Whirling Disease Information
Recently, the health of some of the trout within the Centennial Valley, particularly Red Rock Creek, has been threatened by whirling disease. Though first documented in the United States in 1956, the disease was only discovered in Montana in late 1994. Whirling disease is caused by the parasite, Myxobolus cerebralis, which attacks the skeletal structure of salmonids (trout, salmon, and grayling) and causes them to swim in circles. It does this by lodging in and deforming the cartilage of young fish. The deformity becomes permanent when the cartilage turns to bone, resulting in curved spines and head deformities which in turn cause nerve damage. The infected fishs whirling behavior is the result of this nerve damage. Although the whirling may not directly kill a trout, an infected fishs erratic tail chasing makes it more vulnerable to predation and also makes feeding difficult, potentially leading to starvation and death. In the Centennial Valley, brook and hybrid rainbow-cutthroat trout have been found infected with whirling disease.
Although there are no human risks associated with eating affected trout, people can contribute to the spread of this disease. Recently, a Whirling Disease Initiative was established between Montana State University and the U.S. Fish and Wildlife Service for the National Partnership on the Management of Wild and Native Cold Water Fisheries (administered by the Montana University System Water Center). For more information on whirling disease, its management, and what you can do to control its spread, contact the website below and websites related to Refuge Management.