| ECOLOGICAL IMPLICATIONS OF INTROGRESSION OF SALMONID DOMESTIC GENOTYPES INTO A NON-SELECTED GENETIC BACKGROUND |
| TYMCHUK, W. (1), and Devlin, R.H. (2), University of British Columbia / Fisheries & Oceans Canada, 4160 Marine Drive, West Vancouver, BC V7V 1N6 (604) 666-4802 tymchukw@pac.dfo-mpo.gc.ca, (2) Fisheries & Oceans Canada, 4160 Marine Drive, West Vancouver, BC V7V 1N6. |
| Domestication in fish often involves direct selection for improved growth rates as well as other correlated traits, and can therefore have a significant impact on life history. Many fitness-related traits, such as growth, competitive ability and anti-predator behaviour, have been found to have a genetic component. Selective breeding for enhanced-growth typically selects the largest mature individuals to breed for the future generation, and is in most cases being applied with little knowledge of the underlying genetic and physiological mechanisms that are being selected for. Due to an altered selection regime, the cultured fish may not be as adapted to the natural environment as wild fish. This research summarizes the growth, behaviour and physiology of fast-growing (domestic), slow-growing (non-selected), and hybrid (F1, F2, and F3) strains of coho salmon (Oncorhynchus kisutch) and rainbow trout (O. mykiss). Growth of the strains was compared under both culture and semi-natural rearing conditions. Under all environments, there was a strong correlation between growth and the proportion of domestic genes within the genotype. Comparisons of anti-predator behaviour and hormone profiles illustrated similar trends. Assessment of the expression of fitness-related phenotypes in the hybrid strains can provide information on the genetic changes that have evolved during the domestication process. Knowledge of the genetic changes responsible for altered growth rates in fish is crucial information needed to increase our ability to predict the consequences of introgression between fast and slow-growing strains of fish. |
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