Biology
provided by Arkive
Commonly found in coastal waters, the star sturgeon spends the day close to the seabed, where its downward-facing mouth helps it to feed on bottom-dwelling organisms, such as worms, molluscs and small fish (2) (4). At night, the star sturgeon becomes more active, rising up to the water surface to find other sources of prey (4).
In order to reproduce, the star sturgeon must undergo a migration from the sea into a freshwater river, swimming upstream to the spawning ground. Interestingly, there are two separate “races” of star sturgeon, which display different spawning behaviours. One race migrates and spawns during spring and summer, while the other migrates in the winter, over-winters in the river and spawns in the following spring (2). A single female produces a vast amount of eggs, in the order of hundreds of thousands, which stick to river vegetation and stones (6).
Generally, it is only the juvenile star sturgeons that are threatened by predation, as the large size and armour of the adults helps to deter predators (2) (6). Nevertheless, on occasion, the parasitic, eel-like lamprey has been known to cause fatal injuries to adult star sturgeons (6).
Conservation
provided by Arkive
In 1998, the star sturgeon was listed by the Convention on International Trade in Endangered Species (CITES), meaning that all international trade in this species is controlled by maximum export quotas and trade permits (2) (3). The countries which are party to the CITES agreement must agree on sustainable catch and export quotas based on scientific surveys, and must adopt regional conservation strategies and attempt to combat illegal fishing. The strict enforcement of these regulations meant that in 2006, caviar export was banned for all of the countries bordering the Caspian Sea, since the countries failed to provide sufficient information about the sustainability of their catch. This promoted an agreement between the countries to reduce their star sturgeon caviar export quotas in 2007 by over 25 percent (8). The countries bordering the Black Sea have adopted an even stricter policy regarding their sturgeon stocks, maintaining a zero quota policy, which has continued into 2008 (9). Whether these reduced quotas will prove sufficient to allow the star sturgeon's population to recover remains to be seen.
Due to limited natural spawning grounds, a high proportion of star sturgeon stock in the Caspian and Azov seas is maintained by farm-grown fish released into the wild. Unfortunately, however, poaching has reduced the numbers of adult star sturgeons so dramatically that hatcheries are struggling to obtain enough breeding fish to conduct artificial propagation (2). In an attempt to control the illegal trade in this species, in 2007 a world database for caviar trade was set up to monitor the origin of exported caviar and track shipments around the world (10).
Description
provided by Arkive
Belonging to an ancient group of fish, the prehistoric-looking star sturgeon is notable for being one of the three main caviar producing sturgeon species (2). Reaching over two metres in length, the star sturgeon's elongated body is armoured with rows of hard, spiky, white nodules, which brightly contrast with the blackish-grey upperparts. Like other sturgeons, the star sturgeon's mouth is found on the underside of its head, with a cluster of short barbells located between the mouth and the tip of its long, pointed snout. The tail fin is uneven, with a small, short lower lobe and a much larger upper lobe extending upwards and away from the body (4).
Habitat
provided by Arkive
The star sturgeon can tolerate a range of habitats, from the salty waters of the Aegean and Adriatic Seas, to the freshwater conditions of the Danube (2) (5).
Range
provided by Arkive
The star sturgeon inhabits the Black, Caspian and Azov Seas, and associated rivers and waterways such as the Danube (1) (2). Individuals have also been found in the Adriatic Sea, off the west coast of Italy, and in the Aegean Sea, around the coasts of Greece and Turkey (5)
Status
provided by Arkive
Classified as Endangered (EN) on the IUCN Red List (1) and listed on Appendix II of CITES (3).
Threats
provided by Arkive
The major threat to the star sturgeon's survival is overfishing for its meat and, more significantly for caviar, sold under the name “sevruga”. This is produced from the sturgeon's unfertilised eggs and is almost always extracted by killing the female. The caviar industry is currently in crisis, as the dwindling stocks of the star sturgeon, and the other major caviar producing species, can no longer provide sufficient caviar to meet the huge worldwide demand (2). Despite attempts to manage star sturgeon stocks, illegal fishing and black market trade in caviar are threatening to drive this already endangered species to extinction (2) (7).
