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Sturgeons – contemporaries of dinosaurs
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common in the Volga; the starred sturgeon ship is common in the Volga, 
Don, and Danube Rivers. A hybrid of the Siberian sturgeon and the Siberian 
sterlet (the so-called “koster”) is well-known in the Ob and Yenisei Rivers. In 
the Volga, through artifi cial fertilization, viable hybrids have been achieved: 
sturgeon x sterlet and sterlet x sturgeon. Beluga-sterlet hybrids named 
“bester” were moved to the Sea of Azov and some water reservoirs.
Nowadays, the number of sterlets in the Dnepr, Don, Kuban, Ural, Sura, 
and the Upper and Middle Kama Rivers has fallen considerably, and it has 
become a protected species here.

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G.M.Palatnikov,  R.U.Qasimov
124
STURGEONS IN WATER
RESERVOIRS OF OUR PLANET
Apart from the six species of sturgeon inhabiting the Caspian basin 
described above, at least 18 more species relating to the order Acipenseriformes 
are currently classifi ed. These include the representatives of the sturgeon 
(Acipenseridae) and spadefi sh (Polyodontidae) families.
Adriatic sturgeon (Acipenser Naccaril Bonaparte, 1836):
A rare, poorly studied species. Not large: as an exception, it can reach 2 m 
in length and 25 kg in weight, but usually is far less.
It is very similar to the Russian sturgeon A. gueldenstaedti,  may be its 
deviated intraspecifi c form. It has larger number of gill rakers – 30-35, while 
the Russian sturgeon usually has less than 30. The Adriatic sturgeon has 10-
14 dorsal scutes, 32-42 lateral scutesand 8-11 ventral scutes. The dorsal fi n 
contains 36-48 rays, and the anal fi n – 24-31 rays. The body color varies from 
grayish-brown to almost black; the belly is whitish.
It is a diadromous species. For spawning, it enters the Po, Adij e, Brenta, 
Liventsa, Tsetina, and other rivers of northern Italy, Yugoslavia, and Albania.. 
In seas, it stays near the shore, at depths of between 10 and 40 m, usually in 
close proximity to river mouths. It migrates to the rivers of Italy during the fi rst 
months of the year and stays in fresh water until October. Spawning takes place 
in February-March. Its growth, reproduction, fecundity, egg development, 
feeding, and other aspects of its biology have not been studied.
Due to its rarity, this sturgeon species has no commercially value. No 
data on its numbers is available. Currently, att empts at artifi cial breeding are 
being made.
Amur sturgeon (A.schrenckii) – Amur River basin.
Common name: Buryat – kilimy; Chinese – tsilifu.
The Amur sturgeon is very close to the Siberian sturgeon, from which it 
diff ers in the form of its gill rakers: they are not rhipidate, but unimucronate 
and smooth. It is possible that the Amur sturgeon is just a subspecies of the 
Siberian sturgeon.

