Genetic Stock Identification of Fall Chum Salmon in Commercial Harvests, Yukon River

This project is designed to test the feasibility of analyzing stock composition of the commercial harvest at the mouth of the Yukon River drainage. Currently genetic sampling at Pilot Station sonar occurs after the District Y-1 fishery, three days into the run. Inseason genetic analyses take an additional three days, which means stock composition estimates are available a minimum of six days after the fish have passed through the sample location. Additionally it is important to determine if the commercial fishery harvests are similar in stock composition as those produced at Pilot Station sonar project. Managers must allow a target number of Canadian-origin chum salmon to pass the international border due to a bilateral international agreement to meet management objectives. Canadian-origin chum salmon contributions range from 2% to 46% throughout the run that consists of four to six pulses annually. Knowing the stock composition in the commercial harvest would result in more informed management decisions concerning Canadian-origin chum salmon. If there is no difference between stock compositions in the lower river fisheries and Pilot Station, then effort could be put into more timely analysis in either sampling location. As the majority of the commercial fishery occurs in the lower commercial districts, collecting and analyzing samples earlier in the run would improve inseason management. This project will analyze fall chum salmon genetic samples from District Y-1 commercial fishing periods during the transition from summer to fall chum salmon in mid-July when a mix of the two are being harvested. In addition, samples will be collected from the largest two pulses in the remainder of the run when the largest commercial harvests may occur. Stock compositions will be estimated using the available chum salmon baseline of single nucleotide polymorphisms (SNPs). This is a feasibility study. All samples will be analyzed post-season and the inseason utility of these analyses will be evaluated.