The threat of overexploitation for the caviar trade is also exacerbated by a reduction in the star sturgeon's natural spawning grounds due to the construction of hydroelectric power stations and reservoirs, and also by the high levels of pollution found throughout its range (2).
Benefits
provided by FAO species catalogs
Commercial. Fish catch limited.
Brief Summary
provided by FAO species catalogs
During the daytime they are often encountered in the upper layer, while at nigth, they are generally found at the bottom.The starry sturgeon inhabits the coastal sea waters (at depths from 100 to 300 m in the Caspian Sea) over clayey or sandy and clayey sediments, and the lowland section of rivers.Feeding habits vary with size, season and specific features of the water bodies (rivers or sea). The younger individuals feed primarily on crustaceans, while fishes (Gobiidae, Caspialosa, and Clupeonella) become more important in the diet as the grey older. Also molluscs, Polychaeta and other invertebrates. Sexual maturity is reached by males at an age of five or six years. Females mature with an average age of 9.7 years and rarely spawn more than three times in their lives. Enters rivers from April to June with a peak period when the water temperature reaches 10º to 15ºC. Eggs laid on beds of scattered stones, pebbles, gravel and sand. The juveniles stay near the mouth of rivers. Its population is supported by artificial propagation. Spawn from May to September at a water temperature of 12º to 29ºC.
Size
provided by FAO species catalogs
Maximum length of 218 cm (TL) and a maximum weight of 54 kg. They usually range from 100 to 120 cm and 6 to 8 kg.
Distribution
provided by FAO species catalogs
Caspian, Azov, Black, and Aegean Seas, from which it migates into the rivers (Shubina et al., 1989).
Diagnostic Description
provided by FAO species catalogs
Spiracle present. Snout greatly elongated and sword-shaped, usually more than 60 % of the head length. Gill membranes joined to isthmus. Mouth transverse and lower lip with a split in the middle. The barbels are short and no fimbriate, not reaching the mouth but nearer to it than to tip of snout. D: 40-54; A: 22-35 fin rays. 9-16 dorsal scutes; 26-43 lateral scutes; 9-14 ventral scutes. The dorsal scutes have radial stripes and strongly developed spines with the tips directed caudal. Between the rows of scutes, the body is covered by star plates. The body colouration is blackish-brown dorsally and laterally. The belly is light, and the ventral scutes are dirty white coloured.
- Banarescu, P. - 1964. Pisces-Osteichthyes. Fauna Republicii Populare Romine. 13. Ed: Academiei Republicii Populare Romine, Bucaresti.
- Bauchot, M.-L - 1987. Poissons osseux In W. Fischer, M.L. Bauchot and M. Schneider (eds.). Fiches FAO d'identification pour les besoins de la pêche. (rev. 1). Méditerranée et mer Noire. Zone de pêche 37. Vol. II. Commission des Communautés Européennes and FAO, Rome. p. 891-1421.
- Berg, L.S - 1962. Freshwater fishes of the U.S.S.R. and adjacent countries. Israel Program for Scientific Translations Ltd, Jerusalem. Volume 1, 4th edition. Russian version published 1948.
- Hilton-Taylor, C. - 2000. 2000 IUCN red list of threatened species. IUCN, Gland, Switzerland and ambridge, UK. xviii + 61 p. with 1 CD-ROM.
- Kottelat, M. - 1997. European freshwater fishes. Biologia. 52, Suppl. 5:1-271.
- Shubina, T.M., A.A. Popova & V.P. Vasilev - 1989. Acipenser stellatus Pallas,1771. In The Freshwater Fishes of Europe, Vol.1, Part II: General Introduction to Fishes. Acipenseriformes. 394-442. (Ed. J. Holcík) AULA-Verlag Wiesbaden.
- Svetovidov, A.N. - 1984. Acipenseridae In P.J.P. Whitehead, M.-L. Bauchot, J.-C. Hureau, J. Nielsen and E. Tortonese (eds.) Fishes of the north-eastern Atlantic and Mediterranean. UNESCO, Paris. vol. 1. :220-225.
Trophic Strategy
provided by Fishbase
At bottom during the day, rising to surface to feed at night. Long migrations in sea.
