 13 9 47 30 134 121 281 249 538 458 768 655 
Acoustic Modeling Report D-85 

Table Attachment B-5 

 

Predicted Ranges (in Meters) to Specified Threshold Levels for Chirp Subbottom Profiler. 

No Adjustment for Pulse Duration Has Been Applied 

rms dB 200 190 180 170 160 150 

Scenario Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95%

22 <5 <5 12 12 32 28 136 110 808 682 2,863 2,325 

23 <5 <5 13 13 38 35 106 90 380 303 2,456 1,781 

24 <5 <5 12 12 32 28 138 112 874 772 2,908 2,379 

25 <5 <5 13 13 37 35 108 90 376 317 2,855 2,357 

26 <5 <5 12 12 32 28 128 107 764 664 2,839 2,275 

27 <5 <5 13 13 37 35 106 90 359 297 2,480 1,741 

28 <5 <5 13 12 33 29 122 102 971 876 3,222 2,857 

29 <5 <5 13 13 42 37 110 91 854 677 3,189 2,704 

30 <5 <5 13 12 33 29 122 103 831 644 2,680 2,199 

31 <5 <5 13 13 42 39 112 91 557 313 2,324 1,969 

32 <5 <5 13 12 33 29 125 104 962 811 3,494 2,519 

33 <5 <5 13 13 42 39 112 92 684 363 2,889 2,446 

34 <5 <5 13 12 32 29 123 104 724 634 2,869 2,590 

35 <5 <5 13 13 42 38 108 90 401 300 2,766 2,086 

Table Attachment B-6 

 

Predicted Ranges (in Meters) to Specified Threshold Levels for Multibeam Depth Sounder. 

No Adjustment for Pulse Duration Has Been Applied 

rms, dB 210 200 190 180 170 160 150 

Scenario Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95% Rmax R95%

23 0 0 <5 <5 10 10 27 25 61 57 147 142 320 275 

25 0 0 <5 <5 10 10 27 25 61 57 147 142 320 275 

27 0 0 <5 <5 10 10 27 25 61 57 147 142 315 269 

29 0 0 <5 <5 10 10 27 25 55 51 156 149 359 337 

31 0 0 <5 <5 10 10 27 25 61 57 147 140 294 262 

33 0 0 <5 <5 10 10 27 25 61 57 147 140 305 273 

35 0 0 <5 <5 10 10 27 25 59 55 149 144 293 266 

APPENDIX E 

ACOUSTIC MODELING AND MARINE MAMMAL INCIDENTAL 

TAKE METHODOLOGY, ANALYSIS, AND RESULTS

Acoustic Modeling and Marine Mammal Incidental Take Methodology E-iii 

TABLE OF CONTENTS 

Page 

1. INTRODUCTION AND OVERVIEW............................................................................................. E-1

2. ACOUSTIC MODELING APPROACH .......................................................................................... E-2

2.1. Propagation Modeling.............................................................................................................. E-3

2.1.1. Overall Modeling Assumptions ................................................................................... E-3

2.1.2. Acoustic Propagation Model Selection ........................................................................ E-4

2.2. Overall Modeling Approach .................................................................................................... E-4

3. ACOUSTIC THRESHOLDS............................................................................................................ E-5

3.1. Historical and Proposed Current Criteria................................................................................. E-5

3.1.1. Injury Criteria............................................................................................................... E-5

3.1.2. Behavioral Disturbance Criteria................................................................................... E-6

4. ACOUSTIC SOURCE MODELING................................................................................................ E-7

5. AREA ACOUSTIC PROPAGATION CHARACTERIZATION .................................................... E-7

5.1. General Characterization of All Operational Areas................................................................. E-7

5.1.1. Propagation .................................................................................................................. E-8

5.1.1.1. Winter ......................................................................................................... E-11

5.1.1.2. Spring ......................................................................................................... E-12

5.1.1.3. Summer....................................................................................................... E-13

5.1.1.4. Fall.............................................................................................................. E-14

5.1.2. Bottom Loss ............................................................................................................... E-16

5.1.3. General Characterization Summary ........................................................................... E-18

5.2. Shallow Water Modeling for Marine Minerals and Renewable Energy................................ E-26

6. MARINE MAMMAL ABUNDANCES AND DENSITIES .......................................................... E-27

7. IMPACT MODELING APPROACHES ........................................................................................ E-31

7.1. AIM Modeling and Methodology.......................................................................................... E-31

7.2. AIM Modeling of the Source Movement............................................................................... E-32

7.3. AIM Modeling of the Animal Movement.............................................................................. E-33

7.3.1. Movement .................................................................................................................. E-33

7.3.2. Heading Variance....................................................................................................... E-34

7.3.3. Aversions.................................................................................................................... E-34

7.3.4. Species Behavior Parameters ..................................................................................... E-34

7.3.4.1. Minke Whale .............................................................................................. E-35

7.3.4.2. Sei/Bryde’s Whale...................................................................................... E-36

7.3.4.3. Blue Whale ................................................................................................. E-37

7.3.4.4. Fin Whale ................................................................................................... E-38

7.3.4.5. North Atlantic Right Whale........................................................................ E-39

7.3.4.6. Humpback Whale (Feeding)....................................................................... E-40

7.3.4.7. Humpback Whale (Winter Grounds: Singer) ............................................. E-41

7.3.4.8. Humpback Whale (Migrating).................................................................... E-42

7.3.4.9. Common Dolphin ....................................................................................... E-43

7.3.4.10. Blackfish: False Killer Whale, Pygmy Killer Whale, Melon-headed 

Whale.......................................................................................................... E-43

7.3.4.11. Shortfin and Longfin Pilot Whales............................................................. E-44

7.3.4.12. Risso’s Dolphin .......................................................................................... E-45

7.3.4.13. Large Beaked Whales................................................................................. E-46

7.3.4.14. Dwarf and Pygmy Sperm Whales (Kogia spp.).......................................... E-47
E-iv Atlantic G&G Programmatic EIS

7.3.4.15. Lagenorhynchus Species ............................................................................ E-48

7.3.4.16. Fraser’s Dolphin ......................................................................................... E-49

7.3.4.17. Small Beaked Whales (Mesoplodon, Ziphius, Tasmacetus) ...................... E-49

7.3.4.18. Killer Whale ............................................................................................... E-51

7.3.4.19. Harbor Porpoise.......................................................................................... E-52

7.3.4.20. Sperm Whale .............................................................................................. E-52

7.3.4.21. Stenella: Spinner, Spotted and Striped Dolphins....................................... E-55

7.3.4.22. Bottlenose Dolphin..................................................................................... E-56

7.4. Estimations of Source Level of Effort ................................................................................... E-57

7.4.1. Annual Survey Levels of Effort (LOE)...................................................................... E-58

7.4.2. Spatial Distribution of the 2D Survey Effort.............................................................. E-58

7.4.3. Temporal Correction to Level of Effort (LOE) Tables to Account for Area 

Closures...................................................................................................................... E-60

7.5. AIM Results and Adjustments ............................................................................................... E-64

7.5.1. Modeling Results........................................................................................................ E-64

7.5.2. Discussion of the Uncertainty of the Modeling Effort ............................................... E-69

8. REFERENCES CITED................................................................................................................... E-70

ATTACHMENT: Summary Tables of Total Annual Take Estimates................................................... E-80
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-v 

LIST OF FIGURES 

Page 

Figure E-1 Area of Interest (black line) Plotted over Bathymetry from the Digital Bathymetric 

Data Base Variable Resolution Database (depth in feet) .................................................... E-8

Figure E-2 Provinced Generalized Digital Environmental Model (GDEM) Areas within the 

Area of Interest (black line) ................................................................................................ E-8

Figure E-3 Example of Surface Layer Trapped Acoustic Energy....................................................... E-10

Figure E-4 Example of the Convergence Zone Propagation............................................................... E-11

Figure E-5 Winter Propagation Characteristics of the Area of Interest (black line)........................... E-12

Figure E-6 Spring Propagation Characteristics of the Area of Interest (black line)............................ E-13

Figure E-7 Winter Propagation Characteristics of the Area of Interest (black line)........................... E-14

Figure E-8 Fall Propagation Characteristics of the Area of Interest (black line)................................ E-15

Figure E-9 Grain Size Index for the Area of Interest .......................................................................... E-18

Figure E-10 Rayleigh Bottom Loss Estimates for Grain Size Index 7, 1, and -1 ................................. E-18

Figure E-11 Final Modeling Regions for the Winter ............................................................................ E-22

Figure E-12 Final Modeling Regions for the Spring............................................................................. E-23

Figure E-13 Final Modeling Regions for the Summer.......................................................................... E-24

Figure E-14 Final Modeling Regions for the Fall ................................................................................. E-25

Figure E-15 Density Plot for Atlantic Spotted Dolphin for Fall based on the Navy Operating 

Area Density Estimate Database (U.S. Dept. of the Navy, 2007b)................................... E-29

Figure E-16 Typical Dive Pattern ......................................................................................................... E-33

Figure E-17 Parameters Used to Specify the Typical Dive Pattern Shown in Figure E-16.................. E-34

Figure E-18 Example Showing the Aversions to Limit an Animat to Waters between 2,000 and 

5,000 m (6,562 and 16,404 ft)........................................................................................... E-34

Figure E-19 Level of Effort Density Plot for Future 2D Seismic Airgun Surveys Based on 

Overlay of Seismic Survey Applications Submitted to BOEM ........................................ E-59

Acoustic Modeling and Marine Mammal Incidental Take Methodology E-vii 

LIST OF TABLES 

Page 

Table E-1 Historical Injury and Behavioral Disturbance Criteria for Cetaceans and Pinnipeds 

for Airgun Signals, as Recognized and Used by the National Marine Fisheries 

Service................................................................................................................................. E-5

Table E-2 Injury and Behavioral Disturbance Exposure Criteria for Cetaceans and Pinnipeds, 

as proposed by Southall et al. (2007).................................................................................. E-6

Table E-3 Month Used to Represent each Season in Sound Speed Database Extraction.................... E-9

Table E-4 Grain Size Index for Sediment Type................................................................................. E-16

Table E-5 Summary of Propagation and Bottom Loss Characterization in the Area of Interest....... E-20

Table E-6 Summary Table of the Sound Velocity Profiles Used in the Characterization of the 

Area................................................................................................................................... E-21

Table E-7 Summary of Details of the Sites Identified in the Shallow Water Characterization......... E-27

Table E-8 Marine Mammal Densities for the 21 Modeling Regions (U.S. Dept. of the Navy, 

2007b) ............................................................................................................................... E-30

Table E-9 Seismic Airgun Source Vessel Parameters for AIM Simulations..................................... E-33

Table E-10 Marine Mineral and Renewable Resource Source Vessel Parameters for AIM 

Simulations ....................................................................................................................... E-33

Table E-11 Projected Levels of Seismic Airgun Surveys for Oil and Gas Exploration in the 

Mid- and South Atlantic Planning Areas, 2012-2020....................................................... E-58

Table E-12 Adjusted Level of Effort in Blocks for 2D Seismic Airgun Surveys................................ E-61

Table E-13 Adjusted Level of Effort in Blocks for 3D Seismic Airgun Surveys................................ E-61

Table E-14 Adjusted Level of Effort in Blocks for WAZ Seismic Airgun Surveys............................ E-62

Table E-15 Adjusted Level of Effort in Blocks for VSP Seismic Airgun Surveys ............................. E-62

Table E-16 Adjusted Level of Effort in Blocks for 90 Cubic Inch Airgun HRG Surveys for Oil 

and Gas Sites..................................................................................................................... E-63

Table E-17 Adjusted Level of Effort in Blocks for Non-Airgun HRG Surveys for Marine 

Minerals Sites.................................................................................................................... E-63

Table E-18 Adjusted Level of Effort in Blocks for Non-Airgun HRG Surveys for Renewable 

Energy Sites ...................................................................................................................... E-64

Table E-19 Potential Level A Takes (number of individuals) for One Block of 2D Seismic 

Airgun Survey Effort, Based on the Southall et al (2007) Injury Criteria ........................ E-65

Table E-20 Potential Level A Takes (number of individuals) for One Block of 2D Seismic 

Airgun Survey Effort, Based on the Historic NMFS Criterion (180 dB).......................... E-66

Table E-21 Potential Level B Takes (number of individuals) for One Block of 2D Seismic 

Airgun Survey Effort, Based on the Historic NMFS Criterion (160 dB)......................... E-67

Acoustic Modeling and Marine Mammal Incidental Take Methodology E-ix 

LIST OF ACRONYMS AND ABBREVIATIONS 

μPa micropascals 

2D two-dimensional 

3D three-dimensional 

4D four-dimensional 

AIM Acoustic Integration Model©

ANSI American National Standards 

Institute 

AOI Area of Interest 

BOEM Bureau of Ocean Energy 

Management 

CIE Center for Independent Experts 

CZ convergence zone 

dB decibel 

DTAG digital acoustic recording tag 

EIS environmental impact statement 

FEIS Final Environmental Impact 

Statement 

FSEIS Final Supplemental Environmental 

Impact Statement 

ft feet 

G&G geological and geophysical 

GIS geographic information system 

GDEM Generalized Digital Environmental 

Model 

GDEM_V Generalized Digital Environmental 

Model Variable Resolution 

hr hour 

HRG high-resolution geophysical 

Hz hertz 

ITA incidental take authorization 

JASCO JASCO Applied Sciences 

kHz kilohertz 

km kilometer 

LFA low-frequency active 

LOE level of effort 

m meter 

MMPA Marine Mammal Protection Act 

MONM Marine Operations Noise Model 

NGDC National Geophysical Data Center 

NMFS National Marine Fisheries Service 

nmi nautical mile 

NODE Navy Operating Area Density 

Estimates 

NRC National Research Council 

OCS Outer Continental Shelf 

OPAREA operating area 

Pa pascal 

PTS permanent threshold shift 

RMS root-mean-square 

s second 

SAG surface active group 

SD standard deviation 

SE standard error 

SEFSC Southeast Fisheries Science Center 

SEL sound exposure level 

SL source level 

SPL sound pressure level 

SURTASS Surveillance Towed Array Sensor 

System 

SVP sound velocity profile 

TDR time-depth recorder 

TL transmission loss 

TTS temporary threshold shift 

VSP vertical seismic profile 

WAZ wide azimuth 

Acoustic Modeling and Marine Mammal Incidental Take Methodology E-1 

1. INTRODUCTION AND OVERVIEW 

The Bureau of Ocean Energy Management (BOEM) has prepared this Programmatic Environmental 

Impact Statement (EIS) to evaluate the potential environmental effects of geological and geophysical 

(G&G) activities on the Mid- and South Atlantic Outer Continental Shelf (OCS) and adjacent state 

waters. The purpose of this appendix is to explain the methodology that was used to calculate incidental 

takes of marine mammals for the Programmatic EIS. This appendix documents the overall approach and 

identifies the specific models, acoustic sources, and modeling techniques that were used, as well as the 

operational, environmental, and biological data that were needed to support the modeling. Some of the 

details of this analysis are specific to the work performed by JASCO as part of their acoustic source and 

acoustic propagation loss modeling; in those instances, this appendix refers to Appendix D, which covers 

those details. 

The term “incidental take” derives from Section 101(a)(5) (A-D) of the Marine Mammal Protection 

Act of 1972 (MMPA), as amended (16 U.S.C. 1371(a)(5)), which provides a mechanism for allowing, 

upon request, the incidental, but not intentional, taking of small numbers of marine mammals by 

U.S. citizens who engage in a specified activity (other than commercial fishing) within a specified 

geographic region. Under the 1994 amendments to the MMPA, harassment is statutorily defined as, “any 

act of pursuit, torment, or annoyance that has the potential to injure a marine mammal or marine mammal 

stock in the wild” (Level A harassment); “or has the potential to disturb a marine mammal or marine 

mammal stock in the wild by causing disruption of behavioral patterns including, but not limited to, 

migration, breathing, nursing, breeding, feeding, or sheltering but which does not have the potential to 

injure a marine mammal or marine mammal stock in the wild” (Level B harassment). 

Accurate predictive modeling of potential acoustic impacts requires knowledge of (1) the specific 

source(s) that would be used at each site of survey operations; (2) the exact environmental acoustic 

conditions present at each site; (3) the timing and type of each survey; and (4) the marine animals present 

at each site. Because these facts could not be known ahead of time (without extensive surveys 

immediately prior to or during the survey) and particularly not for the period of this document 

(i.e., through the year 2020), the following analytical estimation is necessary. The reasonable approach 

described in this report, in general, examines the potential range of each variable and identifies typical 

values expected to be used during the proposed action. 

There are many instances where the numerous permutations needed to capture the effects of the range 

of values for a variable may be able to be reduced because of minimal effects on the results, or because 

the low occurrence of some of the values in the range allows an obvious selection for modeling. For 

example, nearly all of the deepwater sites have very fine silts, clayey silt, and clay as the predominant 

bottom types, and the use of clay characteristics in the acoustic propagation modeling for all of these deep 

sites is adequate, because the bottom properties of the other sediments would be similar. Similarly, in the 

case of the airgun source used for modeling, there are numerous possible source arrays that could be used 

based on the company performing the survey, the location, the ships available, etc. In this case, a nominal 

source identified by the BOEM as a typical source for these surveys was used in the modeling. Although 

it is not necessarily the strongest source identified, it better represents a typical source array and its 

potential impacts. It is estimated that the percentage of time that strong and weak sources are used over 

the duration of the proposed action would only slightly change the overall estimated impacts and, over 

time, tend to average out to an impact similar to that predicted for the modeled array. As can be seen in 

Appendix D, the 5,400 cubic inch airgun is conservatively used for all survey types (e.g., a 

two-dimensional [2D] survey might be expected to typically use a smaller and less powerful source), with 

the source level only being corrected for the water depth and M-weighting. 

The basic acoustic terminology used in this report is presented in numerous published sources 

(e.g., American National Standards Institute [ANSI], 1984, 1986, 2004; Richardson et al., 1995; National 

Research Council [NRC], 2003; Southall et al., 2007). The main definitions used in this assessment are 

provided below, from Southall et al. (2007): 

 Pulses: Pulses are brief, broadband, atonal, transient sounds; e.g., explosions, gun 

shots, airgun pulses, and pile driving strikes. Pulses are characterized by a rapid rise 

from ambient pressure to maximal pressure, and (at least near the source) by short 

duration. 
E-2 Atlantic G&G Programmatic EIS

 Nonpulse (intermittent or continuous) Sounds: Nonpulse sounds can be tonal, 

broadband, or both. Nonpulse sounds can be of short duration but they lack the rapid 

rise times of true pulses. Nonpulse sounds include those from shipping, aircraft, 

drilling, and active sonar systems. Due to certain propagation effects, it is possible 

that a sound that is pulsed near the source may be perceived by a distant receiver as a 

nonpulse sound. 

 Peak Sound Pressure: This is the maximum instantaneous sound pressure 

measurable in the water at a specified distance from the source airgun. The units of 

pressure are typically bars (English) or, in metric units, either Pascals (Pa) or 

microPascals (μPa). The metric values are commonly expressed in logarithmic form 

as decibels relative to 1 μPa (dB re 1 μPa). 

 Peak-to-Peak Sound Pressure: This is the algebraic difference between the peak 

positive and peak negative sound pressures. Units are the same as for peak pressure. 

When expressed in dB, peak-to-peak pressure is typically ~6 dB higher than peak 

pressure. 

 Root-Mean-Square (RMS) Sound Pressure: In simple terms, this is an average sound 

pressure over some specified time interval. For airgun pulses, the averaging time is 

commonly taken to be the approximate duration of one pulse, which in turn is 

commonly assumed to be the time interval within which 90 percent of the pulse 

energy arrives. The RMS sound pressure level (in dB) is typically ~10 dB less than 

the peak level, and ~16 dB less than the peak-to-peak level. 

 Sound Pressure Levels (SPLs): The SPLs are given as the dB measures of the 

pressure metrics defined above. The RMS SPL is given as dB re: 1 μPa for 

underwater sound and dB re: 20 μPa for aerial sound. 

 Source Level (SL): The SL is the received level measured or estimated at a nominal 

distance of 1 meter (m) from the source. It is often expressed as dB re: 1 μPa at 1 m 

or in bar-m. For a distributed source, such as an array of airguns, the nominal overall 

SL, as used in predicting received levels at long distances, exceeds the level 

measurable at any one point in the water near the sources. 

 Sound Exposure Level (SEL or energy flux density): This measure represents the 

total energy contained within a pulse, and is in the units dB re 1 μPa2-s. For a single 

airgun pulse, the numerical value of the SEL measurement, in these units, is usually 

5–15 dB lower than the RMS sound pressure in dB re 1 μPa, with the “RMS – SEL” 

difference often tending to decrease with increasing range (Greene, 1997; McCauley 

et al., 1998). 

 Duration: Duration is the length of the sound, usually measured in seconds. For an 

impulsive sound such as an airgun pulse, the duration may be calculated in a number 

of different ways. Greene (1997) described duration of an airgun pulse as the interval 

over which 90 percent of the sound energy arrives at the receiver. 

Over the past decade, the National Marine Fisheries Service (NMFS) guidelines regarding levels of 

impulsive sound that might cause injury or behavioral disturbance have been based on the “RMS sound 

pressure” metric. However, the RMS value depends on the extent to which the sound pulse has been 

“stretched” in duration during propagation, which varies with environmental conditions, so the RMS 

measure is often criticized (e.g., Madsen, 2005). There is now reason to believe that auditory effects 

(especially physiological effects like permanent threshold shift [PTS] and temporary threshold shift 

[TTS]) of transient sounds on marine mammals are better correlated with the amount of received energy 

than with the level of the strongest pulse and therefore SEL is increasingly the unit of choice in 

evaluations (Southall et al., 2007). 

2. ACOUSTIC MODELING APPROACH 

There are two steps to the modeling effort: (1) the determination of the three-dimensional (3D) 

acoustic field emanating from the sound sources and how it propagates through the water; and (2) the 

determination of the net exposure of marine animals that reside in the exposed volume. 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-3 

Historically, the geophysical community and NMFS have used a simplified approach (referred to here 

as the “transect methodology”) to estimate the potential impacts to marine mammals for airgun sources. 

Essentially, this methodology consisted of: (1) determination of the estimated threshold isopleth range 

from the source for harassment under the MMPA for the airgun sources. Nominally these thresholds 

were the 160 dB received level for Level B harassment of any marine mammal and the 180 and 190 dB 

received levels for Level A harassment of cetaceans and pinnipeds, respectively; (2) assumption that a 

cylinder whose radius matched the range to these isopleths and encompassed the entire water column was 

ensonified to that threshold; (3) calculating the surface area ensonified by this water column as the source 

moved along its track; and (4) multiplying that resultant ensonified surface area by the density of each 

marine mammal species present to estimate that species’ numbers of MMPA Level A and B potential 

harassment takes. This methodology was not used in the Programmatic EIS. 

For the Programmatic EIS a more sophisticated approach was used. This approach used a more 

detailed modeling of the source and its properties, the acoustic propagation field in 3D, and 3D animal 

placement and movement to better calculate the potential impacts to marine mammals. For this 

methodology, the first step is largely controlled by properties of the source, such as its movement in time 

and space, and the sound field it generates at any point in time. This is a function of the geometric 

organization (array configuration) of its sound generators, and the spatial, spectral, and temporal 

properties of the sound field that they produce. Propagation modeling further analyzes the effects of the 

physical properties of the ocean, the bottom and the surface, on the sound field as it propagates out from 

the source. 

The second step requires knowledge of the diving and movement characteristics of the animals 

residing in the exposed region. Time-based integration models, such as the Acoustic Integration Model© 

(AIM)1, as used in this modeling effort, are necessary to fully evaluate the exposure. The advantage of 

these tools is that they not only provide a more accurate and detailed model of the exposures of a 

population of marine animals in 3D and time, but they also provide: (1) statistical data on each 

individually modeled animal and the population as a whole; (2) rate of exposure (sounds per unit of time) 

over the duration of a survey; and (3) the data necessary to determine effects based on more sophisticated 

thresholds, such as SEL. 

2.1. PROPAGATION MODELING

2.1.1. Overall Modeling Assumptions 

For the more complex modeling effort in this appendix, the following general assumptions were 

made: 

 the far-field broadband signal from the typical airgun array nominally includes 

significant components up to 2,000 hertz (Hz), with the peak amplitude in the 

far-field near-horizontal spectrum typically occurring between 50 and 100 Hz; 

 the modeling needs to address all of the seismic airgun survey types identified in the 

scope of work for this effort – i.e., 2D and 3D surveys, wide azimuth (WAZ) surveys, 

vertical seismic profiles (VSP), and high-resolution geophysical (HRG) surveys; 

 the modeling also needs to address HRG surveys for renewable energy and marine 

minerals sites, which use non-airgun active acoustic sources including side-scan 

sonars, boomers, chirp subbottom profilers, and single or multibeam depth sounders; 

 there would also be non-acoustic surveys (i.e., controlled source electromagnetic 

surveys, magnetotelluric surveys, gravity and gradiometry surveys, magnetic surveys, 

deep stratigraphic and shallow test drilling, bottom sampling, and several remote 

sensing methods), but they are not addressed by this acoustic modeling effort; 

 1

 MAI’s Acoustic Integration Model©, or AIM, is a software package developed to predict the acoustic exposure of marine 

animals from an underwater sound source. The unique and principal component of AIM is a 3D movement engine, which 

programs the geographic and vertical movements of sound sources and simulated marine animals. In 2006, the Center for 

Independent Experts (CIE) conducted a review and assessment of AIM. The CIE panel concluded that AIM is a credible tool 

for developing application models (Independent System for Peer Review, 2006). 
E-4 Atlantic G&G Programmatic EIS

 nominal or representative sources, as identified by the BOEM, were used for source 

modeling and source specification identification; 

 conditions to be modeled include all potential survey areas in the Area of Interest 

(AOI) for the Programmatic EIS, including all water depths from the coastline 

(outside of estuaries) to 350 nautical miles (nmi) (648 kilometers [km]) from shore 

and including all four seasons; 

 animal density estimates would use the best available data, specified by location and 

season for the modeling effort; and 

 animal movement modeling would use the best available input data. 

2.1.2. Acoustic Propagation Model Selection 

The details of the acoustic propagation modeling are provided in Appendix D and will not be 

repeated here. 

2.2. OVERALL MODELING APPROACH

The following step-wise modeling approach is included to illustrate the overall approach to predict 

the acoustic impacts of G&G activities in the Mid- and South Atlantic for the proposed action: 

 The Generalized Digital Environmental Model (GDEM) database was used to extract 

sound velocity profiles (SVPs) for the Mid- and South Atlantic Planning Areas to 

characterize the entire water body into a discreet number of specific SVP regions, or 

propagation regions; 

 The SVPs for winter, spring, summer, and fall were then examined for the entire area 

covered by this Programmatic EIS. After examination of the SVPs, it was 

determined each season had unique characteristics which prevented any combination 

of seasons with similar propagation characteristics. Additionally, the SVPs for each 

season were group into about 17 areas or regions with similar propagation 

characteristics and representative SVPs for each region were selected. Finally, the 

bottom characteristics for each of these 17 regions were examined to determine if any 

region needed to be divided to accommodate the influence of the various bottom 

types on that regions propagation. The result was 21 separate modeling regions that 

taken in total captured the propagation for the entire area covered by this 

Programmatic EIS for all four seasons; 

 Additionally, the seasonal distribution of marine mammals was examined using the 

best available databases to see if there was any additional correlation with 

bathymetry and SVP regions. Using this database, the seasonal distribution for each 

species was examined by overlaying the charts of the 21 acoustic modeling regions; 

the average density of each species was then numerically determined for each region. 

 One final acoustic characterization was then conducted in order to allow the correct 

acoustic modeling for the shallowest water activities. Of the 21 modeling regions, 

7 regions covered the area of the continental shelf, but these areas included water 

depths of up to approximately 200 m (656 feet [ft]). Since all of the marine mineral 

and renewable energy HRG surveys would be conducted in water less than 100 m 

(328 ft) deep, a refined propagation analysis using 50 and 100 m (164 and 328 ft) 

deep sites were identified for each of these 7 shallow water regions. The acoustics 

modeling would use these 14 additional sites to properly capture the acoustic 

propagation for these two categories of non-airgun HRG surveys; 

 JASCO Applied Sciences (JASCO) provided the acoustic propagation modeling and 

results for all sources and the regions that they would potentially operate in as 

described in Appendix D; 

 The AIM was used to estimate the impacts per survey block for each species, based 

on the typical planned geometry for each type of survey in each modeled area where 

the surveys would be conducted, using the appropriate thresholds for that species. 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-5 

3. ACOUSTIC THRESHOLDS 

3.1. HISTORICAL AND PROPOSED CURRENT CRITERIA

Since the mid-1990s, the NMFS has specified that marine mammals exposed to pulsed sounds with 

received levels exceeding 180 or 190 dB re 1 μPa (RMS) for cetaceans and pinnipeds, respectively, were 

considered to exceed Level A (Injury) levels. Similarly, NMFS specifies that cetaceans and pinnipeds 

exposed to levels exceeding 160 dB re 1 μPa (RMS) were considered to exceed Level B (Behavioral 

Harassment) criteria (Table E-1). For all of these criteria, the exposure level was the maximum acoustic 

RMS pressure level received by an animal. 

Table E-1 

 

Historical Injury and Behavioral Disturbance Criteria for Cetaceans and Pinnipeds for Airgun Signals, 

as Recognized and Used by the National Marine Fisheries Service 

Group 

Level A (Injury) 

Pressure 

(dB re 1 μPa RMS) 

Level B (Behavioral Disturbance) 

Pressure 

(dB re 1 μPa RMS) 

Cetaceans 180 160 

Pinnipeds 190 160 

3.1.1. Injury Criteria 

The 180- and 190-dB re 1 μPa (RMS) criteria were determined before there was specific information 

about the received levels of underwater sound that would cause temporary or permanent hearing damage 

in marine mammals. Subsequently, data on received levels that cause the onset of TTS have been 

obtained for certain toothed whales and pinnipeds (Kastak et al., 1999, 2005; Finneran et al., 2002, 2005). 

A group of specialists in marine mammal acoustics, the “noise criteria group,” has recommended new 

criteria, based on current scientific knowledge, to replace the somewhat arbitrary 180 and 190 dB (RMS) 

criteria (Southall et al., 2007). 

Recently acquired data indicate that TTS-onset in marine mammals is more closely correlated with 

the received energy levels than with RMS levels. In odontocetes and the more sensitive pinnipeds 

exposed to nonpulse sound, TTS onset occurs near 195 and 183 dB re 1 μPa2 -s, respectively (Southall et 

al., 2007). In odontocetes exposed to impulse sounds, the TTS threshold can be as low as approximately 

186 dB re 1 μPa2

-s. The corresponding value for pinnipeds is less well defined. There are published data 

on levels of nonpulse sound (Kastak et al., 1999, 2005) but not of impulse sound eliciting TTS in 

pinnipeds. Based on the results for nonpulse sound, plus the known tendency in other mammals for lower 

TTS thresholds with impulse than with nonpulse sound, the TTS thresholds for pinnipeds exposed to 

impulse sound may be as low as 171 dB re 1 μPa2

-s in the more sensitive species, such as the harbor seal. 

There are no specific data concerning the levels of underwater sound necessary to cause PTS in any 

species of marine mammal. However, data from terrestrial mammals provide a basis for estimating the 

difference between the (unmeasured) PTS thresholds and the measured TTS thresholds. A conservative 

(precautionary) estimate of this offset between TTS and PTS thresholds, when sound exposure is 

measured on a SEL basis (received energy levels), is to add 15 dB to the TTS value for impulsive sounds 

and 20 dB for nonpulse sounds (Southall et al., 2007). Thus, now-available data indicate that the lowest 

received levels of impulsive sounds (e.g., airgun pulses) that might elicit slight auditory injury (i.e., PTS) 

are 198 dB re 1 μPa2

-s in cetaceans (i.e., 183 + 15 dB), and 186 dB re 1 μPa2-s in the more sensitive 

pinnipeds (i.e., 171 + 15 dB). Corresponding values for nonpulse sounds (e.g., boomers, side-scan 

sonars, chirp subbottom profilers, and single beam or multibeam depth sounders) are 215 re 1 μPa2

-s in 

cetaceans (i.e., 195 + 20 dB) and 203 dB re 1 μPa2

-s in the more sensitive pinnipeds (e.g., 183 + 20 dB) 

(Southall et al., 2007). These SEL measures are all assumed to be taken using M-weighting; i.e., 

somewhat down-weighting the energy for frequencies near and especially beyond the lower and upper 

frequency limits of hearing in the relevant marine mammal group (Southall et al., 2007). 
E-6 Atlantic G&G Programmatic EIS

The noise criteria group also concluded that receipt of an instantaneous flat-weighted peak pressure 

exceeding 230 dB re 1 μPa (peak) for cetaceans or 218 dB re 1 μPa (peak) for pinnipeds might also lead 

to auditory injury even if the aforementioned cumulative energy-based criterion was not exceeded 

(Table E-2). 

The primary measure of sound used in the proposed new criteria is the received sound energy, not just 

in the single strongest pulse, but accumulated over time. The most appropriate interval over which the 

received airgun signal should be accumulated is not well defined. However, pending the availability of 

additional relevant information, the noise criteria group has suggested considering noise exposure over 

24-hour (hr) periods. 

Included in Southall et al. (2007) is a discussion and proposed application of M-weighting, which 

would be used to adjust a species’ threshold slightly in order to account for its relative sensitivity to 

signals at various frequencies. M-weighting was used as described in Appendix D. 

Table E-2 

 

Injury and Behavioral Disturbance Exposure Criteria for Cetaceans and Pinnipeds, 

as proposed by Southall et al. (2007) 

Level A (Injury) Level B (Behavioral Disturbance) 

Group Pressure 

(dB re 1 μPa RMS) 

(peak) (flat) 

Energy 

(dB re 1 μPa2-s) 

Pressure 

(dB re 1 μPa RMS) 

Multiple Pulsed Signals/Systems 

Low-frequency Cetaceans 230 198 * 

Mid-frequency Cetaceans 230 198 * 

High-frequency Cetaceans 230 198 * 

Pinnipeds (in water) 218 186 * 

Nonpulsed Signals/Systems 

Low-frequency Cetaceans 230 215 * 

Mid-frequency Cetaceans 230 215 * 

High-frequency Cetaceans 230 215 * 

Pinnipeds (in water) 218 203 * 

* = not specified in Southall et al., 2007. 

3.1.2. Behavioral Disturbance Criteria 

As noted above, the existing NMFS criterion for potential behavioral disturbance to marine mammals 

from airgun-based seismic surveys is 160 dB re 1 μPa (RMS). The noise criteria group concluded that 

available data are insufficient as a basis for recommending any specific alternative behavioral disturbance 

criteria applicable to multiple-pulse sounds like airgun array sounds (Southall et al., 2007). Behavioral 

reactions to acoustic exposure are generally more variable, context-dependent, and less predictable than 

effects of noise exposure on hearing or physiology (Southall et al., 2007). There is no consensus on the 

appropriate noise exposure metric for assessing behavioral reactions, and it is recognized that many 

variables other than exposure level affect the nature and extent of responses to a particular stimulus 

(Southall et al., 2007). Finally, it is often difficult to differentiate brief, minor, biologically unimportant 

reactions from profound, sustained, and/or biologically meaningful responses related to growth, survival, 

and reproduction (NRC, 2005; Southall et al., 2007; Ellison et al., 2011). Therefore, in the Programmatic 

EIS, only the 160 dB criterion was used for the calculation of Level B incidental takes. This criteria 

applies to both multiple pulse signals/systems including: (1) the large (5,400 cubic inch) seismic airgun 

array and (2) the small (90 cubic inch) airgun array; as well as the nonpulsed electromechanical 

sources/systems including (1) boomers, (2) multibeam depth sounders, (3) side-scan sonars, and (4) chirp 

subbottom profilers. The justification for the use of this criterion for the seismic airgun sources is that it 

has historic precedent. For the nonpulse systems, this threshold has also been historically used for 

nonpulsed systems and even extended to continuous nonpulsed systems. Even though these systems are 

not technically “continuously” transmitting, they can transmit very short signals (i.e., signals that are tens 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-7 

of thousandths to tenths of a second long) every second but in different beams or frequencies. 

Additionally, it should be pointed out that many of the transmission frequencies of these nonpulsed 

systems are greater than 200 kilohertz (kHz), and therefore are above the hearing spectrum of nearly all of 

the marine species, with the exception of the harbour porpoise. Thus, the use of the 160 dB SPL criterion 

for the Level B threshold for both the multiple pulsed and nonpulsed systems is a reasonable combination 

of the historic values used and best current science and precedents available. Other methodologies, 

including the possible use of a risk continuum function as was used in the Surveillance Towed Array 

Sensor System (SURTASS) Low-Frequency Active (LFA) Sonar Final Environmental Impact Statement 

(FEIS) and Final Supplemental Environmental Impact Statement (FSEIS) (U.S. Dept. of the Navy, 2001, 

2007a) are being examined for Level B impact assessment for various sources at this time, but none has 

been applied to the impact analysis for this Programmatic EIS. 

Acoustic impact criteria applicable to other types of biota are less well-developed than the criteria for 

cetaceans and pinnipeds. There is an ongoing effort to develop science-based criteria for fish and sea 

turtles. 

4. ACOUSTIC SOURCE MODELING 

A detailed discussion of acoustic sources, including both airguns and electromechanical sources, as 

well as how they were modeled acoustically, can be found in Appendix D. Sources modeled in 

Appendix D include a large (5,400 cubic inch) airgun array, small (90 cubic inch) airgun array, boomer, 

side-scan sonar, chirp subbottom profiler, and multibeam depth sounder. 

5. AREA ACOUSTIC PROPAGATION CHARACTERIZATION 

5.1. GENERAL CHARACTERIZATION OF ALL OPERATIONAL AREAS

This section discusses the methodology used to characterize the underwater acoustic propagation 

environment of the Area of Interest (AOI) (Figure E-1) for propagation modeling to be used for impact 

analysis of underwater acoustic source transmissions. This characterization attempts to eliminate the need 

to account for existing environmental features that do not impact the final analysis while maintaining an 

adequate representation of the environment of the AOI that impacts the analysis. The characterization 

was conducted in two parts. First, the sound speed environment was sorted into areas of like propagation 

for each of the four seasons. Second, bottom sediments were examined and classified as two sub-areas to 

account for the different acoustic bottom loss areas expected in the study. The two parts were then 

combined to yield defined subareas of unique propagation modes and bottom loss. 
E-8 Atlantic G&G Programmatic EIS

Figure E-1. Area of Interest (black line) Plotted over Bathymetry from the 

Digital Bathymetric Data Base Variable Resolution Database 

(depth in feet). 

5.1.1. Propagation 

Available sound speed profile databases were evaluated to find an appropriate database to use that 

contained data for the AOI throughout the year. The Provinced (GDEM) monthly sound speed database 

was selected to characterize the sound speed environment of the deep water modeling regions 

(water depths greater than 1,000 ft). The Provinced GDEM database represents the AOI using 13 sound 

speed areas or provinces and groups like-sound speed profiles in provinces for each month of the year 

(Figure E-2). This database does not have a shallow water component. The GDEM Variable Resolution 

(GDEM_V) database was selected to characterize the sound speed environment of the shallow water 

regions (water depths less than 305 m [1,000 ft]). The GDEM_V database was interrogated at a 

15-minute spacing to yield sound speed profiles in the shallow water portion of the AOI for water depth 

from 9 to 305 m (30 to 1,000 ft). 

Figure E-2. Provinced Generalized Digital Environmental Model (GDEM) 

Areas within the Area of Interest (black line). 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-9 

Profiles were examined from each database using the months presented in Table E-3 to represent 

each season. To eliminate the redundant effort needed to conduct impact analysis on each sound speed 

profile extracted for the AOI, each profile was examined and grouped into areas of similar acoustic 

propagation and therefore similar acoustic impact. The acoustic propagation was modeled for each 

profile, for each season, using a standard raytrace model. An acoustic raytrace will show the propagation 

path for acoustic energy as it travels from a source and through the water. The representative sound 

source used for this raytrace modeling was omni-directional at a depth of 6 m (20 ft). The propagation 

paths were modeled by computing all ray paths (±90°) of the acoustic energy along an environmentally 

range-independent radial (one sound speed profile and a flat bottom) for each profile and each season. 

Table E-3 

 

Month Used to Represent Each Season in Sound Speed Database Extraction 

Season Representative Month 

Winter February 

Spring May 

Summer August 

Fall November 

The raytraces for each season were examined and grouped into like propagation areas which yielded 

areas with similar acoustic propagation for both shallow and deep water areas. The distinguishing 

characteristics of acoustic propagation paths in the AOI can be grouped into the following: 

1. Presence of a Surface Duct 

The presence or absence of a surface layer that trapped some energy from a shallow 

source depth is the first discriminator of propagation characteristics. A surface layer that 

traps acoustic energy is also called a surface duct. A surface duct occurs when the sound 

speed increases with depth from the surface to a depth below the source depth. Generally 

this occurs in colder seasons where colder air temperature and higher winds cool and mix 

waters in the surface layer. Surface ducts can also occur when water masses of different 

densities mix, such as north-flowing Gulf Stream water mixing with south-flowing North 

Atlantic waters. The acoustic ray paths trapped in the surface duct do not hit the bottom, 

but are either turned upward to reflect off the surface over-and-over (Figure E-3) or 

turned downward to be trapped again. Not all transmitted acoustic energy is trapped in a 

surface duct. In fact, most transmitted energy from shallow source in a surface duct is 

reflected off the bottom. But surface layer trapped energy propagations with less loss 

than bottom bounce paths, therefore increasing the potential range of impact of the 

transmitted acoustic energy from the source. 
E-10 Atlantic G&G Programmatic EIS

Figure E-3. Example of Surface Layer Trapped Acoustic Energy. 

2. Strength of the Surface Duct 

If a surface layer is present, the relative amount of acoustic angles that are trapped in the 

surface duct is the next discriminator of propagation characteristics. Generally, the 

deeper the surface layer, the more acoustic angles are trapped in the layer; additional 

angles can be trapped if the gradient of sound speed is greater, but this is not seen in the 

AOI. The more acoustic source angles trapped in the surface duct, the more energy is 

transmitted from the source to the surrounding environment without attenuation from 

bottom reflection and therefore have more potential to effect the environment. 

3. Presence of a Convergence Zone 

The third discriminator of propagation characteristics is the presence of a Convergence 

Zone (CZ). The CZ propagation only occurs in very deep water where the sound speed 

eventually increases with great depth (due to pressure) and the deep-going acoustic 

propagation rays are bent back toward the surface (Figure E-4). These deep-going rays 

will travel back to the source depth (usually at a range of 30-40 nmi from the source) and 

turn toward the deep again or be reflected off the surface and travel deep again. The 

deeper the water depth, more rays will travel in the CZ. These deep-going rays travel a 

relatively great distance without reflection off the bottom and without the corresponding 

reflection loss. The water depth needed for a CZ to occur varies with the season and the 

depth of the source. If the source depth is constant, the water depth needed increases 

with warmer seasons. The presence of a CZ will support propagation of acoustic energy 

to relatively long distances without attention of bottom reflection and could increase the 

potential to effect the environment at a relatively long range. The presence or absents of 

surface ducts is independent of CZ propagation. 

Surface layer trapped 

acoustic energy
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-11 

Figure E-4. Example of the Convergence Zone Propagation. 

4. Bottom Bounce Paths 

The last acoustic propagation discriminator, and the most dominate in the AOI, is total 

bottom bounce propagation. Total bottom bounce propagation is not trapped in a surface 

layer nor CZ propagated, but travels downward from the source to reflect off the bottom. 

The amount of acoustic energy reflected off the bottom back into the water is dependent 

on the composition of the bottom. A rocky bottom reflects more energy back into the 

water than a muddy bottom. Therefore, the bottom composition must be considered 

when estimating the environmental impact of bottom bounce acoustic energy that is of 

sufficient strength to contribute to the environmental impact. 

5.1.1.1. Winter 

The acoustic propagation environment of the AOI in winter can be characterized with a single profile 

for deep water areas and two unique sound speed profiles for shallow water areas. The winter profile 

from GDEM Province 180 is selected to represent all deep water areas (>305 m [1,000 ft]) of the AOI. 

This profile supports only shallow angles in ducted propagation, but does support CZ propagation in 

water depths greater than 4,267 m (14,000 ft). Therefore, there are four unique types used to characterize 

winter propagation in the AOI (Figure E-5): 

Convergence Zone
E-12 Atlantic G&G Programmatic EIS

Figure E-5. Winter Propagation Characteristics of the Area of 

Interest (black line). 

1. Deep Water CZ propagation, represented by GDEM Province 180/February, for 

water depths greater than 4,267 m (14,000 ft) in the AOI. The representative location 

for this propagation type is 32-00° N/72-00° W. Only acoustic energy transmitted at 

shallow angles (0° to ±1°) from the source is trapped in the surface duct, if any. Steep 

source angles are transmitted into the bottom. Source angles between ±1° and ±6° 

(or more depending on water depth) are converted to CZ propagation. 

2. Deep Water Bottom Bounce propagation, represented by GDEM Province 

180/February, for water depths greater than 305 m (1,000 ft), but less than 4,267 m 

(14,000 ft), in the AOI. The representative location for this propagation type is 

32-45°N/76-00°W. Only acoustic energy transmitted at shallow angles (0° to ±1°) 

from the source is propagated in the surface duct, if any. All other source angles are 

transmitted into the bottom. 

3. Southern Shallow Waters, represented by the GDEM February profile at 

30-30° N/80-15° W, for water depths less than 1,000 ft (305 m) and south of 

31-30° N. Only acoustic energy transmitted at shallow angles (0° to ±1°) from the 

source is propagated in the surface duct, if any. All other source angle paths are 

transmitted into the bottom. 

4. Northern Shallow Waters, represented by the GDEM February profile at 

36-15° N/74-45° W, for water depths less than 305 m (1,000 ft) and north of 

31-30°N. This profile traps a moderate amount of acoustic energy in the surface 

duct. At least ±2° of source energy paths are trapped in the surface layer, but 

generally ±4° are trapped. All other source angle paths are transmitted into the 

bottom. 

5.1.1.2. Spring 

The acoustic propagation environment of the AOI in spring can be characterized with a single profile 

for deep water areas and two unique sound speed profiles for shallow water areas. The spring profile 

from GDEM Province 156 is selected to represent all deep water areas of the AOI. This profile supports 

only shallow angles in ducted propagation, but does support CZ propagation in water depths greater than 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-13 

4,267 m (14,000 ft). Therefore there are four unique types used to characterize spring propagation in the 

AOI (Figure E-6): 

Figure E-6. Spring Propagation Characteristics of the Area of 

Interest (black line). 

1. Deep Water CZ propagation, represented by GDEM Province 156/May, for water 

depths greater than 4,267 m (14,000 ft) in the AOI. The representative location for 

this propagation type is 32-00° N/72-00° W. Only acoustic energy transmitted at the 

shallowest angles from the source is propagated in the surface duct, if any. Steep 

source angles are transmitted into the bottom. Source angles between ±1° and ±4° 

(or more, depending on water depth) are converted to CZ propagation. 

2. Deep Water Bottom Bounce propagation, represented by GDEM Province 156/May, 

for water depths greater than 305 m (1,000 ft), but less than 4,267 m (14,000 ft), in 

the AOI. The representative location for this propagation type is 31-30° N/75-00° W. 

Only acoustic energy transmitted at the shallowest angles from the source is trapped 

in the surface duct, if any. All other source angles are transmitted into the bottom. 

3. Bottom Bounce Shallow Waters, represented by the GDEM May profile at 

32-00° N/79-15° W, for water depths less than 305 m (1,000 ft, south of 34-30° N or 

north of 36-00° N. Only acoustic energy transmitted at shallow angles (0° to ±1°) 

from the source is trapped in the surface duct, if any. All other source angles paths 

are transmitted into the bottom. 

4. Moderately-ducted (Outer Banks) Shallow Waters, represented by the GDEM May 

profile at 35-00° N/76-15° W, for water depths less than 305 m (1,000 ft), between 

36-00° N and 34-30° N. This area is roughly the Outer Banks area of North Carolina. 

This profile traps a moderate amount of acoustic energy in the surface duct. At least 

±2° of source energy paths are trapped in the surface duct, but generally ±4° are 

trapped. All other source angle paths are transmitted into the bottom. 

5.1.1.3. Summer 

The acoustic propagation environment of the AOI in summer can be characterized with a single 

profile for deep water areas and one sound speed profile for shallow water areas. The summer profile 

from GDEM Province 156 is selected to represent all deep water areas of the AOI. This profile supports 
E-14 Atlantic G&G Programmatic EIS

only the shallowest angle in ducted propagation, but does support CZ propagation in water depths greater 

than 4,877 m (16,000 ft). The depth of CZ propagation has increased from spring because of surface 

warming of waters in the AOI. There are three unique types used to characterize summer propagation in 

the AOI (Figure E-7): 

Figure E-7. Winter Propagation Characteristics of the Area of Interest 

(black line). 

1. Deep Water CZ propagation, represented by GDEM Province 156/August, for water 

depths greater than 4,877 m (16,000 ft) in the AOI. The representative location for 

this propagation type is 32-00° N/72-00° W. Only acoustic energy transmitted at the 

shallowest angles from the source is propagated in the surface duct, if any. Steep 

source angles are transmitted into the bottom. Source angles between ±1° and ±4° 

(or more depending on water depth) are converted to CZ propagation. 

2. Deep Water Bottom Bounce propagation, represented by GDEM Province 

156/August, for water depths greater than 305 m (1,000 ft), but less than 4,877 m 

(16,000 ft), in the AOI. The representative location for this propagation type is 

31-30° N/75-00° W. Only acoustic energy transmitted at the shallowest angles from 

the source is propagated in the surface duct, if any. All other source angles are 

transmitted into the bottom. 

3. Shallow Waters, represented by the GDEM August profile at 36-00° N/74-45° W, for 

water depths in water depths less than 305 m (1,000 ft). Only acoustic energy 

transmitted at the shallowest angle from the source is propagated in the surface duct, 

if any. All other source angle paths are transmitted into the bottom.

5.1.1.4. Fall 

Fall is the most complex season for underwater sound propagation characterization within the AOI. 

The southern portion of the AOI still exhibits summer-like propagation while the northern portion has 

transitioned toward winter-like propagation. The acoustic propagation environment of the AOI in fall is 

characterized by two deep water areas and two shallow water areas. Each of the deep water areas support 

either bottom bounce or CZ propagation. There are six unique propagation types used to characterize fall 

propagation in the AOI (Figure E-8): 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-15 

Figure E-8. Fall Propagation Characteristics of the Area of Interest 

(black line). 

1. Northern Deep Water CZ propagation, represented by GDEM Province 

142/November, for water depths greater than 3,810 m (12,500 ft) in the AOI. The 

representative location for this propagation type is 36-30° N/71-30° W. Only 

acoustic energy transmitted at shallow angles (0°-±2°) from the source is propagated 

in the surface duct. Steep source angles are transmitted into the bottom. The narrow 

range of source angles between ±2° and ±4° (or more depending on water depth) are 

converted to CZ propagation. 

2. Northern Deep Water Bottom Bounce propagation, represented by GDEM Province 

142/November, for water depths greater than 305 m (1,000 ft), but less than 3,810 m 

(12,500 ft), in the AOI. The representative location for this propagation type is 

36-30° N/72-30° W. Only acoustic energy transmitted at shallow angles (0°- ±2°) 

from the source is propagated in the surface duct. All other source angles are 

transmitted into the bottom. 

3. Southern Deep Water CZ propagation, represented by GDEM Province 

156/November, for water depths greater than 4,115 m (13,500 ft) in the AOI. The 

representative location for this propagation type is 29-30° N/75-30° W. Only 

acoustic energy transmitted at the shallowest angles from the source is propagated in 

the surface duct, if any. Steep source angles are transmitted into the bottom. The 

narrow range of source angles between ±2° and ±4° (or more depending on water 

depth) are converted to CZ propagation. 

4. Southern Deep Water Bottom Bounce propagation, represented by GDEM Province 

156/November, for water depths greater than 305 m (1,000 ft), but less than 4,115 m 

(13,500 ft), in the AOI. The representative location for this propagation type is 

31-00° N/75-30° W. Only acoustic energy transmitted at the shallowest angles from 

the source is propagated in the surface duct, if any. All other source angles are 

transmitted into the bottom. 

5. Southern Shallow Waters, represented by the GDEM November profile at 

32-00° N/79-15° W, for water depths in water depths less than 305 m (1,000 ft) and 

areas south of 34-30° N. Only acoustic energy transmitted at the shallowest angle 

from the source is propagated in the surface duct, if any. All other source angle paths 

are transmitted into the bottom. 
E-16 Atlantic G&G Programmatic EIS

6. Northern Shallow Waters, represented by the GDEM November profile at 

36-30° N/74-45° W, for water depths in water depths less than 305 m (1,000 ft) and 

areas northern of 34-30° N. A moderate amount of acoustic energy is trapped in the 

surface duct for source angle transmitted up to ±5°. All other source angle paths are 

transmitted into the bottom. 

5.1.2. Bottom Loss 

The above work shows that a great deal of acoustic energy transmitted in the AOI will reflect off the 

bottom. In addition, the nature of the intended acoustic work will “aim” the transmitted energy toward 

the bottom. Therefore, acoustic bottom loss should be considered to evaluate the impact of transmitted 

acoustic energy in the AOI. 

