Northwest Fisheries Science Center

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Document Type: Journal Article
Center: NWFSC
Document ID: 4485
Title: Geo-referenced, abundance calibrated ocean distribution of Chinook salmon (Oncorhynchus tshawytscha) stocks across the west coast of North America
Author: M. Renee Bellinger, Michael A. Banks, Sarah J. Bates, Eric D. Crandall, John Carlos Garza, G. Sylvia, Peter W. Lawson
Publication Year: 2015
Journal: PLoS ONE
Keywords: CPUE,Chinook salmon,migration,Fishery,Genetic stock identification,Fishery Management,

 Pacific salmon (genus Oncorhynchus) forecasting models are used to estimate stock composition, abundance, and distribution for assessment of proposed fisheries impacts, but most models fail to account for variability in survival and the influence of biophysical factors on migratory distributions. In this study, ocean distribution and relative abundance of Chinook salmon (O. tshawytscha) stocks encountered in the California Current large marine ecosystem were inferred using at-sea catch per unit effort (CPUE) fisheries and genetic stock identification data. In contrast to stock distributions estimated through coded-wire-tag recoveries (typically limited to hatchery salmon), stock-specific CPUE provides information for both wild and hatchery fish. Furthermore, this metric is independent of other stocks and is easily interpreted over multiple temporal or spatial scales, in contrast to stock composition results. Using empirical data, the stock-specific CPUE and stock composition estimates were compared to identify conditions under which these two measures were maximally different. Samples and data used here were collected at-sea using a combination of retention and non-retention fishery sampling protocols. Understanding the effects of fishery sampling method on catch rates is important when using fishery-dependent data to infer relative stock abundances. A weak effect of fishery sampling method on catch rates was observed in some, but not all analyzed, cases. Novel visualizations of stock-specific ocean distribution patterns facilitate consideration of how highly refined, spatial and genetic information could be incorporated in ocean fisheries management systems and used to investigate oceanographic and biogeographic factors that influence migratory distributions of fish in the coastal ocean.

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Theme: Ecosystem Approach to Management for the California Current Large Marine Ecosystem
Foci: Characterize ecological interactions (e.g. predation, competition, parasitism, disease, etc.) within and among species to support ecosystem approach to management.