Genetic variation in mortality of chinook salmon during a bloom of the marine alga Heterosigma akashiwo |
| |
| Authors: | J. J. Hard L. Connell W. K. Hershberger L. W. Harrell |
| |
| Affiliation: | National Marine Fisheries Service, Northwest Fisheries Science Center, Conservation Biology Division, 2725 Montlake Blvd E., Seattle, Washington 98112, U.S.A.;National Marine Fisheries Service, Northwest Fisheries Science Center, Environmental Conservation Division, 2725 Montlake Blvd E., Seattle, Washington 98112, U.S.A.;University of Washington, School of Fisheries WH-10, Seattle, Washington 98195, U.S.A.;National Marine Fisheries Service, Manchester Marine Experimental Station, Resource Enhancement and Utilization Technologies Division, P.O. Box 130, Manchester, Washington 98353, U.S.A. |
| |
| Abstract: | Mortality in a netpen-reared population of 3-year-old chinook salmon Oncorhynchus tshawytscha during an extensive 1997 bloom of the alga Heterosigma akashiwo in Puget Sound, Washington, was low (7·2%), and corresponded to a reduction in variance effective population size of 9·4%. Under a liability threshold model, the heritability of mortality (± S.E.), based on paternal half-sibs, was estimated at 0·15 ± 0·04. No significant genetic variation was detected for date of death. Despite the low overall mortality, the consequences for variation in family size underscore the importance of maximizing genetic variation in cultured fish populations later released to the wild as a precaution against mortality and losses of genetic variation over the life cycle. The pattern of family variation in response to this algal bloom provides evidence for potentially selective mortality of anadromous salmonids in the marine environment during natural perturbations. |
| |
| Keywords: | heritability effective size natural selection HAB |
|
|
