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i The Bering Sea Ecosystem Committee on the Bering Sea Ecosystem Polar Research Board Commission on Geosciences, Environment, and Resources National Research Council NATIONAL ACADEMY PRESS Washington, D.C. 1996
ii NOTICE: The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Bruce M. Alberts is president of the National Academy of Sciences. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineer- ing programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Harold Leibowitz is president of the National Academy of Engineering. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initia- tive, to identify issues of medical care, research, and education. Dr. Kenneth I. Shine is president of the Institute of Medicine. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of sci- ence and technology with the Academy's purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Bruce M. Alberts and Dr. Harold Leibowitz are chairman and vice chairman, respectively, of the National Research Council. The project that is the subject of this report was approved by the Governing Board of the National Research Council, whose members are drawn from the councils of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. The members of the committee responsible for the report were chosen for their special competences and with regard for appropriate balance. This report has been reviewed by a group other than the authors according to procedures approved by a Report Review Committee con- sisting of members of the National Academy of Sciences, the National Academy of Engineering, and the Institute of Medicine. Support for this project was provided by the U.S. Department of State under Grant No. 1758-200303 and the United States Coast Guard under Grant No. DTCG23-93-P-HNF037. Cover: This image was produced by WorldSat International and Jim Knighton for the Alaska Department of Commerce and Economic Development. The image is derived from a cloud free mosaic of satellite images taken from the NOAA weather satellites that orbit the Earth at an altitude of approximately 800km (520 miles). The image is based on one infrared channel and one visible channel of NOAA data from which RGB bands of data are generated. When displayed, they produce a natural color image covering the entire earth. Library of Congress Catalog Card No. 95-71100 International Standard Book No. 0-309-05345-5 Copies of the report are available from: National Academy Press , 2101 Constitution Avenue, NW, Washington, DC, 20055, 800-624-6242, 202-334-3313 (In the Washington Metropolitan Area) B-677. Copyright 1996 by the National Academy of Sciences. All rights reserved. Printed in the United States of America
iii COMMITTEE ON THE BERING SEA ECOSYSTEM ROBERT C. FRANCIS, Chair, University of Washington, Seattle LEE G. ANDERSON, University of Delaware, Newark W.D. BOWEN, Bedford Institute of Oceanography, Dartmouth, Nova Scotia, Canada STEVEN K. DAVIS, LGL Alaska Research Associates, Anchorage JACQUELINE M. GREBMEIER, University of Tennessee, Knoxville LLOYD F. LOWRY, Alaska Department of Fish and Game, Fairbanks ILARIAN MERCULIEFF, City of St. Paul, St. Paul Island, Alaska (through 12/2/93) NATALIA S. MIROVITSKAYA, Russia Academy of Sciences, Moscow CHARLES H. PETERSON, University of North Carolina, Chapel Hill, Morehead City CALEB PUNGOWIYI, Inuit Circumpolar Conference, Anchorage THOMAS C. ROYER, University of Alaska, Fairbanks ALAN M. SPRINGER, University of Alaska, Fairbanks WARREN S. WOOSTER, University of Washington, Seattle NRC Staff CHRIS ELFRING, PRB Director LOREN W. SETLOW, PRB Director (through 10/95) DAVID J. POLICANSKY, Study Director KELLY NORSINGLE, Senior Project Assistant
iv POLAR RESEARCH BOARD DAVID L. CLARK, Chair, University of Wisconsin, Madison KNUT AAGAARD, University of Washington, Seattle JOHN B. ANDERSON, Rice University, Houston, Texas DAVID R. BAINES, St. Maries Clinic, St. Maries, Idaho ERNEST S. BURCH, Jr., Consultant, Camp Hill, Pennsylvania GORDON F.N. COX, Amoco Production Company, Houston, Texas ROBERT L. DEZAFRA, State University of New York, Stony Brook BERNARD HALLET, University of Washington, Seattle DOYAL A. HARPER, Yerkes Observatory, Williams Bay, Wisconsin DAVID M. HITE, Consultant, Anchorage, Alaska JUNE LINDSTEDT-SIVA, ARCO, Los Angeles, California DIANNE M. MCKNIGHT, U.S. Geological Survey, Boulder, Colorado DOYAL T. MANAHAN, University of Southern California, Los Angeles WALTER