Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 8333
Title: Assessing freshwater life stage vulnerability and population-level responses of Chinook salmon to climate change
Author: J. M. Honea, Michelle M. McClure, J. C. Jorgensen, M. Scheuerell
Publication Year: 2016
Journal: Climate Research
Keywords: climate change, endangered Chinook salmon, life cycle, vulnerability,

 We linked a set of climate, hydrology, landscape, and fish population models to estimate changes in abundance of a population of endangered stream-type Chinook salmon as their freshwater life stages responded to a warming climate. The hydrology models estimated that increases in annual air temperature and in winter precipitation would lead to increases in water temperature and changes in discharge, including higher flows during the egg incubation period and lower flows during the summer rearing period. The spatially explicit population model estimated a resulting decline of 0-7% the number of spawners with 3 of 4 global climate models leading to a decline of 4-7%. Increased water temperature during the summer spawning life stage was the most limiting among habitat variables modeled, but our modeling suggested that aggressive habitat restoration (increasing forested area and reducing impervious area) could mitigate for some spawner abundance reductions. Better links between climate changes and habitat response, including increased streambed scour due to the larger and more frequent winter high discharge events predicted by our hydrology models, would improve our ability to estimate climate effects on populations. Future limitation by elevated summer water temperature, and potentially egg-pocket scour, would be a shift from the habitat variable currently estimated to be limiting, the percentage of fine sediment around egg-pockets. Identifying such a shift demonstrates the utility of models that consider climate and integrate life stage specific habitat influences over a species¿ life cycle, thereby indicating restoration actions with the potential to benefit sensitive life stages.

Theme: Habitats to Support Sustainable Fisheries and Recovered Populations
Foci: Characterize relationships between habitat and ecosystem processes, climate variation, and the viability of organisms.