Estimating spatial–temporal differences in Chinook salmon outmigration survival with habitat- and predation-related covariates

Canadian Journal of Fisheries and Aquatic Sciences
By: , and 

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Abstract

Low survival rates of Chinook salmon (Oncorhynchus tshawytscha) smolts in California’s Central Valley have been attributed to multiple biological and physical factors, but it is not clear which factors have the largest impact. We used 5 years of acoustic telemetry data for 1709 late-fall Chinook salmon smolts to evaluate the effect of habitat- and predation-related covariates on outmigration survival through the Sacramento River. Using a Cormack–Jolly–Seber mark–recapture model, we estimated survival rates both as a function of covariates (covariate model) and as a function of river location and release year (spatial–temporal model). Our covariate model was overwhelmingly supported as the preferred model based on model selection criteria, suggesting the covariates adequately replicated spatial and temporal patterns in smolt survival. The covariates in the selected model included individual fish covariates, habitat-specific covariates, and temporally variable physical conditions. The most important covariate affecting salmon survival was flow. We describe the importance of these parameters in the context of juvenile salmon predation risk and suggest that additional research on predator distribution and density could improve model estimates.

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Publication type Article
Publication Subtype Journal Article
Title Estimating spatial–temporal differences in Chinook salmon outmigration survival with habitat- and predation-related covariates
Series title Canadian Journal of Fisheries and Aquatic Sciences
DOI 10.1139/cjfas-2018-0212
Volume 76
Issue 9
Year Published 2019
Language English
Publisher Canadian Science Publishing
Contributing office(s) Coop Res Unit Seattle
Description 13 p.
First page 1549
Last page 1561
Country United States
State California
Other Geospatial Sacramento River
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