The sea lamprey is native to the Atlantic Ocean, but was introduced to the Great Lakes through locks and shipping canals in the 1800s. The sea lamprey was first discovered in Lake Ontario in 1835, and it spread to Lake Erie by 1921, Lake Huron by 1932, Lake Michigan by 1936, and Lake Superior by 1946. The sea lamprey had become established and had viable populations in all of the upper lakes by 1947 (1).
The sea lamprey is parasitic, preying upon the blood and body fluids of adult fish. They scar and often kill the fish, and sometimes up to 6 out of 7 fish they attack will die (19). Sea lamprey prey upon many fish species, including commercially important ones. In the 1940s and 1950s, sea lamprey predation contributed to the collapse of the lake trout, whitefish, and chub fisheries. Annual catches of lake trout in Lakes Huron and Superior dropped from 15 million pounds to 300,000 pounds by the early 1960s (19). Sea lamprey populations have been reduced by 90% in most areas due to chemical control programs coordinated by the Great Lakes Fishery Commission, Fisheries and Oceans in Canada, the USFWS, U.S. Army Corps of Engineers. However, the St. Marys River is still considered a “hot zone.”
