Genetic control over survival in Pacific salmon (Oncorhynchus spp.): experimental evidence between and within populations of New Zealand chinook salmon (O. tshawytscha)

Martin J. Unwin, Michael T. Kinnison, Nelson C. Boustead, and Thomas P. Quinn
Can. J. Fish. Aquat. Sci./J. Can. Sci. Halieut. Aquat. 60(1): 1-11 (2003)

Abstract: The ability to survive to adulthood and return to natal sites is a fundamental characteristic of anadromous salmonids, and low survival is likely to have prevented establishment of new populations within and outside their native range. We hypothesised that there is family-level genetic variation in traits contributing to survival and that populations evolve to maximise survival in response to prevailing local conditions. To test these predictions, we compared postrelease survival for chinook salmon families from two populations established in New Zealand in the 1900s. Both populations, Glenariffe Stream and Hakataramea River, had similar survival when released after translocation to a drainage familiar to neither population. However, Glenariffe families had higher survival than Hakataramea families when both populations were released from Glenariffe Stream, indicating a survival advantage for the local fish. In addition, there were significant correlations between survival rates for paternal half-sib families of Glenariffe fish and between survival rates for families released from the two locations. Family-specific survival was positively correlated with weight at release, but there were underlying genetic correlations unexplained by size. Taken together, these results suggest considerable genetic influence over survival and return of salmon and that population-specific adaptation can occur within 30 generations of establishment.