Sea Lamprey (Petromyzon marinus)

Sea lamprey are primitive, jawless fish native to the Atlantic Ocean. Like salmon and alewife, sea lamprey are native ocean fish that spawn in fresh water. Historically, sea lamprey have enhabited Lake Ontario and the St. Lawrence River, as they are open to the Atlantic Ocean. In 1921, lampreys appeared in Lake Erie for the first time, arriving via the Welland Canal, which was constructed for ships to avoid Niagara Falls on their way up the St. Lawrence Seaway. Shortly thereafter, sea lamprey quickly populated all of the upper Great Lakes.

The sea lamprey is an aggressive parasite with a toothed, funnel-like sucking mouth and rasping toungue which is used to bore into the flesh of other fishes to feed on their blood and body fluids. A single lamprey will destroy up to 40 pounds (18 kilograms) of fish during its adult lifetime. Sea Lamprey are so destructive that, under some conditions, only one out of seven fish attacked will survive. In the 1940’s and 1950’s, sea lamprey populations exploded in the Great Lakes which contributed significantly to the collapse of fish species that ere an economic mainstay of a vibrant Great Lakes fishery.

photo of sea lamprey

Sea lamprey attached to a lake trout

Currently the Great Lakes Fishery Commission, in cooperation with Fisheries and Oceans Canada and U.S. Fish and Wildlife Service spend millions of dollars annually to control the sea lamprey population in the great lakes. Ongoing control efforts have been very sucessful, as a 90% reduction of sea lamprey populations in most areas has been achieved. This has created a healthier environment for fish survival and spawning.

General Characteristics

  • Sea lamprey are generally 12 to 20 inches long
  • They weigh 8 to 13 ounces each
  • Sea lamprey are greyish blue-black with metallic violet on their sides with silver white coloration on the underside

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