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Revision as of 12:06, 16 February 2013
| Stenodus leucichthys | |
|---|---|
| |
| Conservation status | |
 Extinct in the Wild (IUCN 3.1) | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Salmoniformes |
| Family: | Salmonidae |
| Subfamily: | Coregoninae |
| Genus: | Stenodus |
| Species: | S. leucichthys |
| Binomial name | |
| Stenodus leucichthys (Güldenstädt, 1772) | |
Stenodus leucichthys is a species of freshwater whitefish in the family Salmonidae. It is also known variously by the common names sheefish, inconnu, connie, nelma and beloribitsa. There are two subspecies, sometimes considered distinct species, one of which lives in Eurasian and North American rivers of the Arctic basin, the other in the landlocked Caspian Sea basin. If only one species is recognised, the genus Stenodus would be monotypic.
Description
The fish has a large mouth with a protruding lower jaw and a high and pointed dorsal fin. It is generally silver in color with a green, blue or brown back. The meat is white, flaky and somewhat oily. An adult fish weighs from 14 to 25 kilograms (31 to 55 lb).
The fish eat plankton for their first year of life and then become predators of smaller fish. They live in lakes and rivers and in the brackish water at the outlets of rivers into the ocean, and may migrate 1,500 kilometres (930 mi) to spawn.
Distribution and taxonomy
The species Stenodus leucichthys can be divided into two geographical subspecies. In recent literature these have been considered as separate species, a treatment followed by the IUCN Red List and FishBase, whereas ITIS still makes no distinction.
- Stenodus leucichthys leucichthys (Güldenstädt, 1772), the nominate subspecies, is found only in rivers draining to the Caspian Sea, such as Volga and Ural in particular. This subspecies, known as the beloribitsa, is now extinct in the wild.
- Stenodus leucichthys nelma (Pallas, 1773), known as the nelma, is found in rivers draining to the Arctic basin in North-East Europe, northern Asia and North America.
At a higher level, the genus Stenodus is not phylogenetically distinct from the broader lakefish genus Coregonus, although it is phenotypically charaterized by a specialized predator morphology.
Conservation
Fish of the nominate subspecies used to inhabit particularly the Volga, Ural and Terek rivers, and migrate up to 3,000 kilometres (1,900 mi) upstream from the Caspian to their spawning grounds in the spring. Following the construction of dams and hydropower reservoirs, the migration and natural reproduction has been impeded, and the taxon is now considered as extinct in the wild by the IUCN. The stock however survives in hatcheries and some populations are maintained by stocking.
References
- ^ Belyaeva, E. S. "Stenodus leucichthys leucichthys". caspianenvironment.org.
- ^ Kottelat, M.; Freyhof, J. (2007). Handbook of European Freshwater Fishes. ISBN 978-2-8399-0298-4.
- ^ Template:IUCN
- Template:IUCN
- Froese, Rainer; Pauly, Daniel (eds.). "Species in genus Stenodus". FishBase. February 2013 version.
- "Stenodus leucichthys". Integrated Taxonomic Information System. Retrieved July 15, 2007.
- Eschmeyer F. Catalog of Fishes (Search: Stenodus (species)) California Academy of Scieces. (15 March 2012 version)
- Bernatchez L, Colombani F, Dodson JJ (1991) Phylogenetic relationships among the subfamily Coregoninae as revealed by mitochondrial DNA restriction analysis Journal of Fish Biology 39 (Suppl A):283-290.
- Poursaeid, F. & Falahatkar, B. (2012) Threatened fishes of the world: Stenodus leucichthys leucichthys Güldenstädt, 1772 (Salmonidae). Aqua 18:31-34.
External links
- "Mackenzie River Ecosystem: A Dynamic Delta: Inconnu: The "Unknown" Fish" GreatCanadianRivers.com
- Stenodus leucichthys nelma Illustration by N.N. Kondrakov. NOAA Photo Library.