Stock identification of chinook salmon (Oncorhynchus tshawytscha) using minisatellite DNA variation

Geographic variation in minisatellite DNA was examined in 28 stocks of chinook salmon (Oncorhynchus tshawytscha) from British Columbia and 3 stocks from the Yukon Territory. Genomic DNA was restricted with the enzymes RsaI and HinfI and hybridized with three minisatellite probes. Regional differentiation in allele frequencies and DNA fragment (band) counts was observed, with stocks from the Fraser River, east coast of Vancouver Island, west coast of Vancouver Island, southern mainland, and northern British Columbia forming distinct groups. With allele frequencies or band counts in the baseline stocks considered fixed or exact, estimates of stock composition from simulated mixtures within the Fraser and Skeena River drainages were accurate and precise, suggesting that discrimination among stocks within river drainages may be possible. Individual chinook salmon were classified with an average accuracy of 35% to stock in a 30-stock baseline and an average accuracy of 65% to region for eight regions. Minisatellite DNA variation offers the potential to accurately and precisely estimate chinook salmon stock composition on a fine geographic scale.