Bottom loss is dependent on the type of sediment that reflects the acoustic energy, along with the 

frequency of the sound reflecting off the bottom and the angle that the sound reflects off the bottom. This 

study assumes that frequency and angle do not change with location and examines changes in sediment 

type over location to understand the bottom loss in the AOI. More than 10,000 observations from the 

National Geophysical Data Center (NGDC) Surficial Sea Floor Sediment database were used to 

characterize sediments in the study. Bottom sediment grain size index was assigned to each observation 

(Table E-4) according to the University of Washington Applied Physics Laboratory Technical Report 

9407 on bottom loss modeling (University of Washington Applied Physics Laboratory, 1994). 

The results of the above processing yielded an irregularly spaced dataset of observation location and 

grain size throughout the AOI. This dataset was used to create a 1 nmi spacing grid to represent the 

geographic distribution of grain size for the AOI by using the closest measured data for each grid point 

(Figure E-9). 

Fine grain sediment, such as clays (with high grain size index) can be seen to dominate the areas of 

water depth greater than 1,219 m (4,000 ft). Coarser sediments, such as sand and gravel (lower grain size 

index) can be seen to dominate areas of water depth less than 1,219 m (4,000 ft). Bottom loss curves 

were computed with the Rayleigh Bottom Loss Model using the dominate grain size indexes seen in the 

AOI (Figure E-10). 

A mix of gravels and sands dominate the sediment types in water depths less than 1,219 m (4,000 ft). 

These corresponding grain size indexes (-1 and 1) result in very similar bottom loss curves (Figure E-10). 

The difference seen is insignificant when considering impact analysis. A grain size index of -1 is selected 

to represent the sediment for areas of water depth less than 1,219 m (4,000 ft). The bottom loss for a 

-1 grain size index is less, resulting in more energy reflected back into the water column, and therefore is 

the worst case for impact analysis. 

Bottom loss in deep water areas has little effect on impact analysis because results are driven by the 

direct path propagation from the source directly to the animal. Propagation losses of the sound traveling 

to the bottom and back are very high compared to direct path losses. In water depths greater than 1,219 m 

(4,000 ft), spherical spreading loss of acoustic energy traveling from a near-surface source to the bottom 

and back to the near surface is at least 67 dB. Therefore efforts to model the details of different bottom 

loss regions in deep water would have no consequence in impact analysis. A sediment grain size index of 

7 is therefore used characterized areas of water depth greater than 1,219 m (4,000 ft). 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-17 

Table E-4 

 

Grain Size Index for Sediment Type 

Sediment Type Bottom Sediment Grain Size Index 

Rough Rock -9.0 

Rock -7.0 

Cobble -3.0 

Gravel -3.0 

Pebble -3.0 

Sandy Gravel -1.0 

Very Coarse Sand -0.5 

Muddy Sandy Gravel 0.0 

Coarse Sand 0.5 

Gravelly Sand 0.5 

Gravelly Muddy Sand 1.0 

Sand 1.5 

Medium Sand 1.5 

Muddy Gravel 2.0 

Fine Sand 2.5 

Silty Sand 2.5 

Muddy Sand 3.0 

Very Fine Sand 3.5 

Clayey Sand 4.0 

Coarse Silt 4.5 

Sandy Silt 5.0 

Medium Silt 5.5 

Sand-Silt-Clay 5.5 

Silt 6.0 

Sandy Mud 6.0 

Fine Silt 6.5 

Clayey Silt 6.5 

Sandy Clay 7.0 

Very Fine Silt 7.5 

Silty Clay 8.0 

Clay 9.0 
E-18 Atlantic G&G Programmatic EIS

Figure E-9. Grain Size Index for the Area of Interest. 

Figure E-10. Rayleigh Bottom Loss Estimates for Grain Size Index 7, 1, and -1. 

5.1.3. General Characterization Summary 

Combining the defined area of sound speed profiles and bottom sediments presented above results in 

a definition of 21 unique propagation modes and bottom loss regions in the AOI. These 21 modeling 

regions are defined in Table E-5 and cover all four seasons. Each region is intended to define one sound 

speed profile and grain size index to be used for each transmission loss (TL) model run to be used for 

impact analysis. The SVPs used for this characterization are specified in Table E-6. The resulting 

seasonal plots show these 21 modeling regions (Figures E-11 through E-14). 

This study defines the change between shallow and deep sound speed environments at 305 m 

(1,000 ft) water depth. This is because the deep water database of sound speed does not extend into water 

depths less than 305 m (1,000 ft). This study also defined a change in the sediment type at 1,219 m 

Grain Size 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-19 

(4,000 ft) water depth. This change is defined from direct observation of the sediment grain size data. 

Where appropriate, a unique propagation/sediment region has been assigned to this area between 

305-1,219 m (1,000-4,000 ft) of water depth. This is especially true for the Blake Plateau areas of the 

southern portion of the AOI, south of 33-30° N (Figure E-1). However, north of 33-30° N, the distance 

between the 305 m and 1,219 m (1,000 ft and 4,000 ft) isobaths is a relatively small area; no distinction 

has been drawn between areas defined by the these isobaths north of 33-30° N. This can be seen in the 

water depth definition of the Fall Northern Deep Bottom Bounce area. 
E-20 Atlantic G&G Programmatic EIS

Table E-5 

 

Summary of Propagation and Bottom Loss Characterization in the Area of Interest 

Modeling 

Region Season Propagation Characterization 

Water 

Depth 

(kft) 

GDEM Profile Representative 

Location Sediment

Grain 

Size 

Index 

1 Winter Convergence Zone >14 Province 

180/February 

32-00N 

72-00W Clay 7 

2 Winter Bottom Bounce (Clay) 4-14 Province 

180/February 

32-45N 

76-00W Clay 7 

3 Winter Bottom Bounce (Sand) 1-4 Province 

180/February 

31-00N 

78-00W Sand -1 

4 Winter Southern Shallow 

Water <1 

February @ 

representative 

location 

30-30N 

80-15W Sand -1 

5 Winter Northern Shallow 

Water <1 

February @ 

representative 

location 

36-15N 

74-45W Sand -1 

6 Spring Convergence Zone >14 Province 156/May 32-00N 

72-00W Clay 7 

7 Spring Bottom Bounce (Clay) 4-14 Province 156/May 31-30N 

75-00W Clay 7 

8 Spring Bottom Bounce (Sand) 1-4 Province 156/May 31-00N 

78-00W Sand -1 

9 Spring Bottom Bounce 

Shallow Water <1 

May @ 

representative 

location 

32-00N 

79-15W Sand -1 

10 Spring 

Moderately-ducted 

(Outer Banks) shallow 

water 

<1 

May @ 

representative 

location 

35-00N 

76-15W Sand -1 

11 Summer Convergence Zone >16 Province 

156/August 

32-00N 

72-00W Clay 7 

12 Summer Bottom Bounce (Clay) 4-16 Province 

156/August 

31-30N 

75-00W Clay 7 

13 Summer Bottom Bounce (Sand) 1-4 Province 

156/August 

31-00N 

78-00W Sand -1 

14 Summer Shallow Water <1 

August @ 

representative 

location 

36-00N 

74-45W Sand -1 

15 Fall Northern Convergence 

Zone >12.5 Province 142/November 

36-30N 

71-00W Clay 7 

16 Fall Northern Deep Bottom 

Bounce 1-12.5a Province 142/November 

36-30N 

72-00W Clay 7 

17 Fall Southern Convergence 

Zone >13.5 Province 156/November 

29-30N 

75-30W Clay 7 

18 Fall Southern Deep Bottom 

Bounce (Clay) 4-13.5 Province 

156/November 

31-00N 

75-30W Clay 7 

19 Fall Southern Deep Bottom 

Bounce (Sand) 1-4 Province 

156/November 

31-00N 

78-00W Sand -1 

20 Fall Southern Shallow 

Water <1 

November @ 

representative 

location 

32-00N 

79-15W Sand -1 

21 Fall Northern Shallow 

Water <1 

November @ 

representative 

location 

36-30N 

74-45W Sand -1 

a

 Note: In the Fall Northern Deep Bottom Bounce sub-area, the area defined by the 305 m and 1,219 m (1,000 ft and 4,000 ft) 

isobaths, occurs on the shelf break and occupies a relatively small area, therefore this sub-area is re-defined as starting at 305 m 

(1,000 ft) water depth. 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-21 

Table E-6 

 

Summary Table of the Sound Velocity Profiles Used in the Characterization of the Area 

Sound Velocities (m/s) 

 Modeling Regions 

Depth 

(m) 1,2,3 4 5 6,7,8 9 10 11,12,13 14 15,16 17,18, 19 20 21 

0 1532.9 1527.3 1524.6 1533.7 1532.6 1529.3 1544.3 1533.6 1524.7 1529.3 1516.2 1535.5 

2 1527.4 1524.6 1532.6 1529.5 1533.7 1516.3 1535.6 

4 1527.4 1524.6 1532.5 1529.7 1533.8 1516.4 1535.7 

6 1527.5 1524.6 1532.5 1529.9 1533.8 1516.5 1535.7 

8 1527.5 1524.6 1532.5 1530.2 1533.9 1516.6 1535.7 

10 1533.1 1527.6 1524.6 1533.8 1532.5 1530.5 1544.5 1533.8 1524.9 1529.5 1516.7 1535.7 

15 1527.8 1524.5 1532.4 1531.3 1532.5 1517.4 1535.7 

20 1533.3 1527.8 1524.5 1533.6 1532.3 1531.8 1544.3 1530.3 1525.1 1529.6 1517.6 1535.7 

25 1527.7 1524.4 1531.9 1531.9 1527.5 1517.2 1535.7 

30 1533.4 1527.7 1524.3 1532.9 1531.4 1531.9 1543.0 1524.5 1525.2 1529.8 1516.5 1535.6 

35 1527.5 1524.1 1530.8 1531.7 1522.2 1515.1 1535.5 

40 1527.3 1523.8 1530.2 1531.3 1519.7 1513.3 1535.4 

45 1527.0 1523.6 1529.4 1531.0 1517.4 1511.4 1535.1 

50 1533.6 1526.8 1523.3 1530.4 1528.7 1530.5 1536.4 1515.5 1525.6 1530.1 1509.8 1534.8 

55 1526.4 1523.0 1528.1 1530.0 1514.5 1509.4 1534.4 

60 1526.1 1522.6 1527.4 1529.4 1513.8 1509.2 1534.0 

65 1525.7 1522.2 1526.7 1528.8 1513.1 1508.9 1533.4 

70 1525.2 1521.7 1525.9 1528.1 1512.5 1508.7 1532.7 

75 1533.4 1524.7 1521.2 1528.1 1525.1 1527.4 1531.1 1512.0 1525.8 1530.2 1508.5 1531.9 

80 1524.1 1520.7 1524.4 1526.8 1511.6 1508.4 1530.9 

85 1523.5 1520.2 1523.6 1526.1 1511.4 1508.3 1529.8 

90 1522.8 1519.7 1522.9 1525.5 1511.3 1508.2 1528.5 

95 1522.2 1519.1 1522.1 1524.9 1511.0 1508.0 1527.3 

100 1532.0 1521.4 1518.5 1527.3 1521.2 1524.3 1529.8 1510.7 1525.4 1529.6 1507.9 1526.1 

110 1520.0 1517.4 1519.6 1523.2 1509.9 1507.4 1523.8 

120 1518.4 1516.2 1517.9 1522.0 1509.0 1506.9 1521.6 

125 1529.9 1527.0 1529.0 1524.3 1528.2 

130 1516.8 1514.9 1516.2 1521.0 1508.2 1506.3 1519.3 

140 1515.0 1513.5 1514.4 1520.0 1507.3 1505.7 1517.3 

150 1527.9 1513.3 1512.0 1526.6 1512.7 1519.0 1528.0 1506.4 1522.7 1526.7 1505.1 1515.3 

160 1511.6 1510.5 1511.1 1518.0 1505.6 1504.3 1513.5 

170 1509.8 1509.1 1509.6 1517.1 1504.7 1503.5 1511.6 

180 1508.0 1507.7 1508.1 1516.1 1503.7 1502.6 1509.8 

190 1506.1 1506.3 1506.6 1515.2 1502.8 1501.7 1508.1 

200 1526.2 1504.9 1525.8 1505.2 1514.4 1525.9 1501.9 1520.1 1525.2 1500.9 1506.6 

220 1502.5 1502.8 1512.8 1500.0 1499.0 1504.0 

240 1500.2 1500.5 1511.2 1498.1 1497.2 1501.7 

250 1525.0 1525.1 1524.1 1519.0 1524.7 

260 1498.0 1498.5 1509.7 1496.3 1495.4 1499.5 

280 1496.1 1496.6 1508.3 1494.6 1493.8 1497.4 

300 1523.9 1494.3 1524.2 1495.0 1506.9 1522.8 1493.1 1518.1 1524.0 1492.2 1495.5 

350 1503.8 1489.7 1488.5 

400 1521.1 1522.4 1522.4 1515.1 1522.4 1485.4 

500 1518.4 1520.8 1520.8 1512.3 1520.8 1481.1 

600 1514.5 1517.7 1517.7 1508.6 1517.7 1480.0 

700 1508.8 1512.2 1512.2 1503.8 1512.2 1480.3 

800 1502.9 1506.1 1506.1 1499.2 1506.1 1481.1 

900 1497.7 1500.1 1500.1 1495.1 1500.1 1482.3 

1000 1493.6 1495.1 1495.1 1492.0 1495.1 

1100 1491.0 1491.7 1491.7 1490.0 1491.7 

1200 1489.9 1490.0 1490.0 1489.3 1490.0 

1300 1490.1 1489.9 1489.9 1489.5 1489.9 

1400 1491.1 1490.9 1490.9 1490.5 1490.9 

1500 1492.6 1492.6 1492.6 1492.0 1492.6 

1750 1495.9 1496.3 1496.3 1495.7 1496.3 

2000 1499.0 1499.5 1499.5 1499.2 1499.5 

2500 1505.3 1505.7 1505.7 1505.7 1505.7 

3000 1512.0 1512.0 1512.0 1512.4 1512.0 

4000 1527.6 1527.4 1527.4 1527.8 1527.4 

5000 1545.2 1545.2 1545.2 1545.0 1545.2 

6000 1562.6 1562.6 1562.6 1561.8 1562.6 
E-22 Atlantic G&G Programmatic EIS

Figure E-11. Final Modeling Regions for the Winter. 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-23 

Figure E-12. Final Modeling Regions for the Spring. 
E-24 Atlantic G&G Programmatic EIS

11

Figure E-13. Final Modeling Regions for the Summer. 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-25 

Figure E-14. Final Modeling Regions for the Fall. 
E-26 Atlantic G&G Programmatic EIS

5.2. SHALLOW WATER MODELING FOR MARINE MINERALS AND RENEWABLE 

ENERGY

The characterization of the acoustic propagation conducted in the previous section was designed to 

capture the variability and the general sound field structure produced by large and small airgun arrays 

used in support of oil and gas exploration and development throughout the proposed areas covered by this 

Programmatic EIS. However, acoustic modeling was also conducted to address the potential impacts for 

the active acoustic sound sources (e.g., side-scan sonars, boomers, chirp subbottom profilers, and single 

or multibeam depth sounders) used in conjunction with the other two programs covered by this 

Programmatic EIS, marine minerals and renewable energy. Not only do these programs use different 

acoustic systems than those typically used in oil and gas seismic surveys (i.e., airguns are not expected to 

be used), but these programs are only conducted in water nominally 100 m (328 ft) deep or less. This, 

therefore, limits their activities to the shallowest regions of the continental shelf, which are nominally 

within about 30 nmi (56 km) from the coast. 

The location and depth of water used for these programs effectively constitutes a change in several of 

the basic assumptions made for the general characterization of the area including: (1) a significant change 

in the range of water depth covered; (2) a very large reduction in the area covered; (3) a concentration of 

the sources in waters that only allow strong and repeated interactions of the acoustic sound field with the 

ocean surface and bottom; (4) a change in signal type from multiple pulsed to nonpulse; (5) a significant 

change in the typical frequencies used by the systems; and (6) the utilization of systems using higher 

frequencies which allows finer acoustic beam patterns (and in general better special resolution of the 

areas being examined). The result of these differences was that an additional set of acoustic sites were 

added to the original 21 from the general characterization in order to examine and ensure that the 

propagation modeling in the shallow water for these two programs was adequate. 

This subsequent shallow water characterization built on the existing work by using the seven shallow 

water sites (i.e., sites # 4, 5, 9, 10, 14, 20, and 21 as shown in Table E-6), and selecting two additional 

sites near the original “representative” location for that area. These new sites would therefore have the 

same SVP and propagation characteristics, but the additional stipulation was that these sites be located in 

30 and 100 m (98 and 328 ft) water depths. By examining the propagation in these two water depths for 

each source used, the analysts would ensure that a conservative estimation of the sound propagation field 

(i.e., the larger impacts) was used in the impact analysis and that the potential for local variability in the 

bathymetry would not cause an underestimation of the potential impacts. Subsequent analysis has shown 

that variability of the impacts for all of the sources examined in this Programmatic EIS only varied a few 

percentage points (i.e., <5 percent) for the two water depths examined. Therefore, the use of the larger 

impact values were conservative, but not excessively so. 

Table E-7 provides the details of the 14 additional shallow water sites used for this characterization. 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-27 

Table E-7 

 

Summary of Details of the Sites Identified in the Shallow Water Characterization 

Modeling 

Region Season Propagation Characterization 

Water 

Depth 

(m) 

Original Region Representative 

Location Sediment 

Grain 

Size 

Index 

22 Winter Southern Shallow Water 30 4 30-33N 

80-38W Sand -1 

23 Winter Northern Shallow Water 30 5 36-10N 

75-15W Sand -1 

24 Spring Bottom Bounce Shallow 

Water 30 9 32-18N 79-31W Sand -1 

25 Spring Moderately-ducted (Outer 

Banks) Shallow Water 30 10 34-48N 75-53W Sand -1 

26 Summer Shallow Water 30 14 36-10N 

75-14W Sand -1 

27 Fall Southern Shallow Water 30 20 32-18N 

79-31W Sand -1 

28 Fall Northern Shallow Water 30 21 36-10N 

75-14W Sand -1 

29 Winter Southern Shallow Water 100 4 30-29N 

80-10W Sand -1 

30 Winter Northern Shallow Water 100 5 36-06N 

74-50W Sand -1 

31 Spring Bottom Bounce Shallow 

Water 100 9 32-00N 79-15W Sand -1 

32 Spring Moderately-ducted (Outer 

Banks) Shallow Water 100 10 34-42N 75-37W Sand -1 

33 Summer Shallow Water 100 14 36-06N 

74-50W Sand -1 

34 Fall Southern Shallow Water 100 20 32-00N 

79-15W Sand -1 

35 Fall Northern Shallow Water 100 21 36-06N 

74-50W Sand -1 

Note: These shallow water modeling regions were re-ordered after the completion of the JASCO propagation modeling and may 

be in a different order than reported by JASCO in Appendix D. This was done to: (1) mirror the order of the general 

regions these sites refine; and (2) to group the model results by depth. All subsequent impact analyses and reported take 

numbers use this re-ordered numbering assignment. 

6. MARINE MAMMAL ABUNDANCES AND DENSITIES 

At the time of this analysis, the best available marine mammal density estimates for the Western 

Atlantic Ocean, and specifically for the BOEM Mid- and South Atlantic Planning Areas were the 

U.S. Navy’s Navy Operating Area (OPAREA) Density Estimates (NODE) database (U.S. Dept. of the 

Navy, 2007b). These density estimates were based on the NMFS-Southeast Fisheries Science Center 

(SEFSC) shipboard surveys conducted between 1994 and 2006, and were derived using a model-based 

approach and statistical analysis of the existing survey data using the model DISTANCE (Buckland et al., 

2001). The outputs from the NODE database are four seasonal surface density plots of the Western 

Atlantic Ocean for each of the marine mammal species occurring there. Figure E-15 is an example of the 

fall surface density plots for the Atlantic spotted dolphins. The resolution or grid size in these plots is 

dependent on the amount of data available for each species. For a fairly common species, like the 

Atlantic spotted dolphin, the grid has a fairly high-resolution (i.e., each displayed grid box is 

approximately 10 nmi2

). Additionally, the actual density values for this species range from 0.0 (very light 

shading) to 3.6 animals per square nmi (darkest shading). The density gradations are specific to each plot, 

but the higher value for each gradation is used in the subsequent analysis. This figure has been overlaid 

with the boundaries of the seven fall acoustic model regions used in this analysis. For each of these seven 

regions, the average density was computed. The resulting densities are presented in Table E-8, for each 

species and all 21 modeling regions. 

An examination of Figure E-15 shows that the existing NODE database does not provide data for the 

entire region of this Programmatic EIS; specifically, the most seaward areas of Regions 15, 17, and 18 

show as white (i.e., no data was available). In instances like this, the general known densities were 
E-28 Atlantic G&G Programmatic EIS

extrapolated outward to cover data-less areas. In this instance, the occurrence of this species appears to 

have a strong dependency on the location of the Gulf Stream, even when it moves offshore north of Cape 

Hatteras. Therefore, the extrapolation of the near-zero densities at the eastern edge of the known data 

appears reasonable. For more pelagic species, it is also reasonable to extend their relatively higher 

offshore densities into these areas without data. 

It should be noted that while the U.S. Navy was creating the NODE database, the NMFS was 

routinely consulted on the process, provided much of the data on which the analysis is based, and 

reviewed the resulting database. Additionally, the Atlantic data was used in the FEIS for Atlantic Fleet 

Active Sonar Training (U.S. Dept. of the Navy, 2008). 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-29 

15

18

16

17

17

19

20

21

Figure E-15. Density Plot for Atlantic Spotted Dolphin for Fall based on the Navy Operating Area Density 

Estimate Database (U.S. Dept. of the Navy, 2007b). 
Table E-8 Marine Mammal Densities for the 21 Modeling Regions (U.S. Dept. of the Navy, 2007b) Modeling Regions 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 

Mysticetes Minke whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0

Sei whale 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0Bryde’s whale 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0Blue whale 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0Fin whale 0.0001 0.0001 0.0005 0.0001 0.0001 0.0001 0.0001 0.0001 0.0005 0.0001 0.0001 0.0001 0.0005 0.0001 0.0001 0.0005 0.0001 0North Atlantic right whale 0.0000 0.0000 0.0000 0.0038 0.0021 0.0000 0.0000 0.0000 0.0005 0.0005 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0Humpback whale 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0006 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0

Odontocetes Common dolphin 0.0547 0.0653 0.1808 0.0547 0.1808 0.0547 0.0653 0.1808 0.1808 0.0547 0.0547 0.0547 0.1808 0.1808 0.0547 0.1914 0.0547 0

Pygmy killer whale 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0Short-finned pilot whale 0.0084 0.0826 0.1505 0.0018 0.0021 0.0025 0.0527 0.1490 0.0878 0.0019 0.0012 0.0527 0.0914 0.0296 0.0527 0.0100 0.0024 0Long-finned pilot whale 0.0028 0.0207 0.0191 0.0000 0.0005 0.0008 0.0164 0.0213 0.0125 0.0006 0.0004 0.0164 0.0131 0.0052 0.0176 0.0033 0.0008 0Risso's dolphin 0.0226 0.0451 0.0897 0.0239 0.0664 0.0014 0.0460 0.1104 0.0455 0.0005 0.0006 0.0880 0.1110 0.0447 0.0012 0.0882 0.0009 0Northern bottlenose whale 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0Pygmy sperm whale 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0.0003 0Dwarf sperm whale 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0.0008 0Atlantic white-sided dolphin 0.0017 0.0014 0.0008 0.0000 0.0013 0.0005 0.0005 0.0003 0.0003 0.0005 0.0005 0.0005 0.0003 0.0003 0.0005 0.0005 0.0005 0Fraser’s dolphin 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0Sowerby's beaked whale 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0Blainville's beaked whale 0.0000 0.0032 0.0032 0.0000 0.0000 0.0000 0.0025 0.0028 0.0000 0.0000 0.0000 0.0021 0.0014 0.0000 0.0021 0.0028 0.0000 0Gervais' beaked whale 0.0000 0.0032 0.0032 0.0000 0.0000 0.0000 0.0025 0.0028 0.0000 0.0000 0.0000 0.0021 0.0014 0.0000 0.0021 0.0028 0.0000 0True's beaked whale 0.0000 0.0032 0.0032 0.0000 0.0000 0.0000 0.0025 0.0028 0.0000 0.0000 0.0000 0.0021 0.0014 0.0000 0.0021 0.0028 0.0000 0Killer whale 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0Melon-headed whale 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0Harbor porpoise 0.0010 0.0008 0.0005 0.0000 0.0008 0.0005 0.0005 0.0003 0.0003 0.0005 0.0001 0.0001 0.0001 0.0001 0.0005 0.0005 0.0005 0Sperm whale 0.0002 0.0138 0.0182 0.0001 0.0001 0.0002 0.0138 0.0093 0.0001 0.0001 0.0001 0.0183 0.0092 0.0001 0.0092 0.0184 0.0002 0False killer whale 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0Pantropical spotted dolphin 0.0223 0.0223 0.0223 0.0223 0.0223 0.0223 0.0223 0.0223 0.0223 0.0223 0.0223 0.0223 0.0223 0.0223 0.0223 0.0223 0.0223 0Clymene dolphin 0.0106 0.0106 0.0106 0.0106 0.0106 0.0106 0.0106 0.0106 0.0106 0.0106 0.0106 0.0106 0.0106 0.0106 0.0106 0.0106 0.0106 0Striped dolphin 0.0269 0.2312 0.2312 0.0269 0.0332 0.0269 0.2092 0.0269 0.0269 0.0269 0.0269 0.0552 0.2092 0.0332 0.0495 0.2658 0.0269 0Atlantic spotted dolphin 0.0021 0.2070 0.1870 0.2918 0.3168 0.0021 0.1570 0.0880 0.2019 0.2518 0.0021 0.1870 0.1970 0.3168 0.0221 0.2469 0.0021 0Spinner dolphin 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0Rough-toothed dolphin 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0.0005 0Bottlenose dolphin 0.0179 0.0413 0.2829 0.2829 0.0647 0.0179 0.2595 0.2946 0.0296 0.0296 0.0179 0.2595 0.3764 0.2743 0.0296 0.2946 0.0179 0Cuvier's beaked whale 0.0001 0.0221 0.0222 0.0001 0.0001 0.0001 0.0173 0.0198 0.0001 0.0001 0.0001 0.0148 0.0100 0.0001 0.0148 0.0197 0.0001 0

Sirenians West Indian manatee 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0Pinnipeds Hooded seal 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0

Harbor seal 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0Gray seal 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0.0001 0
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-31 

7. IMPACT MODELING APPROACHES 

7.1. AIM MODELING AND METHODOLOGY

The AIM© is a four-dimensional (4D), individual-based, Monte Carlo-based statistical model 

designed to predict the exposure of receivers to any stimulus propagating through space and time. The 

central component of AIM is the animat movement engine, which moves the stimulus source and animal 

receivers through four dimensions (time and space) according to user inputs. AIM uses external 

range-dependent stimulus propagation models (e.g., the Marine Operations Noise Model [MONM] model 

for this modeling effort) and additional propagation models can be integrated to accommodate any class 

of propagation stimuli, including acoustic or explosive signal. 

To estimate how changing the acoustic source characteristics affects the acoustic exposure of animals, 

the AIM was utilized (Frankel et al., 2002). The AIM is strongly based on two earlier models: a whale 

movement and tracking model developed for the census of the bowhead whale (Ellison et al., 1987), and 

an underwater acoustic back-scattering model for a moving sound source in an under-ice Arctic 

environment (Bishop et al., 1987). Because the exact positions of sound sources and animals (sound 

receivers for the purpose of this analysis) in any given simulation cannot be known, multiple runs of 

realistic predictions are used to provide statistical validity. The movement and/or behavioral patterns of 

sources and receivers can be modeled based on measured field data, and these patterns can be 

incorporated into the model. Each source and/or receiver is modeled via the “animat” concept, where 

each has parameters that control its speed and direction in three dimensions. In the case of the source, it 

is also imbued with the parameters describing its source operation over time (i.e., SL, signal duration, and 

spectral characteristics). It is also possible to simulate the type of diving pattern that an animal exhibits in 

the real world. Furthermore, the movement of the animat can be programmed to respond to 

environmental factors, such as water depth and sound level (this latter feature was not used in this 

analysis). In this way, species that normally inhabit specific environments can be constrained in the 

model to stay within that habitat. 

Once the behavior of the animats has been programmed, the model is run. The run consists of a 

user-specified number of steps forward in time. For each time step, each animat is moved according to 

the rules describing its behavior. For each time step of the model run, the received sound levels at each 

receiver (i.e., each marine mammal) animat are calculated. For this analysis, AIM returns the movement 

patterns of the animats, and the received sound levels are calculated separately using the acoustic 

propagation predictions provided by JASCO (see details in Appendix D) for the different source types at 

different locations. 

At the end of each time step, each animat “evaluates” its environment, including its 3D location, the 

time, and the received sound level (if anthropogenic sound is present). If an environmental variable has 

exceeded the user-specified boundary value (e.g., water too shallow), then the animat will alter its course 

to react to the environment. These responses to the environment are entitled “aversions.” There are a 

number of potential aversion variables that can be used to build an animat’s behavioral pattern. For this 

modeling effort they primarily consisted of bathymetric aversions and modeled area boundary aversions. 

A separate simulation was created and run for each combination of location, movement pattern, and 

marine mammal species. Marine mammals were simulated by creating animats that were programmed 

with behavioral values describing dive depth, surfacing and dive durations, swimming speed, and course 

change. A minimum and maximum value for each of these parameters was specified. These data were 

extracted from the behavioral database. These data were used to simulate movements and dive 

characteristics of individual animats for each species or species group relative to the simulated vessel 

source tracks at both modeling locations. 

After the animats’ movement patterns were defined, the animats were randomly distributed over each 

simulation area. The simulation area was delineated by four boundaries composed of a combination of 

latitude and longitude lines. These boundaries extend at least one degree of latitude or longitude beyond 

the extent of the vessel track to ensure an adequate number of animats in all directions, and to ensure that 

the simulation areas extended beyond the area where substantial behavioral reactions might be 

anticipated. Each simulation had approximately 4,000 animats representing each species. In most cases, 

this represents a higher density of animats in the simulation (0.1 animats/km2

) than occurs in the real 

environment. This “over-population” allowed the calculation of smoother distribution tails and in the 
E-32 Atlantic G&G Programmatic EIS

final analysis, all results were normalized back to actual predicted population counts by species. During 

the AIM modeling, animats were programmed to remain within the simulation area boundaries. This 

behavior was incorporated to prevent the animats from diffusing out of the simulation, the result of which, 

if allowed, would be a systematic decrease in animat density over time. Thus, the simulations modeled 

the animals as a closed population with a high residency factor. This approach is clearly conservative in 

terms of allowing for more prolonged exposures than would be expected from species with a lower 

residency factor. 

The AIM simulations created a realistic animal movement track for each animat and were based on 

the best available animal behavioral data. It was assumed that, collectively, the ~4,000 animat tracks 

derived for each simulation (area/species combination) were a reasonable representation of the 

movements of the animals in the population under consideration. Animat positions along each of these 

tracks were converted to polar coordinates (range and bearing) from the source to the receivers. These 

data, along with the depth of the receiver, were used to extract received level estimates from the acoustic 

propagation modeling results provided by JASCO for each source type. Specific to the modeling effort 

for this Programmatic EIS, the source levels, and therefore subsequently the received levels, include the 

embedded corrections for signal pulse length and M-weighting as discussed in Appendix D. For each 

bearing, distance, and depth from the source when it was operating at that site, the received level values 

were expressed as SPLs with units of dB re 1μ Pa. 

Each animat’s received levels were converted back to intensity and summed over the duration of the 

exercise to generate the integrated energy level. These were expressed in terms of dB re 1μPa2

-sec or 

dB SEL. These exposure metrics were evaluated with the following criteria. 

The acoustic threshold criteria, previously discussed in Section 3.0 of this appendix, were then 

applied to the results of the AIM modeling, then the number of animats that exceeded each criterion was 

determined. These values were then scaled by the ratio of model-to-real world densities and corrected for 

the number of blocks or square kilometers modeled. These scaled values were reported as the predicted 

impact of each survey type, at each location, for each applicable source. 

The output results from AIM provided the number of Level A and Level B harassment takes for each 

species, by season, modeled region, and survey type that exceed the specific threshold considered. These 

results will then be corrected to adjust for two parameters in the modeling: (1) the density of 

animats/animals in the modeled area; and (2) actual number of blocks that would be surveyed in each 

modeled region. The animal densities used in the AIM modeling are deliberately kept high to ensure that 

a statistically valid result is obtained. Typically, these “modeled” densities are at least an order of 

magnitude greater than the actual marine mammal density present in the region. Therefore, the modeling 

result is corrected or scaled by the ratio of the actual density divided by the modeled density. Similarly, 

the number of potential impacts is also scaled to derive a “per block survey” level of potential impacts. 

The predicted potential impacts can then be calculated by multiplying this value by the number of surveys 

of that type to be performed in that year, and summing the potential impacts to that species from all 

survey types combined. 

7.2. AIM MODELING OF THE SOURCE MOVEMENT

For this assessment, the creation of each modeling simulation began with the creation of a movement 

pattern for the seismic airgun source vessel representing a different survey type. The seismic airgun 

survey types modeled included 2D, 3D, WAZ, VSP, and HRG. (Note that these last two surveys use the 

small array airgun only). The parameters for each survey type are provided in Table E-9. 

The marine mineral and renewable energy programs also conduct HRG surveys, but these surveys are 

not expected to use airguns; they would use active acoustic sound sources such as boomer and chirp 

subbottom profilers, side-scan sonars, and multi-beam depth sounders. The details of how these sources 

were modeled in AIM are provided in Table E-10.
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-33 

Table E-9 

 

Seismic Airgun Source Vessel Parameters for AIM Simulations 

Survey Type 

Spacing of Horizontal 

and Vertical Lines 

(km) 

Gridded? Comments Number of 

Blocks Modeled 

Shot Interval 

(seconds) 

2D 2.0 x (NA) No 5 x 5 = 25 15 

3D 1.0 x 1.0 Yes 2 x 2 = 4 15 

Wide Azimuth 

(WAZ) 1.0 x 1.0 Yes Use multiples of 3D surveys 2 x 2 = 4 15 (per survey) 

Vertical Seismic Profile 

(VSP) 1.0 x 1.0 Yes Use 3D surveys 1 x 2 = 2 15 

High-resolution 

Geophysical (HRG) 0.08 x NA No Uses small airgun 1 x 1 = 1 variable 

The marine mineral and renewable energy programs also conduct HRG surveys, but these surveys are 

not expected to use airguns; they would use active acoustic sound sources such as boomer and chirp 

subbottom profilers, side-scan sonars, and multi-beam depth sounders. The details of how these sources 

were modeled in AIM are provided in Table E-10.

Table E-10 

 

Marine Mineral and Renewable Resource Source Vessel Parameters for AIM Simulations 

Survey Type Area Modeled 

(km) 

Spacing of Horizontal and 

Vertical Lines 

(km) 

Gridded? Comments 

Marine Mineral Exploration 1.8 x 1.8 0.03 x (NA) No Multiple electromechanical 

sources (no airguns) 

Marine Mineral Exploration 1.8 x 1.8 0.2 x (NA) No Multiple electromechanical 

sources (no airguns) 

Renewable Energy Hazard 3.5 x 3.5 0.15 x 0.15 Yes Multiple electromechanical 

sources (no airguns) 

Renewable Energy Exploration 2.1 x 2.0 0.03 x 0.15 Yes Multiple electromechanical 

sources (no airguns) 

7.3. AIM MODELING OF THE ANIMAL MOVEMENT

7.3.1. Movement 

Animals move through four dimensions: 3D space plus time. Several movement parameters are used 

in the model to produce a simulated movement pattern that accurately represents real animal movements. 

A typical dive pattern is shown below in Figure E-16. It consists of two phases; the first is a shallow 

respiratory sequence, which is followed by a deeper, longer dive. 

-70

-60

-50

-40

-30

-20

-10

0

0 5 10 15 20 25 30

Time (minutes)

Depth (meters)

Figure E-16. Typical Dive Pattern. 
E-34 Atlantic G&G Programmatic EIS

These two phases are represented in the model with the values as input into the box below in 

Figure E-17. 

Figure E-17. Parameters Used to Specify the Typical Dive Pattern Shown in Figure E-16. 

The top row has the values for the shallow, respiratory dives. In this case, the animal dives from the 

surface to a maximum depth of 5 m. The second row describes the second phase of the dive. In this 

phase the animal dives to a depth between 50 and 75 m (164 and 246 ft). In this example, the animal 

spends time at both 60 and 50 m (197 and 164 ft) before surfacing. The pattern then repeats. 

The horizontal component of the course is handled with the “heading variance” term. It allows the 

animal to turn up to a certain number of degrees at each movement step. In this case, the animal can 

change course 20 degrees on the surface, but only 10 degrees underwater. This example is for a narrowly 

constrained set of variables, appropriate for a migratory animal. 

7.3.2. Heading Variance 

There are few published data that summarize marine mammal movement in terms of heading 

variance, or the amount of course change per unit time. The default setting allows the course to deviate 

between 0 and 30 degrees per minute. 

7.3.3. Aversions 

In addition to movement patterns, the animats can be programmed to avoid certain environmental 

situations. For example, this option can be used to constrain an animal to a particular depth regime. The 

following example (Figure E-18) constrains the animal to waters between 2,000 and 5,000 m (6,562 and 

16,404 ft) deep. One modification was made for these simulations in the animal’s habitat. Normally 

deep-water species were allowed to move into waters as shallow as 100 m (328 ft). 

Figure E-18. Example Showing the Aversions to Limit an Animat to Waters between 2,000 and 5,000 m 

(6,562 and 16,404 ft). 

7.3.4. Species Behavior Parameters 

The specific animal behavioral parameters that were used in this analysis are provided below. Where 

the “Surfacing/Dive Angle” column is empty, there were no meaningful data available so, 75o was used as 

a default value. Under the “Speed Distribution” column, “Normal” indicates that the distribution of speed 

values between the limits was normally distributed. Under the “Depth Limit/Reaction Angle” column, 

the first number indicates the minimum depth limit in meters, and “reflect” indicates that if an animat 

moves to that shallow water limit, it will move away from the shallow water and back into deeper water. 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-35 

7.3.4.1. Minke Whale 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Minke 

Whale 1/3 75o 20/100 2/6 Surface 45 

Dive 20 1/18 Gamma (3.25,2) 10/reflect 

Surface Time 

A mean surface time of 1.72 minutes, with a range of 0.63-2.35 minutes was reported by (Stern, 

1992). 

Dive Depth 

Inferred from other species, however reduced in depth, since minkes are likely to be pelagic feeders, 

feeding on species found near the surface (Olsen and Holst, 2001). 

Dive Time 

The mean dive time reported by (Stern, 1992) was 4.43 (+/- 2.7) minutes. Dive times measured off 

Norway range from approximately 1-6 minutes (Joyce et al., 1989). Dive times also show small diel and 

seasonal variability (Stockin et al., 2001), but the variability is small enough to be considered not 

significant for AIM modeling. Dive times were non-normal, as indicated by the figure on the right, taken 

from (Øien et al., 1990). 

Speed 

The mean speed value for minke whales in Monterey Bay was 4.5 (+/- 3.45) knots 

(8.3 +/- 6.4 km/hr) (Stern, 1992). Satellite tagging studies have shown movement of up to 79 km/day 

(49 mi/day) (3.3 km/hr [2.1 mi/hr]). Minke whales being pursued by killer whales were able to swim at 

15-30 km/hr (Ford et al., 2005). 

A gamma function was fit to the available speed data. The modal speed of this function is 4.5 km/hr 

(2.8 mi/hr), matching the Stern (1992) data, and has a maximum of 18 km/hr (11 mi/hr), somewhat less 

than the maximum speed achievable (30 km/hr [19 mi/hr]), observed during predation. “Cruising” 

minkes have been reported at 3.25 m/s (10.66 ft/s) (Blix and Folkow, 1995). 

Habitat 

Minke whales in Monterey Bay were reported to be in a median depth of 48.6 m (159.4 ft) (Stern, 

1992). They are known to move into very shallow water as well as deep oceanic basins. The 10-m 

(33-ft) limit and reflection aversion are intended to let minkes roam freely, but to stay off the beach. 

Group Size 

Mean group size in the Antarctic was 1.6 individuals (Blix and Folkow, 1995). 

Residency 

Foraging minke whales have been shown to exhibit small scale site fidelity (Morris and Tscherter, 

2006). Therefore, foraging minke whales should have their course change parameters set to be variable to 

allow for small net movements. 
E-36 Atlantic G&G Programmatic EIS

7.3.4.2. Sei/Bryde’s Whale 

There is a paucity of data for these species. Since they are similar in size, data for both species have 

been pooled to derive parameters for these two species. 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Min/Max Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Sei/Bryde’s 

Whale 1/1 90/75o 10/40 (80) 

50/267 (20) 2/11 30/300 (50%) 90/300 (50%) 1/20 5/1 

Surface Time 

No direct data available, fin whale values used. 

Dive Depth 

A limited number of Bryde’s whales have been tagged with time-depth recorders (TDRs) (Alves et 

al., 2010). Shallow dives, less than 40 m (131 ft) were recorded 85 percent of the time, while deep dives 

occurred 15 percent of the time. The maximum dive depth reported was 267 m (876 ft). 

Two distinct dive types were noted for Bryde’s whales. Both performed a long series of shallow dives 

of less than 40 m (131 ft) until 1.5 hours before sunset. The animals then made the deepest dives. During 

the night, sequential deep dives took place. Foraging lunges were recorded during about half of these 

night time dives. 

Dive Time 

Sei whale dive times ranged between 0.75 and 11 minutes, with a mean duration of 1.5 minutes 

(Schilling et al., 1992). Most of the dives were short in duration, presumably because they were 

associated with surface or near-surface foraging. The same paper reported surface times that ranged 

between 2 s and 15 minutes. The maximum dive time reported for two Bryde’s whales was 9.4 minutes 

(Alves et al., 2010) with mean durations of 4-6 minutes. 

Heading Variance 

Observations of foraging sei whales found that they had a very high reorientation rate, frequently 

resulting in minimal net movement (Schilling et al., 1992). 

Speed 

A tagging study found an overall speed of advance for sei whales was 4.6 km/hr (2.9 mi/hr) (Brown, 

1977). The highest speed reported for a Bryde’s whale was 20 km/hr (Cummings, 1985). A Bryde’s 

whale being attacked by killer whales traveled ~9 km in 94 minutes, with most of the travel occurring in 

first 50 minutes, producing an estimated speed of 10.8 km/hr (6.7 mi/hr) (Silber et al., 1990). The 

maximum speed of sei whales reported from a satellite tracking study was 7.6 m/s (25 ft/s), although the 

distribution of speeds was highly skewed toward lower values (Olsen et al., 2009). The speed parameters 

used in AIM are 0-20 km/hr (0-12.4 mi/hr), using a gamma distribution with alpha and beta parameters of 

5 and 1. These values produce the following distribution, which covers the reported range of speed 

(Olsen et al., 2009) and approximated the mean value reported by Brown (1977). 

Habitat 

Sei whales are known to feed on shallow banks such as Stellwagen Bank (Kenney and Winn, 1986). 

Therefore, sei and Bryde’s whales are allowed to move into shallow water. 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-37 

Group Size 

Sei whales in the Gulf of Maine were seen in groups of 1-6 animals with a mean group size of 

1.8 whales (Schilling et al., 1992). Bryde’s whales in the Gulf of California were seen in groups of 

1-2 animals, with a mean size of 1.2 whales (Silber et al., 1994). 

7.3.4.3. Blue Whale 

Model Parameters 

Min/Max 

Surface 

Time (min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Blue Whale 

(non-foraging) 1/2 75o 20/100 2/18 30/300 (50%) 

90/300 (50%) 3/14 Norm. 100/reflect 

Blue Whale 

(foraging) 1/2 75o 20/100 (50) 

100/300 (50) 

2/18 

4/18 

30/300 

90/90 3/14 Norm. 100/reflect 

Surface Time 

Only one of four satellite tagged blue whales reported surface intervals of 7-90 s with a mean of 48 s. 

The other three did not report intervals >60 s, indicating that the surface time was short (Lagerquist et al., 

2000). 

Dive Depth 

Croll et al. (2001) reported a mean dive depth of 140 m (459 ft) (+/- 46.01) for non-foraging animals, 

while foraging whales had a mean dive depth of 67.6 m (221.8 ft) (+/- 51.46). Satellite tagged whales off 

California had a maximum dive depth of 192 m (630 ft) (Lagerquist et al., 2000). The distribution of dive 

depths was bimodal, as typified by the plot below (note that this is from one animal). A series of blue 

whales had crittercam’s attached to them off California and Mexico. The maximum dive depth reported 

was 293 m (961 ft) (Calambokidis et al., 2008). Many of these animals had deep feeding dives, with 

lunges occurring 200-260 m (656-853 ft). Notably, one animal transitioned from deep feeding dives of 

decreasing depth as the sun set, transitioning into shallow non-feeding dives. This indicated that there 

may be a diurnal character to some blue whale behavior. 

Separate animats for foraging and non-foraging blue whales were created. Foraging animats will 

have a 50:50 distribution between deep dives (200-300 m [656-984 ft]) and shallower dives (20-100 m 

[66-328 ft]). 

Dive Time 

Mean dive times of 4.3, 7.8, 4.9 5.7, 10, and 7 minutes have been reported for blue whales (Laurie, 

1933; Doi, 1974; Lockyer, 1976; Croll et al., 1998; Croll et al., 2001). The best estimate of the maximum 

dive time is 14.7 minutes (Croll et al., 2001), although a max time of 30 minutes was reported by (Laurie, 

1933). The longest dive reported for satellite tagged whales was 18 minutes, although the mean dive 

times for all whales was 5.8 (+/- 1.5) minutes (Lagerquist et al., 2000). 

Speed 

Dive descent rates of 1.26 m/s (4.13 ft/s) have been recorded (Williams et al., 2000). A mean surface 

speed of 1.25 m/s (4.10 ft/s) with a maximum speed of 2.0 m/s (6.6 ft/s) was reported from satellite tags 

(Mate et al., 1999), although satellite data tend to smooth the track and therefore underestimate speed. A 

second satellite tag study found straight-line speed (under) estimates from 1.3 to 14.2 km/hr (0.8 to 

8.8 mi/hr). 
E-38 Atlantic G&G Programmatic EIS

Group Size 

Blue whales in the Eastern Tropical Pacific had a modal group size of one, although pods of two were 

somewhat common (Reilly and Thayer, 1990). The mean group size of blue whales off Australia 

(B. m. brevicauda) was 1.55 (Gill, 2002). 

7.3.4.4. Fin Whale 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Fin Whale 1/1 75o 20/250 (90) 

250/470 (10) 

5/8 

1/20 20 1/16 Norm. 30/reflect 

Surface Time 

Remarkably good data for surface times exist for fin whales. A log survivorship analysis of all 

inter-blow intervals was used to determine an inflection point of 28 and 31 s between surface and dive 

activity for feeding and non-feeding animals, respectively (Kopelman and Sadove, 1995). The mean 

surface duration for fin whales without boats present off Maine was 54.63 s (standard deviation 

[SD]=59.61) while dive times were 200.84 s (SD=192.91) (Stone et al., 1992). 

Dive Depth 

Foraging fin whales had mean dive depths of 97.9 +/- 32.59 m, while traveling fin whales had mean 

dive depths of 59.3 +/- 29.67 m (Croll et al., 2001). Migrating fin whales were determined to have a 

maximal dive depth of 364 m (1,194 ft), (Charif et al., 2002). Fin whales in the Mediterranean Sea 

typically dove to ~100 m (~382 ft), occasionally dove to 470 m (1,542 ft) or more (Panigada et al., 1999), 

however these are unusually deep dives. The animats here model the more typical dive pattern 90 percent 

of the time. Foraging fin whales off California had a mean maximum dive depth of 248 m (814 ft) 

(Goldbogen et al., 2006). Based on this study, the most frequent AIM dive depth is extended to 250 m. 

Dive Time 

Foraging fin whales had mean dive times of 6.3 +/- 1.53 minutes, while traveling fin whales had 

mean dive times of 4.2 +/- 1.67 minutes (Croll et al., 2001). The maximum dive time observed was 

16.9 minutes. Fin whales off the east coast of the U.S. were observed to have mean dive times of 

2.9 minutes. Ranges for feeding animals ranged from 29 to 1,001 s, while non-feeding animals had 

longer dives between 32 and 1,212 s (Kopelman and Sadove, 1995). Panigada et al. (1999) found that 

shallow (<100 m [<328 ft]) dives had a mean dive time of 7.1 minutes, while deeper dives had dive times 

of 11.7 and 12.6 minutes. Fin whales foraging on Jeffrey’s Ledge in the Gulf of Maine had mean dive 

times of 5.83-5.89 minutes (Ramirez et al., 2006). 

Speed 

Watkins (1981) reported a mean speed of 10 km/hr (6 mi/hr) ranging from 1 to 16 km/hr (0.6 to 

10 mi/hr) with bursts of 20 km/hr (12 mi/hr) reported. Mean descent speeds of 3.2 m/s (10.5 ft/s) 

(SD=1.82) and ascent speeds of 2.1 m/s (6.9 ft/s) (SD=0.82) have been reported from fin whales in the 

Mediterranean (Panigada et al., 1999). 

Habitat 

Fin whales are found feeding on shallow banks and in bays (Woodley and Gaskin, 1996) as well as in 

the abyssal plains of the ocean (Watkins, 1981). Fin whales are allowed to move into shallow water in 

AIM, with a 30-m (98-ft) inshore limit to keep them out of the very shallow waters. 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-39 

Group Size 

Fin whales in the Gulf of Mexico had a mean group size of 5.7 with a range in group sizes from 

1 to 50 (Silber et al., 1994). In the Mediterranean Sea the mean group size over a number of years was 

1.75 animals (Panigada et al., 2005). 

7.3.4.5. North Atlantic Right Whale 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Right Whale 4/5 75o 113/130 11/13 30 3/6 Norm. 

Surface Time 

Mean surface time for right whales was less than 60 s (Winn et al., 1995). Therefore a one minute 

surface time was used for AIM. 

Dive Depth 

Right whale feeding dives in the northwest Atlantic were characterized by rapid descent to depths 

between 80 and 175 m (262 and 574 ft). The median depth was 119 m (390 ft) with a 90 percent 

confidence interval between 113 and 130 m (371 and 427 ft) (Baumgartner and Mate, 2003). This 

90 percent confidence range was used for the dive depth range. In a nearby area, right whales dove to 

depths between approximately 120 and 180 m (394 and 591 ft) (Nowacek et al., 2004). 

Dive Time 

The median dive time for foraging right whales was 12.65 minutes, with a 95 percent confidence 

interval of 11.4-12.9 minutes (Baumgartner and Mate, 2003). 

Speed 

Descent speed of diving right whales had a 95 percent confidence interval of 1.3-1.5 m/s (4.3-4.5 ft/s) 

while the ascent speed was 1.4-1.7 m/s (4.6-5.6 ft/s) (Baumgartner and Mate, 2003). Radio tagged whales 

that remained in the Bay of Fundy had a mean speed of 1.1 km/hr while those that left the bay had a mean 

speed of 3.5 km/hr (2.2 mi/hr) (Mate et al., 1997). Note that radio tagging tends to underestimate whale 

speed, since the data greatly smooth the recorded course of the animal. 

Habitat 

Northern right whales are currently found in the northwest Atlantic Ocean and the North Pacific. In 

the North Atlantic, they are found offshore eastern Canada and the U.S. northeast coast during the 

summer foraging season. They migrate along the coast and their breeding area is in the shallow waters 

offshore of Florida and Georgia. It is believed that a portion of the population migrates to an 

undiscovered location. 

Group Size 

The group size of surface active groups (SAGs) in the Bay of Fundy ranged from 2 to 15 animals 

(Parks and Tyack, 2005). 
E-40 Atlantic G&G Programmatic EIS

7.3.4.6. Humpback Whale (Feeding) 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Feeding 

Humpback 

Whale 

1/2 75o 10/60 (20) 

40/100 (75) 

100/150 (5) 

5/10 

90/300 

90/90 

90/90 

1/8 Norm. (Min = 100)/ 

reflect 

Surface Time 

Approximately 65 percent of all surfacing observed in Alaska were 2 minutes in length or less 

(Dolphin, 1987a). Surface times in Hawaii are similar with the exception of surface active groups 

(Frankel, pers. obs.). 

Dive Depth 

Humpback whale dive depths have been measured on the feeding grounds. Seventy-five percent of 

their dives were to 40 m (131 ft) or less with a maximum depth of 150 m (492 ft) (Dolphin, 1988). Dive 

depth appears to be determined by prey distribution. Whales in this study were primarily foraging upon 

euphausiids. There is also a strong correlation of dive depth and dive time and is described by the 

following equation (Dolphin, 1987a): 

Time (s) = 0.52 * depth (m) +3.95, r2

 = 0.93 

Feeding humpbacks off Kodiak Alaska had a mean maximum depth of 106.2 m (348 ft) with 

62 percent of the dives occurring between 92 and 120 m (302 and 394 ft) with a maximum of ~160 m 

(~348 ft) (Witteveen et al., 2008). The humpbacks appeared to be feeding largely on capelin and pollock. 

