Hayes M.C., Reisenbichler R.R., Rubin S.P., Drake D.C., Stenberg K.D., Young S.F.
Western Fisheries Research Center, US Geological Survey, 6505 NE 65th Street, Seattle, WA 98115, United States; School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, WITS 2050 Johannesburg, South Africa; Washington Department of Fish and Wildlife, Molecular Genetics Laboratory, 600 Capitol Way N, Olympia, WA 98501, United States
Hayes, M.C., Western Fisheries Research Center, US Geological Survey, 6505 NE 65th Street, Seattle, WA 98115, United States; Reisenbichler, R.R., Western Fisheries Research Center, US Geological Survey, 6505 NE 65th Street, Seattle, WA 98115, United States; Rubin, S.P., Western Fisheries Research Center, US Geological Survey, 6505 NE 65th Street, Seattle, WA 98115, United States; Drake, D.C., School of Animal, Plant and Environmental Sciences, University of the Witwatersrand, Private Bag 3, WITS 2050 Johannesburg, South Africa; Stenberg, K.D., Western Fisheries Research Center, US Geological Survey, 6505 NE 65th Street, Seattle, WA 98115, United States; Young, S.F., Washington Department of Fish and Wildlife, Molecular Genetics Laboratory, 600 Capitol Way N, Olympia, WA 98501, United States
Performance of wild (W) and hatchery (H) spring Chinook salmon (Oncorhynchus tshawytscha) was evaluated for a sixth generation hatchery program. Management techniques to minimize genetic divergence from the wild stock included regular use of wild brood stock and volitional releases of juveniles. Performance of HH, WW, and HW (hatchery female spawned with wild male) crosses was compared in hatchery and stream environments. The WW juveniles emigrated from the hatchery at two to three times the rate of HH fish in the fall (HW intermediate) and 35% more HH than WW adults returned (27% more HW than WW adults). Performance in the stream did not differ statistically between HH and WW fish, but out migrants (38% WW, 30% HW, and 32% HH fish) during the first 39 days of the 16-month sampling period composed 74% of total out migrants. Differences among hatchery-reared crosses were partially due to additive genetic effects, were consistent with domestication (increased fitness for the hatchery population in the hatchery program), and suggested that selection against fall emigration from the hatchery was a possible mechanism of domestication.