Identification of the origins of chinook salmon captured as bycatch in fisheries targeting groundfish in the Gulf of Alaska and Bering Sea/Aleutian Islands is a management and conservation concern.  Mixed-stock analysis using genetic data has been successfully used to identify stock components of chinook salmon mixtures in Washington and British Columbia and may be an ideal tool for identifying stock of origin of bycaught chinook salmon in Alaskan waters.  Although populations of chinook salmon from California to British Columbia have been genetically characterized, data describing Alaskan populations are limited.  In this study the investigators collected genetic data from wild-spawning and hatchery populations of chinook salmon from throughout Alaska to better identify populations that may be contributing to bycatch in the Gulf of Alaska and the Bering Sea.  The investigators also developed a multiplex screen to assay genetic variation at microsatellite loci, a class of DNA markers.  With the allozyme data, the investigators performed simulation studies using maximum likelihood methods to test identifiability of regional stock groupings of chinook salmon in mixtures.  Data were included from throughout the North American range of chinook salmon.  Eight regions were studied:  (1) Western Alaska; (2) Southeast Alaska; (3) British Columbia, non-Fraser River; (4) British Columbia, Fraser River; (5) Puget Sound; (6) Washington Coastal; and (8) California-Oregon.  The results of the simulations indicate that major regional groups of chinook salmon can be identified in mixtures with a high degree of accuracy and precision.