Ruffe (Gymnocephalus cernuus)

photo by John Lyons, WI DNR

Native to Eurasian, the Ruffe entered the Great Lakes in the ballast water of oceangoing vessels around 1985. The ruffe is a member of the perch family that may be confused with young native fish such as yellow perch and walleye. Ruffe average 4-6 inches in length and tend to be quite spiny, which helps to distinguish them from other species. Scaless heads with permanent “frowns” also helps to separate them from native perch species. Ruffe compete with native fish for food and habitat, and populations have the potential to increase rapidly.

Because ruffe could spread to inland waters, Wisconsin has developed laws on its catch and transport.

If you catch a ruffe (outside the Duluth area of Lake Superior and the St. Louis estuary), kill it, freeze it, and call one of the following before transporting: Wisconsin Sea Grant program in Manitowoc, (920) 683-4697; U.S. Fish and Wildlife Service in Ashland, (715) 682-6158: or a local DNR office. DO NOT THROW IT BACK ALIVE

Links and Publications

• WI Fishing Seasons and Regulations
• Wisconsin Lakes Book: Ruffe

Links and Publications[exit DNR]

• Distribution Map (USGS)
• Eurasian Ruffe USGS Upper Midwest Environmental Sciences Center
• Eurasian Ruffe UW Sea Grant
• Ruffe Fish of the Great Lakes, Wisconsin Sea Grant
• Ruffe: a new threat to our fisheries Invasive exotic species, Minnesota Sea Grant
• Ruffe ID card Invasive exotic species, Minnesota Sea Grant
• Ruffe in the Great Lakes Region Great Lakes Information Network (GLIN)
• Species Profiles: Eurasian ruffe Invasivespecies.gov
• Ruffe Some Nonindigenous Aquatic Species of Concern, Aquatic Nuisance Species Task Force
• Gymnocephalus cernuus (Linneaus 1758) Nonindigenous Aquatic Species, United States Geological Survey (USGS)
• Gymnocephalus cernuus Global Invasive Species Database
• Ruffe, A New Threat to our Fisheries [PDF] Ohio Sea Grant