Straying of hatchery salmon in Prince William Sound, Alaska

Richard E. Brenner, Steve D. Moffitt, William S. Grant
2012 Environmental Biology of Fishes  
The straying of hatchery salmon may harm wild salmon populations through a variety of ecological and genetic mechanisms. Surveys of pink (Oncorhynchus gorbuscha), chum (O. keta) and sockeye (O. nerka) salmon in wild salmon spawning locations in Prince William Sound (PWS), Alaska since 1997 show a wide range of hatchery straying. The analysis of thermally marked otoliths collected from carcasses indicate that 0-98% of pink salmon, 0-63% of chum salmon and 0-93% of sockeye salmon in spawning
more » ... are hatchery fish, producing an unknown number of hatcherywild hybrids. Most spawning locations sampled (77%) had hatchery pink salmon from three or more hatcheries, and 51% had annual escapements consisting of more than 10% hatchery pink salmon during at least one of the years surveyed. An exponential decay model of the percentage of hatchery pink salmon strays with distance from hatcheries indicated that streams throughout PWS contain more than 10% hatchery pink salmon. The prevalence of hatchery pink salmon strays in streams increased throughout the spawning season, while the prevalence of hatchery chum salmon decreased. The level of hatchery salmon strays in many areas of PWS are beyond all proposed thresholds (2-10%), which confounds wild salmon escapement goals and may harm the productivity, genetic diversity and fitness of wild salmon in this region Keywords Hatchery salmon . Straying . Hatcherywild interactions . Prince William Sound . Alaska Environ Biol Fish (2012) 94:179-195
doi:10.1007/s10641-012-9975-7 fatcat:wkr3ht3fmrg6th5a35eiikkyha