Researchers are analyzing water samples from rivers that feed into the Great Lakes.
They’re looking for signs of Asian carp, the huge, voracious invasive fish that could alter the lakes’ ecosystem, if the fish get into the lakes.
The U.S. Fish and Wildlife Service collected 200 water samples last month from the Kalamazoo River in Michigan. Officials say no genetic material from Asian carp was captured.
Additional Great Lakes tributaries have been sampled. Results from those tests are scheduled to be released later this year.
Asian carp DNA previously has been detected in Chicago-area waterways, as close as seven miles from Lake Michigan.