[env-trinity] Oregonian: Hatchery fish quick to hurt reproduction in wild

[Tom Stokely]

Hatchery fish quick to hurt reproduction in wild
 
Dec. 20, 2011, 6:30 p.m. PST
The Oregonian
 
http://www.oregonlive.com/newsflash/index.ssf/story/hatchery-fish-quick-to-hurt-reproduction-in/5dba5bd56a264104a89a1c17e9e9388d
 
PORTLAND, Ore. (AP) — Oregon State University scientists have 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, said Mark Christie, a genetic researcher and the study's lead author.

"Now we know definitely that it's adaptation to captivity and it happens in a single generation, which is amazing from an evolutionary standpoint," Christie told The Oregonian newspaper (http://bit.ly/uaaPYf).

The findings, published Monday 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, the paper reported. Unlike conventional hatcheries, supplementation programs try to integrate the hatchery populations into wild populations, many protected under the Endangered Species Act.

Supporters of 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 productivity declines in Hood River steelhead are among the sharpest of many salmon and steelhead runs studied. And damage from dams and habitat destruction likely have bigger effects on productivity and returns, hatchery supporters say.

"It's important to remember that hatchery supplementation is a response to declining or depressed salmon populations, not the cause," said Peter Galbreath, a fishery scientist with the Columbia River Inter-Tribal Fish Commission.

Supplementation is necessary "to rebuild populations at desired levels while we await, probably naively, rectification of the source problems," he said.

The tribes say they can manage hatcheries to reduce domestication problems, and have advocated doing so for two decades. Recent successes with Snake River fall chinook indicate carefully run programs can boost numbers of wild fish, they say.

Oregon State Professor Michael Blouin, who participated in the study, said 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, he said.

"In my opinion, the question of whether genetic change occurs in hatcheries has been answered," Blouin said. "If we could quit arguing about that and find out why, then we're all on the same team again."

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Information from: The Oregonian, http://www.oregonlive.com
 

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