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U.S. Dept Commerce/NOAA/NMFS/NWFSC/Tech Memos

NOAA Technical Memorandum NMFS-NWFSC-29

Estuarine and Ocean Survival
of Northeastern Pacific Salmon

Proceedings of the Workshop
March 20-22, 1996
Newport, Oregon

Edited by
Robert L. Emmett and Michael H. Schiewe

National Marine Fisheries Service
Northwest Fisheries Science Center
Coastal Zone and Estuarine Studies Division
2725 Montlake Blvd. E.
Seattle WA 98112-2097
(206) 860-3270

April 1997

William Daley, Secretary

National Oceanic and Atmospheric Administration
D. James Baker, Administrator

National Marine Fisheries Service
Rolland A. Schmitten, Assistant Administrator for Fisheries

NOAA-NWFSC Tech Memo-29: Estuarine and Ocean Survival of Northeastern Pacific Salmon

NOAA Technical Memorandum NMFS Series

The Northwest Fisheries Science Center of the National Marine Fisheries Service, NOAA, uses the NOAA Technical Memorandum NMFS series to issue informal scientific and technical publications when complete formal review and editorial processing are not appropriate or feasible due to time constraints. Documents published in this series may be referenced in the scientific and technical literature.

The NMFS-NWFSC Technical Memorandum series of the Northwest Fisheries Science Center continues the NMFS-F/NWC series established in 1970 by the Northwest & Alaska Fisheries Science Center, which has since been split into the Northwest Fisheries Science Center and the Alaska Fisheries Science Center. The NMFS-AFSC Technical Memorandum series is now being used by the Alaska Fisheries Science Center.

Reference throughout this document to trade names does not imply endorsement by the National Marine Fisheries Service, NOAA.

This document should be cited as follows:

Emmett, R.L., and M.H. Schiewe (editors). 1997. Estuarine and ocean survival of Northeastern Pacific salmon: Proceedings of the workshop. U.S. Dep. Commer., NOAA Tech. Memo. NMFS-NWFSC-29, 313 p.

This document is available to the public through:

National Technical Information Service
U.S. Department of Commerce
5285 Port Royal Road
Springfield, VA 22161

Table of Contents

Preface. R.L. Emmett and M.H. Schiewe

Welcome. U. Varanasi

Keynote Address: Salmon Oceanography? W.S. Wooster

Special Topics in Salmonid Life Histories

Changes in Ocean Survival of Coho and Chinook Salmon in the Pacific Northwest. R. Hilborn and C. Coronado Partitioning Mortality in Pacific Salmon. M.J. Bradford Geographical Variation in Life Histories of Salmonids. L. Weitkamp, P. Busby, and K. Neely Factors Influencing Freshwater and Marine Survival of Oregon's Coastal Coho Salmon—What We Know and What We Don't. S. Johnson Decadal Scale Climate Pattern and Salmon Survival: Indicators, Interactions, and Implications. J.J. Anderson

Interannual Variations in Northeast Pacific Marine Habitats and the Effects on Marine Survival of Salmonids

Coastal Ocean Circulation Off Oregon: Recent Observations of Spatial and Temporal Variability. J.A. Barth and R.L. Smith The Food Environment of Juvenile Salmonids: Year-to-Year Variations in Zooplankton Abundance Over the Inner-middle Shelf Off Central Oregon—1969-78. W.T. Peterson Interannual Variability in Growth and Survival of Chinook and Coho Salmon. P.W. Lawson

Decadal Variations in Northeast Pacific Marine Habitats and the Effects on Marine Survival of Salmonids

Regime-scale Fluctuations in the Circulation of the North Pacific. R.H. Parrish Decadal-scale Environmental Variability in the Coastal Northeastern Pacific. F.B. Schwing, R. Parrish, and R. Mendelssohn Regime Scale Climate Forcing of Salmon Populations in the Northeast Pacific—Some New Thoughts and Findings. R.C. Francis and S.R. Hare

Process and Mechanisms—Estuarine

The Relationship of Estuarine Primary and Secondary Productivity to Salmonid Production: Bottleneck or Window of Opportunity? C.A. Simenstad Estuarine Survival of Salmonids: the Importance of Interspecific and Intraspecific Predations and Competition. R.L. Emmett Criteria for Evaluating the Survival Value of Estuaries for Salmonids. C.D. Levings and D. Bouillon Estuarine Pollution and Juvenile Salmon Health: Potential Impact on Survival. E. Casillas, B.B. McCain, M. Arkoosh, and J.E. Stein

