Great Lakes Environmental Directory Great Lakes Great Lakes environment Great Lakes grants exotic species water pollution water export drilling environment Great Lakes pollution Superior Michigan Huron Erie Ontario ecology Great Lakes issues wetlands Great Lakes wetlands Great Lakes Great Lakes environment Great Lakes watershed water quality exotic species Great Lakes grants water pollution water export oil gas drilling environment environmental Great Lakes pollution Lake Superior Lake Michigan Lake Huron Lake Erie Lake Ontario Great Lakes ecology Great Lakes issues Great Lakes wetlands Great Lakes Resources Great Lakes activist Great Lakes environmental organizations Great Lakes Aquatic Habitat air pollution alien species threatened rare endangered species ecological Great Lakes information Success Stories Great Lakes Directory Home/News Great Lakes Calendar Great Lakes jobs/volunteering Search Great Lakes Organizations Take Action! Contact Us Resources/Links Great Lakes Issues Great Lakes News Article About Us Networking Services

Great Lakes Article:

Eurasian Ruffe May Increase Pressure on Lake Michigan Yellow Perch


Eurasian ruffe, an invasive fish whose numbers have multiplied dramatically in Lake Superior, have now been spotted in northern parts of Lake Michigan. The good news is that round gobies, which are already abundant in Lake Michigan, may keep ruffe numbers down. The bad news is that Eurasian ruffe will nonetheless deplete resources for yellow perch, an important native sport fish.

With funding from Illinois-Indiana Sea Grant, Gary Lamberti, University of Notre Dame, and Martin Berg of Loyola (Ill.) University have been studying the relationship among Eurasian ruffe, round gobies and zebra mussels, and how this "exotic triad" can affect yellow perch. "Exotic species now dominate the food webs of the Great Lakes, including Lake Michigan," says Lamberti.

The researchers found that although the relationship between these invaders is complex, one fact is simple. The successful species is often the one that gets there first, noting that in Lake Superior Eurasian ruffe have become the dominant fish, while in Lake Michigan, round gobies have become numerically dominant, relegating ruffe to deeper waters.

Yellow perch in Lake Michigan are pressured early in life by competition from zebra mussels and round gobies. Zebra mussels filter plankton that larval perch need to grow. Gobies not only eat yellow perch eggs, they also compete with young perch for invertebrate food. Even a diminished ruffe presence will further impact the young perch.

As yellow perch grow larger they move to deeper waters, as do ruffe. Unlike larger yellow perch, ruffe prefer the bottom habitat, but nonetheless the two species will continue to tap the same food sources.

"The addition of Eurasian ruffe to Lake Michigan waters will likely increase the bottleneck on yellow perch," said Lamberti. "The native fish will experience increased competition during several stages of its life."

Contact: Gary Lamberti, Illinois-Indiana Sea Grant Researcher, Associate Professor of Biology, University of Notre Dame; Phone: (574) 631-8075; E-mail:
Martin Berg, Illinois-Indiana Sea Grant Researcher, Assistant Professor of Biology, Loyola (Ill.) University; Phone: (773) 508-8853; E-mail:

This information is posted for nonprofit educational purposes, in accordance with U.S. Code Title 17, Chapter 1,Sec. 107 copyright laws.
For more information go to: If you wish to use copyrighted material from this site for
purposes of your own that go beyond "fair use," you must obtain permission from the copyright owner.

Great Lakes environmental information

Return to Great Lakes Directory Home/ Site Map