Southeastern Wisconsin Invasive Species Consortium, Inc.


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(Gymnocephalus cernuus)

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.

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