Acipenser baerii

The Latin name of Siberian sturgeon is Acipenser baerii, and its foreign name is Siberian sturgeon. It has no subspecies.

The appearance and biological characteristics of the Siberian sturgeon are similar to those of the small-bodied sturgeon (Acipenser ruthenus). In the Ob River, the Irtysh River (a tributary of the Ob River) and the Yenisei River, the Siberian sturgeon can naturally hybridize with the small-bodied sturgeon.

Siberian sturgeon lives in fresh water, has strong adaptability, is resistant to low temperatures, has large variations in morphology and biological characteristics, has a wide range of diets, and has great growth potential. There are two main ecological types of Siberian sturgeon, namely semi-migratory and sedentary. Semi-migratory populations usually live in estuaries or estuary delta waters. After sexual maturity, they go upstream along the river for a long distance (1,600-3,000 kilometers) to spawn, and hibernate in low-lying areas of the riverbed during the migration process (called "winter sturgeon"). Sedentary populations mainly live in the branches of the middle and upper reaches of the river, and there is no obvious migration phenomenon. The number of sedentary populations is significantly less than that of semi-migratory populations. The Siberian sturgeon in Lake Baikal is a special ecological type: lake-river type. They usually live in lakes, and in the breeding season, they migrate about 1,000 kilometers to the river (Seleng River) to lay eggs.

The Siberian sturgeon mainly feeds on benthic animals, mainly chironomid larvae. In estuaries and deltas, the food mainly includes amphipods and polychaetes. While eating animal food, it also eats organic debris and sediment, which sometimes account for more than 90% of the contents in the stomach. Small fish can sometimes be seen in the stomach contents of the Siberian sturgeon introduced to the Baltic Sea.

The growth rate of the Siberian sturgeon in different natural water bodies varies greatly, and the fastest growing ones are the Siberian sturgeon in the Ob River and Lake Baikal. Studies have found that there is no gender difference in the growth rate of the Siberian sturgeon. After the Siberian sturgeon was transplanted to European waters, its growth rate was significantly accelerated. In 1964, the Siberian sturgeon juveniles in Lake Baikal were transplanted to the Baltic Sea. At the end of the second year, their total length and weight reached 46-50 cm and 0.415-0.500 kg respectively; in the third year, they reached 60 cm and 1.0-1.2 kg. In August and September of the third year, a 69 cm long, 1.69 kg and a 78 cm long, 2.65 kg individual were caught respectively. One year after the Siberian sturgeon juveniles in Lake Baikal were released into Lake Ladoga, they weighed 0.20-0.35 kg. Under warm water culture conditions (10℃ in winter, 25-30℃ in summer), the growth rate of Siberian sturgeon can reach 10 times the growth rate under natural conditions.

The sexual maturity of Siberian sturgeon is later than those sturgeons distributed in the south. Female sturgeons first mature at the age of 19-20 years and male sturgeons at the age of 17-18 years. Most female sturgeons mature at 25-30 years and most male sturgeons mature at 20-24 years. The Siberian sturgeon in the Lena River matures relatively early, with female sturgeons maturing at 11-12 years and male sturgeons maturing at 9-10 years. In the waters of Siberia, the reproductive cycle of female Siberian sturgeons is at least 3-5 years, and that of male sturgeons is generally 2-3 years. Under artificial warm water conditions, the sexual maturity age of Siberian sturgeons can be advanced and the reproductive cycle can be shortened. In the warm water breeding bases of the former Soviet Union and France, female Siberian sturgeons from the Lena River mature at 7-8 years and have a reproductive cycle of 1.5-2 years; male sturgeons mature at 3-4 years and can reproduce every year.

In the waters of Siberia, Siberian sturgeon spawns from late May to mid-June, with a wide range of water temperatures, 9-18°C. In the western region (Obi-Irtysh River), Siberian sturgeon spawn earlier than in the eastern region (Lena River), and the optimal water temperature for spawning is 11-16°C. In warm water aquaculture in Europe, the water temperature required for spawning comes earlier, and the time to obtain eggs is from January to April. After the Siberian sturgeon was transplanted into natural waters in Europe, there were no reports of its natural spawning.

