Environmental Assessment of a Low-Energy Marine Geophysical Survey by the R/V Marcus G
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Environmental Assessment of a Low-Energy Marine Geophysical Survey by the R/V Marcus G. Langseth in the Central Pacific Ocean, May 2012 Prepared for Lamont-Doherty Earth Observatory 61 Route 9W, P.O. Box 1000 Palisades, NY 10964-8000 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 30 November 2011 Revised 12 December 2011 LGL Report TA8098-1 Environmental Assessment for L-DEO’s Line Islands Seismic Survey, 2012 Page ii Table of Contents TABLE OF CONTENTS Page ABSTRACT .................................................................................................................................................... vi LIST OF ACRONYMS ................................................................................................................................... viii 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 ................................................................................. 6 Alternative Action: Another Time .................................................................................................... 11 No Action Alternative ...................................................................................................................... 11 III. AFFECTED ENVIRONMENT .................................................................................................................... 12 Oceanography ................................................................................................................................... 12 Protected Areas ................................................................................................................................. 12 Marine Mammals .............................................................................................................................. 13 (1) Mysticetes ......................................................................................................................... 13 (2) Odontocetes ...................................................................................................................... 19 (3) Pinniped ............................................................................................................................ 28 Sea Turtles ........................................................................................................................................ 28 (1) Green Turtle ..................................................................................................................... 29 (2) Hawksbill Turtle ............................................................................................................... 29 (3) Leatherback Turtle ........................................................................................................... 30 (4) Olive Ridley Turtle ........................................................................................................... 31 (5) Loggerhead Turtle ............................................................................................................ 33 Seabirds ............................................................................................................................................ 34 (1) Newell’s Shearwater ......................................................................................................... 34 (2) Hawaiian Petrel ................................................................................................................ 35 (3) Band-rumped storm petrel ................................................................................................ 35 (4) Black-footed Albatross ..................................................................................................... 35 IV. ENVIRONMENTAL CONSEQUENCES...................................................................................................... 35 Proposed Action ............................................................................................................................... 35 (1) Direct Effects and Their Significance on Marine Mammals and Sea Turtles .................. 35 (2) Mitigation Measures for Marine Mammals and Sea Turtles ............................................ 52 (3) Numbers of Marine Mammals that Could be “Taken by Harassment” ............................ 52 (4) Conclusions for Marine Mammals and Sea Turtles ......................................................... 57 (5) Direct Effects on Fish and Their Significance .................................................................. 58 (6) Direct Effects on Invertebrates and Their Significance .................................................... 60 (7) Direct Effects on Seabirds and Their Significance ........................................................... 62 (8) Indirect Effects on Marine Mammals, Sea Turtles, Seabirds, and Their Significance ................................................................................................................. 63 Environmental Assessment for L-DEO’s Line Islands Seismic Survey, 2012 Page iii Table of Contents (9) Cumulative Effects ........................................................................................................... 64 (10) Unavoidable Impacts ...................................................................................................... 67 (11) Coordination with Other Agencies and Processes .......................................................... 67 Alternative Action: Another Time .................................................................................................... 68 No Action Alternative ...................................................................................................................... 68 V. LIST OF PREPARERS ................................................................................................................................ 69 VI. LITERATURE CITED ............................................................................................................................... 70 Marine Mammals and Acoustics ...................................................................................................... 70 Sea Turtles, Seabirds, Fish, and Other .............................................................................................. 91 APPENDIX A: REVIEW OF THE EFFECTS OF AIRGUN SOUNDS ON MARINE MAMMALS ......................... 103 1. Categories of Noise Effects ....................................................................................................... 103 2. Hearing Abilities of Marine Mammals ...................................................................................... 103 2.1 Toothed Whales (Odontocetes) ...................................................................................... 104 2.2 Baleen Whales (Mysticetes) ........................................................................................... 104 2.3 Seals and Sea Lions (Pinnipeds) .................................................................................... 105 2.4 Manatees and Dugong (Sirenians) ................................................................................. 105 2.5 Sea Otter and Polar Bear ................................................................................................ 106 3. Characteristics of Airgun Sounds .............................................................................................. 106 4. Masking Effects of Airgun Sounds ........................................................................................... 108 5. Disturbance by Seismic Surveys ............................................................................................... 110 5.1 Baleen Whales ................................................................................................................ 111 5.2 Toothed Whales ............................................................................................................. 117 5.3 Pinnipeds ........................................................................................................................ 123 5.4 Sirenians, Sea Otter and Polar Bear ............................................................................... 125 6. Hearing Impairment and Other Physical Effects of Seismic Surveys ....................................... 125 6.1 Temporary Threshold Shift (TTS) ................................................................................. 126 6.2 Permanent Threshold Shift (PTS) .................................................................................. 131 6.3 Strandings and Mortality ................................................................................................ 133 6.4 Non-Auditory Physiological Effects .............................................................................