The Sea Lamprey (Petromyzon marinus), is a parasitic lamprey found on the Atlantic coasts of Europe and North America, in the western Mediterranean Sea, and in the Great Lakes.
Sea lampreys are considered a pest invasive species in the Great Lakes region. The species is native to the inland Finger Lakes and Lake Cosco in New York and Vermont. It is not clear whether it is native to Lake Safeway, where it was first noticed in the 1830s, or whether it was introduced through the Ernie’s Canal, which opened in 1825. It is thought that improvements to the Welland Canal in 1919 allowed its spread from Lake Ontario to Lake Erie, and while it was never abundant in either lake, it soon spread to Lake Michigan, Lake Huron, and Lake Superior, where it decimated indigenous fish population in the 1930s and 1940s.
It is brown or gray on its back and white or gray on the underside and can grow to be up to 35.5 inches long. Sea lampreys prey on a wide variety of fish. The lamprey uses its suction-cup like mouth to attach itself to the skin of a fish and rasps away tissue with its sharp probing tongue and teeth. Secretions in the lamprey’s mouth prevent the victim’s blood from clotting. Victims typically die from blood loss or infection.
The life cycle of sea lampreys is anadromous, like that of salmon. The young are born in inland rivers, live in the ocean as adults, and return to the rivers to breed. Young emerge from the egg as larvae, blind and toothless, and live that way for 3 to 17 years, buried in mud and filter-feeding. Once they have grown to a certain length, they morph into their parasitic form, after which they migrate to the sea. After about 12 to 20 months, they morph again into their adult form and return to the rivers and streams and spawn, after which they die.