European sturgeon

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European sturgeon
Acipenser sturio.jpg

European sturgeon ( Acipenser sturio )

Systematics
Class : Ray fins (Actinopterygii)
Subclass : Cartilage organoids (chondrostei)
Order : Sturgeon (Acipenseriformes)
Family : Sturgeon (Acipenseridae)
Genre : Acipenser
Type : European sturgeon
Scientific name
Acipenser sturio
Linnaeus , 1758

The European sturgeon ( Acipenser sturio ), not identical to the Baltic sturgeon , is a bony fish from the genus of sturgeon ( Acipenser ). This sturgeon belongs to a very ancient and primeval group within the bony fish, which has a number of primitive features that are missing in younger fish species. These include the heterocercal (i.e., asymmetrical) caudal fin.

The European sturgeon is an anadromous migratory fish and is only very rarely found in the north-east Atlantic today. The last spawning areas of the European sturgeon are in the French Gironde . According to unconfirmed reports, there is still a population of the European sturgeon in the Black Sea that is expected to spawn in the Rioni in Georgia .

Appearance

The European sturgeon grows up to 3.4 meters long and can weigh more than 300 kilograms. Its color varies from brownish-green to blue-black; the sides are lighter. The European sturgeon looks very similar to the Atlantic sturgeon ( Acipenser oxyrinchus ); both types are difficult to distinguish.

The shape of the European sturgeon is shark-shaped, the dorsal fin is shifted far back. The sturgeon has five longitudinal rows of bone shields. On the sides of the body there are 24 to 40 side shields that are very close together and partially overlapping. There are also two rows with ventral shields and one row with humped back shields.

Way of life, endangerment and protection

European sturgeon take their food at the bottom of the water. It mainly consists of various worms (Annelida: Aphrodita , Tubifex , Nephtys , Stylaroides ), molluscs , crabs ( shrimps , beach crabs , amphipods ) as well as mosquito larvae and small fish .

In the 19th century there were still numerous sturgeons in the North Sea and the Baltic Sea , in the Atlantic and the rivers flowing there such as the Rhine , Elbe , Weser and Vistula . Growing environmental destruction, river straightening, shipping and overfishing wiped out the sturgeon everywhere in Germany.

Genetic studies on museum material show that the sturgeon populations in the Baltic Sea and its tributaries were not formed by the European sturgeon, but by the Atlantic sturgeon . The European sturgeon was already in retreat there between 1200 and 800 years ago. The reason for this is assumed to be the drop in water temperatures in the Baltic Sea during the so-called Little Ice Age (16th – 19th centuries); At around 20 ° C, the European sturgeon needs significantly higher temperatures than its cousin from the Atlantic. 13 ° C is enough for the Atlantic sturgeon.

A reintroduction of the European sturgeon on the German North Sea coast and its tributaries is planned for 2009 at the earliest. Measures to reintroduce the Atlantic sturgeon are already being carried out in the Oder and Baltic Seas.

In recent years, exotic sturgeon species and hybridised sturgeon have been sold for breeding in ponds and as ornamental fish. Some of these animals were released or were able to escape. In natural waters they represent a danger for the two very rare native sturgeon species. The reintroduction of native sturgeon is endangered by these abandoned animals.

The European sturgeon was fish of the year 2001 and 2014. In 2001 it was not yet known that the Atlantic sturgeon was native to the eastern parts of Germany in the 19th century.

Classification according to IUCN

On the red list of the IUCN is the kind of European sturgeon with CR ( Critically Endangered, dt. Extinction, extremely high risk of extinction in the wild in the immediate future ) classified in the Habitats Directive ( Fauna-Flora-Habitat Directive , 92/43 / EEC) it is listed as a priority species in Annex II (animal and plant species of Community interest, for the conservation of which special protection areas must be designated) and Annex IV (animal and plant species of Community interest to be strictly protected).

Others

Sturgeon in the coat of arms of Baltiysk

The European sturgeon is the heraldic animal of the city of Baltiysk (Pillau).

literature

  • Roland Gerstmeier, Thomas Romig: The freshwater fish of Europe. Franckh-Kosmos, Stuttgart 2003, ISBN 3-440-09483-9 .

Web links

Commons : Acipenser sturio  - collection of images, videos and audio files

Individual evidence

  1. Reintroduction of the sturgeon ( memento of the original from December 22nd, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Leibniz Institute for Freshwater Ecology and Inland Fisheries (IGB), accessed on December 12, 2015  @1@ 2Template: Webachiv / IABot / www.igb-berlin.de
  2. ^ Acipenser sturio (Atlantic Sturgeon, Baltic Sturgeon, Common Sturgeon). IUCN, accessed December 12, 2015 .