C. OECHEL, San Diego State University, San Diego, California IRENE C. PEDEN, University of Washington, Seattle GLENN E. SHAW, University of Alaska, Fairbanks DONALD B. SINIFF, University of Minnesota, St. Paul ROBERT M. WALKER, Washington University, St. Louis, Missouri Ex-Officio Members CHARLES R. BENTLEY, University of Wisconsin, Madison ELLEN S. MOSLEY-THOMPSON, Ohio State University, Columbus ROBERT H. RUTFORD, University of Texas, Dallas ORAN R. YOUNG, Dartmouth College, Hanover, New Hampshire NRC Staff CHRIS ELFRING, Director LOREN W. SETLOW, Director (through 10/95) TONI GREENLEAF, Senior Project Assistant/Financial Assistant KELLY NORSINGLE, Senior Project Assistant
v COMMISSION ON GEOSCIENCES, ENVIRONMENT, AND RESOURCES M. GORDON WOLMAN, Chairman, The Johns Hopkins University, Baltimore, Maryland PATRICK R. ATKINS, Aluminum Company of America, Pittsburgh, Pennsylvania JAMES P. BRUCE, Canadian Climate Program Board, Ottawa WILLIAM L. FISHER, University of Texas at Austin JERRY F. FRANKLIN, University of Washington, Seattle GEORGE M. HORNBERGER, University of Virginia, Charlottesville DEBRA KNOPMAN, Progressive Foundation, Washington, D.C. PERRY L. MCCARTY, Stanford University, California JUDITH E. MCDOWELL, Woods Hole Oceanographic Institution, Massachusetts S. GEORGE PHILANDER, Princeton University, New Jersey RAYMOND A. PRICE, Queen's University at Kingston, Ontario THOMAS C. SCHELLING, University of Maryland, College Park ELLEN SILBERGELD, University of Maryland Medical School, Baltimore STEVEN M. STANLEY, The Johns Hopkins University, Baltimore, Maryland VICTORIA, J. TSCHINKEL, Landers and Parsons, Tallahassee, Florida NRC Staff STEPHEN RATTIEN, Executive Director STEPHEN D. PARKER, Associate Executive Director MORGAN GOPNIK, Assistant Executive Director GREGORY SYMMES, Reports Officer JAMES E. MALLORY, Administrative Officer SANDRA S. FITZPATRICK, Administrative Associate SUSAN SHERWIN, Project Assistant
PREFACE vi Preface The plentiful fish and game of the Bering Sea have supported the lives and livelihood of people on both the Asian and the North American continents since prehistoric times. The Bering Sea is a subarctic, semi-enclosed northern extension of the North Pacific Ocean; its southern boundary is marked by the Aleutian Islands and its northern boundary by Bering Strait. Its wide variety of fish, shellfish, birds, and mammals both in coastal areas and offshore provided an incentive for small population centers to be established in what is now Russia and the United States. As the world's demand for furs and whale oil grew in the eighteenth and nineteenth centuries, exploitation of the Bering Sea's bountiful living resources began on a commercial scale. During the twentieth century, international markets turned to the Bering Sea for its seafood resources. Legal protections for marine mammals were developed in recent decades, and the taking of them declined significantly. Today, approximately 25 species of fish, crustaceans, and mollusks of the Bering Sea are considered important commercially. Despite the protection for marine mammals, birds, and fish resources afforded by laws of the United States and Russia, and joint treaties between these two nations, some species of the Bering Sea and adjacent regions have undergone large and sometimes sudden population fluctuations. For example, Steller sea lions have declined by 50 to 80 percent and northern fur seal pups on the Pribilof Islands (the major Bering Sea rookeries) declined by 50 percent between the 1950s and 1980s. In parts of the Gulf of Alaska, harbor seal numbers have dropped by as much as 90 percent since the 1970s. Populations of seabirds such as common murres, thick-billed murres, and red-legged and black-legged kittiwakes have also declined significantly in some areas such as the Pribilof Islands and the eastern Aleutians. These changes have raised concerns about how living resources in the area have been and should be managed. Although many suggestions have been put forward as to the factors responsible for these wildlife population fluctuations, there have been no definitive answers. Concerned about the future of the Bering Sea ecosystem, the U.S. Department of State asked the National Research Council (NRC) to study the available scientific and technical information on the Bering Sea ecosystem, focusing, in particular, on environmental factors that influence natural variability in populations of marine mammals, seabirds, and fish. The U.S.
