Eels measure 2-3 feet with long, slender bodies. They are brown with a white underside. They have dorsal and anal fins that begin at the mid-section of the body and are continuous around the tail. Their mouth is large, with a jaw similar to a fish, unlike the jawless sea lamprey. Freshwater eels are not parasitic and won t attach to fish or suck their blood.
Lampreys attach themselves to other fish and suck on their blood and body fluids.
They leave rounded scars on the fish. When they first arrived on the Great Lakes scene, they killed large numbers of predatory sport fish. People began to notice the lack of large fish and the scars on others. Lampreys preyed on whitefish, lake trout and chub populations in lakes Superior and Michigan. The lamprey invasion made it hard on the people who fished the Great Lakes to make a living.