Environmental Assessment of a Marine Geophysical Survey by the R/V Melville in the Pacific Ocean off Central and South America, October–November 2010 Prepared for Scripps Institution of Oceanography 8602 La Jolla Shores Drive La Jolla, CA. 92037 and National Science Foundation Division of Ocean Sciences 4201 Wilson Blvd., Suite 725 Arlington, VA 22230 by LGL Ltd., environmental research associates 22 Fisher St., POB 280 King City, Ont. L7B 1A6 25 May 2010 Revised 13 July and 16 September 2010 LGL Report TA4902-1 Table of Contents TABLE OF CONTENTS Page ABSTRACT.................................................................................................................................................. vi LIST OF ACRONYMS .................................................................................................................................. vii I. PURPOSE AND NEED ................................................................................................................................ 1 II. ALTERNATIVES INCLUDING PROPOSED ACTION .................................................................................... 2 Proposed Action ............................................................................................................................... 2 (1) Project Objectives and Context ......................................................................................... 2 (2) Proposed Activities ........................................................................................................... 2 (3) Monitoring and Mitigation Measures................................................................................ 7 Alternative Action: Another Time .................................................................................................. 12 No Action Alternative .................................................................................................................... 12 III. AFFECTED ENVIRONMENT .................................................................................................................. 12 Protected Areas............................................................................................................................... 12 (1) Cocos Island National Park, Costa Rica ......................................................................... 12 (2) Coiba National Park and its Special Zone of Marine Protection, Republic of Panama....................................................................................................................... 13 (3) Malpelo Fauna and Flora Sanctuary, Colombia .............................................................. 13 (4) Galápagos Biological Marine Resources Reserve ........................................................... 14 Marine Mammals ........................................................................................................................... 14 (1) Mysticetes ....................................................................................................................... 17 (2) Odontocetes .................................................................................................................... 22 (3) Pinnipeds ........................................................................................................................ 36 Sea Turtles ...................................................................................................................................... 37 (1) Leatherback Turtle .......................................................................................................... 38 (2) Loggerhead Turtle .......................................................................................................... 39 (3) Green Turtle.................................................................................................................... 40 (4) Hawksbill Turtle ............................................................................................................. 41 (5) Olive Ridley Turtle ......................................................................................................... 42 IV. ENVIRONMENTAL CONSEQUENCES .................................................................................................... 44 Proposed Action ............................................................................................................................. 44 (1) Direct Effects on Marine Mammals and Sea Turtles and Their Significance .................. 44 (2) Mitigation Measures ....................................................................................................... 58 (3) Numbers of Marine Mammals that could be Exposed to Various Received Sound Levels ........................................................................................................................ 58 (4) Conclusions for Marine Mammals and Sea Turtles ........................................................ 63 (5) Direct Effects on Fish and Their Significance ................................................................ 64 (6) Direct Effects on Invertebrates and Their Significance ................................................... 66 (7) Indirect Effects on Marine Mammals, Sea Turtles, and Their Significance .................... 68 (8) Cumulative Effects ......................................................................................................... 68 (9) Unavoidable Impacts ...................................................................................................... 76 (10) Coordination with Other Agencies and Processes ......................................................... 76 Environmental Assessment for SIO ETP Cruise, 2010 Page iii Table of Contents Alternative Action: Another Time .................................................................................................. 77 No Action Alternative .................................................................................................................... 77 V. LIST OF PREPARERS ............................................................................................................................. 78 VI. LITERATURE CITED ............................................................................................................................ 79 Marine Mammals and Acoustics .................................................................................................... 79 Sea Turtles, Fish, and Other ........................................................................................................... 99 APPENDIX A: REVIEW OF THE EFFECTS OF AIRGUN SOUNDS ON MARINE MAMMALS......................... 109 1. Categories of Noise Effects ..................................................................................................... 109 2. Hearing Abilities of Marine Mammals .................................................................................... 109 2.1 Toothed Whales............................................................................................................ 110 2.2 Baleen Whales .............................................................................................................. 111 2.3 Seals and Sea Lions ...................................................................................................... 111 2.4 Manatees and Dugong .................................................................................................. 112 2.5 Sea Otter and Polar Bear .............................................................................................. 112 3. Characteristics of Airgun Sounds ............................................................................................ 112 4. Masking Effects of Airgun Sounds .......................................................................................... 114 5. Disturbance by Seismic Surveys .............................................................................................. 116 5.1 Baleen Whales .............................................................................................................. 117 5.2 Toothed Whales............................................................................................................ 123 5.3 Pinnipeds ...................................................................................................................... 129 5.4 Sirenians, Sea Otter and Polar Bear .............................................................................. 131 6. Hearing Impairment and Other Physical Effects of Seismic Surveys ...................................... 131 6.1 Temporary Threshold Shift .......................................................................................... 132 6.2 Permanent Threshold Shift ........................................................................................... 137 6.3 Strandings and Mortality .............................................................................................. 139 6.4 Non-Auditory Physiological Effects ............................................................................. 141 7. Literature Cited ........................................................................................................................ 141 APPENDIX B: REVIEW OF THE EFFECTS OF AIRGUN SOUNDS ON SEA TURTLES ................................... 157 1. Sea Turtle Hearing ................................................................................................................... 157 2. Effects of Airgun Pulses