Sterlet

Sturgeon (Acipenser ruthenus) inhabit the river basins of the Caspian, Azov, Black Sea and Baltic Sea.
Sturgeon - freshwater fish, constantly living in the Volga River and its tributaries, the Ob, Irtysh. Occasionally sturgeon occurs in the western coast of the Caspian Sea, where the occasional instances come in Kourou. Sturgeon is known in the Danube - to Vienna, in the literature there are indications of a starlet in the Gulf of
Kvarner (northern Adriatic Sea). Through a system of channels starlet has penetrated into the Northern Dvina, pools Ladoga and Onega lakes. In Siberia, the spread in the Ob, Irtysh, Yenisei.
In Pyasine, Hatanga, Lena and further to the east, and in the Amur sturgeon is not (in Amur sturgeon transplanted Ob). Most of the rivers are ostroryly (typical form of the Berg) and roundnose form starlet.
Of the Northern Dvina River sturgeon were transplanted into the river Daugava (Western Dvina), in Mezen River Niemen, Onega, Pechora, to Shuya (the basin of Lake Onega). In addition, from the Ob Ob transplanted into the Amur sturgeon and sturgeon hybrid of the sturgeon. Transplanted starlet in some lakes. Roundnose (winter) sturgeon in the Volga and Kama rivers rising faster than ostroryly, it is more than average, more prolific. Conventional weight and length of fishing sturgeon 0.5-2 kg and 30-65 cm, rarely 3-4 kg and 80-90 cm, as an exception - 6-8 kg. The greatest weight of 16 kg sturgeon and the length of 100-125 cm Sexual maturity occurs in males starlet in 3-7 years (mostly 4-5 years) in females - in 5-12 years (mostly 7-9 years) after reaching lengths 28-34 cm Fertility Ob Sturgeon 6-45 thousand eggs, Irtysh starlet - 6-16 thousand eggs, Severodvinsk 4-140 thousand eggs.
Sturgeon spawn in 1-2 years. Males become sexually mature at the Volga at the age of 3 years, females spawn on the 6th year. On the Volga, there are winter and spring race. Sturgeon feed on invertebrates, mainly insect larvae sitting on sunken driftwood. Chironomid larvae devour. Sturgeon in nature forms a cross between the sturgeon and stellate sturgeon ("thorn sturgeon", "Sevruga thorn"). "Sturgeon spike" is not rare on the Volga, "Sevruga spike" is known on the Volga, Don and the Danube. In the Ob and Yenisei well-known cross between Siberian sturgeon and Siberian sturgeon (the so-called "Fire"). On the Volga, through artificial insemination produced viable hybrids x sturgeon sturgeon and sturgeon sturgeon.