AFSC/ABL: 2009 Chum Salmon Bycatch Sample Analysis Bering Sea

A genetic analysis of samples from the chum salmon (Oncorhynchus keta) bycatch of the 2009 Bering Sea walleye pollock (Theragra chalcogramma) trawl fishery was undertaken to determine the overall stock composition of the sample set. Samples were genotyped for eleven microsatellite markers and results were estimated using the current chum salmon microsatellite baseline. In 2009, genetic samples were collected opportunistically as part of a special project, but sample biases have the potential to affect stock composition analysis results. Consequently, stock composition estimates apply to the sample set and may not represent the entire chum salmon bycatch. Based on the analysis of 1,437 chum salmon bycatch samples collected throughout the 2009 Bering Sea trawl fishery, North Asian (30%), East Asian (34%), and Eastern Gulf of Alaska/Pacific Northwest (18%) stocks dominated the sample set, with smaller contributions from Western Alaska (13%), Upper/Middle Yukon River (2%), and Southwest Alaska (4%) stocks. The estimates for the 2009 chum salmon bycatch sample set were similar to the 2005 chum salmon bycatch estimates.