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Upper Midwest Environmental Sciences Center

Eurasian Ruffe

Eurasian Ruffe
Why are they a problem?
Eurasian RuffeEurasian Ruffe Ruffe pose a threat to native fish because they
(1) mature quickly, (2) have a high reproductive capacity, and (3) easily adapt to new environments. Ruffe are more tolerant of poor water conditions and have several anatomical features (well developed sensory organs that allow them to detect vibrations given off by both predators and prey) that give them an advantage over native fishes. Native fish populations–especially yellow perch, emerald and spottail shiners, trout perch, and brown bullhead–have declined in locations where ruffe have become established.
Fast Facts 
How far have they spread?
Origin: Eurasia
Preferred habitat: Turbid lakes with soft bottoms and little or no vegetation. Also prefer rivers with slow moving waters.
Size: 4 to 6 inches
Method of introduction: Ballast discharges from ocean going vessels
Ruffe were first detected in western Lake Superior in 1986. The ruffe population has increased rapidly in the St. Louis River at Duluth-Superior and has spread to other rivers and bays along the south shore or western Lake Superior. They have also spread past the Ontonagon River in the Upper Peninsula of Michigan. They are now one of the most abundant fish in five tributaries: the Sand, Flag, Iron, Amnicon, and Brule Rivers. Ruffe have also been detected at Thunder Bay, Ontario, and Alpena, Michigan (Lake Huron).
What are UMESC scientists doing to help?
Researcher performing chemical analysis
Researcher performing
chemical analysis
The UMESC scientists are conducting research on various types of piscicides (chemicals that kill fish). They are attempting to develop piscicides that will kill ruffe but leave other fish unharmed. Recent studies have explored the effectiveness of using existing registered chemicals to control ruffe–for example, antimycin and rotenone (registered piscicides) and TFM and Bayluscide (chemicals approved for the control of sea lamprey).

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