Population structure of lake-type and river-type sockeye salmon in transboundary rivers of northern British Columbia

The population structure of 'lake-type' and 'river-type' sockeye salmon Oncorhynchus nerka, primarily in transboundary rivers in northern British Columbia, was examined with a survey of microsatellite variation. Variation at 14 microsatellite loci was surveyed from c. 3000 lake-type and 3200 river-type sockeye salmon from 47 populations in six river drainages in British Columbia. The mean F-ST for the 14 microsatellite loci and 47 populations was 0.068, and 0.034 over all river-type populations. River-type sockeye salmon were more genetically diverse than lake-type sockeye salmon, with expected heterozygosity of river-type sockeye salmon 0.72 and with an average 12.7 alleles observed per locus, whereas expected heterozygosity of lake-type sockeye salmon was 0.65 with and average 10.5 alleles observed per locus. River drainage of origin was a significant unit of population structure. There was clear evidence of genetic differentiation among river-type populations of sockeye salmon from different drainages over a broad geographic range in British Columbia. (C) 2004 The Fisheries Society of the British Isles.