Marine Survival of Puget Sound Coho Salmon: Deciphering the Climate Signal

1999 ◽  
Author(s):  
W.D. Pinnix
Keyword(s):  
Coho Salmon ◽  
Puget Sound ◽  
Climate Signal ◽  
Marine Survival

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

2017 ◽  
Vol 45 (3) ◽  
pp. 278-290 ◽  
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.

Experimental Management of Oregon Coho Salmon (Oncorhynchus kisutch): Designing for Yield of Information

1983 ◽  
Vol 40 (8) ◽  
pp. 1212-1223 ◽  
Author(s):  
Randall M. Peterman ◽  
Richard D. Routledge
Keyword(s):  
Statistical Power ◽  
Large Scale ◽  
Coho Salmon ◽  
Experimental Manipulation ◽  
Analytical Approximation ◽  
Large Variability ◽  
Power Of The Test ◽  
Marine Survival ◽  
Experimental Management ◽  
Experimental Release

Large-scale experimental manipulation of juvenile salmon (Oncorhynchus spp.) abundance can provide a test of the hypothesis of linearity in the smolt-to-adult abundance relation. However, not all manipulations will be equally informative owing to large variability in marine survival. We use Monte Carlo simulation and an analytical approximation to calculate for Oregon coho salmon (O. kisutch) the statistical power of the test involving different controlled smolt abundances and durations of experiments. One recently proposed experimental release of 48 million smolts for each of 3 yr has a relatively low power and, as a consequence, is unlikely to show clearly whether the smolt-to-adult relationship is linear. The number of smolts required for a powerful test of the hypothesis of linearity is closer to the 88 million suggested in another proposal. To prevent confounding of interpretation of results, all other human sources of variability in fish should be minimized by establishing standardized rearing and release procedures during the experiment. In addition, appropriate preexperiment data on coho food, predators, and competitors will increase effectiveness of experiments by providing information on mechanisms of change in marine survival.

Importance of Smolt Size and Early Ocean Growth to Interannual Variability in Marine Survival of Coho Salmon (Oncorhynchus kisutch)

1990 ◽  
Vol 47 (11) ◽  
pp. 2181-2194 ◽  
Author(s):  
L. Blair Holtby ◽  
Bruce C. Andersen ◽  
Ronald K. Kadowaki
Keyword(s):  
Interannual Variability ◽  
Coho Salmon ◽  
Age Groups ◽  
Oncorhynchus Kisutch ◽  
Northwest Coast ◽  
Size Distributions ◽  
Strongly Correlated ◽  
Large Size ◽  
Ocean Conditions ◽  
Marine Survival

The importance of smolt size and early ocean growth to the marine survival of coho salmon was examined over a 17-yr period at Carnation Creek, British Columbia. Comparisons of overall marine survival were made both between-years, using two smolt age-groups of different mean sizes, and within-years using observed smolt size distributions and smolt size distributions back-calculated from the scales of returning adults. Large size did not confer a consistent survival advantage but large smolts did survive better in years when marine survival was relatively poor. Marine survivals were strongly correlated with early ocean growth as estimated by the spacing of the first five ocean circuli on the scales of returning adults. Marine survival and early ocean growth were positively correlated with ocean conditions indicative of strong upwelling along the northwest coast of Vancouver Island. Neither smolt survival nor early ocean growth were correlated with regional coho smolt production. Our observations suggest that interannual variability in smolt survival was being driven by ocean conditions that determined smolt growth rates which subsequently affected the susceptibility of smolts to a size-selective predator.

Comparing abundance-based and tag-based estimates of coho salmon marine survival

2019 ◽  
Vol 26 (2) ◽  
pp. 165-171
Author(s):  
Sean M. Cochran ◽  
Seth Ricker ◽  
Colin Anderson ◽  
Sean P. Gallagher ◽  
Darren M. Ward
Keyword(s):  
Coho Salmon ◽  
Marine Survival

Environmental factors influencing freshwater survival and smolt production in Pacific Northwest coho salmon (Oncorhynchus kisutch)

2004 ◽  
Vol 61 (3) ◽  
pp. 360-373 ◽  
Author(s):  
P W Lawson ◽  
E A Logerwell ◽  
N J Mantua ◽  
R C Francis ◽  
V N Agostini
Keyword(s):  
Pacific Northwest ◽  
Air Temperature ◽  
Coho Salmon ◽  
Oncorhynchus Kisutch ◽  
Stream Flows ◽  
Factors Influencing ◽  
Life Phase ◽  
Air Temperatures ◽  
Queets River ◽  
Marine Survival

Climate variability is well known to affect the marine survival of coho salmon (Oncorhynchus kisutch) in Oregon and Washington. Marine factors have been used to explain up to 83% of the variability in Oregon coastal natural coho salmon recruitment, yet about half the variability in coho salmon recruitment comes from the freshwater life phase of the life cycle. This seeming paradox could be resolved if freshwater variability were linked to climate and climate factors influencing marine survival were correlated with those affecting freshwater survival. Effects of climate on broad-scale fluctuations in freshwater survival or production are not well known. We examined the influence of seasonal stream flows and air temperature on freshwater survival and production of two stock units: Oregon coastal natural coho salmon and Queets River coho salmon from the Washington Coast. Annual air temperatures and second winter flows correlated strongly with smolt production from both stock units. Additional correlates for the Oregon Coast stocks were the date of first fall freshets and flow during smolt outmigration. Air temperature is correlated with sea surface temperature and timing of the spring transition so that good freshwater conditions are typically associated with good marine conditions.

Factors Affecting Partial Migration in Puget Sound Coho Salmon

2014 ◽  
Vol 34 (3) ◽  
pp. 559-570 ◽  
Author(s):  
Jessica Rohde ◽  
Kurt L. Fresh ◽  
Thomas P. Quinn
Keyword(s):  
Coho Salmon ◽  
Puget Sound ◽  
Partial Migration ◽  
Factors Affecting

Natural Mortality Rate in Last Winter of Life of Coho Salmon (Oncorhynchus kisutch) Resident in Puget Sound

1974 ◽  
Vol 31 (6) ◽  
pp. 1158-1160 ◽  
Author(s):  
Stephen B. Mathews ◽  
Raymond Buckley
Keyword(s):  
Mortality Rate ◽  
Coho Salmon ◽  
Puget Sound ◽  
Oncorhynchus Kisutch ◽  
Fork Length ◽  
Natural Mortality

The natural mortality rate during a 3.5-mo period of the last year of life of coho salmon (Oncorhynchus kisutch) resident in Puget Sound was estimated to be 48% of the population at the beginning of this period. This estimate was based on recaptures of 29 fish out of 169, averaging 32 cm in fork length, tagged in January and early February, and 20 out of 61 averaging 41 cm tagged in May and early June, 1970.

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