Ailment Detected In Nw Waterways

A fish infected with whirling disease was found in the Idaho Panhandle even before the parasite was confirmed in Montana.

The same scientist who later diagnosed the outbreak among the Madison River’s famous rainbows came across an infected brook trout in Big Creek last summer.

At the time, Beth MacConnell was studying mining-related metals contamination in the creek, which flows into the South Fork of the Coeur d’Alene River near Kellogg.

There hasn’t been a stir about the discovery because there’s no sign the disease is killing fish in the Idaho Panhandle.

But it’s one more cause for jitters among people who fear whirling disease - once confined to hatcheries - is continuing to spread in the wild. The disease has already infected salmon and steelhead populations, and may be one factor in their decline.

Concern, not panic, is in order, according to Trout Unlimited spokesman Peter Rafle.

“The initial panic that people had when they heard about the Madison appears to be an overreaction,” Rafle said. “On the other hand, there are some very real problems.”

Because the disease is spread via a worm that lives in the mud, it’s one more reason that fishermen should wash their boots and boats frequently.

“Anglers should take those precautions everywhere,” said MacConnell, a pathologist works for the U.S. Fish and Wildlife Service Fish Technology Center in Bozeman.

There’s much disagreement about the seriousness of the threat from whirling disease.

Scientists don’t know why it harms some trout populations, but not others. Or why it exists in some rivers without hurting fish.

Fishing pressure, climate, or competition from other species might stress out a fish population and make it more susceptible, MacConnell said.

“This parasite is way down on our list” of diseases to worry about, said Steve Roberts, the Spokane-based pathologist for the Washington Department of Fish and Wildlife. But within six months, his agency plans to check some southeastern Washington rivers, such as the Spokane and Tucannon. Whirling disease was found nearby in Oregon’s Grande Ronde and Imnaha rivers in the late ‘80s, Roberts said.

“Potentially, it could be in the Spokane River,” he said, noting that Big Creek is upstream from there.

Idaho is checking fish from every river drainage for the disease.

“When we find out where it is, we want to look at the populations and see if it’s a problem,” said state fish pathologist Kent Hauck.

Samples taken from the Coeur d’Alene River this year didn’t turn up whirling disease. But it’s been found in both wild and hatchery salmon in the Salmon River drainage.

“Some researchers think it’s affecting steelhead,” Hauck said. “As these guys are out snorkeling, they see signs of it in wild fish. Also, the runs are declining … it may be a factor.”

When the parasite was found at the Hayspur hatchery in southern Idaho, the state Fish and Game Department stopped raising fish there for its stocking program.

Whirling disease was also found at the Sawtooth and Pashimeroi salmon hatcheries, which continue to operate.

“The pathogen is already out there in the watershed,” explained Hauck. “We can rear fish in the hatchery, and have them in better health than the fish in the wild, providing the fish are reared for a period of time in uncontaminated well water.”

Whirling disease is believed to have come from Europe, MacConnell said, arriving in frozen fish fillets in the 1950s. The fillets could have been ground up into fish food for use at eastern fish hatcheries.The spores must open in order to infect the common worm that, in turn, infects the fish.

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MEMO: This sidebar appeared with the story: Disease update Fish pathologist Beth MacConnell will speak on whirling disease in Idaho at the Pacific Northwest Fish Health Protection Committee meeting Oct. 5 at the Coeur d’Alene Holiday Inn. Her 10:30 a.m. talk will be preceded by a 9:30 update of the Madison River situation, where the rainbow trout population has dropped 90 percent.