Institute for Fisheries Research Report No. 1775, 1971

Michigan Department of Natural Resources
Institute for Fisheries Research Report No. 1775, 1971
The Spread of Whirling Disease, Myxosoma cerebralis, into Native Trout Populations in Michigan

Warren G. Yoder

Abstract.-Whirling disease of salmonids, caused by Myxosoma cerebralis, was discovered in north-central Michigan in 1968. Examinations of trout 2 years later revealed that this disease had spread from infected rainbow trout (Salmo gairdneri) in the hatchery to native brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta). These infected native trout were collected from the 6-7 miles of stream below the infected source. Brook trout had a higher incidence of whirling disease than did the brown trout, although both species were in nearly equal abundance.