Process and Mechanisms—Nearshore Coastal

Factors Influencing the Marine Survival of Pink Salmon in Prince William Sound, Alaska. R.T. Cooney and T.M. Willette The Importance of Various Spatial and Temporal Scales in the Interaction of Juvenile Salmon and the Marine Environment. R.D. Brodeur Climate-Ocean Changes and the Impacts on Young Salmon in the Strait of Georgia. R.J. Beamish and C. Neville Early Ocean Survival of Salmon Off British Columbia and Impacts of the 1983 and 1991-95 El Niño Events. B.N. Hargreaves

Process and Mechanisms—Offshore Marine

Offshore Distribution and Migration Patterns and Ocean Survival of Salmon. K.W. Myers Modeling Temporal and Spatial patterns of Salmon Migration, Feedings, and Growth in the Northeast Pacific Ocean. P.S. Rand, J.P. Scandol, and S.G. Hinch Patterns of Covariation in Components of Recruitment Among Sockeye Salmon Stocks in British Columbia and Alaska. R.M. Peterman, B.J. Pyper, M.F. Lapointe, and M.D. Adkison Growth and Energetics of Salmon in the Sea. D.W. Welch

Working Groups

Working Groups Kickoff Address: What Have We Learned in the Last Decade? What Are Research Priorities? W.G. Pearcy Report of Working Group on Partitioning Survival. Chair: M. Bradford. Rapporteur: C. Levings. Report of Working Group on Estuarine Habitat Problems and Research. Chair: R. Emmett. Rapporteur: B. McCain Report of Working Group on Nearshore Habitats. Chair: W.T. Peterson. Rapporteur: R.D. Brodeur Report of Working Group on Offshore Habitat Problems and Research. Chair: Katherine Myers. Rapporteur: Steve Ignell Post-Workshop Reviews

List of Attendees with Photo


It has been 13 years since the last conference on biotic and abiotic factors affecting oceanic and estuarine survival of salmon. The proceedings from that meeting, "The Influence of Ocean Conditions on the Production of Salmonids in the North Pacific," edited by William Pearcy (1983), summarized existing information linking oceanic conditions and salmonid survival, distribution, and abundance. All four work groups at the 1983 meeting emphasized the need to understand the effects of ocean conditions on salmonid survival, and called for long-term studies of the marine environment.

Unfortunately, the recommendations from the 1983 meeting have gone largely unheeded. Although the salmon research community has continued to spend large amounts of time and funding on freshwater habitat issues, relatively little has been spent on estuarine and marine salmonid habitat issues. In the meantime, Northwest salmon populations have continued to decline, with "poor" ocean conditions often being acknowledged as playing some ill-defined role.

In an effort to once again highlight the importance of estuarine and oceanic residency to salmon survival and year-class strength, we convened a small group in the summer of 1995 to begin planning a workshop to bring together scientists whose research addresses some aspect of this important issue. Providing further impetus to our efforts were several recent reports, including the National Research Council's "Upstream: Salmon and Society in the Pacific Northwest" (1996) and the Snake River Salmon Recovery Team's "Final Recommendations for the National Marine Fisheries Service," which have highlighted the need to fully understand salmonid estuarine and marine life histories—not just because these environments are where salmonids spend most of their lives, but also because substantial mortalities occur there, and rigorous evaluations of freshwater salmonid enhancement projects require information on estuarine and ocean survival.

The workshop consisted of 25 presentations, organized in the following six sessions:

1) selected aspects of salmonid life histories
2) interannual variations in Northeast Pacific marine habitats and the effects on marine survival of salmonids
3) decadal variations in Northeast Pacific marine habitats and the effects on marine survival of salmonids
4) processes and mechanisms in estuarine habitats
5) processes and mechanisms in nearshore coastal habitats
6) processes and mechanisms in offshore marine habitats

On the final day of the workshop, four working groups were organized to identify and discuss critical research needs, formulate testable hypotheses, and identify potential research strategies to enhance understanding of the role of estuarine and oceanic habitats in salmonid survival. Since the four work groups met independently, their results are presented in slightly different formats.

