Genetic variability and components of fitness in hatchery strains of rainbow trout |
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| Authors: | R G Danzmann M M Ferguson † F W Allendorf ‡ |
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| Institution: | The Great Lakes Institute, University of Windsor, Windsor, Ontario, Canada N9B 3P4;Department of Zoology, University ofGuelph, Guelph, Ontario, Canada NIG 2W1;Division of Life Sciences, University of Montana, Missoula, Montana 59812, U.S.A. |
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| Abstract: | Two fitness components, development rate and egg size, were examined in six hatchery strains of rainbow trout, Oncorhynchus mykiss (syn. Salmo gairdneri Richardson), with different amounts of enzyme heterozygosity. The average expected heterozygosities per strain ranged from 4 to 8%, based upon an electrophoretic analysis of the protein products of 42 loci. Strains with higher heterozygosities had faster development rates, as measured by hatching time, than strains with lower heterozygosity. Concordance between hatching time and another measure of development rate, degree of yolk-sac resorption, suggests that hatching time is a valid measure of embryonic development rate in salmonid fishes. Earlier-hatching embryos were longer and heavier at the time of yolk-sac resorption than later-hatching fish. Females from more-heterozygous strains also had a tendency to have larger eggs. These data suggest that genetic variation is an important biological resource to be conserved in hatchery stocks. |
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| Keywords: | Oncorhynchus mykiss development rate egg size enzyme heterozygosity hatchery strains |
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