QUANTIFYING TEMPORAL AND SPATIAL ECOSYSTEM VARIABILITY ACROSS THE NORTHERN GULF OF ALASKA TO UNDERSTAND MECHANISMS OF CHANGE SCIENCE SYNTHESIS REPORT FOR THE GULF WATCH ALASKA PROGRAM PROGRAM NUMBERS: 14120114 AND 14120120 EXXON VALDEZ OIL SPILL TRUSTEE COUNCIL SEPTEMBER 1, 2015 Tammy Hoem Neher, Brenda Ballachey, Katrina Hoffman, Kris Holderied, Russell Hopcroft, Mandy Lindeberg, Molly McCammon, and Tom Weingartner, editors and contributing authors With articles by Gulf Watch Alaska scientists and staff members: Sonia Batten, Robert Campbell, Craig Matkin, John Moran, Janice Straley, Mayumi Arimitsu, John Piatt, Kathy Kuletz, Daniel Esler, Heather Coletti, Tammy Wilson, Daniel Cushing, Mary Anne Bishop, Jessica Couture, James Bodkin, Tom Dean, George Esslinger, Katrin Iken, Brenda Konar, Kim Kloecker, Daniel Monson, Michael Shephard, Ben Weitzman, Mark Carls, Tuula Hollmen, and Suresh Sethi. i TABLE OF CONTENTS Table of Contents ................................................................................................................................................................. ii Executive Summary ............................................................................................................................................................. v Summary of Key Findings .......................................................................................................................................... vi Use of Gulf Watch Alaska Data For Resource Management ........................................................................ viii Overall Program Recommendations .......................................................................................................................... x Chapter 1 Program Introduction and Background .......................................................................................................... 1 Chapter Overview ................................................................................................................................................................ 1 Historical context ................................................................................................................................................................. 1 Current Hypotheses for Gulf of Alaska Ecosystem Dynamics .............................................................................. 3 The EVOS-affected Region .............................................................................................................................................. 5 Gulf Watch Alaska: Consortium-based Monitoring ................................................................................................. 6 Addressing Management Needs and Research Questions ............................................................................... 10 Moving Forward: Future Vision for the Gulf Watch Alaska program ........................................................ 14 References ............................................................................................................................................................................ 15 Chapter 2 Environmental Drivers: Regional Variability in Oceanographic Patterns Across the Gulf of Alaska. ................................................................................................................................................................................... 2—1 Research Summary: Long-term Monitoring of Oceanographic Conditions in the Alaska Coastal Current from Hydrographic Station GAK 1 ...................................................................................................... 2—12 The Seward Line: 17 years of pattern and variability in the coastal Gulf of Alaska. ........................... 2—20 Linking Variability in Oceanographic Patterns Between Nearshore and Shelf Waters Across the Gulf of Alaska ....................................................................................................................................................................... 2—25 Research Summary: Interannual variability in lower trophic levels on the Alaskan Shelf ................ 2—37 Research Summary: Hydrographic trends in Prince William Sound, Alaska, 1960-2013. ................ 2—42 Chapter 3 Variability within Pelagic Ecosystems of Prince William Sound ................................................... 3—1 Research Summary: Long-term killer whale monitoring in Prince William Sound/ Kenai Fjords . 3—11 Research Summary: Long-term Monitoring of Humpback Whale Predation on Pacific Herring .... 3—21 ii Forage Fish Populations in Prince William Sound: Designing Efficient Monitoring Techniques to Detect Change ............................................................................................................................................................. 3—34 Spatial and Temporal Variation in Marine Birds in the Northern Gulf of Alaska: The Value of Marine Bird Monitoring within Gulf Watch Alaska ...................................................................................................... 3—47 Nearshore Marine Bird Surveys: data synthesis, analysis and recommendations for sampling frequency and intensity to detect population trends ............................................................................................................ 3—53 Research Summary: Temporal change in a subarctic marine bird community linked to habitat and climate change ............................................................................................................................................................. 3—61 Research Summary: Long-term monitoring of seabird abundance and habitat associations during late fall and winter in Prince William Sound ............................................................................................................ 3—70 Chapter 3-Appendix 1: Summary of marine birds projects in the Gulf Watch Alaska region . 3—79 Chapter 4 Variability within Nearshore Ecosystems of the Gulf of Alaska .................................................... 4—1 Research Summary: Project Summary: Influence of static habitat attributes on local and regional biological variability in rocky intertidal communities of the northern Gulf of Alaska ........................... 4—8 Pacific blue mussel (Mytilus trossulus) Abundance in the Gulf of Alaska: synthesis of gulf watch data (2006-2013) and a Consideration of Major Recruitment events (1989-2013) ........................................ 4—16 Chapter 5 Lingering Oil Monitoring ............................................................................................................................ 5—1 Timelines and Mechanisms of Wildlife Population Recovery Following the Exxon Valdez Oil Spill . 5— 6 Chapter 6 Conceptual Models ........................................................................................................................................ 6—1 Conceptual Model Development .............................................................................................................................. 6—1 General Ecosystem Model.......................................................................................................................................... 6—1 Sub-Models ..................................................................................................................................................................... 6—2 Management-linked sub-models and decision support tools ........................................................................... 6—6 Chapter 7 Program Summary and Recommendations ............................................................................................ 7—1 Monitoring Highlights and Ecological Significance .......................................................................................... 7—1 Environmental Drivers ........................................................................................................................................... 7—1 Pelagic Ecosystems ................................................................................................................................................. 7—2 Nearshore Ecosystems ............................................................................................................................................ 7—2 iii Recommendations for future work .......................................................................................................................... 7—3 Overall Program Recommendations .................................................................................................................. 7—3 Environmental Drivers Component ................................................................................................................... 7—5 Pelagic Ecosystems Component.......................................................................................................................... 7—5 Nearshore Ecosystems Component .................................................................................................................... 7—6 Lingering Oil Component ..................................................................................................................................... 7—6 ACKNOWLEDGEMENTS This document is a summary of works contributed by numerous scientists with funding leveraged from both non-governmental and governmental entities to provide staff time and equipment. We wish to thank all of