The study looked at migratory polymorphism of three species of lampreys in the Russian North. Petromyzon marinus, Lampetra fluviatilis and Lethenteron camtschaticum are capable of creating different ecological forms, and their individuals exhibit different forms of migration: downstream, feeding, and upstream. Larval migrations include primary dispersal and redistribution in the river system. Feeding migrations can take place in different areas, including desalinated ones, and those formed as a result of anthropogenic activities. Upstream migrations occur in both nonparasitic and parasitic forms. Migratory polymorphism is essential for the development of intraspecific variation and the adaptability of organisms to various environmental circumstances.