Deep-sea char
| Deep-sea char | ||||||||||||
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| Salvelinus profundus | ||||||||||||
| Schillinger , 1901 |
The deep-sea char ( Salvelinus profundus ), sometimes also known as Lake Constance deep char , is a freshwater fish species from the genus of char ( Salvelinus ) within the salmon fish family . It is endemic to Lake Constance .
features
The deep-sea char reaches a standard length of 240 mm. It has 19 to 27 gill spines . The height at the beginning of the anus is 15 to 16 percent of the standard length. The eye diameter is 1.3 to 1.5 times the distance between the eye sockets and makes up 19 to 21 percent of the head length. The snout is blunt, the mouth is below. The lower jaw is enclosed by the upper jaw. The flanks are yellowish to silvery, sometimes with pale light spots. The belly is sometimes reddish. The brownish to reddish brown fins lack the white edges of the other char species. The pectoral fin does not reach the anus.
Way of life
The deep-sea char occurs at a depth of 80 meters and feeds on vortex worms , copepods and pea clams . The spawning season is between July and February. The eggs are laid on the gravel bottom at a depth of 60 to 80 meters. Caught deep-sea char often had inflated bellies because the pressure difference between the great water depth and the water surface is so great that the air in the fish expands.
status
The deep lake trout was in 2008 by the IUCN for "Extinct" ( Extinct explained). Until the 1960s, it was a frequently caught species in the commercial fishing of Lake Constance. When the eutrophication of Lake Constance reached its peak in 1979, it prevented the deep-sea char from reproducing. After several searches were unsuccessful over a period of ten years, the deep-sea char was considered extinct. Today the name deep-sea char is sometimes used for the form Salvelinus umbla , which also occurs in Lake Constance .
As part of the “Projet Lac” project, which was carried out between 2010 and 2015, Eawag found several specimens of the deep-sea char in a targeted search. In the future it will be investigated how big the population is.
literature
- Jörg Freyhof , Maurice Kottelat : Salvelinus evasus sp. n., a charr from deep waters of Lake Ammersee, southern Germany (Teleostei: Salmonidae), with comments on two extinct species. In: Revue Suisse de Zoologie. Vol. 112, No. 1, 2005, ISSN 0035-418X , pp. 253-269, online (PDF; 4.8 MB) .
- Maurice Kottelat, Jörg Freyhof: Handbook of European Freshwater Fishes. Publications Kottelat, Cornol 2007, ISBN 978-2-8399-0298-4 , p. 455.
Individual evidence
- ^ Salvelinus profundus in the Red List of Threatened Species of the IUCN 2015.4. Posted by: Freyhof, J. & Kottelat, M., 2008. Accessed March 1, 2016.
- ↑ Eawag: Surprises from the depths of the Swiss lakes , September 6, 2016.