| ||Acipenser pygmaeus Pallas, 1814:102.|
| ||Acipenser marsigli Brandt, 1833:352.|
| ||Acipenser gmelini Fitzinger and Haekel, 1836:276.|
| ||Acipenser primigenius Chalikov, 1944:47.|
| ||Acipenser ruzskyi Ioganzen, 1946:173.|
| ||Acipenser ruthenus brevirostris Antipa, 1909:250.|
| ||Acipenser ruthenus obtusirostris Brusina, 1902|
|En - Sterlet sturgeon, Fr - Sterlet, Sp - Esterlete.|
3Alpha Code: APR Taxonomic Code: 1170100104|
|Scientific Name with Original Description|
|Acipenser ruthenus Linnaeus, 1758. Syst. Nat., ed X: 237 Russia.|
|Snout and caudal peduncle subconical. Snout length and form highly variable. Generally, sterlets with pointed snouts tend to be young specimens, and the average age of those with blunt snouts is greater.
Spiracle present. Gill membranes joined to isthmus. Mouth transverse and lower lip with a split in the middle. Barbels fimbriate.
11-27 gill rakers.
11-18 dorsal scutes. 56-71 lateral scutes. 10-20 ventral scutes.
Numerous bony plates between the rows of scutes.
Colouration varies greatly. Back usually dark greyish-brown. Belly yellowish white. The scutes are dirty white and the fins, grey.
|The sterlet is a Eurasian species inhabiting rivers flowing into the Caspian, Black, Azov, Baltic, White, Barents, and Kara Seas (Sokolov & Vasilev, 1989).|
|Habitat and Biology|
|The sterlet is a potamal freshwater fish that seldom occur in large lakes. It inhabits the lowland and foothill zones of the rivers and usually stays in the current in deep depression in the riverbed. Small specimens are often encountered in sandy shallows. The two kinds of spawning sites are the river bed at a depth from 7 to 15 m, and floodplain sites flooded by the rising spring water, on pebbles and rarely on gravelly-sand bottoms.It generally behaves as a resident fish.Does not undertake long migrations.Their main food in all rivers is benthic organisms, mainly insect larvae ( Trichoptera, Chironomidae, Ephemeroptera, Plecoptera, and Simuliidae ); small mollouscs (Sphaeridium spp., Pisidium spp. and Viviparus), annelids, other invertebrates , and also fish eggs, including those of other acipenserids, are also included in their diet. Young specimens feeds mainly on trichopteran and chironomid larvae. In the Volga river near its mouth, gammarids account for over 90 % of the food by weigh in young specimens. With increasing size, the role of tricopterans increases while that of chironomidae decreases.|
Males reach sexual maturity at an age of 3-6 years old, one to two years earlier than the females. The spawning periodicity remains open: spawn every year or only after a pause (shorter for males than for females) of one or more years?. Possibly, in the northern part of the range, the onset of sexual maturity would be later, and a considerable proportion of the adult specimens would not reproduce during every spawning season (Sokolov & Vasilev, 1989). During the spring floods they do swim upstream in the river for spawning. Males appear at the spawning ground before females at the water temperature from 9 to 11 ºC. Females reach the spawning ground later, at a water temperature from 12 to 13 ºC.
The optimal water temperature for the reproduction of sterlets ranges from 12 to 17 ºC.
The sterlet has the shortest life span (22-24 years old) in the genus Acipenser and females live longer than males.
|Maximum size 125 cm and a weight of 16 kg; usually below 100 cm and 6 to 6,5 kg.|
|Interest to Fisheries|
|The sterlet is a very important commercial fish. They were caught with nets, fish traps, willow baskets, and with barbed lances. At the present time, most of the sterlets captured come from the Danube River system.|
They are usually marketed alive, and rarely refrigerated, frozen or smoked. Males of this species are used to produce the bester, the first generation hybrid with beluga (Huso huso) females. The sterlet is an important fish in aquaculture, reahing sexual maturity in containers filled with warmed water (Sokolov & Vasilev, 1989 ).
Sterlet a. czeczuga .|
|RUSSIAN FED. :
|UNITED KINGDOM :
|There are more synonyms that listed up. Birstein & Bemis (1997) consider that all intraspecies, forms and subespecies of A.ruthenusdescribed by different authors (see Berg, 1948 and Sokolov & Vasilev, 1989) are invalid until detailed molecular and morphological studies of different forms within these species can be performed.|
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