Cooperative Fish and Wildlife Research Units Program: Idaho
Education, Research and Technical Assistance for Managing Our Natural Resources

Fish that exhibit high foraging activity or bold behavior can be particularly vulnerable to angling. If these traits are heritable, harvest by angling can select on them, eventually rendering a target population less vulnerable to angling and consequently impacting the quality of the fishery. In this study, we used parental-based tags to investigate whether vulnerability to angling might be heritable in steelhead trout (Oncorhynchus mykiss) spawned at a hatchery in western Oregon, U.S.A. We found no evidence to support the hypothesis that vulnerability to angling is a heritable trait in steelhead. In fact, steelhead whose parents had been collected by anglers were less likely to be caught by anglers than expected. Moreover, we found that steelhead collected with in-river traps produced nearly twice as many adult offspring as steelhead collected by anglers. The underlying mechanisms for this difference in adult-to-adult production remain to be identified, though effects from collection stress and time in captivity prior to spawning offer candidate explanations. Our findings suggest that hatcheries could optimize the fitness of fish they spawn by using traps to collect broodstock, in favor of angler-assisted collection programs. We suggest that future research investigate the mechanisms contributing to fitness differences between broodstock fish collected with traps and by anglers.