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ABOUT...
ACROSS CANADA
AND...
RESOURCES
FACT SHEET - Atlantic Salmon aquaculture research
Dr. Brian Glebe and Mr. Wilfred Young-Lai at Fisheries and Oceans Canada’s (DFO) St. Andrews Biological Station are leading programs to investigate improvements in Atlantic salmon genetics and disease management for the aquaculture industry. These are collaborative research projects with industry, universities and other research institutes.
Genetics
Genetics is involved in the regulation of all production traits in farmed salmon. These traits include growth, age at maturity, flesh colour, protein and fat content, early smoltification, and disease resistance. Current research activities are intended to improve these traits by combining the traditional methods of family selection (similar to those historically used in agriculture where the best performing individuals are selected as breeders) with modern molecular techniques such as DNA fingerprinting.
Annually since 1998, 100 families (one male mated to one female) have been produced as part of an industry-supported quantitative breeding program. Individuals from the best families, identified by a selection index for economically important traits, are being bred to concentrate favourable genes in subsequent generations. The performance of individual fish is followed from the juvenile stage through to market–size using internal electronic tags. Each fish then has a unique permanent frequency signature which can be scanned when measurements are taken.
Molecular genetic technologies are being used both to maintain pedigrees and to identify gene groupings called quantitative trait loci which may be correlated with important production traits. DNA molecular markers, also known as microsatellite markers, are being used to assess the pedigrees in broodfish to eliminate inbreeding. Furthermore, the chromosomal locations of genes correlated with important economic traits (such as market size) are being studied. This information can then complement the quantitative selection program to improve strain performance for the particular traits.
DFO is a partner in this program with the salmon farming industry, Atlantic Canada Opportunities Agency, the Huntsman Marine Science Center and the University of Guelph.
Disease Management
Disease - Infectious Salmon Anemia (ISAv) in particular - is the cause of most of the economic loss to salmon farmers. Management strategies include improvement of genetic resistance to disease and vaccine development. Currently, methods of incorporating disease resistance into the genetic selection program are being investigated. In this study, families of salmon are being evaluated for their immunological response both after vaccination and after challenge with a pathogen such as ISAv. Salmon that survive ("good responders") will be incorporated into the breeding program to improve this trait in the next generation. The end result could be a generally more disease-resistant stock and one that responds better to vaccination. Also, molecular technology is being used to find genetic markers in good responders. If these markers are detected, the assessment of future families may be less time-consuming because a full immunological assessment would not be necessary. Families of good responders are being subjected to a full genome scan of molecular markers to identify the quantitative trait loci.
The salmon farming industry currently vaccinates over nine million smolts against a suite of pathogens. However, the ISAv component in these vaccines has produced variable results in terms of protection from this virus. Ongoing studies are intended to reduce or eliminate losses due to this pathogen on farms.
DFO is a partner in this program with industry, AquaNet (a university consortium) and two biotech companies, Aqua Health (Novartis, PEI) and Maine Biotek.
