Newly hatched larval sea lampreys are freshwater filter-feeders that consume detritus, algae, and other organic material found at river bottoms. Once in a saline environment (or in the Great Lakes), sea lampreys develop parasitic abilities, attach themselves to a fish and ingest their blood and skin. Sea lampreys ultimately breaks down the fish while the fish is still alive. This species is capable of attaching itself to a variety of species of fish and does not seem to have a preference of host species. Once sea lampreys reach sexual maturity, they no longer feed.
Animal Foods: fish; blood; body fluids; carrion
Plant Foods: algae
Other Foods: detritus
Foraging Behavior: filter-feeding
Primary Diet: carnivore (Piscivore , Sanguivore , Eats body fluids); herbivore (Algivore); omnivore ; detritivore