October 5, 2010
October 5 - Petromyzon marinus
The sea lamprey, Petromyzon marinus, is a rather gruesome fish - almost right out of a science fiction movie. Hatched in freshwater rivers, the larvae do not possess these fearsome mouths, but are toothless and live a quiet life, buried in the mud where they simply filter feed. Once they grow to a larger size, however, they metamorphosize into the adult, parasitic form, migrate to the sea, and use their suction-cup shaped mouth to latch onto a fish such as a salmon or other bony fish. There, firmly attached, the razor-like teeth and tongue rasp away at the host's flesh and allow the lamprey to feed on blood and bits of tissue. Host fish often die from the excessive blood loss or infections that ensue in the wounds made by these parasites, which can grow up to three feet in length. Native to the coasts of North America and Europe as well as Lake Champlain, which separates New York from Vermont, the construction of the St. Lawrence Seaway may have allowed these parasites to take up firm residence in the Great Lakes, where they now are considered pests due to their feeding on popular game fish such as lake trout and their disruption of the native ecosystem.