Hatchery Steelhead Far Less Productive Spawners Than Wild Steelhead
By Tom Chandler on Oct 9, 2007 in Environment, News
Here’s a shocker; hatcheries might keep the numbers of fish up, but they do little to recover endangered species.
In fact, steelhead grown in hatcheries quickly lose their ability to spawn in the wild, and this despite the $90 million spent annually on hatcheries in the Puget Sound and Columbia basin alone.
Another chilling statistic? 95% of the salmon and steelhead returning to the Columbia Basin are hatchery fish. Which — it turns out — don’t spawn very well.
GRANTS PASS, Ore. (AP) Steelhead trout grown in hatcheries lose their ability to produce offspring in the wild, raising concerns about whether captive breeding programs can help save endangered fish, a new study concludes. Scientists at Oregon State University found that even when hatcheries breed fish captured in the wild, their offspring become less and less successful at reproducing in the wild than their cousins that never left the river.
“The argument that hatchery fish and wild fish are functionally equivalent is basically dead,” said Michael Blouin, a population geneticist and associate professor of zoology at Oregon State University.
[UPDATE: This quote from a Nature News story adds detail, and the story itself offers more detail than the cited AP source.]
“What’s starkly clear,” says Blouin, “is that using hatchery fish to produce another generation of hatchery fish causes a very rapid decline in fitness.” Simply raising fish in captivity cuts their reproductive success by 15%. As the researchers report in this week’s Science 1, having one captive parent in addition to being raised in captivity will reduce reproductive success by an additional 45%, thanks to genetic effects.
Of course, we’ll see the usual battery of “biased study” charges from those with an economic interest in counting hatchery fish, so let’s get right to the methodology:
The study is based on 15 years of genetic samples collected from every steelhead, wild and hatchery, that passes over a dam on the Hood River, which flows off Mount Hood in Oregon into the Columbia River.
Stay tuned while the Steelhead & Salmon Wars continue — right here on the Trout Underground (Home of the “Goddamned Fin Huggers”).
See you on the river, Tom Chandler.
Technorati Tags: fly fishing, steelhead, salmon, hatchery steelhead
KW Morrow | Oct 10, 2007 | Reply
I have always questioned the effectiveness of hatchery replenishment of wild species. It doesn’t work with birds, either. So I figured it wouldn’t work well with fish.
But this is really just another reminder to us that once it’s gone, IT’S GONE.
But I also don’t want to toss the baby with the bathwater. Hatchery fish…like reared and released pheasants…provide sporting opportunities that would otherwise no longer exist. I’m all for that. Also, I am a firm believer in our ability to EVENTUALLY figure it out…maybe. So I want the experiments and research to continue. I don’t think we should give up on hatchery fish that spawn in the wild. We simply need to realize that we still aren’t there.