The Offshore Habitat Working Group had an open and informative discussion about problems and research related to oceanic growth and survival of salmon. There was general agreement that considerably more time, effort, and thought are needed to adequately address the objectives outlined in the workshop guidelines. The group identified and discussed some important questions and hypotheses, which are listed below, but emphasized that these results are not prioritized or conclusive. The group decided that its most important task during the meeting would be to present a list of research recommendations to all attendees in the final session prior to adjournment. The group agreed that after the meeting the Chairman would circulate a draft of the results among the participants for review. These reviews are incorporated into the final section of this report.

1. What are the distribution and migration patterns of salmon at sea? How do currents and other physical factors influence distribution and migration patterns? (Possible research strategies involve modeling and tagging, integrated with food studies.)

2. What triggers a change in life history stage (e.g., inshore-offshore, immature-maturing)?

   
   Five associated questions about growth, maturation, fecundity, and survival are

3. What are the relationships between physical forcing and ocean growth and survival?

4. What causes regime-scale changes in survival?

5. What causes long-term changes in growth, maturity, and reproductive potential?

6. What is the role of the ocean in determining fecundity and lipid stores, size-at-age, age-of-maturity, and viability of eggs?

7. How does salmon growth vary across species, space, time, etc., and what are the causes of variability in growth of salmon?
   

   
   One question about forecasting of adult returns is

8. Can ocean-salmon-catch data be used to forecast adult returns?

H₁

Physical forcing affects the oceanic distribution of salmon.

H₂

Offshore migration patterns of salmon are genetically determined.

H₃

Migration paths are selected to optimize growth/production, minimize energetic losses, or, perhaps, minimize the ratio of mortality:growth.

H₄

Distribution of forage affects oceanic distribution of salmon.

H₅

Maturation in salmon is triggered when some lipid threshold is exceeded.

H₆

Marine survival (recruitment) is determined by events in the coastal zone.

H₇

Final size is determined in the oceanic (offshore) zone.

H₈

There is a positive functional relationship between growth and survival.

H₉

Growth, age of maturing, fecundity, and reproduction potential are density dependent in the oceanic zone.

H₁₀

Annual stock-specific salmon growth is stationary over time.

H₁₁

Annual stock-specific growth varies interdecadally or shows regime-scale trends.

H₁₂

Growth of Alaska salmonids is inversely related to growth of U.S. West Coast stocks.

1. An integrated, coastwide commitment to a long-term fishery-oceanographic monitoring program in the northeastern Pacific is needed.

   The working group envisioned a multidisciplinary scientific research effort, tied to the practical need for better assessment and management of valuable marine resources, that would benefit a variety of species, programs, and agencies. The program would establish a sequence of monitoring lines in the North Pacific (e.g., p hydrologic line off Kodiak Island, Seward line, Papa line, Newport line, and CALCOFI Line 60 off San Francisco) for collection of both surface and subsurface data. Perhaps one vessel would be committed to a basic minimum monitoring program to maintain these lines, but the entire package would include a mix of surface buoys, moorings, ships, and satellites and other remote sensing devices. This multidisciplinary effort requires a long-term commitment, and this commitment must include all aspects of the research, not just the simple physical monitoring. The development of this program and sampling protocols would require extensive coordination with Global Ocean Ecosystem Dynamics Program (GLOBEC), National Oceanic and Atmospheric Administration, Canada's Department of Fisheries and Oceans, and other organizations.

2. Assumptions about ocean distribution and migration patterns must be validated.

   There is a need for fundamental biological information on salmon distribution and migration patterns. New techniques (e.g., smart tags) can be used to determine behavioral responses to temperature and other environmental factors and swimming depths, and also as a tool to verify computer models. Stock identification using a variety of methods (e.g., tags, electrophoresis, DNA, scales, and otolith marks) is important to understanding the relationships among distribution, migration patterns, and ocean survival.

3. Interaction among stocks is a key issue that needs to be investigated.

4. Research should focus on weight and energy content of salmon, not just mean lengths or abundance.

5. There should be continued emphasis on the use of scales in studies of ocean growth. A scale workshop coordinated by PICES (an international North Pacific marine science organization) and NPAFC (North Pacific Anadromous Fish Commission) is needed immediately.

6. Better field estimates of feeding and stomach evacuation rates (24-hour sampling) and more comprehensive studies (acoustic and net sampling) of prey species, especially fish and squids, are needed.
   

   There is a need to standardize gear and sampling techniques used in prey studies. Zooplankton data are only a surrogate in areas where salmon are feeding primarily on fish and squid. Most zooplankton gear does not catch small- to medium-sized pelagic squids and similar-sized forage fishes. There may be a need to develop or modify existing gear (e.g., larger mouth opening for trawls) for sampling squid. Neuston collections should be added to the standard array of forage sampling in the areas over the continental shelf and near shore, as smaller outmigrant salmon are surface oriented and feed on items in the neuston. The importance of neuston to salmonids on the high seas still needs investigation.

7. There needs to be a better balance between "top-down" and "bottom-up" approaches in the study of ocean survival.

   Research should focus on predators, competitors, and disease organisms. We should be looking at associated communities and the variability in survival due to predation. In particular, more research on the distribution and abundance of predators and predation rates is needed. Because of the lack of data, we may have to start with "back-of-the-envelope" calculations. Research strategies could involve the use of isotope analyses combined with natural chemical tracers to determine food webs. Methods to study disease, competition, and predation need to be designed. All life history stages need to be examined.

8. Research should focus on key stocks (e.g., Bristol Bay sockeye salmon, Prince William Sound pink salmon, Fraser River sockeye salmon, Columbia River chinook salmon, Oregon Production Index coho salmon, and Sacramento River chinook salmon).

9. Working groups to coordinate research efforts should be convened more frequently than every 13 years.

10. There is a need for coordination of acquisition and assimilation of databases, leading, perhaps, to the development of a World Wide Web site to facilitate communication between investigators as well as to serve as a clearinghouse of archived data useful for the study of high-seas salmon.

    The group discussed some of the databases critical for this work: 1) inshore salmon catch and escapement data, 2) scale archives, 3) offshore catch and biological data on both salmonids and associated species, and 4) oceanographic data.

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