Sea lamprey

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Petromyzon marinus

Sea lampreys on a lake trout

Kingdom:	Animalia
Phylum:	Chordata
Class:	Cephalaspidomorphi
Order:	Petromyzontiformes
Family:	Petromyzontidae
Genus:	Petromyzon
Species:	P. marinus

Binomial name

Petromyzon marinus
(Linnaeus, 1758)

The sea lamprey's oval mouth contains concentric rings of sharp teeth, with a bony, rasping tongue used to bore into its host. Source: US EPA Great Lakes National Program Office.

The sea lamprey (Petromyzon marinus) is a parasitic lamprey (a kind of jawless fish) found on the Atlantic coasts of Europe and North America, in the western Mediterranean Sea, and in the Great Lakes. It is brown or gray on its back and white or gray on the underside and can grow to be up to 90 cm (35.5 in) long. 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 teeth. Secretions in the lamprey's mouth prevent the victim's blood from clotting. Victims typically die from blood loss or infection.

The life cycle of sea lampreys is anadromous, like that of salmon.The young are born in inland rivers, live in the ocean as adults, and return to the rivers to breed. Young emerge from the egg as larvae, blind and toothless, and live that way for 3 to 17 years, buried in mud and filter-feeding. Once they have grown to a certain length, they metamorphosize into their parasitic form, after which they migrate to the sea. After about 12 to 20 months, they metamorphosize into their adult form and return to the rivers and streams and spawn, after which they die.

Sea lampreys are considered a pest invasive species in the Great Lakes region. The species is native to the inland Finger Lakes and Lake Champlain in New York and Vermont. It is not clear whether it is native to Lake Ontario, where it was first noticed in the 1830s, or whether it was introduced through the Erie Canal, which opened in 1825.^[1] It is thought that improvements to the Welland Canal in 1919 allowed its spread from Lake Ontario to Lake Erie, and while it was never abundant in either lake, it soon spread to Lake Michigan, Lake Huron, and Lake Superior, where it decimated indigenous fish population in the 1930s and 1940s. They have created a problem with their aggressive parasitism on key predator species and game fish, such as lake trout, lake whitefish, chub, and lake herring. Elimination of these predators allowed the alewife, another invasive species, to explode in population, having adverse effects on many native fish species. Control efforts, including electric current, chemical lampricides, and barriers, have met with varied success. The control programs are carried out under the Great Lakes Fisheries Commission, a joint Canada-US body, specifically by the agents of the GLFC, Fisheries and Oceans Canada, and the United States Fish and Wildlife Service.

Genetic researchers have begun mapping the sea lamprey's genome in the hope of finding out more about evolution; scientists trying to eliminate the Great Lakes problem are co-ordinating with these genetic scientists, hoping to find out more about its immune system and fitting it into its place in the phylogenetic tree. Several scientists in this field work directly for Fisheries and Oceans Canada or the United States Fish and Wildlife Service. Researchers from Michigan State University have teamed up with others from the Universities of Minnesota, Guelph, Wisconsin, as well as many others in a massive research effort into newly synthesized pheromones. These are believed to have independent influences on the sea lamprey behavior. One pheromone serves a migratory function in that odor emitted from larva are thought to lure maturing adults into streams with suitable spawning habitat; the other, a sex pheromone, is emitted from males and is capable of luring females long distances to very specific locations - even in complete darkness and even though many lamprey at this stage in their life have strongly degraded eyesight. These two pheromones are actually both several different compounds that are thought to elicit different behaviors that collectively influence the lamprey to exhibit migratory behaviors or spawning behaviors. Effort is being made to characterize the function of each pheromone, each part of each pheromone, and if they can be used in a targeted effort at environmentally friendly lamprey control. It is the hope of the Great Lakes Fisheries Commission that at least some of this brilliant work into sea lamprey genetics as well as pheromones will pan out into a successful, effective management technique that could one day drastically reduce the need for TFM treatments of spawning grounds. Despite millions put into research however, the most effective control measures are still being undertaken by control agents of State and Federal Agencies but involve the somewhat publicly unacceptable dumping of TFM into our nation’s rivers.

