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Phenotypic and genetic evaluation of Fraser strain Arctic charr (Salvelinus alpinus) in brackish and freshwater

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dc.contributor.advisor Ferguson, Moira
dc.contributor.advisor Danzmann, Roy
dc.contributor.author Chiasson, Marcia
dc.date.accessioned 2013-04-08T13:08:47Z
dc.date.available 2013-04-08T13:08:47Z
dc.date.copyright 2013-03
dc.date.created 2013-03-28
dc.date.issued 2013-04-08
dc.identifier.uri http://hdl.handle.net/10214/6313
dc.description.abstract I examined phenotypic and genetic variation in growth traits in 30 families of commercial Fraser strain Arctic charr (Salvelinus alpinus) reared in freshwater (FRW) and brackish water (BRW) in Eastern Canada. I detected family by treatment interactions for all traits [body weight (BW), condition factor (K) and specific growth rate (SGR)] across all measurement dates and growth intervals, however, mean family BW in FRW was correlated phenotypically with BRW BW. In addition, FRW fish showed significantly greater survival than those transferred to BRW and fish which survived until the conclusion of the experiment were significantly heavier in BW at the baseline assessment than their full-sibs that died. These observations suggest that BW in FRW and BW in BRW should be analyzed as separate but correlated traits in Arctic charr breeding programs. I then tested the potential for genetic improvement in this species by calculating genetic parameters for BW and K, and tested if previously identified quantitative trait loci (QTL) for these traits were detectable across the broodstock. QTL with experiment-wide and chromosome-wide significance for body size and condition factor were detected on multiple linkage groups. Heritability for BW and K was moderate in FRW (0.29-0.38) but lower in BRW (0.14-0.17). Genetic correlations for BW across environments were positive and moderate (0.33-0.67), however equivalent K correlations were weaker (0.24-0.37). This information was then used to predict the rate of genetic change following one generation of selection for BW using phenotypic selection and genomic methodologies including marker-only selection and marker assisted selection. The greatest response in the rate of genetic change was achieved by selecting only from families in which significant BW QTL had been identified. As such, marker assisted selection showed the greatest gain in genetic response with 5.4% in FRW and 4.3% in BRW. These results have applications to commercial aquaculture as the Canadian aquaculture industry is attempting to diversify with alternative species. Such genetic improvement strategies will aid in developing a strain of Arctic charr characterised by increased BW. en_US
dc.description.sponsorship Funding provided through the NSERC Strategic grants program. The project was sponsored by CanAqua Seafoods Ltd. in collaboration with the Coastal Zones Research Institute. en_US
dc.language.iso en en_US
dc.subject Arctic charr aquaculture en_US
dc.subject Gene by environment interactions en_US
dc.subject Quantitative trait loci for growth traits en_US
dc.subject Heritability en_US
dc.subject Selective breeding en_US
dc.title Phenotypic and genetic evaluation of Fraser strain Arctic charr (Salvelinus alpinus) in brackish and freshwater en_US
dc.type Thesis en_US
dc.degree.programme Integrative Biology en_US
dc.degree.name Doctor of Philosophy en_US
dc.degree.department Department of Integrative Biology en_US
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