Sea Lamprey (Petromyzon marinus)

photo by Great Lakes Sea Grant Network

Sea lampreys (Petromyzon marinus) are primitive, jawless fish native to the coastal regions of the Atlantic Ocean. Unlike other fish that are found in and around Wisconsin, they possess no scales, paired fins, swim bladders, or bones.

Until 1919, sea lampreys were prevented from entering the Great Lakes by Niagara Falls, which acted as a natural barrier. When the Welland Canal was deepened, it became possible for ships, as well as the sea lamprey, to bypass the falls and enter the Great Lakes. By 1938 the sea lamprey had invaded all of the Great Lakes, contributing to the collapse of the whitefish and lake trout fisheries.

Each sea lamprey can destroy up to 40 pounds of fish in its lifetime. Their specialized mouths allow them to attach to the sides of host fish to feed on body fluids.

Sea lamprey populations in the Great Lakes are currently kept in check through aggressive control using several methods, including lampercide application, barrier installation, sterile-male release, and trapping.

Links and Publications

• EEK! Environmental Education for Kids

Links and Publications [exit DNR]

• Distribution Map (USGS)
• Petromyzon marinus Linnaeus 1758 Nonindigenous Aquatic Species, United States Geological Survey (USGS)
• Photo on lake trout (SGNIS)
• Sea Lamprey control Fisheries and Oceans Canada, Bayfield Institute
• Sea Lamprey USGS Great Lakes Science Center
• Sea Lamprey: the battle continues published by Ontario Federation of Anglers and Hunters, MN Sea Grant Site
• Sea Lamprey Fish of the Great Lakes, Wisconsin Sea Grant
• Sea Lamprey in the Great Lakes Region Great Lakes Information Network (GLIN)
• Species Profiles: Sea lamprey Invasivespecies.gov
• Petromyzon marinus Global Invasive Species Database