Sea Lamprey Lifecycle
The sea lamprey has a complex lifecycle consisting of several stages. Sea lamprey begin life in Great Lakes streams as non-parasitic larvae that filter feed on plankton and detritus for three to ten plus years depending on environmental conditions and growth. Larval sea lamprey then begin a dramatic metamorphosis developing eyes and oral disks and tongues covered with pointy teeth and begin migrating downstream to the lakes. Once larval sea lamprey have metamorphosed and migrated to the lakes, they become parasitic juveniles and feed on the blood of host fish for twelve to eighteen months. During the winter or early spring, juvenile sea lamprey stop feeding and begin searching for suitable spawning streams. Upon finding and entering a suitable spawning stream, sea lamprey sexually mature into spawning adults, reproduce during the spring and early summer, and die shortly after spawning.