Whirling Disease: New TU Report on the “State Of The Epidemic”
Updated Report Documents New Research and Continuing Challenges Facing Fisheries Conservationists
2/17/1999 — — Trout Unlimited today released a comprehensive new report detailing the current knowledge about whirling disease, the parasitic infection that has been linked to dramatic declines in wild trout populations in several Western rivers.
Whirling Disease in the United States, a major update of TU’s groundbreaking 1995 report on whirling disease (WD) in America, summarizes what has been done to better understand WD and its implications for wild trout fisheries nationwide, and updates the state of whirling disease science. The report is the most complete synthesis of the science and management of Myxobolus cerebralis since 1995, when the discovery of WD in wild trout in Montana and Colorado spurred accelerated research into the disease and its effects.
“Researchers must continue to move forward on the research priorities already identified, and assess possible management strategies and their effectiveness in the wild,” said Charles Gauvin, President and CEO of Trout Unlimited. “New knowledge about the importance of habitat degradation (in providing Tubifex habitat), environmental stress, and disease “point sources” all suggest that our ability and willingness to protect and restore our streams and rivers may prove the best long-term protection against whirling disease.”
Significant research results described in the report include new evidence that the Tubifex worms that carry WD appear to thrive in polluted or degraded streams. Studies of T. tubifex worms in Montana found that worms are primarily found in polluted sites where normal benthic community diversity had been reduced.
Research in Colorado has found infection “point sources” – locations where production of triactinomyxons (the spores that cause the disease) is especially high and disease is especially severe.
Researchers have also developed a DNA-based test to detect the parasite, and have established that most salmonid fishes are susceptible to the infection, to varying degrees. Key research has also focused on the role of water temperature on the numbers of disease spores found in a given stream or water body.
Whirling Disease in the United States also documents the investments in research and the changes in fisheries management that many states have made in the wake of the WD crisis, singling out Colorado, Idaho, Utah, and Montana as examples, while pointing out that much remains to be done to safeguard remaining wild trout populations and prevent further spread of the disease.
The TU report also points out the contradictory actions taken by federal agencies in dealing with whirling disease. The U.S. Fish and Wildlife Service (USFWS) has supported research at several top laboratories and has also supported a competitive grants program through the National Partnership on the Management of Wild and Native Cold Water Fisheries. The National Partnership has provided over $920,000 in competitive grants to support whirling disease research, leveraging over $880,000 in matching funds.
By contrast, U.S. Forest Service and Bureau of Land Management have been less helpful. In 1988, the Forest Service prepared an Environmental Assessment that permitted the stocking of fish infected with whirling disease on Forest Service and BLM lands. It is the current policy of the Forest Service and the BLM that if a state wishes to stock fish exposed to whirling disease on public lands, it may do so without additional environmental review.
Copies of Whirling Disease in the United States may be obtained upon request from Trout Unlimited (703) 522-0200, and may be downloaded in Adobe .pdf format from TU’s web site at http://www.tu.org/library/conservation.asp
Publication of Whirling Disease in the United States was made possible by the generous contributions of the Roy Hunt Foundation, the Cleveland Trout Club, John Lutz III, and individual members of TU’s Coldwater Conservation Fund.
Founded in 1959 in Grayling, Michigan, Trout Unlimited is America’s leading coldwater fisheries conservation organization. TU’s 100,000 members in 455 chapters nationwide are dedicated to the conservation, protection, and restoration of North America’s trout and salmon and their watersheds.