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Sturgeons – contemporaries of dinosaurs
125
It is common in the Amur River basin, from the estuary to the Shilka and 
Argun Rivers. It has semi-anadromous and non-anadromous forms; the latt er 
is represented with a number of local populations. It is 2 m in length and up 
to 50 kg in weight (up to 160 kg in the past). Males reach sexual maturity at 
the age of 10-13 years; females – at the age of 11-14. Spawning takes place in 
the Amur River channel in May-June. Main spawning grounds are located 
upstream from the city of Nikolayevsk-na-Amure. Fecundity makes between 
29,000 and 434,000 eggs. Based on the nature of its diet, the Amur sturgeon is 
a typical benthic feeder.
Atlantic sturgeon 
Acipenser sturio
 L., 1758
Atlantic sturgeon 
Acipenser sturio
Common names: Baltic or German osetr  (Russian);  sturgeon (English); 
Stor (German); stb’rje Norwegian); jesiotr (Polish); sampi (Finnish); esturgeon 
(French)
Endangered species. Placed on the  Red List of the International Union 
for Conservation of Nature and Natural Resources (IUCN) (Category I), the 
Red List of the USSR, and on a list of specially protected species of fi sh in 
Europe.
Very large sturgeon, exceeding 3 m in length and 300 kg in weight.  It has 
9-16 dorsal, 24-40 lateral, and 8-14 ventral scutes, as well as 15-29 gill rakers. 
The dorsal fi n contains 30-50 rays, and the anal fi n – 22-33 rays. Its scutes are 
larger and thicker than those of a Russian sturgeon of the same size, and they 
are radially striated. The spine in the pectoral fi n is very strong. The snout is 
more elongated than that of the Russian sturgeon. Barbels are located closer 
to the mouth than to the snout end. The body color of adult fi sh varies from 
grayish-green and grayish-brown to bluish-black.
It is a diadromous fi sh and in the past it entered many large European 
rivers – the Neva, Western Dvina, Neman, Visla, Oder, Elba, Rhine, Seine, 
Thames, Trent, Loire, Gironde, Duero, Guadalquivir, Rhone, Po, Danube, 
and others. In the north, it was found as far north as Iceland and the White 

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G.M.Palatnikov,  R.U.Qasimov
126
Sea; in the south – as far as the Mediterranean Sea and North Africa. It is 
likely that the non-anadromous form of this fi sh inhabited Lake Ladoga. 
Now this sturgeon species has completely disappeared in a vast portion of 
the geographic area (Map 9). Very sparse populations were preserved in the 
basis of the Gironde (France), Guadalquivir (Spain), Po (Italy), and Rioni 
(Georgia) Rivers.
It lives in waters of ocean salinity, has been observed at depths of 200 m, 
and makes lengthy migrations. The age of maturity diff ers in diff erent parts 
of the area. Generally, the southern populations mature 2-6 years earlier than 
the northern populations. In the Gironde River, sturgeon males mature at 
the age of 13-15 years with a length of 125 cm; females – at 16-20 years with a 
length of 155 cm. In the Rioni River, male sturgeon become adults at 7-9 years 
with a length of 96-110 cm; females – 8-14 years with a length of 137 cm. It 
enters rivers from January through October; however, the migration peak 
falls on the spring fl ood (April-May). Males migrate fi rst, usually 2-3 weeks 
earlier than the females. The Atlantic sturgeon would swim long distances up 
the large rivers: the Danube – almost 1,000 km; the Oder – 500 km; the Rhine 
– 850 km. Females prevail over males in populations. The sturgeon sex ratio 
in the Rioni River is 1.3:1; in the Guadalquivir – 3:1. The spawning period 
diff ers in diff erent parts of the area. In the rivers of the Baltic Sea, spawning 
would take place from June through August, and in the Black Sea (the river 
Rioni) – in May-June.
Spawning grounds are stretches of a river that have a high-fl ow velocity 
and a rocky or pebbly bott om. It spawns in a wide range of temperatures – 
from 7.7 to 22° C. The absolute fecundity signifi cantly varies from 200,000 to 
5.7 million eggs. For sturgeon from the Rioni River, the number is 790,000-
1,820,000 eggs. Female sturgeon in Guadalquivir River lay between 289,000 
up to 1,412,000 eggs. The eggs are from 2 to 3 mm in diameter. Depending on 
water temperature, egg development takes between 3 to 14 days. During the 
fi rst year of life, juveniles migrate to river estuaries, where they live in brackish 
water up to the age of 2-4 years, aft er which they migrate to the sea.
The Atlantic sturgeon diff ers from other European sturgeon species by its 
more rapid growth, coming close to the beluga in this category. The highest 
recorded age of a sturgeon is 48 years.
Juveniles in rivers feed on maggots, worms, crustaceans, and mollusks. 
Adult sturgeons feed on benthic organisms (mollusks, polychaetes, shrimp) 
and minor fi sh (sand eels, gobies). In the Black Sea, anchovy Engraulis 
encrasicholus is the main prey. It continues feeding in winter, as well.

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