Zebra mussels, which can disrupt native ecosystems and food chains, have been moving into the Midwest since the late 1980s. The first established population was found in 1988 in Lake St. Clair, which connects to Lakes Huron and Erie. Since then, they have also moved up the Mississippi and Illinois rivers into Wisconsin and Minnesota.
Source: U.S. Geological Survey; Nonindigenous Aquatic Species database
Photo by AMY BENSON • U.S. Geological Survey