[env-trinity] Eureka Times-Standard - 2/1/07

[Byron Leydecker]

Klamath salmon still ailing

Eureka Times-Standard - 2/1/07

By John Driscoll, staff writer

 

FORTUNA -- A large portion of salmon in the Klamath River continue to become
infected by pathogens and die each year, especially when the water is warm
and they crowd into cool spots for relief. 

 

Biologists gathered on Wednesday to give a prognosis on the health of the
river's fish, and there was not much positive information. Scientists are
trying to understand the complicated relationship between conditions in the
river, a worm-like host that harbors two key pathogens and how fish handle
infection and disease. 

 

Studies show that the polychaete worm that is an intermediate host to the
pathogens is most heavily infected below Iron Gate Dam, the lowest on the
river. It's also prevalent far above all of the dams, in the Williamson
River. 

 

High numbers of parasite spores are released when adult spawning salmon die,
and the most spawners are seen just below Iron Gate Dam, said Jerry
Bartholomew, a researcher for Oregon State University. 

 

The annual conference has drawn more people as attention on the Klamath has
intensified. Commercial fishing was shut down last year and sport and tribal
fishing slashed to protect a weak run of fish, causing tens of millions in
economic losses along a long stretch of the West Coast. 

 

As water temperature in the river increases, one parasite begins to
replicate quickly, and fish infected by it die more rapidly. The incidence
of infection in young salmon jumped quickly on May 1, 2006, one month later
that a similar spike on April 1, 2005, according to a presentation by Ken
Nichols with the U.S. Fish and Wildlife Service. 

 

Nichols said it almost looks as if there were a trigger responsible for the
sharp jump in infection at those times, but it had not yet been identified. 

 

Scott Foott, a pathologist with the U.S. Fish and Wildlife Service said that
the Klamath's native fish have evolved with the pathogens, but get
overwhelmed when conditions are stressful. They crowd together in cool spots
when water gets warm and that allows infection to spread rapidly, he said. 

 

"It's kind of a death of a thousand cuts," Foott said. 

 

Fisheries biologist Pat Higgins asked if high pH and ammonia levels observed
below Iron Gate Dam would suppress the immune response of salmon. Foott said
any additional stress would probably make the fish more susceptible. 

 

Rebecca Quinones with the U.S. Forest Service reported that hatchery bred
fish are more and more often spawning in the river -- making up 13 percent
of the chinook salmon that return to the Klamath. That percentage is as high
as 40 percent in the Shasta River. 

 

Quinones also said that 2006 was another bleak year for spring run salmon,
which almost exclusively return to a single tributary of the Klamath -- the
Salmon River -- not including the Trinity River. The number of adult
steelhead that return to Iron Gate Hatchery is also decreasing, she said.

 

 

Byron Leydecker

Friends of Trinity River, Chair

California Trout,Inc., Advisor

PO Box 2327

Mill Valley, CA 94942-2327

415 383 4810 ph

415 383 9562 fx

 <mailto:bwl3 at comcast.net> bwl3 at comcast.net

 <mailto:bleydecker at stanfordalumni.org> bleydecker at stanfordalumni.org
(secondary)

http:// <http://www.fotr.org> www.fotr.org

http:// <http://www.caltrout.org> www.caltrout.org 

 

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