River lamprey
| River lamprey | ||||||||||||
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River lamprey ( Lampetra fluviatilis ) |
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| Scientific name | ||||||||||||
| Lampetra fluviatilis | ||||||||||||
| ( Linnaeus , 1758) |
The river lamprey ( Lampetra fluviatilis ) is a species of lampreys (Petromyzontidae) and a round mouth (Cyclostomata). It is an anadromous wanderer , which means that the adult river lampreys migrate from the sea to freshwater to spawn . In the sea, the river lampreys feed on fish, to which they attach themselves with their suckers. The muscle meat of the fish is literally shredded with the toothed tongue. A secretion formed by glands in the oral cavity prevents the blood from clotting.
The river lamprey was named fish of the year together with the brook lamprey in Germany in 1988 .
features
Like all other lampreys, the river lamprey has an elongated, eel-like body, the length of which is usually between 30 and 40 centimeters. It has no paired fins and the dorsal fin is divided into two parts: a front and a rear section. The rear part, together with the caudal fin and the anal fin, forms an interrupted fin border that surrounds the rear end of the animal. The color on the flanks and back is dark gray to gray-green, the belly side remains white. The males are slightly smaller than the females.
The seven round gill openings, which together with the real eye and the nostril led to the name "lamprey", are striking. The mouth is transformed into a suction mouth, with which the parasitic living animal to his hosts may lay eyes. In this mouth there are five to nine sharp horn teeth on a horn plate below the mouth opening. There are also other strong teeth above and next to the mouth opening.
distribution
The river lamprey lives in all major rivers in Europe and their estuaries, as well as in the adjacent marine areas. There is no evidence for the eastern Mediterranean and the entire catchment area of the Black Sea, including the Danube, and there is no evidence in the areas of northern Scandinavia or in most of the waters of the Alps .
Way of life
nutrition
As already shown, adult river lampreys live as ectoparasites in sea water, i.e. as external parasites on fish. They attach themselves to their hosts with their suckers and use their horned teeth to grate off tissue from the hosts. The ingested blood does not coagulate due to special enzymes in the saliva of the lampreys.
The larvae, on the other hand, feed as filter feeders on plankton organisms and organic materials that are taken up from fresh water (see below).
Reproduction and development
The young of the river lamprey hatch after about two to three weeks from the eggs in their breeding areas and dig themselves into the muddy ground there. They are called Querder and are anatomically different from adult animals. One of the most important larval features is a gill intestine , which they use to filter food particles out of the water. With the exception of the head, they are stuck in the sediment and ingest plankton and organic material. They also have no eyes at this stage. This larval period lasts between three and four years, during which the animals grow to a length of about 15 centimeters. Then there is a metamorphosis lasting several weeks , in which the gill intestine is transformed into the gills and the other characteristics of the adult animals are formed.
The young river lampreys migrate to the sea with the current and live there until they reach sexual maturity . They are mainly found in the flat coastal area. Unlike the growing sea lampreys, river lampreys are able to rasp off pieces of skin and muscle from their victims. Occasionally they penetrate into the body cavity of their prey fish and kill them. Fish that are attacked by river lampreys include herrings and cod. The sexually mature animals stop feeding in autumn and migrate to the upper reaches of the rivers. It has not yet been clarified whether they will return to their waters of origin. During the return migration, the intestine recedes. After spending their time in the spawning rivers, the river lampreys first go through a winter dormancy, then they mate in the months from February to May.
They then spawn in small groups at water temperatures above 9 ° C. Like the male of the brook lamprey, the river lampreys also make spawning holes. The females suck on each other above these depressions and are embraced by the males with their abdomen. The male presses the eggs out of the female and adds his sperm . A single female lays up to 40,000 eggs within a few days, and the parent animals die after spawning.
People and river lampreys
In the vernacular, river lampreys are also called Bricke , Pricke or Prigge . Lampreys were particularly popular food fish in the Middle Ages ( see also : Lamprete ). However, their populations increasingly declined due to the increasing pollution of the waters and the destruction of suitable spawning grounds, and the larvae in particular are very sensitive to a lack of oxygen . For this reason, this species was included in the EU nature conservation program in accordance with the Habitats Directive . River lampreys are still on the menu in Latvia and Västerbotten , Sweden .
literature
- Roland Gerstmeier and Thomas Romig: The freshwater fish of Europe , Franckh-Kosmos Verlag, Stuttgart 2003, ISBN 3-440-09483-9
Web links
- River lamprey on Fishbase.org (English)
- More information about the river lamprey
- Lampetra fluviatilis in the endangered Red List species the IUCN 2006. Posted by: World Conservation Monitoring Center, 1996. Retrieved on 11 May, 2006.
- Nina Weber: Evolution: Biologists solve lamprey puzzles. In: Spiegel Online , August 7, 2013.
- Walter Salzburger et al .: Strong Genome-Wide Divergence Between Sympatric European River and Brook Lampreys. In: Current Biology 23 (2013), No. 15, doi : 10.1016 / j.cub.2013.06.026 .
- Videos on Lampetra fluviatilis , published by the Institute for Scientific Film . Provided in the AV portal of the technical information library .
Individual evidence
- ↑ Overview "Fish of the Year" in Germany. German Fishing Association, accessed on February 26, 2018 .
- ↑ Gerstmeier and Romig, p. 27.
- ↑ Gerstmeier and Romig, p. 127.
Brook Loach (1984) | Bitterling (1985) | Schneider (1986) | European mud lamb (1987) | Brook lamprey , river lamprey (1988) | Bullhead (1989) | Brown trout (1990) | Minnow (1991) | Atlantic salmon (1992) | Cod (1993) | Nose (1994) | European eel (1995) | Sea trout (1996) | European grayling (1997) | Strömer (1998) | North Sea Bill † (1999) | Atlantic salmon (2000) | European sturgeon (2001) | Burbot (2002) | Barbel (2003) | Allis shad (2004) | Brown Trout (2005) | Bullhead (2006) | Tench (2007) | Bitterling (2008) | European eel (2009) | Crucian carp (2010) | Grayling (2011) | Lamprey (2012) | Trout (2013) | European sturgeon (2014) | Huchen (2015) | Pike (2016) | Flounder (2017) | Three-spined stickleback (2018) | Atlantic salmon (2019)