Sea Lamprey migration: A millenial journey

The lampreys are a very ancient lineage of vertebrates, with the fi rst recognized fossil found in the Devonian period showing little morphological changes in 360 million years. Extant lampreys are a small group of 43 species, including anadromous, landlocked, and purely freshwater taxa. Over half the known species are small, non-parasitic, or brook lamprey forms, which never feed during their brief adult lives of six to nine months. The remainder feed as adults in a parasitic manner . The sea lamprey Petromyzon marinus Linnaeus, 1758, is the largest lamprey, reaching a length of 1.2 m and weighing up to 2.3 kg.The word petromyzon is derived from the Greek meaning stone sucker in reference to the characteristic behavior of adults, during the spawning migration, of attaching to stones with their oral disk to rest during the upstream movement and nest building. The word marinus is a reference to the environment from which mature adults migrate from after a 1–2 year period of parasitic feeding in a marine environment, before entering rivers to spawn (...