Researchers within the Cooperative Institute of Marine Resources Studies at Oregon State University will continue sampling juvenile salmon, their predators, baitfish, and the physical and biological environment off the Oregon and Washington coasts.  This effort will maintain the continuity of a temporal and spatial database, that will edify the relationship between salmon abundance, distribution, growth and health with the Columbia River plume and ocean conditions off the Pacific Northwest.  Participation in research cruises will gather data on juvenile salmon abundance and distribution, size, marine growth, health and a number of biological and physical oceanographic  parameters, e.g., phytoplankton standing crop, zooplankton biomass and species composition, forage fish community, and salmonid predators.  Comparisons to previous years' data will reveal the role of interannual variability in frequency and persistence of frontal features in relationship to salmon survival.

SCIENTIFIC BACKGROUND

Recent evidence suggests that improvement in survival of the estuarine and early ocean life history phase of Columbia River salmon may be critical to recovery of endangered stocks. When coupled with evidence that the estuary and the plume (as an extension of the estuary) may be highly modified habitats due to river modifications (e.g. altered channel morphology) and modified flows as a result of the federal hydropower system, potential for achievable improvement in salmon survival from management actions seems plausible.  An understanding of which factors affect survival will require a partitioning of survival (and mortality) among freshwater, estuarine, and early ocean phases.  This in turn will require knowledge of the processes that limit and/or enhance salmon survival in these habitats.  These processes, though well characterized in the freshwater environment, have not been characterized in the estuarine and plume environment.  

GOALS

          The physical and biological factors that affect survival of juvenile salmon are known (predation by fish, birds and mammals, competition, food availability, and smolt quality and health).  However, knowledge of the mechanisms through which these factors interact to affect survival and the link to oceanographic and climatic factors is lacking.  Though it is often stated that salmon survival depends upon ‘ocean conditions', features of ‘ocean conditions' that favor or limit salmon survival remain to be empirically characterized. Moreover, the appropriate spatial and temporal scales need to be evaluated.  During the coming year, we will continue to provide estimates of growth of juvenile Chinook and Coho salmon inside and outside the Columbia River plume, and document the impact of varying ocean productivity on survival and growth rates of juvenile salmonids in the Pacific Northwest and on their prey field (euphausiids and other zooplankton species).  Documenting changes in salmonid growth, nutrient dynamics, associated fish community structure, and prey abundance (and species type) in the Columbia River plume and nearshore ocean will help identify the relationship between these factors and salmonid survival.



Element 1 - Nektonic Species Sampling - Plume and Coastal Oregon and Washington $220,582

Measure composition, distribution, and abundance of pelagic and nektonic species, including salmonids in the Columbia River plume and off coastal Oregon and Washington.

Participate in three cruises each year from Newport, Oregon to northern Washington, and 10 cruises just in the Columbia River plume.  This research will directly measure and quantify juvenile salmon abundance and distribution and provide samples to assess marine growth and health (disease) as features that can be related to physical and biological processes in the Columbia River plume and associated ocean environment.  Important marine bio/physical conditions that will be measured and compared with salmonid metrics include: 1) nutrient concentration and phytoplankton standing crop, 2) zooplankton community structure, 3) salmonid food habits and prey fields (zooplankton biomass and species composition), 4) forage fish community, and 5) salmonid predators, including large fishes, seabirds, and marine mammals.

Principle tasks include:

A. Participate in mesoscale surveys to monitor physical and biological ocean conditions and to collect fish, measure, and acquire tissue samples.

B. Participate in surveys to assess temporal and spatial distribution of piscine predators in the Columbia River Plume

C. Participate in top trophic predator studies in association with the Columbia River plume

Milestones:
Cruise #1 - Conduct trawling on a minimum of three transects, (but can be up to 8) to include Cape Meares, Columbia River, and Grays Harbor. Trawling, with a Nordic 264 surface trawl, will be at prescribed stations that start as close inshore as possible, extending at approximate 5 nautical mile increments to the shelf break. Sampling will be continued beyond the shelf break if juvenile salmon are still being captured, and as time permits. Trawls will typically be of 30-minute duration, however will be shortened if large numbers of salmon are expected. Concordant CTD casts and plankton sampling will be conducted after each trawl.  Physical features of the water will be stored on disc from the CTD for later processing.  Part of the effort will be to conduct bird observations to enumerate species and numbers. Birds represent a significant juvenile salmon predator. Bird and salmon distribution will be evaluated in analyses described in the analytical work element. Fish species, including salmon will be enumerated, and representative weights recorded. All juvenile salmon will be kept for later processing and sample disposition.

Cruise #2 - Conduct trawling on a minimum of 5 transects, (but can be up to 8) to include Newport, Cape Meares, Columbia River, Grays Harbor and La Push transects. Trawling, with a Nordic 264 surface trawl, will be at prescribe stations that start as close inshore as possible, extending at approximately 5 nautical mile increments to the shelf break. Sampling will be continued beyond the shelf break if juvenile salmon are still being captured, and as time permits. Trawls will typically be of 30-minute duration, however will be shortened if large numbers of salmon are expected. Concordant CTD casts and plankton sampling will be conducted after each trawl. Physical features of the water will be stored on disc from the CTD for later processing. Fish species, including salmon will be enumerated, and representative weights recorded. All juvenile salmon will be kept for later processing and sample disposition.

Cruise #3 - Conduct trawling on a minimum of 5transects, (but can be up to 8) to include Newport, Cape Meares, Columbia River, Grays Harbor, and La Push transects. Trawling, with a Nordic 264 surface trawl, will be at prescribed stations that start as close inshore as possible, extending at approximate 5 nautical mile increments to the shelf break. Sampling will be continued beyond the shelf break if juvenile salmon are still being captured, and as time permits. Trawls will typically be of 30-minute duration, however will be shortened if large numbers of salmon are expected. Concordant CTD casts and plankton sampling will be conducted after each trawl. Physical features of the water will be stored on disc from the CTD for later processing. Fish species, including salmon will be enumerated, and representative weights recorded. All juvenile salmon will be kept for later processing and sample disposition.

Predator Cruise - Conduct trawling on a minimum of 2transects to include Columbia River and Grays Harbor transects at night. Trawling, with a Nordic 264 surface trawl, will be at prescribed stations that start as close inshore as possible, extending at approximately 5 nautical mile increments to the shelf break. Sampling will occur at approximately 10-day intervals. Trawls will typically be of 30-minute duration, however will be shortened if large numbers of salmon are expected. Concordant CTD casts will be conducted after each trawl.  Physical features of the water will be stored on disc from the CTD for later processing.  Fish species focusing on piscine predators but including salmon will be enumerated, and representative weights recorded. All juvenile salmon will be kept for later processing and sample disposition.  Stomachs of a representative sample of piscine predators will be extracted and held for later processing in the laboratory.