Lampreys are scaleless, eel-like, cartilaginous fish that have a round, jawless mouth which suctions onto the flesh of the fish they feed on. There are freshwater and saltwater varieties, and they are considered a major pest in the Great Lakes of North American, where they are an invasive species. Not valued as food in America, they are prized as a delicacy in Europe and some parts of Asia and have a taste described as "meaty."
Lampreys, considered by some to not be fish at all, are interesting in the differences they exhibit compared to bony fish. Unlike bony fish, their fins are not paired, and they have one nostril and a third pineal eye on top of their head. They have 7 gills on each side. They have no vertebral column, and their body is supported by a notochord. Their round mouth has teeth made from keratin, and they have teeth on their tongues. To eat, they suction onto the side of a fish, and scrape a hole in the fish with their tongue. They produce an anticoagulant to keep the blood flowing, and they hitch a ride with their host until the fish dies or they let go. They do not need to pass water through their mouth to ventilate their gills. They are from 5 to 40 inches in length (13 to 100 centimeters).
Sea lampreys were introduced to the Great Lakes from the Atlantic Ocean when canals were built in the 1800s to bypass Niagra Falls. They spread to all 5 lakes, and having no natural predators, devastated native fish populations, such as lake trout, rainbow trout, brown trout, walleye, salmon and catfish. The Great Lakes Fishery Commission undertook to control lamprey populations, and used a combination of techniques, including lampricide (called TFM, a poison used to kill lamprey larvae), migration barriers, sterile male release, and trapping. They achieved a 90% reduction in lamprey numbers, and lampreys are now considered under control, but not eliminated, in the Great Lakes.
Lampreys are Agnathans, a superclass of jawless fish, phylum Chordata, subphylum Vertebrata. Once system of taxonomy (Fisher 1994) classifies them as the lone members of the class Cephalaspidomorphi, order Petromyzontiformes, family Petromyzontidae.
|
Picture of the mouth parts of the lamprey, of the class Agnatha, or jawless fishes, among the most primative of all bony fish, family Petromyzontidae
Picture #: 070068 |
Stock photo of basking shark, Cetorhinus maximus, with parasitic lampreys, Petromyzon marinus, Bay of Fundy, Canada, North Atlantic Ocean
Picture #: 006587 |
Image of a green, great or spotted, sea lamprey, Petromyzon marinus, Bay of Fundy, Canada, Atlantic Ocean
Picture #: 011213 |
Photo of a lamprey, Petromyzontidae Ichthyomyzon unicuspis, feeding on a fish
Picture #: 095929 |
