Sea lampreys in the Great Lakes of North America

The movement of sea lampreys into the upper Great Lakes (Superior, Michigan, and Huron) initiated a series of biological changes which have extended beyond the fish directly attacked by the parasite. The threat posed by the sea lamprey was not generally recognized until it was well established in all the lakes and had seriously affected the fisheries in Lakes Huron and Michigan. As the sea lamprey increased primarily at the expense of the valuable lake trout stocks and to a lesser degree other fish species, the need for research and concerted action became clear to the commercial fishery industry and fishery investigators of the United States and Canada.