There are strong differences in the data between these two studies. This difference may reflect the 

distribution of prey rather than behavioral abilities of the whales. 

Dive Time 

The maximum of the continuous portion of the distribution of dive times was 15 minutes (Dolphin, 

1987a). The distribution was skewed toward shorter dives. Several dive steps can be programmed in 

AIM to capture this variability. 

Heading Variance 

Satellite tracking of feeding humpback whales in the Southern Ocean showed very erratic travel, and 

animals frequently remained in a specific area for up to a week at a time. There were periodic movements 

between feeding areas (Dalla Rosa et al., 2008). Therefore, the heading variance for feeding humpbacks 

was set relatively high, for 80 percent of the time. Twenty percent of the time the heading variance was 

set as low to simulate movement between feeding areas. 

Speed 

Mean speeds for humpbacks are near 4.5 km/hr (2.8 mi/hr). The measured range is 2-11.4 km/hr 

(1-7 mi/hr) (excluding stationary pods) (Gabriele et al., 1996). Feeding humpbacks in the Southern 

Ocean had mean measured speeds between 2.26 and 4.03 km/hr (1.4 and 2.5 mi/hr) (Dalla Rosa et al., 

2008). These values were derived from short segments of satellite tracking data; therefore, they are likely 

underestimates of speed. 

Ascent rates during dives range from 1.5 to 2.5 m/s (4.8 to 8.2 ft) while descent rates range between 

1.25 and 2 m/s (4.1 and 6.6 ft/s) (Dolphin, 1987b). The mean speed for all pod types in Glacier Bay was 

3.31 km/hr (1 mi/hr) (Baker and Herman, 1989). 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-41 

Habitat 

Migrating humpbacks swim both along the coast (California population) as well as through the 

abyssal plains. Humpbacks swim along coastal regions are known to swim further offshore than gray 

whales. Therefore, the minimum depth for this species has been set at 100 m (328 ft). 

Group Size 

Ninety-six percent of 27,252 pods in the Gulf of Maine were composed of 1-3 animals with a modal 

size of one adult (Clapham, 1993). 

7.3.4.7. Humpback Whale (Winter Grounds: Singer) 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Humpback 

Singer 1/1 75o 10/25 5/25 20 0/1 Norm. >1,000/reflect 

Surface Time 

Singers typically surface for <1 minute. Singers in the Caribbean blew between 2 and 8 times per 

surfacing (Chu, 1988). 

Dive Depth 

Humpback singers have relatively shallow depths. 

Dive Time 

Dive times typically range from 10 to 25 minutes. Observations of 20 singers in the Caribbean found 

dive times between five and 20 minutes in duration (Chu, 1988). 

Heading Variance 

The heading variance is set very low for singers. While traveling very slow to stationary, they tend to 

swim along the coast. 

Speed 

Most singers are stationary although very few move at high speeds. 

Habitat 

On the wintering grounds most singers are found within the 100 fathom contour, but a few are found 

in deeper waters. 

Group Size 

The vast majority of singers are found alone. The largest pod reported containing a singer was four 

animals (Frankel et al., 1995). 
E-42 Atlantic G&G Programmatic EIS

7.3.4.8. Humpback Whale (Migrating) 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Migrating 

Humpback 

Whale 

1/2 75o 10/40 5/10 10 2/10 Norm. (Min =100)/ 

reflect 

Dive Depth 

Humpback whale dive depths have been measured on the feeding grounds. Seventy-five percent of 

their dives were to 40 m (131 ft) or less (Dolphin, 1988). It is likely that migrating animals would also 

predominantly dive to these shallow depths. Humpbacks foraging off California had a mean maximum 

dive depth of 156 m (512 ft) (Goldbogen et al., 2008). 

Dive Time 

Surface times range between 1 and 2 minutes while dive times range between 5 and 10 minutes 

(Gabriele et al., 1996). Foraging humpbacks off California had mean dive times of 7.8 +/- 2.0 minutes 

(Goldbogen et al., 2008). 

Heading Variance 

The heading variance was set very low for migrating animals. Most non-competitive group breeding 

animals also have linear travel. Migrating humpbacks swam very close to magnetic north from Hawaii 

with very little deviation (Mate et al., 1998). 

Speed 

Mean speeds for humpbacks are near 4.5 km/hr (2.8 mi/hr). The measured range is 2-11.4 km/hr 

(1.2-7.1 mi/hr) (excluding stationary pods) (Gabriele et al., 1996). Satellite tracked migrating humpback 

whales moved at a minimum of 150 km/day (93 mi/day) (6.25 km/hr [3.9 mi/hr]) for a mother and calf 

pod, while another two whales moved 110 km/day (68 mi/day) (4.5 km/hr [2.8 mi/hr]). Humpbacks off 

Australia were estimated to migrate at a mean speed of 8 km/hr (5 mi/hr), with a range between 4.8 and 

14.2 km/hr (3 and 9 mi/hr) (Chittleborough, 1953). More recent studies of Australian humpbacks found a 

mean northern migration speed of 5.47 km/hr (3.4 mi/hr), while the southern migration speed had a mean 

of 5.02 km/hr (3.12 mi/hr) for non-calf pods, while calf pods had mean speeds of 5.03 and 4.25 km/hr 

respectively (Chaudry, 2006). 

Habitat 

Migrating humpbacks swim both along the coast (California population) as well as through the 

abyssal plains. Humpbacks swim along coastal regions are known to swim further offshore than gray 

whales. Therefore, the minimum depth for this species has been set at 100 m (328 ft). Non-calf pods 

migrating off Australian had a mean offshore distance of 3,177 m (10,423 ft) during the northern 

migration and 2,560 m (8,399 ft) during the southern migration. Calf pods migrated “significantly” closer 

inshore (Chaudry, 2006). 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-43 

7.3.4.9. Common Dolphin 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Common 

Dolphin 1/1 75o 50/200 1/5 30 2/9 Norm. 100-1,000/ 

reflect 

Dive Depth 

Dive depths are reported to be between 50 and 200 m (164 and 656 ft) (Evans, 1994). 

Dive Time 

The maximum dive time reported was five minutes (Heyning and Perrin, 1994). 

Speed 

The maximum sustainable speed for common dolphins was measured at 2.5 m/s (8.2 ft/s) (9 km/hr 

[5.6 mi/hr]) (Hui, 1987). 

Habitat 

Common dolphins off the NE United States were concentrated along the shelf edge between 100 and 

200 m (328 and 656 ft) (Selzer and Payne, 1988). In the Mediterranean common dolphins were found in 

waters between 25 and 1,300 m (82 and 4,265 ft) deep with 95 percent of the animals in water between 

247 and 326 m (810 and 1,070 ft) (Cañadas et al., 2002). 

Group Size 

Common dolphins in the Gulf of California were found in groups of 4-1,100 animals, with a mean 

size of 254.3 dolphins (Silber et al., 1994). Off the Pacific Coast of Costa Rica, the mean group size was 

220.67 (SD=220.6) (May-Collado et al., 2005). 

7.3.4.10. Blackfish: False Killer Whale, Pygmy Killer Whale, Melon-headed Whale 

Studies describing the movements and diving patterns of these animals are rare and sparse. 

Therefore, they have been combined into a single “blackfish” category. 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

False/Pygmy 

killer whales 1/1 75o 5/50 (80) 

50/100 (20) 2/12 30 2/22.4 Gamma. 200/reflect 

Surface Time 

Individual melon-headed whales spend less than one minute on the surface although the group may 

remain near the surface for long periods of time (Frankel, pers. obs.). 

Dive Depth 

The maximum dive depth of a single false killer whale off the Madeira Islands was 72 m (236 ft). 

Most of the time was spent at depths deeper than 20 m (66 ft) and the dives were V-shaped (Alves et al., 

2006). Three false killer whales in Hawaii had shallow dives as well with maximum depths of 22, 52, 
E-44 Atlantic G&G Programmatic EIS

and 53 m (72, 171, and 174 ft) (Ligon and Baird, 2001). It should be noted that these animals were 

feeding on fish. 

Dive Time 

No directly measured data were available for “blackfish” whales so data from pilot whales was used 

for dive time. 

Speed 

Maximum speed recorded for false killer whales was 28.8 km/hr (17.9 mi/hr) (Rohr et al., 2002), 

although the typical cruising speed is typically 20-24 percent less than the maximum speed (Fish and 

Rohr, 1999). This “typical” maximum of 22 km/hr (14 mi/hr) was used as the maximum speed for AIM. 

Habitat 

False killer whales off the Madeira Islands were found in water depths from 900 to 2,000 m 

(900 to 6,562 ft) (Alves et al., 2006). 

Group Size 

False killer whales in the Gulf of Mexico had group sizes between 20 and 35 (mean=27.5, standard 

error [SE]=7.5, n=2) (Mullin et al., 2004). False killer whales off Costa Rica had a mean group size of 

36.16 (+/- 52.38) (May-Collado et al., 2005). 

7.3.4.11. Shortfin and Longfin Pilot Whales 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Pilot Whales 1/1 75o 5/100 (80) 

10/1,000 (20) 

1/10 

5/21 30 2/12 Norm. 200/reflect 

Surface Time 

A rehabilitated long-finned pilot whale in the North Atlantic was equipped with a satellite tag and a 

TDR. The log survivorship plot of dive time from this animal had an inflection point at about 40 s 

(Mate et al., 2005). The authors did not feel that this qualified as a breakpoint to separate surface and 

dive behavior. However, it does suggest that most surface intervals are less than one minute. 

Dive Depth 

Long-finned pilot whales in the Mediterranean were observed to display considerable diurnal 

variation in their dive depths. During the day, they never dove to more than 16 m (52 ft). However, at 

night, they dove to maximum depths of 360 and 648 m (1,181 and 2,126 ft) with mean depth of 308 and 

416 m (1,011 and 1,365 ft) (Baird et al., 2002). Rehabilitated long-finned pilot whales dove to 312 m 

(1,024 ft) on Georges Bank which has a depth of 360 m (1,181 ft), so these values should not be taken as 

the maximum. The distribution of dive depths was also skewed toward lower values (Nawojchik et al., 

2003). 

Short-finned pilot whales off the Canary Islands had maximum depth of 1,019 m (3,343 ft) (Aguilar 

Soto et al., 2008). The majority of these were to depths of less than 100 m (328 ft) while the remainder of 

depths were approximately evenly distributed between 100 and 1,000 m (328 and 3,281 ft). 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-45 

Dive Time 

Baird et al. (2002) reported on dives of two individual long-finned pilot whales and dive times varied 

between 2.14 and 12.7 minutes during the night. During the day animals spent all of their time in the top 

16 m (52 ft). 

A rehabilitated long-finned pilot whale in the North Atlantic had dive times between 1 and 6 minutes 

(Mate et al., 2005). Other rehabilitated long-finned whales were reported to dive to at least 25 minutes 

although the distribution is skewed toward shorter dives with most lasting about two minutes (Nawojchik 

et al., 2003). Long-finned pilot whales off the Faroe Islands never dove longer than 18 minutes 

(Heide-Jørgensen et al., 2002). 

Short-finned pilot whales off the Canary Islands had maximum foraging dive times of 21 minutes 

(Aguilar Soto et al., 2008). They demonstrated a near-linear relationship between dive depth and dive 

duration. Therefore shallow dives had times ranging between 1 and 10 minutes, while deep dives were 

set to have times between 5 and 21 minutes. 

Speed 

Shane (1995) reported a minimum speed of 2 km/hr (1.24 mi/hr) and a maximum of 12 km/hr 

(7.5 mi/hr) for pilot whales. During the day in the Mediterranean, animals slowly swam, with mean 

values for two animals of 2.85 and 3.18 km/hr (1.8 and 2 mi/hr), while at night, they swam faster at 

6.83 and 5.48 km/hr (4.24 and 3.4 mi/hr) (Baird et al., 2002). A single satellite tracked long-finned pilot 

whale had a minimum speed of 1.4 km/hr (0.9 mi/hr) (Mate et al., 2005). The speed of traveling pilot 

whales (G. scammoni) was estimated at 4-5 knots (Norris and Prescott, 1961, cited in Mate et al., 2005). 

Vertical dive speeds of three TDR tagged long-finned pilot whales ranged from 0.79 to 3.38 m/s 

(2.6 to 11.1 ft/s) with a mean of 1.99 m/s (6.5 ft/s) (Heide-Jørgensen et al., 2002). 

Habitat 

The minimum water depth for pilot whales in the Gulf of Mexico was 246 m (807 ft) (Davis et al., 

1998), while off of Spain, they preferred water deeper than 600 m (1,969 ft) (Cañadas et al., 2002). 

Group Size 

Short-finned pilot whales in the Gulf of Mexico ranged in group size between 5 and 50 (mean=20.4, 

SE=3.6, n=11) (Mullin et al., 2004). Off the Pacific Coast of Costa Rica the mean group size of pilot 

whales was 14.22 individuals (SD=12.06) (May-Collado et al., 2005). 

7.3.4.12. Risso’s Dolphin 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Risso's 

Dolphin 1/3 75o 150/1,000 2/12 30 2/12 Norm. 150/reflect 

Dive Depth 

Dive depths of 150-1,000 m (492-3,281 ft) were inferred from the Risso’s squid-eating habits and 

from similar species. 

Dive Time 

No data on dive times could be found. The values for blackfish were used which have a similar 

ecological niche. 
E-46 Atlantic G&G Programmatic EIS

Speed 

Risso’s dolphins off Santa Catalina Island were reported to have speeds ranging between 2 and 

12 km/hr (1.24 and 7.5 mi/hr) (Shane, 1995). 

Habitat 

Risso’s dolphins were seen in water deeper than 150 m (492 ft) in the Gulf of Mexico, most often 

observed between 300 and 750 m (984 and 2,461 ft) (Davis et al., 1998). Off Chile they were seen in 

waters deeper than 1,000 m (3,281 ft) (Olavarria et al., 2001) and off Spain, they were found deeper than 

600 m (1,969 ft) (Cañadas et al., 2002). In all cases this association seems to be driven by the local 

oceanographic upwelling conditions that increase primary productivity. 

Group Size 

In the Pacific group sizes were measured between 1 and 220 animals with a geometric mean of 10.7. 

An estimated 76.4 percent of the groups contained fewer than 20 animals (Leatherwood et al., 1980). 

Group sizes in the Gulf of Mexico ranged between 2 and 78 animals with a mean of 12.7 (SE=2.0, n=39) 

(Mullin et al., 2004). The mean group size off the Pacific Coast of Costa Rica was 11.57 (SD=9.64) 

(May-Collado et al., 2005). 

7.3.4.13. Large Beaked Whales 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Berardius 1/7 75o 800/1,453 (90)

50/200 (10) 

48/68 

12/70 

30/300 (50) 

90/300 (50) 3/6 Norm. 253/reflect 

Surface Time 

Surface times in Arnoux’s beaked whales ranged from 1.2 to 6.8 minutes (Hobson and Martin, 1996). 

Sowerby’s beaked whales had surface times of 1-2 minutes during which they would blow 6-8 times 

(Hooker and Baird, 1999a). 

Dive Depth 

The minimum and maximum dive depth measured for a beaked whale was 120 and 1,453 m (394 and 

4,767 ft) respectively (Hooker and Baird, 1999b). Ziphius tagged off the Canary Islands had foraging 

dives between 824 and 1,267 m (2,703 and 4,157 ft) while Blainsville’s beaked whales dove to depths 

between 655 and 975 m (2,149 and 3,199 ft) (Johnson et al., 2004). 

Northern Bottlenose whales performed shallow dives with a range of 41-332 m (135-1,089 ft) (n=33), 

while deep dives ranged from 493 to 1,453 m (1,617 to 4,767 ft) (n=23). Dive depth and dive duration 

were strongly correlated (Hooker and Baird, 1999b). 

Blainsville’s beaked whales in Hawaii performed dives to mid-water depth (100-600 m 

[328-1,969 ft]) approximately six times more frequently than at night. Dives deeper than 800 m (2,625 ft 

had no diurnal difference (Baird et al., 2008). 

Dive Time 

The minimum and maximum dive time measured was 16 and 70.5 minutes, respectively (Hooker and 

Baird, 1999b). Sowerby’s beaked whales had dives between 12 and (at least) 28 minutes in the Gully in 

Canada (Hooker and Baird, 1999a). Arnoux’s beaked whale had modal dive times between 

35-65 minutes (mean=46.4 min, SD=13.1), with a maximum dive time of at least 70 minutes (Hobson and 

Martin, 1996). Tagging results with Cuvier’s beaked whale had one animal diving for 50 minutes 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-47 

(Johnson et al., 2004). Mesoplodon stejnegeri were observed to dive for “10-15 minutes” in Alaska 

(Loughlin, 1982). 

Blainsville’s beaked whales and Cuvier’s beaked whales both regularly dived for 48-68 minutes on 

deep dives (>800 m [>2,625 ft]). 

Heading Variance 

Sowerby’s beaked whales surfacing in the Gully were reported to have no apparent orientation, and 

would change orientation up to 180° between surfacing (Hooker and Baird, 1999a). 

Speed 

Dive rates averaged 1 m/s (3.3 ft/s) or 3.6 km/hr (2.2 mi/hr) (Hooker and Baird, 1999b). A mean 

surface speed of 5 km/hr (3 mi/hr) was reported by (Kastelein and Gerrits, 1991). 

Habitat 

The minimum sea depth in which beaked whales were found in the Gulf of Mexico was 253 m 

(830 ft) (Davis et al., 1998). In the Gully in Canada, Sowerby’s beaked whales were found in water 

ranging from 550 to 1,500 m (1,804 to 4,921 ft) in depth (Hooker and Baird, 1999a). Blainsville’s beaked 

whales (M. densirostris) were found in water depths of 136-1,319 m (446-4,327 ft) in the Bahamas, and 

were found most often in areas with a high bathymetric slope (MacLeod and Zuur, 2005). Mesoplodons

were found in waters from 700 to >1,800 m (2,297 to >5,906 ft) off Scotland and the Faroe Islands (Weir, 

2000) and between 680 and 1,933 m (2,231 and 6,342 ft) in the Gulf of Mexico (Davis et al., 1998). 

Baird et al. (2006) reported that Blainsville’s beaked whales off Hawaii were found in waters from 

633 to 2,050 m (2,077 to 9,726 ft) deep (mean=1,119) while Cuvier’s beaked whales were found in 

waters from 1,381 to 3,655 m (4,531 to 11,992 ft) deep (mean=2,131). 

Group Size 

Mesoplodon stejnegeri in Alaska had pod sizes between 5 and 15 animals (Loughlin, 1982). 

Sowerby’s beaked whale in the Gully in Canada had group sizes between 3 and 10 (Hooker and Baird, 

1999a). Dense-beaked whales off the Canary Islands had group sizes ranging between 2 and 9 with a 

mean size of 3.44 whales (Ritter and Brederlau, 1999). Sightings of Longman’s beaked whale in the 

western Indian Ocean found group sizes between 1 and 40 with a mean size of 7.2 whales (Anderson et 

al., 2006). 

7.3.4.14. Dwarf and Pygmy Sperm Whales (Kogia spp.) 

The data on dwarf and pygmy sperm whales are rare. Data for these two similar species have been 

combined. 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Kogia spp. 1/2 75o 200/1,000 5/12 30 1/11 Norm. 117/reflect 

Surface Time 

Observations of Kogia off Hawaii found that they remained at the surface for up to a “few” minutes 

then dove (Baird, 2005). 
E-48 Atlantic G&G Programmatic EIS

Dive Depth 

Kogia were found in the Gulf of Mexico in waters less than 1,000 m (3,281 ft) along the upper 

continental slope (Baumgartner et al., 2001). The dive limits of 200-1,000 m (656-3,281 ft) were chosen 

based on similar species diving deeply to feed and within the physical constraints of the environment. It 

should be noted that Kogia have been seen in waters almost 2,000 m (6,562 ft) deep (Davis et al., 1998) 

but they may not be diving to the bottom. 

Dive Time 

Maximum dive time reported for Kogia is 12 minutes (Hohn et al., 1995). A rehabilitated pygmy 

sperm whale made long dives from 2 to 11 minutes in length at night and shorter dives during the day 

(Scott et al., 2001). 

Speed 

Tracking of a rehabilitated pygmy sperm whale found that speeds range from 0 to 6 knots (11 km/hr 

[7 mi/hr]) with a mean value of 3 knots (Scott et al., 2001). 

Habitat 

Kogia were found in the Gulf of Mexico at a minimum depth of 176 m (577 ft) (Davis et al., 1998). 

They were found off Hawaii in waters between 450 and 3,200 m (1,476 and 10,499 ft) deep, with a mean 

of 1,425 m (4,675 ft) (Baird, 2005). Kogia in the Philippines were found in waters from 117 to 3,744 m 

(384 to 12,284 ft) in depth (Dolar and Perrin, 2003). 

Group Size 

Group sizes off Hawaii ranged between 1 and 6 animals (Baird, 2005) and group sizes in the Gulf of 

Mexico range between 1 and 3 (Mullin et al., 2004). 

7.3.4.15. Lagenorhynchus Species 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Lags 1/1 75o 25/125 1/3 30 2/9 Norm. 

Surface Time 

Surface times for tagged white-sided dolphins were less than one minute (Mate et al., 1994). 

Dive Depth 

No direct data on dive depth are available for any of the Lagenorhynchus. However, in the Atlantic 

they feed on herring and in the Pacific they feed on squid and mesopelagic fishes. For Atlantic 

white-sided dolphin a maximum dive depth of 125 m (410 ft) is used since this covers the depth range of 

herring; it is slightly shallower than the other dolphin species due to the Lagenorhynchus’ short dive time. 

Dive Time 

Maximum dive time for a tagged white-sided dolphin was 4 minutes, although the mean time was 

<1 minute (Mate et al., 1994). Peale’s dolphin (L. australis) dove from 1 to 130 s (de Haro and Iniguez, 

1997). 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-49 

Speed 

The mean minimum speed of 5.7 km/hr (3.5 mi/hr) was estimated by the straight line distance 

between satellite tag locations, which is almost certainly an underestimate of real-world swimming speeds 

(Mate et al., 1994). The maximum “minimum speed” was 14.22 km/hr (8.83 mi/hr). A white-sided 

dolphin in captivity swam between 1.5 and 3.5 m/s (5 and 11.5 ft/s) (5.4 and 12.6 km/hr [3.4 and 

7.8 mi/hr) (Curren et al., 1994). Theodolite tracking of dusky dolphins (L. obscurus) produced mean 

speeds between 3.68 and 6.08 km/hr (2.4 and 3.8 mi/hr) with 10th and 90th percentiles of ~2 and ~9 km/hr 

(~ 1 and ~ 6 mi/hr) (Yin, 1999). 

Group Size 

The mean size of Atlantic white-sided dolphin groups was 52 (Weinrich et al., 2001). The mean 

group size of Pacific white-sided dolphins was 30.8 (Barlow, 1995). In Southeast Alaska, the group size 

was extremely variable, ranging from 1 to 500 animals, with an overall mean of 35.6 animals (Dahlheim 

and Towell, 1994). 

7.3.4.16. Fraser’s Dolphin 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Fraser’s 

Dolphin 1/1 75o 10/700 1/6 30 2/9 Norm. 100/reflect 

Dive Depth 

Fraser’s dolphins dive to about 600-700 m (1,969-2,297 ft) to feed which is much deeper than spinner 

dolphins (Dolar et al., 2003). Numerous records indicated that the primary prey of Fraser’s dolphins is 

found at great depth (Caldwell et al., 1976; Miyazaki and Wada, 1978; Robison and Craddock, 1983), 

although there has been at least one report of near-surface feeding (Watkins et al., 1994). All other 

behavioral parameters are taken from Stenella species since there are no direct data for Fraser’s dolphin. 

The dive time has been increased to six minutes to account for the deeper dives. 

Group Size 

A single group of Fraser’s dolphins was seen off the Pacific Coast of Costa Rica and had a group size 

of 158 (May-Collado et al., 2005). 

7.3.4.17. Small Beaked Whales (Mesoplodon, Ziphius, Tasmacetus) 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Beaked 

Whales 1/7 75o 1,000/1,453 (60)

100/800 (40) 

48/68 

12/30 

30/300 (50) 

90/300 (50) 3/6 Norm. 253/reflect 

Surface Time 

Surface times in Arnoux’s beaked whales ranged from 1.2 to 6.8 minutes (Hobson and Martin, 1996). 

Sowerby’s beaked whales had surface times of 1-2 minutes, during which they would blow 6-8 times 

(Hooker and Baird, 1999a). 
E-50 Atlantic G&G Programmatic EIS

Dive Depth 

The minimum and maximum dive depth measured for a beaked whale was 120 and 1,453 m (394 and 

4,767 ft) respectively (Hooker and Baird, 1999b). Cuvier’s beaked whales tagged off the Canary Islands 

had foraging dives between 824 and 1,267 m (2,703 and 4,157 ft) while Blainsville’s beaked whales dove 

to depths between 655 and 975 m (2,149 and 3,199 ft) (Johnson et al., 2004). 

Northern Bottlenose whales performed shallow dives with a range of 41-332 m (135-1,089 ft) (n=33), 

while deep dives ranged from 493 to 1,453 m (1,617 to 4,767 ft) (n=23). Dive depth and dive duration 

were strongly correlated (Hooker and Baird, 1999b). 

Blainsville’s beaked whales in Hawaii performed dives to mid-water depth (100-600 m 

[328-1,969 ft]) approximately six times more frequently than at night. Dives deeper than 800 m (2,625 ft) 

had no diurnal difference (Baird et al., 2008). 

Dive Time 

The minimum and maximum dive time measured was 16 and 70.5 minutes respectively (Hooker and 

Baird, 1999b). Sowerby’s beaked whales had dives between 12 and (at least) 28 minutes in the Gully in 

Canada (Hooker and Baird, 1999a). Arnoux’s beaked whale had modal dive times between 

35-65 minutes (mean=46.4 min, SD=13.1) with a maximum dive time of at least 70 minutes (Hobson and 

Martin, 1996). Tagging results with Ziphius had one animal diving for 50 minutes (Johnson et al., 2004). 

Mesoplodon stejnegeri were observed to dive for 10-15 minutes in Alaska (Loughlin, 1982). 

Blainsville’s beaked whales and Cuvier’s beaked whales both regularly dove for 48-68 minutes on 

deep dives (>800 m [>2,625 ft]). 

Heading Variance 

Sowerby’s beaked whales surfacing in the Gully were reported to have no apparent orientation, and 

would change orientation up to 180° between surfacing (Hooker and Baird, 1999a). 

Speed 

Dive rates averaged 1 m/s (3.3 ft) or 3.6 km/hr (2.2 mi/hr) (Hooker and Baird, 1999b). A mean 

surface speed of 5 km/hr (3.1 mi/hr) was reported by Kastelein and Gerrits (1991). 

Habitat 

The minimum sea depth in which beaked whales were found in the Gulf of Mexico was 253 m 

(830 ft) (Davis et al., 1998). Sowerby’s beaked whales in the Gully in Canada were found in water 

ranging from 550 to 1,500 m (1,804 to 4,921 ft) in depth (Hooker and Baird, 1999a). Blainsville’s beaked 

whales (M. densirostris) were found in water depths of 136-1,319 m (446-4,327 ft) in the Bahamas, and 

were found most often in areas with a high bathymetric slope (MacLeod and Zuur, 2005). Mesoplodons

were found in waters from 700 to >1,800 m (2,297 to 5,906 ft) off Scotland and the Faroe Islands (Weir, 

2000) and between 680 and 1,933 m (2,231 and 6,342 ft) in the Gulf of Mexico (Davis et al., 1998). 

Baird et al. (2006) reported that Blainsville’s beaked whales off Hawaii were found in waters from 

633 to 2,050 m (2,077 to 6,726 ft) deep (mean=1,119 m [3,671 ft]) while Cuvier’s beaked whales were 

found in waters from 1,381 to 3,655 m (4,531 to 11,992 ft) deep (mean=2,131 m [6,991 ft]). 

Group Size 

Mesoplodon stejnegeri in Alaska had pod sizes between 5 and 15 animals (Loughlin, 1982). 

Sowerby’s beaked whale in the Gully in Canada had group sizes between 3 and 10 (Hooker and Baird, 

1999a). Dense-beaked whales off the Canary Islands had group sizes ranging between 2 and 9 with a 

mean size of 3.44 whales (Ritter and Brederlau, 1999). Sightings of Longman’s beaked whale in the 

western Indian Ocean found group sizes between 1 and 40, with a mean size of 7.2 whales (Anderson et 

al., 2006). 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-51 

7.3.4.18. Killer Whale 

There is a remarkable paucity of quantitative data available for killer whales considering their coastal 

habitat and popular appeal. Nevertheless, most data from “blackfish” were used to model orca with the 

exception of dive depth. The different feeding ecology of these species makes very deep dives apparently 

unnecessary. When additional data allow, separate animats need to be developed for “resident” and 

“transient” killer whales. 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Killer Whale 1/1 75o 10/180 1/10 30 3/12 Norm. 25/reflect 

Dive Depth 

Killer whales feeding on herring were observed to dive to 180 m (591 ft) (Nøttestad et al., 2002). 

Killer whales are found in at least two “races”, transients and residents. Transients feed primarily on 

marine mammals whereas residents feed primarily on fish. Residents were reported to dive to the bottom 

(173 m [568 ft]) (Baird, 1994). Baird (1994) also reported that while residents dive deeper than 

transients, the transients spent a far greater amount of time in deeper water. Individual resident killer 

whales in the Pacific northwest had maximum dive depths ranging between 24 and 264 m (79 and 866 ft) 

with a group mean maximum depth of 140.8 m (462 ft) (SD=61.8, n=34) (Baird et al., 1995). The 

distribution of dive depths reported by Baird et al. (2005) was strongly skewed toward shallow values. 

Dive Time 

The daytime dive times for males were 2.79 minutes, significantly longer than the 2.09 minute dive 

times for females (Baird et al., 2005). 

Speed 

Uncalibrated swim speed data were presented by Baird et al. (2005). Killer whales chasing minke 

whales had prolonged speeds of 15-30 km/hr (9-19 mi/hr) (Ford et al., 2005) although these speeds are 

probably obtained only during predation. A shore-based study of southern resident killer whales in 

Washington State had a mean speed of 9.5 km/hr (5.9 mi/hr) with a mean range of 4.7-16.1 km/hr 

(2.9-10 mi/hr) (Kriete, 2002). The mean speed of control animals was approximately 5.3 km/hr 

(3.3 mi/hr), measured during a study of the response of killer whales to vessels (Williams et al., 2002). A 

similar study reported a mean speed of 6.64 km/hr (4.13 mi/hr) without vessels and 6.478 km/hr 

(4.03 mi/hr) in the presence of vessels (Bain et al., 2006). Taken together, these three studies produced a 

speed range of 3-12 km/hr (1.9-7.5 mi/hr) for use in AIM. 

Habitat 

Killer whales are known to occur in very shallow water (e.g., rubbing beaches) as well as cross open 

ocean basins. However, they are usually coastal and most often found in temperate waters. 

Killer whales in the Gulf of California were seen in groups of 2-15 whales with a mean of 8.5 and a 

SD of 9.19 (n=2) (Silber et al., 1994). Off the Pacific Coast of Costa Rica, the mean group size was 

3.51 (SD=2.99, n=7) (May-Collado et al., 2005). 
E-52 Atlantic G&G Programmatic EIS

7.3.4.19. Harbor Porpoise 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Harbor 

Porpoise 1/1 17/31 

1/10 (35) 

10/40 (45) 

40/100 (15) 

100/230 (5) 

1/4 30 2/7 Norm. 100-1,000/ 

reflect 

Surface Time 

Mean surface time was reported as 3.9 s (Otani, 2000). 

Dive Depth 

Maximum observed dive depth for a free-ranging harbor porpoise was 64.7 m (212 ft) (Otani, 2000). 

However, the same study reported that >90 percent of dives were less than 10 m (33 ft). Another TDR 

study with seven animals tagged had dive depths that ranged from a mean of 14 +/- 16 m (46 +/- 52 ft) to 

41 +/- 32 m (135 +/- 105 ft) while the mean for all animals tagged was 25 +/- 30 m (82 +/- 98 ft) 

(Westgate et al., 1995). One large female made a very deep dive to 226 m (741 ft) although dives this 

deep were infrequent. 

Dive Time 

Maximum observed dive time for a free-ranging harbor porpoise was 193 s (Otani, 2000) although 

most dives were less than one minute in length. The mean dive duration of seven animals in the Bay of 

Fundy was 65 +/-33 s (Westgate et al., 1995). 

Speed 

Mean descent speed was 2.9 km/hr (1.8 mi/hr) with a maximum descent speed of 15.5 km/hr 

(9.6 mi/hr). Ascent speeds were similar, with a mean of 3.24 km/hr (2 mi/hr) and a maximum of 

14.5 km/hr (9 mi/hr) (Otani, 2000). TDR tagged animals moved at least 51 km (32 mi) in a 24 hr period 

(2.125 km/hr [1.3 mi/hr]) (Westgate et al., 1995). A captive harbor porpoise swam between 3.6-7.2 km/hr 

(2.2-4.5 mi/hr) (Curren et al., 1994). A speed range of 2-7 km/hr (1.2-4.3 mi/hr) was used in AIM to 

represent the harbor porpoise speed. 

Group Size 

The mean group size of harbor porpoise off California was 5.0 individuals (n=31) (Barlow, 1995). 

7.3.4.20. Sperm Whale 

There are indications of diurnal differences in diving behavior (Aoki et al., 2007). There is also 

evidence of large-scale variability between environments. Therefore, these parameters should be 

considered generalized and warrant location specific refinement. 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-53 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time 

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Sperm Whale 8/11 90/75o 600/1,400 (90)

200/600 (10) 18/65 20 1/10 Norm. 200/reflect 

Atlantic Ocean Model Parameters 

Atlantic 

Sperm Whale 5/9 90/75o 600/1,000 35/65 30/300 (50) 90/300 (50) 1/8 Norm. 200/reflect 

Surface Time 

Male sperm whales in New Zealand had a mean duration on the surface of 9.1 minutes, with a range 

of 2-19 minutes (Jaquet et al., 2000). The distribution of surface times was non-normal, with 68 percent 

of the surface times falling in between 8 and 11 minutes. These values were used for AIM modeling. 

Surfacing and Dive Angles 

Surfacing angles of 90° and diving angles between 60° and 90° have been reported (Miller et al., 

2004). 

Dive Depth 

The maximum, accurately measured, sperm whale dive depth was 1,330 m (4,364 ft) (Watkins et al., 

2002). Foraging dives typically begin at depths of 300 m (984 ft) (Papastavrou et al., 1989). Digital 

acoustic recording tag (DTAG) data from the Gulf of Mexico show that most foraging dives were 

between the depths of 400-800 m (1,312-2,625 ft), with occasional dives between 900 and 1,000 m 

(2,953 and 3,281 ft) (Jochens et al., 2008, Figure 5.2.2). 

Sperm whale diving is not uniform. As an example, data from a paper on sperm whale diving 

reported different dive types (Amano and Yoshioka, 2003). The AIM can now accommodate these 

different dive types at different frequencies of use. 

 Depth Time 

Type of Dive N AIM min AIM max AIM min AIM max 

Dives w/ active bottom period 65 606 1082 33.17 41.63 

Dives w/o active bottom period 4 417 567 31.29 33.71 

V shaped dives 3 213 353 12.77 20.83 

Total 72 

Dive depths have also been shown to have diel variation in some areas while others do not show this 

variation (Aoki et al., 2007). These differences have been attributed to the behavior of the prey species. 

Tagged whales off California changed their dive patterns in response to changes in the depth of tagged 

squid (Davis et al., 2007). 

Male sperm whales foraging in high latitude waters dove to a maximum depth of 1,860 m (6,102 ft), 

but the median dive depth was only 175 m (574 ft) (Teloni et al., 2008). 

In the Atlantic, maximum dive depths ranged from 639 to 934 m (2,096 to 3,064 ft) (Palka and 

Johnson, 2007). 
E-54 Atlantic G&G Programmatic EIS

Average Duration (min) 

Area Foraging Dive 

Total Descent Ascent 

Inter-Dive 

Interval Surface Interval 

North Atlantic 44.6 24.4 20.2 7.1 70.0 

Gulf of Mexico 44.7 22.2 22.4 8.2 63.7 

Mediterranean 40.3 24.4 19.3 9.7 57.5 

Average Depth (m) 

Area 

Maximum Depth of Foraging Dives Inter-Dive 

Interval Surface Interval 

North Atlantic 933.9 1.15 5.6 

Gulf of Mexico 638.7 0.45 4.6 

Mediterranean 797.3 0.34 4.9 

Sperm whales showed diel variability off Ogasawara, Japan. Whales dove deeper during the day 

(mean=853 +/- 130 m [2,799 +/- 427 ft]) than at night (mean=469 +/- 122 m [1,539 +/- 400 ft]) (Aoki et 

al., 2007). However, off the Kumano Coast, there was not a large difference in depths (561 versus 646 m 

[1,841 versus 2,119 ft]). 

Dive Time 

Sperm whale dive times average 44.4 minutes in duration and range from 18.2 to 65.3 minutes 

(Watkins et al., 2002). In the Gulf of Mexico, the modal dive time is about 55 minutes (Jochens et al., 

2008, Figure 4.4.3). Dive times in the Atlantic averaged 40-45 minutes (Palka and Johnson, 2007). 

Dive times off Ogasawara, Japan had an average of 40.1 minutes (SD=4.5) during the day and a mean 

of 32.3 minutes (SD=5.3) at night (Aoki et al., 2007). Off the Kumano Coast of Japan, they had 

intermediate values of 36.1 minutes (SD=3.7) during the day and 34.1 (SD=7) minutes at night. 

Heading Variance 

Whales in the Gulf of Mexico tend to follow bathymetric contours (Jochens et al., 2008). Relative 

angles between direction of movements and direction of contours have been calculated and transformed 

so that 0 shows alignment with the orientation of the contour, -90 would be moving directly offshore, and 

+90 would indicate a movement directly inshore (Jochens et al., 2008, Figure 4.4.5). 

Speed 

Sperm whales are typically slow or motionless on the surface. Mean surface speeds of 1.25 km/hr 

(0.78 mi/hr) were reported by Jaquet et al. (2000) and 3.42 km/hr (2.13 mi/hr) (Whitehead et al., 1989). 

Their mean dive rate ranges from 5.22 to 10.08 km/hr (3.24 to 6.26 mi/hr) with a mean of 7.32 km/hr 

(4.55 mi/hr) (Lockyer, 1997). In Norway, horizontal swimming speeds varied between 0.72 and 

9.36 km/hr (0.45 and 5.8 mi/hr) (Wahlberg, 2002). Sperm whales in the Atlantic Ocean swam at speeds 

between 2.6 and 3.5 km/hr (1.6 and 2.2 mi/hr) (Jaquet and Whitehead, 1999; Watkins et al., 1999). Mean 

speeds in the Gulf of Mexico were 3.3 km/hr (2.1 mi/hr) (Jochens et al., 2008). Based on these data, a 

minimum speed of 1 km/hr (0.6 mi/hr) and a maximum speed of 8 km/hr (5 mi/hr) was set for sperm 

whales specified with a normal distribution so that mean speeds would be about 4 km/hr (2.5 mi/hr). 

Off Ogasawara Japan, sperm whales swam faster during the day (mean=2.0 m/s [6.6 ft/s], SD=0.3) 

than during the night (mean=1.5 m/s [5 ft/s], SD=0.3). 

Habitat 

Sperm whales are found almost everywhere, but they are usually in water deeper than 480 m 

(1,575 ft) (Davis et al., 1998). However, there have been sightings of animals in shallow water (40-100 m 

[131-328 ft]) (Whitehead et al., 1992; Scott and Sadove, 1997). In the Gulf of California there was no 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-55 

relationship between depth or bathymetric slope and abundance and animals were seen in water as 

shallow as 100 m (328 ft) (Jaquet and Gendron, 2002). Based on these reports, a compromise value of 

200 m (656 ft) was used as the shallow water limit for sperm whales. 

Group Size 

Social, female-centered groups of sperm whales in the Pacific have “typical” group sizes of 

25-30 animals, based on the more precise measurements in (Coakes and Whitehead, 2004), although less 

precise estimates are as high as 53 whales in a group. 

7.3.4.21. Stenella: Spinner, Spotted and Striped Dolphins 

Most Stenella species have strong diurnal variation in their behavior. Separate daytime and nighttime 

animats was built for this species by programming two dive behaviors. The relative proportion of these 

dive types can be scaled by the local photoperiod with the AIM weighting parameter. 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Stenella 1/1 75o Day: 5/25 (50) 

Night: 10/400 (10) 

Night: 10/100 (40)

1/4 30 2/9 Norm. 10/reflect 

Dive Depth 

Spinner dolphins feed during the night and rest inshore during the daytime. At night they dive to 

about 400 m (1,312 ft) to feed (Dolar et al., 2003). 

Pantropical spotted dolphins off Hawaii also dive deeper at night than during the day. The daytime 

depth had a mean of 12.8 m (42 ft), with a maximum of 122 m (400 ft), whereas the night-time mean was 

57 m (187 ft), with a maximum of 213 m (699 ft) (Baird et al., 2001). 

Spinner dolphins off Hawaii typically track and forage upon the mesopelagic boundary layer as it 

migrates both vertically and horizontally at night. It appears that dolphins have to dive deeply only at the 

very beginning and end of the migration (Benoit-Bird and Au, 2003) foraging mostly at moderate depths. 

Therefore, 10 percent of the dives were set to be deep, 40 percent of the dives were “typical” foraging 

depths, with a maximum of 150 m (492 ft), and 50 percent of the dives were set to represent the daytime 

resting behavior ranging between 5 and 25 m (16 and 82 ft). 

Dive Time 

A single spotted dolphin has dive times ranging between 1 and 204 s (Leatherwood and Ljungblad, 

1979). Pantropical spotted dolphins off Hawaii had a mean dive duration of 1.95 minutes (SD=0.92) 

(Baird et al., 2001). An Atlantic spotted dolphin tagged with a satellite linked TDR had a maximum dive 

time of 3.5 minutes (Davis et al., 1996). A four minute dive time maximum was used for modeling 

purposes in AIM. 

Speed 

The mean speed of striped dolphins in the Mediterranean was estimated at 6.1 knots (11 km/hr 

[6.8 mi/hr]) and burst to 32 knots were observed (Archer and Perrin, 1999). A maximum speed of 

20 km/hr (12 mi/hr) was chosen as a typical (non-burst) maximum speed. A tagged spotted dolphin was 

tracked at estimated average speeds of 2.3-10.7 knots with bursts exceeding 12 knots (Leatherwood and 

Ljungblad, 1979). The estimated burst speed of spotted dolphins in the Eastern Tropical Pacific was 

21.6 km/hr (13.4 mi/hr) for adults and 10.8 km/hr (6.7 mi/hr) for neonates. The estimated long-term top 

speed is 9 km/hr (5.6 mi/hr) for adults and 3.6 km/hr (2.2 mi/hr) for neonates (Edwards, 2006). The 
E-56 Atlantic G&G Programmatic EIS

Edwards (2006) paper also summarized speed estimates and duration for a number of species. Therefore 

their estimate of 9 km/hr (5.6 mi/h) was used for long-term movements, as modeled in AIM. 

Habitat 

In the Gulf of Mexico spinner dolphins were seen in water deeper than 526 m (1,726 ft), striped 

dolphins were seen in water deeper than 570 m (1,870 ft), and spotted dolphins were seen in water deeper 

than 102 m (335 ft) (Davis et al., 1998). Spinner dolphins in Hawaii are known to move into shallow 

bays during the day (Norris and Dohl, 1980). 

Group Size 

Group size estimates were summarized, and the majority of striped dolphin groups were less than 

500 animals. The mean of the smaller groups was 101 animals (Archer and Perrin, 1999). Spotted 

dolphins off Costa Rica had group sizes between 1 and 50 (mean=10.16, SD=9.61) (May-Collado and 

Ramirez, 2005). 

Summary of Gulf of Mexico Data (Source: Mullin et al., 2004) 

Species Min Group Size Max Group Size Mean SE N 

Pantropical spotted dolphin 5 210 49.0 4.5 47 

Atlantic spotted dolphin 5 48 22.4 3.9 12 

Striped dolphin 7 150 46.3 16.0 8 

Spinner dolphin 48 200 91.3 36.4 4 

Clymene dolphin 9 168 59 19.5 7 

Clymene dolphins off Costa Rica had a mean group size of 76.1 (SE=11, n=109) (Fertl et al., 2003). 

Summary of Pacific Costa Rica Data (May-Collado et al., 2005) 

Species Mean SD 

Pantropical spotted dolphin 29.38 58.28 

Striped dolphin 48.9 43.05 

Spinner dolphin 100.59 107.7 

7.3.4.22. Bottlenose Dolphin 

In many environments, there can be coastal and pelagic stocks of bottlenose dolphins. This is 

certainly the case off the east coast of the U.S., however defining the range of offshore form is difficult 

(Wells et al., 1999). Regardless of the genetic differences that may exist between these two forms, they 

frequently occur at different densities and are split into two animat categories. 

Model Parameters 

Min/Max 

Surface Time 

(min) 

Surface/Dive 

Angle 

Dive Depth (m) 

Min/Max 

(Percentage) 

Min/Max 

Dive Time

(min) 

Heading Variance 

(angle/time) 

Min/Max 

Speed 

(km/hr) 

Speed 

Distribution 

(α,β) 

Depth 

Limit/Reaction 

Angle 

Bottlenose 

(Coastal) 1/1 75o 15/98 1/3 30 2/16 Norm. 10/reflect 

Bottlenose 

(Pelagic) 1/1 75o

6/50 (80) 

50/100 (5) 

100/250 (5) 

250/450 (10) 

1/2 

2/3 

3/4 

5/6 

30/300 (45) 

90/90 (45) 

90/90 (10) 

2/16 Norm. 101/1,226 

reflect 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-57 

Dive Depth 

An early maximum recorded dive depth for wild bottlenose dolphins is 200 m (656 ft) (Kooyman and 

Andersen, 1969). More recently, offshore bottlenose dolphins were reported to dive to depths greater 

than 450 m (1,476 ft) (Klatsky et al., 2007). 

A satellite tagged dolphin in Tampa Bay, Florida had a maximum dive depth of 98 m (322 ft) 

(Mate et al., 1995). This value was used as the maximum dive depth for the coastal form of bottlenose. 

Dive Time 

Measured surface times ranged from 38 s to 1.2 minutes (Lockyer and Morris, 1986, 1987; Mate et 

al., 1995). Dive depths for a juvenile bottlenose had a mean value of 55.3 s although the distribution was 

skewed toward shorter dives (Lockyer and Morris, 1987). However, pelagic bottlenose dolphins were 

observed to dive for periods longer than five minutes (Klatsky et al., 2007). 

Speed 

Bottlenose dolphins were observed to swim for extended periods at speeds of 4-20 km/hr 

(2.5-12.4 mi/hr), although they could burst (for about 20 s) at up to 54 km/hr (34 mi/hr) (Lockyer and 

Morris, 1987). Dolphins in the Sado Estuary, Portugal had a mean speed of 4.3 km/hr (2.7 mi/hr) and 

maximum speed of 11.2 km/hr (7 mi/hr) (Harzen, 2002). A more recent analysis found that maximum 

speed of wild dolphins was 20.5 km/hr (12.7 mi/hr), although trained animals could double this speed 

when preparing to leap (Rohr et al., 2002). Maximum speeds of wild dolphins in France was 4.8 m/s 

(15.7 ft/s), with an average speed (relative to water) of 7.9 km/hr (4.9 mi/hr) (Ridoux et al., 1997). 

Bottlenose dolphins off Argentina swam much faster (14 km/hr [9.7 mi/hr]) when in water >10 m (>33 ft) 

than while in shallow water (5.8 km/hr [3.6 mi/hr]) (Würsig and Würsig, 1979). 

Habitat 

In the Gulf of Mexico, bottlenose dolphins where observed in water depths between 101 and 1,226 m 

(331 and 4,022 ft) (Davis et al., 1998). However tagged animals have been observed to swim into water 

5,000 m (16,404 ft) deep (Wells et al., 1999). 

Group Size 

Bottlenose dolphins in the Gulf of California were seen in groups of 1-60 dolphins with a mean group 

size of 10.1 (Silber et al., 1994). In the Gulf of Mexico they were seen in groups of 1-68 individuals 

(mean=14.5, SE=1.5, n=83) (Mullin et al., 2004). Off the Pacific Coast of Costa Rica the mean group 

size was 21.5 (SD=33.73, n=176) (May-Collado et al., 2005). 

7.4. ESTIMATIONS OF SOURCE LEVEL OF EFFORT

The final information needed to calculate the overall impact from the proposed action and the 

alternatives is the number and timing of the various surveys to be performed. The two major components 

of the estimates of the survey Level of Effort (LOE) are: (1) the annual estimations of the total number of 

each survey type to be conducted; and (2) the spatial distribution of these surveys in the 35 modeling 

regions (regions 1-21 for seismic airgun surveys for oil and gas exploration, plus regions 22-35 for 

renewable energy and marine minerals HRG surveys). A brief discussion of these components follows. 

There are several assumptions embedded in the modeling which are necessary because this analysis is 

being performed far in advance of the actual surveys efforts. These embedded assumptions include: 

 the estimation that surveys would have an even temporal distribution throughout the 

year. This allows all seasons to be examined in the analysis and enables to analysts 

to observe particularly time periods which could cause higher impacts than others. 

The reality of Western Atlantic Ocean operations is that winter operations could 
E-58 Atlantic G&G Programmatic EIS

possibly encounter the worst conditions in general, aside from operations during a 

hurricane; 

 the marine mammal densities are averaged for each area and this value is used in the 

analysis. This is reasonable because the exact location of each survey is unknown 

and on average, much or most of these regions would eventually be surveyed; 

 nominal values used to describe the survey geometries are subject to change and most 

likely would be based on previous surveys conducted and their results; and 

 nominal source levels and configurations were modeled. 

7.4.1. Annual Survey Levels of Effort (LOE) 

The BOEM has provided the annual LOE for each of the survey types out to the year 2020. The 

tables showing these LOE are included in the Programmatic EIS (Chapter 3), and a condensed version is 

presented in Table E-11. 

Table E-11 

 

Projected Levels of Seismic Airgun Surveys for Oil and Gas Exploration 

in the Mid- and South Atlantic Planning Areas, 2012-2020 

Mid-Atlantic Planning Area South Atlantic Planning Area 

Year 

2D 

(km) 

3D 

(blocks)a

WAZ 

(blocks)b

HRG 

(line km) 

VSP 

(line km) 

2D 

(km) 

3D 

(blocks)a

WAZ 

(blocks)b

HRG 

(line km) 

VSP 

(line km) 

2012 0 0 0 0 0 0 0 0 0 0 

2013 83,400 0 0 0 0 28,450 0 0 0 0 

2014 160,950 0 0 0 0 56,900 0 0 0 0 

2015 12,875 0 0 0 0 8,050 0 0 0 0 

2016 64,375 400 0 0 0 48,300 300 0 0 0 

2017 41,800 200 0 0 0 38,624 200 0 3,220 0 

2018 16,100 200 100 3,220 0 32,200 200 100 32,200 0 

2019 16,100 200 100 16,100 160 8,050 200 200 16,100 320 

2020 800 300 200 64,375 320 800 300 200 40,250 480 

TOTAL 396,400 1,300 400 83,695 480 221,374 1,200 500 91,770 800 

Abbreviations: 2D = two-dimensional; 3D = three-dimensional; HRG = high-resolution geophysical; VSP = vertical seismic 

profile; WAZ = wide azimuth. a

 3D surveys include ocean bottom cable and nodal surveys, vertical cable surveys, and 4D (time-lapse) surveys. Typically, one 

OCS block is 9 mi2

 (23.3 km2, 2,331 ha or 5,760 ac). b

 WAZ estimates include coil shooting (exclusive to WesternGeco). 

7.4.2. Spatial Distribution of the 2D Survey Effort 

The BOEM also provided the nine G&G survey applications from geophysical companies wishing to 

conduct seismic 2D surveys for oil and gas exploration in the AOI. Included in these applications were 

the descriptions of the areas to be surveyed and the planned survey geometries. 

An analysis using geographic information system (GIS) programming was conducted on these 

applications and the resulting graphic was a density plot of the entire survey effort for the Mid- and South 

Atlantic Planning Areas (Figure E-19). In the analysis, this plot was handled in a manner similar to that 

used to determine the average marine mammal densities in each modeled region. Essentially, the number 

of survey miles for each modeled region was summed and then converted into the number of standard 

blocks in each region that would be surveyed. The description included in each of the nine applications 

changed the overall geometry employed to conduct the 2D survey. This necessitated an analysis of the 

variation in these surveys, and a nominal or average 2D survey for these applications had a linear miles 

per standard block surveyed conversion of 1.54 nmi per block (2.85 km/block). This average value is less 

than that typically used in the Gulf of Mexico for 2D surveys (e.g., approximately 6.24 nmi/block), but it 

conforms to the applications and it was used in all subsequent 2D survey calculations. Similarly, an 

average 2D HRG survey conversion of 200 nmi/block (370.40 km/block) is used for this analysis. This 

value is a compromise between the 70 nmi/block value typically used in the Gulf of Mexico and the 

360 nmi/block calculated by BOEM from the applications. By using these conversion factors and the 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-59 

Figure E-19. Level of Effort Density Plot for Future 2D Seismic Airgun Surveys Based on Overlay of 

Seismic Survey Applications Submitted to BOEM. Areas with darker shading would be 

expected to have higher levels of survey effort due to overlapping survey areas. 
E-60 Atlantic G&G Programmatic EIS

applications, the spatial distribution of the various seismic airgun surveys throughout the 21 modeling 

regions was estimated. For the non-airgun HRG surveys the conversion factor used was 666.3 nmi per 

block (1234.0 km/block). 

