Ecosystem indicators of marine survival in Puget Sound steelhead trout

We used simulated magnetic displacements to test orientation preferences of juvenile steelhead trout ( Oncorhynchus mykiss ) exposed to magnetic fields existing at the northernmost and southernmost boundaries of their oceanic range. Fish reared in natural magnetic conditions distinguished between these two fields by orienting in opposite directions, with headings that would lead fish towards marine foraging grounds. However, fish reared in a spatially distorted magnetic field failed to distinguish between the experimental fields and were randomly oriented. The non-uniform field in which fish were reared is probably typical of fields that many hatchery fish encounter due to magnetic distortions associated with the infrastructure of aquaculture. Given that the reduced navigational abilities we observed could negatively influence marine survival, homing ability and hatchery efficiency, we recommend further study on the implications of rearing salmonids in unnatural magnetic fields.

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Population, habitat, and marine location effects on early marine survival and behavior of Puget Sound steelhead smolts

Ecosphere ◽

10.1002/ecs2.1834 ◽

2017 ◽

Vol 8 (5) ◽

pp. e01834 ◽

Cited By ~ 3

Author(s):

Megan E. Moore ◽

Barry A. Berejikian

Keyword(s):

Puget Sound ◽

Marine Survival ◽

And Behavior

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Rapid growth in the early marine period improves the marine survival of Chinook salmon (Oncorhynchus tshawytscha) in Puget Sound, Washington

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f10-144 ◽

2011 ◽

Vol 68 (2) ◽

pp. 232-240 ◽

Cited By ~ 105

Author(s):

Elisabeth J Duffy ◽

David A Beauchamp

Keyword(s):

Body Size ◽

Chinook Salmon ◽

Oncorhynchus Tshawytscha ◽

Puget Sound ◽

Fork Length ◽

Adult Survival ◽

Local Conditions ◽

Size Dependent ◽

Marine Survival ◽

Growing Conditions

We examined the effect of early marine entry timing and body size on the marine (smolt-to-adult) survival of Puget Sound Chinook salmon ( Oncorhynchus tshawytscha ). We used data from coded wire tag release groups of hatchery Chinook salmon to test whether hatchery release date, release size, and size in offshore waters in July and September influenced marine survival. Marine survival was most strongly related to the average body size in July, with larger sizes associated with higher survivals. This relationship was consistent over multiple years (1997–2002), suggesting that mortality after July is strongly size-dependent. Release size and date only slightly improved this relationship, whereas size in September showed little relationship to marine survival. Specifically, fish that experienced the highest marine survivals were released before 25 May and were larger than 17 g (or 120 mm fork length) by July. Our findings highlight the importance of local conditions in Puget Sound (Washington, USA) during the spring and summer, and suggest that declines in marine survival since the 1980s may have been caused by reductions in the quality of feeding and growing conditions during early marine life.

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A hypothesis-driven statistical approach for identifying ecosystem indicators of coho and Chinook salmon marine survival

Ecological Indicators ◽

10.1016/j.ecolind.2021.107403 ◽

2021 ◽

Vol 124 ◽

pp. 107403

Author(s):

Kathryn L. Sobocinski ◽

Correigh M. Greene ◽

Joseph H. Anderson ◽

Neala W. Kendall ◽

Michael W. Schmidt ◽

...

Keyword(s):

Chinook Salmon ◽

Statistical Approach ◽

Ecosystem Indicators ◽

Marine Survival

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Using a qualitative model to explore the impacts of ecosystem and anthropogenic drivers upon declining marine survival in Pacific salmon

Environmental Conservation ◽

10.1017/s0376892917000509 ◽

2017 ◽

Vol 45 (3) ◽

pp. 278-290 ◽

Cited By ~ 6

Author(s):

KATHRYN L. SOBOCINSKI ◽

CORREIGH M. GREENE ◽

MICHAEL W. SCHMIDT

Keyword(s):

