Hatchery Fish Quick to Hurt Reproduction in Wild

By TRT Staff

Oregon State University scientists found that it takes only a single generation for steelhead trout raised in fish hatcheries to pass along bad genetic traits to populations in the wild. The findings are the latest in a growing body of evidence showing the downside to hatcheries as a way to rebuild threatened and endangered salmon and steelhead runs. Studies of Hood River steelhead had previously pinpointed declining reproduction success by hatchery fish in the wild, but the latest research shows it is a result of domestication of young fish in hatcheries that can be transmitted in breeding with wild fish, not from a temporary environmental effect.

The findings, published in the Proceedings of the National Academy of Sciences, raise concern about programs to supplement wild populations of salmon and steelhead by releasing young hatchery fish near spawning grounds. Unlike conventional hatcheries, supplementation programs try to integrate the hatchery populations into wild populations, many protected under the Endangered Species Act. Supporters of the hatchery supplementation programs caution against concluding that supplementation is bad. Tribes use it to help fulfill government promises to sustain tribal fisheries after Columbia Basin dams were built and in treaties signed in the mid-1800s. The tribes say they can manage hatcheries to reduce domestication problems and have advocated doing so for two decades. Recent studies with Snake River fall Chinook indicate carefully run programs can boost numbers of wild fish. An OSU professor who participated in the study says it should lead scientists to focus on what’s going wrong in hatcheries. If crowded tanks prove to be a key problem for example, hatcheries could reduce fish numbers or build more tanks.

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