One of the leading facilities promoting research into sea lamprey control is the Hammond Bay Biological Station (HBBS). The station is located on the southeastern side of Hammond Bay on Lake Huron. It is in between Rogers City, Michigan and Cheboygan, Michigan just off of highway 23. The station head, Roger Bergstedt, has lead the crusade against sea lamprey for many years. He is one of the main collaborators on any research involving sea lamprey in the area due to the tremendous facilities at his disposal and his many years of experience. Graduate researchers, professors, and their armies of (usually) student technicians have come and gone over the years taking up temporary residence around Hammond Bay to conduct research. So many have rotated rapidly in and out of working at the station while Roger remains directing the efforts, that it is often said that researchers can get caught in the "Roger Vortex". People are drawn in temporarily, and then leave almost as suddenly as they came. Despite this high turnover rate in rotation, their is always someone available to occupy the new vacancy. The station also employs several promising local youths every year who plan to or are currently enrolled in a scientific degree program. The area is sparsely populated but Roger and the staffs at HBBS continue to make an effort to help out those around them offering generous wages while also serving as inspiration for many considering fields of science. Part of this effort includes guided tours, which are nearly always conducted personally by Roger. Roger is known for is easy going attitude when giving tours as well as the incredible depth at which he can explain some aspects of lamprey biology despite the audience. In the summer when lamprey action is at its heights, HBBS has seen groups of people to the tone of 50+ visit for the educational experience as well as (if they are lucky) the experience of seeing Roger allow a lamprey to suction onto his face. Large groups of nationally renown media sources as well documentary film crews from around the world have visited HBBS in trying to learn about the fantastic things being done there while also exposing the public to something interesting that they wouldn't normally see. Lampreys are hated by many due to their snake like appearance, slime coats, and mouths full of sharp looking teeth. Despite this fact, lampreys continue to draw people by the thousands every summer simply because they are curious about something that is arguably one of the more 'alien' looking creatures on the planet.

In 1996, the University of Minnesota - Duluth decided to try a lamprey taste test. Many dishes were prepared by chef Bob Bennet, of Bennets Bar & Grill in Duluth, Minnesota. Among the dishes were combinations like Lamprey Stew & Garlic Mashed Potatoes, and Arroz de Lampreia (lamprey rice). Doug Jensen, aquatic invasive species coordinator for UMN Sea Grant, was among the testers. He said it tasted actually pretty good. It is not recommended however to eat great lakes sea lamprey as they have taken up a super predator position in the ecosystem. Top predators, those that are usually the ones eating others rather than being eaten (such as lake trout) are known to be subject to Bioaccumulation. This, over time, slowly increases the concentration of lipid soluble, man-made, sometimes harmful substances to reach levels that would render the fish un-healthy and perhaps unsafe for human consumption. Sea lamprey have taken up the new top predator level in that they primarily feed on these other large predatory fish. While they are not a traditional predator (usually thought of as a parasite), in the great lakes they grow large enough where their feeding attacks on native fish are often deadly. Oceanic sea lamprey have fish available to them that can get much larger than great lakes fish and can subsequently survive attacks. With this new role in the ecosystem, they are subject to vast contamination when feeding on these already highly contaminated fish. Markets have been attempted in some European countries that consider sea lamprey a delicacy but did not take due to the high level of unsafe contaminate. If one were to cook sea lamprey, it may be best to use feeding techniques that minimize the intake of harmful passengers in the fats. The University of Minnesota's attempt at a taste test for sea lamprey was consequently not very well thought out. As a result of this blunder, it is well known that state agencies in Minnesota actively recruit students and scientists to work for them who are not graduates of UMN and therefore are likely not to have been taught by the same people who may promote potentially toxic lamprey consumption.^[2]