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Observatory: Downside To Breeding Fish In Captivity Shows Up EarlyFish hatcheries in the Pacific Northwest produce upward of five billion juvenile salmon, steelhead trout and other fish each year, introducing them to the wild. While the goal of most of these captive breeding efforts is to produce fish for harvesting, in recent years more programs have been developed with the idea of helping restore dwindling fish populations. Hitosh ArakiRelated Observatory: Pollination Starts Sweet Then Turns Sour as Day Heats Up (October 9, 2007) Observatory: A Birds-Thigh View of Tool-Making Sheds Light on Crows (October 9, 2007) More Observatory Columns » Web LinksGenetic Effects of Captive Breeding Cause a Rapid, Cumulative Fitness Decline in the Wild (Science) Over many generations, fish bred in captivity are not as fit genetically as wild fish and have less reproductive success (fewer offspring survive to adulthood). But a study by Hitoshi Araki, Becky Cooper and Michael S. Blouin of Oregon State University shows that the negative effects of captive breeding begin to show up even in the first few generations. The researchers compared three groups of steelheads: fish born of two wild parents and reared in the wild; first-generation captive fish (born of two wild parents and reared in captivity); and second-generation captive fish (with one captive-bred parent). They report in Science that the reproductive success of the first-generation captive fish was about 40 percent less than that of the wild-reared fish, and that of the second-generation captive fish was another 40 percent lower. The researchers say that they dont know the precise cause of the declines, but that the findings should make conservationists reconsider if captive-breeding is the answer to restoring populations. Tag CloudExternal InformationAdditional InformationEssay: Putting Pay on the Line to Improve Health Care...Restoring a Mud-Brick Tribute to a Departed Egyptian King... Wizardry at Harvard: Physicists Move Light... Shuttle Docks With Space Station... Where Am I?News Main Page - Business - Observatory: Downside To Breeding Fish In Captivity Shows Up Early |
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