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Infested fish may bear scars of global warming

Alaska salmon has been a rare success story among exploited fisheries. A species crash could be disaster.

June 15, 2008|Kenneth R. Weiss | Times Staff Writer

TANANA, ALASKA — With a sickening thud, another hefty and handsome salmon lands in the waste barrel, headed for the dogs.

"See, it's all of the biggest, best-looking fish," said Pat Moore, waving a stogie at the pile of discards. "It breaks my heart. My dogs cannot eat all that. The maggots will get them first."

More Alaskan salmon caught here end up in the dog pot these days, their orange-pink flesh fouled by disease that scientists have correlated with warmer water in the Yukon River.

The sorting of winners and losers at Moore's riverbank fish camp illustrates what scientists have been predicting will accompany global warming: Cold-temperature barriers are giving way, allowing parasites, bacteria and other disease-spreading organisms to move toward higher latitudes.

"Climate change isn't going to increase infectious diseases but change the disease landscape," said marine ecologist Kevin D. Lafferty, who studies parasites for the U.S. Geological Survey. "And some of these surprises are not going to be pretty."

The emergence of disease in Alaska's most prized salmon has come as a shock to fishermen and fisheries managers. Alaskan wild salmon has been an uncommon success story among over-exploited fisheries, with healthy runs and robust catches that fetch ever higher prices at fish markets and high-end restaurants in Los Angeles, New York, Tokyo and London.

Fishermen and regulators who have cooperated to save species from overfishing and local environmental hazards have been caught unprepared to deal with forces beyond their control: how to manage a fishery for climate change.

The return of the king -- or chinook -- salmon is eagerly anticipated along the Yukon. The biggest of the salmon species, these kings arrive with a muscular flash of the tail, sun glinting off a speckled palette of blues and greens fading to silver and red.

Savvy buyers from Japan converge on the docks near the river's mouth to purchase these fish that have bulked up with extra fat to swim more than 2,000 miles, across Alaska, to spawn in the stream of their birth.

As a fierce defender of the fish's reputation, Gene Sandone, a regional supervisor for Alaska's Fish and Game Department, was less than receptive to complaints from Tanana fishermen such as Moore that something was wrong.

The chinook salmon they pulled from the Yukon River about 700 miles inland didn't smell right. It wasn't an instant, gag-inducing stench. It was more subtle but grew into an unpleasant odor of fruit rotting in the hot sun.

More important, the flesh turned mealy. The salmon didn't dry right in smokehouses either. Instead of turning into rich red strips of salmon jerky, they turned black and oily like strips of greasy rotten mango.

"If you don't weed out the bad ones, it'll stink up the whole smokehouse," Moore said, wielding a knife on his cutting table. "I only want the good stuff. I don't want second-rate fish."

Salmon jerky strips are a staple among the Native Americans and subsistence fishermen in rural outposts such as Tanana, a village of 270 people. "It'll keep you warm in the winter," said Lorene Moore, Pat's wife and a native of the village. In Alaska's bigger cities, these strips are a prized delicacy, fetching $20 or more a pound.

When Bill Fliris, another Tanana fisherman, first noticed the problem in the late 1980s, he bundled up some salmon jerky strips and shipped them to a state Fish and Game biologist. A few weeks later, the biologist said it was "the damnedest thing -- they disappeared out of the freezer. You know: free strips."

The next year, Fliris shipped more samples, and this time they were tested. But the state Fish and Game lab found nothing amiss.

A friendly federal biologist advised the local fishermen to send samples, including hearts and organs that were covered with tiny pimples, to the Center for Fish Disease Research at Oregon State University.

The Oregon lab quickly identified it as "white spot disease," caused by a microscopic parasite called Ichthyophonus hoferi. Ich (pronounced "ick") is a well-known disease, harmless to humans, that was blamed for devastating losses in the herring fishery in Scandinavia. A similar parasite can infect aquarium fish.

The portion of Yukon salmon with Ich grew each year. Fishermen were throwing away as much as 30% of their catch, forcing them to catch more fish to fill their cache for the winter.

"The Alaskan Department of Fish and Game wasn't interested," Fliris said. "They said, 'There's no money to study this. It's a natural disease. There's nothing we can do about it.' "

So Fliris contacted an outsider: Richard M. Kocan, a fish disease expert at the University of Washington. Lining up a federal grant, Kocan began to test the fish in 2000, the same year the king salmon run suffered an unexpected temporary collapse that forced the closure of the river's commercial fishery.

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