As many fly fisherman and conservationists have suspected, hatchery programs have had an adverse effect on the numbers of wild anadromous fish. They compete for forage, spawning areas, and travel in large pods, making steelhead descending their natal streams, easy targets for predators awaiting them at the mouth of the estuary.
New findings are concluding that when hatchery fish do mate with wild fish, their offspring contain traits that are “beneficial to them in captivity, but are severely maladaptive in the wild.”
Story by Scott Learn, The Oregonian
Genetic adaptation of hatchery steelhead starts hurting spawning success within just one generation, according to a study of Hood River fish that could lead to pinning down the causes of hatchery domestication.
Classic Darwinian evolution is clearly at work –and it’s working fast, the researchers concluded in their study, published today by the Proceedings of the National Academy of Sciences.
“Now we know definitely that it’s adaptation to captivity and it happens in a single generation, which is amazing from an evolutionary standpoint,” Mark Christie said, an Oregon State University genetic researcher and the study’s lead author.
To read the full article, click the link below: http://www.oregonlive.com/environment/index.ssf/2011/12/study_of_hood_river_steelhead.html