Scientists say genetic material from an invasive fish called the Eurasian ruffe has been detected in southern Lake Michigan for the first time.
The Eurasian ruffe is related to the yellow perch. The exotic species is found in Lake Superior and parts of northern Lake Huron and Lake Michigan.
Scientists with The Nature Conservancy, the University of Notre Dame and Central Michigan University discovered DNA from the ruffe in two water samples taken in July from Lake Michigan's Calumet Harbor at Chicago.
Although no live ruffe have been found in the area, Lindsay Chadderton of The Nature Conservancy says officials should search for them. He says if they spread through the Chicago waterway system, they eventually could invade the Mississippi River watershed and compete with native fish species there.