The study was performed in response to a proposal to transfer bull trout Salvelinus confluentus from the Clark Fork River downstream of Cabinet Gorge Dam to areas upstream. The Survey found R. salmoninarum to be an enzootic fish pathogen in the lower Clark Fork River drainage and that the exposure of introduced bull trout and other salmonids would be similar both above and below Cabinet Gorge Dam. Fishery managers concluded that passage of a limited number of bull trout collected below Cabinet Gorge Dam should pose no significant risk of increasing the distribution or prevalence of the pathogen and disease above the dam. The documentation of Myxobolus cerebralis in cutthroat trout in Yellowstone Lake by the Bozeman Fish Health Center provided the National Park Service and its partners with an early warning of another potential threat to the lake's cutthroat trout populations and fishery. The discovery of Myxobolus cerebralis will likely compound management problems associated with a developing exotic population of lake trout.
Lake trout are generally resistant to whirling disease.
Whirling disease is caused by the myxosporidian parasite Myxobolus cerebralis, which is endemic to Europe. Recent losses of wild trout in Colorado in 1993 and in Montana in 1994 have had significant ecological and economic implications in both States. The losses have also raised the Nation's awareness of just how little is known about this disease. The effectiveness of ozonation of hatchery water supplies as a control tool. Host-parasite relationships and environmental preferences of the oligochaete, Tubifex tubifex, to develop alternative management strategies.