The final adjustment to each regions 2D survey effort was to distribute temporally as per the 

distribution discussed in Section 7.4.1. The result is a distribution of the entire 2D survey effort over the 

years and modeling regions addressed in this Programmatic EIS. 

Finally, the same spatial distribution of the 2D surveys over the 21 modeling regions was also used to 

distribute the 3D, WAZ, HRG, and VSP surveys, since it follows that the 2D surveys would essentially 

act as the gateway to the follow-up surveys by showing where they would be most productive. 

7.4.3. Temporal Correction to Level of Effort (LOE) Tables to Account for Area 

Closures 

The Proposed Action includes a suite of existing regulations as well as mitigation measures that were 

developed specifically for this Programmatic EIS (Chapter 2.1.2). Specifically, all survey activity which 

was planned to occur in North Atlantic right whale critical habitat or the Southeast U.S. Seasonal 

Management Area was assumed to be rescheduled for a period other than the November 1 to April 30 

period when those areas are established. In order to incorporate this prohibition into the modeling the 

following steps were followed: 

 all surveys which would have occurred in these closure areas and occur in modeled 

areas 4 and 5 (winter), 9 and 10 (2 months of spring) and 20 and 21 (the last month of 

fall) where rescheduled to the open and available time periods at the same sites for 

periods when the North Atlantic right whales are absent; 

 since these closure areas constitute a large portion of some modeling regions 

(in some cases up to roughly 50 percent), each of the species densities were examined 

to ensure that the density being used was correct or at least conservative; and 

 the LOE for these cancelled surveys was then evenly distributed over the remaining 

months when these surveys could be performed. This was reflected in the final LOE 

tables, Tables E-12 through E-15 for 2D, 3D, WAZ, and VSP surveys respectively. 

The LOE tables for HRG surveys of oil and gas sites using the 90 cubic airgun are 

shown in Table E-16. The LOE estimates for non-airgun HRG surveys for marine 

minerals and renewable energy sites are shown in Tables E-17 and E-18, 

respectively. 

Similarly, the number of potential impacts also is scaled to derive a “per block survey” level of 

potential impacts. The predicted potential impacts can then be calculated by multiplying this value by the 

number of surveys of that type to be performed in that year, and summing the potential impacts to that 

species from all survey types combined. 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-61 

Table E-12 

 

Adjusted Level of Effort in Blocks for 2D Seismic Airgun Surveys 

 Years 

Modeled 

Area 2012 2013 2014 2015 2016 2017 2018 2019 2020 

1 0.0 1795.4 3465.8 278.9 1398.2 911.3 539.1 347.8 17.5 

2 0.0 4461.0 8626.8 721.2 3677.6 2452.6 1098.7 883.9 47.5 

3 0.0 2398.8 4738.9 571.1 3297.3 2539.6 1929.0 603.5 51.9 

4 0.0 166.5 333.0 47.1 282.6 226.0 188.4 47.1 4.7 

5 0.0 571.2 1118.8 118.2 656.7 285.9 329.1 131.2 9.8 

6 0.0 2233.8 4310.9 344.8 1724.2 1119.6 431.2 431.2 21.4 

7 0.0 4110.7 7949.8 665.4 3394.9 2256.6 1018.6 815.1 43.9 

8 0.0 1802.5 3569.4 444.7 2590.1 2012.3 1563.5 464.4 41.3 

9 0.0 842.1 1665.4 204.0 1182.8 914.9 702.8 214.3 18.7 

10 0.0 253.8 489.9 39.2 195.9 127.2 49.0 49.0 2.4 

11 0.0 1181.1 2279.3 182.3 011.7 592.0 228.0 228.0 11.3 

12 0.0 4826.6 9321.0 756.8 3809.7 2496.9 1017.0 939.9 48.0 

13 0.0 2509.1 4947.9 580.9 3330.4 2546.8 1897.5 619.7 52.0 

14 0.0 1618.1 3201.2 393.6 2284.7 1769.0 1362.5 412.9 36.2 

15 0.0 963.0 1858.5 148.7 743.4 482.7 185.9 185.9 9.2 

16 0.0 1294.3 2497.9 199.8 999.1 648.7 249.9 249.9 12.4 

17 0.0 1134.8 2191.8 178.6 900.7 591.7 244.2 221.5 11.4 

18 0.0 2733.2 5305.3 477.8 2512.1 1742.1 935.6 566.7 34.3 

19 0.0 2592.8 5106.4 588.5 3356.9 2553.4 1875.0 632.2 52.0 

20 0.0 497.0 974.2 104.3 582.3 432.8 297.3 115.2 8.7 

21 0.0 1231.0 2403.6 290.7 1675.0 1287.4 972.5 308.0 26.3 

Table E-13 

 

Adjusted Level of Effort in Blocks for 3D Seismic Airgun Surveys 

 Years 

Modeled 

Area 2012 2013 2014 2015 2016 2017 2018 2019 2020 

1 0.0 0.0 0.0 0.0 24.8 12.5 12.5 12.5 18.7 

2 0.0 0.0 0.0 0.0 65.2 33.9 33.9 33.9 50.8 

3 0.0 0.0 0.0 0.0 58.4 37.0 37.0 37.0 55.6 

4 0.0 0.0 0.0 0.0 5.0 3.3 3.3 3.3 5.0 

5 0.0 0.0 0.0 0.0 11.6 7.0 7.0 7.0 10.5 

6 0.0 0.0 0.0 0.0 30.6 15.3 15.3 15.3 22.9 

7 0.0 0.0 0.0 0.0 60.2 31.3 31.3 31.3 46.9 

8 0.0 0.0 0.0 0.0 45.9 29.4 29.4 29.4 44.1 

9 0.0 0.0 0.0 0.0 21.0 13.4 13.4 13.4 20.0 

10 0.0 0.0 0.0 0.0 3.5 1.7 1.7 1.7 2.6 

11 0.0 0.0 0.0 0.0 16.2 8.1 8.1 8.1 12.1 

12 0.0 0.0 0.0 0.0 67.5 34.2 34.2 34.2 51.3 

13 0.0 0.0 0.0 0.0 59.0 37.0 37.0 37.0 55.6 

14 0.0 0.0 0.0 0.0 40.5 25.8 25.8 25.8 38.8 

15 0.0 0.0 0.0 0.0 13.2 6.6 6.6 6.6 9.9 

16 0.0 0.0 0.0 0.0 17.7 8.9 8.9 8.9 13.3 

17 0.0 0.0 0.0 0.0 16.0 8.1 8.1 8.1 12.2 

18 0.0 0.0 0.0 0.0 44.5 24.4 24.4 24.4 36.7 

19 0.0 0.0 0.0 0.0 59.5 37.1 37.1 37.1 55.6 

20 0.0 0.0 0.0 0.0 10.3 6.2 6.2 6.2 9.3 

21 0.0 0.0 0.0 0.0 29.7 18.8 18.8 18.8 28.1 
E-62 Atlantic G&G Programmatic EIS

Table E-14 

 

Adjusted Level of Effort in Blocks for WAZ Seismic Airgun Surveys 

 Years 

Modeled 

Area 2012 2013 2014 2015 2016 2017 2018 2019 2020 

1 0.0 0.0 0.0 0.0 0.0 0.0 6.2 6.4 12.5 

2 0.0 0.0 0.0 0.0 0.0 0.0 16.9 19.5 33.9 

3 0.0 0.0 0.0 0.0 0.0 0.0 18.5 34.2 37.0 

4 0.0 0.0 0.0 0.0 0.0 0.0 1.7 3.3 3.3 

5 0.0 0.0 0.0 0.0 0.0 0.0 3.5 5.8 7.0 

6 0.0 0.0 0.0 0.0 0.0 0.0 7.6 7.6 15.3 

7 0.0 0.0 0.0 0.0 0.0 0.0 15.6 18.0 31.3 

8 0.0 0.0 0.0 0.0 0.0 0.0 14.7 27.7 29.4 

9 0.0 0.0 0.0 0.0 0.0 0.0 6.7 12.5 13.4 

10 0.0 0.0 0.0 0.0 0.0 0.0 0.9 0.9 1.7 

11 0.0 0.0 0.0 0.0 0.0 0.0 4.0 4.0 8.1 

12 0.0 0.0 0.0 0.0 0.0 0.0 17.1 18.0 34.2 

13 0.0 0.0 0.0 0.0 0.0 0.0 18.5 33.6 37.0 

14 0.0 0.0 0.0 0.0 0.0 0.0 12.9 24.1 25.8 

15 0.0 0.0 0.0 0.0 0.0 0.0 3.3 3.3 6.6 

16 0.0 0.0 0.0 0.0 0.0 0.0 4.4 4.4 8.9 

17 0.0 0.0 0.0 0.0 0.0 0.0 4.1 4.3 8.1 

18 0.0 0.0 0.0 0.0 0.0 0.0 12.2 16.6 24.4 

19 0.0 0.0 0.0 0.0 0.0 0.0 18.5 33.2 37.1 

20 0.0 0.0 0.0 0.0 0.0 0.0 3.1 5.3 6.2 

21 0.0 0.0 0.0 0.0 0.0 0.0 9.4 17.2 18.8 

Table E-15 

 

Adjusted Level of Effort in Blocks for VSP Seismic Airgun Surveys 

 Years 

Modeled 

Area 2012 2013 2014 2015 2016 2017 2018 2019 2020 

1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 

2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.5 

3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.5 0.8 

4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 

5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 

6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 

7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.5 

8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.6 

9 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.3 

10 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 

11 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 

12 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.5 

13 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.5 0.8 

14 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.5 

15 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 

16 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 

17 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 

18 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.4 

19 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.5 0.7 

20 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 

21 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.4 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-63 

Table E-16 

 

Adjusted Level of Effort in Blocks for 90 Cubic Inch Airgun HRG Surveys for Oil and Gas Sites 

 Years 

Modeled 

Area 2012 2013 2014 2015 2016 2017 2018 2019 2020 

1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 

2 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.5 

3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.5 0.8 

4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 

5 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 

6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.2 

7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.5 

8 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.4 0.6 

9 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.3 

10 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 

11 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 

12 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.5 

13 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.5 0.8 

14 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.3 0.5 

15 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 

16 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 

17 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 

18 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.4 

19 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.5 0.7 

20 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1 

21 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.4 

Table E-17 

 

Adjusted Level of Effort in Blocks for Non-Airgun HRG Surveys for Marine Minerals Sites 

 Years 

Modeled 

Area 2012 2013 2014 2015 2016 2017 2018 2019 2020 

22 0.004 0.004 0.030 0.030 0.030 0.015 0.015 0.015 0.015 

23 0.083 0.083 0.355 0.355 0.355 0.243 0.243 0.243 0.243 

24 0.087 0.087 0.340 0.340 0.340 0.135 0.135 0.135 0.135 

25 0.000 0.000 0.046 0.046 0.046 0.123 0.123 0.123 0.123 

26 0.087 0.087 0.386 0.386 0.386 0.258 0.258 0.258 0.258 

27 0.083 0.083 0.279 0.279 0.279 0.016 0.016 0.016 0.016 

28 0.004 0.004 0.107 0.107 0.107 0.241 0.241 0.241 0.241 

29 0.004 0.004 0.030 0.030 0.030 0.015 0.015 0.015 0.015 

30 0.083 0.083 0.355 0.355 0.355 0.243 0.243 0.243 0.243 

31 0.087 0.087 0.340 0.340 0.340 0.135 0.135 0.135 0.135 

32 0.000 0.000 0.046 0.046 0.046 0.123 0.123 0.123 0.123 

33 0.087 0.087 0.386 0.386 0.386 0.258 0.258 0.258 0.258 

34 0.083 0.083 0.279 0.279 0.279 0.016 0.016 0.016 0.016 

35 0.004 0.004 0.107 0.107 0.107 0.241 0.241 0.241 0.241 
E-64 Atlantic G&G Programmatic EIS

Table E-18 

 

Adjusted Level of Effort in Blocks for Non-Airgun HRG Surveys for Renewable Energy Sites 

 Years 

Modeled 

Area 2012 2013 2014 2015 2016 2017 2018 2019 2020 

22 0.000 2.000 2.000 2.000 2.000 2.000 2.000 0.000 0.000 

23 6.708 7.208 7.208 7.208 7.208 7.208 0.500 0.000 0.000 

24 4.833 7.333 7.333 7.333 7.333 7.333 2.500 0.000 0.000 

25 1.875 1.875 1.875 1.875 1.875 1.875 0.000 0.000 0.000 

26 6.708 9.208 9.208 9.208 9.208 9.208 2.500 0.000 0.000 

27 4.208 4.208 4.208 4.208 4.208 4.208 0.000 0.000 0.000 

28 2.500 5.000 5.000 5.000 5.000 5.000 2.500 0.000 0.000 

29 0.000 2.000 2.000 2.000 2.000 2.000 2.000 0.000 0.000 

30 6.708 7.208 7.208 7.208 7.208 7.208 0.500 0.000 0.000 

31 4.833 7.333 7.333 7.333 7.333 7.333 2.500 0.000 0.000 

32 1.875 1.875 1.875 1.875 1.875 1.875 0.000 0.000 0.000 

33 6.708 9.208 9.208 9.208 9.208 9.208 2.500 0.000 0.000 

34 4.208 4.208 4.208 4.208 4.208 4.208 0.000 0.000 0.000 

35 2.500 5.000 5.000 5.000 5.000 5.000 2.500 0.000 0.000 

7.5. AIM RESULTS AND ADJUSTMENTS

7.5.1. Modeling Results 

The output results from AIM provide the number of Level A and Level B harassment takes for each 

species, by season, modeled region, and survey type that exceeded the specific threshold considered. 

Following the AIM runs, typically the resulting “ping-histories” or the individual received level values (in 

pressure or SPL units) for each of the modeled animats are available to be examined and summed into 

energy (SEL) units as needed. For this analysis, the TL modeling provided to the AIM model included 

both SPL and SEL values, so the received levels in the correct units are readily available without 

additional calculations. The individual animat’s SEL ping histories are then examined and summed for 

each animat to determine its total received energy, which is what is required to be compared to the 

threshold criteria. Note that nowhere in these calculations are any mitigation (e.g., ramp-ups or stopping 

transmissions) assumed or applied to the calculation. Finally, these results were then corrected to adjust 

for two parameters which were programmed into the modeling: (1) the density of animats/animals in the 

modeled area; and (2) the actual number of blocks that the model examined in each modeled region. As 

discussed previously, the animal densities used in the AIM modeling were deliberately kept high to 

ensure that a statistically valid result was obtained. Typically, these “modeled” densities are at least an 

order of magnitude greater than the actual marine mammal density present in the region. Therefore, the 

modeling result is corrected or scaled by the ratio of the actual density divided by the modeled density. 

The result of applying these two corrections to the AIM modeling is a set of three tables for each type of 

survey. Tables E-19 through E-21 are a representative example of these tables for the 2D seismic airgun 

surveys. Each of these three tables captures the seasonal and spatial variability of the results in the 21 

columns representing the 21 modeling regions, while providing the estimated impacts or takes for a 

specific threshold. The three tables, therefore, each represent one of the thresholds of interest. They are: 

(1) potential Level A impacts (takes) based on the Southall et al. (2007) criteria for one block of 2D 

survey effort; (2) potential Level A impacts (takes) based on the historic 180 dB (SPL) criterion for one 

block of 2D survey effort; and (3) the potential Level B impacts (takes) based on the historic 160 dB 

(SPL) criterion for one block of 2D survey effort. 
Table E-19 Potential Level A Takes (number of individuals) for One Block of 2D Seismic Airgun Survey Effort, Based on the Southall et al (2007) Injury Criteria Modeled Sites Common Name 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common minke whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Sei whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Bryde’s whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Blue whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Fin whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 North Atlantic right whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Humpback whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked common dolphin 0.000 0.026 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Pygmy killer whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Short-finned pilot whale 0.003 0.000 0.000 0.000 0.000 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001 Long-finned pilot whale 0.001 0.000 0.008 0.000 0.000 0.000 0.000 0.009 0.000 0.000 0.000 0.000 0.005 0.000 0.000 0.000 0.000 Risso’s dolphin 0.000 0.000 0.036 0.000 0.000 0.000 0.000 0.044 0.000 0.000 0.000 0.000 0.044 0.000 0.000 0.000 0.000 Northern bottlenose whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Pygmy sperm whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Dwarf sperm whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Atlantic white-sided dolphin 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Fraser's dolphin 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Sowerby’s beaked whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Blainville’s beaked whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.000 Gervais’ beaked whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.000 True’s beaked whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.000 Killer whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Melon-headed whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor porpoise 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Sperm whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 False killer whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Pantropical spotted dolphin 0.000 0.000 0.000 0.009 0.000 0.000 0.009 0.000 0.009 0.000 0.000 0.009 0.000 0.000 0.009 0.000 0.009 Clymene dolphin 0.000 0.000 0.000 0.004 0.000 0.000 0.004 0.000 0.004 0.000 0.000 0.004 0.000 0.000 0.004 0.000 0.004 Striped dolphin 0.000 0.000 0.000 0.011 0.000 0.000 0.084 0.000 0.011 0.000 0.000 0.022 0.000 0.000 0.020 0.000 0.011 Atlantic spotted dolphin 0.000 0.000 0.000 0.117 0.000 0.000 0.063 0.000 0.081 0.000 0.000 0.075 0.000 0.000 0.009 0.000 0.001 Spinner dolphin: 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Rough-toothed dolphin 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Bottlenose dolphin 0.000 0.000 0.000 0.000 0.026 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Cuvier’s beaked whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.008 0.000 

ORDER SIRENIA West Indian manatee 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORDER CARNIVORA Suborder Pinnipedia Hooded seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Gray seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 
Table E-20 Potential Level A Takes (number of individuals) for One Block of 2D Seismic Airgun Survey Effort, Based on the Historic NMFS Criterion (180 dB) Modeled Sites Common Name 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common minke whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Sei whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Bryde’s whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Blue whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Fin whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 North Atlantic right whale 0.000 0.000 0.000 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Humpback whale 0.000 0.000 0.001 0.000 0.001 0.000 0.000 0.001 0.001 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked common dolphin 0.012 0.019 0.245 0.036 0.142 0.011 0.016 0.243 0.300 0.049 0.008 0.012 0.250 0.215 0.010 0.033 0.010 Pygmy killer whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Short-finned pilot whale 0.002 0.037 0.247 0.003 0.001 0.001 0.020 0.244 0.033 0.002 0.000 0.017 0.150 0.034 0.019 0.005 0.001 Long-finned pilot whale 0.001 0.009 0.022 0.000 0.000 0.000 0.006 0.024 0.007 0.001 0.000 0.005 0.015 0.004 0.007 0.001 0.000 Risso’s dolphin 0.010 0.017 0.103 0.014 0.049 0.001 0.019 0.126 0.025 0.000 0.000 0.033 0.127 0.035 0.000 0.035 0.000 Northern bottlenose whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Pygmy sperm whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Dwarf sperm whale 0.000 0.000 0.001 0.000 0.000 0.000 0.000 0.001 0.000 0.000 0.000 0.000 0.001 0.001 0.000 0.000 0.000 Atlantic white-sided dolphin 0.000 0.000 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Fraser's dolphin 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Sowerby’s beaked whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Blainville’s beaked whale 0.000 0.001 0.003 0.000 0.000 0.000 0.001 0.002 0.000 0.000 0.000 0.001 0.001 0.000 0.001 0.001 0.000 Gervais’ beaked whale 0.000 0.001 0.003 0.000 0.000 0.000 0.001 0.002 0.000 0.000 0.000 0.001 0.001 0.000 0.001 0.001 0.000 True’s beaked whale 0.000 0.001 0.003 0.000 0.000 0.000 0.001 0.002 0.000 0.000 0.000 0.001 0.001 0.000 0.001 0.001 0.000 Killer whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Melon-headed whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor porpoise 0.000 0.000 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Sperm whale 0.000 0.005 0.014 0.000 0.000 0.000 0.006 0.007 0.000 0.000 0.000 0.007 0.007 0.000 0.003 0.007 0.000 False killer whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Pantropical spotted dolphin 0.005 0.007 0.021 0.020 0.015 0.004 0.006 0.021 0.022 0.021 0.004 0.005 0.022 0.026 0.006 0.006 0.006 Clymene dolphin 0.002 0.003 0.010 0.009 0.007 0.002 0.003 0.010 0.011 0.010 0.002 0.002 0.010 0.008 0.003 0.003 0.003 Striped dolphin 0.006 0.072 0.221 0.024 0.022 0.005 0.052 0.025 0.027 0.025 0.004 0.012 0.203 0.026 0.013 0.075 0.008 Atlantic spotted dolphin 0.000 0.064 0.179 0.260 0.211 0.000 0.039 0.082 0.203 0.232 0.000 0.040 0.191 0.252 0.006 0.070 0.001 Spinner dolphin: 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Rough-toothed dolphin 0.000 0.000 0.000 0.001 0.001 0.000 0.000 0.000 0.001 0.001 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Bottlenose dolphin 0.005 0.017 0.350 0.353 0.049 0.005 0.083 0.356 0.035 0.033 0.004 0.074 0.464 0.274 0.010 0.107 0.007 Cuvier’s beaked whale 0.000 0.010 0.019 0.000 0.000 0.000 0.007 0.017 0.000 0.000 0.000 0.006 0.008 0.000 0.007 0.009 0.000 ORDER SIRENIA West Indian manatee 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORDER CARNIVORA Suborder Pinnipedia Hooded seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Gray seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 
Table E-21 Potential Level B Takes (number of individuals) for One Block of 2D Seismic Airgun Survey Effort, Based on the Historic NMFS Criterion (160 dB) Modeled Sites Common Name 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common minke whale 0.001 0.001 0.000 0.000 0.003 0.001 0.001 0.000 0.000 0.004 0.001 0.001 0.000 0.004 0.000 0.000 0.000 

Sei whale 0.002 0.003 0.010 0.009 0.007 0.002 0.002 0.010 0.010 0.010 0.002 0.001 0.010 0.007 0.003 0.003 0.002 Bryde’s whale 0.002 0.003 0.009 0.010 0.007 0.002 0.002 0.009 0.010 0.010 0.002 0.001 0.010 0.008 0.003 0.003 0.003 Blue whale 0.003 0.004 0.009 0.010 0.008 0.003 0.003 0.009 0.010 0.010 0.002 0.003 0.010 0.008 0.003 0.003 0.003 Fin whale 0.004 0.004 0.040 0.011 0.010 0.003 0.004 0.008 0.051 0.009 0.003 0.003 0.040 0.010 0.003 0.020 0.004 North Atlantic right whale 0.000 0.000 0.000 0.142 0.039 0.000 0.000 0.003 0.016 0.014 0.000 0.000 0.000 0.000 0.000 0.001 0.000 Humpback whale 0.015 0.024 0.058 0.033 0.059 0.012 0.016 0.059 0.052 0.088 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked common dolphin 1.182 1.882 24.008 3.566 13.956 1.050 1.568 23.791 29.431 4.814 0.810 1.138 24.514 21.043 0.941 3.216 1.028 

Pygmy killer whale 0.003 0.005 0.010 0.009 0.010 0.003 0.003 0.010 0.010 0.012 0.002 0.003 0.009 0.008 0.002 0.004 0.003 Short-finned pilot whale 0.240 3.668 24.254 0.324 0.125 0.062 1.962 23.899 3.197 0.156 0.025 1.666 14.658 3.365 1.875 0.482 0.076 Long-finned pilot whale 0.080 0.917 2.144 0.000 0.029 0.021 0.611 2.384 0.677 0.052 0.008 0.519 1.467 0.406 0.716 0.129 0.024 Risso’s dolphin 0.968 1.678 10.082 1.398 4.778 0.061 1.856 12.365 2.456 0.043 0.023 3.203 12.472 3.470 0.047 3.421 0.028 Northern bottlenose whale 0.000 0.000 0.001 0.001 0.000 0.000 0.000 0.001 0.000 0.000 0.000 0.000 0.001 0.001 0.000 0.000 0.000 Pygmy sperm whale 0.008 0.010 0.000 0.000 0.014 0.008 0.011 0.000 0.000 0.015 0.008 0.010 0.000 0.000 0.000 0.000 0.000 Dwarf sperm whale 0.025 0.030 0.061 0.025 0.042 0.025 0.034 0.061 0.017 0.045 0.023 0.029 0.061 0.049 0.027 0.027 0.020 Atlantic white-sided dolphin 0.035 0.000 0.062 0.000 0.000 0.008 0.000 0.020 0.006 0.000 0.007 0.000 0.020 0.019 0.018 0.018 0.013 Fraser's dolphin 0.003 0.000 0.000 0.000 0.000 0.003 0.000 0.000 0.000 0.000 0.002 0.000 0.000 0.000 0.000 0.000 0.000 Sowerby’s beaked whale 0.000 0.000 0.001 0.001 0.001 0.000 0.000 0.001 0.001 0.001 0.000 0.000 0.001 0.000 0.000 0.000 0.000 Blainville’s beaked whale 0.001 0.138 0.260 0.000 0.001 0.001 0.100 0.231 0.000 0.001 0.001 0.084 0.115 0.001 0.097 0.124 0.000 Gervais’ beaked whale 0.001 0.138 0.260 0.000 0.001 0.001 0.100 0.231 0.000 0.001 0.001 0.084 0.115 0.001 0.097 0.124 0.000 True’s beaked whale 0.001 0.138 0.260 0.000 0.001 0.001 0.100 0.231 0.000 0.001 0.001 0.084 0.115 0.001 0.097 0.124 0.000 Killer whale 0.003 0.004 0.008 0.003 0.008 0.003 0.003 0.008 0.003 0.011 0.002 0.003 0.008 0.005 0.005 0.004 0.004 Melon-headed whale 0.003 0.005 0.012 0.012 0.010 0.003 0.003 0.012 0.012 0.012 0.002 0.003 0.011 0.010 0.004 0.004 0.003 Harbor porpoise 0.022 0.021 0.073 0.000 0.016 0.009 0.010 0.040 0.009 0.053 0.002 0.002 0.008 0.007 0.018 0.024 0.016 Sperm whale 0.008 0.502 1.384 0.003 0.005 0.006 0.553 0.708 0.002 0.005 0.005 0.696 0.696 0.003 0.340 0.700 0.008 False killer whale 0.003 0.005 0.016 0.018 0.010 0.003 0.003 0.016 0.004 0.012 0.002 0.003 0.016 0.006 0.004 0.005 0.003 Pantropical spotted dolphin 0.498 0.676 2.083 1.940 1.451 0.383 0.543 2.038 2.198 2.011 0.347 0.472 2.118 2.528 0.587 0.614 0.632 Clymene dolphin 0.238 0.323 0.995 0.927 0.693 0.183 0.259 0.974 1.050 0.961 0.166 0.225 1.012 0.829 0.281 0.293 0.302 Striped dolphin 0.603 7.028 21.640 2.346 2.164 0.463 5.105 2.464 2.658 2.432 0.420 1.170 19.917 2.589 1.307 7.335 0.764 Atlantic spotted dolphin 0.047 6.291 17.501 25.444 20.654 0.036 3.830 8.064 19.944 22.762 0.033 3.964 18.751 24.709 0.583 6.814 0.060 Spinner dolphin: 0.002 0.003 0.009 0.009 0.007 0.002 0.002 0.009 0.010 0.009 0.002 0.002 0.010 0.008 0.003 0.003 0.003 Rough-toothed dolphin 0.021 0.029 0.049 0.054 0.067 0.021 0.026 0.049 0.086 0.056 0.019 0.024 0.047 0.037 0.022 0.026 0.027 Bottlenose dolphin 0.501 1.684 34.290 34.629 4.811 0.473 8.098 34.882 3.385 3.267 0.394 7.267 45.474 26.882 0.982 10.488 0.680 Cuvier’s beaked whale 0.005 0.965 1.818 0.002 0.004 0.005 0.698 1.620 0.002 0.004 0.005 0.588 0.804 0.004 0.677 0.868 0.003 

ORDER SIRENIA West Indian manatee 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORDER CARNIVORA Suborder Pinnipedia Hooded seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Gray seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 
E-68 Atlantic G&G Programmatic EIS

Similar tables were produced for each of the seismic airgun surveys and non-airgun HRG surveys to 

be conducted including: 

Seismic airgun surveys 

 2D seismic surveys; 

 3D seismic surveys; 

 WAZ seismic surveys; 

 VSP seismic surveys; and 

 HRG surveys (90 in3

 airgun). 

Non-airgun HRG surveys 

 Boomer HRG marine mineral surveys; 

 Boomer HRG renewable energy surveys; 

 Side-scan sonar HRG marine mineral surveys; 

 Side-scan sonar HRG renewable energy surveys; 

 Chirp subbottom profiler HRG marine mineral surveys; 

 Chirp subbottom profiler HRG renewable energy surveys; 

 Multibeam HRG marine mineral surveys; and 

 Multibeam HRG renewable energy surveys. 

For the non-airgun HRG surveys, even though the individual surveys are typically conducted in 

roughly square nautical mile areas, all of the above tables were presented in a “per block” format to be 

consistent with the airgun surveys. Also, the LOE tables for these non-airgun surveys have been kept in 

that format. 

Each of these “per block” survey results were multiplied by the appropriate LOE to estimate the 

number of incidental takes by species by modeled area for each year. Total annual takes are summarized 

in the following tables in the Attachment to this appendix: 

All Surveys (seismic airgun and non-airgun HRG) 

 Table Attachment E-1: Level A incidental take using Southall criteria 

 Table Attachment E-2: Level A incidental take using historic NMFS criterion 

(180 dB SPL) 

 Table Attachment E-3: Level B incidental take using historic NMFS criterion 

(160 dB SPL) 

All seismic airgun surveys 

 Table Attachment E-4: Level A incidental take using Southall criteria 

 Table Attachment E-5: Level A incidental take using historic NMFS criterion 

(180 dB SPL) 

 Table Attachment E-6: Level B incidental take using historic NMFS criterion 

(160 dB SPL) 

All non-airgun HRG surveys 

 Table Attachment E-7: Level A incidental take using Southall criteria 

 Table Attachment E-8: Level A incidental take using historic NMFS criterion 

(180 dB SPL) 

 Table Attachment E-9: Level B incidental take using historic NMFS criterion 

(160 dB SPL) 
Acoustic Modeling and Marine Mammal Incidental Take Methodology E-69 

Supporting tables for each year and survey type are available on the BOEM website at: http://

www.boem.gov/Oil-and-Gas-Energy-Program/GOMR/GandG.aspx. 

In general, due to their significant LOE and strong transmission signal, for any given year the 

combination of 2D and 3D surveys, account for about 90-95 percent of all takes, while all of the 

non-airgun survey efforts result in less than about 5 percent of takes for any given year. This is due to 

their lower source levels, beam patterns, and significantly lower LOE. 

7.5.2. Discussion of the Uncertainty of the Modeling Effort 

This section briefly discusses the level of uncertainty or error that may be included in the calculations. 

This section addresses the issue in a general way and also discusses the limitations of any similar analysis 

based on the overall intent of the analysis and the safeguards used during its completion. 

The analysis as described in this appendix and Appendix D used the best available state-of-the-art 

acoustic models and databases for determining acoustic propagation and source characteristics. Similarly, 

the marine mammal data (i.e., including density and distribution data, as well as all animal movement 

data) are the best currently available and are constantly being updated and improved as new material and 

data are published. The final computation or software component used was the AIM model. Essentially, 

AIM is a sophisticated and complex record keeping program, which uses correct statistical analyses and 

sampling to integrate the various components that constitute its input (i.e., source parameters, acoustic 

propagation parameters, and the animal distribution and movement parameters) and provide the estimates 

of the impacts to the modeled animals. Each of these analysis tools has been tested and verified against 

known scenarios and each has demonstrated reasonable levels of accuracy based on current theories and 

databases. In 2006, the Center for Independent Experts (CIE) conducted a review and assessment of AIM 

and concluded that AIM is a credible tool for developing application models (Independent System for 

Peer Review, 2006). Additionally, when multiple inputs parameters, data and techniques were available, 

the more conservative value was generally selected, with the result that the analysis overall produced a 

conservative (i.e., high) level of potential impacts based on the knowledge available. 

The task for this analysis was to use the best science available to estimate the potential impacts to 

marine mammals for the proposed action. The goal is to predict potential impacts for a period out to 

10 years, for a variety of sources, locations and times (i.e., seasons), which have only been identified 

generally, in an acoustic propagation environment that changes daily or more frequently depending on the 

weather, with a highly variable and mobile animal population. Currently, the only methodology capable 

of even beginning to capture the variability identified in this task is to use representative conditions or 

averages of these variables to estimate the ultimate impact levels. This was the approach used in this 

analysis and even so, tens and possible hundreds of millions calculations were needed to produce the 

results provided here. Ultimately, the accuracy of the task relies less on the accuracy of the models and 

more on the accuracy of the modeler’s ability to estimate these representative or average conditions. To 

date, probably the best measurement of this need to estimate representative or average conditions is the 

annually reported level of impacts for any given year of operations; as compared to that year’s take 

authorization number. To the best of our knowledge, this has not been done officially, but anecdotal 

information and experience with years of annual reports has shown that typically the number of animals 

observed at sea is less than predicted, and their potential impacts appear lower since they are seldom 

observed near the sources. 

As an example of the difficulty of this process, the following example may provide insight. In this 

example, the only variable allowed to change is the actual local density or distribution near an airgun 

array which is performing a 2D survey of a typical dolphin species. This species may have an average 

density of about one animal per square nautical mile, but on a particular day a large pod of 500 of those 

dolphins has congregated due to a prey species and that pod approaches to about one kilometer from the 

operational airgun array. Obviously, this event could cause more impacts for that day than any average 

calculation would show. However, if the estimated average density of 1 animal per square nautical mile 

is correct, over the average of a season or a year the actual number of impacts would approach the 

estimate because that same pod on average over time would be farther away from the operational source 

for most if not all of the remaining days and the average estimate of impacts for those days would exceed 

reality. 
E-70 Atlantic G&G Programmatic EIS

Finally, it should be noted that the results of this Programmatic EIS are preliminary and more refined 

estimates could be made in the future during the MMPA Incidental Take Authorization (ITA) process for 

individual surveys. At that time, details about acoustic systems, planned tracks and testing periods would 

be better known and could be used to refine the analysis. 

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ATTACHMENT: SUMMARY TABLES OF TOTAL ANNUAL TAKE ESTIMATES Table Attachment E-1 All Surveys (airgun and non-airgun) – Total Annual Level A Takes (number of individuals) Using Southall Crit

Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common Minke Whale 0.000 0.084 0.161 0.013 0.069 0.045 0.021 

Sei Whale 0.002 0.211 0.405 0.035 0.178 0.115 0.057 Bryde's Whale 0.002 0.635 1.240 0.131 0.724 0.529 0.360 Blue Whale 0.000 0.831 1.623 0.164 0.915 0.664 0.439 Fin Whale 0.015 0.021 0.021 0.021 0.021 0.018 0.005 North Atlantic Right Whale 0.002 0.039 0.074 0.011 0.047 0.036 0.025 Humpback Whale 0.000 3.046 5.931 0.567 3.153 2.226 1.402 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked Common Dolphin 4.094 121.807 230.677 24.072 101.335 68.641 29.844 

Pygmy Killer Whale 0.000 0.162 0.313 0.028 0.176 0.114 0.082 Short-Finned Pilot Whale 0.005 11.627 22.508 1.950 82.506 51.948 90.213 Long-Finned Pilot Whale 0.000 59.577 117.528 13.877 79.694 61.037 45.681 Risso’s Dolphin 1.863 372.779 733.668 89.369 503.809 387.135 290.469 Northern Bottlenose Whale 0.000 0.004 0.007 0.001 0.003 0.002 0.001 Pygmy Sperm Whale 0.005 0.006 0.006 0.006 0.087 0.047 0.081 Dwarf Sperm Whale 0.014 2.838 5.583 0.681 4.493 3.333 2.957 Atlantic White-sided Dolphin 0.000 1.347 2.659 0.319 2.039 1.540 1.315 Fraser's Dolphin 0.000 0.209 0.403 0.033 0.162 0.105 0.041 Sowerby's Beaked Whale 0.000 0.000 0.000 0.000 0.006 0.004 0.007 Blainville's Beaked Whale 0.000 1.459 2.816 0.225 1.126 0.731 0.282 Gervais' Beaked Whale 0.000 1.459 2.816 0.225 1.126 0.731 0.282 True's Beaked Whale 0.000 1.459 2.816 0.225 1.126 0.731 0.282 Killer Whale 0.003 0.058 0.106 0.014 0.071 0.045 0.040 Melon-Headed Whale 0.000 0.161 0.313 0.027 0.175 0.113 0.081 Harbor Porpoise 0.001 2.065 3.995 0.339 2.051 1.344 0.886 Sperm Whale 0.001 0.096 0.185 0.016 0.077 0.051 0.021 False Killer Whale 0.000 0.155 0.300 0.027 0.237 0.151 0.158 Pantropical Spotted Dolphin 0.448 136.524 264.052 23.606 132.347 89.822 56.072 Clymene Dolphin 0.214 65.225 126.151 11.278 63.229 42.913 26.789 Striped Dolphin 0.595 528.183 1021.267 87.032 514.183 342.274 224.183 Atlantic Spotted Dolphin 5.399 778.265 1503.662 140.710 773.775 531.263 338.099 Spinner Dolphin 0.002 0.614 1.187 0.106 0.595 0.404 0.252 Rough-Toothed Dolphin 0.010 0.015 0.015 0.015 0.050 0.036 0.048 Bottlenose Dolphin 1.298 16.917 31.297 5.417 37.973 26.119 31.803 Cuvier's Beaked Whale 0.001 10.214 19.711 1.578 7.885 5.120 1.972 

ORDER SIRENIA West Indian Manatee 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORDER CARNIVORA Suborder Pinnipedia Hooded Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Gray Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 
Table Attachment E-2 All Surveys (airgun and non-airgun) – Total Annual Level A Takes (number of individuals) Using Historic NMFS Criter

Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 2

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common Minke Whale 0.000 0.342 0.666 0.064 0.381 0.266 0.187 

Sei Whale 0.000 1.966 3.855 0.417 2.565 1.881 1.477 Bryde's Whale 0.000 1.948 3.820 0.413 2.536 1.858 1.458 Blue Whale 0.001 2.183 4.275 0.452 2.754 2.002 1.541 Fin Whale 0.001 4.401 8.639 0.951 5.898 4.344 3.478 North Atlantic Right Whale 0.002 1.164 2.293 0.271 1.885 1.397 1.299 Humpback Whale 0.003 5.900 11.546 1.210 7.336 5.318 4.047 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked Common Dolphin 1.219 3122.842 6148.048 708.337 4438.213 3318.065 2735.485 

Pygmy Killer Whale 0.000 2.253 4.410 0.463 2.807 2.037 1.551 Short-Finned Pilot Whale 0.013 2354.316 4631.150 524.173 3290.560 2446.252 2005.847 Long-Finned Pilot Whale 0.003 297.403 582.364 61.352 376.214 273.197 211.259 Risso’s Dolphin 0.091 1619.783 3180.578 350.478 2173.534 1603.414 1283.210 Northern Bottlenose Whale 0.000 0.127 0.250 0.029 0.179 0.134 0.110 Pygmy Sperm Whale 0.001 2.372 4.594 0.399 2.217 1.483 0.852 Dwarf Sperm Whale 0.003 14.849 29.009 2.951 17.497 12.585 9.151 Atlantic White-sided Dolphin 0.000 4.668 9.152 0.985 5.987 4.389 3.390 Fraser's Dolphin 0.000 0.243 0.469 0.040 0.218 0.144 0.078 Sowerby's Beaked Whale 0.000 0.203 0.397 0.040 0.242 0.174 0.128 Blainville's Beaked Whale 0.000 39.568 77.313 7.855 47.099 33.812 24.918 Gervais' Beaked Whale 0.000 39.568 77.313 7.855 47.099 33.812 24.918 True's Beaked Whale 0.000 39.568 77.313 7.855 47.099 33.812 24.918 Killer Whale 0.001 1.966 3.844 0.397 2.394 1.727 1.294 Melon-Headed Whale 0.000 2.523 4.943 0.525 3.216 2.343 1.816 Harbor Porpoise 0.002 7.056 13.800 1.430 8.707 6.285 4.780 Sperm Whale 0.000 158.828 309.724 30.401 179.051 126.960 89.385 False Killer Whale 0.000 2.802 5.492 0.590 3.636 2.658 2.087 Pantropical Spotted Dolphin 0.304 447.186 876.533 94.964 580.693 425.651 333.075 Clymene Dolphin 0.145 207.397 406.406 43.850 267.772 195.992 152.835 Striped Dolphin 0.396 2039.424 3993.807 422.639 2575.840 1874.396 1442.044 Atlantic Spotted Dolphin 3.461 2983.891 5852.577 645.633 3954.207 2914.067 2306.571 Spinner Dolphin 0.001 1.951 3.823 0.412 2.519 1.844 1.438 Rough-Toothed Dolphin 0.006 13.762 26.895 2.760 16.679 11.993 8.993 Bottlenose Dolphin 0.938 5978.445 11749.675 1315.320 8208.500 6081.036 4934.402 Cuvier's Beaked Whale 0.000 276.973 541.189 54.986 329.696 236.682 174.425 

ORDER SIRENIA West Indian Manatee 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORDER CARNIVORA Suborder Pinnipedia Hooded Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Gray Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 
Table Attachment E-3 All Surveys (airgun and non-airgun) – Total Annual Level B Takes (number of individuals) Using Historic NMFS Criter

Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 2

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common Minke Whale 0.022 33.550 65.312 6.287 37.298 26.088 18.339 

Sei Whale 0.036 192.672 377.852 40.901 251.373 184.310 144.793 Bryde's Whale 0.036 190.943 374.409 40.440 248.542 182.095 142.935 Blue Whale 0.066 213.999 418.979 44.264 269.881 196.170 150.994 Fin Whale 0.115 431.364 846.749 93.167 578.072 425.755 340.840 North Atlantic Right Whale 0.194 114.092 224.739 26.592 184.766 136.944 127.334 Humpback Whale 0.245 578.293 1131.575 118.608 718.954 521.193 396.647 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked Common Dolphin 119.444 306069.739 602570.182 69424.082 434989.253 325203.591 268104.901 14

Pygmy Killer Whale 0.034 220.825 432.243 45.365 275.139 199.673 151.972 Short-Finned Pilot Whale 1.292 230746.558 453899.015 51374.206 322507.797 239757.144 196593.075 10Long-Finned Pilot Whale 0.262 29148.473 57077.465 6013.098 36872.714 26775.994 20705.467 1Risso’s Dolphin 8.944 158754.967 311728.435 34350.388 213028.049 157150.561 125767.385 6Northern Bottlenose Whale 0.000 12.462 24.544 2.829 17.568 13.169 10.740 Pygmy Sperm Whale 0.112 232.504 450.223 39.071 217.329 145.381 83.499 Dwarf Sperm Whale 0.336 1455.336 2843.191 289.246 1714.850 1233.490 896.926 Atlantic White-sided Dolphin 0.003 457.486 896.992 96.503 586.760 430.138 332.240 Fraser's Dolphin 0.035 23.774 45.946 3.929 21.400 14.120 7.671 Sowerby's Beaked Whale 0.002 19.913 38.908 3.959 23.676 17.011 12.506 Blainville's Beaked Whale 0.002 3878.018 7577.417 769.886 4616.214 3313.885 2442.204 Gervais' Beaked Whale 0.002 3878.018 7577.417 769.886 4616.214 3313.885 2442.204 True's Beaked Whale 0.003 3878.019 7577.418 769.887 4616.214 3313.886 2442.205 Killer Whale 0.051 192.653 376.717 38.928 234.603 169.297 126.828 Melon-Headed Whale 0.036 247.292 484.433 51.498 315.189 229.642 177.968 Harbor Porpoise 0.154 691.538 1352.566 140.176 853.358 615.982 468.490 Sperm Whale 0.018 15566.727 30356.018 2979.633 17548.762 12443.391 8760.616 False Killer Whale 0.039 274.585 538.272 57.864 356.340 260.532 204.520 Pantropical Spotted Dolphin 29.753 43828.703 85909.037 9307.463 56913.689 41718.028 32644.651 1Clymene Dolphin 14.215 20326.942 39831.854 4297.704 26244.328 19209.194 14979.406 Striped Dolphin 38.853 199883.937 391433.034 41422.836 252458.092 183709.544 141334.709 8Atlantic Spotted Dolphin 339.182 292451.134 573611.088 63278.489 387551.801 285607.693 226067.062 12Spinner Dolphin 0.131 191.216 374.705 40.424 246.883 180.701 140.913 Rough-Toothed Dolphin 0.555 1348.832 2636.003 270.481 1634.722 1175.421 881.440 Bottlenose Dolphin 91.950 585947.347 1151585.614 128914.529 804515.124 596002.320 483620.734 26Cuvier's Beaked Whale 0.016 27146.128 53041.920 5389.204 32313.495 23197.195 17095.430 1

ORDER SIRENIA West Indian Manatee 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORDER CARNIVORA Suborder Pinnipedia Hooded Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Gray Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 
Table Attachment E-4 All Seismic Airgun Surveys – Total Annual Level A Takes (number of individuals) Using Southall Criteria Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common Minke Whale 0.000 0.083 0.161 0.013 0.069 0.044 0.021 

Sei Whale 0.000 0.208 0.402 0.032 0.176 0.113 0.057 Bryde's Whale 0.000 0.632 1.237 0.128 0.721 0.526 0.359 Blue Whale 0.000 0.831 1.622 0.164 0.915 0.663 0.439 Fin Whale 0.000 0.000 0.000 0.000 0.000 0.000 0.000 North Atlantic Right Whale 0.000 0.036 0.071 0.008 0.045 0.034 0.024 Humpback Whale 0.000 3.046 5.931 0.567 3.153 2.226 1.402 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked Common Dolphin 0.000 116.584 225.454 18.848 96.111 64.095 28.714 

Pygmy Killer Whale 0.000 0.161 0.312 0.027 0.175 0.113 0.081 Short-Finned Pilot Whale 0.000 11.616 22.498 1.939 82.495 51.938 90.208 Long-Finned Pilot Whale 0.000 59.577 117.528 13.877 79.694 61.037 45.681 Risso’s Dolphin 0.000 370.550 731.439 87.140 501.580 385.115 290.103 Northern Bottlenose Whale 0.000 0.004 0.007 0.001 0.003 0.002 0.001 Pygmy Sperm Whale 0.000 0.000 0.000 0.000 0.081 0.041 0.080 Dwarf Sperm Whale 0.000 2.819 5.564 0.662 4.474 3.315 2.953 Atlantic White-sided Dolphin 0.000 1.347 2.659 0.319 2.039 1.540 1.315 Fraser's Dolphin 0.000 0.208 0.402 0.032 0.161 0.105 0.041 Sowerby's Beaked Whale 0.000 0.000 0.000 0.000 0.006 0.004 0.007 Blainville's Beaked Whale 0.000 1.459 2.816 0.225 1.126 0.731 0.282 Gervais' Beaked Whale 0.000 1.459 2.816 0.225 1.126 0.731 0.282 True's Beaked Whale 0.000 1.459 2.816 0.225 1.126 0.731 0.282 Killer Whale 0.000 0.052 0.100 0.008 0.065 0.040 0.036 Melon-Headed Whale 0.000 0.161 0.312 0.027 0.175 0.113 0.081 Harbor Porpoise 0.000 2.064 3.995 0.338 2.051 1.344 0.886 Sperm Whale 0.000 0.095 0.184 0.015 0.076 0.050 0.021 False Killer Whale 0.000 0.155 0.300 0.026 0.236 0.151 0.158 Pantropical Spotted Dolphin 0.000 135.938 263.432 22.986 131.727 89.279 55.904 Clymene Dolphin 0.000 64.945 125.855 10.982 62.933 42.653 26.708 Striped Dolphin 0.000 527.416 1020.455 86.220 513.371 341.562 223.973 Atlantic Spotted Dolphin 0.000 771.308 1496.301 133.348 766.414 524.822 336.201 Spinner Dolphin 0.000 0.611 1.184 0.103 0.592 0.401 0.251 Rough-Toothed Dolphin 0.000 0.000 0.000 0.000 0.036 0.023 0.043 Bottlenose Dolphin 0.000 14.775 28.936 3.056 35.612 24.127 30.763 Cuvier's Beaked Whale 0.000 10.213 19.709 1.577 7.883 5.119 1.972 

ORDER SIRENIA West Indian Manatee 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORDER CARNIVORA Suborder Pinnipedia Hooded Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Gray Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 
Table Attachment E-5 All Seismic Airgun Surveys – Total Annual Level A Takes (number of individuals) Using Historic NMFS Criterion (

Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 2

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common Minke Whale 0.000 0.342 0.666 0.064 0.380 0.266 0.187 

Sei Whale 0.000 1.965 3.855 0.417 2.564 1.880 1.476 Bryde's Whale 0.000 1.948 3.820 0.412 2.535 1.857 1.457 Blue Whale 0.000 2.182 4.274 0.451 2.753 2.000 1.539 Fin Whale 0.000 4.400 8.638 0.949 5.896 4.342 3.474 North Atlantic Right Whale 0.000 1.162 2.290 0.269 1.883 1.395 1.294 Humpback Whale 0.000 5.897 11.542 1.207 7.332 5.314 4.043 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked Common Dolphin 0.000 3121.383 6146.553 706.842 4436.718 3316.557 2733.398 

Pygmy Killer Whale 0.000 2.253 4.410 0.462 2.807 2.037 1.549 Short-Finned Pilot Whale 0.000 2354.300 4631.133 524.156 3290.543 2446.116 2004.600 Long-Finned Pilot Whale 0.000 297.400 582.360 61.349 376.210 273.181 211.129 Risso’s Dolphin 0.000 1619.672 3180.466 350.367 2173.422 1603.231 1282.343 Northern Bottlenose Whale 0.000 0.127 0.250 0.029 0.179 0.134 0.110 Pygmy Sperm Whale 0.000 2.371 4.592 0.397 2.216 1.482 0.851 Dwarf Sperm Whale 0.000 14.844 29.005 2.947 17.492 12.581 9.146 Atlantic White-sided Dolphin 0.000 4.668 9.152 0.985 5.987 4.389 3.388 Fraser's Dolphin 0.000 0.242 0.468 0.039 0.218 0.143 0.078 Sowerby's Beaked Whale 0.000 0.203 0.397 0.040 0.242 0.174 0.128 Blainville's Beaked Whale 0.000 39.568 77.313 7.855 47.099 33.810 24.904 Gervais' Beaked Whale 0.000 39.568 77.313 7.855 47.099 33.810 24.904 True's Beaked Whale 0.000 39.568 77.313 7.855 47.099 33.810 24.904 Killer Whale 0.000 1.965 3.843 0.396 2.393 1.727 1.293 Melon-Headed Whale 0.000 2.523 4.942 0.525 3.215 2.342 1.814 Harbor Porpoise 0.000 7.054 13.798 1.428 8.705 6.283 4.777 Sperm Whale 0.000 158.828 309.723 30.401 179.051 126.956 89.342 False Killer Whale 0.000 2.801 5.491 0.590 3.635 2.658 2.085 Pantropical Spotted Dolphin 0.000 446.741 876.082 94.513 580.242 425.213 332.719 Clymene Dolphin 0.000 207.184 406.191 43.634 267.556 195.783 152.671 Striped Dolphin 0.000 2038.848 3993.224 422.056 2575.257 1873.787 1441.135 Atlantic Spotted Dolphin 0.000 2978.964 5847.582 640.637 3949.211 2909.316 2303.489 Spinner Dolphin 0.000 1.949 3.821 0.410 2.517 1.842 1.436 Rough-Toothed Dolphin 0.000 13.755 26.888 2.752 16.672 11.986 8.985 Bottlenose Dolphin 0.000 5977.039 11748.210 1313.855 8207.035 6079.369 4930.570 Cuvier's Beaked Whale 0.000 276.973 541.189 54.986 329.696 236.673 174.331 

ORDER SIRENIA West Indian Manatee 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORDER CARNIVORA Suborder Pinnipedia Hooded Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Gray Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 
Table Attachment E-6 All Seismic Airgun Surveys – Total Annual Level B Takes (number of individuals) Using Historic NMFS Criterion (

Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 2

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common Minke Whale 0.000 33.522 65.282 6.257 37.268 26.060 18.319 

Sei Whale 0.000 192.625 377.801 40.850 251.322 184.255 144.677 Bryde's Whale 0.000 190.896 374.359 40.389 248.492 182.040 142.818 Blue Whale 0.000 213.901 418.875 44.161 269.778 196.066 150.850 Fin Whale 0.000 431.204 846.583 93.001 577.905 425.583 340.531 North Atlantic Right Whale 0.000 240.877 475.584 56.846 361.004 272.896 230.884 Humpback Whale 0.000 577.964 1131.230 118.264 718.609 520.862 396.288 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked Common Dolphin 0.000 305926.755 602423.698 69277.598 434842.769 325055.721 267900.300 14

