Montana State University

Whirling disease researchers find hope in Montana reservoir

May 23, 2005 -- By Evelyn Boswell, MSU News Service


Leah Steinbach Elwell, whirling disease researcher, sorts worm samples on the Madison River in southwest Montana. (Photo courtesy of Julie Alexander, MSU).    High-Res Available

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Rainbow trout in a Madison County reservoir have given a glimmer of hope to researchers trying to understand and stem whirling disease in Montana, says the state's whirling disease coordinator.

"They are not absolutely resistant, but they are significantly resistant," Richard Vincent said about rainbow trout that swim in the Willow Creek Reservoir three miles east of Harrison. Vincent works for Montana Fish, Wildlife and Parks at Montana State University.

Researchers haven't found a solution for whirling disease in Montana, but the trout warrant continued study, Vincent said. The encouraging strain of fish came from Wyoming between 1977 and 1981. Before that, the fish came to Wyoming from California.

Some of the rainbow trout in the Willow Creek Reservoir have been sent to scientists in Utah, California and Colorado, Vincent said. One research project on the fish received funding in the latest round of grants announced by the Montana Water Center, the National Partnership for the Management of Wild and Native Coldwater Fisheries, and the U.S. Fish and Wildlife Service. Ten research teams together received $644,000 for whirling disease studies in 2005-06. The Montana Water Center is housed at MSU.

Whirling disease has spread across most of the state since it appeared in Montana in 1994,Vincent said. Now infecting more than 130 streams, the disease is most rare in the Kootenai drainage in northwest Montana.

Whirling disease has been hard to conquer because its complex life cycle is hard to interrupt, said Liz Galli-Noble, program director for the Whirling Disease Initiative at the Montana Water Center.

The disease has two hosts and primarily strikes rainbow trout in their first two months of life. A parasite called Myxobolus cerebralis enters fish through their skin, then attacks cartilage and places pressure on the nervous system. Resulting deformities cause some fish to whirl. When the fish die, spores from the parasite enter the water and are eaten by tiny worms called Tubifex tubifex. The spores change form inside the worm and are released into the water. They attach themselves to fish, and the cycle continues.

"I don't know if there's ever going to be something like a cure. Our best bets lie in management control and preventing further infection," said Amy Rose, outreach program coordinator for the Whirling Disease Initiative.

Finding or developing resistant fish looks like one promising area for research, Rose said. That and other approaches were funded for 2005-06. Four of the 10 projects are headed by Montana scientists. The others involve researchers from Oregon, Colorado and Utah. All the projects are administered by the Montana Water Center.

Montana grant recipients are:

* Chris Guy and Alexander Zale of the Montana Cooperative Fishery Research Unit and Travis Horton, Montana Department of Fish, Wildlife and Parks, received $56,648 to study the movements of anglers in Montana and the implications for transferring whirling disease among drainages.

* Billie Kerans of MSU and Todd Koel of Yellowstone National Park received $72,483 to look at the risk of whirling disease to Yellowstone cutthroat trout as it relates to the abundance and susceptibility of host worms.

* Kerans and Vincent received $74,345 to analyze the risk of whirling disease across multiple scales.

* Koel and Kerans received $59,415 to study the viability of parasite spores after they pass through the digestive system of fish-eating birds in the Greater Yellowstone Ecosystem.

Out-of-state grant recipients are:

* Jerri Bartholomew, Oregon State University, and Antonio Amandi, Oregon Department of Fish and Wildlife, received $61,313 to resolve uncertainties in the introduction and establishment risks of the whirling disease parasite.

* Deb Cartwright, Vicki Blazer and W. Bane Schill of the National Fish Health Research Laboratory received $83,070 to study the effect of invertebrate populations in the silty, clay environment along river banks, riparian zones and water quality on Tubifex tubifex infection rates.

* Brett Johnson, Daniel Gibson-Reinemer, and Gregory Whitledge, Colorado State University; Patrick Martinez, Colorado Division of Wildlife; and Dana Winkelman, Colorado Cooperative Fish and Wildlife Research Unit, received $64,696 to track sources of illegally stocked trout that tested positive for whirling disease.

* Eric Wagner and Chris Wilson, Utah Division of Wildlife Resources, received $83,816 to study whirling disease resistance patterns of rainbow trout in the Willow Creek Reservoir.

* Winkelman and Barry Nehring, Colorado Division of Wildlife, received $31,758 to assess the density and distribution of Tubifex tubifex lineages in Windy Gap Reservoir, Colo.

* Winkelman and Kevin Thompson, Colorado Division of Wildlife, received $76,247 to investigate competition among Tubifex tubifex lineages and the potential for biological control of whirling disease in natural streams.

Evelyn Boswell, (406) 994-5135 or evelynb@montana.edu