| | Environmental Assessment of a Planned Low-Energy Marine |
| | 1,07 | | MB | Seismic Survey by the Scripps Institution of Oceanography on |
| | 133 | | stron | the Louisville Ridge in the Southwest Pacific Ocean, |
| | January–February 2006 |
| | 4960 | | ID | LGL Limited |
| | 2005 | | rok |
| | TABLE OF CONTENTS |
| | ABSTRACTV |
| | LIST OF ACRONYMS .VII |
| | I. PURPOSE AND NEED 1 |
| | II. ALTERNATIVES INCLUDING PROPOSED ACTION. 2 |
| | Proposed Action2 |
| | (1) Project Objectives and Context.2 |
| | (2) Proposed Activities .2 |
| | (3) Mitigation Measures6 |
| | Alternative Action: Another Time 11 |
| | No Action Alternative.11 |
| | III. AFFECTED ENVIRONMENT.12 |
| | Physical Environment 12 |
| | Marine Mammals .12 |
| | Pinnipeds 15 |
| | Odontocetes 15 |
| | Mysticetes 30 |
| | Sea Turtles36 |
| | Leatherback Turtle 36 |
| | Loggerhead Turtle . 37 |
| | Green Turtle 38 |
| | Hawksbill Turtle . 38 |
| | Olive Ridley Turtle 39 |
| | IV. ENVIRONMENTAL CONSEQUENCES 40 |
| | Proposed Action40 |
| | (1) Direct Effects and their Significance. 40 |
| | (2) Mitigation Measures 52 |
| | (3) Numbers of Marine Mammals that May be “Taken by Harassment” . 52 |
| | (4) Indirect Effects and Their Significance . 61 |
| | (5) Cumulative Effects 67 |
| | (6) Unavoidable Impacts. 69 |
| | Alternative Action: Another Time 69 |
| | No Action Alternative.69 |
| | V. LIST OF PREPARERS70 |
| | VI. LITERATURE CITED.71 |
| | Marine Mammals and Acoustics.71 |
| | Table of Contents |
| | SIO Environmental Assessment for Louisville Ridge Page iv |
| | Sea Turtles, Fish, and Other85 |
| | APPENDIX A: Review of Potential Impacts of airgun sounds on marine mammals 91 |
| | (a) Categories of Noise Effects.91 |
| | (b) Hearing Abilities of Marine Mammals .92 |
| | Toothed Whales 92 |
| | Baleen Whales 92 |
| | Pinnipeds 93 |
| | Sirenians . 93 |
| | (c) Characteristics of Airgun Pulses .93 |
| | (d) Masking Effects of Seismic Surveys95 |
| | (e) Disturbance by Seismic Surveys 96 |
| | Baleen Whales 97 |
| | Toothed Whales 100 |
| | Pinnipeds 102 |
| | (f) Hearing Impairment and Other Physical Effects.104 |
| | Temporary Threshold Shift 105 |
| | Permanent Threshold Shift . 107 |
| | (g) Strandings and Mortality .109 |
| | (h) Non-auditory Physiological Effects .110 |
| | Literature Cited111 |
| | APPENDIX B: Review of Potential Impacts of airgun sounds on Sea Turtles 119 |
| | Sea Turtle Hearing .119 |
| | Effects of Airgun Pulses on Behavior and Movements .121 |
| | Possible Impacts of Airgun Sounds .123 |
| | Hearing Loss. 123 |
| | Behavioral and Distributional Effects . 124 |
| | Conclusions .125 |
| | Literature Cited125 |