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FINAL SPECIES STATUS ASSESSMENT for the PACIFIC WALRUS (Odobenus Rosmarus Divergens), May 2017 (Version 1.0)

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FINAL SPECIES STATUS ASSESSMENT for the PACIFIC WALRUS (Odobenus Rosmarus Divergens), May 2017 (Version 1.0) FINAL SPECIES STATUS ASSESSMENT FOR THE PACIFIC WALRUS (Odobenus rosmarus divergens), May 2017 (Version 1.0) James G. MacCracken, William S. Beatty, Joel L. Garlich-Miller, Michelle L. Kissling, Jonathan A. Snyder U.S. Fish and Wildlife Service, Marine Mammals Management, 1011 E. Tudor Rd.MS-341, Anchorage, AK 99503 LIST OF ACRONYMS ADEC – Alaska Department of Environmental Conservation ADFG – Alaska Department of Fish and Game AK – Alaska BBN – Bayesian Belief Network BOEM – Bureau of Ocean Energy Management CACO3 – calcium carbonates CCR – calf:cow ratio CMIP – Coupled Model Intercomparison Project CO2 – carbon dioxide CPT – Conditional Probability Table ESA – Endangered Species Act EWC – Eskimo Walrus Commission GCM – Global (or General) Circulation Model GHG – Greenhouse Gas IPCC - Intergovernmental Panel on Climate Change ITR – Incidental Take Regulation LOA – Letter of Authorization LTK – local and traditional ecological knowledge MMPA – Marine Mammal Protection Act NSR – Northern Sea Route NWP – Northwest Passage OA – ocean acidification RCP – Representative Concentration Pathway SSA – Species Status Assessment SST – Sea Surface Temperature TEK – traditional ecological knowledge USFWS – US Fish and Wildlife Service USGS – US Geological Survey USSR – Union of Soviet Socialist Republics YBP – years before present ii iii CONTENTS List of Acronyms ............................................................................................................................................ ii Executive Summary ....................................................................................................................................... 8 1. Introduction .............................................................................................................................................. 9 1.1 Review of Previous Listing Actions ...................................................................................................... 9 1.2 Purpose of this Assessment .............................................................................................................. 10 2. Description of the Pacific Walrus ............................................................................................................ 11 2.1 Taxonomy .......................................................................................................................................... 12 2.2 Subspecies Description and Needs ................................................................................................... 14 2.2.1 Behavior ..................................................................................................................................... 14 2.2.2 Feeding and Prey ........................................................................................................................ 14 2.2.3 Seasonal Distributions................................................................................................................ 16 2.2.4 Habitat Use................................................................................................................................. 19 2.3 Vital Rates ......................................................................................................................................... 24 2.3.1 Reproduction and Productivity .................................................................................................. 24 2.4 Population Abundance and Trends ................................................................................................... 25 2.4.1 Population Modelling ................................................................................................................. 26 2.4.2 Population Indices ...................................................................................................................... 26 2.5 Adaptive Capacity of Pacific Walruses .............................................................................................. 29 2.5.1 Evolutionary History of the Pacific Walrus ................................................................................ 29 2.5.2 Behavioral Adaptation of Pacific Walruses ................................................................................ 30 2.5.3 Intrinsic Adaptive Capacity of Pacific Walruses ......................................................................... 31 3. Current Resource Conditions .................................................................................................................. 33 3.1 Marine Habitats ................................................................................................................................ 33 3.1.1. Sea Ice ....................................................................................................................................... 33 3.1.2 Annual Trends in Sea Ice ............................................................................................................ 35 3.1.3 Effects of Sea Ice Changes on Pacific Walruses ......................................................................... 36 3.1.4 Ocean Warming ......................................................................................................................... 36 3.1.5 Ocean and Benthic Productivity ................................................................................................. 37 3.1.6 Ocean Acidification .................................................................................................................... 40 3.2 Coastal Habitats ................................................................................................................................ 43 4 3.2.1 Use of Bristol Bay Haulouts ........................................................................................................ 43 3.2.2 Use of Chukchi Sea Haulouts ..................................................................................................... 43 3.2.3 Haulout Mortalities .................................................................................................................... 44 3.3 Harvest .............................................................................................................................................. 46 3.3.1 History of Harvest ...................................................................................................................... 47 3.3.2 Harvest Patterns ........................................................................................................................ 47 3.3.3 Harvest Sustainability................................................................................................................. 49 3.4 Disease and Parasites ........................................................................................................................ 50 3.4.1 Infectious Disease ...................................................................................................................... 50 3.4.2 Parasites ..................................................................................................................................... 51 3.5 Predation ........................................................................................................................................... 52 3.5.1 Polar Bears ................................................................................................................................. 52 3.5.2 Killer Whales .............................................................................................................................. 53 3.6 Contaminants and Biotoxins ............................................................................................................. 53 3.6.1. Persistent Organic Pollutants .................................................................................................... 54 3.6.2 Heavy Metals.............................................................................................................................. 54 3.6.3 Radionuclides ............................................................................................................................. 55 3.6.4 Biotoxins ..................................................................................................................................... 56 3.7 Oil and Gas Exploration, Development, and Production .................................................................. 56 3.8 Commercial Fisheries ........................................................................................................................ 60 3.9 Ship and Air Traffic ............................................................................................................................ 63 3.9.1 Shipping ...................................................................................................................................... 63 3.9.2 Air Traffic .................................................................................................................................... 68 3.10 Existing Regulatory Protections ...................................................................................................... 68 3.11 Local and Traditional Ecological Knowledge ................................................................................... 69 3.12 Resiliency, Representation, and Redundancy of the Pacific walrus ............................................... 72 3.12.1 Resiliency ................................................................................................................................
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