As with any scientific meeting, the ultimate success depended largely on the thoughtful planning of the steering committee. For the 1996 Newport workshop, "Estuarine and Ocean Survival of Northeast Pacific Salmon," the steering committee was composed of Dr. George Boehlert of NMFS's Southwest Fisheries Science Center, Dr. Robert Francis of the University of Washington, Dr. Steve Ignell of NMFS's Alaska Fisheries Science Center, Dr. William Pearcy of Oregon State University, and Drs. Michael Schiewe and William Peterson, and Mr. Robert Emmett of the Northwest Fisheries Science Center. Drs. William Peterson, Richard Brodeur, Michael Bradford, Colin Levings, Steve Ignell, and Bruce McCain, and Ms. Kate Myers served as chairs and rapporteurs for the working groups. Finally, Ms. Sharon Damkaer and Dr. David Damkaer greatly assisted with compiling, editing, and reviewing the manuscripts in these proceedings.

Although it has taken 13 years to reconvene a conference on oceanic and estuarine survival of salmon, the results perhaps justify the wait. More than 140 scientists, representing disciplines ranging from fisheries ecology to population dynamics, and physical and biological oceanography to climatology, spent three intellectually stimulating days listening to papers, engaging in discussion, and planning future collaborations. To all the participants, we extend our sincere thanks.

Robert L. Emmett and Michael H. Schiewe
Northwest Fisheries Science Center


I take great pleasure in welcoming you to this conference on estuarine and ocean survival of northwestern Pacific salmon. Both the topic of this conference and its location in Newport are very significant to the Northwest Fisheries Science Center (NWFSC). I think most of you know that just a few minutes south of here is the campus of Oregon State University's Hatfield Marine Science Center. The Hatfield Center also houses laboratories of the National Marine Fisheries Service (NMFS), the Environmental Protection Agency, and the Oregon Department of Fish and Wildlife. This setting provides an ideal opportunity to undertake cooperative research programs among the federal, state, and university scientists. We began capitalizing on that potential about a year ago, when we transferred a few of our Seattle researchers to the Newport laboratory. We have also been very fortunate to hire a small number of highly qualified scientists to work on two new research programs at Newport. The first is the west coast groundfish ecology and assessment program. The second is a program to develop research strategies on estuarine and ocean survival of both marine and anadromous fishes.

I am very pleased to be here because this conference allows scientists from different institutions and different disciplines to come together to discuss important issues regarding salmon survival. I think all of you are aware of the national attention focused on the declining salmon stocks in the Pacific Northwest. The salmon problem encompasses the entire West Coast. There is a great deal of concern that we scientists are focusing considerably more attention on certain problems and not enough on others. One of the areas that requires good scientific planning and effort is the understanding of the factors that affect estuarine and ocean survival of salmon.

Salmon, in the course of their natural life cycle, originate in fresh water, pass through estuaries, adapt to salt water, and travel long distances in the ocean before returning to their natal stream to spawn. This life-history strategy is very complex and demanding for the species to maintain, as well as difficult for the scientists to study. The salmon species also has to cope with a number of natural and human-induced habitat changes. When these anthropogenic changes are superimposed on natural upheavals, they cause major impacts on salmon survival. As a result, on the West Coast where environmental and anthropogenic changes have been catastrophic, we are seeing considerable decline in many salmonid populations.

Considering all of the stresses that we are putting on salmon and their habitats, it is amazing that we still have any salmon left. Nevertheless, I believe that with a combination of dedicated scientific effort, wise environmental effort, and good management, we can mitigate at least some of the major stresses that salmon are facing. Most of the attention so far has been on the alterations in fresh water, partly because the changes are much more obvious and easier to study and correct. However, it has become very clear that we need to focus on and develop considerable information about all stages and geographic phases of the salmon life history.

The importance of this information has been emphasized in the Snake River Recovery Team recommendations, in the NMFS-proposed Snake River Salmon Recovery Plan, and in the National Research Council's report. This is the right time for us to come together. I'm very thankful to Mike Schiewe and the steering committee, who have worked for the last 6-8 months to develop this agenda and to bring you all together here. I think it is time for us to identify the areas in which we presently have a lack of information and understanding, and what actions we should undertake collectively for the next few years. So I'm looking forward to your presentations and to the directions for new research that you will recommend. I'm very pleased that NMFS is able to sponsor this conference along with our colleagues at Oregon State University — I am a strong believer in multi-disciplinary efforts to address and develop innovative research strategies.

My own experience as a scientist, working for about 20 years on marine pollution issues, has shown that success has always occurred when scientists from different disciplines come together in somewhat untraditional alliances. I hope that the people who study natural processes, those who study anthropogenic stress, those who study biology, and those who study toxicology can come together. I think this is a good opportunity to develop some innovative strategies and a collaborative plan that we can all pursue for the next few years to come.

Thank you very much.

Usha Varanasi, Ph.D.
Director, Northwest Fisheries Science Center

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