• Biodiversity Sea Lamprey
  • Sea Lamprey

    Petromyzon marinus

    A Primitive Fish

    The Sea Lamprey belongs to a group of fishes called Lampreys. They are by far some of the most primitive fish, along with hagfish. They are called cyclostomes, meaning ’round mouths’ which refers to their lack of jaws. Instead of jaws, sea lamprey have a round, sucker mouth full of many grasping teeth. Sea lampreys also lack bone. Instead they have a skeleton of cartilage.

    Anadromous Fish

    Just like Salmon and Alewives, the Sea Lamprey is a fish that swims into freshwater to breed. There are lampreys that never migrate to the ocean, though.

    An Invasion

    In 1835 the fish was introduced to Lake Ontario. In 1921 the Sea Lamprey invaded Lake Erie via the Welland Canal. They rapidly conlonized the lake and are causing big problems with the fisheries. They have large infestations now in Lake Michigan and Lake Huron and reports by scientists are that one lamprey can eat up to 40 pounds of fish in a year.

    Control of the Sea Lamprey

    Sea Lampreys reached peak numbers in the 1950s and scientists were working to find a way to control them. In 1958 they found the chemical TFM which selectively kills sea lamprey larvae in the spawning grounds. This chemical has now decreased the numbers of lampreys to about 10 percent of their peak poplulation. The worry today, however, is that the surviving lampreys may develop a resistance to the chemical or begin breeding in deeper wates, where the lampricide is not effective.

    More information

    Alien Profile: Sea Lamprey
    Wisconsin Department of Natural Resources

    International Sea Lamprey Management on the St. Mary’s River: Everyone Wins…But the Sea Lampreys
    Great Lakes Fishery Commission

    Sea Lamprey: The Battle Continues
    Minnesota Sea Grant

    Sea Lamprey: A Great Lakes Invader
    Great Lakes Fishery Commission

    Sea Lamprey Assessment: Improving Control Through Better Understanding
    Great Lakes Fishery Commission

    Sea Lamprey Barriers: New Technologies Help Solve an Old Problem
    Great Lakes Fishery Commission

    Sea Lamprey Control
    Great Lakes Fishery Commission

    Sea Lamprey in the Great Lakes Region
    Great Lakes Information Network

    Sterile-Male-Release-Technique: An Innovative Sea Lamprey Control Method
    Great Lakes Fishery Commission

    TFM and Sea Lamprey Control: A Success Story
    Great Lakes Fishery Commission

    Related Topics

    Written by Rob Nelson

    Rob is an ecologist from the University of Hawaii. He is also an award winning filmmaker. As principle director of the Untamed Science productions his goal is to create videos and content that are both entertaining and educational. When he's not making science content, he races slalom kayaks and skydives.

    You can follow Rob Nelson