Ed Golson Outdoor Education

sea lamprey

Scientific Name: Petromyzon marinus

Description: Sea lampreys are eel-shaped fish that have a dark blue or gray back and a silvery-white underside. Adult lampreys grow to be between 12 and 20 inches in length and weigh a little less than a pound. The adult form of the lamprey has a mouth that is lined completely with teeth and is shaped like a suction cup. 

Each year, the lampreys swim up streams and lay up to 60,000 eggs. These eggs hatch into very small, blind, toothless larva. The larva survive by eating the food they filter through their gills . After a few years of hiding in streambeds, the larva metamorphoses into their adult forms complete with eyes and teeth and swim into the lakes. 

Habitat: Sea lamprey's are originally from the Atlantic Ocean, but they began invading the Great Lakes through the Erie Canal in 1819. They are now found all throughout the Great Lakes region.  

Why it's a problem :  It's the adult lampreys that cause all the problems. The lamprey is a parasite on other fish. It uses its special jaw to attach to the sides of larger fish such as lake trout and salmon. The lamprey then starts sucking on the fish to eat its blood. It stays attached to the larger fish until the other fish dies from loss of blood or the lamprey is full. If lamprey populations are not tightly controlled, they can multiply very quickly which can put a large dent in the populations of trout and salmon.

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