PREFACE vii Coast Guard joined in supporting this project because of its role in scientific research, rescue, and law enforcement in U.S. waters, particularly the Bering Sea. To respond to the charge, the National Research Council's Polar Research Board established the Committee on the Bering Sea Ecosystem. The charge to the study committee was to review and evaluate the following: â¢ Environmental factors and ecological relationships that control the Bering Sea ecosystem, including atmospheric and ocean circulation patterns, biological production pathways, and energy transfer within the food web. â¢ The life history, distribution, and population dynamics of commercially important species, with special emphasis on species that migrate through international waters or into the United States or Russian exclusive economic zones; and the probable causes and effects of their population fluctuations. â¢ Estimates of historical population dynamics of marine mammals, seabirds, and commercially important species of the Bering Sea, their interrelationships, their current status, and the factors contributing to their population fluctuations. â¢ The historical records of the commercial fisheries of the Bering Sea. â¢ The relationship between the biological resources of the Bering Sea and (a) subsistence cultures and economies of indigenous peoples, (b) commercial fisheries and other users, and (c) the assemblage of organisms that constitute the biological component of the Bering Sea ecosystem. To execute this charge, the committee met five times to gather information and deliberate on issues. We read many reports, published papers, and other documents. At its meetings in Anchorage and Seattle, the committee was briefed by the National Marine Fisheries Service, environmental organizations, the U.S. North Pacific fishing industry, Native American organizations, the Japanese Ministry of Fisheries, the U.S. Coast Guard, the North Pacific Fishery Management Council, the Russian Academy of Sciences, the Smithsonian Institution, and other organizations and individuals. The committee is most grateful to these people and organizations (see Appendix B). The committee members approached their task with many varying views but with open minds. None of us foresaw the conclusions we reached and unanimously agreed to, and we all learned a great deal from each other and from this study. I am pleased that our conclusions agree with some aspects of U.S. arctic policy as reflected in recent policy statements, in particular the importance of sustainable resource management and economic development, the need to strengthen institutional cooperation among arctic nations, the importance of an integrated research program, and the importance of involving indigenous peoples in decisions concerning them. My experience on this committee in particular brought home to me the need to develop ways to overcome the difficulties of meaningfully bridging the deep differences between indigenous and western cultures. This report is the result of the committee's hard work and deliberations and the PRB staff's valuable support. Thanks are due to both for the tremendous effort they put forth to
PREFACE viii bring this work to conclusion. The diversity of backgrounds and intellectual focus brought to the issue at hand made this an enjoyable and edifying experience as well. Finally, I wish to thank two outstanding individuals who have helped make my task much easier. Kelly Norsingle took care of most of the logistics, facilitation, and report preparation, andâmore importantlyâshe was always there with an effervescent and helping attitude to the task at hand. To me, she defines the term "service excellence." And last but certainly not least, David Policansky has not only supported my efforts to make this report a quality one, he has patiently and persistently guided me along the path of this long and difficult journey. Robert C. Francis, Chair, Committee on the Bering Sea Ecosystem
CONTENTS ix Contents Executive Summary 1 1 Introduction 7 The Problem 8 The Study 9 2 Marine Ecosystems: A Conceptual Framework 11 Conceptual Framework 11 Oceanic and Terrestrial Ecosystems 16 Environmental and Anthropogenic Forcing 17 The Condition of an Ecosystem 20 Ecosystem Management 20 The Bering Sea Ecosystem and its Analogs 24 The Delineation of Bering Sea Ecosystem 25 3 The Bering Sea Ecosystem: Geology, Physics, Chemistry, Biology 28 Marine Geology 28 Physical Oceanographic Structure 35 Primary and Secondary Production 54 Biology of Lower Trophic Levels 60 4 Biology of Higher Trophic Levels 72 Invertebrates 72 Finfish 79 Birds 110 Marine Mammals 126 Discussion of Population Declines 139
CONTENTS x 5 Human UseâFisheries 156 Fish and Invertebrates 156 Marine Mammals (and Birds) 180 Interactions of Indigenous Populations with Marine Ecosystems 183 6 Causes and Effects in the Bering Sea Ecosystem 196 Environmental Variability 197 Human Effects 207 The ''Cascade Hypothesis" and the Bering Sea Ecosystem 218 Discussion 232 Conclusions 234 7 Implications for Management Policy & Institutional Arrangements 238 The Bering Sea Ecosystem As An Asset 239 Implications for Management 242 8 Gaps in Knowledge and Recommendations 250 Recommendations 255 The Future 259 References 260 Appendixes A Biographical Sketches of the Committee Members 304 B Contributors 306