Genetic Stock Composition Analysis of Chinook Salmon Bycatch Samples from the Rockfish and Arrowtooth Flounder 2013 Gulf of Alaska Trawl Fisheries and the Gulf of Alaska Salmon Excluder Device Test.

摘要

A genetic analysis of samples from the Chinook salmon (Oncorhynchus tshawytscha) bycatch of the 2013 Gulf of Alaska (GOA) trawl fisheries for Pacific rockfish (Sebastes spp.) and arrowtooth (Atheresthes stomias) flounder was undertaken to determine the stock composition of the sample sets. Samples were genotyped for 43 single nucleotide polymorphism (SNP) DNA markers and results were estimated using the Alaska Department of Fish and Game (ADF&G) SNP baseline. In 2013, genetic samples from the bycatch of the GOA rockfish fishery were collected by the fishing industry using a census sampling protocol where every Chinook salmon encountered was sampled. Based on the analysis of 2,029 Chinook salmon bycatch samples collected throughout the 2013 GOA rockfish trawl fishery, West Coast U.S. stocks (WA/OR/CA) represented the largest stock grouping (60%) with smaller contributions from British Columbia (31%), Coastal Southeast Alaska (6%), and Northwest GOA (2%) stocks. Genetic samples were also collected from Chinook salmon taken in the bycatch of the 2013 GOA arrowtooth flounder trawl fisheries. Those samples were collected opportunistically from a single vessel; consequently, the resulting stock composition estimates should be considered as stock compositions of the sample set rather than a representative composition of the overall bycatch. Based on the analysis of 279 Chinook salmon bycatch samples, West Coast U.S. (43%), British Columbia (39%), Coastal Southeast Alaska (14%), and Northwest GOA (3%) stocks comprised the largest stock groups. We also produced a stock composition estimate of Chinook salmon from a single test haul of the salmon excluder device performed in April 2013 in an area near Kodiak Island in Shelikof Strait. Stock composition results showed that the majority of those 95 Chinook salmon originated from West Coast U.S. (79%), British Columbia (17%), and Coastal Southeast Alaska (3%) stocks.