Sea lamprey ( Petromyzon marinus )
|Scientific name of the genus|
|Linnaeus , 1758|
|Scientific name of the species|
Sea lamprey have an eel-like body shape with no pectoral or ventral fins and a round mouth without a jaw. Adult, sexually mature animals usually reach a body length of 70 to 90 centimeters, occasionally up to 1.2 meters. Depending on their origin, sea lamprey differ in color. Most have a light gray to greenish base color and are darkly spotted or marbled on the top. The head has a skull and has a pair of eyes above the suction mouth, which are followed by seven rounded gill openings on each side. In contrast to other types of lamprey , the mouth disk is wider than the body. The edge of the suction opening looks frayed and has sharp horn teeth.
Way of life
The sea lamprey is an anadromous wanderer living near the coast who ascends into rivers to reproduce. Its European distribution area extends from Scandinavia over the North and Baltic Seas to the western Mediterranean. In addition, the species is found on the east coast of North America and also lives - after the opening of the Niagara Falls immediate Wellandkanals - now also in the Great Lakes of North America above the Lake Ontario .
Sea lamprey migrate upstream to spawn , but not as high as the river lamprey . They spawn in small groups in gravelly places. Here the eggs are laid in pairs in specially designed nest pits. It has been proven that they migrate up to 850 kilometers to their spawning grounds: Among other things, they spawn in the Rhine near Basel. After reproduction, the parent animals die. The larvae that hatch after a few weeks, also known as Querder , remain in the sediment of freshwater for about six to eight years. Only after they have been transformed into an adult animal migrate into the sea. There they reach sexual maturity after another three to four years. In the sea, the lampreys feed by attaching themselves to fish such as cod, mackerel, salmon and herring with their suction pads, parasitizing their skin and muscle tissue and sucking blood. When they return to fresh water, the intestines regress.
The sea lamprey is one of the most important lampreys as a food fish .
In the Great Lakes of North America, sea lamprey spread invasively in the 20th century, shifting the ecological balance and - since they threaten the stocks of fish species that are important for the fishing industry - in some cases intensively fought, also with an anthelmintic such as niclosamide as a lampreticide.
As the European habitats of this migratory fish species are threatened, the EU has included it in the Annex to the Habitats Directive .
In the genome of sea lampreys were various so-called DNA transposons demonstrated that very similar in numerous unspecified related species of bony fish have been found. Apparently, these mobile DNA sequences - transposase- encoding Tc1 elements - have been exchanged between different species of vertebrates through a horizontal gene transfer , with the lamprey's parasite-host relationship probably playing a major role.
- S. Silva, R. Vieira-Lanero, S. Barca, F. Cobo: Densities and biomass of larval Sea Lamprey populations ( Petromyzon marinus Linnaeus, 1758) in North West Spain and data comparisons with other European regions. In: Marine and Freshwater Research. March 2016.
- see Petromyzon marinus as a non-indigenous aquatic species of the Great Lakes, GLANSIS data sheet from NOAA .
- R. Gerst Meier, T. Romig: The freshwater fish in Europe. Franckh-Kosmos Verlag, Stuttgart 2003, p. 125.
- S. Silva, MJ Araújo, M. Bao, G. Mucientes, F. Cobo: The haematophagous feeding stage of anadromous populations of sea lamprey Petromyzon marinus: low host selectivity and wide range of habitats. In: Hydrobiologia. Volume 734 (1), 2014, pp. 187-199.
- R. Scholefield, R. Bergstedt, T. Bills: Relation of concentration and exposure time to the efficacy of niclosamide against larval sea lampreys (Petromyzon marinus). In: Journal of Great Lakes Research. Volume 29 (1). USGS 2003, pp. 493-499.
- Shigehiro Kuraku, Huan Qiu, Axel Meyer: Horizontal Transfers of Tc1 Elements between Teleost Fishes and Their Vertebrate Parasites, Lampreys. In: Genome Biology and Evolution. Volume 4 (9), August 2012, pp. 929-936 ( PDF ).
- Roland Gerstmeier and Thomas Romig: The freshwater fish of Europe , Franckh-Kosmos Verlag, Stuttgart 2003, ISBN 3-440-09483-9
- Jeramiah J. Smith et al .: Sequencing of the sea lamprey (Petromyzon marinus) genome provides insights into vertebrate evolution. Nature Genetics (2013), doi: 10.1038 / ng.2568