Pygmy Killer Whale 0.000 220.776 432.193 45.316 275.090 199.618 151.862 Short-Finned Pilot Whale 0.000 230744.930 453897.344 51372.535 322506.126 239743.839 196470.811 10Long-Finned Pilot Whale 0.000 29148.152 57077.138 6012.771 36872.388 26774.497 20692.778 1Risso’s Dolphin 0.000 158744.009 311717.478 34339.430 213017.091 157132.663 125682.450 6Northern Bottlenose Whale 0.000 12.462 24.544 2.829 17.568 13.169 10.733 Pygmy Sperm Whale 0.000 232.353 450.073 38.920 217.178 145.240 83.426 Dwarf Sperm Whale 0.000 1454.885 2842.740 288.795 1714.399 1233.034 896.367 Atlantic White-sided Dolphin 0.000 457.481 896.987 96.497 586.754 430.117 332.072 Fraser's Dolphin 0.000 23.717 45.882 3.865 21.337 14.063 7.641 Sowerby's Beaked Whale 0.000 19.910 38.905 3.957 23.674 17.008 12.499 Blainville's Beaked Whale 0.000 3878.016 7577.415 769.884 4616.211 3313.759 2440.889 Gervais' Beaked Whale 0.000 3878.016 7577.415 769.884 4616.211 3313.759 2440.889 True's Beaked Whale 0.000 3878.016 7577.415 769.884 4616.211 3313.759 2440.889 Killer Whale 0.000 192.589 376.649 38.861 234.535 169.229 126.733 Melon-Headed Whale 0.000 247.240 484.381 51.446 315.137 229.581 177.832 Harbor Porpoise 0.000 691.367 1352.385 139.995 853.177 615.792 468.191 Sperm Whale 0.000 15566.706 30355.996 2979.611 17548.740 12442.986 8756.403 False Killer Whale 0.000 274.527 538.213 57.806 356.282 260.465 204.367 Pantropical Spotted Dolphin 0.000 43785.058 85864.840 9263.266 56869.492 41675.091 32609.770 1Clymene Dolphin 0.000 20306.091 39810.739 4276.589 26223.212 19188.734 14963.300 Striped Dolphin 0.000 199827.536 391375.882 41365.683 252400.939 183649.880 141245.653 8Atlantic Spotted Dolphin 0.000 291968.246 573121.475 62788.875 387062.188 285142.042 225764.925 12Spinner Dolphin 0.000 191.026 374.513 40.231 246.691 180.515 140.765 Rough-Toothed Dolphin 0.000 1348.103 2635.268 269.746 1633.987 1174.707 880.655 Bottlenose Dolphin 0.000 585809.587 1151442.029 128770.944 804371.539 595838.922 483245.127 26Cuvier's Beaked Whale 0.000 27146.110 53041.902 5389.186 32313.477 23196.314 17086.222 1

ORDER SIRENIA West Indian Manatee 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORDER CARNIVORA Suborder Pinnipedia Hooded Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 

Gray Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Harbor Seal 0.000 0.000 0.000 0.000 0.000 0.000 0.000 
Table Attachment E-7 All Non-Airgun HRG Surveys – Total Annual Level A Takes (number of individuals) Using Southall Criteria Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 2

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common Minke Whale 0.0003 0.0004 0.0004 0.0004 0.0004 0.0003 0.0000 

Sei Whale 0.0020 0.0024 0.0024 0.0024 0.0024 0.0021 0.0004 Bryde's Whale 0.0023 0.0030 0.0030 0.0030 0.0030 0.0027 0.0007 Blue Whale 0.0002 0.0005 0.0005 0.0005 0.0005 0.0005 0.0003 Fin Whale 0.0155 0.0208 0.0208 0.0208 0.0208 0.0185 0.0053 North Atlantic Right Whale 0.0021 0.0026 0.0026 0.0026 0.0026 0.0022 0.0005 Humpback Whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked Common Dolphin 4.0936 5.2235 5.2235 5.2235 5.2235 4.5460 1.1299 

Pygmy Killer Whale 0.0004 0.0010 0.0010 0.0010 0.0010 0.0009 0.0006 Short-Finned Pilot Whale 0.0053 0.0106 0.0106 0.0106 0.0106 0.0106 0.0053 Long-Finned Pilot Whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Risso’s Dolphin 1.8630 2.2287 2.2287 2.2287 2.2287 2.0205 0.3658 Northern Bottlenose Whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Pygmy Sperm Whale 0.0048 0.0064 0.0064 0.0064 0.0064 0.0059 0.0016 Dwarf Sperm Whale 0.0145 0.0192 0.0192 0.0192 0.0192 0.0178 0.0047 Atlantic White-sided Dolphin 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Fraser's Dolphin 0.0001 0.0003 0.0004 0.0004 0.0004 0.0003 0.0003 Sowerby's Beaked Whale 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0000 Blainville's Beaked Whale 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0000 Gervais' Beaked Whale 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0000 True's Beaked Whale 0.0002 0.0002 0.0002 0.0002 0.0002 0.0002 0.0000 Killer Whale 0.0025 0.0061 0.0061 0.0061 0.0061 0.0058 0.0036 Melon-Headed Whale 0.0001 0.0004 0.0004 0.0004 0.0004 0.0003 0.0003 Harbor Porpoise 0.0005 0.0007 0.0007 0.0007 0.0007 0.0006 0.0002 Sperm Whale 0.0008 0.0009 0.0009 0.0009 0.0009 0.0008 0.0001 False Killer Whale 0.0001 0.0004 0.0004 0.0004 0.0004 0.0003 0.0003 Pantropical Spotted Dolphin 0.4477 0.5868 0.6200 0.6200 0.6200 0.5432 0.1677 Clymene Dolphin 0.2139 0.2803 0.2962 0.2962 0.2962 0.2595 0.0801 Striped Dolphin 0.5954 0.7674 0.8121 0.8121 0.8121 0.7114 0.2107 Atlantic Spotted Dolphin 5.3991 6.9574 7.3614 7.3614 7.3614 6.4414 1.8980 Spinner Dolphin 0.0020 0.0026 0.0028 0.0028 0.0028 0.0024 0.0008 Rough-Toothed Dolphin 0.0099 0.0145 0.0145 0.0145 0.0145 0.0134 0.0047 Bottlenose Dolphin 1.2977 2.1422 2.3608 2.3608 2.3608 1.9922 1.0400 Cuvier's Beaked Whale 0.0013 0.0015 0.0015 0.0015 0.0015 0.0013 0.0003 

ORDER SIRENIA West Indian Manatee 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 ORDER CARNIVORA Suborder Pinnipedia Hooded Seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 

Gray Seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Harbor Seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 
Table Attachment E-8 All Non-Airgun HRG Surveys – Total Annual Level A Takes (number of individuals) Using Historic NMFS Criterion 

Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common Minke Whale 0.0002 0.0003 0.0003 0.0003 0.0003 0.0003 0.0002 

Sei Whale 0.0004 0.0005 0.0005 0.0005 0.0005 0.0006 0.0012 Bryde's Whale 0.0004 0.0005 0.0005 0.0005 0.0005 0.0006 0.0012 Blue Whale 0.0007 0.0010 0.0011 0.0011 0.0011 0.0011 0.0015 Fin Whale 0.0012 0.0016 0.0017 0.0017 0.0017 0.0018 0.0031 North Atlantic Right Whale 0.0020 0.0025 0.0025 0.0025 0.0025 0.0027 0.0051 Humpback Whale 0.0025 0.0034 0.0035 0.0035 0.0035 0.0034 0.0037 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked Common Dolphin 1.2187 1.4589 1.4946 1.4946 1.4946 1.5087 2.0876 

Pygmy Killer Whale 0.0004 0.0005 0.0005 0.0005 0.0005 0.0006 0.0011 Short-Finned Pilot Whale 0.0132 0.0166 0.0171 0.0171 0.0171 0.1358 1.2475 Long-Finned Pilot Whale 0.0027 0.0033 0.0033 0.0033 0.0033 0.0153 0.1295 Risso’s Dolphin 0.0913 0.1118 0.1118 0.1118 0.1118 0.1826 0.8666 Northern Bottlenose Whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0001 Pygmy Sperm Whale 0.0011 0.0015 0.0015 0.0015 0.0015 0.0014 0.0007 Dwarf Sperm Whale 0.0034 0.0046 0.0046 0.0046 0.0046 0.0046 0.0057 Atlantic White-sided Dolphin 0.0000 0.0001 0.0001 0.0001 0.0001 0.0002 0.0017 Fraser's Dolphin 0.0004 0.0006 0.0007 0.0007 0.0007 0.0006 0.0003 Sowerby's Beaked Whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0001 Blainville's Beaked Whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0013 0.0134 Gervais' Beaked Whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0013 0.0134 True's Beaked Whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0013 0.0134 Killer Whale 0.0005 0.0007 0.0007 0.0007 0.0007 0.0007 0.0010 Melon-Headed Whale 0.0004 0.0005 0.0005 0.0005 0.0005 0.0006 0.0014 Harbor Porpoise 0.0016 0.0018 0.0018 0.0018 0.0018 0.0019 0.0031 Sperm Whale 0.0002 0.0002 0.0002 0.0002 0.0002 0.0041 0.0430 False Killer Whale 0.0004 0.0006 0.0006 0.0006 0.0006 0.0007 0.0016 Pantropical Spotted Dolphin 0.3036 0.4453 0.4509 0.4509 0.4509 0.4381 0.3559 Clymene Dolphin 0.1450 0.2127 0.2154 0.2154 0.2154 0.2088 0.1643 Striped Dolphin 0.3964 0.5755 0.5831 0.5831 0.5831 0.6088 0.9086 Atlantic Spotted Dolphin 3.4607 4.9269 4.9955 4.9955 4.9955 4.7511 3.0827 Spinner Dolphin 0.0013 0.0019 0.0020 0.0020 0.0020 0.0019 0.0015 Rough-Toothed Dolphin 0.0057 0.0074 0.0075 0.0075 0.0075 0.0073 0.0080 Bottlenose Dolphin 0.9382 1.4056 1.4650 1.4650 1.4650 1.6672 3.8323 Cuvier's Beaked Whale 0.0002 0.0002 0.0002 0.0002 0.0002 0.0090 0.0939 

ORDER SIRENIA West Indian Manatee 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 ORDER CARNIVORA Suborder Pinnipedia Hooded Seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 

Gray Seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Harbor Seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 
Table Attachment E-9 All Non-Airgun HRG Surveys – Total Annual Level B Takes (number of individuals) Using Historic NMFS Criterion 

Year Marine Mammal 2012 2013 2014 2015 2016 2017 2018 

ORDER CETACEA Suborder Mysticeti (Baleen Whales) Common Minke Whale 0.0225 0.0287 0.0300 0.0300 0.0300 0.0282 0.0200 

Sei Whale 0.0358 0.0476 0.0511 0.0511 0.0511 0.0557 0.1152 Bryde's Whale 0.0355 0.0470 0.0505 0.0505 0.0505 0.0553 0.1169 Blue Whale 0.0659 0.0980 0.1037 0.1037 0.1037 0.1048 0.1448 Fin Whale 0.1153 0.1598 0.1665 0.1665 0.1665 0.1722 0.3083 North Atlantic Right Whale 0.1945 0.2461 0.2491 0.2491 0.2491 0.2690 0.5016 Humpback Whale 0.2454 0.3285 0.3444 0.3444 0.3444 0.3313 0.3597 

Suborder Odontoceti (Toothed Whales, Dolphins, and Porpoises) Short-beaked Common Dolphin 119.4440 142.9833 146.4839 146.4839 146.4839 147.8699 204.6009 

Pygmy Killer Whale 0.0345 0.0494 0.0494 0.0494 0.0494 0.0549 0.1097 Short-Finned Pilot Whale 1.2920 1.6287 1.6711 1.6711 1.6711 13.3054 122.2637 Long-Finned Pilot Whale 0.2621 0.3201 0.3267 0.3267 0.3267 1.4975 12.6893 Risso’s Dolphin 8.9444 10.9577 10.9577 10.9577 10.9577 17.8981 84.9354 Northern Bottlenose Whale 0.0000 0.0000 0.0000 0.0000 0.0000 0.0006 0.0063 Pygmy Sperm Whale 0.1119 0.1503 0.1503 0.1503 0.1503 0.1410 0.0732 Dwarf Sperm Whale 0.3358 0.4508 0.4508 0.4508 0.4508 0.4557 0.5592 Atlantic White-sided Dolphin 0.0027 0.0055 0.0055 0.0055 0.0055 0.0208 0.1680 Fraser's Dolphin 0.0345 0.0568 0.0637 0.0637 0.0637 0.0575 0.0304 Sowerby's Beaked Whale 0.0023 0.0026 0.0026 0.0026 0.0026 0.0030 0.0073 Blainville's Beaked Whale 0.0023 0.0026 0.0026 0.0026 0.0026 0.1259 1.3153 Gervais' Beaked Whale 0.0023 0.0026 0.0026 0.0026 0.0026 0.1259 1.3153 True's Beaked Whale 0.0026 0.0032 0.0032 0.0032 0.0032 0.1265 1.3156 Killer Whale 0.0509 0.0642 0.0678 0.0678 0.0678 0.0680 0.0952 Melon-Headed Whale 0.0361 0.0525 0.0525 0.0525 0.0525 0.0604 0.1362 Harbor Porpoise 0.1543 0.1717 0.1812 0.1812 0.1812 0.1894 0.2990 Sperm Whale 0.0182 0.0215 0.0215 0.0215 0.0215 0.4051 4.2127 False Killer Whale 0.0389 0.0582 0.0582 0.0582 0.0582 0.0674 0.1524 Pantropical Spotted Dolphin 29.7529 43.6445 44.1968 44.1968 44.1968 42.9366 34.8805 Clymene Dolphin 14.2145 20.8513 21.1152 21.1152 21.1152 20.4600 16.1068 Striped Dolphin 38.8529 56.4013 57.1529 57.1529 57.1529 59.6638 89.0555 Atlantic Spotted Dolphin 339.1818 482.8880 489.6133 489.6133 489.6133 465.6510 302.1377 Spinner Dolphin 0.1306 0.1899 0.1924 0.1924 0.1924 0.1862 0.1484 Rough-Toothed Dolphin 0.5554 0.7281 0.7355 0.7355 0.7355 0.7138 0.7853 Bottlenose Dolphin 91.9501 137.7600 143.5851 143.5851 143.5851 163.3981 375.6071 Cuvier's Beaked Whale 0.0158 0.0181 0.0181 0.0181 0.0181 0.8810 9.2072 

ORDER SIRENIA West Indian Manatee 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 ORDER CARNIVORA Suborder Pinnipedia Hooded Seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 

Gray Seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 Harbor Seal 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 0.0000 
APPENDIX F 

 

PHYSICAL AND ENVIRONMENTAL SETTINGS

Physical and Environmental Settings F-iii

TABLE OF CONTENTS 

Page 

1. GEOGRAPHY AND GEOLOGY .................................................................................................... F-1

1.1. Regional Geologic Description............................................................................................... F-1

1.2. Geologic History and Sedimentary Basins ............................................................................. F-4

1.3. Sediments................................................................................................................................ F-6

2. PHYSICAL OCEANOGRAPHY ..................................................................................................... F-8

3. WATER QUALITY........................................................................................................................ F-10

4. METEOROLOGY AND AIR QUALITY ...................................................................................... F-11

5. ACOUSTIC ENVIRONMENT ...................................................................................................... F-13

6. REFERENCES CITED................................................................................................................... F-13

Physical and Environmental Settings F-v

LIST OF FIGURES 

Page 

Figure F-1. Submarine Physiographic Features in the Area of Interest................................................. F-2

Figure F-2. Bathymetry in the Area of Interest...................................................................................... F-3

Figure F-3. Geologic Time Scale........................................................................................................... F-4

Figure F-4. Major Geologic Basins along the Atlantic Coast................................................................ F-5

Figure F-5. Distribution of Surficial Sediment Types in the Area of Interest ....................................... F-7

Figure F-6. Loop Current (Gulf of Mexico) and Gulf Stream (Atlantic Coast) Locations Based 

on Trajectories of Near-surface Drifting Buoys from 1978-2003....................................... F-8

Physical and Environmental Settings F-1

1. GEOGRAPHY AND GEOLOGY 

This section provides a regional geologic description of the Area of Interest (AOI). Additional 

geological background information is provided in a literature synthesis by White (2011). 

1.1. REGIONAL GEOLOGIC DESCRIPTION

The AOI encompasses Atlantic waters from the shoreline (excluding estuaries) to 350 nmi (648 km) 

offshore and from the mouth of Delaware Bay (38°51’ N) to Cape Canaveral, Florida (28°N). The region 

has a mix of depositional and erosional environments and is greatly influenced by a prominent ocean 

current system, the Gulf Stream. Physiographically, the AOI includes the southern portion of the 

Mid-Atlantic Bight (MAB) from the mouth of Delaware Bay south to Cape Hatteras, North Carolina, plus 

all of the South Atlantic Bight (SAB) extending from Cape Hatteras to just south of Cape Canaveral, 

Florida (Figure F-1). The MAB and SAB differ physiographically; the MAB has a classic continental 

shelf-slope-rise sequence, while the SAB has a terrace-like sequence with several prominent features as 

discussed below and shown in Figure F-1. 

The MAB has a broad continental shelf, with the 100-m (330-ft) water-depth contour generally 

coinciding with the shelf break. Offshore Norfolk, Virginia, the continental shelf is approximately 

55-125 km (30-68 nmi) wide, with the change from gradual to steep topographic relief at the shelf break 

generally occurring at depths of 40-160 m (130-525 ft) (Tucholke, 1987). Bathymetry in the AOI is 

shown in Figure F-2. The continental slope, which has an average gradient between 4o and 11o, begins 

seaward of the shelf break (Heezen et al., 1959). The continental rise begins at a depth of approximately 

2,000 m (6,560 ft). The MAB shelf is incised with deep canyons and valleys. Some canyons were eroded 

by rivers during lower stands of sea level, but most were formed via other erosional processes, such as 

slides, debris flows, and turbidity currents (Uchupi, 1968; Malahoff et al., 1980; Tucholke, 1987). There 

are three major canyons in the AOI (Baltimore, Washington, and Norfolk) and several minor canyons 

(Warr, Accomac, Hull, Keller, Hatteras, and Pamlico) (Figure F-1). 

The seafloor in the SAB is divided into two distinct bathymetric areas: the Florida-Hatteras Shelf and 

the Blake Plateau (Figure F-1), which are connected by the gently dipping Florida-Hatteras Slope 

(Popenoe, 1981; Shor and McClennen, 1988). The Florida-Hatteras Shelf is a shallow, extremely flat 

inner shelf with water depths less than 100 m (330 ft) and a gradient less than 1:1,000 (Heezen et al., 

1959; Shepard, 1973). Off Cape Hatteras, the shelf is narrow (~45 km [~24 nmi]), then broadens to over 

105 km (57 nmi) offshore Cape Fear (Figure F-1) (Newton et al., 1971). Off the Georgia coast, the 

Florida-Hatteras Shelf extends nearly 150 km (81 nmi) at its greatest width before narrowing again to less 

than 60 km (32 nmi) off Cape Canaveral (Figure F-1). The shelf break generally occurs in water depths 

of approximately 40-80 m (130-260 ft) offshore northeastern Florida (Macintyre and Milliman, 1970). 

From the edge of the shallow shelf, the Florida-Hatteras Slope gently transitions down about 60 m 

(200 ft) onto the Blake Plateau, a broad, flat sedimentary basin. The slope is smooth and uniform with a 

seaward slope of approximately 1o (Tucholke, 1987). Shelf-edge ridges, or reefs, occur near the top of the 

slope, and the upper slope is smooth and largely devoid of submarine canyons. Blake Plateau is an 

intermediate depth outer shelf where water depths range from approximately 700-1,100 m 

(2,300-3,600 ft). There are numerous terrace-like features and elongated depressions (some with 

deepwater coral mounds) along the base of the Florida-Hatteras slope, although the Blake Plateau 

generally has a smooth surface (Stetson et al., 1962, 1969; Milliman et al., 1967). The western and 

northern portions of the Plateau have a series of deep elongated and flat-bottomed erosional depressions 

caused by scouring by the Gulf Stream and other currents. The Florida-Hatteras slope and the terraces 

and depressions on the Blake Plateau are attributed to Gulf Stream erosion (Tucholke, 1987). 
F-2 Atlantic G&G Programmatic EIS 

Figure F-1. Submarine Physiographic Features in the Area of Interest. 
Physical and Environmental Settings F-3

Figure F-2. Bathymetry in the Area of Interest. 
F-4 Atlantic G&G Programmatic EIS 

The Charleston Bump, located offshore Charleston, South Carolina (Figure F-1) and identified by the 

recurving 500-600 m (1,640-1,969 ft) isobaths (Bane and Brooks, 1979), is a distinctive feature of the 

SAB. It presents prominent bottom relief on a flat seafloor located in 400-700 m (1,312-2,297 ft) water 

depth, causing an offshore deflection of the Gulf Stream’s path and producing meanders, eddies, and 

upwelling over the continental shelf in this area (Bane, 1983; Sedberry et al., 2001). 

1.2. GEOLOGIC HISTORY AND SEDIMENTARY BASINS

The Atlantic and Gulf coasts of North America are situated along a passive continental margin 

formed by the break up and pull-apart of the supercontinent Pangea during the Triassic-Jurassic periods 

during formation of the incipient Atlantic basin (Figure F-3). Continental rifting was accompanied by 

the deposition of red beds and volcanic rocks during the Triassic period followed by marine incursions 

into rift basins during the middle and late Jurassic period when deposition of evaporates took place along 

the Atlantic margin from Newfoundland to the SAB (Figure F-4). 

Figure F-3. Geologic Time Scale (Guccione and Zachary, 2000). 

A passive continental margin is one where the continent and adjacent ocean floor are on the same 

tectonic plate. Passive continental margins are characterized by subsidence, erosion, and thick sediment 

accumulations leading to the development of the characteristic continental margin sequence: continental 

shelf, continental slope, and continental rise (Kennett, 1982). This type of margin experiences little, if 

any, volcanic or earthquake activity after initial formation of the basin. Because these margins are found 

along the east coasts of North and South America and the west coasts of Europe and Africa, they are also 

known as “Atlantic-type” margins. 
Physical and Environmental Settings F-5

Figure F-4. Major Geologic Basins along the Atlantic Coast. 
F-6 Atlantic G&G Programmatic EIS 

Sedimentary basins are areas of the Earth's crust with a history of subsidence and within which 

sediments accumulate forming stratigraphic successions. The stratigraphy of each basin is controlled 

primarily by large-scale events, such as tectonic activity, climate changes, and eustatic sea-level change. 

The mechanisms that produce sedimentary basins are lithospheric stretching, flexuring of the 

oceanic-continental lithosphere, and strike-slip faulting. Sedimentary basins develop within plates 

(intraplate basins) or at their edges (interplate basins). Intraplate basins can develop on both continental 

and oceanic crust; interplate basins can form at passive margins where new oceanic crust is being created, 

as well as destructive and conservative margins. 

Figure F-4 illustrates major geologic basins along the Atlantic coast that are defined by seismic 

surveys. Underlying the Blake Plateau are two deep sedimentary basins with sediment accumulations up 

to 13 km (8 mi) thick that have no surface physiographic expression: the Carolina Trough and the Blake 

Plateau Basin (Figure F-4). The Carolina Trough exhibits salt diapirism and is located below the 

continental slope and upper rise off North and South Carolina. The Blake Plateau Basin is located below 

the southern portion of Blake Plateau to the east of Georgia and northern Florida. The Southeast Georgia 

Embayment is a deep sedimentary basin located beneath the Blake Plateau where sediment thickness can 

be as much as 3.4 km (2.1 mi); it also has no surface physiographic expression. 

1.3. SEDIMENTS

Unconsolidated sediment, primarily sand, silt, clay, and some gravel, covers much of the continental 

shelf and slope of both the MAB and SAB (Figure F-5). The MAB shelf is overlain by a mantle of sand 

approximately 20 m (65 ft) thick, with some areas characterized by linear sand ridges and swales. Rivers 

draining into the MAB carry little sediment offshore because of sediment being trapped in estuaries or 

coastal marshes, resulting in coarse sediments on the shelf (Milliman and Meade, 1983). Tucholke (1987) 

attributes the coarse sediments on the shelf to the winnowing out of fine-grained materials and their 

transport either shoreward into estuaries or off the shelf via submarine canyons onto the continental slope. 

On the Mid-Atlantic continental slope, sediments tend to be silt and clay mixtures with interspersed, 

localized sandy areas (Milliman et al., 1972; Ray et al., 1980). Slope sediments are highly variable, 

consisting mainly of sandy silts on the upper slope and silts and clays on the lower slope 

(McGregor, 1983). Fine-grained biogenic calcareous sediments predominate seaward of the 3,000-m 

(9,843-ft) isobath (Amato, 1994). 

Late Jurassic (approximately 190 million years ago) carbonate sediments and reefs of the Florida 

Platform form the shelf off the northern Florida coast and the Carolina Platform off the North Carolina 

coast (Figure F-5). Terrigenous clastic sediments of Tertiary age prograded across the Florida-Hatteras 

shelf (Figure F-4) to form a thick sedimentary wedge over these platforms that are truncated by the Gulf 

Stream, which scours the inner part of the Blake Plateau nearly clean of sediments. The distribution of 

continental shelf and slope bottom sediments in the SAB are much more complex than those found in 

other areas (Amato, 1994). A thick layer of phosphoritic sediment, whose thickness varies widely, is 

covered by a thin layer of carbonate sand over much of the Blake Plateau. The thin layer of sand, 

generally less than 5 m (15 ft) thick, covers most of the shelf surface. Hard substrate, such as cemented 

sand, that can range from smooth outcrops to rough bottoms with relief up to 15 m (50 ft) occurs in places 

where the sand cover is absent. Accumulation of sediment on the Blake Plateau has not kept pace with 

the rate of subsidence because the Plateau lies beneath and east of the Gulf Stream along the east side on 

the inner shelf, so deposition of coastal sediments is precluded (Amato, 1994). 

Sand and gravel layers in the SAB are much thinner than those found north of Cape Hatteras, and 

rock outcrops are common. The northern areas are characterized by quartz sands while the southern areas 

of the SAB have higher carbonate content. Continental shelf sands are remnants of delta and riverine 

sediments. Sediments on the outer shelf of the SAB tend to be medium to coarse-grained sand (Pilkey et 

al., 1979). Sediments on the continental slope are primarily composed of silt and clay (Tucholke, 1987). 
Physical and Environmental Settings F-7

Figure F-5. Distribution of Surficial Sediment Types in the Area of Interest (Poppe et al., 2005). 
F-8 Atlantic G&G Programmatic EIS 

2. PHYSICAL OCEANOGRAPHY 

This section provides a regional description of the physical oceanography in the AOI. Additional 

background information is provided in a literature synthesis by Voulgaris (2011). 

The major currents along the Atlantic coast are the Gulf Stream system flowing northward and the 

Labrador Current flowing southward. The Gulf Stream is the western boundary current of the North 

Atlantic Subtropical Gyre that strongly influences the physical oceanography of the MAB and SAB 

(Pickard and Emery, 1990; Verity et al., 1993). Offshore southeastern Florida, the Gulf Stream begins in 

the Florida Straits as the Florida Current, a continuation of the Loop Current from the Gulf of Mexico. 

The Florida Current is that section of the Gulf Stream that stretches from the Florida Straits north to Cape 

Hatteras, North Carolina. A composite of the Loop Current, Florida Current, and Gulf Stream positions 

from satellite imagery is shown in Figure F-6. 

Figure F-6. Loop Current (Gulf of Mexico) and Gulf Stream (Atlantic Coast) Locations Based on Trajectories of 

Near-surface Drifting Buoys from 1978-2003 (Cooperative Institute for Marine and Atmospheric 

Studies, 2008). 

The Gulf Stream is a powerful, warm, and swiftly flowing current that flows northward, generally 

along the shelf edge, carrying warm equatorial waters into the cooler North Atlantic (Pickard and Emery, 

1990; Verity et al., 1993). It generally follows the shelf edge up the southeast coast until it reaches 

Cape Hatteras, where it begins its northeastward flow across the Atlantic Ocean toward Europe (Pickard 

and Emery, 1990). The Antilles Current, which originates from the North Equatorial Current and flows 
Physical and Environmental Settings F-9

northwestward along the eastern edge of the Bahamas, contributes to the Gulf Stream when it joins the 

Florida Current off the east coast of Florida. 

About 30 million m3

/s (1,060 million ft3/s) of water is transported through the Florida Straits by the 

Florida Current; transport volume increases progressively to the northeast to about 85 million m3

/s 

(3,000 million ft3

/s) near Cape Hatteras (Pickard and Emery 1990). Surface current speed is high, at 

times exceeding 2.5 m/s (8.2 ft/s) with a mean surface velocity of about 1.8 m/s (5.9 ft/s) (Von Arx et al., 

1974; Tomczak and Godfrey, 2003). Current flow in the Florida Straits is greatest within about 200 m 

(656 ft) of the surface, with velocity decreasing with depth. Current speed is about 10 cm/s (0.3 ft/s) at 

depths greater than about 1,000 m (3,280 ft) (Tomczak and Godfrey, 2003). The Gulf Stream is typically 

80-150 km (50-93 mi) wide and 800-1,200 m (2,600-4,000 ft) deep and has a slightly lower flow rate 

after passing Cape Hatteras (80 million m3

/s [2.8 billion ft3/s]) where the velocity of the current also is 

fastest near the surface with a maximum speed of about 2.5 m/s (8 ft/s) (Pickard and Emery, 1990; 

Tomczak and Godfrey, 2003). 

In addition to the Gulf Stream, features such as rings, meanders, and filaments can form and affect 

shelf waters in the SAB (Science Applications International Corporation, 1984; Florida Institute of 

Oceanography, 1986). South of Cape Hatteras, meanders diverging from the Gulf Stream typically form 

frontal eddies that remain attached to the Gulf Stream. North of Cape Hatteras, meanders pinch off to 

form small gyre features that become separated from the Gulf Stream as either warm or cold core rings 

(Mann and Lazier, 1996). 

Off northeastern Florida, the Gulf Stream flows consistently northward. Although its position remains 

fairly stable off northeastern Florida, lateral meandering does occur (Bane et al., 1981; Lee et al., 1981; 

Dept. of the Navy, 1995). Frontal eddies, filaments, and warm and cold core rings may form during 

development of a meander and move across the shelf. Over the SAB shelf, there is a broad, slow, 

northerly flow with frequent intrusions of the Gulf Stream. Currents and water masses on the SAB shelf 

are mainly influenced by the Gulf Stream's deflections, meanders, and flow with mean current speeds on 

the shelf ranging from 1.8 m/sec (3.5 kn) near the surface to 0.40 m/sec (0.8 kn) near the bottom (Lee and 

Waddell, 1983). Surface velocities within the Gulf Stream offshore northeastern Florida are higher, 

ranging from 1.03 to 2.57 m/sec (2 to 5 kn) (Mann and Lazier, 1996) with a difference in current speeds 

reported for December (0.30 m/sec [0.6 kn]) and July (0.50 m/sec [1 kt]) (Dept. of the Navy, 1986). 

Anticyclonic meanders that pinch off from the Gulf Stream form a separated deep pool of warm 

Sargasso Sea water rotating clockwise known as warm core rings (Brooks, 1996). Warm core rings span 

100 km (~54 nmi) in diameter (García-Moliner and Yoder, 1994) with vertical dimensions of about 1 km 

(0.6 nmi) and may persist for several weeks to more than a year, drift in a south-to-southwesterly 

direction, and either dissipate or merge with the Gulf Stream (Pickard and Emery, 1990; Mann and 

Lazier, 1996; García-Moliner and Yoder, 1994); on average, 22 warm-core rings are formed per year, 

each measuring approximately 100 km (54 nmi) in diameter and 1,000 m (3,280 ft) in the vertical 

dimension (Gyory et al., 2005). When a cyclonic meander pinches off the Gulf Stream, cold core rings 

form, a counterclockwise rotating ring of cool continental slope water surrounded by the warmer waters 

of the Sargasso Sea (Pickard and Emery, 1990). Cold core rings form twice as frequently as warm core 

rings. On average, 35 cold-core rings are shed by the Gulf Stream per year (Gyory et al., 2005). Cold 

core rings are larger (100-300 km [54-162 nmi] in diameter) and last longer, persisting from months to 

years. Cold core rings form to the south of the Gulf Stream, drift in a south-to-southwest direction, and 

eventually dissipate or merge with the Gulf Stream in a similar fashion to their warm core ring 

counterparts (Pickard and Emery, 1990). Frontal eddies are distinct features from the larger cold and 

warm core rings that pinch off the Gulf Stream after it is deflected from the U.S. coastline. Frontal eddies 

often take the form of finger-like extensions and protrude onto the shelf, folding back to enclose a cold, 

nutrient-rich core of water upwelled from deep within the Gulf Stream (Mann and Lazier, 1996). The 

transient upwelling associated with frontal eddies results in more localized areas of high surface primary 

productivity. The formation of warm and cold core rings does not appear to be correlated with 

seasonality, but rather appears to be driven by localized flow dynamics of the Gulf Stream. 

Upwelling along the Atlantic coast is both wind-driven and a result of dynamic uplift (Shen et al., 

2000; Lentz et al., 2003). Upwelling can occur along the area of the MAB from New Jersey to Virginia 

during summer months when southwesterly winds prevail (Cook, 1988). In some areas of the upper 

MAB, upwelling occurs in stratified waters (spring and summer) after the passing of storms 

(Cook, 1988). 
F-10 Atlantic G&G Programmatic EIS 

In addition to the Gulf Stream, currents originating from the outflow of both Chesapeake and 

Delaware Bays influence the surface circulation in the MAB. The Chesapeake Bay plume flows seaward 

from the mouth of the Bay and then turns south to form a coastal jet that can extend as far as 

Cape Hatteras. Similarly, the Delaware Coastal Current begins in Delaware Bay and flows southward 

along the Delmarva Peninsula before being entrained into the Chesapeake Bay plume. 

3. WATER QUALITY 

This section provides a regional description of water quality in the AOI. Additional information on 

chemical oceanography and water quality is provided in a literature synthesis by Windom (2011). 

Water quality is typically gauged by measuring a series of parameters such as dissolved oxygen, 

transparency (i.e., water clarity, turbidity, or suspended matter), chlorophyll content, nutrient 

concentrations, and contaminant concentrations (heavy metals and hydrocarbons). Offshore water quality 

in the AOI is expected to be generally good to excellent, with low water column stratification, nitrogen 

and phosphorus concentrations, and chlorophyll concentrations. Additionally, observations of high water 

clarity, dissolved oxygen concentrations at or near saturation, and low concentrations of suspended matter 

and trace metal and hydrocarbon contaminants indicate good water quality (U.S. Environmental 

Protection Agency [USEPA], 1998). Concentrations of suspended matter (turbidity) are typically low in 

Mid-Atlantic marine waters, generally <1 mg/L (Louis Berger Group, Inc., 1999). Suspended matter and 

turbidity vary locally between surface and bottom waters, vary seasonally (because of rainfall and riverine 

discharge), are located in different areas because of differing sources and grain sizes, and increase 

naturally during storm events. Turbidity may be temporarily affected by dredging activities, in offshore 

waters this would be limited primarily to disposal at approved offshore disposal sites. These sites are 

located, designed, and operated under permit guidelines of the Clean Water Act (CWA) and the Marine 

Protection, Research, and Sanctuaries Act (MPRSA) to ensure any changes in turbidity would be 

localized and short-term (USEPA, 2011a). 

The overall condition of coastal waters is rated as fair. This assessment is based on an evaluation of 

five indices: water quality, sediment, benthic, coastal habitat, and fish tissue contaminants. The southeast 

coast is rated as fair with an index score of 3.6 while for the northeast coast is rated fair to poor with a 

score of 2.2 (based on a scale from 1 to 5) (USEPA, 2008). 

Some areas of the Atlantic have heavy shipping traffic and may experience localized impacts from 

ships, especially from bilge water, domestic wastewater, and tank washings. Ship discharges are 

regulated under USEPA’s National Pollution Discharge Elimination System (NPDES) vessels program. 

The primary means of regulation is the Vessel General Permit, which applies to discharges incidental to 

the normal operation of all non-recreational, non-military vessels of 79 feet or greater in length which 

discharge in waters of the U.S. (USEPA, 2011b). 

Pelagic tar is probably the most common form of hydrocarbon contamination present in the offshore 

environment (Farrington, 1987). Higher tar concentrations tend to be associated with the Loop Current 

and the Gulf Stream while only trace concentrations are found over the continental shelf. Van Vleet 

(1984) indicated that tanker operations may be the major source of pelagic tar. 

Hydrocarbon and metal concentrations in MAB and SAB sediments vary with sediment texture, but 

with the exception of disposal sites, are not indicative of significant contamination (Lee, 1979; Smith et 

al., 1979; Windom and Betzer, 1979). Metal and hydrocarbon concentrations on the continental slope 

tend to be higher than on the shelf because of the greater proportions of silt and clay in slope sediments. 

Trace metals include elements that are generally present in minute amounts in the sediment. With the 

exception of dump sites, trace metal concentrations nearshore and offshore rarely approach toxicity limits 

defined by the USEPA. To assist in understanding applicable limits, the National Oceanic and 

Atmospheric Administration (NOAA) has recently upgraded its Screening Quick Reference Tables 

(SQuiRTs) to include an expanded list of analytes for which benchmarks are presented (U.S. Dept. of 

Commerce [USDOC], NOAA, 2011). Elevated lead concentrations have been detected, decreasing with 

depth in the sediment column, suggesting an anthropogenic source (U.S. Dept. of the Interior [USDOI], 

Minerals Management Service [MMS], 1992). On the Mid-Atlantic slope and rise, sediment samples 

indicated that hydrocarbons found were either mainly biogenic in origin or were contaminants derived 

from the burning of fossil fuels. Biogenic gas is found in all marine sediments, but no evidence of 
Physical and Environmental Settings F-11

petroleum contamination was reported in sediments from the South Atlantic slope and rise (USDOI, 

MMS, 1992). 

In coastal waters, water quality is controlled primarily by the anthropogenic inputs of land runoff, 

land point source discharges, and atmospheric deposition. With increasing distance from shore, oceanic 

circulation patterns play an increasingly larger role in dispersing and diluting anthropogenic contaminants 

and determining water quality. Due primarily to the influence of tidal plumes leaving estuaries, areas of 

the Atlantic closer to shore will show major local variations (USDOI, MMS, 1992). While the overall 

quality of U.S. coastal waters has been rated fair in all three National Coastal Condition Reports issued by 

USEPA, the overall condition of U.S. coastal waters has improved slightly since the 1990s 

(USEPA, 2008). 

Most threats to marine water quality originate on land. Immediately along the coastline water quality 

is influenced by cities and other large nearby populations with associated non-point pollution sources: 

urban runoff containing oil, greases, and nutrients; domestic and sanitary wastes; and large expanses of 

agricultural land where fertilizers and biocides are applied. In less populated areas networks of wetlands, 

estuaries, and bays can be subject to effluents from distributed septic systems. Plumes from the two 

prominent estuaries in the MAB, Chesapeake and Delaware Bays, affect coastal water quality. These 

estuaries have extensive watersheds that funnel nutrients, sediment, and organic material into secluded, 

poorly flushed estuaries that are much more susceptible to eutrophication, the pattern of which also 

closely reflects the distribution of population density (USEPA, 2008). Hypoxia, the condition of having 

low dissolved oxygen concentration in the water, is caused by excessive nutrients and other 

oxygen-demanding contaminants. Hypoxia often forms when the water column becomes vertically 

stratified, and mixing between oxygenated surface waters and bottom waters cannot occur. Hypoxia is 

not a widespread phenomenon in the AOI. However, it does occur, most notably during the summer in 

the deeper waters of Chesapeake Bay (Hagy et al., 2004). 

Between 1980 and 2003, coastal counties of the Southeast Coast region showed the largest rate of 

population increase (58 percent) of any coastal region in the conterminous U.S. In 2003, the coastal 

population of the Northeast Coast region was the largest in the country, with 52.6 million people, 

representing 34 percent of the nation’s total coastal population. Although coastal counties along the 

Northeast Coast showed the slowest rate of population increase between 1980 and 2003, the region gained 

the second-largest number of people (almost 8 million) of all U.S. regions during this period 

(USEPA, 2008). 

4. METEOROLOGY AND AIR QUALITY 

Oceanographic and atmospheric phenomena combine to create the long-term climate and short-term 

weather patterns that characterize the AOI. The regional climate is influenced by several factors, 

including oscillating atmospheric pressure systems, prevailing winds, and warm Gulf Stream waters. 

Three atmospheric pressure systems govern the wind patterns and climate in this region: the Icelandic 

Low, the Bermuda-Azores High, and the Ohio Valley High (Blanton et al., 1985). The Bermuda-Azores 

High is a semi-permanent, high-pressure system centered over the island of Bermuda in summer and fall 

and over the Azores in the eastern North Atlantic in winter and spring. The anticyclonic (clockwise) 

circulation associated with the Bermuda-Azores High dominates the climate from approximately May 

through August, producing southeasterly winds (<6 m/s [<20 ft/s]) and hot, humid weather over much of 

the southeastern U.S. In winter (approximately November through March), the Icelandic Low and weak 

Ohio Valley High combine to generate west-northwesterly winds (8-10 m/s [26-33 ft/s]) and drier weather 

conditions in the region (Adams et al., 1993). Wind velocities offshore of Cape Canaveral exhibited 

similar trends, but with slightly lower average speeds at 4.6 m/s (15.1 ft/s) in summer and 6.7 m/s (22 ft/s) 

in winter (USDOC, NOAA, National Data Buoy Center [NDBC], 2011a). Weather systems pass rapidly 

through the southeastern U.S. (approximately every 2-5 days) throughout the year, and their effects are 

superimposed on the seasonal cycling of the Bermuda-Azores High (Joyce, 1987). While there is a large 

range of changes in air temperature, wind, and barometric pressure between seasons, fluctuations 

associated with the passage of weather systems may exceed seasonal changes. 

A long-term record of atmospheric and oceanographic conditions is available from oceanographic 

buoys maintained by the USDOC, NOAA, NDBC (2011b). Air temperature measured over a 17-year 

period at an oceanographic buoy 48 km (26 nmi) southeast of Cape May, New Jersey, averaged 23.3 °C 
F-12 Atlantic G&G Programmatic EIS 

(73.9 °F) in August and 3.6 °C (38.5 °F) in February, the warmest and coldest months, respectively 

(USDOC, NOAA, NDBC, 2011c). In contrast, a buoy located 278 km (150 nmi) east of Cape Hatteras 

recorded mean monthly air temperatures of 26.1 °C (79.0 °F) in August and 14.9 °C (58.8 °F) in January 

over a concurrent 25-year period (USDOC, NOAA, NDBC, 2011d), illustrating the warming influence of 

the Gulf Stream. 

Prevailing westerly winds result in a tropical/subtropical climate south of Cape Hatteras 

(Joyce, 1987). Air temperature measured in southeast Onslow Bay averages 26 °C (78.8 °F) in summer 

(June through August) and 13 °C (55.4 °F) in winter (December through February), with annual extremes 

of 31 °C (87.8 °F) and -12 °C (10.4 °F) (Coastal Ocean Research and Monitoring Program, 2011). By 

contrast, air temperatures recorded from a NOAA oceanographic buoy located approximately 37 km 

(20 nmi) off Cape Canaveral averaged 27.1 °C (80.8 °F) in summer and 19.8 °C (67.6 °F) in winter 

between 1988 and 2001 (USDOC, NOAA, NDBC, 2011a). Warmer average temperatures and 

temperature extremes of 31.8 °C (89.2 °F) and 0 °C (32.0 °F) are almost certainly a result of the 

moderating influence of the warm Gulf Stream waters. 

Over the past 50 years, total annual precipitation has averaged about 115 cm (45 in) in Lewes, 

Delaware and 145 cm (57 in) at Cape Hatteras, North Carolina (Southeast Regional Climate Center, 

2011a,b). Precipitation in the form of snow or freezing rain occurs more frequently in the north. Average 

annual precipitation ranges between 109 and 142 cm (43 and 56 in) along the coastlines of the Carolinas, 

Georgia, and northern Florida (Boyles et al., 2004). Maximum rainfall occurs in late summer; however, 

maximum discharge of freshwater from local rivers into the SAB occurs in March or April as water drains 

from inland mountain and piedmont areas, which receive their maximum rainfall in the early spring 

(Blanton et al., 1985). 

The proximity of the Gulf Stream to the southeast U.S. coast has a strong effect in the generation of 

cyclonic, extra-tropical storms in winter as cold, dry continental air meets the warm, moist air over Gulf 

Stream waters (Adams et al., 1993). Thunderstorms and major storm systems occur in the region most 

often during summer and fall as hot, humid air masses collide with passing fronts (Joyce, 1987). 

Tropical and extra-tropical cyclones are significant influences on weather and sea state conditions in 

the AOI. Tropical cyclones, which occur during summer and fall, are severe but infrequent. 

Extra-tropical cyclones occur frequently during winter and may produce unfavorable conditions during 

winter and spring. Most major storms, including hurricanes, occur during the North Atlantic hurricane 

season, which occurs from June through November. Tropical cyclones form in warm, equatorial waters 

of the North Atlantic Ocean and Caribbean Sea and often move northward along the southeastern 

U.S. coast following the path of the Gulf Stream (Adams et al., 1993; Buchan, 2000). Since 1944, when 

reliable data on storm systems began being recorded, 655 named storms have occurred over the North 

Atlantic; 162 of these storms were major hurricanes (USDOC, NOAA, National Climatic Data Center 

[NCDC], 2011a). From 1950 through 2005, 27 hurricanes made first landfall between Cape Canaveral, 

Florida and Cape Hatteras, with just two hurricanes striking the coast between Cape Hatteras and Long 

Island, New York (USDOC, NOAA, NCDC, 2011b). 

Air quality typically is defined by the concentration of criteria pollutants established by USEPA 

under the National Ambient Air Quality Standards (NAAQS)—a listing that identifies those pollutants 

considered harmful to public health and the environment. The Clean Air Act (CAA) establishes two 

types of national air quality standards: (1) primary standards, which set limits to protect public health, 

including the health of "sensitive" populations (e.g., asthmatics, children, and the elderly); and 

(2) secondary standards, which set limits to protect public welfare, including protection against decreased 

visibility and damage to animals, crops, vegetation, and buildings. The NAAQS have been established 

for six principal pollutants (called “criteria” pollutants): carbon monoxide, lead, nitrogen dioxide, ozone, 

particulate matter (PM10 and PM2.5), and sulfur oxides. 

Outer continental shelf (OCS) waters are not classified as to the presence of criteria pollutants under 

NAAQS and the CAA. Ambient air quality offshore is expected to range from good to excellent because 

of the distance from significant emission sources (e.g., large urban areas or concentrated offshore 

development). Most of the coastal counties adjacent to the AOI have all criteria pollutants present. 

However, Sussex County, Delaware at the mouth of Delaware Bay is part of the 

Philadelphia-Wilmington-Atlantic City moderate nonattainment area for 8-h ozone. The 

Norfolk-Virginia Beach-Newport News-Hampton Roads area in Virginia is a maintenance area for 8-h 

ozone. A maintenance area is an area that has been redesignated to attainment for the 8-hour ozone 
Physical and Environmental Settings F-13

standard. There are no other coastal nonattainment or maintenance areas adjacent to the AOI (USEPA, 

2011c). 

5. ACOUSTIC ENVIRONMENT 

Various activities and processes, both natural and anthropogenic, combine to form the sound profile 

within the ocean, generally referred to as ambient ocean noise (Richardson et al., 1995). Most ambient 

noise is broadband (composed of a spectrum of numerous frequencies without a differentiating pitch) and 

encompasses virtually the entire frequency spectrum. Vessel traffic is a major contributor to ocean noise 

between 5 and 500 Hz (National Research Council [NRC], 2003). Spray and bubbles associated with 

breaking waves are the major contributions to ambient noise in the 500-to-100,000-Hz range. At 

frequencies greater than 100,000 Hz, “thermal noise” caused by the random motion of water molecules is 

the primary source. Ambient noise sources, especially noise from wave and tidal action, can cause 

coastal environments to have particularly high ambient noise levels. 

A large portion of the noise from vessel traffic comes from vessel engines and propellers, and those 

sounds occupy the low frequencies used by most large whales (Richardson et al., 1995). In the open 

water, ship traffic can influence ambient background noise at distances of thousands of kilometers; 

however, the effects of ship traffic sounds in shallow coastal waters are much less far reaching, most 

likely because a large portion of the sound’s intensity is absorbed by soft, nonreflective, unconsolidated 

materials (sands and mud) on the seafloor. Other anthropogenic sources include dredging, nearshore 

construction activities, and sonar signals (especially those used by the military). Offshore oil and gas 

operations contribute to the ambient noise in other regions, but are not currently occurring in the AOI. 

Long-term data analyzed by McDonald et al. (2006) offshore California show an increase in ambient 

noise of approximately 10-12 dB in the frequency range 30-50 Hz over a 40-year period, suggesting an 

average noise increase rate of 2.5-3 dB per decade. The authors attributed the change to increased levels 

of shipping traffic. While comparable long-term data for the AOI have not been published, it is assumed 

that underwater noise from vessel traffic and other anthropogenic sources is increasing and will continue 

to increase incrementally over the next decade. 

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Information Resources: Data Search and Literature Synthesis. U.S. Dept. of the Interior, Bureau of 

Ocean Energy Management, Regulation, and Enforcement, Gulf of Mexico OCS Region, New 

Orleans, LA. OCS Study BOEMRE 2011-xxx. 

Windom, H.L and P.R. Betzer. 1979. Chapter 4: Trace metal chemistry of South Atlantic/Georgia Bight. 

In: Texas Instruments, Inc., South Atlantic Benchmark Program, Outer Continental Shelf (OCS) 

Environmental Studies. Volume 3. Results of studies of Georgia Bight of North Atlantic Ocean. 

Prepared for Bureau of Land Management. Contract No. AA551-CT7-2. Available at: http://

www.gomr.boemre.gov/PI/PDFImages/ESPIS/4/4453.pdf. Accessed August 19, 2011. 
APPENDIX G 

 

RECENT PUBLICATIONS OF THE 

ENVIRONMENTAL STUDIES PROGRAM, ATLANTIC REGION,

2006 TO PRESENT

Recent Publications of the Environmental Studies Program, Atlantic Region G-3

The Bureau of Ocean Energy Management (BOEM) funds ocean research through the Environmental 

Studies Program to provide science in support of management decisions. This Appendix lists 

Environmental Studies Program publications issued from 2006-2011 that are relevant to the Atlantic 

Outer Continental Shelf (OCS). Older Atlantic OCS publications are listed on the BOEM website 

(U.S. Dept. of the Interior [USDOI], BOEM, 2011a), and most Environmental Studies Program 

publications are available online through the Environmental Studies Program Information System 

(ESPIS) (USDOI, BOEM, 2011b). 

Study Number Title 

2011 

BOEMRE 2011-037 

Commercial Wind Lease Issuance and Site Characterization Activities on the Atlantic 

Outer Continental Shelf Offshore New Jersey, Delaware, Maryland, and Virginia 

http://www.boemre.gov/offshore/renewableenergy/PDFs/

MidAtlanticWEAs_DraftEA.pdf

BOEMRE 2011-019 A Comparison of Marine Productivity Among Outer Continental Shelf Planning Areas 

http://www.gomr.boemre.gov/PI/PDFImages/ESPIS/5/5121.pdf

2010

BOEMRE TA&R 648 

Offshore Wind Energy Installation and Decommissioning Cost Estimation in the 

U.S. Outer Continental Shelf 

http://www.boemre.gov/tarprojects/648/aa.pdf

2009

MMS 2009-020 Determining Night-time Distribution of Long-tailed Ducks Using Satellite Telemetry 

http://www.gomr.boemre.gov/PI/PDFImages/ESPIS/4/4823.pdf

MMS 2009-011 

Workshop on Environmental Research Needs in Support of Potential Virginia Offshore 

Oil and Gas Activities 

http://www.gomr.boemre.gov/PI/PDFImages/ESPIS/4/4723.pdf

2008 

MMS 2008-060 

Final Biological Characterization and Numerical Wave Model Analysis within Borrow 

Sites Offshore of Florida’s Northeast Coast Report Volume I 

No. 1435-01-05-CT-39075-M05PC00005 

http://www.boemre.gov/sandandgravel/PDF/2008-060_Volume1.pdf

2007

MMS 2007-057 Workshop to Identify Alternative Energy Environmental Information Needs 

http://www.gomr.boemre.gov/PI/PDFImages/ESPIS/4/4291.pdf

MMS 2007-048 

Examination of the Physical and Biological Implications of Using Buried Channel 

Deposits and Other Non-topographic Offshore Features as Beach Nourishment Material

http://www.gomr.boemre.gov/PI/PDFImages/ESPIS/4/4274.pdf

MMS-2007-038 

Worldwide Synthesis and Analysis of Existing Information Regarding Environmental 

Effects of Alternative Evergy Uses on the Outer Continental Shelf 

http://www.boemre.gov/itd/pubs/2007/2007-038.pdf

MMS 2007-033 Cooperative Research to Study Dive Patterns of Sperm Whales in the Atlantic Ocean 

http://www.gomr.boemre.gov/PI/PDFImages/ESPIS/4/4247.pdf

2006

MMS 2006-065 

Investigation of Dredging Impacts on Commercial and Recreational Fisheries and 

Analysis of Available Mitigation Measures to Protect and Preserve Resources 

http://www.boemre.gov/sandandgravel/PDF/FloridaStudyReport/Studies/2006-065.pdf

REFERENCES CITED

U.S. Dept. of the Interior, Bureau of Ocean Energy Management. 2011a. Available at: http://

www.gomr.boemre.gov/homepg/whatsnew/publicat/atlantic/atlantic.html. Accessed November 29, 

2011. 