Primary Production ◽

Food Web ◽

Oncorhynchus Tshawytscha ◽

Coho Salmon ◽

Pacific Salmon ◽

Anthropogenic Impacts ◽

Puget Sound ◽

Potential Contribution ◽

Network Modelling ◽

Marine Survival

SUMMARYCoho salmon (Oncorhynchus kisutch), Chinook salmon (Oncorhynchus tshawytscha) and steelhead (Oncorhynchus mykiss) in Puget Sound and the Strait of Georgia have exhibited declines in marine survival over the last 40 years. While the cause of these declines is unknown, multiple factors, acting cumulatively or synergistically, have likely contributed. To evaluate the potential contribution of a broad suite of drivers on salmon survival, we used qualitative network modelling (QNM). QNM is a conceptually based tool that uses networks with specified relationships between the variables. In a simulation framework, linkages are weighted and then the models are subjected to user-specified perturbations. Our network had 33 variables, including: environmental and oceanographic drivers (e.g., temperature and precipitation), primary production variables, food web components from zooplankton to predators and anthropogenic impacts (e.g., habitat loss and hatcheries). We included salmon traits (survival, abundance, residence time, fitness and size) as response variables. We invoked perturbations to each node and to suites of drivers and evaluated the responses of these variables. The model showed that anthropogenic impacts resulted in the strongest negative responses in salmon survival and abundance. Additionally, feedbacks through the food web were strong, beginning with primary production, suggesting that several food web variables may be important in mediating effects on salmon survival within the system. With this model, we were able to compare the relative influence of multiple drivers on salmon survival.

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Is solar radiation responsible for declines in marine survival rates of anadromous salmonids that rear in small streams?

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f98-203 ◽

1998 ◽

Vol 55 (12) ◽

pp. 2533-2538 ◽

Cited By ~ 26

Author(s):

Carl Walters ◽

Bruce Ward

Keyword(s):

Solar Radiation ◽

Atlantic Salmon ◽

Oncorhynchus Mykiss ◽

Salmo Salar ◽

Chinook Salmon ◽

Coho Salmon ◽

Survival Rates ◽

Steelhead Trout ◽

Small Streams ◽

Marine Survival

There have been profound declines in marine survival rates of steelhead trout (Oncorhynchus mykiss), coho salmon (O. kisutch), chinook salmon (O. tschawytscha), and Atlantic salmon (Salmo salar) since the mid-1980s, and these declines have been particularly acute in sunny regions. We suggest that the problem may originate in freshwater with radiation (e.g., UV-B) damage to metabolic machinery that is expressed during stressful periods of smolting and ocean entry and that progressively worse damage may soon appear as reduction in freshwater survivals as well. This hypothesis can be tested quickly by management agencies by comparing survival rates of hatchery-reared fish with and without radiation protection during rearing.

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Rapid discovery of SNPs that differentiate hatchery steelhead trout from ESA-listed natural-origin steelhead trout using a 57K SNP array

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/cjfas-2017-0116 ◽

2018 ◽

Vol 75 (7) ◽

pp. 1160-1168 ◽

Cited By ~ 3

Author(s):

Wesley A. Larson ◽

Yniv Palti ◽

Gunagtu Gao ◽

Kenneth I. Warheit ◽

James E. Seeb

Keyword(s):

Pacific Northwest ◽

Puget Sound ◽

Snp Array ◽

Habitat Destruction ◽

Steelhead Trout ◽

Conservation Genomics ◽

Natural Origin ◽

Polymorphic Snps ◽

The Pacific ◽

Outlier Tests

Natural-origin steelhead trout (Oncorhynchus mykiss (Walbaum, 1792)) in the Pacific Northwest, USA, are threatened by a number of factors including habitat destruction, disease, decline in marine survival, and a potential erosion of genetic viability due to introgression from hatchery strains. Our major goal was to use a recently developed SNP array containing ∼57 000 SNPs to identify a subset of SNPs that differentiate hatchery and natural-origin populations. We analyzed 35 765 polymorphic SNPs in nine populations of steelhead trout sampled from Puget Sound, Washington, USA. We then conducted two outlier tests and found 360 loci that were candidates for divergent selection between hatchery and natural-origin populations (mean FCT = 0.29, maximum = 0.65) and 595 SNPs that were candidates for selection among natural-origin populations (mean FST = 0.25, maximum = 0.51). Comparisons with a linkage map revealed that two chromosomes (Omy05 and Omy25) contained significantly more outliers than other chromosomes, suggesting that regions on Omy05 and Omy25 may be of adaptive significance. Our results highlight several advantages of the 57 000 SNP array as a tool for population and conservation genomics studies.

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