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Invasive Species: Sea Lamprey

Sea Lamprey

(Petromyzon marinus)
*Established in Michigan*


  • Eel-like body.
  • 2 close dorsal fins.
  • 7 gill openings.
  • Large round mouth with sharp, curved teeth and rasping tongue.
  • Landlocked individuals are usually about 64 cm in length.

sea lamprey
Photo courtesy of T. Lawrence, GLFC.

sea lamprey
Photo courtesy of John Lyons.

sea lamprey
Photo courtesy of Lee Emery, U.S. Fish and Wildlife Service.

Habitat: Sea lamprey are cartilaginous, jawless fish that are generally marine and ascend freshwater rivers to spawn.

Diet: As adults, lamprey are parasitic and feed on the body fluids of other fishes, often killing them. Larval lamprey, also called ammocoetes, burrow into sediment and live for up to ten years as filter feeders.  

Native Range: Atlantic coast from Labrador to Gulf of Mexico, Florida and the Atlantic coast of Europe and the Mediterranean Sea.

U.S. Distribution: Sea lamprey are found in all five Great Lakes as well as some tributaries in Illinois, Indiana, Michigan, Minnesota, New York, Pennsylvania, and Wisconsin.

Local Concern: Sea lamprey have a high reproductive potential, a lack of predators, and an ideal habitat in Michigan waters. An established population of sea lamprey has had a devastating effect on the state’s fishery.

Means of Introduction: It is argued whether sea lamprey are native to Lake Ontario. Regardless, the species in not native to the other Great Lakes and was introduced to Lake Erie through the Welland Canal.


Sea Lamprey Invasive Species Alert - Printable PDF