Detection of European ancestry in escaped farmed Atlantic salmon, Salmo salar L., in the magaguadavic river and Chamcook Stream, New Brunswick, Canada

The use of European Atlantic salmon strains for commercial culture by the salmon farming industry has never been permitted in Nova Scotia or New Brunswick, Canada. Despite this, varying levels of European ancestry were detected in escaped farmed salmon in the Magaguadavic River (in 1999 and 2000) and in Chamcook Stream (in 2003), New Brunswick. Of the 53 escaped farmed salmon smolts from the Magaguadavic River and 17 escaped farmed parr from Chamcook Stream analysed, a single European “type” allele was observed at a single locus in two escaped farmed salmon smolts from the Magaguadavic River and in two escaped farmed parr from the Chamcook Stream. Of the 35 escaped farmed salmon adults analysed, two captured at the Magaguadavic fishway had European “type” microsatellite alleles at multiple loci and one also exhibited European “type” mitochondrial DNA. These results highlight the need for better containment strategies for freshwater hatcheries and genetic screening programmes for farmed salmon broodstock to minimize the likelihood of the introgression of non-local genetic material into severely depressed wild Atlantic salmon populations in the Bay of Fundy region.