Stock identification of coho salmon (Oncorhynchus kisutch) using minisatellite DNA variation

The minisatellite DNA probe Ssal was used to survey variation in 19 British Columbia, 1 Yukon, 1 Alaskan, and 1 Russian populations of coho salmon (Oncorhynchus kisutch). Hybridization of Ssal to DNA restricted with five restriction enzymes revealed 2-12 restriction fragments derived from a single locus. Geographically, although no marked regional definition was found within stocks from northern British Columbia, the lower mainland, the Fraser River, and Vancouver Island, genetic variation between individual stocks was high. Fish were correctly identified to stock of origin with an accuracy of 45% using discriminant analysis and a jackknifed classification procedure with a 22-stock baseline. Estimated mixture proportions for the contributing stock in test samples comprising a single stock averaged 100% using a fixed baseline of 22 stocks (i.e., no error), and 89% when the baselines were resampled. Further, the stock composition of simulated mixed fishery samples containing up to seven southern British Columbia stocks was estimated within an average of 1.4% of the actual mixing portions, on the basis of a resampled baseline.