Morphology
provided by Fishbase
Dorsal spines (total): 0; Dorsal soft rays (total): 40 - 46; Analsoft rays: 24 - 29
Migration
provided by Fishbase
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.
Diagnostic Description
provided by Fishbase
Snout long, pointed at tip. Lower lip not continuous, interrupted at center. Barbels short not reaching mouth but nearer to it than to tip of snout. Five rows of scutes, dorsal 11-14, lateral 30-36 on each side, ventral 10-11 on each side, with small bony stellate plates and smaller grains between main scute rows. Back dark grey to almost black, flanks lighter, belly white.
Biology
provided by Fishbase
At the sea, it occurs in coastal and estuarine zones and forages on the bottom mostly on clayey sand and intensively in the middle and upper water layers (Ref. 59043). Found mainly near shore over sand and mud, stays at the bottom during the day and rises to the surface to feed at night. Feeds mainly on fish, also mollusks, crustaceans and worms (Ref. 3193). Spawns in strong-current habitats in main course of large and deep rivers, on stone or gravel bottom. Spawning also takes place on flooded river banks and if gravel bottom is not available, on sand or sandy clay. Juveniles stay in shallow riverine habitats during first summer (Ref. 59043). One of the three most important species for caviar; also utilized fresh and frozen; eaten pan-fried, broiled and baked (Ref. 9988). Overfishing at the sea for meat and caviar will soon cause extinction of the natural populations and their survival can only depend on stocking (Ref. 59043).
Importance
provided by Fishbase
fisheries: commercial; aquaculture: commercial; aquarium: public aquariums
Starry sturgeon
provided by wikipedia EN
The starry sturgeon (Acipenser stellatus) also known as stellate sturgeon or sevruga (Drakul, Persian: اوزون برون, and Turkish: Uzun Burun, lit. 'long nosed'), is a species of sturgeon. It is native to the Black, Azov, Caspian and Aegean sea basins, but it has been extirpated from the last and it is predicted that the remaining natural population will follow soon due to overfishing.[1]
The starry sturgeon is an anadromous species, which migrates up rivers to spawn.[6]
It is considered critically endangered by the IUCN and international trade in this species (including its caviar) is restricted by CITES.[1]
Description
The starry sturgeon reaches about 220 cm (7.2 ft) in length and weighs up to 80 kg (180 lb).[6] It is a slim-bodied fish easily distinguished from other sturgeons by its long, thin and straight snout. A row of five small barbels lies closer to the mouth than to the tip of the snout. The scales on the lateral line number between thirty and forty and these features distinguish this fish from the Russian sturgeon (Acipenser gueldenstaedtii). Its general colouring is dark greyish-green or brown with a pale underside. The scales on the lateral line are pale.[7] The maximum reported age for this species is 27 years.[6]
Biology
The starry sturgeon is a harmless species that feeds on fish, worms, crustaceans and mollusks.[6] It lies on the bottom during the day and feeds mostly at night. This fish is anadromous and moves upriver into shallow waters to spawn.[7]
Uses
The starry sturgeon is an important commercial species of fish. It is one of the three most important species for caviar, see Sevruga caviar, along with the Beluga sturgeon and the Ossetra sturgeon. Its flesh is considered an expensive delicacy in the Caspian region. It is used to make kabaabs, or is consumed pan fried, broiled, or smoked. There have been several attempts in Russia, Iran, Italy, and the United States to adapt this species for aquaculture, with varying degrees of success.
The resilience of this species is low. The minimum population doubling time is 4.5 – 14 years.
See also
References
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Starry sturgeon: Brief Summary
provided by wikipedia EN
The starry sturgeon (Acipenser stellatus) also known as stellate sturgeon or sevruga (Drakul, Persian: اوزون برون, and Turkish: Uzun Burun, lit. 'long nosed'), is a species of sturgeon. It is native to the Black, Azov, Caspian and Aegean sea basins, but it has been extirpated from the last and it is predicted that the remaining natural population will follow soon due to overfishing.
The starry sturgeon is an anadromous species, which migrates up rivers to spawn.
It is considered critically endangered by the IUCN and international trade in this species (including its caviar) is restricted by CITES.
- license
- cc-by-sa-3.0
- copyright
- Wikipedia authors and editors
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