Sea lampreys have been in the Great Lakes for decades. In the middle of the 20th Century, the invasive species nearly wiped out lake trout and other fish. The U.S. Fish & Wildlife Service will begin testing the Detroit River for sea lampreys on Wednesday, June 3. Crews in boats will treat the bottom of the river with a special chemical. Then they’ll collect and count any lamprey larvae that emerge from the muck. Scott Grunder supervises the Fish & Wildlife Service’s biological station in Ludington, Michigan. He says the last time researchers surveyed the river in 2013, they didn’t find any lampreys. Grunder tells WDET’s Pat Batcheller that’s surprising considering how widespread the creatures are throughout the Great Lakes.
Watch the video “Silent Invaders” from the U.S. Fish & Wildlife Service’s YouTube channel here: