3.4 Marine Mammals Mariana Islands Training and Testing Final Supplemental EIS/OEIS June 2020 Supplemental Environmental Impact Statement/ Overseas Environmental Impact Statement Mariana Islands Training and Testing TABLE OF CONTENTS 3.4 Marine Mammals ............................................................................................................. 3.4-1 3.4.1 Affected Environment........................................................................................... 3.4-1 3.4.1.1 General Background ................................................................................ 3.4-1 3.4.1.2 Species Unlikely to Be Present in the Study Area .................................... 3.4-3 3.4.1.3 Group Size ................................................................................................ 3.4-3 3.4.1.4 Habitat Use .............................................................................................. 3.4-4 3.4.1.5 Dive Behavior ........................................................................................... 3.4-4 3.4.1.6 Hearing and Vocalization ......................................................................... 3.4-4 3.4.1.7 General Threats ....................................................................................... 3.4-8 3.4.1.8 Blue Whale (Balaenoptera musculus) .................................................... 3.4-16 3.4.1.9 Bryde’s Whale (Balaenoptera edeni) ..................................................... 3.4-17 3.4.1.10 Fin Whale (Balaenoptera physalus) ..................................................... 3.4-18 3.4.1.11 Humpback Whale (Megaptera novaeangliae) .................................... 3.4-19 3.4.1.12 Minke Whale (Balaenoptera acutorostrata) ....................................... 3.4-23 3.4.1.13 Omura’s Whale (Balaenoptera omurai) .............................................. 3.4-24 3.4.1.14 Sei Whale (Balaenoptera borealis) ...................................................... 3.4-25 3.4.1.15 Blainville’s Beaked Whale (Mesoplodon densirostris) ......................... 3.4-25 3.4.1.16 Common Bottlenose Dolphin (Tursiops truncatus) ............................. 3.4-27 3.4.1.17 Cuvier’s Beaked Whale (Ziphius cavirostris) ........................................ 3.4-28 3.4.1.18 Dwarf Sperm Whale (Kogia sima) ........................................................ 3.4-30 3.4.1.19 False Killer Whale (Pseudorca crassidens) ........................................... 3.4-30 3.4.1.20 Fraser’s Dolphin (Lagenodelphis hosei) ............................................... 3.4-32 3.4.1.21 Ginkgo-Toothed Beaked Whale (Mesoplodon ginkgodens) ................ 3.4-32 3.4.1.22 Killer Whale (Orcinus orca) .................................................................. 3.4-34 3.4.1.23 Longman’s Beaked Whale (Indopacetus pacificus) ............................. 3.4-35 3.4.1.24 Melon-Headed Whale (Peponocephala electra) ................................. 3.4-36 i Table of Contents Mariana Islands Training and Testing Final Supplemental EIS/OEIS June 2020 3.4.1.25 Pantropical Spotted Dolphin (Stenella attenuata) .............................. 3.4-37 3.4.1.26 Pygmy Killer Whale (Feresa attenuata) ............................................... 3.4-38 3.4.1.27 Pygmy Sperm Whale (Kogia breviceps) ............................................... 3.4-39 3.4.1.28 Risso’s Dolphin (Grampus griseus) ...................................................... 3.4-40 3.4.1.29 Rough-Toothed Dolphin (Steno bredanensis) ...................................... 3.4-41 3.4.1.30 Short-Finned Pilot Whale (Globicephala macrorhynchus) .................. 3.4-42 3.4.1.31 Sperm Whale (Physeter macrocephalus) ............................................. 3.4-43 3.4.1.32 Spinner Dolphin (Stenella longirostris) ................................................ 3.4-45 3.4.1.33 Striped Dolphin (Stenella coeruleoalba) .............................................. 3.4-47 3.4.2 Environmental Consequences ............................................................................ 3.4-48 3.4.2.1 Acoustic Stressors .................................................................................. 3.4-51 3.4.2.2 Explosive Stressors ............................................................................... 3.4-196 3.4.2.3 Energy Stressors................................................................................... 3.4-263 3.4.2.4 Physical Disturbance and Strike Stressors ........................................... 3.4-265 3.4.2.5 Entanglement Stressors ....................................................................... 3.4-267 3.4.2.6 Ingestion Stressors ............................................................................... 