U.S. Dept. of the Interior, Bureau of Ocean Energy Management. 2011b. Environmental Studies 

Program Information System. Available at: https://www.gomr.boemre.gov/homepg/espis/

espisfront.asp. Accessed November 29, 2011. 

APPENDIX H 

 

MARINE MAMMAL HEARING AND

SENSITIVITY TO ACOUSTIC IMPACTS

Marine Mammal Hearing and Sensitivity to Acoustic Impacts H-iii 

TABLE OF CONTENTS 

Page 

1. INTRODUCTION/OVERVIEW ......................................................................................................H-1

2. ROLE OF ACOUSTICS IN MARINE MAMMAL ECOLOGY .....................................................H-1

3. HEARING IN MARINE MAMMALS.............................................................................................H-3

3.1. Hearing in Mysticete Cetaceans..............................................................................................H-4

3.2. Hearing in Odontocete Cetaceans ...........................................................................................H-4

3.3. Hearing in Pinnipeds and Manatees........................................................................................H-5

3.4. Marine Mammal Hearing Weighting Functions .....................................................................H-5

4. EFFECTS OF NOISE ON MARINE MAMMAL HEARING AND BEHAVIOR..........................H-7

4.1. Effects of Noise on Marine Mammal Physiology...................................................................H-7

4.2. Effects of Noise on Marine Mammal Hearing........................................................................H-7

4.2.1. Temporary and Permanent Threshold Shift in Marine Mammals...............................H-8

4.2.2. Auditory Masking .......................................................................................................H-9

4.3. Effects of Noise on Marine Mammal Behavior ....................................................................H-10

5. MARINE MAMMAL NOISE EXPOSURE CRITERIA ...............................................................H-10

6. ASSESSMENT OF HEARING INFORMATION FOR SPECIES/GROUPS IN THE AREA 

OF INTEREST................................................................................................................................H-15

7. REFERENCES CITED...................................................................................................................H-16

Marine Mammal Hearing and Sensitivity to Acoustic Impacts H-v 

LIST OF FIGURES 

Page 

Figure H-1. Frequency Range of Sounds Generally Produced by Different Marine Animal 

Groups Shown Relative to Major Human Noise Sources...................................................H-2

Figure H-2. Typical Hearing Curve or “Audiogram” Obtained from a California Sea Lion with a 

Behavioral Testing Technique ............................................................................................H-3

Figure H-3. Measured or Estimated Functional Hearing Ranges for Different Marine Vertebrate 

Groups Shown Relative to Various Human Noise Sources ................................................H-4

Figure H-4. Frequency-weighting Functions for Cetaceans and Pinnipeds in Air and Water 

Proposed by Southall et al. (2007) ......................................................................................H-6

Figure H-5. Time Series Plot Showing a Calling Blue Whale and the Increasing Noise (and 

Masking) in the Same Low-Frequency Band from an Approaching Vessel.......................H-9

Marine Mammal Hearing and Sensitivity to Acoustic Impacts H-vii 

LIST OF TABLES 

Page 

Table H-1. Marine Mammal Functional Hearing Groups and Estimated Functional Hearing 

Ranges Proposed by Southall et al. (2007) .........................................................................H-6

Table H-2. Sound Source Categories, Acoustic Characteristics, and Examples, as Proposed by 

Southall et al. (2007).........................................................................................................H-11

Table H-3. Marine Mammal Noise Exposure Criteria for Injury for Different Marine Mammal 

Functional Hearing Groups Proposed by Southall et al. (2007) .......................................H-12

Table H-4. Marine Mammal Noise Exposure Criteria for Behavior for Different Marine 

Mammal Functional Hearing Groups Proposed by Southall et al. (2007) ........................H-13

Table H-5. Southall et al. (2007) Assessment of Individual Behavioral Responses of 

Low-Frequency Cetaceans to Multiple-Pulse Exposure for Various Received Levels ....H-14

Marine Mammal Hearing and Sensitivity to Acoustic Impacts H-1 

1. INTRODUCTION/OVERVIEW 

Marine animals critically depend on sound to live, making and listening to it in various ways to 

perform various life functions. The ocean is a naturally noisy place, but humans make a host of sounds 

that are increasingly impinging on the ocean acoustic environment. There is clear evidence that some of 

these sounds can negatively impact marine life, but the types and magnitudes of impacts as they relate to 

different species and sound types remain poorly understood in all but a few conditions. However, there 

has been significant progress in the last decade, particularly in scientific knowledge in these areas, for 

some species and conditions, both in terms of hearing impacts and behavioral responses to various kinds 

of noise. From this evolution in understanding has emerged new ways of assessing and mitigating 

potential impacts. While much of the focus and discussion have been on potential injurious types of 

sound impacts (driven by concerns over hearing/tissue damage and the isolated mass strandings of beaked 

whales exposed to military sonar), more focus recently has been on the impacts of human noise on 

biologically significant behaviors and the overall acoustic ecology of marine life. There is a realization 

that the footprints within which direct harm may occur are relatively small, and the conditions in which 

marine mammals will become stranded appear to be restricted. However, the areas over which animals 

may be disturbed in significant ways that may impact vital life functions can be significantly larger. 

These considerations and the underlying complexity of understanding and assessing their probability of 

occurrence, as well as mitigation, have become more critical in noise exposure criteria and other means of 

assessment. Many of these issues and the underlying science are considered in detail in a major 

comprehensive review and application of science in the context of noise exposure criteria (Southall et al., 

2007). That assessment forms the current basis for much of this appendix, but subsequent studies have 

provided additional important findings that are also summarized here. 

This appendix summarizes the current state of scientific knowledge about the importance of sound 

and effects of noise on marine animals, with particular attention to marine mammals. It considers 

separately the effects of noise on physiology, hearing, communication, and behavior from a range of 

different impulsive and continuous sound sources. It also considers historical and emerging noise 

exposure criteria and operational mitigation measures, with attention to the types of acoustic sources 

present in the proposed geological and geophysical (G&G) operations off the U.S. East Coast. Finally, 

noise impacts for endangered/threatened species most likely to be present in these areas are considered. 

2. ROLE OF ACOUSTICS IN MARINE MAMMAL ECOLOGY 

The underwater acoustic environment can be a noisy place, receiving sound from a host of natural and 

anthropogenic sources. Some natural sounds are biological (e.g., fishes, marine mammals, some 

invertebrates), and others are environmental (e.g., waves, earthquakes, rain). Among the anthropogenic 

sources, many produce noise as a by-product of their normal operations (e.g., shipping, drilling, tidal 

turbines), whereas others (e.g., sonars, airguns) are produced for a specific remote sensing purpose 

(see Hildebrand [2009] for a recent review). Detailed measurements have been made for many of these 

sources, but their degree of overlap with and impacts on acoustically-oriented marine life remains 

generally poorly understood. 

For most marine vertebrates, the production and reception of sound serves critical biological 

functions, including communication, foraging, navigation, and predator-avoidance (e.g., Schusterman, 

1981; Watkins and Wartzok, 1985; Richardson et al., 1995; Tyack, 1998; Wartzok and Ketten, 1999; 

National Research Council [NRC], 2003; 2005; Clark and Ellison, 2004; Southall et al., 2007). As a 

general statement, all studied marine mammals produce sounds in a variety of inter- and intra-individual 

contexts, most associated with vital life functions as identified by the NRC (2005). As described below 

and shown in Figure H-1 in comparison with some of the major human noise sources, each species group 

utilizes different frequency ranges. 
H-2 Atlantic G&G Programmatic EIS

Figure H-1. Frequency Range of Sounds Generally Produced by Different Marine Animal 

Groups Shown Relative to Major Human Noise Sources. 

Dolphins, porpoises, and other toothed whales (odontocete cetaceans) have developed sophisticated 

biosonar capabilities involving high frequency impulsive clicks to feed and navigate (Au, 1993) and use a 

variety of whistles and other calls to communicate in social interactions. These animals make sounds 

across some of the widest frequency bands that have been measured in any animal group. 

Communicative sounds generally range from a few hundreds of hertz to several tens of kilohertz, but 

echolocation clicks can extend above 100 kHz. 

Baleen whales (mysticete cetaceans) have developed moderate to long-range communication 

capabilities for reproductive and social interactions and to orient themselves in the underwater world 

(e.g., Clark, 1990; Popper and Edds-Walton, 1997). Large whales generally produce low-frequency 

sounds in the tens of hertz to the several kilohertz band, with a few signals extending above 10 kHz. 

Other marine mammals such as pinnipeds, manatees, and polar bears make and listen to sounds for a 

variety of communicative and spatial orientation functions, but like the large whales they appear to lack 

specialized echolocation capabilities (Schusterman, 1981; Schusterman et al., 2000). These sounds can 

extend above those used by mysticetes but occur over a narrower frequency band than those used by 

odontocetes, generally from ~100 Hz to several tens of kilohertz. Pinnipeds and polar bears spend time 

both at sea and on land, however, and thus rely on sounds both above and below the water. 

Finally, many fishes make and listen to sounds in mating and other social interactions (Kaatz, 2002). 

Most of these sounds are generally low-frequency in nature, although some fishes produce more 

impulsive sounds as well. Aside from some simple hissing and other sounds produced in air, marine 

turtles generally do not appear to produce sounds in water for communicative or foraging purposes, but 

may rely on sound in a general orienting sense. 
Marine Mammal Hearing and Sensitivity to Acoustic Impacts H-3 

3. HEARING IN MARINE MAMMALS 

Hearing has been measured using behavioral and/or electrophysiological methods in about a quarter 

of the known marine mammal species, although with a disproportional representation of species 

commonly found in captivity, and some entire groups (e.g., mysticete cetaceans) remain untested. For a 

detailed review, see Southall et al. (2007); key findings obtained since then are discussed below. Hearing 

sensitivity is generally quantified by determining the quietest possible sound that is detectable by an 

animal (either via a behavioral response or by quantifying an electrical response) on some signal 

presentations. By testing such responses across a range of test frequencies, a measure of the animal’s 

overall hearing capability (typically called an “audiogram”) may be obtained; an example is given in 

Figure H-2. 

Figure H-2. Typical Hearing Curve or “Audiogram” Obtained from a California Sea 

Lion with a Behavioral Testing Technique. 

Where detection threshold levels are lower, hearing sensitivity is greater (the animal can hear well), 

and vice versa. This sensitivity usually follows a U-shaped curve with regions of relatively good 

sensitivity that drop off on the low and high ends. The region of lowest overall average hearing is called 

the range of “best hearing sensitivity.” Similarly, the region where hearing thresholds are within some 

range from the lowest overall threshold (e.g., 80 dB in Southall et al., 2007) is often referred to as the 

overall range of functional hearing. 

Given the available direct measurements of hearing, extrapolations based on taxonomy, and 

predictions based on auditory morphology, vocalizations, or behavior, it is clear that not all marine taxa 

have equal hearing frequency ranges or absolute hearing sensitivity (Richardson et al., 1995; Wartzok and 

Ketten, 1999; Southall et al., 2007). 

As shown in Figure H-3, most marine taxa have measured or estimated (in the case of baleen whales) 

functional hearing capabilities across similar frequencies to those where their vocalizations occur, 

although perception may be slightly broader than the frequency range of vocalizations (Luther and Wiley, 

2009). Fishes generally hear in a relatively narrow frequency band up to just a few kilohertz, while 

marine mammals as a whole cover a very wide band, with baleen whales likely hearing down into very 
H-4 Atlantic G&G Programmatic EIS

low frequencies, pinnipeds at low to intermediate frequencies (relatively), and odontocete cetaceans 

hearing over a very broad range extending well into the ultrasonic (for humans) range. Recently, 

functional hearing has been demonstrated in a marine invertebrate as well (longfin squid; see 

Mooney et al., 2010). Specific hearing characteristics for different marine mammal groups are described 

below. 

Figure H-3. Measured or Estimated Functional Hearing Ranges for Different Marine Vertebrate 

Groups Shown Relative to Various Human Noise Sources. 

3.1. HEARING IN MYSTICETE CETACEANS

Because of the lack of captive subjects and logistical challenges of bringing experimental subjects 

into the laboratory, direct measurements of mysticete hearing are unavailable, although there was an 

unsuccessful attempt to directly measure hearing in a stranded gray whale calf by Ridgway and Carder 

(2001). Consequently, hearing in mysticetes is estimated based on other means such as vocalizations 

(Wartzok and Ketten, 1999), anatomy (Houser et al., 2001; Parks et al., 2007), behavioral responses to 

sound (Frankel, 2005; Reichmuth, 2007), and nominal natural background noise conditions in the likely 

frequency ranges of hearing (Clark and Ellison, 2004). 

The combined information from these and other sources strongly suggests that mysticetes are likely 

most sensitive to sound from perhaps tens of hertz to ~10 kHz. However, humpback whales (Megaptera 

novaeangliae) produce sounds with harmonics extending above 24 kHz (Au et al., 2006), and Ketten et al. 

(2007) suggested, based on anatomical data, that some mysticetes could hear frequencies up to 30 kHz. 

Southall et al. (2007) estimated the lower and upper frequencies for functional hearing in mysticetes, 

collectively, to be 7 Hz and 22 kHz, respectively, but based on the above information this may be a slight 

underestimate on the high frequency cutoff. Nevertheless, there appears to be little doubt that mysticetes 

operate primarily in the very low and low frequency ranges. 

3.2. HEARING IN ODONTOCETE CETACEANS

Because of the presence of specialized, high frequency biosonar and lower frequency communication 

systems in odontocete cetaceans, it is almost certain that they hear over an extremely wide frequency 

range, spanning some 12 octaves in some species. Hearing has been directly measured in controlled 

conditions for over a dozen odontocete species with either behavioral or electrophysiological techniques. 

Southall et al. (2007) reviewed the available literature and (like Wartzok and Ketten [1999]) identified 

two functional hearing groups within the odontocetes, which they referred to as mid-frequency cetaceans 
Marine Mammal Hearing and Sensitivity to Acoustic Impacts H-5 

(with functional hearing between 150 Hz and 160 kHz) and high-frequency specialists (functional hearing 

estimated between 200 Hz and 180 kHz). Subsequent to the Southall et al. (2007) publication, additional 

data have been obtained on several species that had been previously tested (such as harbor porpoise) and 

measurements or anatomical modeling results have been obtained for several new species – e.g., Cuvier’s 

beaked whales (Cranford et al., 2008a,b) and false killer whales (Montie et al., 2011) suggesting that 

these additional species have similar basic hearing ranges and functional capabilities to other cetaceans. 

These and other studies have contributed to an increased understanding of hearing in odontocete 

cetaceans, but they are fundamentally consistent for these species with the Southall et al. (2007) 

assessment for these species in terms of the broad range and high-frequency extension of functional 

hearing in odontocete cetaceans. 

3.3. HEARING IN PINNIPEDS AND MANATEES

Pinnipeds are amphibious mammals and have functional hearing both above and below the water, 

although they have broader functional hearing ranges in water (Kastak and Schusterman, 1998 for a 

discussion). Direct measurements of hearing using behavioral and electrophysiological methods have 

been obtained in nearly 10 different species (Southall et al., 2007; Mulsow and Reichmuth, 2010). 

Southall et al. (2007) estimated functional hearing across all pinnipeds as extending between 75 Hz and 

75 kHz under water and between 75 Hz and 30 kHz in air. However, they also noted that, as in the 

odontocete cetaceans, there appears to be a segregation in functional hearing within pinniped taxa, with 

phocids (seals lacking external ear pinnae that are less mobile on land, such as harbor seals) extending to 

much higher frequencies, especially in water, than otariids (seal lions and fur seals that have distinct 

external ear pinnae and are more agile on land). This would be a logical additional segregation in terms 

of functional hearing within marine mammals. 

Hearing has also been tested both in terms of absolute and masked hearing capabilities in manatees 

(Gerstein et al., 1999; Mann et al., 2005). The combined data suggest that manatees have hearing 

capabilities that are generally similar to phocid pinnipeds except perhaps at the lowest frequencies, with 

functional hearing between about 250 Hz and ~80 kHz. Based on these data, the extrapolation of 

pinniped data to manatees, where information is lacking, would seem reasonable. 

3.4. MARINE MAMMAL HEARING WEIGHTING FUNCTIONS

Because animals including marine mammals do not hear equally well at all frequencies, 

frequency-weighting functions are often used as a means of quantitatively compensating for differential 

frequency responses for different species. These are commonly applied in assessing the potential for the 

detection of a sound at a specific frequency and, more commonly, for assessing potential noise impacts. 

Noise exposure criteria are discussed in greater detail in Section 4.0. However, as they are related to the 

above generalizations regarding basic hearing in different marine mammal groups, the frequency 

weighting functions derived by Southall et al. (2007) are described briefly here. 

Table H-1 shows the five functional hearing groups and estimated functional hearing ranges for 

marine mammals proposed in the Southall et al. (2007) noise exposure criteria. 

Using the estimated lower and upper frequency cut-off limits as 6-dB down points on an exponential 

roll-off for the frequency-weighting functions (as is done in human C-weighting), Southall et al. (2007) 

developed frequency-weighting filters for each of the five functional hearing groups as shown in 

Figure H-4. 
H-6 Atlantic G&G Programmatic EIS

Table H-1 

 

Marine Mammal Functional Hearing Groups and Estimated Functional Hearing Ranges 

Proposed by Southall et al. (2007) 

Functional Hearing 

Group 

Estimated Auditory 

Bandwidth 

Genera Represented 

(Number Species/Subspecies) 

Frequency-Weighting

Network 

Low-frequency cetaceans 7 Hz to 22 kHz 

Balaena, Caperea, Eschrichtius, 

Megaptera, Balaenoptera

(13 species/subspecies) 

Mlf

(lf: low-frequency 

cetaceans) 

Mid-frequency cetaceans 150 Hz to 160 kHz

Steno, Sousa, Sotalia, Tursiops, Stenella, 

Delphinus, Lagenodelphis, 

Lagenorhynchus, Lissodelphis, Grampus, 

Peponocephala, Feresa, Pseudorca, 

Orcinus, Globicephala, Orcacella, 

Physeter, Delphinapterus, Monodon, 

Ziphius, Berardius, Tasmacetus, 

Hyperoodon, Mesoplodon

(57 species/subspecies) 

Mmf

(mf: mid-frequency 

cetaceans) 

High-frequency cetaceans 200 Hz to 180 kHz

Phocoena, Neophocaena, Phocoenoides, 

Platanista, Inia, Kogia, Lipotes, 

Pontoporia, Cephalorhynchus

(19 species/subspecies) 

Mhf

(hf: high-frequency 

cetaceans) 

Pinnipeds in water 75 Hz to 75 kHz 

Arctocephalus, Callorhinus, Zalophus, 

Eumetopias, Neophoca, Phocarctos, 

Otaria, Erignathus, Phoca, Pusa, 

Halichoerus, Histriophoca, Pagophilus, 

Cystophora, Monachus, Mirounga, 

Leptonychotes, Ommatophoca, Lobodon, 

Hydrurga, Odobenus

(41 species/subspecies) 

Mpw

(pw: pinnipeds in 

water) 

Pinnipeds in air 75 Hz to 30 kHz Same species as pinnipeds in water 

(41 species/subspecies) 

Mpa

(pa: pinnipeds in air)

Figure H-4. Frequency-Weighting Functions for Cetaceans (left) and Pinnipeds in Air and Water (right) 

Proposed by Southall et al. (2007). 
Marine Mammal Hearing and Sensitivity to Acoustic Impacts H-7 

4. EFFECTS OF NOISE ON MARINE MAMMAL HEARING AND 

BEHAVIOR 

Where there is an overlap between noise sources and the frequencies of sound used by marine life, 

there may be concerns related to how such sound may interfere with important biological functions. 

Noise, either natural or anthropogenic, can adversely affect marine life in various ways, inducing 

alteration of behavior, reduction of communication ranges or orientation capability, temporary or 

permanent damage to the auditory or other systems; and/or, in extreme cases, habitat avoidance or even 

death (e.g., Richardson et al., 1995; NRC, 2003, 2005; Nowacek et al., 2007; Southall et al., 2007). Noise 

impacts may also be additive or synergistic to those of other human stressors. While determining the 

biological significance of noise exposure impacts remains challenging (NRC, 2005), significant strides 

have been made in quantifying the effects of noise on marine mammals. The potential and measured 

effects of noise on physiology, hearing, and behavior are reviewed here, with attention to findings 

subsequent to the Southall et al. (2007) review and assessment of noise impacts on marine mammals. 

4.1. EFFECTS OF NOISE ON MARINE MAMMAL PHYSIOLOGY

Noise can result in direct, physiological impacts on marine mammals, even in cases where hearing 

impacts or even behavioral responses may be lacking. These may include stress responses and direct 

physical injury (e.g., tissue damage). Stress responses can vary from an acute startle response to more 

chronic effects and can vary widely across individuals in type and magnitude according to a host of 

factors (Busch and Hayward [2009] for a recent review). Stress reactions in humans and other vertebrates 

include various physiological changes to pulmonary, respiratory cardiac, metabolic, neuro-endocrine, 

immune, and reproductive functions; these can vary from relatively benign to very detrimental or fatal in 

some conditions. 

Direct measurements of physical stress responses in marine mammals from sound exposure are 

relatively limited (Thomas et al., 1990; Miksis et al., 2001; Romano et al., 2004), although the larger 

body of data for terrestrial mammals and other animals is available and, in some cases, may be useful 

where direct information is lacking (Wright et al., 2007a,b). The available literature for marine mammals 

indicates endocrine secretions of glucocorticoids and altered cardiovascular function in some conditions 

following relatively intense noise exposure. 

Direct physical injury can occur from exposure to high levels of sound or, more commonly, to shock 

wave pulses associated with high intensity events such as explosions. These pulses are typically short, 

peak pressures that may damage internal organs or air-filled body cavities, such as lungs (Yelverton et al., 

1973; Goertner, 1982; Young, 1991). Direct data on direct physical injury are limited to anecdotal or 

forensic investigations after accidental events because ethical considerations prevent direct empirical 

methods to measure such impacts in marine mammals. However, such observations (e.g., Todd et al., 

1996) and modeling based on impact data for the human vestibular system as well as other organs 

(e.g., lungs) for underwater sound exposures (Cudahy and Ellison, 2002) suggest that marine mammals 

can be susceptible to direct physical injury to particular organ systems and tissues following intense 

exposure, particularly where high particle motion events occur. 

Other forms of physiological damage that have been investigated and in some cases shown in marine 

mammals include the formation of gas bubble lesions and fat emboli, similar to those associated with 

human decompression sickness; these have been observed in some beaked whale species that stranded 

around naval mid-frequency sonar training exercises (Jepson et al., 2003; Fernández et al., 2005). 

Currently, these tissue impacts are thought to result from a behavioral response that changes diving 

patterns in some way and subsequently causes lesion/emboli formation, rather than as a direct physical 

effect of sound exposure (Cox et al., 2006; Zimmer and Tyack, 2007). These kinds of emboli have not 

been definitively shown in other marine mammals exposed to natural or anthropogenic sound to date. 

4.2. EFFECTS OF NOISE ON MARINE MAMMAL HEARING

Much of the scientific and regulatory attention on the impacts of noise on marine life has centered on 

the issue of how sound affects hearing in marine mammals. While the available literature on the 
H-8 Atlantic G&G Programmatic EIS

underlying issues remains quite limited compared to that available for some terrestrial species, 

considerable progress has been made in these areas, particularly in the last decade, for marine mammals. 

There have been numerous reviews of the available data on these issues (Richardson et al., 1995; Wartzok 

and Ketten, 1999; NRC, 2003, 2005), the most recent comprehensive assessment being the Southall et al. 

(2007) review and application of the available science in the context of proposing noise exposure criteria 

(see below). A summary description of temporary and permanent hearing losses and auditory masking is 

given here with reference to these reviews generally, and some discussion of more recent relevant 

literature on each issue. 

4.2.1. Temporary and Permanent Threshold Shift in Marine Mammals 

Noise-induced threshold shifts are increases in hearing thresholds within a certain frequency range 

(Yost, 2000). Following exposure, the magnitude of the threshold shift normally decreases over time 

following cessation of noise exposure. Threshold shifts can be temporary (TTS) or permanent (PTS) and 

can consist of both temporary and permanent components. Several important factors relate to the type 

and magnitude of hearing loss, including exposure level, frequency content, duration, and temporal 

pattern of exposure. A range of mechanical stress or damage (e.g., supporting cell structure fatigue) and 

metabolic (e.g., inner ear hair cell metabolism, such as energy production, protein synthesis, and ion 

transport) processes within the auditory system underlie both TTS and PTS (Yost, 2000; Kryter, 1994; 

Ward, 1997). Intense sound exposure more often results in mechanical processes, whereas prolonged 

exposure more typically results in metabolic changes (e.g., Saunders et al., 1985).

Temporary threshold shift is a relatively short-term reversible loss of hearing, often resulting from 

cellular fatigue and metabolic changes. Based on data from cetacean TTS studies (Southall et al., 2007), 

a threshold shift of 6 dB is generally considered the minimum threshold shift that is statistically larger 

than typical day-to-day or session-to-session variation in a subject’s baseline threshold at a particular 

frequency. Conversely, PTS is an irreversible loss of hearing (permanent damage) that commonly results 

from inner ear hair cell loss and/or severe damage or other structural damage to auditory tissues (e.g., 

Saunders et al., 1985; Henderson et al., 2008). Permanent threshold shift data are typically not collected 

in marine mammals owing to ethical and permitting reasons, but a recent TTS experiment was found to 

unintentionally induce PTS in a harbor seal (Kastak et al., 2008). Southall et al. (2007) reviewed the 

available terrestrial literature and concluded that 40 dB of TTS was a reasonable and conservative 

approximation of PTS onset for marine mammals (Henderson et al., 2008 for a consideration of the 

human literature in this regard). 

Temporary threshold shift has been measured in three cetacean and three pinniped species using both 

impulsive and continuous noise; many of these data were reviewed in detail by Southall et al. (2007), but 

there are some notable new data that change some of the conclusions reached in that assessment. In 

general, it appears that marine mammal auditory systems are relatively resilient to noise exposure and that 

relatively intense sounds are required to cause TTS and, given some simplifying assumptions to 

extrapolate to 40 dB TTS, PTS as well. However, there are clear differences in terms of the sound 

exposure types and some major differences between species as well. As in terrestrial mammals, marine 

mammals experience TTS at relatively lower onset levels for impulsive noise than for non-impulsive 

noise. The relative TTS onset levels for different marine mammal groups from the Southall et al. (2007) 

criteria are discussed in the section below regarding exposure criteria. However, some modifications to 

these criteria would now be in order, as expected, based on subsequent information. 

New data are available demonstrating much lower (>20 dB) TTS-onset exposure levels for harbor 

porpoises exposed to impulse noise (airguns) than has been measured in other odontocetes (Lucke et al., 

2009). These data are significant because they are the only TTS measurements available for any 

individual in the high-frequency cetacean functional hearing group and would arguably be used as the 

representative value for these species rather than using the extrapolated (though much more expansive) 

data for mid-frequency cetaceans in predicting auditory fatigue. In addition, several studies have 

contributed to an expanded understanding of TTS onset and growth at a range of sound frequencies in 

odontocete cetaceans. Mooney et al. (2009a,b) demonstrate conditions where equal energy assumptions 

about exposure of different durations and levels fail to accurately predict TTS onset and growth. 

Finneran and Schlundt (2010) and Finneran et al. (2010a,b) provide additional TTS data for bottlenose 
Marine Mammal Hearing and Sensitivity to Acoustic Impacts H-9 

dolphins, demonstrating a greater sensitivity (10-20 dB) to noise exposure (lower absolute TTS onset 

levels) and a more rapid growth of TTS with increasing noise exposure level at higher frequencies within 

their region of best sensitivity than had been tested when the Southall et al. (2007) criteria were 

published. These data suggest that the exposure level relative to the subject’s absolute hearing sensitivity 

(referred to as the sensation level) is particularly important in determining TTS onset. They also suggest 

that exposure levels in the region of best hearing sensitivity should be used as generic TTS-onset values 

against which frequency weighting functions could be applied to correct for frequency-specific hearing. 

These findings are significant for mysticetes despite being made with odontocete cetaceans, as they affect 

the selection of the appropriate TTS-onset values to apply for mysticetes from the odontocete literature 

(since no mysticete TTS values are or for the foreseeable future will be available). 

4.2.2. Auditory Masking 

In addition to potential effects on hearing from relatively high levels of sound exposure that would 

generally occur relatively close to anthropogenic sound sources in the field, noise interference 

(“masking”) effects can occur, and likely do over much greater footprints around real sound sources. 

Noise can affect hearing and partially or completely reduce an individual’s ability to effectively 

communicate, detect important predator, prey, and/or conspecific signals, and/or detect important 

environmental features associated with spatial orientation (Clark et al., 2009 for a review). Spectral, 

temporal, and spatial overlap between the masking noise and the sender/receiver determine the extent of 

interference; the greater the spectral and temporal overlap, the greater the potential for masking. 

Southall et al. (2007) considered auditory masking issues and realized the much greater relative areas 

over which this phenomena occurs relative to TTS and PTS, but did not propose explicit exposure criteria 

for marine mammals, owing in part to the very divergent conditions in which masking can occur and a 

lack of clear understanding about defining an “onset” for masking that would be statistically definable 

and biologically meaningful. Largely for the same reasons, masking effects have generally been 

considered only qualitatively in planning of activities and regulatory decisions over noise impacts. 

Subsequent data have demonstrated vocal modifications in marine mammals exposed to noise that are 

presumably the result of anthropogenic masking noise (e.g., Holt et al., 2009). Additionally, Clark et al. 

(2009) provided a quantitative means of determining the relative loss of acoustic communication range 

for marine mammals using specific calls in conditions where they are exposed to specific anthropogenic 

noise sources. 

There is particular concern that low-frequency anthropogenic noise may mask communication in 

baleen whales, which can communicate over long distances and within the same frequency band 

(e.g., Payne and Webb, 1971; Clark et al., 2009). An example of baleen whale calling behavior that is 

increasingly masked by nearby ship noise is shown in Figure H-5. 

5 10 15 20

time, minutes

20

40

60

80

100

120

0

frequency, Hz

Blue

Whale

Figure H-5. Time Series Plot Showing a Calling Blue Whale and the Increasing 

Noise (and Masking) in the Same Low-Frequency Band from an 

Approaching Vessel (courtesy of C. Clark). 
H-10 Atlantic G&G Programmatic EIS

4.3. EFFECTS OF NOISE ON MARINE MAMMAL BEHAVIOR

Behavioral responses to sound are highly variable and critically depend on the context of sound 

exposure, as much or more than the level-duration-frequency characteristics that determine the probability 

of auditory effects (Wartzok et al., 2004, Southall et al., 2007). There is a very wide range of possible 

behavioral responses to sound exposure, given that the sound is audible to the particular animal, 

including, in approximate order of increasing severity but decreasing likelihood: 

 none observable – animals can become less sensitive over repeated exposures; 

 looking or increased alertness; 

 minor behavioral responses such as vocal modifications associated with masking; 

 cessation of feeding or social interactions; 

 temporary avoidance behavior (emerging as one of the more common responses); 

 modification of group structure or activity state; 

 habitat abandonment; and/or 

 injury and/or death via direct response or possibly exacerbated by physiological 

factors. 

These effects clearly have differing probabilities to affect marine mammal vital rates (NRC, 2005), 

but it has proven (and remains) exceedingly difficult to establish a generally accepted definition and 

criterion for biologically meaningful behavioral disturbance. Assessing the severity of behavioral effects 

of anthropogenic sound exposure on marine mammals presents unique challenges associated with the 

inherent complexity of behavioral responses and the contextual factors affecting them, both within and 

between individuals and species. Severity of responses can vary depending on characteristics of the 

sound source (e.g., moving or stationary, number and spatial distribution of sound source[s], similarity to 

predator sounds, and other relevant factors) (Richardson et al., 1995; NRC, 2005; Southall et al., 2007; 

Wirsing et al., 2008; Bejder et al., 2009; Barber et al., 2010). 

Southall et al. (2007) reviewed the considerable available literature on the effects of noise on marine 

mammal hearing in extensive detail, but (other than for single impulse exposures where TTS-onset was 

used as a threshold value for behavioral disturbance) did not find a single metric or identifiable exposure 

level that was broadly applicable as a benchmark for behavioral effects. Several general observations 

were made, including that many of the responses observed across taxa were temporary avoidance 

behavior. Additionally, certain species (e.g., harbor porpoises, beaked whales) appear to be categorically 

more sensitive to noise than other species observed, and certain behavioral states (e.g., migrating) can 

make species such as bowhead whales more sensitive to exposure. Subsequent data have demonstrated 

and quantified behavioral responses of various species, including some of the Endangered Species 

Act-listed marine mammals being considered in this Programmatic Environmental Impact Statement 

(Programmatic EIS), to seismic exploration using airguns (Weir, 2008a,b; Miller et al., 2009). Additional 

data have demonstrated behavioral responses of cetaceans to vessels associated with whale-watching 

activities (e.g., Bejder and Lusseau, 2008; Visser et al., 2010) and to the construction of offshore energy 

installations (Thompson et al., 2010). Finally, there has been considerable new information, using both 

controlled exposure experiments and opportunistic observations of anthropogenic noise source operations, 

on the behavioral responses of particularly sensitive marine mammals, including harbor porpoises 

(Kastelein et al., 2008a,b; Gilles et al., 2009) and beaked whales (Caretta et al., 2008; McCarthy et al., 

2011; Southall et al., 2011; Tyack et al., 2011). These studies amplify the conclusions of Southall et al. 

(2007) that these are particularly sensitive species, although it remains unclear whether any additional 

species should be added to this general category. 

5. MARINE MAMMAL NOISE EXPOSURE CRITERIA 

Beginning in the 1980’s with regulations on oil and gas exploration, sound-producing entities and 

regulatory agencies have been grappling with how to quantitatively predict and operationally mitigate the 

effects of human noise from industrial activities on marine life. While the marine noise issue is an 

increasingly global one, many of the developments on exposure criteria for marine mammals have 

involved U.S. regulatory processes. 
Marine Mammal Hearing and Sensitivity to Acoustic Impacts H-11 

In June 1997, the High Energy Seismic Survey team (HESS, 1999) convened a panel of experts to 

assess existing data on marine mammals exposed to seismic pulses and to predict exposures at which 

physical injury could occur. With the limited available data at that time, exposure to airgun pulses with 

received levels above 180 dB re: 1μPa (root-mean-square [RMS] – averaged over the pulse duration) was 

determined to have a high potential for “serious behavioral, physiological, and hearing effects.” 

Based on the HESS (1999) panel conclusions, the National Marine Fisheries Service (NMFS) 

established a 180 dBrms (received level) threshold criterion for injury from sound exposure for cetaceans 

and a 190 dBrms threshold criterion for pinnipeds (Federal Register, 2003). Additionally, behavioral 

response criteria were developed as step-function (all-or-none) thresholds based solely on the RMS value 

of received levels, and have been used by NMFS, although not entirely consistently. Thresholds for 

behavioral response from impulse sounds are 160 dBrms (received level) for all marine mammals, based 

on behavioral response data for marine mammals exposed to seismic airgun operations (Malme et al., 

1983, 1984; Richardson et al., 1986). Thresholds for behavioral response for “continuous” 

(non-impulsive) sounds have been 120 dBrms (for some but not all sound sources) based on the results of 

Malme et al. (1984) and Richardson et al. (1990). 

Recognizing that the available data on hearing and noise impacts were rapidly evolving and that a 

more comprehensive and scientifically robust method of assessment would be required than these 

simplistic threshold estimates, NMFS supported an expert working group to develop more comprehensive 

and current marine mammal noise exposure criteria. This process ultimately resulted in the Southall et al. 

(2007) marine mammal noise exposure criteria. Within this process, several important segregations were 

made. First, the marine mammals were segregated into the functional hearing groups (not entirely 

taxonomy-based), as described above. Second, sound sources were categorized into functional categories, 

based on their acoustic and repetitive properties (Table H-2). 

Table H-2 

 

Sound Source Categories, Acoustic Characteristics, and Examples, as Proposed by Southall et al. (2007) 

Sound Type Acoustic Characteristics 

(at source) Examples 

Single Pulse 

Single acoustic event; >3 dB difference 

between received level using impulse versus 

equivalent continuous time constant 

Single explosion; sonic boom; single airgun, 

watergun, pile strike, or sparker pulse; single 

ping of certain sonars, depth sounders, and 

pingers 

Multiple Pulse 

Multiple discrete acoustic events within 24 

hr; >3 dB difference between received level 

using impulse versus equivalent continuous 

time constant 

Serial explosions; sequential airgun, 

watergun, pile strikes, or sparker pulses; 

certain active sonar (IMAPS); some depth 

sounder signals 

Non-Pulse 

Single or multiple discrete acoustic events 

within 24 h; <3 dB difference between 

received level using impulse versus 

equivalent continuous time constant 

Vessel/aircraft passes, drilling; many 

construction or other industrial operations; 

certain sonar systems (LFA; tactical 

mid-frequency); acoustic 

harassment/deterrent devises; acoustic 

tomography sources (ATOC); some depth 

sounder signals 

IMAPS = Integrated Marine Mammal Monitoring and Protection System. 

LFA = Low-Frequency Active.

ATOC = Acoustic Thermometry of Ocean Climate. 

Additionally, the potential for hearing and behavioral effects for noise exposures of these different 

categories was assessed for each of the different functional hearing groups according to a wider and more 

applicable set of acoustic exposure metrics. For hearing impacts, this included the sound energy (sound 

exposure level), which accounts for amplitude level and duration, as well as peak sound pressure. For 
H-12 Atlantic G&G Programmatic EIS

behavioral effects, the conventional RMS levels for sound exposure were considered, in part because this 

is typically all of the information available regarding available studies. 

As described briefly above, Southall et al. (2007) proposed explicit and numerical exposure level 

values for injury from sound exposure for each of the marine mammal functional hearing groups. Using 

measured onset-TTS levels where possible (or extrapolating them from related species where not) and a 

series of extrapolation procedures to estimate the growth of TTS and a reasonably conservative estimate 

of physical injury (40 dB TTS as described above), received level threshold values were determined. For 

sound exposure level values, the frequency weighting functions described above would be applied to the 

received sound to account for differential frequency sensitivity among the different marine mammal 

groups. The resulting thresholds for injury from sound exposure for different marine mammal groups, via 

these general methods and using all available relevant data as proposed by Southall et al. (2007), are 

summarized in Table H-3. 

Table H-3 

 

Marine Mammal Noise Exposure Criteria for Injury for Different Marine Mammal Functional Hearing Groups 

Proposed by Southall et al. (2007) 

Sound Type Marine Mammal Group Single Pulses Multiple Pulses Non-Pulses 

Low-frequency Cetaceans Cell 1 Cell 2 Cell 3 

Sound Pressure Level 230 dBpeak re: 1μPa (flat) 230 dBpeak re: 1μPa (flat) 230 dBpeak re: 1μPa (flat) 

Sound Exposure Level 198 dB re: 1μPa2-s (Mlf) 198 dB re: 1μPa2-s (Mlf) 215 dB re: 1μPa2-s (Mlf) 

Mid-frequency Cetaceans Cell 4 Cell 5 Cell 6 

Sound Pressure Level 230 dBpeak re: 1μPa (flat) 230 dBpeak re: 1μPa (flat) 230 dBpeak re: 1μPa (flat) 

Sound Exposure Level 198 dB re: 1μPa2-s (Mmf) 198 dB re: 1μPa2-s (Mmf) 215 dB re: 1μPa2-s (Mmf) 

High-frequency Cetaceans Cell 7 Cell 8 Cell 9 

Sound Pressure Level 230 dBpeak re: 1μPa (flat) 230 dBpeak re: 1μPa (flat) 230 dBpeak re: 1μPa (flat) 

Sound Exposure Level 198 dB re: 1μPa2-s (Mhf) 198 dB re: 1μPa2-s (Mhf) 215 dB re: 1μPa2-s (Mhf) 

Pinnipeds (in water) Cell 10 Cell 11 Cell 12 

Sound Pressure Level 218 dBpeak re: 1μPa (flat) 218 dBpeak re: 1μPa (flat) 218 dBpeak re: 1μPa (flat) 

Sound Exposure Level 186 dB re: 1μPa2-s (Mpw) 186 dB re: 1μPa2-s (Mpw) 203 dB re: 1μPa2-s (Mpw) 

Pinnipeds (in air) Cell 13 Cell 14 Cell 15 

Sound Pressure Level 149 dBpeak re: 20μPa (flat) 149 dBpeak re: 20μPa (flat) 149 dBpeak re: 20μPa (flat) 

Sound Exposure Level 144 dB re: (20μPa)2-s (Mpa) 144 dB re: (20μPa)2-s (Mpa) 144.5 dB re: (20μPa)2-s (Mpa)

Several notable features of these criteria are the relatively high received level values predicted 

necessary to induce injury and that all of the cetaceans have numerically-identical threshold values, with 

the exception of the frequency-weighting functions. The former is simply a function of the relatively high 

TTS-onset values in the marine mammal species tested thus far. The latter is the case because at the time 

of the Southall et al. (2007) criteria paper, there were no direct data on auditory fatigue in low- or 

high-frequency cetaceans, and the mid-frequency cetacean TTS-onset levels were used for these other 

groups. Subsequently, the Lucke et al. (2009) results have shown significantly lower onset values for 

TTS in high-frequency cetaceans; these will presumably be applied for these species. For low-frequency 

cetaceans, some of the subsequent TTS data for mid-frequency cetaceans in regions of best sensitivity 

(Finneran and Schlundt, 2010) may be applicable in considering the appropriate TTS-onset value to 

extrapolate to the mysticetes, which are highly unlikely to test in a controlled hearing study to measure 

auditory fatigure. Finally, these newer TTS measurements in mid-frequency cetaceans (Finneran and 

Schlundt, 2010; Finneran et al., 2010a,b) will require reanalysis of the appropriate TTS-onset (and thus 

injury onset) point for this category as well. Such improvements based on additional data were 

envisioned, and in most cases specifically called for in terms of experimental approaches and priorities, 

and the conclusions and threshold values will continue to evolve over time. Despite the expected 

requisite re-thinking based on new data, the Southall et al. (2007) approach to marine mammal noise 
Marine Mammal Hearing and Sensitivity to Acoustic Impacts H-13 

exposure represented a major evolution in the complexity and scientific basis for predicting the effects of 

noise on hearing in marine mammals over the extremely simplistic historical NMFS thresholds for injury. 

In terms of behavioral impacts, the Southall et al. (2007) noise exposure criteria took a dual approach 

depending on the sound type. For exposure to single impulses (e.g., explosion), the acoustic component 

of the event was considered sufficiently intense to constitute behavioral harassment at levels consistent 

with TTS onset (Table H-4). The logic for this was that since these events are so brief and transient that 

any responses other than those affecting hearing would likely be similarly transient in nature and thus not 

affect the long-term health or fitness of animals. It was noted, however, that startle responses can trigger 

stress and other physiological responses, the biological significance of which remains poorly understood. 

Table H-4 

 

Marine Mammal Noise Exposure Criteria for Behavior for Different Marine Mammal 

Functional Hearing Groups Proposed by Southall et al. (2007) 

Sound Type Marine Mammal Group Single Pulses Multiple Pulses Non-Pulses 

Low-frequency Cetaceans Cell 1 Cell 2 Cell 3 

Sound Pressure Level 224 dBpeak re: 1μPa (flat) see Tables 6 & 7 in 

Southall et al., 2007 

see Tables 14 & 15 in 

Southall et al., 2007 

Sound Exposure Level 183 dB re: 1μPa2-s (Mlf) Not applicable Not applicable 

Mid-frequency Cetaceans Cell 4 Cell 5 Cell 6 

Sound Pressure Level 224 dBpeak re: 1μPa (flat) see Tables 8 & 9 in 

Southall et al., 2007 

see Tables 16 & 17 in 

Southall et al., 2007 

Sound Exposure Level 183 dB re: 1μPa2-s (Mmf) Not applicable Not applicable 

High-frequency Cetaceans Cell 7 Cell 8 Cell 9 

Sound Pressure Level 224 dBpeak re: 1μPa (flat) see Tables 18 & 19 in 

Southall et al., 2007 

see Tables 18 & 19 in 

Southall et al., 2007 

Sound Exposure Level 183 dB re: 1μPa2-s (Mhf) Not applicable Not applicable 

Pinnipeds (in water) Cell 10 Cell 11 Cell 12 

Sound Pressure Level 212 dBpeak re: 1μPa (flat) see Tables 10 & 11 in 

Southall et al., 2007 

see Tables 20 & 21 in 

Southall et al., 2007 

Sound Exposure Level 171 dB re: 1μPa2-s (Mpw) Not applicable Not applicable 

Pinnipeds (in air) Cell 13 Cell 14 Cell 15 

Sound Pressure Level 109 dBpeak re: 20μPa (flat) see Tables 12 & 13 in 

Southall et al., 2007 

see Tables 22 & 23 in 

Southall et al., 2007 

Sound Exposure Level 100 dB re: (20μPa)2

-s 

(Mpa) Not applicable Not applicable 

For all other sound types (which are the majority), Southall et al. (2007) did not propose explicit 

threshold criteria, for the reasons of context-dependence and other complexities in the nature of 

behavioral responses and available literature described above. It was concluded that significant 

behavioral effects would likely occur at exposure levels below those required for TTS and PTS, but that 

simple step-function thresholds for behavior (such as the historical NMFS values) were simply 

inconsistent with the best available science. While an overarching exposure level approach for behavior 

as seems reasonable for injury is perhaps more convenient from an assessment standpoint, the underlying 

reasons behind the type and magnitude of behavioral response involve a multitude of factors and require a 

multivariate assessment method to adequately describe. 

To begin addressing some of these issues Southall et al. (2007) derived a severity scaling to attempt 

for the first time to put some reasonable bounds on the likely significance of observed responses, 

highlighting the importance of responses with the potential to affect vital rates and survivorship (as in 

NRC, 2005). An ordinal ranking of behavioral response severity (see Table 4 in Southall et al., 2007) was 

developed, the intent being to delineate behaviors that are relatively minor and/or brief from those 
H-14 Atlantic G&G Programmatic EIS

considered more likely to affect these vital rates. The observed behavioral responses in all 10 conditions 

for multiple pulses and continuous noise for each of the five functional hearing groups were reviewed in 

detail, and individual responses were assessed according to this severity scaling and measured or 

reasonably estimated exposure levels. An example of this severity scaling of the observed behavioral 

literature in one of these conditions (low-frequency cetaceans exposed to impulse noise, predominantly 

airguns) that may be particularly relevant to this assessment is shown in Table H-5. Blank cells in this 

table indicate the lack of measured responses for these received sound levels and response categories; an 

overarching conclusion of Southall et al. (2007) was the striking lack of data in most exposure conditions 

for marine mammals. 

This severity scaling, as evident in Table H-5, did not reveal broadly applicable patterns of response 

in most cases – i.e., where no response occurs below some specific received level and a high probability 

of response occurs above some point (as step-functions would presume). Certain observations were 

made, including the behavioral context-dependence of response for different received levels in migrating 

bowhead whales and the particular sensitivity of harbor porpoises both in field and laboratory 

experiments. But the primary advances made in the Southall et al. (2007) criteria in terms of behavioral 

response were to very clearly demonstrate that step-function thresholds for response using a single 

received level and no other considerations related to behavioral context are overly simplistic and outdated 

and to develop at least a qualitative means of addressing behavioral response severity issues. 

Table H-5 

 

Southall et al. (2007) Assessment of Individual Behavioral Responses of Low-Frequency Cetaceans to 

Multiple-Pulse Exposure for Various Received Levels 

(Individual observations are weighted to account for statistical considerations, and source data are indicated by 

parenthetical subscript: Malme et al. (1983)1

; Malme et al. (1984)2; Richardson et al. (1986)3; Ljungblad et al. 

(1988)4

; Todd et al. (1996)5; McCauley et al. (1998)6; Richardson et al. (1999)7; and Miller et al. (2005)8

Received Exposure Level (dBRMS re: 1μPa) Response 

Score 80 to 

<90 

90 to 

<100 

100 to 

<110 

110 to

<120 

120 to

<130 

130 to

<140 

140 to

<150 

150 to 

<160 

160 to

<170 

170 to 

<180 

180 to

<190 

190 to

<200 

9 

8 

7 1 

(6) 

6 9.5 

(3,7) 

47.4 

(3,7)

2.2 

(3,7)

1.4 

(4)

2 

(1,2)

5.5 

(1,2,4,6)

9.3 

(1,2,4,6,8)

5 1 

(3,7)

1 

(4)

1 

(1,2)

4 

3 1 

(1,2)

1 

(1,2)

2 

1 5 

(3,7)

6 

(3,7)

1 

(3,7)

2 

(1,2)

3 

(5)

0 59.8 

(3,7)

17.7 

(3,7)

1.1 

(3,7,8)

0.1 

(8)

0.1 

(8)

6.8 

(1,2,8)

6.3 

(1,2,8)

Clearly, the Southall et al. (2007) criteria for behavior are a starting point to develop a rudimentary 

framework in moving toward a more multivariate and biologically-meaningful way of assessing the type 

and magnitude of behavioral responses of marine mammals to noise than historical thresholds. As 

evidenced by the absence of data in many exposure level and response types above, significant data gaps 

exist in almost all areas, and many of the available studies lack key information about the nature of 
Marine Mammal Hearing and Sensitivity to Acoustic Impacts H-15 

exposure in which behavioral responses were observed (which is why many studies were excluded from 

the Southall et al. [2007] analysis). This is an active area of research, and subsequent studies (some 

described above) have begun to report additional information on background noise, various exposure 

metrics, and behavioral contexts. 

Broad application of the Southall et al. (2007) criteria for both injury and behavior has been relatively 

slow in evolving, in part due to the increased complexity of the recommendations over the previous 

simplistic approaches, such as step-functions used by NMFS. However, NMFS has used exposure criteria 

consistent with the Southall et al. (2007) thresholds for injury from sound exposure for assessing potential 

impacts of Navy active sonar operations (Federal Register, 2009a,b) for a host of species, including large 

whales and pinnipeds. In fact, these regulations actually include higher exposure values for certain 

species for which higher TTS onset values were directly measured than the more conservative values used 

in Southall et al. (2007). Additionally, recent NMFS regulations (Federal Register, 2009a,b) have also 

begun to use a more graduated dose-function based approach to behavioral response rather than the 

historical step-function thresholds. NMFS is preparing acoustic exposure guidelines that are expected to 

increasingly consider the increased complexity and context-dependence of responses of marine mammals 

to sound. 

6. ASSESSMENT OF HEARING INFORMATION FOR 

SPECIES/GROUPS IN THE AREA OF INTEREST 

Specific sound sources that will be used in G&G exploration activities off the U.S. East Coast, as 

discussed in Chapter 3 of the Programmatic EIS, include both impulsive (e.g., 2D and 3D seismic 

exploration surveys using conventional airguns) and continuous noise sources such as side-scan sonars, 

sediment sampling, electromagnetic surveys, and various vessel activities. 

Most of the marine mammals likely to be present in the Area of Interest (AOI), as discussed in 

Programmatic EIS Chapter 4.2.2, are cetaceans, with some pinnipeds possibly present at very low 

densities in the northern extent of the area and manatees potentially present in southern, near-coastal 

waters. For some of these species (e.g., bottlenose dolphins), relatively good information exists about 

hearing and behavioral responses to some types of sounds (e.g., Nowacek et al., 2001), though not 

particularly for seismic exploration specifically. For most of the mid-frequency cetacean species, 

including the endangered sperm whale, the injury criteria proposed by Southall et al. (2007) and general 

conclusions on behavioral response would be expected to be applicable; direct recent information on 

behavioral responses in sperm whales to seismic airguns are available as well (e.g., Miller et al., 2009). 

For West Indian manatees, direct measurements of hearing are available (Gerstein et al., 1999; Mann 

et al., 2005), as well as responses to vessel presence and noise (Nowacek et al., 2004a). From the 

perspective of hearing injury, the use of pinniped exposure criteria from the Southall et al. (2007) criteria 

would seem reasonable, as described above. These animals are generally very coastal-oriented, which 

would likely mean they would encounter G&G activities only in nearshore waters. 

For the endangered mysticetes that occur in the area (north Atlantic right whale, blue whale, fin 

whale, humpback whale, and sei whale), as for all low-frequency cetaceans, no direct information 

regarding hearing is available. As described above, the Southall et al., 2007 exposure criteria for injury 

are based on assumptions and extrapolations from mid-frequency cetacean data that may need to be 

reassessed to some degree based on the subsequent measurements of lower onset TTS levels in bottlenose 

dolphins within their range of best hearing sensitivity (Finneran and Schlundt, 2010). In terms of 

behavioral response, substantial effort has been made and data are available for impulse noise (seismic 

airguns specifically) for mysticetes, though not for all of the species present in the AOI. Nowacek et al. 

