Fish book son indd

G.M.Palatnikov,  R.U.Qasimov
104
CASPIAN STURGEONS
BELUGA – HUSO HUSO (LINNAEUS, 1758)
 Type:    Chordata 
 Group:   Osteichtyes
 Order:   Acipenseriformes, Berg, 1940 
 Family:   Acipenseridae Bonaparte, 1832
 Genus:   Huso Bramdt, 1869
Common names: Russian – beluga; Azerbaij an – Agh-kulag-nyarya, gyuzgi-
burun; 
Iranian –Phil mahi, Beluga; English –great sturgeon
Beluga has a torpedo-like body. The chorda is preserved. The caudal fi n 
is heterocercal. Spiracles are well developed. Branchiostegal membranes are 
interconnected. The snout is short, pointed, slightly upturned, soft  from above 
and on both sides, uncovered with bone scutes. The inferior mouth, which is 
crescent shaped when closed and half-moon-shaped when open, does not 
transition to the sides of the head; the lower lip is interrupted. Barbels have 
foliate appendages. The number of dorsal scutes is 10-15; lateral – 40-51; 
ventral – 9-11; gill rakers – 19-30. 
Intraspecifi c  forms. Subspecies Huso huso ponticus (Salnikov and 
Malyatskiy, 1934) – the Black Sea beluga. Subspecies Huso huso maeoticus 

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Sturgeons – contemporaries of dinosaurs
105
(Salnikov and Malyatskiy, 1934) – the Sea of Azov beluga. Within the Caspian 
Sea, there are three forms: the Kura, Ural and Volga beluga. In terms of 
morphology, they are almost similar, but their maturity, length, and fertility 
diff er. There are also the faster and slower run forms of beluga.
It inhabits water bodies all over the world; for spawning, it enters the 
rivers of the Caspian basin: Kura, Volga, Ural, Terek and Sefi d Rud.
It is found in the basins of the Sea of Azov and the Black Sea; single 
specimens have been recorded in the southern part of the Adriatic Sea, and 
some species were found in the rivers of Anatolia. Beluga fatt ens in shallow 
waters at 1.5 - 30 m depths. In winter, belugas are found at 130-180 m depths, 
but most fi sh prefer 10-60 m depth. Beluga migrates within the area for 
spawning, wintering and feeding.
Beluga, as a predator, actively searches for and catches the food. Fry 
initially has mixed food: crustaceans, mollusks and fi sh. During the fi rst 
month (June) of summer, beluga’s fry eats mostly crustaceans. However, due 
to shortage of crustaceans during the low-water season, the fry eats gobies.
Beluga fry (7.0-15.0 g), migrating down the river, feed on amphipods, 
larvae of chironomids, ephemeral fl ies and trichopterans, as well as 
oligochaetes, eggs and larvae of sturgeons and other fi sh. Larger species feed 
on the starred sturgeon and sturgeon fry.
When transitioning to active feeding, young beluga may show signs of 
anthropophagy (cannibalism). The adult beluga feeds mainly on fi sh. The 
beluga’s food may diff er depending on seasons and foraging sites. Some 
instances have been recorded when white-coat seal puppies were found in 
beluga stomach.
Beluga reaches maturity late. The majority of males reach maturity at the 
age of 12-15 years, and females – at the age of 15-20. In the Volga River, males 
reach maturity at the age of 10-15 years, and females – at the age of 16-22. The 
beluga lays its eggs on solid substratum: rocks, pebble, gravel, coarse sand, etc.
Aft er the construction of the Mingechavir hydroelectric station, no 
natural spawning areas for beluga remained in the Kura River. The beluga’s 
reproduction is being maintained only through breeding in commercial 
hatcheries.
For spawning, the Ural beluga uses pebble and gravel deposits upstream 
at a distance of 400-1200 km from the city of Atyrau. Approximately 70 
spawning sites were preserved with a usable area of 922 hectares. The majority 
of fast run belugas spawn on channel ranges at 6 - 12 m depths - at the river 

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G.M.Palatnikov,  R.U.Qasimov
106
section between the towns of Chapayevo (650 km from the Ural estuary) and 
Uralsk (850 km from the Ural estuary). Developing roes are found in the Ural 
River Delta, as well.
Spawning of the Volga beluga takes place in an unregulated section of 
the Volga River, downstream the Volgograd hydroelectric station dam – in an 
area between Volgograd and the sett lement of Kamenny Yar. The spawning 
substratum consists of fl agstone fragments, gaize, pebble, and coarse sand. 
Beluga spawns 10 - 30 m depths at the river high currents of 1-2.5 m/s.
Time of breeding. The faster matured beluga spawns at 7-11° C water 
temperature, while the slower matured – at 10-15° C.
No exact data is available on the frequency of beluga spawning. Males 
enter the river for re-spawning in 3-4 years, and females - in 4-6 years. 
Spawning of the Volga beluga takes place in early spring (end of April- 
beginning of May) at 6-16
0
C water temperature.
Fecundity. The fecundity of females is determined according to their mass, 
length and age. The length of the Ural beluga varies from 136 to 405 cm; 200-
260 cm-long fi sh are observed most frequently. In recent years, the average 
length of females has been 245.0 cm, and of males – 210.6 cm. Minimum age 
is 12 years; maximum – 39. The absolute length of adult species of the Volga 
beluga is 180 cm and more. The immature portion of the population dominates 
in the fatt ening  areas. Aft er reaching age of 11 (males) and 16 (females), 
individual species of beluga mature and begin migrating for spawning. At 
present, the maximum age of beluga males is 35-40 years; females are found 
at ages of between 16 and 50-55. The average weight of the Volga beluga 
ranges from 114.6 kg (females) to 62.8 kg (males) and the length is 239.7 and 
204.7 cm, respectively. The average age of male belugas – 22.7 years; female 
belugas – 17.7 years. Populational fecundity makes 1,971 million eggs. The 
older the belugas are, the higher their fecundity is. Currently, the average 
absolute fecundity of the Volga beluga varies from 680,000 to 800,000 eggs.
The beluga creates hybrid forms in nature, such as sterlet x beluga, beluga 
x sterlet, beluga x starred sturgeon, beluga x barbel sturgeon, and beluga x 
sturgeon.
The beluga x barbel sturgeon hybrid was obtained for the fi rst time at 
the Kura Experimental Fish Farm in Azerbaij an. This hybrid was successfully 
introduced to the Ropshin Lake of the Leningrad Region (Russia).
Viable hybrids – beluga x sterlet (bester) – were obtained in the Volga and 
Don using artifi cial fertilization.

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