[env-trinity] hatchery research

[Seth Naman]

Below is the abstract from a recent paper in the journal Science and also an
article in the Oregonian about the research which took place on the Hood
River.

 

Seth

 

 


Seth W. Naman

Fisheries Biologist

Yurok Tribal Fisheries Program

Office: 530-625-4130

Fax: 530-625-4148

Cell: 707-498-8236

 

 

>From the journal Science.


Science 5 October 2007:
Vol. 318. no. 5847, pp. 100 - 103
DOI: 10.1126/science.1145621


Reports


Genetic Effects of Captive Breeding Cause a Rapid, Cumulative Fitness
Decline in the Wild


Hitoshi Araki,* Becky Cooper, Michael S. Blouin 

Captive breeding is used to supplement populations of many species that are
declining in the wild. The suitability of and long-term species survival
from such programs remain largely untested, however. We measured lifetime
reproductive success of the first two generations of steelhead trout that
were reared in captivity and bred in the wild after they were released. By
reconstructing a three-generation pedigree with microsatellite markers, we
show that genetic effects of domestication reduce subsequent reproductive
capabilities by ~40% per captive-reared generation when fish are moved to
natural environments. These results suggest that even a few generations of
domestication may have negative effects on natural reproduction in the wild
and that the repeated use of captive-reared parents to supplement wild
populations should be carefully reconsidered. 

Department of Zoology, 3029 Cordley Hall, Oregon State University Corvallis,
OR 97331, USA. 

To whom correspondence should be addressed. E-mail:
<mailto:arakih at science.oregonstate.edu> arakih at science.oregonstate.edu

 

>From the Oregonian.

http://www.oregonlive.com/oregonian/stories/index.ssf?/base/news/11915565235
5280.xml
<http://www.oregonlive.com/oregonian/stories/index.ssf?/base/news/1191556523
55280.xml&coll=7&thispage=2> &coll=7&thispage=2


Hatchery fish found to be poor at survival 


Genetics - A study indicates steelhead are so bad at surviving that they are
little help to wild runs 

Friday, October 05, 2007

MICHAEL MILSTEIN 

The Oregonian Staff 

Steelhead turned out by hatcheries quickly evolve into a kind of swimming
livestock with a poor chance of surviving in the wild and may carry their
inferior traits into wild populations that biologists are trying to save, a
new study of fish in Oregon's Hood River has found. 

The Oregon State University research, published Thursday in the journal
Science, raises questions about the common practice of trying to rebuild
wild populations by adding legions of hatchery fish. The study looked only
at steelhead, but its findings may also extend to other species such as
salmon. 

"The assumption is that these fish we're adding are just as fit as the wild
ones," said Michael Blouin, the OSU professor who directed the research.
"What we see is a dramatic decline in fitness that's surprising." 

 

Other scientists found the results especially stunning because of how
quickly hatchery fish, in successive generations, lost the talents that make
wild salmon and steelhead superior survivors. Researchers measure the
reproductive fitness of fish by the number of their offspring that survive
to adulthood; for hatchery-raised fish, that declined nearly 40 percent per
generation. 

"The magnitude of the change is off the scale," said Mark Chilcote, an
Oregon Department of Fish and Wildlife biologist who was not involved in the
research. "I can understand why it would happen. I just don't understand why
it would happen so quickly." 

Sheltered environments seem to help fish survive even with traits that would
handicap them -- and their offspring -- in the wild, researchers said. The
hatchery fish then carry those handicaps with them when they're released
into rivers, where they find themselves at serious disadvantage. 

"This study just shows the power of natural selection," Blouin said.
Hatchery fish rapidly become "highly domesticated," he said. "They're like a
form of livestock. When they go out and reproduce in the wild, they don't do
very well." 

It's not clear exactly what characteristics handicap the hatchery fish, he
said. They may not survive the rough ocean as well, or they may lay their
eggs in poor locations. 

The research was possible because state biologists collect scales from fish
returning to the Hood River to spawn. The OSU scientists extracted DNA from
the scales and used it to decipher the family tree of each fish. That tells
them which ones had hatchery-raised parents, and how many survived their
rigorous life cycles, which take them from their home stream to the ocean
and back again. 

The OSU scientists previously published research looking at the first
generation of hatchery fish. But the research published Thursday carried the
study to successive generations, concluding that the more generations fish
spend in hatcheries, the worse they do in the wild. 

That doesn't matter so much if a hatchery is producing fish for people to
catch and eat. But it does matter if it's turning out fish to rebuild
struggling wild populations. 

"No evidence" 

"There's no evidence that actually works," Blouin said. "Now there's enough
evidence to make one a little worried." 

It's also possible that the large numbers of hatchery fish added to streams
outweighs their genetic drawbacks, he said. 

 

Still, the practice of adding hatchery fish to rivers may hide underlying
problems -- such as deteriorating habitat conditions -- that keep the wild
fish from recovering on their own. 

"Unless you fix the habitat, hatchery fish are just a crutch," Blouin said.
"You're just putting out lots of fish to keep the wild fish from going
extinct." 

But hatcheries do play a vital role in keeping salmon populations going in
the face of hydroelectric dams that kill many young fish and loss of
habitat, said Peter Galbreath, a fisheries scientist at the Columbia River
Intertribal Fish Commission, which represents Northwest tribes on fisheries
issues. He agrees there are drawbacks to hatchery fish, though he doubts
they're as severe as Blouin's research suggests. 

Either way, there are few other options to keep enough fish in rivers to
fulfill the treaty rights of Northwest tribes that depend on salmon, he
said. 

"Natural production has not been able to maintain populations, and the
populations have crashed," he said. "The tribes would be the first ones to
want to shut down hatcheries, (but) it is really the only option left that
can provide, in the short term, substantive increases in abundance." 

Michael Milstein: 503-294-7689; michaelmilstein@ news.oregonian.com

 

 

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