Stenodus leucichthys is a species of freshwater whitefish in the family Salmonidae. In the strict sense its natural distribution is restricted to the Caspian Sea basin, and it is known as beloribitsa. The beloribitsa is now considered extinct in the wild, but survives in cultured stocks.
Alternatively, the name Stenodus leucichtys has been used in a broader sense, referring to a widespread species composed of two subspecies. In addition to the landlocked subspecies Stenodus leucichthys leucichthys, it comprises the nelma, Stenodus leucichthys nelma (Pallas, 1773) which lives in Eurasian and North American rivers of the Arctic basin. Nelma, also known as the sheefish or inconnu, is currently often considered as a distinct species Stenodus nelma.
At a higher level, the genus Stenodus is not phylogenetically distinct from the broader lake whitefish genus Coregonus, although it is phenotypically characterized by a specialized predator morphology.
Description and status
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.
Beloribitsa 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.
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- Belyaeva, E. S. "Stenodus leucichthys leucichthys". caspianenvironment.org.
- Kottelat, M.; Freyhof, J. (2007). Handbook of European Freshwater Fishes. ISBN 978-2-8399-0298-4.
- Freyhof, J.; and Kottelat, M. (2008). "Stenodus nelma". IUCN Red List of Threatened Species. Version 2011. International Union for Conservation of Nature.
- Froese, Rainer, and Daniel Pauly, eds. (2013). Species of Stenodus in FishBase. February 2013 version.
- Eschmeyer F. Catalog of Fishes (Search: Stenodus (species)) California Academy of Sciences. (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.
- Stenodus leucichthys nelma Illustration of the sister species by N.N. Kondrakov. NOAA Photo Library.