Posted by: salamandercandy | October 12, 2006

One Fish, Two Fish, Bred Fish, New Fish

Our lab is in the news! Some of the people who work with Ivan and me just published a paper in the journal Conservation Biology (Mike Blouin is our advisor, and the other authors do research in our lab or are affiliated with it). Their paper shows that maintaining steelhead in hatcheries for several generations reduces their fitness in the wild, such that these hatchery fish can’t be considered equivalent to wild fish. The dataset is truly impressive. For years, every fish that has passed over a dam on the Hood River has been recorded and sampled for tissue. Using DNA markers, our colleagues were able to construct a nearly complete pedigree, of “family tree,” for the entire population, and show how many descendents each fish produced. Wild fish contribute much more to subsequent generations than do hatchery stock. Essentially, the hatchery stock have been domesticated; they have evolved to survive well in a hatchery, and are losing some of their adaptations for life in the wild. However, if fish are taken into hatcheries fresh from the wild, instead of being recycled through the hatchery year after year, they still have high fitness. Thus, hatcheries can help declining fish populations but they cannot solve the problem alone. We need wild habitats where fish can thrive indefinitely. The story has been picked up by the Associated Press and can be read on Yahoo News, and our lab has made the front pages of local papers.

This is the kind of result that makes everyone happy. Environmentalists can bolster their claim that hatcheries have been harmful to fish populations, while those who favor hatcheries can point out that hatcheries are useful if we just manage them correctly. The AP has chosen the headline, “Modern hatcheries aid wild salmon,” which is an interesting choice of words. Compare that to the headline of the Oregonian yesterday, “Hatchery fish fail to thrive in the wild,” which sounds like the exact opposite conclusion. What the study has shown is that it all depends on how you run your hatchery.

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Responses

  1. Very cool!


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