The sea lamprey (Petromyzon marinus) is a parasitic lamprey native to the Northern Hemisphere. It is sometimes referred to as the "vampire fish". Description The sea lamprey has an eel-like body without paired fins. Its mouth is jawless, round and sucker-like, and as wide or wider than the head; sharp teeth are arranged in many concentric circular rows. There are seven branchial or gill-like openings behind the eye. Sea lampreys are olive or brown-yellow on the dorsal and lateral part of the body, with some black marblings, with lighter coloration on the belly. Adults can reach a length of up to and a body weight up to . Etymology The etymology of the genus name Petromyzon is from petro- "stone" and myzon "sucking"; marinus is Latin for "of the sea". Distribution and habitat The species is found in the northern and western Atlantic Ocean along the shores of Europe and North America, in the western Mediterranean Sea, the Black Sea, and as an invasive species in the shores of the Great Lakes. They have been found at depths up to 4000 meters and can tolerate temperatures of . In North America, they are native to the Connecticut River basin in the United States. The largest European populations of sea lampreys are located throughout the southwestern areas of Europe (north-central Portugal, north-northwest of Spain, and west–southwest of France). These countries also support the main fisheries of the species. Ecology Sea lampreys are anadromous; from their lake or sea habitats, they migrate up rivers to spawn. Females deposit a large number of eggs in nests made by males in the substrate of streams with moderately strong current. Spawning is followed by the death of the adults. Larvae burrow in the sand and silt bottom in quiet water downstream from spawning areas and filter-feed on plankton and detritus. After several years in freshwater habitats, the larvae undergo a metamorphosis that allows young, post-metamorphic lampreys to migrate to the sea or lakes, and start the adult hematophagous method of feeding. Some individuals start hematophagous feeding in the river before migrating to the sea, where sea lampreys prey on a wide variety of fish. The lamprey uses its suction cup-like mouth to attach itself to the skin of a fish and rasps away tissue with its sharp, probing tongue and keratinized teeth. A fluid produced in the lamprey's mouth, called lamphredin, prevents the victim's blood