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Quantifying levels of introgression of escaped farmed and wild Atlantic salmon, and exploring the genetic changes to their life history



The number of farmed Atlantic salmon now exceeds the population of wild Atlantic salmon in Newfoundland and Labrador. Farmed salmon escapes can interbreed with wild salmon altering wild population genetics and eroding local adaptations. In southern Newfoundland, first-generation hybrids (i.e., F1) were detected after farm escape events in 2013 and 2015. Survival of hybrids in freshwater is limited but the number of backcross wild individuals supports the hypothesis that a proportion of these F1 males are maturing precocially (i.e., early) and successfully reproducing. Introgression between wild and domestic salmon is likely occurring along with the potential for changes to the wild salmon life history traits (e.g., age at maturity). The ultimate impact of introgression between wild and domestic Atlantic Salmon remains difficult to resolve or predict. The overall goal of PARR-2019-NL-01 is to provide scientific advice regarding the genetic impacts of introgression between escaped farmed and wild Atlantic salmon on wild salmon populations. This research will (1) test the applicability of predictive models from Iceland for the distribution of genetic impacts in Newfoundland; (2) quantify levels of hybridization (i.e., F1 hybrids) and introgression (i.e., F2, and backcrosses) following the farm escape events in 2013, 2015, 2018 in southern Newfoundland; and (3) explore long-term impacts for life history variation using genomic analysis of age at maturity in North American Atlantic salmon.

Program Name

Program for Aquaculture Regulatory Research (PARR)



Principal investigator

Ian Bradbury
Research scientist, Northwest Atlantic Fisheries Centre, St. John’s, N.L.

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