Sea Lamprey
Petromyzon marinus
(Pet-ro-my-zon ma-reen-us)
These snake-like creatures are often mistaken for eels when they’re seen swimming through the water. The major difference between the two species is that lampreys have circular mouths filled with multiple rows of large teeth. Rather than biting and swallowing their prey, sea lampreys are parasitic feeders: They attach themselves to other fish with their teeth and suck their host’s blood and nutrients—like an underwater vampire! They’re usually around 3 feet long (1 m) and can weigh up to 5.5 pounds (2.5 kg).
Where They Live
Sea lampreys can be found in the Atlantic Ocean, in the waters surrounding Iceland, and in the western Mediterranean Sea. They’ve also been introduced to many other areas, often causing harm to local marine life in the process.
The sea lamprey can travel between bodies of water that have different salinities, or levels of salt. This makes them quite unusual—very few species of fish are able to survive in both saltwater and freshwater environments. In adulthood, they migrate from the ocean into rivers so they can reproduce.
What They Eat
Catfish, salmon, and rainbow trout are some of the fish the sea lamprey likes to feed on. A single lamprey can kill up to 40 pounds (18 kg) of these fish in its lifetime! Lampreys spend most of their days in groups, attaching to different hosts, but once they reach sexual maturity, they stop feeding altogether.
Conservation Status
Least Concern
Sea lampreys are seen as invasive pests by many people because of their negative impact on other fish, particularly those that are bought and sold for food around the globe. In fact, there’s an official program in place to decrease their numbers, with traps set up in the Great Lakes region of North America to keep the lamprey from causing further damage to other fish. It’s the only animal in this book that conservationists are actively trying to get rid of.
Fun Facts