(2004b) showed that north Atlantic right whales may be particularly responsive to alarm-like 

non-impulsive noise in controlled exposure studies. Similarly and more recently, Southall et al. (2011) 

demonstrated behavioral responses, and an apparent context-dependence in response based on behavioral 

state, in some blue and fin whales exposed to simulated sonar sounds off the coast of California. The fact 

that many of the mysticetes in the AOI may be engaged in migratory behavior during the course of 

operations, the increased sensitivity of some other mysticetes (e.g., bowhead and gray whales) during 

migrations should be considered in assessing potential responses of species where no direct data on 

responses to certain sound types (airguns) are available (e.g., blue, fin, and sei whales). 
H-16 Atlantic G&G Programmatic EIS

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APPENDIX I 

 

SEA TURTLE HEARING AND

SENSITIVITY TO ACOUSTIC IMPACTS

Sea Turtle Hearing and Sensitivity to Acoustic Impacts I-iii 

TABLE OF CONTENTS 

Page 

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

2. MORPHOLOGY ............................................................................................................................... I-1

3. ELECTROPHYSIOLOGICAL RESPONSE TO SOUND................................................................ I-2

4. BEHAVIORAL RESPONSES TO SOUND...................................................................................... I-3

5. EFFECTS OF ANTHROPOGENIC NOISE ..................................................................................... I-4

6. REFERENCES CITED...................................................................................................................... I-5

Sea Turtle Hearing and Sensitivity to Acoustic Impacts I-1 

1. INTRODUCTION 

There is growing concern over anthropogenic sound in the world’s oceans and its potentially harmful 

effects on protected marine organisms, including sea turtles. Similar to other migratory marine species, 

sea turtles occupy different ecological niches throughout ontogeny, each characterized by unique acoustic 

conditions. Sea turtles spend the majority of their lives in the ocean; their only land-linked behaviors are 

egg deposition and hatching. Like many marine fishes and mammals, sea turtles use a range of habitats 

for each developmental stage (see review by Bolton, 2003). Once hatchlings reach the sea, they are 

pelagic, moving primarily with ocean currents. After a period of years, which varies both among species 

and populations, a critical ontogenetic habitat shift occurs whereby most sea turtles actively recruit to a 

demersal, neritic habitat and are considered juveniles. Finally, upon reaching maturity, all sea turtles 

maintain a discrete foraging area (this region frequently overlaps with the juveniles), migrating only to 

return to their natal nesting beach. The exception to this life history model in North Atlantic populations 

is the leatherback turtle (Dermochelys coriacea). Leatherbacks remain pelagic as both juveniles and 

adults and return to the neritic zone only for reproduction (Bolton, 2003). 

Few studies have examined the role acoustic cues play in the ecology of sea turtles (Mrosovsky, 

1972; Samuel et al., 2005; Nunny et al., 2008). There is evidence that sea turtles may use sound to 

communicate; the few vocalizations described for sea turtles are restricted to the “grunts” of nesting 

females (Mrosovsky, 1972). These sounds are low frequency and relatively loud, thus leading to 

speculation that nesting females use sounds to communicate with conspecifics (Mrosovsky, 1972). We 

know very little about the extent to which sea turtles use their auditory environment (“soundscape”). 

However, the passive acoustic environment for sea turtles changes with each ontogenetic habitat shift. In 

the inshore environment where juvenile and adult sea turtles generally reside, the ambient environment is 

noisier than the open ocean environment of the hatchlings; this inshore environment is dominated by low 

frequency sound (Hawkins and Myrberg, 1983), and, in highly trafficked areas, virtually constant low 

frequency noises from shipping, recreational boating, and seismic surveys compound the potential for 

acoustic impact (Hildebrand, 2005). 

2. MORPHOLOGY 

Much of the research on the hearing capacity of sea turtles is limited to gross morphological 

dissections (Wever, 1978; Lenhardt et al., 1985). The tympanum is a continuation of the facial tissue and 

is distinguishable only by palpitation of the area. Beneath the tympanum is a thick layer of subtympanal 

fat (Figure I-1), a feature that distinguishes sea turtles from both terrestrial and semi-aquatic turtles. 

Recent imaging data suggests that this layer of fat is similar to the fats found in the jaws of odontocete 

whales and functions as a low-impedance channel for sounds to the ear (Ketten et al., 1999). The middle 

ear cavity lies posterior to the tympanum; the Eustachian tube connects the middle ear with the throat 

(Wever, 1978; Lenhardt et al., 1985). As with most turtles, the middle ear is small and encased by bone. 

The ossicular mechanism consists of two elements: the extracolumella and the columella (stapes). The 

extracolumella is a cartilaginous disk under the tympanic membrane attached to the columella by 

ligaments. The columella, a long rod with the majority of its mass concentrated at each end, extends 

medially from the middle ear cavity through a narrow bony channel and expands within the oval window 

to form a funnel shaped end. The columella is free to move only longitudinally within this channel so 

when the tympanum is depressed directly above the middle of the extracolumella, the columella moves 

readily in and out of the oval window, without any flexion of the columella. The stapes and oval window 

are connected to the saccular wall by fibrous strands. It is thought that these stapedo-saccular strands 

relay vibrational energy of the stapes to the saccule (Wever and Vernon, 1956; Wever, 1978; Lenhardt et 

al., 1985). For semi-aquatic turtles, the columella is the main pathway for sound input to the inner ear; 

when the columella is clipped while leaving the tympanum intact, the animal displayed an extreme 

decrease of sensitivity of hearing (Wever and Vernon, 1956). 
I-2 Atlantic G&G Programmatic EIS

Figure I-1. Middle Ear Anatomy of the Juvenile Loggerhead Sea Turtle (Moein, 1994). 

The auditory sense organ within the inner ear of the sea turtle cochlea is the basilar papilla (basilar 

membrane). This membrane is large and composed of dense connective tissue in sea turtles (rather than a 

thin basilar membrane found in terrestrial turtles) (Wever, 1978; Hetherington, 2008). This basilar papilla 

is positioned opposite the round window and lies within the pathway of fluid displacement due to 

columella motion. In most reptiles, and presumably in sea turtles as well, the tectorial membrane lays 

over the hair cells of the basilar papilla. For sea turtles, the innervations of the hair cells may be 

accomplished through the movement of the overlying tectorial membrane rather than the movement of the 

papillae (Hetherington, 2008). 

Based on the functional morphology of the ear, it appears that sea turtles receive sound through the 

standard vertebrate tympanic middle ear path. This ear, however, is adapted to underwater sound, not 

aerial. For the terrestrial vertebrate, the middle ear is an impedance transformer between sound in air 

(environment) and sound in fluid (inner ear). This impedance mismatch can be overcome by having a 

high convergence ratio between the tympanic membrane and oval window (thus amplifying the force 

acting on the inner ear) and by having a multiple bone ossicular mechanism that acts as a lever system to 

amplify force. The convergence ratio of the tympanic membrane to oval window in sea turtles is reported 

to be lower than other semi-aquatic turtles (Lenhardt et al., 1985), and sea turtles lack an osscicular 

mechanism that acts as a lever (having only a single straight columella). Thus, the sea turtle ear appears 

to be a poor receptor for aerial sounds. However, this ear is well adapted to water conduction sound. The 

dense layer of fat under the tympanum acts as a low-impedance channel for underwater sound (similar to 

that pathway found in odontocetes [Ketten et al., 1999]). Furthermore, the retention of air in the middle 

ear of these sea turtles suggests that they are able to detect sound pressures. 

3. ELECTROPHYSIOLOGICAL RESPONSE TO SOUND 

Electrophysiological studies on hearing have been conducted on juvenile green turtles (Chelonia 

mydas) (Ridgway et al., 1969; Bartol and Ketten, 2006), juvenile Kemp’s ridley turtles (Lepidochelys 

kempii) (Bartol and Ketten, 2006), and juvenile loggerhead turtles (Caretta caretta) (Bartol et al., 1999; 
Sea Turtle Hearing and Sensitivity to Acoustic Impacts I-3 

Lavender et al., 2010, 2011). Electrophysiological responses, specifically auditory evoked potentials 

(AEPs), are the most widely accepted technique for measuring hearing in situations in which normal 

behavioral testing is impractical. The AEPs reflect the synchronous discharge of large populations of 

neurons within the auditory pathway and, thus, are useful monitors of the functioning of the throughput of 

the auditory system. Most AEP research has concentrated on the use of responses occurring within the 

first 10 ms following presentation of click or brief tone burst stimuli. This response has been termed the 

auditory brainstem response (ABR) and consists of a series of 5-7 patterned and identifiable waves. 

Corwin et al. (1982) recorded AEPs from five classes of non-mammalian vertebrates (including the red 

eared turtle, Pseudemys scripta elegans) and found the response, recorded outside the brain, to be 

congruous with the criteria for “conventional” ABRs. Furthermore, these techniques are noninvasive and 

can be performed on conscious subject animals (Bullock, 1981; Corwin et al., 1982). 

Ridgway et al. (1969) measured auditory cochlear potentials of green turtles using both aerial and 

vibrational stimuli. Thresholds were not measured; instead, cochlear response curves of 0.1 μV potential 

were plotted for frequencies ranging from 50 to 2,000 Hz. Green turtles detect a limited frequency range 

(200-700 Hz) with best sensitivity at the low tone region of about 400 Hz. Though this investigation 

examined two separate modes of sound reception (i.e., air and bone conduction), sensitivity curves were 

relatively similar, suggesting that the inner ear is the main structure for determining frequency sensitivity. 

To measure electrophysiological responses to sound stimuli, Bartol et al. (1999) collected ABRs from 

juvenile loggerhead turtles. Vibratory stimuli were delivered directly to the dermal plates over the 

loggerhead turtle’s tympanum. Thresholds were recorded for both tonal and click stimuli. Best 

sensitivity was found in the low frequency region of 250-1000 Hz. The decline in sensitivity was rapid 

after 1,000 Hz, and the most sensitive threshold tested was at 250 Hz. More recently, Bartol and Ketten 

(2006) collected underwater ABRs from hatchling and juvenile loggerhead and juvenile green turtles. For 

these experiments, the speaker was suspended in air while the turtle’s tympanum remained submerged 

underwater. All turtles tested responded to sounds in the low frequency range, from at least 100 Hz 

(lowest frequency tested) to no greater than 900 Hz. Interestingly, the smallest turtles tested, hatchling 

loggerheads, had the greatest range of hearing (100-900 Hz) while the larger juveniles responded to a 

much narrower range (100-400 Hz). Hearing sensitivity of green turtles also varied with size; smaller 

greens had a broader range of hearing (100-800 Hz) than that detected in larger subjects (100-500 Hz). 

Lavender et al. (2010, 2011) have recorded underwater AEPs using a Navy J9 underwater speaker from 

loggerhead turtles, their ages ranging from yearlings to subadults. Under these conditions, loggerheads 

were found to respond to frequencies between 50-1000 Hz. 

4. BEHAVIORAL RESPONSES TO SOUND 

Multiple studies have attempted to examine the behavioral responses of juvenile loggerheads to sound 

in their natural environment, both in controlled settings (O’Hara and Wilcox, 1990; Moein et al., 1995; 

McCauley et al., 2000; Lavender et al., 2011) and as observed in situ (Holst et al., 2007; Weir, 2007; 

DeRuitter and Doukara, 2010). Behavioral audiograms have been collected from multiple size classes of 

loggerhead turtles (Lavender et al., 2011). Behavioral audiograms require the animal to perform a task in 

the presence of auditory stimuli; though time consuming (it can take months to train a turtle to sound), 

behavioral audiograms are a more sensitive measure of hearing threshold than electrophysiological 

responses and ascribe a critical behavioral component to hearing trials. Lavender et al. (2011) recorded 

audiograms using a two-response, forced-choice approach, whereby the turtles were required to vary 

behavior according to presence or absence of sound, permitting a behavioral measure of acoustic 

sensitivity. Lavender et al. (2011) have found that while loggerheads respond to similar frequencies as 

previous studies (50-1,000 Hz), their threshold levels are actually more sensitive than reported using 

electrophysiological methods. 

Several sea turtle behavioral studies have been initiated to assist in the development of an acoustic 

repelling device for sea turtles. O’Hara and Wilcox (1990) attempted to create a sound barrier for 

loggerhead turtles at the end of a canal using seismic airguns. The test results indicated that airguns were 

effective as a deterrent for a distance of about 30 m when the sound output of this system was 

approximately 220 dB re 1 Pa at 1 m in the 25-1,000 Hz range. However, this study did not account for 

the reflection of sound by the canal walls, and the stimulus frequency and intensity levels are ambiguous. 

Moein et al. (1995) investigated the use of airguns to repel juvenile loggerhead turtles from hopper 
I-4 Atlantic G&G Programmatic EIS

dredges. A net enclosure was erected in the York River, Virginia to contain the turtles, and an airgun was 

stationed at each end of the net. Sound frequencies of the airguns ranged from 100 to 1,000 Hz at three 

decibel levels (175, 177, and 179 dB re 1 Pa at 1 m). Avoidance of the airguns was observed upon first 

exposure. However, after three separate exposures to the airguns, the turtles habituated to the stimuli. 

McCauley et al. (2000) examined the response of sea turtles (one green and one loggerhead turtle) to an 

airgun signal. For these trials, the turtles were placed in cages, and behavior was monitored as a single 

airgun approached and departed. During these trials, the turtles showed a noticeable increase in 

swimming behavior when the airgun level was above 166 dB re 1 Pa at 1 m and became erratic and 

increasingly agitated above 175 dB. Because these animals were caged, avoidance behavior could not be 

monitored. However, the researchers speculated that avoidance would occur at 175 dB re 1 Pa at 1 m, 

the point at which the animals were acutely agitated (McCauley et al., 2000). 

Researchers have also attempted to monitor sea turtle avoidance to sound during an active seismic 

survey (Weir, 2007; DeRuiter and Doukara, 2010). Weir (2007) observed 240 animals during a 10-month 

seismic survey off the coast of Angola. Behaviors were recorded at time of first sighting and as the vessel 

and towed equipment moved in relation to the turtle. Fewer turtles were observed near the airguns as they 

were firing (as opposed to the “gun-off” state). However, the source of agitation for the turtle could not 

be identified; the turtle could have reacted to the ship and towed equipment rather than specifically to the 

airgun (Weir, 2007). DeRuiter and Doukara (2010) observed turtles during active operation of an airgun 

array as well and found a startle response (rapid dive) to the airgun. However, again, these authors could 

not distinguish the stimulus source of the startle response as they did not perform a control with the 

airguns off (DeRuiter and Doukara, 2010). 

5. EFFECTS OF ANTHROPOGENIC NOISE 

There is growing concern over anthropogenic sound in the world’s oceans and the potentially harmful 

effect it has on protected marine organisms. Anthropogenic noises can originate from a multitude of 

sources, including (but not limited to) shipping traffic, seismic surveys for petroleum exploration, military 

sonar operations, pile driving, etc. These sounds have the potential to impact an animal in several ways: 

trauma to hearing (temporary or permanent), trauma to non-hearing tissue (barotraumas), alteration of 

behavior, and masking of biologically significant sounds (McCarthy, 2004). 

Hearing damage is usually categorized as either a temporary or permanent injury. Temporary 

threshold shifts (TTS) are recoverable injuries to the hearing structure and can vary in intensity and 

duration. Normal hearing abilities return over time; however, animals often lack the ability to detect prey 

and predators and assess their environment during the recovery period. In contrast, permanent threshold 

shifts (PTS) are permanent loss of hearing through loss of sensory hair cells (Clark, 1991). Few studies 

have looked at hair cell damage in reptiles, and it is still unknown if sea turtles are able to regenerate hair 

cells (Warchol, 2011). There are almost no data on the effects of intense sounds on marine turtles and, 

thus, it is difficult to predict the level of damage to hearing structures. Clear avoidance reactions to 

seismic signals at levels between 166-179 dB re 1μPa have been observed (Moein et al., 1995; McCauley 

et al., 2000); however, both of these studies were done in a caged environment, so the extent of avoidance 

could not be monitored. Moein et al. (1995) did observe a habituation effect to the airguns; the animals 

stopped responding to the signal after three presentations. This lack of behavioral response could be a 

result of TTS or PTS. 

The BOEM concludes that there is incomplete or unavailable information (40 CFR 1502.22) about 

sea turtles that use the AOI with respect to their physiology and behavioral response to intense sounds. 

The available data and information about sea turtles using the AOI is reported to the best of our ability in 

this document. The BOEM has used what scientifically credible information is available and applied it 

using accepted scientific methodologies. What is known about representative species, however, in 

combination with observation and interpretation of behavioral response to stimuli does allow some 

inferences to be drawn that allow reasonably foreseeable significant adverse impacts on sea turtles to be 

understood well enough so that mitigations can be designed to avoid or reduce them. 

The BOEM has determined that incomplete or unavailable data or information on sea turtle 

physiology and behavioral response to intense sounds is adequate to understand reasonably foreseeable 

adverse impacts and is not essential to a reasoned choice among the alternatives, including the No Action 

alternative. 
Sea Turtle Hearing and Sensitivity to Acoustic Impacts I-5 

Anthropogenic noises below injury level have the potential to mask relevant sounds in the animals’ 

environment. Masking sounds can interfere with the acquisition of prey or mate, the avoidance of 

predators, and, particularly in the case of sea turtles, identification of an appropriate nesting site (Nunny 

et al., 2008). Sea turtles appear to be low frequency specialists and, thus, the potential masking noises 

would fall within at least 50-1,000 Hz. These maskers could have diverse origins, ranging from natural to 

anthropogenic sounds (Hildebrand, 2005). The overall behavioral changes that can occur due to 

obscuration of sound scenery can have major ecological consequences for sea turtles. However, there are 

no quantitative data demonstrating masking effects for sea turtles. 

Clearly, more research on the behavioral and physiological responses to sounds needs to be conducted 

on sea turtles before appropriate noise exposure criteria can be developed for reduced fitness, injury, and 

death. While the research community is making progress in the frequency range of hearing for sea turtles, 

there are few data on hearing loss/damage, hair cell regeneration, masking, and behavioral responses. 

Inner ear research on hair cell population needs to be conducted on multiple species and multiple age 

classes by using histology/imaging techniques to analyze variations in auditory anatomy among stages 

and species. The critical point that noise disrupts scene analysis and masks signals should be explored 

and quantitative data on masking needs to be collected for sea turtles. When looking at behavioral 

responses, research beyond the “startle response” must be conducted. Controlled experiments in the 

natural environment need to be conducted to document and classify reactions to sound as either nuisance 

(i.e., causing the animal to move away, changing the animals’ behavior to another acceptable 

consequence) or injurious (i.e., preventing the animal from completing essential behavior). The results of 

these research studies could provide new data on the hearing ability and response to sound for sea turtles 

and a quantitative base for assessing potential impact of man-made sound sources on multiple species of 

sea turtles across habitats and developmental stages.

6. REFERENCES CITED 

Bartol, S.M. and D.R. Ketten. 2006. Turtle and tuna hearing. In: Y. Swimmer and R. Brill (eds.), Sea 

turtle and pelagic fish sensory biology: Developing techniques to reduce sea turtle bycatch in 

longline fisheries. Pp. 98-105. NOAA Tech. Mem. NMFS-PIFSC-7. Internet website: http://

www.pifsc.noaa.gov/tech/NOAA_Tech_Memo_PIFSC_7.pdf. Accessed August 5, 2011. 

Bartol, S.M., J.A. Musick, and M. Lenhardt. 1999. Auditory evoked potentials of the loggerhead sea 

turtle (Caretta caretta). Copeia 3:836-840. 

Bolton, A.B. 2003. Variation in sea turtle life history patterns: neritic vs. oceanic developmental stages, 

pp. 243-257. In: P.L. Lutz, J.A. Musick, and J. Wyneken (eds.), The Biology of Sea Turtles Vol. 2. 

Boca Raton: CRC Press. Internet website: http://books.google.com/books?id=

IBwouTV8VEwC&printsec=frontcover&dq=lutz+The+Biology+of+Sea+Turtles+volume+2&hl=

en&ei=DJo5TpjKKu240AHhtIDuAw&sa=X&oi=book_result&ct=book-thumbnail&resnum=1&ved

=0CC0Q6wEwAA#v=onepage&q&f=false. Accessed August 5, 2011. 

Bullock, T.H. 1981. Neuroethology deserves more study of evoked responses. Neuroscience 

6:1203-1215. 

Clark, W.W. 1991. Recent studies of temporary threshold shift (TTS) and permanent threshold shift 

(PTS) in animals. J. Acoust. Soc. Am. 90(1):155-163. 

Corwin, J.T., T.H. Bullock, and J. Schweitzer. 1982. The auditory brain stem response in five vertebrate 

classes. Electroenceph. Clin. Neurophysiol. 54(6):629-641. 

DeRuitter, S.L. and K.L. Doukara. 2010. Loggerhead turtles dive in response to airgun sound exposure. 

J. Acoust. Soc. Am. 127(3):1726. 

Hawkins, A.D. and A.A. Myrberg, Jr. 1983. Hearing and sound communication under water, 

pp. 347-405. In: B. Lewis (ed.), Bioacoustics: A Comparative Approach. Academic Press: 

London. 
I-6 Atlantic G&G Programmatic EIS

Hetherington, T. 2008. Comparative anatomy and function of hearing in aquatic amphibians, reptiles, 

and birds, pp. 183-210. In: J.G.M. Thewissen and S. Nummela (eds.), Sensory Evolution on the 

Threshold: Adaptations in Secondarily Aquatic Vertebrates. UC Press: Berkeley. 

Hildebrand, J.A. 2005. Impacts of anthropogenic sound, pp. 101-158. In: Richardson, W.J., 

C.R. Greene, Jr., C.I. Malme, and D.H. Thomson (eds.), Marine Mammals and Noise. San Diego: 

Academic Press. 

Holst, M., W.J. Richardson, W.R. Koski, M.A. Smultea, B. Haley, M.W. Fitzgerald, and M. Rawson. 

2007. Effects of large and small-source seismic surveys on marine mammals and sea turtles. 

American Geophysical Union, abstract #OS42A-01. Internet website: http://adsabs.harvard.edu/abs/

2006AGUSMOS42A..01H. Accessed August 5, 2011. 

Ketten, D.R., C. Merigo, E. Chiddick, and H. Krum. 1999. Acoustic fatheads: parallel evolution of 

underwater sound reception mechanisms in dolphins, seals, turtles, and sea birds. J. Acoust. Soc. 

Am. 105:1110. 

Lavender, A.L., S.M. Bartol, and I.K. Bartol. 2010. Hearing capabilities of loggerhead sea turtles 

(Caretta caretta) throughout ontogeny. Proceedings of the Second International Conference on the 

Effects of Noise on Aquatic Life, Cork, Ireland. 

Lavender, A.L., S.M. Bartol, and I.K. Bartol. 2011. A two-method approach for investigating the 

hearing capabilities of loggerhead sea turtles (Caretta caretta). Proceedings of 31st Annual 

Symposium on Sea Turtle Biology and Conservation, San Diego, CA. 

Lenhardt, M.L., R.C. Klinger, and J.A. Musick. 1985. Marine turtle middle-ear anatomy. J. Aud. Res. 

25(1):66-72. 

McCarthy, E. 2004. International Regulation of Underwater Sound: Establishing Rules and Standards to 

Address Ocean Noise Pollution. Kluwer Academic Publishers, Norwell, MA. 287 pp. 

McCauley, R.D., J. Fewtrell, A.J. Duncan, C. Jenner, M-N. Jenner, J.D. Penrose, R.I.T. Prince, 

A. Adhitya, J. Murdoch, and K. McCabe. 2000. Marine seismic surveys – a study of environmental 

implications. APPEA Journal 692-708. Internet website: http://www.anp.gov.br/meio/guias/sismica/

biblio/McCauleye2000.PDF. Accessed August 5, 2011. 

Moein, S.M. 1994. Auditory evoked potentials of the loggerhead sea turtle (Caretta caretta). Master’s 

thesis, College of William and Mary, Williamsburg, Virginia. Internet website: http://

el.erdc.usace.army.mil/tessp/pdfs/Auditory%20Evoked%20Potentials_Thesis.pdf. Accessed August 

5, 2011. 

Moein, S.E., J.A. Musick, J.A. Keinath, D.E. Barnard, M.L. Lenhardt, and R. George. 1995. Evaluation 

of seismic sources for repelling sea turtles from hopper dredges, pp. 90-93. In: L.Z. Hales (ed.), Sea 

Turtle Research Program: Summary Report. Technical Report CERC-95. 

Mrosovsky, N. 1972. S pectographs of the sounds of leatherback turtles. Herpetologica 29(3):256-258. 

Nunny, R., E. Graham, and S. Bass. 2008. Do sea turtles use acoustic cues when nesting? NOAA Tech. 

Mem. NMFS SEFSC No. 582:83. Internet website: http://www.nmfs.noaa.gov/pr/pdfs/species/

turtlesymposium2005.pdf. Accessed August 5, 2011. 

O’Hara, J. and J.R. Wilcox. 1990. Avoidance responses of loggerhead turtles, Caretta caretta, to low 

frequency sound. Copeia 2:564-567. 

Ridgway, S.H., E.G. Wever, J.G. McCormick, J. Palin, and J.H. Anderson. 1969. Hearing in the giant 

sea turtle, Chelonia mydas. Proc. Nat. Acad. Sci. 64:884-890. Internet website: http://

www.ncbi.nlm.nih.gov/pmc/articles/PMC223317/pdf/pnas00113-0080.pdf. Accessed August 5, 

2011. 

Samuel, Y., S.J. Morreale, C.H. Greene, and M.E. Richmond. 2005. Underwater, low-frequency noise in 

coastal sea turtle habitat. J. Acoust. Soc. Am. 117(3):1465-1472. 
Sea Turtle Hearing and Sensitivity to Acoustic Impacts I-7 

Warchol, M.E. 2011. Sensory regeneration in the vertebrate inner ear: Differences at the levels of cells 

and species. Hearing Research 273:72-79 

Weir, C.R. 2007. Observations of marine turtles in relation to seismic airgun sound off Angola. Marine 

Turtle Newsletter 116:17-20. Internet website: http://www.seaturtle.org/mtn/archives/mtn116/

mtn116p17.shtml. Accessed August 5, 2011. 

Wever, E.G. 1978. The reptile ear: Its structure and function. Princeton University Press, Princeton. 

Wever, E.G. and J.A. Vernon. 1956. The sensitivity of the turtle’s ear as shown by its electrical 

potentials. Proc. Nat. Acad. Sci. 42:213-220. Internet website: http://www.ncbi.nlm.nih.gov/pmc/

articles/PMC528254/pdf/pnas00707-0043.pdf. Accessed August 5, 2011. 

APPENDIX J 

 

FISH HEARING AND SENSITIVITY TO ACOUSTIC IMPACTS

Fish Hearing and Sensitivity to Acoustic Impacts J-iii 

TABLE OF CONTENTS 

Page 

1. INTRODUCTION ............................................................................................................................ J-1

1.1. What is Injury for Fishes?........................................................................................................ J-1

1.2. Fish........................................................................................................................................... J-1

1.3. Fish Bioacoustics – Overview.................................................................................................. J-2

1.4. Metrics of Sound Exposure......................................................................................................J-2

2. BACKGROUND ON FISH HEARING........................................................................................... J-3

2.1. Sound in Water ........................................................................................................................ J-3

2.2. Hearing Sensitivity................................................................................................................... J-3

2.3. Other Aspects of Fish Hearing................................................................................................. J-7

3. EFFECTS OF HUMAN-GENERATED SOUND ON FISHES – OVERVIEW ............................. J-8

4. EFFECTS OF ANTHROPOGENIC SOUNDS ON HEARING ...................................................... J-9

4.1. Auditory Masking .................................................................................................................... J-9

4.2. Temporary Threshold Shift......................................................................................................J-9

4.3. Effects of High Intensity Sources on Hearing........................................................................ J-10

5. EFFECTS OF HIGH INTENSITY SOURCES.............................................................................. J-11

5.1. Non-Auditory Physiological Effects of Exposure to Intense Sounds .................................... J-11

5.2. Auditory Effects of Exposure to Intense Sounds ................................................................... J-12

6. EFFECTS OF ANTHROPOGENIC SOUNDS ON BEHAVIOR ................................................. J-12

6.1. Fish Catch and Anthropogenic Sound.................................................................................... J-14

6.2. Other Behavioral Studies .......................................................................................................J-15

7. OTHER ISSUES WITH REGARD TO EFFECTS OF ANTHROPOGENIC SOUNDS .............. J-16

7.1. Stress...................................................................................................................................... J-16

7.2. Eggs and Larvae..................................................................................................................... J-16

7.3. Invertebrates........................................................................................................................... J-17

7.4. Vessel Noise and Fish............................................................................................................ J-18

8. GENERAL CONCLUSIONS – EFFECTS .................................................................................... J-18

8.1. Physiological Effects.............................................................................................................. J-19

8.2. Effects on Fish Behavior........................................................................................................ J-20

8.3. Increased Background Sound................................................................................................. J-20

9. CURRENT CRITERIA .................................................................................................................. J-20

10. REFERENCES CITED................................................................................................................... J-21

Fish Hearing and Sensitivity to Acoustic Impacts J-1

1. INTRODUCTION 

This report considers the effects of human-generated (anthropogenic) sound on fishes, with particular 

reference to seismic airguns and sonars. However, since there are few data on the effects of any 

anthropogenic sources on fishes, much of the discussion will be based upon a wider range of sound 

sources, with a goal of some extrapolation to help inform potential effects from airguns and sonars. 

Emphasis will be placed upon peer-reviewed studies in the scientific literature. However, gray literature 

reports of high scientific quality will be cited as appropriate. 

It should be noted that this review will not be comprehensive. Readers interested in more extensive 

analysis of the effects of anthropogenic sounds on animals are referred to Popper (2003), Hastings (2008), 

Popper and Hastings (2009a), and Slabbekoorn et al. (2010) for general reviews and to Popper and 

Hastings (2009b) and the papers in Popper and Hawkins (2011) for a more detailed overview. 

1.1. WHAT IS INJURY FOR FISHES? 

A fundamental issue of concern with regard to fishes is what constitutes “injury” in the sense of the 

marine mammal literature (see Southall et al. [2007]) and the Marine Mammal Protection Act. For 

marine mammals, permanent hearing loss (or permanent threshold shift [PTS]) is considered injury. But, 

as discussed below, PTS is not likely to occur in fishes, and all evidence for temporary hearing loss 

(or temporary threshold shift [TTS]) shows that fishes recover quickly from this loss. Thus, for the sake 

of this discussion, “injury” would not include effects on hearing. 

So, a question of importance is when “injury” starts in fishes and the nature of physiological effects 

that can lead to injury. In the very limited literature on interim criteria for regulation of exposure of fishes 

to pile driving sound (regulations have not be promulgated for other sound sources), the concern is for the 

onset of physiological effects, but this is not clearly defined. In a recent study by Halvorsen et al. 

(2011a,b) on effects of pile driving sounds on Chinook salmon (and similar studies by Casper et al., 

2011a on striped bass and tilapia), it has become clear that there are some effects that have the potential 

for impacting the survival of fishes (e.g., burst swim bladder, massive internal bleeding), whereas other 

effects have no more impact on survival than does a small cut on the arm of a human (e.g., external 

bleeding at the base of fins). 

Therefore, until a better definition of “injury” is available and agreed upon for fishes, an injury will 

be defined as an effect on the physiology of the animal that leads to immediate or potential death for the 

purposes of this report. In contrast, behavioral effects, such as moving from a site of feeding, would not 

be considered an injury. 

At the same time, it might ultimately be possible and worthwhile to attempt to define criteria for 

behavioral impacts. However, as discussed in the body of this report, there are no data currently available 

that provide guidance on this topic. 

1.2. FISH

The term “fish” generally refers to three groups of vertebrates: (a) the Agnatha or jawless 

vertebrates; (b) the cartilaginous fishes; and (c) the bony fishes (see Nelson [2006]). The Agnatha are a 

small group of very ancient vertebrates that primarily includes lamprey, and they will not be considered 

further. See Nelson (2006) for a complete review of fishes and their evolutionary relationships and 

www.fishbase.org for a listing of the more than 32,000 known living species. 

The cartilaginous fishes, or elasmobranchs, include sharks and rays and their relatives. Virtually 

nothing is known about effects of human-generated sound on cartilaginous fishes, but there is concern 

about potential effects since these animals are integral to the ecosystem in many parts of the marine 

environment (Casper et al., 2011b). 

Bony fishes include most of the species of aquatic vertebrates, including the majority of the species of 

fishes that are consumed by humans1

. Unless otherwise stated, the term “fishes” in this report will refer 

to bony fishes. By convention, the word “fish” refers to one or more members of the same species, 

whereas “fishes” refers to multiple species. 

 

1 E.g., tuna, salmon, cod, herring, pollack, and many others.
J-2 Atlantic G&G Programmatic EIS 

1.3. FISH BIOACOUSTICS – OVERVIEW

Sound plays a major role in the lives of all fishes (e.g., Zelick et al., 1999; Fay and Popper, 2000). 

This is particularly the case since sound travels much further in water than other potential signals, and it is 

not impeded by darkness, currents, or obstacles in the environment. Thus, fishes can glean a great deal of 

information about biotic (living) and abiotic (environmental) sources and get a good “image” of the 

environment to a very substantial distance from the animal (e.g., Fay and Popper, 2000; Popper et al., 

2003; Slabbekoorn et al., 2010). 

In addition to listening to the overall environment and being able to detect sounds of biological 

relevance (e.g., the presence of a reef, the sounds produced by swimming predators), many species of 

bony fishes (but not elasmobranchs) communicate with sounds and use sounds in a wide range of 

behaviors including, but not limited to, mating and territorial interactions (see Zelick et al. [1999] for 

review). Consequently, anything that impedes the ability of a fishes to hear biologically relevant sounds, 

such as those produced by anthropogenic sound sources, could interfere with the normal behaviors and 

even the survival of individuals, populations, or a species. Much more detailed discussions of all aspects 

of fish bioacoustics can be found in the papers in Webb et al. (2008) and in papers by Fay and 

Megela-Simmons (1999), Zelick et al. (1999), and Popper et al. (2003). A broad discussion of 

interactions of anthropogenic sounds and fishes can be found in Popper and Hastings (2009a,b) and in the 

papers in Popper and Hawkins (2011). 

1.4. METRICS OF SOUND EXPOSURE

Before discussing effects of anthropogenic sound on fishes, it is important to understand that, to date, 

it has not been possible to easily compare results from the studies with different anthropogenic sources. 

In part, this is because while different sources are reasonably similar in maximum intensity, they have 

different spectral characteristics and rise times. In particular, rise time, which is the time from the onset 

of the signal to when it reaches a high level, can impact effects. Signals with slow rise times will affect 

air bubbles in the body (e.g., swim bladder) slowly, and so the bubbles will change size slowly and let the 

surrounding tissues adjust to the changes. In contrast, a signal with a fast rise time will cause rapid 

changes of the air bubbles, and the walls of the expanding and contracting bubble will “knock into” the 

surrounding tissues, which are, in effect, rigid next to the moving bubble. This causes damage to the 

nearby tissues. An analogy might be the effect on a nail being pounded through hard wood by a weak 

versus strong hammer strike. 

The second issue in comparing results arises from the spectrum and time course of the signal and how 

these are described and calibrated. Until recently, most sound sources were described in terms of peak 

pressure and root-mean-square (rms) pressure. Peak pressure represents the maximum point of the energy 

in a signal whereas rms describes the average level of energy in the signal. The problem with both 

measures is that they do not give a good representation of the total energy in the signal over time – and it 

is this total energy that is likely to be the critical factor in determining potential effects on a receiver 

(Popper and Hastings, 2009b). 

In comparing sounds such as sonars, seismic airguns, and pile driving, there may be similarities in 

both peak and rms, but neither measure shows the actual differences in the total energy to which a 

receiver is exposed. More recently, investigators have started to use a third measure, the Sound Exposure 

Level (SEL). The SEL is the integration over time of the square of the acoustic pressure (Popper and 

Hastings, 2009b) and is an indication of the total acoustic energy received by an organism, representing 

the total energy in a signal over time – most often in one second of exposure (see Popper and Hastings 

[2009b] for discussion of SEL and how it is calculated). SEL allows for a comparison between signals 

since it provides a measure of all energy present in a signal, and it has, accordingly, been more and more 

accepted by investigators (e.g., Popper et al., 2005, 2007; Hastings et al., 2008; Hastings and 

Miskis-Olds, 2011; Halvorsen et al., 2011a,b). 

There are two uses of SEL. One is referred to as single-strike SEL (SELss), and the other is 

cumulative SEL (SELcum)

2

. The SELss is the energy in a single signal, such as a single pile driving strike 

 

2

 Note, abbreviations for single strike and cumulative SEL has not been standardized and is adopted here from Halvorsen et al. 

(2011b). 
Fish Hearing and Sensitivity to Acoustic Impacts J-3

or a single blast from a seismic airgun. The SELcum is the energy in all of the signals presented, such as in 

all of the strikes during a pile driving operation or seismic study3

. 

2. BACKGROUND ON FISH HEARING 

2.1. SOUND IN WATER

The basic physical principles of sound in water are the same as sound in air. Any sound source 

produces both pressure waves and actual motion of the medium particles. However, whereas the actual 

particle motion in air is inconsequential even a few centimeters from a sound source, particle motion 

travels (propagates) much further in water because of the density of water compared to air4

. For a more 

extensive discussion of underwater acoustics, see Urick (1983) and Rogers and Cox (1988). 

All fishes, including elasmobranchs, detect particle motion since it directly stimulates the inner ear 

(Popper et al., 2003). Bony fishes with an air bubble (most often the swim bladder) are also likely to 

detect pressure signals that are reradiated to the inner ear as particle motion. Species detecting pressure 

hear a wider range of frequencies and sounds of lower intensity than fishes without an air bubble since the 

bubble re-radiates the received signal, which is then detectable by the ear as a secondary sound source 

(Popper et al., 2003; Popper and Fay, 2010). 

Exactly how well fishes with an air bubble hear depends on the relative position of the air bubble and 

ear. When the two structures are close together or when there is some kind of physical coupling between 

them the bandwidth of hearing and sensitivity is greater than it is in fishes where the air bubble and ear 

are further apart or not coupled. In the latter case, the signal that is re-radiated from the air bubble 

attenuates (decreases) over the distance between the structures, whereas in the other species the proximity 

of the structures, or the coupling, ensures that most of the energy re-radiated from the bubble gets to the 

ear5

. 

2.2. HEARING SENSITIVITY

Basic data on hearing provides information about the range of frequencies that a fish can detect and 

the lowest sound level that an animal is able to detect at a particular frequency (Figure J-1). This level is 

often called the “threshold.”6

 Sounds that are above threshold are detectable by fishes. 

Hearing thresholds have been determined for perhaps 100 species (Figure J-1) (for data on hearing 

thresholds, see Fay [1988], Popper et al. [2003], Ladich and Popper [2004], Nedwell et al. [2004], 

Ramcharitar et al. [2006], and Popper and Schilt [2008]). These data demonstrate that, with few 

exceptions, fishes cannot hear sounds above about 3-4 kHz, and the majority of species are only able to 

detect sounds to 1 kHz or below7

. There have also been studies on a few species of cartilaginous fishes, 

with results suggesting that they detect sounds to no more than 600 or 800 Hz (e.g., Myrberg et al., 1976; 

Myrberg, 2001; Casper et al., 2003; Casper and Mann, 2006). 

 

3

 As discussed below, there is some indication that if there is sufficient time (e.g., more than 12 hrs) between an accumulation

period for SEL, then the accumulation for the next exposure period starts again at 0. 4

 The wavelength of a sound in water is about 1,500 m/sec (it varies depending on salinity, depth, temperature, etc.). The 

wavelength is defined as 1500/frequency which means for a 500 Hz signal the wavelength is 3 m. For a 100 Hz signal the 

wavelength is 15 m and the near field transition point would be 15/6.28 = ~2.8 m. 5

 Until recently the literature talked about hearing “generalists” and “specialists.” However, these terms are no longer in use. 

See Popper and Fay (2010) for explanation and discussion. 6

 Very often, for fish, hearing thresholds are the lowest levels at which sound is detected 50% of the time. In other words, 

whereas a fish will detect a particular signal 50% of the time, it will not detect the same signal 50% of the time. Variation in 

threshold is well known and reflects momentary changes in the detecting structure, in the motivation of the animal, and 

innumerable other factors. 7

 The lowest detectable frequency is often hard to determine since the limiting factor in experiments trying to measure this is 

often the equipment. In many cases, the equipment does not work well at frequencies below 50-100 Hz, making it hard to 

determine if fishes can detect lower frequencies. However, recent studies using specialized equipment have demonstrated that 

some species can detect sounds below 50 Hz (called infrasound), but it is still not clear if this is done by the ear or by the lateral 

line (Karlsen, 1992; Knudsen et al., 1994). 
J-4 Atlantic G&G Programmatic EIS 

Figure J-1. Hearing Curves (Audiograms) for Select Bony Fishes (see Fay [1988], Nedwell et al. [2004], 

and Ramcharitar [2006] for data). Each data point indicates the lowest sound level the 

species could detect at a particular frequency (see text for caveats on data). Group number 

given in the legend refers to the discussion within the text. Data for American shad are 

truncated at 50 kHz to keep the size of the graph reasonable, but it should be noted that this 

species can hear sounds to at least 180 kHz (Mann et al., 1997). 

The data available, while very limited, suggest that the majority of marine species do not have 

specializations to enhance hearing and probably rely on both particle motion and sound pressure for 

hearing. Most importantly, it should be noted that hearing capabilities vary considerably between 

different bony fish species (Figure J-1; Table J-1), and there is no clear correlation between hearing 

capability and environment. There is also broad variability in hearing capabilities within a single fish 

group. As just one example, there is broad diversity in hearing capabilities and hearing structures within 

the family Sciaenidae (drumfish, weakfish, croakers) (Figure J-1; data reviewed in Ramcharitar et al. 

[2006]; see also Popper and Schilt [2008]). 
Fish Hearing and Sensitivity to Acoustic Impacts J-5

Table J-1 

 

Marine Fish Hearing Sensitivity 

Family Common 

Name of Taxa 

Highest 

Frequency 

Detected 

(Hz)a

Hearing 

Categoryb Reference Notes 

Asceripensidae Sturgeon 800 2 

Lovell, et al., 

2005; Meyer et al., 

2010 

Several different species tested. 

Relatively poor sensitivity 

Anguillidae Eels 300 2 Jerkø et al., 1989 Poor sensitivity 

Batrachoididae Toadfishes 400 2 

Fish and Offutt, 

1972; Vasconcelos 

and Ladich, 2008 

Shad, 

menhden >120,000 4 Mann et al., 1997, 2001 

Ultrasound detecting, but 

sensitivity relatively poor 

Clupeidae Anchovy, 

sardines, 

herrings 

4,000 4 Mann et al., 2001 

Not detect ultrasound, and 

relativley poor sensitivitiy 

Chondrichthyes 

[Class] 

Rays, sharks, 

skates 1,000 1 Casper et al., 2003 Low-frequency hearing, not very sensitive to sound 

Atlantic cod, 

haddock, 

pollack, hake 

500 2 

Chapman and 

Hawkins, 1973; 

Sand and Karlsen, 

1986 

Probably detect infrasound 

(below 40 Hz). 

Best hearing 100-300 Hz 

Gadidae 

Grenadiers 3? Deng et al., 2011 

Deep sea, highly specialized ear 

structures suggesting good 

hearing, but no measures of 

hearing 

Gobidae Gobies 400 1 or 2 Lu and Xu, 2009 

Labridae Wrasses 1,300 2 Tavolga and 

Wodinksy, 1963 

Lutjanidae Snappers 1,000 2 Tavolga and 

Wodinksy, 1963 

Malacanthidae Tilefish 2 NA No data 

Moronidae Striped bass 1,000 2 Ramcharitar 

unpublished 

Pomacentridae Damselfish 1,500 – 

2,000 2 Myrberg and Spires, 1980 

Pomadasyidae Grunts 1,000 2 Tavolga and 

Wodinsky, 1963 

Polyprionidae Wreckfish 2 NA No data 

Drums, 

weakfish, 

croakers 

1,000 2 Ramcharitar et al., 

2006 

Hear poorly 

Sciaenidae 

Silver perch 3,000 3 Ramcharitar et al., 

2004, 2006 

Serranidae Groupers 2 NA No data 

Yellowfin tuna 1,100 2 Iversen, 1967 With swim bladder 

Scombridae Tuna 1,000 1 Iversen, 1969 Without swim bladder 

Bluefin tuna 1,000 2 Song et al., 2006 Based only on ear anatomy a

 Lower frequency of hearing is not given since, in most studies, the lower end of the hearing bandwidth is more a function of the 

equipment used than determination of actual lowest hearing threshold. In all cases, fish hear below 100 Hz, and there are some

species studied, such as Atlantic cod, Atlantic salmon, and plaice, where fish have been shown to detect infrasound, or sounds 

below 40 Hz. b

 See text for explanation. 

Notes: See text for important caveats about the data. For a number of additional species, hearing capabilities can only be 

surmised from morphological data. These data are shown shaded in gray 

Sources: Data compiled from reviews in Fay (1988) and Nedwell et al. (2004). Updated names: www.fishbase.org. 
J-6 Atlantic G&G Programmatic EIS 

Table J-1 and Figure J-1 provide data on a number of fish groups of potential interest for this report. 

The data in Table J-1 are presented in terms of fish taxa (family level) since data are often not available 

for specific species of interest. However, it is possible to extrapolate between broad groups of fishes in 

most cases. Where that is not the case, as in the sciaenids (reviewed in Ramcharitar et al., 2006), several 

different sets of data are shown. Moreover, this is also done when species within a group differ 

substantially in hearing structures. Thus, in the case of tuna, there are some species with a swim bladder 

(involved in pressure detection) and others that do not have a swim bladder (Iversen, 1967, 1969). 

Indeed, in the case of tuna, while the hearing range of the species with and without swim bladders is quite 

similar, it is likely that the sensitivity is poorer in the species without this structure. 

It should also be noted that Table J-1 only gives the likely highest frequency of hearing for a fish and 

leaves out the low frequency end of the hearing bandwidth. This is done because what is known about 

low frequency hearing is often a function of the equipment used in the study and not what the fish 

actually hears. Thus, if the sound source used to study hearing is only good to 100 Hz, then that might be 

the lowest frequency that investigators report. As a consequence, the low frequency range, with a few 

exceptions, must be viewed with caution, even as presented in Figure J-1. However, it is accurate to 

state that most, if not all, fishes can detect sounds to below 100 Hz and likely to below 50 Hz. 

Another point to note is that Table J-1 does not show hearing sensitivity, and the data in Figure J-1

are not presented as thresholds but as relative levels of hearing within a single fish’s hearing capabilities. 

Thus, Table J-1 does not show the lowest sound levels that a fish can hear, nor does it indicate at what 

frequency best hearing occurs. The table is presented as it is because there is wide variation in data even 

for a single species (e.g., see Fay [1988] for a demonstration of different data on hearing for goldfish). 

The variation is likely a result of experimental design. It is often the case that the investigators did not 

use the right stimulus parameter (pressure or particle motion) to test a species. Thus, investigators have 

often presented hearing sensitivity data for fishes in terms of pressure sensitivity, even when the fish is 

likely not to detect sound pressure as it primarily detects particle motion (something that, until recently, 

has been very hard to measure). 

With these caveats, it is possible to make some useful generalizations with regard to fish hearing that 

remove some of the “variability” in the data and help focus understanding of fish hearing capabilities. 

Such generalizations also make it possible to “predict” hearing range and sensitivity of some species for 

which there are data on the structure of the ear and auditory system but no hearing data. Indeed, such is 

the case for bluefin tuna, where, despite lack of hearing data, it is possible to predict that the hearing 

range for this species is similar to that of other tuna based on similarities in ear structure (Song et al., 

2006). Similarly, morphological data on the ears of deep-sea grenadiers leads to the suggestion that these 

species have inner ear specializations that are often associated with fishes that hear to 2,500-4,000 Hz and 

have good hearing sensitivity (Deng et al., 2011); a similar observation has been made for myctophids 

(Popper, 1980). 

Based on this kind of analysis, it is possible to “categorize” fish groups as to their hearing 

capabilities. This is presented in Table J-1 where a column provides the categories of each species 

represented, which are defined as follows: 

 Group 1: Fishes that do not have a swim bladder (e.g., Plaice in Figure J-1). These 

fishes are likely to use only particle motion for sound detection. The highest 

frequency of hearing is likely to be no greater than 400 Hz, with poor sensitivity 

compared to fishes with a swim bladder. Fishes within this group would include 

flatfish, some gobies, some tunas, and all sharks and rays (and relatives). 

 Group 2: Fishes that detect sounds from below 50 Hz to perhaps 800-1,000 Hz 

(though several probably only detect sounds to 600-800 Hz). These fishes have a 

swim bladder but no known structures in the auditory system that would enhance 

hearing, and sensitivity (lowest sound detectable at any frequency) is not very great. 

Sounds would have to be more intense to be detected when compared to fishes in 

Group 3. These species detect both particle motion and pressure, and the differences 

between species are related to how well the species can use the pressure signal. A 

wide range of species fall into this category, including tuna with swim bladders, 

sturgeons, salmonids, etc. 
Fish Hearing and Sensitivity to Acoustic Impacts J-7

 Group 3: Fishes that have some kind of structure that mechanically couples the inner 

ear to the swim bladder (or other gas bubble), thereby resulting in detection of a 

wider bandwidth of sounds and lower intensities than fishes in other groups 

(e.g., silver perch in Figure J-1). These fishes detect sounds to 3,000 Hz or more, 

and their hearing sensitivity, which is pressure driven, is better than in fishes of 

Groups 1 and 2. There are not many marine species known to fit within Group 3, but 

this group may include some species of sciaenids (Ramcharitar et al., 2006). It is 

also possible that a number of deep-sea species fall within this category, but that is 

only predicted based on morphology of the auditory system (e.g., Popper, 1980; 

Deng et al., 2011). Other members of this group would include all of the Otophysan 

fishes, though few of these species other than catfishes are found in marine waters. 

 Group 4: All of these fishes are members of the herring family and relatives 

(Clupeiformes). Their hearing below 1,000 Hz is generally similar to fishes in 

Group 1, but their hearing range extends to at least 4,000 Hz (e.g., sardine in 

Figure J-1), and some species (e.g., American shad) are able to detect sounds to over 

180 kHz (Mann et al., 2001). 

2.3. OTHER ASPECTS OF FISH HEARING

Besides being able to detect sounds, a critical role for hearing is to be able to discriminate between 

different sounds (e.g., frequency and intensity), detect biologically relevant sounds in the presence of 

background noises (called maskers, see below), and determine the direction and location of a sound 

source in the space around the animal. While actual data are available on these tasks for only a few fish 

species, all species are likely to have similar capabilities (reviewed in Fay and Megela-Simmons, 1999; 

Popper et al., 2003; Fay, 2005). 

Only a few points about the hearing structure in fishes is critical for this report, and readers interested 

in more detail can find reviews by Popper et al. (2003) and Popper and Schilt (2008). The fundamental 

structure for hearing by fishes is the inner ear. This is, in many ways, very similar in structure and 

function to the ear found in all other vertebrates. The inner ear has three otolith organs – the saccule, 

lagena, and utricle – each containing a dense structure called an otolith. The otolith lies in close 

proximity to a sensory surface called the sensory epithelium. Each epithelium contains sensory hair cells 

that are very similar to those found in the mammalian ear. On their top surfaces, sensory hair cells have 

hair-like projections, called cilia, that are bent when the epithelium and otolith move out of phase from 

one another – something that takes place when sound stimulates the ear. The sensory cells respond 

physiologically to the bending of the cilia and send signals on to the brain via the eighth cranial nerve – 

the same nerve involved in hearing in humans. 

Germane to issues of effects of loud sounds on fishes is that the sensory hair cells in fishes, as in 

mammals (including humans), can be damaged or actually killed by exposure to very loud sounds 

(Le Prell et al., 2011). However, whereas in humans once sensory cells die they are not replaced, 

resulting in deafness, fishes are able to repair and replace cells that die (e.g., Lombarte et al., 1993; Smith 

et al., 2006). Moreover, whereas in humans the ear has its full complement of sensory hair cells at birth, 

fishes continue to produce (proliferate) sensory hair cells for much of their lives, which results in fishes 

having more and more sensory hair cells as they age (Popper and Hoxter, 1984; Lombarte and Popper, 

1994). Indeed, large Mediterranean hake (Merluccius merluccius) have been shown to have a million or 

more sensory hair cells in a single saccule (Lombarte and Popper, 1994), as compared to humans which 

have, at birth, no more than 20,000 sensory cells in the auditory part of the ear. 