3.4-268 3.4.2.7 Secondary Stressors ............................................................................. 3.4-270 3.4.3 Summary of Potential Impacts on Marine Mammals ....................................... 3.4-271 3.4.3.1 Combined Impacts of All Stressors Under Alternative 1 ..................... 3.4-273 3.4.3.2 Combined Impacts of All Stressors Under Alternative 2 (Preferred Alternative) .......................................................................................... 3.4-273 3.4.3.3 Combined Impacts of All Stressors Under the No Action Alternative . 3.4-273 3.4.3.4 Summary of Monitoring and Observations During Navy Activities Since 2015 ..................................................................................................... 3.4-274 3.4.4 Marine Mammal Protection Act Determinations ............................................. 3.4-277 3.4.5 Endangered Species Act Determinations ......................................................... 3.4-277 3.4.6 Public Comments .............................................................................................. 3.4-278 List of Figures Figure 3.4-1: Composite Audiograms for Hearing Groups Likely Found in the Study Area .................... 3.4-7 Figure 3.4-2: Two Hypothetical Threshold Shifts .................................................................................. 3.4-57 Figure 3.4-3: Odontocete Critical Ratios ............................................................................................... 3.4-65 Figure 3.4-4: Critical Ratios for Different Noise Types .......................................................................... 3.4-66 Figure 3.4-5: Navy Auditory Weighting Functions for all Species Groups .......................................... 3.4-107 ii Table of Contents Mariana Islands Training and Testing Final Supplemental EIS/OEIS June 2020 Figure 3.4-6: TTS and PTS Exposure Functions for Sonar and Other Transducers .............................. 3.4-108 Figure 3.4-7: Behavioral Response Function for Odontocetes ........................................................... 3.4-110 Figure 3.4-8: Behavioral Response Function for Mysticetes .............................................................. 3.4-111 Figure 3.4-9: Behavioral Response Function for Beaked Whales ....................................................... 3.4-111 Figure 3.4-10: Relative Likelihood of a Response Being Significant Based on the Duration and Severity of Behavioral Reactions ...................................................................................................... 3.4-113 Figure 3.4-11: Blue Whale Impacts Estimated per Year from Sonar and Other Transducers Used During Training and Testing Under Alternative 1 ...................................................................... 3.4-130 Figure 3.4-12: Blue Whale Impacts Estimated per Year from Sonar and Other Transducers Used During Training and Testing Under Alternative 2 ...................................................................... 3.4-131 Figure 3.4-13: Bryde’s Whale Impacts Estimated per Year from Sonar and Other Transducers Used During Training and Testing Under Alternative 1 .......................................................... 3.4-132 Figure 3.4-14: Bryde’s Whale Impacts Estimated per Year from Sonar and Other Transducers Used During Training and Testing Under Alternative 2 .......................................................... 3.4-133 Figure 3.4-15: Fin Whale Impacts Estimated per Year from Sonar and Other Transducers Used During Training and Testing Under Alternative 1 ...................................................................... 3.4-135 Figure 3.4-16: Fin Whale Impacts Estimated per Year from Sonar and Other Transducers Used During Training and Testing Under Alternative 2 ...................................................................... 3.4-136 Figure 3.4-17: Humpback Whale Impacts Estimated per Year from Sonar and Other Transducers Used During Training and Testing Under Alternative 1 .......................................................... 3.4-137 Figure 3.4-18: Humpback Whale Impacts Estimated per Year from Sonar and Other Transducers Used During Training and Testing Under Alternative 2 .......................................................... 3.4-139 Figure 3.4-19: Minke Whale Impacts Estimated per Year from Sonar and Other Transducers Used During Training and Testing Under Alternative 1 ...................................................................... 3.4-140 Figure 3.4-20: Minke Whale Impacts Estimated per Year from Sonar and Other Transducers Used During Training and Testing Under Alternative 2 ...................................................................... 3.4-141 Figure 3.4-21: Omura’s Whale Impacts Estimated per Year from Sonar and Other Transducers