2017 Genetic Stock Composition Analysis Of Chinook Salmon Bycatch Samples From The Gulf Of Alaska Trawl Fisheries

June 05, 2017

The Gulf of Alaska (GOA) is serves as a feeding habitat for multiple brood years of Chinook salmon (Oncorhynchus tshawytscha) originating from many different localities in North America and Asia. Determining the geographic origin and stock composition of Pacific salmon caught in federally managed fisheries is essential to understanding whether fisheries management could address potential conservation concerns. This report provides genetic stock identification results for Chinook salmon Prohibited Species Catch (bycatch) samples collected in the GOA from the trawl fisheries for walleye pollock (Gadus chalcogrammus) and catcher vessel (CV) trawl fisheries for rockfish (Sebastes spp.). The National Marine Fisheries Service (NMFS) and Alaska Department of Fish and Game (ADF&G) geographical statistical areas associated with the groundfish fishery are shown in Figure 1 and are used later in the report to describe the spatial distribution of the Chinook salmon bycatch and genetic samples. All analyses used a single nucleotide polymorphism (SNP) baseline provided by ADF&G (Templin et al. 2011; Appendix 1), the same baseline used to estimate previous stock compositions of samples from the Chinook salmon bycatch of the federally managed GOA trawl fisheries (Guthrie et al. 2013, 2016-18; Guyon et al. 2014, 2015a,b; Larson et al. 2013). For additional information regarding background and methodology refer to the Chinook salmon bycatch report prepared previously for the 2008 Bering Sea trawl fishery (Guyon et al. 2010).