Because fishes have the ability to repair damaged sensory hair cells and continuously add to their 

number, fishes are not likely to ever become deaf permanently. As discussed below, there is some chance 

of temporary hearing loss, but this is quickly repaired (Smith et al., 2006), and there is no evidence in 

fishes for permanent hearing loss. 
J-8 Atlantic G&G Programmatic EIS 

3. EFFECTS OF HUMAN-GENERATED SOUND ON FISHES – 

OVERVIEW 

There is a wide range of potential outcomes of exposing fishes to sound, from no effect to immediate 

death. Data on effects of sounds are limited, and broad extrapolations about effects on different species 

(or on the same species at different ages or sizes) is not yet possible (see discussion in Popper and 

Hastings [2009b] and Popper and Hawkins [2011]). Moreover, while there are some (albeit limited) data 

on effects on physiology, far less is known about effects on behavior. 

The actual effects will vary based on a large number of factors. In particular, other than for 

physiological damage, which does not depend on hearing per se, the likelihood of TTS, masking, and/or 

behavioral change will depend on whether the fish hears the sound. Figure J-2 illustrates the idea that 

there is a likelihood of any number of different potential effects close to the source and that the range of 

potential effects declines with increased distance from the source. 

The actual effects are also likely to depend on the nature of the sound source itself. One may divide 

sounds into two very overlapping “classes”: intermittent (or acute) and long-term (or chronic) (Popper 

and Løkkeborg, 2008). Intermittent sounds usually are of short duration and high intensity, and they are 

only present in a particular area for a short period of time. These include sounds produced by seismic 

airguns, sonars, and similar sources. Pile driving would also fit into this category, although it may last for 

hours, days, or even weeks. But, ultimately, pile driving ends. Loud intermittent sounds have the 

potential to cause death and physiological effects if the animal is close to the source. They could also 

produce hearing loss, masking, and behavioral effects to distances beyond those that would result in death 

or damage (Figure J-2). 

Long-term (chronic) sources are generally lower in intensity than acute signals, may extend over a 

broad area, and, in general, raise the ambient noise level from a few to many decibels. In essence, chronic 

noise sources raise the overall background ambient level of the environment similar to what might be 

encountered when new machinery is added to a factory. In the case of the aquatic environment, perhaps 

the most dominant changes in the chronic noise environment come from boats which, is more likely to 

occur in a harbor, major shipping lanes, and similar areas. Long-term rises in sound level are not likely to 

result in death or physiological effects (though it is possible that there may be long-term changes in stress 

levels and immune response), but they could also produce hearing loss, masking, and/or behavioral 

effects (Figure J-2). 

Figure J-2. Relationship between Noise Levels, Distance, and Potential Effects. (Note that close to the 

source, there is a range of potential effects, but as the distance from the source increases and 

sound levels get lower, the likelihood of some potential effects decreases. The actual effects 

will vary depending on the source. If the source is very intensive, then mortality may occur. 

But, if the source is less intensive, mortality and physiological effects may mot be an issue. At 

the lowest source levels, such as with increases in ambient sounds, behavioral responses and/or 

masking may be the only issues of concern.) 
Fish Hearing and Sensitivity to Acoustic Impacts J-9

4. EFFECTS OF ANTHROPOGENIC SOUNDS ON HEARING 

While there are few data on behavioral effects of sounds on fishes in the wild (Section 6.0), there are 

substantial data on effects of such sounds on the ability of fishes to hear. If hearing is impaired, even 

temporarily, a fish may not be able to find food or detect predators as successfully. Such impairment may 

be by auditory masking or temporary loss of hearing. 

4.1. AUDITORY MASKING

Masking is a key issue for potential effects of human-generated sound on all vertebrates, including 

fishes (reviewed in Fay and Megela-Simmons, 1999; Popper et al., 2003). Masking occurs when there are 

sounds in the environment that are in the same frequency range as the sound of biological relevance to the 

animal and/or within the hearing range of the fishes. Thus, if a fish has a particular threshold for a 

biologically relevant sound in a quiet environment and a background noise in the same frequency range is 

introduced, this will decrease the ability of the fish to detect the biologically relevant signal. In effect, the 

threshold for the biologically relevant signal will become poorer. Thus, if background noise increases, it 

may be harder for a fish to detect the biologically relevant sounds that it needs to survive. Specifically, if 

the ambient noise (or masker) is raised by 10 dB, the threshold of the fish will increase by about 10 dB in 

the frequency range of the masker. 

The actual concern with regard to masking is that fishes will not be able to hear sounds of biological 

relevance as well as they would without the masking sound. Thus, if a fish uses sounds to detect 

predators, the presence of the increased ambient sound would keep the fish from hearing the predator 

until it was much closer. Similarly, if male fishes use sounds to attract females, as occurs in toadfish 

(reviewed in Zelick et al., 1999), sciaenids (reviewed in Ramcharitar et al., 2006), and many other 

species, the female would have to be much closer to the males before they could hear the sound. In other 

words, the effectiveness of a male’s call would decline in the presence of masking sounds since the 

females would be less likely to detect the sounds unless they are closer to the source (where the source is 

louder in the presence of the masker). Indeed, this effect is well known and has been described for a wide 

range of other vertebrates, including birds and amphibians (reviewed in Slabbekoorn et al., 2010). 

More recently, it has been suggested that at least some larval fishes find the reefs upon which they 

will settle using sounds from the reef (e.g., Leis et al., 2003; Wright et al., 2005). These studies have 

suggested that if there is an increase in ambient (masking) noise, the larval fish would be less likely to 

hear the sounds of the reef and, thus, less likely find a place to settle. The reef sounds could be produced 

by a variety of sources, including snapping shrimp, water moving over reefs, other fishes, etc. and would 

be subject to masking by anthropogenic sounds within the hearing range of fishes. Clearly, if this 

observation is correct, then the presence of masking sounds could have a significant impact on long-term 

survival of populations of reef fishes. 

4.2. TEMPORARY THRESHOLD SHIFT

A second concern is that exposure to sounds can result in a temporary loss of hearing sensitivity, or 

TTS. Temporary threshold shift recovers after some period of time following the termination of the noise 

and results from temporary, but recoverable, damage to the sensory cells of the inner ear that are involved 

with for hearing (Smith et al., 2006). Permanent hearing loss (i.e., PTS), resulting from exposure to very 

loud sounds, occurs in humans and other mammals. Permanent threshold shift is not, however, known to 

occur in fishes, since unlike mammals, they can repair and regenerate the sensory cells of the ear that are 

damaged (e.g., Lombarte et al., 1993; Smith et al., 2006)8

. 

Data on TTS in fishes are reviewed in Popper and Hastings (2009b) and are only briefly summarized 

here. The data suggest that TTS occurs after long-term exposure to sounds that are as high as 

170-180 dB re 1 μPa (rms), but only in species that have specializations that result in their having 

relatively wide hearing bandwidths (to over 2 kHz) and lower hearing thresholds than fishes without 

specializations. For example, TTS of 10-20 dB has been demonstrated in goldfish (Carassius auratus) 

and lined Raphael catfish (Platydoras costatus) (e.g., Scholik and Yan, 2002; Smith et al., 2004a, 2006; 

 

8

 Interesting, the sensory cells in the mammalian and fish ear responsible for hearing are the same. The difference between 

fishes and mammals is that fishes retain a regenerative mechanism in the ear for when cells are lost, whereas no such capacity 

is found in mammals. 
J-10 Atlantic G&G Programmatic EIS 

Wysocki and Ladich, 2005), but little or no TTS has been found in fishes such as cichlids, sunfishes, and 

perch (e.g., Scholik and Yan, 2001; Amoser and Ladich, 2003; Smith et al., 2004a,b; Wysocki and 

Ladich, 2005). Moreover, studies of the effects of exposure to 150 dB re 1 μPa (rms, received level) for 9 

months showed no effect on hearing or on survival and growth of young rainbow trout (Oncorhynchus 

mykiss) (Wysocki et al., 2007). Significantly, in those species where TTS was found, hearing returned to 

normal starting well within 24 hrs after the end of exposure (e.g., Smith et al., 2004b, 2006). 

While TTS is not as likely to be particularly irrelevant with regard to repetitive sound sources, 

concerns have still arisen that fishes may temporarily have impaired hearing as a result of exposure to 

loud sounds (e.g., Popper et al., 2005, 2007; reviewed in Popper and Hastings, 2009b). Several studies 

show varying results, but overall, if TTS occurs as a result of exposure to loud sounds, it is not 

necessarily very great and recovery seems to be within 24 hrs in most cases (Popper et al., 2005, 2007; 

Hastings et al., 2008; Hastings and Miskis-Olds, 2011). 

The potential effects of TTS are similar to those of masking (Section 4.1). If the hearing ability of an 

affected fish decreases, then the likelihood of detecting predators, prey, or mates (or a reef) decline, thus 

decreasing the potential fitness of the receiver until normal hearing returns. 

4.3. EFFECTS OF HIGH INTENSITY SOURCES ON HEARING

Several studies have examined the effects of very high intensity sources on hearing and demonstrate 

little or no effect on a diverse group of species. Popper et al. (2005) and Song et al. (2008) examined the 

effects of exposure to a seismic airgun array on three species of fishes found in the Mackenzie River 

Delta near Inuvik, Northwest Territories, Canada. One species, the lake chub (Couesius plumbeus), has 

hearing specializations, whereas the northern pike (Esox lucius) and the broad whitefish (Coregonus 

nasus) (a salmonid) do not. Fishes were exposed to 5 or 20 shots from a 730-in3

 (12,000 cc) calibrated 

airgun array. And unlike earlier studies, the received exposure levels were not only determined for rms 

sound pressure level, but also for peak sound levels and SELs (e.g., average mean peak SPL 

207 dB re 1 μPa RL; mean rms sound level 197 dB e 1 μPa RL; mean SEL 177 dB re 1 μPa2

s). 

For both the 5 and 20 airgun shots, the results showed a temporary hearing loss for both lake chub 

and northern pike but not for broad whitefish. Hearing loss was on the order of 20-25 dB at some 

frequencies for both the northern pike and lake chub; full hearing recovery occurred within 18 hrs after 

sound exposure. 

Popper et al. (2007) studied the effect of the Surveillance Towed Array Sensor System (SURTASS) 

low-frequency active (LFA) sonar on hearing, the structure of the ear, and select non-auditory systems in 

the rainbow trout and channel catfish (Ictalurus punctatus) (also Halvorsen et al., 2006). Fishes were 

exposed to LFA sonar for 324 or 648 seconds, an exposure duration that is far greater than any fishes in 

the wild would get since, in the wild, the sound source is on a vessel moving past the far slower 

swimming fishes. The maximum received level was approximately 193 dB re 1 μPa at 196 Hz. Analysis 

of hearing showed that channel catfish and some specimens of rainbow trout showed 10-20 dB of hearing 

loss immediately after exposure to the LFA sonar when compared to baseline and control animals; 

however, another group of rainbow trout showed no hearing loss. Recovery in trout took at least 48 hrs, 

and channel catfish recovered with 24 hrs. Similar studies on several other species, including hybrid 

sunfish and black perch, showed no TTS to the same signals (Halvorsen et al., 2006). 

Finally, Hastings et al. (2008) studied TTS in Indian Ocean reef fishes during a seismic survey with a 

full airgun array. They found no hearing loss following sound exposures up to 190 dB re 1 μPa2

-s 

cumulative SEL in a species that hears well, in the pinecone soldierfish (Myripristis murdjan), and in 

three species that do not have hearing specializations: the blue green damselfish (Chromis viridis), sabre 

squirrelfish (Sargocentron spiniferum), and bluestripe seaperch (Lutjanus kasmira). 

In summary, it is clear that if hearing loss occurs after exposure to intense sounds (and it does not 

always occur), it primarily shows up in fishes with hearing specializations and is not permanent (i.e., there 

is full recovery). More importantly, TTS is less likely to show up in fishes without hearing 

specializations. The only time that TTS has been documented as a response to high intensity sources has 

been when the exposure duration has substantially exceeded the amount of time that an animal would 

normally be exposed to such sounds in the wild (Popper et al., 2007). 
Fish Hearing and Sensitivity to Acoustic Impacts J-11

5. EFFECTS OF HIGH INTENSITY SOURCES 

Intensive sources are generally short (measured in parts of a second to several seconds) and are highly 

intensive at the source (attenuation follows normal attenuation characteristics of sound in water). Also, 

exposure time to the sound for an animal may be rather short. For example, a fish exposed to high 

intensity sonar may only hear a few sonar sounds since the source, on a boat, is moving. In the case of 

seismic devices, the source is constantly moving, although the sounds may increase the overall ambient 

noise for the duration of a 3D seismic study. Sounds from pile driving may last for as long as the pile 

driving operation, but there frequently are periods of pile driving followed by longer periods of silence as 

new piles are added, hammers moved or repaired, etc. 

The concerns associated with intensive sources range from immediate mortality to delayed mortality 

to behavioral effects (Figure J-2). Behavioral effects are varied and less likely to involve masking or 

TTS, as found in long-term exposures, because of the short periods of the intense sounds. However, there 

are concerns, as discussed below, that an extended seismic survey could result in fishes leaving their 

feeding or spawning areas for extended periods of time, or even permanently, which could impact 

survival of populations as well as catchability for fishers (e.g., Engås et al., 1996; Slotte et al., 2004; 

Løkkeborg et al., 2011). 

At the same time, while much concern about intensive sources rests on immediate mortality, the 

limited data suggest that the circumstances under which immediate mortality occurs are very limited. 

Indeed, there are no data to suggest mortality associated with high intensity sources other than pile 

driving9

. 

The only data on mortality associated with sound (as compared to explosives) come from driving very 

large piles. For example, the California Department of Transportation (Caltrans, 2001) showed some 

mortality for several different species of wild fishes exposed to driving of steel pipe piles 2.4 m (8 ft) in 

diameter. However, no mortality seems to occur at distances of more than approximately 10 m (32.8 ft) 

from the source. 

5.1. NON-AUDITORY PHYSIOLOGICAL EFFECTS OF EXPOSURE TO INTENSE 

SOUNDS

Non-auditory physiological effects from exposure to intense sounds generally result from rapid and 

substantial expansion and contraction of the air bubble walls within fishes (such as the swim bladder or 

air bubbles in the blood) that strike against nearby tissues or from air bubbles within the blood bursting or 

expanding and damaging tissues (Stephenson et al., 2010). The actual nature of non-auditory 

physiological effects may range from a very small amount of external bleeding to small internal bleeding 

to substantial hemorrhage of tissues (such as kidney or liver) to rupture of the swim bladder (see 

Stephenson et al. [2010] and Halvorsen et al. [2011a,b] for a discussion of the range of potential effects). 

There are several potential (and overlapping) consequences of non-auditory physiological effects. 

One possibility is that the effects heal, and there is no lasting consequence. Alternatively, even if the 

physiological effect has no direct consequences per se, it is possible that it leads to temporary decreased 

fitness of the animal until the damage is healed. This could result in the animal being subject to 

predation, less able to find food, or other consequences that result in death. 

Secondly, the effect could result in delayed mortality from events such as continuous bleeding or 

disruption of tissues (e.g., spleen or liver). Or, the tissue damage itself may not be life threatening, but it 

may become infected and potentially result in death. 

There are few quantified and reliable data on effects of exposure to high intensity sound on body 

tissues. There are a number of studies showing no tissue damage as a result of exposure of several 

different species to sonar (Kane et al., 2010), seismic devices (Song et al., 2008), and pile driving 

(Caltrans, 2010a,b). However, in each of these studies, the swim bladder in the fishes may not have been 

filled with air, and this could have resulted in less likelihood of damage as compared to situations where 

the swim bladder is filled to its normal density of air (Halvorsen et al., 2011a,b). 

The only quantifiable study documenting a range of physiological effects on fishes comes from 

exposure of Chinook salmon to 960 or 1,920 strikes of simulated pile driving sounds (Halvorsen et al., 

 

9

 Note, there is mortality associated with explosive devices, but this is outside the purview of this appendix. A discussion of the 

effects of explosives can be found in Hastings and Popper (2005) and Popper and Hastings (2009b). 
J-12 Atlantic G&G Programmatic EIS 

2011a,b; Casper et al., 2011a). This study demonstrates that effects are graded, with what is likely 

to be minimal peripheral bleeding at the lowest (but still very intense) sound exposures 

(210 dB re 1 μPa2

·s SELcum) to significant bleeding and tissue rupture at the very highest levels presented 

in the study (219 dB re 1 μPa2

·s SELcum). Importantly, fish held for a period of time post-exposure 

showed complete recovery from most of the effects, although the investigators are very careful to point 

out that recovery took place in a lab tank where fish with slightly lowered fitness would not be subject to 

predation or disease as may happen in the wild (Casper et al., 2011a). 

Indeed, the overall impact on fishes in an ecosystem is low, as only a very small fraction of the fish 

population will likely be close enough to an intense source to be subject to immediate mortality. The 

open issues may be (a) injury that can lead to delayed mortality and (b) behavioral effects that lower 

fitness (e.g., move from migratory routes, leave food sites, and masking of biologically important 

sounds). 

5.2. AUDITORY EFFECTS OF EXPOSURE TO INTENSE SOUNDS

Several studies have examined effects of high intensity sounds on the ear. While there was no effect 

on ear tissue in either the SURTASS LFA study (Popper et al., 2007) or in the study of effects of seismic 

airguns on hearing (Popper et al., 2005; Song et al., 2008), three earlier studies suggested that there may 

be some loss of sensory hair cells resulting from exposure to high intensity sources. However, none of 

these studies concurrently investigated effects on hearing. Enger (1981) showed some loss of sensory 

cells after exposure to pure tones in the Atlantic cod (Gadus morhua). A similar result was shown for the 

lagena of the oscar (Astronotus oscellatus), a cichlid fish, after an hour of continuous exposure (Hastings 

et al., 1996). In neither study was the hair cell loss more than a relatively small percentage of the total 

sensory hair cells in the hearing organs. And, in neither case was the sound anything like the high 

intensity sources of concern today. 

Most recently, McCauley et al. (2003) showed loss of a small percentage of sensory hair cells in the 

saccule (the only end organ studied) of the pink snapper (Pagrus auratus), and this loss continued to 

increase (but never to become a major proportion of sensory cells) for up to at least 53 days 

post-exposure. This hair cell loss or the ones in the Atlantic cod or oscar would not necessarily have 

resulted in hearing loss since fishes have tens or even hundreds of thousands of sensory hair cells in each 

otolithic organ (Popper and Hoxter, 1984; Lombarte and Popper, 1994), and only a small portion were 

affected by the sound. The question remains as to why McCauley et al. (2003) found damage to sensory 

hair cells while Popper et al. (2005) did not. The difference in results may very well be associated with 

differences in species, precise sound source, spectrum of the sound, and sound propagation effects. For 

example, the Popper et al. (2005) study was in relatively shallow water with poor low-frequency 

propagation, therefore, the spectrum of sound is likely to have been very different than in the McCauley 

et al. (2003) study (Hastings, 2009). 

One question that arises in the McCauley study is the continued damage to sensory cells after 53 days 

and whether this would indicate that there was permanent hair cell damage and hearing loss. Since the 

tissue sampled at each time interval in this study were from different fish, it is impossible to know if the 

dead cells on Day 53 had been replaced by newly formed cells and what was seen as damage was scar 

tissue or if the cells that died post-exposure were not replaced. However, based on the considerable data 

demonstrating hair cell replacement and addition in many fish species, it is likely that even if the cells that 

were damaged did not get replaced, the high rate of sensory cell proliferation in fishes would have 

compensated for the small number of lost hair cells (e.g., Corwin, 1981; Popper and Hoxter, 1984; 

Lombarte and Popper, 1994, 2004). 

6. EFFECTS OF ANTHROPOGENIC SOUNDS ON BEHAVIOR 

Perhaps the biggest issue with regard to effects of anthropogenic sound is the potential effects on fish 

behavior. Some potential effects can be suggested based on studies of masking and TTS (Section 4.0). 

However, whether TTS or masking actually impacts behavior or whether other behaviors are affected by 

anthropogenic sound (e.g., leaving a feeding area, changes in migratory paths) is very difficult to study 

and can only be studied using wild animals in the open water. While investigators have, from time to 

time, suggested that behavior can be predicted based on responses to sound in tanks, small cages, or larger 

enclosures, there is always the question as to whether these behaviors are the same as would be 
Fish Hearing and Sensitivity to Acoustic Impacts J-13

encountered in fishes in the wild whose responses were restricted by only their being able to move limited 

distances. As will be discussed below, there are a few studies that give some suggestion as to the 

potential responses of wild fishes to sound sources. 

However, before discussing those results, it is critical to appreciate the complexities associated with 

understanding responses of fishes to increased ambient noise and/or the presence of intense sound 

sources. In fact, fishes may (or may not) show behavioral responses to a sound, and, if a response occurs, 

the nature of the response may vary widely. It is equally important to note that the nature of a response 

(or whether there is a response at all) varies depending on the type of signal heard as well as on the 

motivation of the fishes to respond, the experience of the fishes in the presence of a particular sound or to 

sounds in general, the age of a fish, and many other factors. Thus, predicting behavior is not simply 

correlating sound level or type with a behavior and assuming this behavior will show up every time that 

sound occurs. Instead, a fish may respond to a sound at one time but not at another and the response may 

be predicated on what the fish is otherwise doing when the sound is presented. Therefore, a fish that is 

mating may be less likely to respond to an anthropogenic sound than a fish that is simply swimming 

around, and a fish that has heard the same sound multiple times and does not associate danger with it may 

not respond, whereas a fish that hears the sound for the first time may respond. 

The difficulty of predicting behavior is documented not only in the data on fishes but also from data 

on hearing for amphibians, birds, and mammals (including humans). These data show, in general, that as 

sound levels in the environment increase, animals tend to respond in different ways, which often vary 

depending on the nature of the sound source and sound level as well as on the behavioral state of the 

animal (e.g., what it is doing) when the sound level changes. Responses of animals vary widely 

(reviewed in Brumm and Slabbekoorn [2005]). These may include movement from the area of maximum 

sound level, as shown for several fish species (Engås et al., 1996; Slotte et al., 2004), to changing the 

intensity of calls so they can be heard over the background sounds (Bee and Swanson, 2007) or changing 

the spectrum of the emitted sounds so they are no longer masked, as has been shown in a variety of 

species (Brumm and Slabbekoorn, 2005; Dooling et al., 2009; Parris et al., 2009; Laiolo, 2010; 

Slabbekoorn et al., 2010). 

It is also critical to note that animals (and humans) generally do not respond to sounds when the 

sounds are just detectable (whether there is background sound or not). Sounds generally have to be well 

above the minimal detectable level in order to elicit behavioral responses10. At the lowest sound levels, 

the animal may simply ignore the sound since it is deemed “not important” or from too distant of a 

source. It is only at higher levels where the animal becomes “aware” of the sound and may make a 

decision that it is important or not to behaviorally respond. To put it into terms of masking, it is possible 

that the sound has to be sufficiently above the masked threshold of detection for the animal to be able to 

resolve the signal within the noise and recognize the signal as being of biological relevance. 

By way of example, in an experiment on responses of American shad to sounds produced by their 

predators (dolphins), it was found that if the predator sound is detectable but not very loud the shad will 

not respond (Plachta and Popper, 2003). But, if the sound level is raised by about 8 or 10 dB, the 

American shad will turn and move away from the sound source. Finally, if the sound is made even 

louder, as if a predator were nearby, the American shad go into a frenzied set of motions that probably 

helps them avoid being caught. It was speculated by the researchers that the lowest sound levels were 

recognized by the American shad as being from very distant predators and, thus, not worth a response. At 

somewhat higher levels, the American shad recognized that the predator was closer and started to swim 

away. Finally, the loudest sound was thought to resemble a very nearby predator, eliciting maximum 

response to avoid predation. 

At the same time, there is evidence from a recent study in Norway (Doksaeter et al., 2009) that fishes 

will only respond to sounds that are of biological relevance to them. Doksaeter et al. (2009) showed no 

responses at all from free-swimming herring (Clupea) when exposed to sonars produced by naval vessels. 

Similarly, sounds at the same received level that had been produced by major predators of the herring 

(killer whales) elicited strong flight responses. 

Significantly, the sound levels received by the fishes from the sonar in this experiment were from 

197-209 dB (rms) re 1 μPa at 1-2 kHz. In this frequency range, the hearing threshold for herring that are 

most closely related to those used in the Doksaeter et al. (2009) study is about 125-135 dB re 1 μPa 

 

10 Of course, there are exceptions. A parent will respond to the lowest sound produced by their newborn child, and a person 

walking down a very dark street at night will probably respond to sounds of scraping feet even if they are very quiet. 
J-14 Atlantic G&G Programmatic EIS 

(Mann et al., 2005). This means that the fish showed no reactions to a sound that is biologically 

irrelevant even though the sound was up to 84 dB above the fish’s hearing threshold (209 dB sonar versus 

120 dB threshold). 

It is likely that responses from fishes to any noise source, including pile driving, will show gradations 

in responses similar to the American shad. Therefore, fish responses can be seen as being in several 

sequential steps (see also Figure J-2): 

 Fishes do not hear the sound (it is too low and/or masked). 

 The sound is at a higher level detectable to the fish, but it is sufficiently low that the 

sound is “dismissed” as not being biologically relevant or important. 

 The sound is somewhat higher above threshold, but the fish cannot discriminate it 

from the ambient sounds and so still does not respond (e.g., informational masking). 

 The sound is clearly audible to the fish and recognizable, but the fish does not 

respond or makes only an initial, small response (e.g., startle) and then returns to 

whatever it was doing. In addition, after multiple presentations of the sound, the fish 

may decide that the sound is not biologically important, and the animal habituates 

and no longer shows a startle response. 

 Sound is even louder, and the fish recognizes it as something that may be biologically 

relevant and may change behavior (e.g., swim away or change swimming course). 

But, when the sound ends or after the fish habituates to the sound, the animal returns 

to what it was doing. 

 The fish may totally avoid the very loudest signals if they perceive it as being 

potentially “harmful” and permanently change location or migratory pattern. 

6.1. FISH CATCH AND ANTHROPOGENIC SOUND

Several studies have demonstrated that human-generated sounds may affect the behavior of at least a 

few species of fishes. Engås et al. (1996) examined movement of fishes during and after a seismic airgun 

study by determining catch rate of haddock (Melanogrammus aeglefinus) and Atlantic cod as an indicator 

of fish behavior. These investigators found a significant decline in catch rate of both species that lasted 

for several days after termination of airgun use. Catch rate subsequently returned to normal. The 

conclusion was that the decline in catch rate resulted from the fish moving away from the fishing site as a 

result of the airgun sounds. However, the investigators did not actually observe behavior, and it is 

possible that the fish just changed depth. Another alternative explanation is that the airguns actually 

killed the fish in the area, and the return to normal catch rate occurred because of other fishes entering the 

fishing areas. 

More recent work from the same group (Slotte et al., 2004) showed parallel results for several 

additional pelagic species, including blue whiting and Norwegian spring spawning herring11. However, 

unlike earlier studies from this group, the authors used fishing sonar to observe behavior of the local fish 

schools. They reported that fishes in the area of the airguns appeared to go to greater depths after the 

airgun exposure. Moreover, the abundance of animals approximately 30-50 km (18.6-31.1 mi) away from 

the ensonification increased, suggesting that migrating fish would not enter the zone of seismic activity. 

Similarly, Skalski et al. (1992) showed a 52 percent decrease in rockfish (Sebastes sp.) catch when 

the area of catch was exposed to a single airgun emission at 186-191 dB re 1 Pa (mean peak level) (see 

also Pearson et al. [1987, 1992]). They also demonstrated that fishes would show a startle response to 

sounds as low as 160 dB, but this level of sound did not appear to elicit a decline in catch. 

Culik et al. (2001) conducted a very limited number of experiments to determine catch rate of herring 

(Clupea harengus) in the presence of pingers producing sounds that overlapped with the frequency range 

of herring hearing (2.7-160 kHz). They found no change in catch rate in gill nets with or without the 

higher frequency sounds (>20 kHz) present, although there was an increase in catch rate with the signals 

from 2.7 to 19 kHz (a different source than that of the higher frequency). The results could mean that the 

fish did not “pay attention” to the higher frequency sound or that they did not hear it, or that lower 

 

11 Scientific names for neither species was given in publication. 
Fish Hearing and Sensitivity to Acoustic Impacts J-15

frequency sounds may be attractive to fish. There were no behavioral observations to document how the 

fish actually responded when they detected the sound. 

Most recently, Løkkeborg et al. (2011) repeated the earlier study using a somewhat different 

approach, and the results were different from those found initially. There was some suggestion that the 

fish in this study did not respond to the seismic sounds in these studies, but comparisons are hard to make 

because of substantial experimental differences. However, what these results do suggest is that 

understanding and predicting effects of sound on fishes will not be simple, and that there are many factors 

that come into play in trying to understand fish behavior. 

6.2. OTHER BEHAVIORAL STUDIES

There have been a variety of other behavioral studies, none of which provide conclusive evidence that 

fishes will or will not respond to a particular sound source. For example, Wardle et al. (2001) used a 

video system to examine the behaviors of fishes and invertebrates on a coral reef in response to emissions 

from seismic airguns that were carefully calibrated and measured to have a peak level of 210 dB re 1 μPa 

at 16 m (164 ft) from the source and 195 dB re 1 μPa at 109 m (357.6 ft) from the source. They found no 

substantial or permanent changes in the behavior of the fishes or invertebrates on the reef throughout the 

course of the study, and no animals appeared to leave the reef. There was no indication of any observed 

damage to the animals. 

Mueller-Blenkle et al. (2010) examined responses of several penned Atlantic Ocean species to sounds 

recorded from pile driving, but results were equivocal and could not be used to predict responses of fishes 

to pile driving. Indeed, responses levels were low, and fishes showed some acclimation to the sounds, 

suggesting (though not proving) that fishes might learn to ignore high levels of anthropogenic sound over 

time. 

A study by Jorgenson and Gyselman (2009) may provide some insight into how fishes would behave 

in response to intense anthropogenic sounds12. The authors exposed fishes in the Mackenzie River 

(Northwest Territories, Canada) to seismic airguns and using sonar observed the movements of the fishes. 

The goal was to determine if a seismic survey, using high intensity sounds for long periods of time, could 

impact behavior by changing migratory patterns of fishes. 

The investigators could not determine the species observed by sonar, but based on known river 

inhabitants, they suggest that there were a variety of species present, including those used by Popper et al. 

(2005)13. While results may be limited to one or two species, the investigators found that free-swimming 

fishes observed with sonar showed no response to the airguns with respect to changes in swimming 

direction or speed, even when sound exposure levels (single discharge) were on the order of 

175 dB re 1 μPa2

·s and peak levels of over 200 dB re 1 μPa. 

Finally, Sarà et al. (2007) used divers to observe the behavioral responses of bluefin tuna 

(Thunnus thynnus) in large in-ocean cages (approximately 70 m [229.6 ft] square opening and 30 m 

[98.4 ft] deep) to noise from passing boats. The results showed that the tuna schools would change depth 

and some swimming patterns in the presence of sounds from approaching ferries and hydrofoils (normal 

transport in the region of the cages) and exhibit various other types of behavior in response to sounds 

from small boats. While these results are potentially of interest in suggesting that at least bluefin tuna 

may be disturbed by vessel noise, the authors did not provide sound levels received at the fish. Moreover, 

the fish used are a large oceanic pelagic schooling species (weight of 40-54 kg [88-119 lbs] in this study) 

and the results may not necessarily apply to other species. 

 

12 It should be noted that this study was done on fish in a river, and it is not clear how applicable results would be to fishes in a 

marine environment and, thus, in a much larger expanse of water in which they can move around. 13 The Jorgenson and Gyselman study was conducted just after the Popper et al. (2005) investigation and so it is highly likely that 

the same species, plus additional species, were in the Mackenzie River at the time. 
J-16 Atlantic G&G Programmatic EIS 

7. OTHER ISSUES WITH REGARD TO EFFECTS OF 

ANTHROPOGENIC SOUNDS 

7.1. STRESS

Although an increase in background sound may cause stress in humans14, there have been few studies 

on fishes (e.g., Smith et al., 2004b; Remage-Healey et al., 2006; Wysocki et al., 2006, 2007). There is 

some indication of physiological effects on fishes, such as a change in hormone levels and altered 

behavior, in some (Pickering, 1981; Smith et al., 2004a,b) but not all species tested to date (e.g., Wysocki 

et al., 2007). Sverdrup et al., 1994 found that Atlantic salmon subjected to up to 10 explosions to 

simulate seismic airguns released primary stress hormones, adrenaline and cortisol, as a biochemical 

response. There was no mortality. All experimental subjects returned to their normal physiological levels 

within 72 hrs of exposure. Since stress affects human health, it seems reasonable that stress from loud 

sound may impact fish health, but available information is too limited to adequately address the issue. 

7.2. EGGS AND LARVAE

An additional area of concern is whether high intensity sounds may have an impact on eggs and 

larvae of fishes. Eggs and larvae do not move very much and so must be considered as a stationary object 

with regard to a moving sound source. Thus, the time for impact of sound is relatively small since there 

is no movement relative to the vessel. 

There have been a few studies on effects of sound on eggs and larvae (reviewed extensively in Popper 

and Hastings, 2009b), and there are no definitive conclusions to be reached. At the same time, many of 

the studies have used non-acoustic mechanical signals such as dropping the eggs and larvae or subjecting 

them to explosions (e.g., Lagardère, 1982; Jensen and Alderdice, 1983, 1989; Dwyer et al., 1993). Other 

studies have placed the eggs and/or larvae in very small chambers (e.g., Banner and Hyatt, 1973) where 

the acoustics are not suitable for comparison with what might happen in a free sound field (and even in 

the small chambers, results are highly equivocal). A few studies of the effects of high energy sounds on 

eggs and larvae of invertebrates also provided no definitive evidence of damage, but, like for vertebrates, 

there are insufficient studies to reach firm conclusions as to the effects of sounds on invertebrates 

(Lagardère and Régnault, 1980). 

Several studies did examine effects of sounds on fish eggs and larvae, and, in all cases, there were no 

observed effects on normal survival or hatching, including with the use of sounds that mimic those 

produced by seismic airguns (e.g., Kostyuchenko, 1972). In contrast, Booman et al. (1996) investigated 

the effects of seismic airguns on eggs, larvae, and fry of different larval stages of cod (Gadus morhua), 

saithe (Pollachius virens), herring (Clupea harengus), turbot (Psetta maximus), and plaice (Pleuronectes 

platessa) in field experiments. They exposed fishes to sound source with peak sound pressure levels, 

220-242 dB re 1 μPa2

, and found significant mortality, but only when the specimens were within about 

5 m (16.4 ft) of the source. The most substantial effects were to fishes that were within 1.4 m (4.6 ft) of 

the source. While the authors suggested damage to some cells, such as those of the lateral line, few data 

were reported, and the study is in need of replication. Moreover, it should be noted that the eggs and 

larvae were very close to the airgun array; at such close distances, the particle velocity of the signal would 

be exceedingly large. However, the received sound pressure and particle velocity were not measured in 

this study. 

Jørgensen et al. (2005) examined effects of high intensity pure tones from 1.5 to 6.5 kHz on the 

survival and behavior of larval and juvenile fishes of several species placed in small plastic bags. The 

study used herring (Clupea harengus) (standard lengths 2-5 cm [0.8-1.9 in]), Atlantic cod (Gadus 

morhua) (standard length 2-6 cm [0.8-2.4 in]), saithe (Pollachius virens) (4 cm [1.6 in]), and spotted 

wolffish (Anarhichas minor) (4 cm [1.6 in]) at different developmental stages. Both tissue pathology and 

survival were studied in response to sounds from 150 to 189 dB, and the only effects found were 

20-30 percent mortality in one group of herring larvae at the highest sound levels, but this was not 

replicated. 

 

14 The data here are very complex, and there are many variables in understanding how sound may stress humans or any animal. 

The variables include sound level, duration, frequency spectrum, physiological state of the animal, and innumerable other 

factors. Thus, extrapolation from human stress effects to other organisms is highly problematic and should be done with only 

the most extreme caution. 
Fish Hearing and Sensitivity to Acoustic Impacts J-17

In a follow-up unpublished analysis of these data, Kvadsheim and Sevaldsen (2005) sought to 

understand whether the mid-frequency continuous wave (CW) signals used by Jørgensen et al. (2005) 

would have a significant impact on larvae and juveniles exposed to this sonar in the wild. The 

investigators concluded that the extent of damage/death induced by the sonar would be below the level of 

loss of larval and juvenile fishes from natural causes, and so no concerns should be raised. The only issue 

they did suggest that needs to be considered is when the CW signal is at the resonance frequency of the 

swim bladders of small clupeids. If this is the case, the investigators predict (based on minimal data that 

are in need of replication) that such sounds might increase the mortality of small clupeids that have swim 

bladders that would resonate. 

Most recently, a group in the Netherlands exposed larvae of common sole (Solea solea) to simulated 

pile driving sounds in an apparatus that is very similar to that used by Halvorsen et al. (2011a,b) for larger 

fish (de Jong et al., 2011; L.J. Bolle, pers. comm.15). The larvae of different stages were exposed to 

sound with SELcum of up to 206 dB re 1 μPa2

·s without any affect on fish mortality. In other words, there 

were no differences in mortality between fish exposed to the simulated pile driving sound and fish that 

served as controls. The authors did not, however, look at effects on fish tissue or larval growth, and it is 

possible that either or both of these would have shown an effect of sound exposure. 

 

7.3. INVERTEBRATES

One question that is difficult to answer is the potential effect of high intensity sounds on invertebrates 

(e.g., crabs and cephalopods). There are almost no data on hearing by aquatic invertebrates, and the few 

suggestions of hearing indicates that it is for low frequencies and only to the particle motion component 

of the sound field (e.g., Mooney et al., 2010). There are few data indicating if and how invertebrates may 

use sound in behavior, although a number of species make sounds and so, presumably, use such sounds 

for communication (e.g., Budelmann, 1992; Popper et al., 2001). However, there are no data that indicate 

whether masking occurs in invertebrates or suggest whether sounds from construction would have any 

impact on invertebrate behavior. The one available study on effects of seismic exploration on shrimp 

suggests no behavioral effects at sound levels with a source level of about 196 dB re 1 μPa rms at 1 m 

(3.3 ft) (Andriguetto-Filho et al., 2005). 

There are also no substantive data on whether the high sound levels of any anthropogenic sound 

would have physiological effects on invertebrates. The only potentially relevant data are from a study on 

the effects of seismic exploration on snow crabs on the east coast of Canada (Boudreau et al., 2009). The 

preponderance of evidence from this study showed no short-term or long-term effects of seismic exposure 

in adult or juvenile animals or on eggs. 

Two other studies are important to mention, but only because the results are likely to be referenced. 

It is important to note that both have substantial problems that make them scientifically unsound. An 

unpublished study by Guerra et al. (2004) suggested that there was damage to body tissues in squid that 

had possibly been exposed to high intensity naval sonars. However, there is no evidence that the animals 

were exposed to sonar (only an inference). Moreover, there were no controls for the tissues, and all of the 

animals had died well before they were accessed by the investigators. During this time, it is highly likely 

that the tissue went through normal degenerative processes, therefore, it is impossible to know if the 

damage suggested was from anything other than normal tissue decay. It is also important to note that this 

work, while in the news, was never published in the scientific literature and that the histological analysis 

of the tissue has not been made available for examination by other experts. 

The second study by André et al. (2011) exposed four cephalopod species (Loligo vulgaris, Sepia 

officinalis, Octopus vulgaris, and Illex coindetii) in a tank to sounds and then, after sacrifice of the 

animals, examined the statocysts (which are the ears of cephalopods). The authors show that there is 

some tissue degeneration, and they suggested that the sounds to which the animals were exposed caused 

the damage. However, there are very substantial problems with this study that open the results, and 

conclusions, to serious question. 

First, the only controls provided were never subject to the same handling as the experimental animals. 

The only controls should be animals and tissues exposed to precisely the same conditions and procedures 

15 Personal communication on May 22, 2011 to Dr. Arthur N. Popper. The full report from this study should be released in 

July 2011 and submitted for publication soon thereafter. Dr. Popper reviewed the report at the request of the Dutch regulatory

authority and found it to be an excellent study. 
J-18 Atlantic G&G Programmatic EIS 

as the experimental other than for the variable in question, in this case the sound. However, this was not 

done in this study, and so it is very reasonable to suggest that the overall treatment of the experimental 

animals, including handling, being placed and maintained in the test tank, etc. could have been the cause 

of any effects noted. 

Second, cephalopods, even as indicated by the authors, are detectors of particle motion (just like 

fishes that do not have specializations to couple an air bubble to the ear). The signals to which the 

cephalopods were exposed were measured in pressure (something that the animals do not detect), and 

there was no calibration of the particle motion. Since the exposure was done in a tank with relatively 

flexible walls, it is impossible to predict the particle motion from pressure measurements. Thus, nothing 

in this experiment can relate the sound levels and any damage to the statocysts, even if the damage seen 

was related to the sounds. 

Third, to generalize about invertebrates, it is important to note that the lack of any air bubbles (such 

as the fish swim bladder) that would be set in motion by high intensity sounds leads to the suggestion that 

there would be little or no impact of high intensity sounds on invertebrates (although, like fishes, if the 

invertebrates are very close to the source, the shock wave from the source might have a general impact on 

survival). 

Finally, the authors exposed the animals to sound for 2 hrs, which is far longer than any exposure in 

the wild where the anthropogenic sources of concern, such as sonar and seismic airguns. These are 

generally moving sources, thus they would expose a slower moving (or stationary) animal for just a few 

minutes (if not less) rather than 2 hrs. 

7.4. VESSEL NOISE AND FISH

A growing concern with regard to increases in anthropogenic noise comes from the increasing 

number of commercial ships that are found over large geographic areas as well inshore and the increasing 

number of small pleasure craft found inshore and in harbors. All vessels produce sound as a by-product 

of their operation, which is generally below 1 kHz. Source levels of vessels can range from 

<150 dB re 1 μPa to over 190 dB for the largest commercial vessels (Richardson et al., 1995; Hildebrand, 

2009). 

Vessel noise produces sounds in the general hearing range of fishes (Amoser et al., 2004). 

Continuous exposure (30 minutes) to boat noise has been shown to increase fish cortisol levels (stress 

response) (Wysocki et al., 2006). Temporary threshold shift has been associated with long-term, 

continuous exposure (2 hrs), and masked hearing thresholds have also been recorded for fishes exposed to 

noise from small boats and ferries (Scholik and Yan, 2001; Vasconcelos et al., 2007). Additionally, 

vessels (i.e., trawlers, ferries, small boats) can change fish behavior (e.g., induce avoidance, alter 

swimming speed and direction, and alter schooling behavior) (Sarà et al., 2007). Studies do not indicate 

precisely which of these kinds of physical or behavioral effects may result from a single ship or from an 

aggregation of shipping activity, although it is important to bear in mind that the large number of 

commercial vessels, their nearly continuous presence in many nearshore areas, and projected increases in 

shipping trends. One of the most serious implications of this increase in shipping noise is the impact it 

may have in terms of masking sounds of biological origin and affecting communication between fishes. 

The sounds produced by motor-driven ships causes herring to dive and swim away from the vessel 

(Mitson and Knudsen, 2003). Paradoxically, research vessels specially designed to reduce noise can 

result in an even greater behavioral reaction (Ona et al., 2007). Sand et al. (2008) have pointed out that 

passing ships produce high levels of infrasonic and low-frequency noise (>10-1,000 Hz), and that 

infrasonic frequencies may be responsible for the observed avoidance reactions. 

8. GENERAL CONCLUSIONS – EFFECTS 

The data obtained to date on effects of sound on fishes are very limited both in terms of the number of 

well-controlled studies and in the number of species tested. Moreover, there are significant limits in the 

range of data available for any particular type of sound source. While new data have become available on 

physiological effects of very intense pile driving (Casper et al., 2011a; Halvorsen et al., 2011a,b) and 

these data may be carefully extrapolated to other sound sources and species, the data are still very limited 

and comparable data are needed for other sources and species. 
Fish Hearing and Sensitivity to Acoustic Impacts J-19

At the same time, physiological effects are probably not the major issue with regard to anthropogenic 

sound since most fishes will not be close enough to a sound source to show such effects. Instead, the 

biggest issues are related to effects on behavior since anthropogenic sources could, potentially, impact 

behavior of fishes over broad areas. Yet, despite this clear need for understanding of behavioral effects, 

the extent of data is exceedingly limited and equivocal; it is not yet possible to make clear statements 

about effects of any particular sound source on the behavior of any species. 

The following sections briefly review and comment on the effects discussed earlier in this report. At 

the same time, it should be noted that after examining the complete literature on effects of sound on fishes 

(and turtles), an international panel of experts reached the conclusion that there are insufficient data to 

reach conclusions for most any sound source16. 

The BOEM concludes that there is incomplete or unavailable information (40 CFR 1502.22) about 

the effects of sound on fish, in particular how loud sound may stress fish and influence their health. At 

issue also is our ability to understand what fish experience when we observe or interpret fish response to 

stimuli, such as airguns. While there will never be complete scientific information on the fish species that 

live in OCS waters of the AOI, a body of biological and physiological data and information about the 

effects of sound on fish is available to us. We report where limited data and insufficient knowledge 

challenge our ability to understand these effects. The acquisition of a much more complete knowledge 

base for fish using the AOI cannot be acquired without exhorbitant cost. It certainly cannot be acquired 

in a time frame to make it available for this evaluation. 

The BOEM has therefore determined that data or information on the effects of sound on fish 

identified as incomplete or unavailable is not essential to a reasoned choice among the alternatives, 

including the No Action alternative. We are able to draw basic conclusions despite incomplete or 

unavailable information, discuss results using available scientifically credible information, and apply that 

information using accepted scientific methodologies. 

8.1. PHYSIOLOGICAL EFFECTS

Several general points can be made with reference to effects on fish physiology and mortality of 

intense sounds. 

1. There is little evidence for immediate mortality other than when fishes are very close to 

intense sound sources, such as pile driving for very large piles. There are no data on any 

other sound source. Substantial study needs to be put into questions of immediate 

mortality. 

2. Physiological effects that are sufficient to potentially kill fishes over time appears to have 

some correlation with the total amount of sound exposure. A few non-quantified studies 

have shown no damage to non-auditory tissues as a result of seismic airgun exposure 

(Popper et al., 2005; Song et al., 2008) or to any tissue after exposure to high intensity 

low-frequency and mid-frequency sonars (Halvorsen et al., 2006; Popper et al., 2007). A 

quantified study of pile driving (Halvorsen et al., 2011a,b) demonstrates a range of 

effects that increase in likely impact on the animals, but the fishes seem to recover from 

these effects in a few days (Casper et al., 2011a). There are some data that suggest that 

some seismic airgun signals, under certain acoustic conditions, may damage sensory cells 

of the ears (McCauley et al., 2003), but that there is no effect on other species under 

different acoustic conditions (Song et al., 2008). 

3. There are very few data documenting effects of any intense sound source on eggs and 

larvae. Far more data are needed before any preliminary conclusions can be reached on 

the effects of sound on eggs and larvae, and studies need to include, in addition to 

mortality, effects on growth and body tissues. 

4. It is possible that exposure to loud sounds or increased background noise can result in 

increased stress levels and effects on the immune system. However, such effects have 

never been documented for fishes, and the only long-term study (Wysocki et al., 2007) of 

 

16 This panel was co-chaired by Drs. Arthur Popper and Richard Fay, and a report is in preparation. The work was done under the 

auspices of the Standards Group of the Acoustical Society of America and was funded by several U.S. and international 

agencies and organizations. The report cannot be provided at this point, but will be provided as soon as possible. 
J-20 Atlantic G&G Programmatic EIS 

increased ambient noise showed no effect. It is critical to note that lack of effect may be 

more a function of not enough study rather than being the actual result. Future studies 

are needed to ask questions of such effects. 

8.2. EFFECTS ON FISH BEHAVIOR

The more critical issue for effects of anthropogenic sound on fishes, however, is the effect on the 

behavior of wild animals and whether sound exposure will alter the behavior of a fish in a manner that 

will affect its way of living – such as where it tries to find food or how well it can find a mate. With the 

exception of just a few field studies, there are no data on behavioral effects, and most of these studies are 

very limited in scope and all are related to seismic airguns. Because of the limited ways in which 

behavior of fishes in these studies were “observed” (often by doing catch rates, which tell nothing about 

how fishes really react to a sound), there really are no data on the most critical questions regarding 

behavior. 

Indeed, the fundamental questions are how fishes behave during and after exposure to a sound as 

compared to their “normal” pre-exposure behavior. This requires observations of a great number of 

animals over a large area for a considerable period of time before and after exposure to sound sources as 

well as during exposure. Only with such data is it possible to tell how sounds affect overall behavior 

(including movement) of animals. These experiments are very difficult to do, require a large amount of 

resources, and are very expensive to conduct. 

8.3. INCREASED BACKGROUND SOUND

In addition to questions about how fish movements change in response to sounds, there are also 

questions as to whether any increase in background sound has an effect on more subtle aspects of 

behavior, such as the ability of a fish to hear a potential mate or predator or to glean information about its 

general environment. There is a body of literature that shows that the sound detection ability of fishes can 

be “masked” by the presence of other sounds within the hearing range of the fishes (reviewed in Fay and 

Megela-Simmons, 1999; Popper et al., 2003). Just as a human has trouble hearing another person as the 

room they are in gets noisier, it is likely that the same effect occurs for fishes (as well as all other 

animals). In effect, acoustic communication and orientation of fishes may potentially be restricted by 

noise regimes in their environment that are within the hearing range of the fishes. Perhaps this is the 

single most important area for future study since the masking effects of anthropogenic sounds could have 

a direct impact on the ability of fishes to hear sounds relevant to survival. 

9. CURRENT CRITERIA 

There is considerable national and international concern about effects of anthropogenic sound on 

marine organisms, including fishes (see Popper and Hawkins [2011]). However, despite the concerns, 

there is actually very little in the way of recommendations for regulatory levels of sound. In fact, the only 

known criteria, which are clearly labeled “interim,” arose on the U.S. West Coast out of concern about 

effects of pile driving on fishes (reviewed in Woodbury and Stadler, 2008; Stadler and Woodbury, 2009). 

These criteria are for the onset of physiological effects and say nothing about behavior. 

The current interim criteria are dual in nature. That is, they state that physiological onset may occur 

if the peak sound level of a pile driving strike is 206 dB re 1 μPa or have an SELcum of 187 dB re 1μPa2

-s 

for fishes above 2 g (0.07 oz) or 183 dB re 1μPa2

-s for fishes below 2 g (0.07 oz) (for explanation of these 

criteria, see also Popper et al. [2006] and Carlson et al. [2007]). 

The levels for the current interim criteria were substantially criticized as not being based on the best 

available science at the time of their implementation (see Carlson et al. [2007] for detailed 

recommendations that were not used in setting the current interim criteria). Presently, based on a wide 

range of data that arose concurrent or subsequent to the current interim criteria, it is clear that the set 

levels, at least for cumulative exposure, are far too low and unrealistic for onset of physiological effects. 

The inadequacy of the interim criteria has now been documented in a recent quantified study on the 

effects of pile driving on the onset of physiological effects in Chinook salmon (Halvorsen et al., 2011a,b) 

and several other species (Casper et al., 2011a). These studies, which demonstrated that an SELcum below 

approximately 207 dB re 1μPa2

·s will not result in the onset of injury and that SELcum as high as 
Fish Hearing and Sensitivity to Acoustic Impacts J-21

210 dB re 1μPa2

·s produces physiological effects that are inconsequential (e.g., minor external bleeding). 

While these data need to be replicated for other species and other sounds, they have been shown to be 

appropriate for three very different species, suggesting that there may be reasonably broad applicability of 

these values for setting future interim criteria. 

At the same time, these results are only for pile driving. It is not clear which aspect(s) of intense 

sounds result in physiological onset, but it is likely that the rise time (onset time) of the signal may be of 

consequence. Thus, signals with slower rise times than pile driving may have even higher onset levels 

whereas sounds with faster rise times (e.g., from explosives) may have somewhat lower criteria. 

One other factor that must be recognized with these criteria is recovery time, which is built into the 

West Coast interim criteria (Stadler and Woodbury, 2009). That is, all tissues, when damaged, start to 

recover as soon as the stimulus is removed. This has been documented in mammals exposed to intense 

sounds (reviewed in Popper and Hastings, 2009b), and it is more than likely that the same thing happens 

for fishes. Indeed, Popper et al. (2005) showed recovery of hearing loss resulting from exposure to 

seismic airguns within 18 hrs of the termination of exposure. Thus, if a fish is exposed to pile driving, the 

accumulation of exposure (the SELcum) is returned to zero (0) after 12 hrs without exposure (Carlson et 

al., 2007; Stadler and Woodbury, 2009). 

This same restart of accumulation is important for any sound exposure condition. Thus, no matter 

whether a fish is exposed to pile driving, seismic airguns, sonars, etc., accumulated energy returns to zero 

after some period of non-exposure. 

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APPENDIX K 

 

COOPERATING AGENCY

Cooperating Agency K-3
K-4 Atlantic G&G Programmatic EIS 
Cooperating Agency K-5
K-6 Atlantic G&G Programmatic EIS 
Cooperating Agency K-7
K-8 Atlantic G&G Programmatic EIS 
Cooperating Agency K-9
K-10 Atlantic G&G Programmatic EIS 
Cooperating Agency K-11

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 the 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 communities. 

The Bureau of Ocean Energy Management 

The Bureau of Ocean Energy Management (BOEM) works to manage the 

exploration and development of the nation's offshore resources in a way that 

appropriately balances economic development, energy independence, and 

environmental protection through oil and gas leases, renewable energy 

development and environmental reviews and studies.