Wolffish (fish)
| Wolffish | ||||||||||||
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Wolffish |
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| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Cobitis taenia | ||||||||||||
| Linnaeus , 1758 |
The wolffish ( Cobitis taenia , also called thorn goby ) is a freshwater fish widespread in Europe and Asia . It is protected according to Annex II of the Habitats Directive .
features
Wolffish reach a length of 8 to 10 cm, females occasionally up to 12 cm. The weight is 20 to 60 g. The back has a yellow-brown color interrupted by many small dark spots. On the ventral side, the scales are pale yellow to orange in color. The comb on the back has several rows of black-gray spots. The body is elongated. The loach has 6 barbels on its mouth . Under each eye there is a two-pointed, actively moving thorn with which it can inflict painful stitches.
distribution
The loach is common in Siberia and all of Europe, with the exception of Ireland , Scotland , Wales and northern Scandinavia . There are regionally limited subspecies.
habitat
Slow flowing and stagnant waters with clear, oxygen-rich water are preferred. Loewe occur there in flat and sandy or stony places, often in large numbers.
Way of life
Loewas dig into the ground, with only the head and tail sticking out. Foraging takes place at night. For this purpose, the sand is chewed through in search of small animals and organic material. The sand is expelled again through the gills. For the fish to survive, it is important that the subsoil is regularly rearranged.
Loewe have the option of accessory intestinal breathing . Air swallowed on the surface of the water is deprived of oxygen in the rectum. The used air is excreted through the anus. Bridging times of low oxygen is made easier for the loach.
The loach can reach an age of 3 to 5 years. The maximum in captivity is given as 10 years.
Reproduction
The spawning season is from April to June. The females lay between 300 and 1500 eggs near the ground, on stones, roots or plants in several portions and then inseminated by the males. The larvae hatch after 4 to 6 days. Within the species group, some female wolffish can reproduce asexually by means of gynogenesis : These females must be triploid , their triploid egg cells then divide into new fish after contact with the male sex cells without fertilization. Mother and daughter then genetically resemble each other like twins. But only “hybrid females” can do that, which are the result of crossing two species (cf. the mule ). The pure species occurs in the Weser system and hybrids in the Rhine system .
Legal protection status
The loach is listed by the European Union in Annex II of the Habitats Directive and is therefore considered a type of community interest, for whose preservation special protected areas must be designated by the member states. Only the Finnish populations are excluded.
literature
- Lars Tatenhorst, Norbert Kaschek, Elisabeth I. Meyer: The loach . Aspects of the ecology of a threatened species. Schüling-Verlag, Münster 2002, ISBN 3-934849-24-5 .
Web links
- Wolffish (fish) on Fishbase.org (English)
- Information on the gynogenesis of female wolffish ( Memento from February 22, 2006 in the Internet Archive )
- Cobitis taenia inthe IUCN 2013 Red List of Threatened Species . Posted by: Freyhof, J., 2010. Retrieved September 21, 2013.
Individual evidence
- ↑ Freyhof, J., 1999. A confusing group of species: wolffish. DATZ 52 (11): 14-18.
- ↑ Loach (Cobitis taenia). In: deutschlands-natur.de. manderbachmedia, accessed on February 26, 2019 .