"Whirling disease" is a disease of salmonids, the family of fish that includes trout, salmon, and whitefish. Whirling disease is caused by a microscopic parasite known as Myxobolus cerebralis and gets its name from the abnormal whirling or tail-chasing behavior exhibited by some infected fish. Other symptoms include a blackened tail and head or spinal deformities. Most species of salmonids are susceptible to whirling disease infection and, particularly in young fish, the disease can cause high mortality rates. Learn more about this disease from the Whirling Disease Initiative.

The Whirling Disease Initiative was established by Congress in 1997 to conduct research that will lead to practical methods of managing wild trout fisheries. To date, the Initiative has funded more than 120 projects conducted by university members, public agency scientists, and private firms with great success. Researchers have investigated the parasite's complex life cycle and factors that influence its spread and severity. Because eradication of whirling disease is unlikely, the Initiative focuses on research that develops practical management solutions to maintain viable, self-sustaining wild trout fisheries in the presence of the whirling disease parasite.