Product kills whirling disease spores

Whirling disease-infected trout exhibit a tail-chasing behavior.

August 19, 1999
Web posted at: 1:25 p.m. EDT (1725 GMT)

The Scott Fly Rod Company will soon market a product that will allow anglers and hunters to actively participate in controlling the spread of whirling disease in America's wild trout streams.

The Environmental Protection Agency recently approved the company's new product, BrightWater, which kills whirling disease spores on contact. The product is sprayed directly on fishing and hunting gear.

"BrightWater is in fluid form — an eight ounce spray bottle that you spray on your gear after you get out of the water. If whirling disease spores are on your gear it prevents the transfer from river to river," said John Duncan, marketing director for Scott Fly Rod Company, Montrose, Colo.

"BrightWater allows two things. It allows each individual fisher and hunter to take personal responsibility for not spreading the disease and equally important, we will donate a percentage of BrightWater revenues to whirling disease research in hopes that we can eradicate it all together," said Duncan

Whirling disease is caused by a microscopic parasite known as Myxobolus cerebralis and only affects certain species of trout, salmon and whitefish. The tiny parasite enters the body of the tubifex worm in the streambed. Fish become infected after the parasite leaves the worm and enters the water. The parasite attaches to a fish and grinds its way down into the fish's cartilage where it matures into the whirling disease spore. It lives there until the fish dies and the whole cycle is repeated when the spores are released back into the water.

Usually, the disease affects young fish by damaging their cartilage and nerves. Some infected fish demonstrate an abnormal whirling or tail-chasing pattern. Other abnormalities in young fish include a black tail and adult fish sometimes have a deformed head or body.

"Whirling disease affects the majority of rainbow trout in many of Montana and Colorado's famous streams like the Madison in Montana and the Gunnison and Colorado Rivers," said Duncan. It has also been found in Yellowstone Lake in Yellowstone National Park.

Studies show rainbow and cutthroat trout are more susceptible to the disease than brown trout, which appear to be immune to whirling disease. Studies in Montana and at the University of California-Davis show grayling and bull trout are also very resistant to the parasite infection. Research on all aspects of whirling disease is on going.

The disease can be spread many ways: moving live infected fish or parts of fish, infected birds that pass the parasite on to fish and contaminated gear like waders and boats.

"For years fishermen and women have been stepping in bleach after fishing in rivers that have whirling disease," said Duncan. But bleach is harmful to the environment. "BrightWater will not eradicate whirling disease but it will prevent it from being spread if it's used properly."

All 50 states are in the process of approving BrightWater, which has been classified as a pesticide by the EPA.

"We will distribute it broadly in outdoor-related stores. Here in the Rocky Mountains, that could mean in convenience stores. Whirling disease affects anyone who's in the water-it threatens their recreation," said Duncan.

The active ingredient in BrightWater is dimethyl benzyl ammonium chloride. "Studies show it kills the whirling disease spore in concentrations of 800 parts per million. We used it at concentrations of 2000 ppm to make it more potent. We also added citronella oil to make it smell good, that probably will make it a highly effective bug spray," said Duncan.

Copyright 1999, Environmental News Network, All Rights Reserved

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