Genetics of Atlantic salmon and other finfish species

Participants: Manon Cassista-Da Ros (Molecular biologist), Carolyn Harvie (Assessment biostatistician), Louise de Mestral Bezanson (Biological Technician) and Patrick O'Reilly (Research Scientist)

Molecular genetic, parentage, kinship and population analyses in support of conservation and management of Atlantic salmon and other finfish species.

Genetic variation and fitness in Atlantic Salmon

Wild anadromous Atlantic salmon (Salmo salar) populations are rapidly declining throughout the southern half of the species freshwater distribution. Our group is involved in analyses directed at minimizing the loss of both genetic variation and fitness in small semi-captive populations in Nova Scotia and New Brunswick. Using pedigree information obtained through molecular genetic data and subsequent kinship and parentage analyses, we are attempting to maximize retention of founder genetic variation, and to minimize loss of genetic variation in subsequent generations due to genetic drift. In collaboration with researchers from several universities, we are also investigating the efficacy of these programs in minimizing adaptation to captive conditions and loss of fitness in the wild. Information on rates of loss of genetic variation, and changes in behaviour, morphology, and survival associated with specific management practices, will be used to adapt existing strategies, with the ultimate goal of maintaining salmon that can successfully survive and reproduce in native river habitat and that retain sufficient genetic variation to enable populations to adapt to future environmental challenges.

Population and genetic structure

Resolution of genetic structuring in fishes can be useful both in the identification of fish stocks, groups of individuals demographically independent of other such groups, and in delineating important components of a species' biodiversity for broader conservation purposes. Our group is engaged in analyses of microsatellite, SNP (Single Nucleotide Polymorphism), and MHC (Major Histocompatiblity Complex) variation in anadromous and marine finfish species, for these purposes. Our primary focus is on Atlantic salmon, were we have accumulated genotypic data on over 18,000 individuals from over 40 populations in the Maritimes, but we are also carrying out research on Atlantic cod (Gadus morhua).

Investigations into interactions between wild
and aquaculture salmon in North America

The Bay of Fundy/Gulf of Maine is home to some of the most intensive culturing of Atlantic salmon on the east coast of North America, but also to many numerically depressed and endangered wild populations. Our group is also interested in whether aquaculture escapes have impacted depressed wild populations either directly through introgression, or indirectly via the introduction and transmission of pathogens. One of our projects involves analyses of MHC variation in wild populations prior to and after the introduction of aquaculture to the region, and in populations near and distant to Passamoquoddy/Cobscook Bay, areas of high concentrations salmon farming.