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Invasive Species: Eurasian Ruffe

Invasive Species: Eurasian Ruffe

Eurasian Ruffe

(Gymnocephalus cernuus)
*Established in Michigan*

PROHIBITED IN MICHIGAN

Report this species:

Use the Midwest Invasive Species Information Network (MISIN) online reporting tool.

- Or - download the MISIN smartphone app and report from your phone - MISIN.MSU.edu/tools/apps/#home.

 

Identification:

  • Olive-brown back side and yellow-white belly.
  • Fused dorsal fins with no notch, dark spots on membranes between the rays of the fin.
  • About 25 cm. in length.
  • Small, downturned mouth.

Eurasian Ruffe
Illustration by Joseph R.  Tomelleri 

Eurasian Ruffe
Photo courtesy of Gary Cholwek, U.S. Geological Survey. Bugwood.org.

Habitat: Ruffe are bottom dwelling fish that inhabit fresh and brackish waters. They appear to do well in a variety of habitat types, but abundance appears to be correlated with eutrophication and nutrient inputs.

Diet: Diet consists of mainly aquatic insects, but Eurasian ruffe will occasionally consume the eggs of other fish. A well-developed sensory system allows this species to feed at night. They have a few natural predators and the ability to hunt at night further reduces the risk of predation.

Native Range: Northern Europe and Asia.

Local Concern: The reduced risk of predation from hunting at night and having few natural predators in the United States makes them successful invaders.

Means of Introduction: Most likely ballast water from transoceanic vessels.

Other Common Names: ruffe, river ruffe, pope.

Native look-alikes and how you can tell them apart from Eurasian ruffe:

  • Walleye: Dorsal fins separated, bottom of caudal fin has white tip, large mouth.
  • Sauger: Dorsal fins separated, large mouth.
  • Yellow perch: Dorsal fins separated, no distinct spots on dorsal fin, dark vertical stripes.

MORE INFORMATION:

Status and Strategy for Eurasian Ruffe Management This document provides in-depth information about Eurasian Ruffe in the State of Michigan including identification, distribution, management, and control options.

Eurasian Ruffe Invasive Species Alert (printable PDF)