The sea lamprey is native to the Atlantic Ocean, where it feeds parasitically on a large number of fish species, many of which are considered important in human fishing and harvesting. Sea lampreys are jawless and feed by rasping their many teeth against the flesh of their host until they can burrow inside the body and feed on its soft innards.
Sea lampreys migrated inland by methods unknown as early as 1835 when they were discovered in Lake Ontario. Since then they have become a major invasive species and posed an extreme risk to the health of many fish and wildlife populations dependent on the water for life.
Sea lampreys parasitic to the St. Marys River region breed in the river and follow it to several major lakes including Lake Michigan and Lake Huron. Once they reach the lakes they feed, infest and breed in a dangerous cycle unsupported by the local lake ecology in either location.
A single sea lamprey can kill up to forty pounds worth of fish over the course of its adult life. They feed on blood and other fluids, damaging the health of fish like chub, whitefish and lake trout and reducing their ability to breed effectively and to form stable populations.