Diagnostic Description
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英語
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Distinguished by its large mouth, the protruding lower jaw, and the presence of only 13 to 17 gill rakers on the lower limb of the first gill arch (Ref. 27547). Dorsal fin high and pointed; pelvic fins with well developed axillary process (Ref. 27547). Generally silvery, with the back usually rather green, blue or pale brown; silvery white below; dorsal and caudal fins have dusky margins, other fins pale (Ref. 27547).
- Recorder
- Cristina V. Garilao
Life Cycle
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英語
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Upstream migration from wintering areas begins at ice break-up. Early upstream movement may be associated with feeding, but movement soon becomes a definite migration to the spawning area. Spawning begins at dusk, and continuing well into the night. A female accompanied by a male, swims to the surface near the upstream end of the spawning ground. She rapidly moves across the current, extruding her eggs. The male, stays below the female so that as the eggs sink, sperm released, fertilizes the eggs. After completing a spawning pass, the female drifts downstream. She may repeat the spawning act over the downstream portion of the spawning area or may move upstream to the head of the grounds before releasing more eggs. Following spawning, there is a fairly rapid downstream migration to wintering grounds (Ref. 27547). It is not certain if spawning occurs annually or at longer intervals (Ref. 27547). Russian fish appear to spawn only every third or fourth year (Ref. 28219). Spawning frequency at Selawik, Alaska may be every other year (Ref. 27547).
Migration
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英語
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Anadromous. Fish that ascend rivers to spawn, as salmon and hilsa do. Sub-division of diadromous. Migrations should be cyclical and predictable and cover more than 100 km.
Morphology
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英語
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Dorsal spines (total): 0; Dorsal soft rays (total): 11 - 19; Analspines: 0; Analsoft rays: 14 - 19; Vertebrae: 63 - 69
- Recorder
- Cristina V. Garilao
Trophic Strategy
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英語
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Occurs in coastal brackish waters near mouths of rivers, but usually in rivers or some land-locked lakes (Ref. 4779). Nerito-pelagic (Ref. 58426). Adults feed mostly on small fishes; young eat aquatic insect larvae and planktonic crustaceans (Ref. 4779). Adults are found in upper reaches of rivers while young ones are in lower reaches (Ref. 45563).
Biology
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英語
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Nerito-pelagic (Ref. 58426). Occurs in coastal brackish waters near mouths of rivers, but usually in rivers or some land-locked lakes (Ref. 4779). At the sea, it is found throughout basin in pelagic zone with temperatures below 18° C and 20-50 m deep (Ref. 59043). Juveniles and adult overwinter and forage at the sea. Encountered in large lowland rivers during migration (Ref. 59043). Adults feed mostly on small fishes; young eat aquatic insect larvae and planktonic crustaceans (Ref. 4779). During spawning migration, it feeds little if at all (Ref. 27547). Spawns on gravel shallows (Ref. 59043). Flesh is white, sweet and slightly oily (Ref. 27547). Sold fresh or frozen.
Importance
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英語
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fisheries: minor commercial; aquaculture: commercial; gamefish: yes; price category: very high; price reliability: very questionable: based on ex-vessel price for species in this family
Alt, K.T. 1988 Biology and management of inconnu (
Stenodus leucichthys) in Alaska. Finnish Fish. Res. 9:127-132.
Stenodus leucichthys
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英語
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由wikipedia EN提供
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 (literally meaning "the fish that is white" in Russian).[2] The beloribitsa is now considered extinct in the wild, but survives in cultured stocks.[2][3] The nelma (Stenodus nelma), a more widespread species of Eurasian and North America, is sometimes considered its subspecies.[4][5]
Systematics
Alternatively, the name Stenodus leucichtys has been used in a broader sense, referring to a widespread species composed of two subspecies.[3] 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.[2][4][6][5][7]
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.[8]
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.[2][9] The stock however survives in hatcheries and some populations are maintained by stocking.[4]
References
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^ Freyhof, J.; Kottelat, M. (2008). "Stenodus leucichthys". IUCN Red List of Threatened Species. 2008: e.T20745A9229071. doi:10.2305/IUCN.UK.2008.RLTS.T20745A9229071.en. Retrieved 19 November 2021.
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^ a b c d Freyhof, J.; Kottelat, M. (2008). "Stenodus leucichthys". IUCN Red List of Threatened Species. 2008: e.T20745A9229071. doi:10.2305/IUCN.UK.2008.RLTS.T20745A9229071.en.
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^ a b Belyaeva, E. S. "Stenodus leucichthys leucichthys". caspianenvironment.org. Archived from the original on 2013-07-03.
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^ a b c Kottelat, M.; Freyhof, J. (2007). Handbook of European Freshwater Fishes. ISBN 978-2-8399-0298-4.
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^ a b Froese, Rainer and Pauly, Daniel, eds. (2013). Species of Stenodus in FishBase. February 2013 version.
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^ Freyhof, J.; Kottelat, M. (2008). "Stenodus nelma". IUCN Red List of Threatened Species. 2008: e.T135545A4141935. doi:10.2305/IUCN.UK.2008.RLTS.T135545A4141935.en.
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^ Eschmeyer F. Catalog of Fishes (Search: Stenodus (species)) California Academy of Sciences. (15 March 2012 version)
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^ Bernatchez, L.; Colombani, F.; Dodson, J. J. (1991). "Phylogenetic relationships among the subfamily Coregoninae as revealed by mitochondrial DNA restriction analysis" (PDF). Journal of Fish Biology. 39: 283–290. doi:10.1111/J.1095-8649.1991.TB05091.X. Archived (PDF) from the original on 2013-09-27. Retrieved 2012-05-05.
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^ Poursaeid, F.; Falahatkar, B. (2012). "Threatened fishes of the world: Stenodus leucichthys leucichthys Güldenstädt, 1772 (Salmonidae)". Aqua (International Journal of Ichthyology). 18 (1): 31–34. S2CID 86104330.
Stenodus leucichthys: Brief Summary
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英語
)
由wikipedia EN提供
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 (literally meaning "the fish that is white" in Russian). The beloribitsa is now considered extinct in the wild, but survives in cultured stocks. The nelma (Stenodus nelma), a more widespread species of Eurasian and North America, is sometimes considered its subspecies.