The Nature Conservancy has named sea lampreys one of the five “usual suspects” invading the Great Lakes basin.
These eel-looking parasites find a host and suck the life out of it. During the length of one life cycle, a sea lamprey can kill up to 40 pounds worth of fish and can grow up to 3 feet long.
Sea lampreys are native to the Atlantic Ocean, Lake Ontario and the St. Lawrence River. Though they are present throughout the Great Lakes region, control efforts have successfully reduced 90 percent of the sea lamprey population.