[env-trinity] John Driscoll Eureka Times Standard on Klamath Fish Parasite

[Byron]

What's killing Klamath's fish? Thriving parasites may threaten salmon more
than ever 
By John Driscoll The Times-Standard 

Monday, June 21, 2004 - 

Populations of salmon-killing parasites on the Klamath River appear to be 
growing in recent years, and scientists are trying to get a grip on why the 
problem is becoming so severe. 

In the past five weeks, biologists have been sampling juvenile chinook 
salmon and finding many of them infected with one or two parasites. One hits

the fishes' digestive tract, the other their kidneys. 

While some suspect low flows and warm, poor-quality water are making the 
fish more susceptible to the parasites, scientists are just beginning to 
understand the scope of the problem. Some say the Klamath River is a system 
so out of whack that the parasites have begun to flourish in ways not common

in parasite-host relationships. 

U.S. Fish and Wildlife pathologist Scott Foott said it appears the high rate

of infection this year is a result of an exceedingly high dose of the 
parasites. 

The first parasite is Ceratomyxa shasta, which has been known to infect 
between 12 and 40 percent of juvenile salmon in recent years. The other is 
Parvicapsula minibicornis -- which has in the past been found in nearly all 
juvenile salmon. This year, some 63 percent of the little fish are thought 
to be affected so far. 

Foott could not say whether the die-off compares to the 2000 juvenile fish 
kill, when an estimated 200,000 succumbed to the diseases. 

C. shasta's intermediate host is a freshwater worm, and a similar host may 
hold P. minibicornis, though pathologists aren't sure. 

While both crop up along the length of the river, the problem appears most 
acute in the area just below the Klamath's lowermost dam, Iron Gate. 

"We're thinking that the hot spot for infection is probably in the upper 
reaches," Foott said. 

Foott said he doesn't know why. But he said some have suggested that the 
Klamath's flows are crimped by irrigation and hydropower at critical times 
of the year. Winter and spring flows may have previously scoured many of the

intermediate hosts from the river, the hypothesis goes. 

A graph of the river's historic flows -- still a disputed topic -- generated

from information by the National Marine Fisheries Service, shows a 
bell-shaped curve. After the dams were built on the Klamath, the graph shows

more water coming down in late fall and winter, only to be cut back in the 
spring when water for the federal government's upstream Klamath Irrigation 
Project is stored. 

Foott said scientists may have missed a chance to study how big winter and 
spring flows affect the abundance of the parasites in 1997 and 1998, an el 
Niño year that dumped huge amounts of rain and snow in the watershed. 

Just two years later, though, more than 200,000 infected juvenile salmon 
died in the river. 

Portland, Ore.,-based PacifiCorps' hydropower dams also alter the river's 
flow regime. The reservoirs behind the dams also act to enrich nutrients and

warm the already poor-quality river water let loose from Upper Klamath Lake.


That sparks algae blooms that turns the water alkaline and drops the amount 
of dissolved oxygen in the lakes, according to research done by the Klamath 
Basin Tribal Water Quality Work Group. 

Salmon get stressed in such conditions, making them vulnerable to diseases. 
California and Oregon water quality officials have said the conditions are 
unacceptable. 

In contrast, the disease rate in Klamath tributaries like the far-cleaner 
Salmon and Trinity rivers are markedly lower. 

PacifiCorps six dams now in the federal relicensing process, and lower river

proponents are pushing for a major investigation of the facilities' effects 
on water quality. 

'Serious problem' 

This year was declared a dry year by the Reclamation Bureau. That was a 
change from the initial "below average" forecast, which would have allowed 
more water down the river. Through a multimillion-dollar water bank, 
Reclamation is supplementing the flows this spring. 

Reclamation spokesman Jeff McCracken said there is another 10,000 acre feet 
-- 3.25 billion gallons -- available should state and federal wildlife 
agencies request it. He said the bureau hasn't heard anything from the 
agencies to date. 

The California Department of Fish and Game is still mulling over whether to 
use the water. While flows were cut back on Tuesday, and water temperatures 
are climbing, Fish and Game Fisheries Program Manager Gary Stacey said the 
relatively small amount of water might not do any good. 

"There's not a whole heck of a lot of water to go around," Stacey said. 

If water temperatures climb high enough to force the several million young 
fish in the system to crowd into the cooler mouths of tributaries, Stacey 
said, things could get worse. Temperatures above 70 degrees can cause the 
parasites to multiply rapidly, especially in crowded conditions, putting 
heat-stressed fish at even worse risk. 

Water temperatures at Klamath Glen hit 68 degrees on Friday. 

Fishermen are concerned that strung together, the 2000 fish kill, the 2002 
adult fish kill that claimed 34,000 salmon, a spring die-off this year and 
another potential adult fish kill this fall could put the brakes on 
commercial, sport and tribal harvest. 

The 2002 fish kill was caused by a protozoan infection commonly called ich 
and a bacterial infection called columnaris. Fish and Wildlife found that 
low, warm water held up migration of the fish in the lower river, leaving 
them prone to infection. 

"There's a serious problem in that basin," said Eureka commercial fisherman 
Dave Bitts. "The signs are not good." 

He said Reclamation is ignoring a key element: That its operations are set 
up to prevent harm to threatened coho salmon, not chinook, which spend more 
time in the main channel of the river. 

The National Research Council, in its report on the Klamath, held the same 
view. 

As biologists try to piece together the disease complex, they are also faced

with the reality of inconsistent funding. Foott said scientists need to 
figure out why C. shasta, for example, isn't found in Klamath tributaries 
even though its spores are released after spawning fish die. 

"It's not a well-funded effort at all," he said. 

Reclamation may be beginning to feel the importance of the issue.  

McCracken said the bureau is exploring the possibility of further funding 
state, federal and tribal efforts to monitor the problem. 

 

 

Byron Leydecker

Chair, Friends of Trinity River

Consultant, California Trout, Inc.

PO Box 2327

Mill Valley, CA 94942-2327

415 383 4810 ph

415 519 4810 ce

415 383 9562 fx

bwl3 at comcast.net

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

http://www.fotr.org

 

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