There are two types of Siberian sturgeon: one-step spawning migration and two-step spawning migration. Unlike most other sturgeon species, the male-female ratio of Siberian sturgeon in the spawning grounds is close to 1:1. It is known that in the Ob-Irtysh River, when the average water temperature is 13.4℃ and 20.7℃, the accumulated temperature required for the hatching of Siberian sturgeon embryos is 2345℃·hour and 1697℃·hour respectively. The average length of the newly hatched fry is 10.5 mm and the weight is 13.9 mg. When the average water temperature is 17-18℃, the fry begin to eat exogenous food on the 4th or 5th day after hatching, at which time they are 22 mm long and weigh 35.4 mg on average.

Since the 1980s, due to the influence of river water diversion, the structure of the Siberian sturgeon breeding population has changed, and the breeding population has become older and the sex ratio has increased. In addition, the number of immature individuals in the spawning grounds has increased.

The Siberian sturgeon is one of the most economically valuable fish in Siberia. The highest production appeared in the 1930s, with an annual catch of 1,280-1,770 tons, of which the Ob River accounted for more than 80%. Since then, the production of Siberian sturgeon has dropped sharply. In the Ob River, the highest annual catch was 1,401.1 tons from 1932 to 1938, which dropped to 152.7 tons in 1979, and only about 9.2 tons were allowed to be caught in 1994.

The main reasons for the deterioration of Siberian sturgeon resources are three aspects: the reduction of spawning grounds caused by dam construction, overfishing (mainly poaching) and environmental pollution.

From 1976 to 1981, 390,000 artificially propagated and cultured young Siberian sturgeons were released into the Bratsk Reservoir on the Angara River in south-central Siberia. But until now, the artificial propagation and release of Siberian sturgeons has not played a big role in the recovery of Siberian sturgeon resources. In addition to the artificial propagation and release in Lake Baikal, Siberian sturgeons from the Lena River and other water systems are mainly used for commercial breeding.

Listed in the "Red List of Endangered Species of the World Conservation Union" (IUCN 2009 ver 3.1) - Endangered (EN).

Listed in the "Red List of Endangered Species of the World Conservation Union" (IUCN 2019 ver 3.1) - Critically Endangered (CR).

Listed in the "Convention on International Trade in Endangered Species of Wild Fauna and Flora" (CITES) - Appendix II.

Listed in the "List of National Key Protected Aquatic Wildlife for Artificial Breeding (Second Batch)" issued by the Ministry of Agriculture and Rural Affairs of China on July 29, 2019.

Listed in the second level of the "List of National Key Protected Wildlife in China". (Wild populations only).

Protect wild animals and stop eating game.

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Waters of Origin: Siberian sturgeon is mainly distributed in rivers flowing into the Arctic Ocean in Siberia, Russia, from the Ob River in the west, through the Yenisei River, Payashina River, Khatanga River, Anabar River, Olenek River, Lena River, Indigirka River, to the Kolyma River in the east. In addition, Siberian sturgeon is also distributed in Lake Baikal, forming a land-locked population of Siberian sturgeon.
Introduction site: In the late 1950s, people released young Siberian sturgeon from the Lena River and Lake Baikal to the Baltic Sea, Volga River and Lake Ladoga. Although the growth and distribution of Siberian sturgeon in these waters were observed, Siberian sturgeon was easily caught in these waters, especially because these waters did not have the natural conditions to induce Siberian sturgeon to spawn, so Siberian sturgeon ultimately failed to form a stable natural population in these European waters. In the 1970s, adult Siberian sturgeons were introduced to France

The whole body is covered with 5 rows of bony plates, and the snout length accounts for less than 70% of the head length. There are 4 snout barbels; the snout tip is tapered, the edges on both sides are rounded, and there is a water blowhole on the head; the mouth is horizontal, the opening is downward, and the snout barbels are round; the highest point of the body is not at the first dorsal plate, and the first dorsal plate is not the largest plate; there is no post-dorsal fin plate and post-hip plate; the lateral plates are usually similar in color to the trunk. The gill rakers have several tubercles (usually 3).
The Siberian sturgeon can be up to 200 cm long, weigh 200-210 kg, and 60 years old. Individuals in the eastern region (Lena River and Kolyma River) are significantly smaller, with a maximum weight of no more than 10-16 kg.
The head length of the Siberian sturgeon is 16.7-27% of the total length, and the body height is 9-16.6% of the total length. Like the small sturgeo