River Lamprey
Lampetra fluviatilis
Length 30cm

Migratory, adults moving upstream from sea in winter and spring to spawn on gravel beds in rivers. After spawning, adults die but eggs hatch into larvae which spend several years buried in river silt. Following metamorphosis to adult stage, they move to sea until maturity drives them to repeat cycle. Adult attaches to fish with toothed sucker to feed on blood; also eats carrion.