|Scientific Name:||Acipenser baerii|
|Species Authority:||Brandt, 1869|
|Red List Category & Criteria:||Endangered A2bcd+4bcd ver 3.1|
|Assessor/s:||Ruban, G. & Bin Zhu|
|Reviewer/s:||Pourkazemi, M. & Smith, K.|
The species has undergone a sharp decline in both stock and recruitment. The stock decline started in the 1930s, when demand was significantly high, and continues to decline. From the 1930s to 1990s annual sturgeon catches have declined in the Ob (which is estimated to contain 80% of the global population) by 99.5%; in the Yenisei by 97.5% and Lena by 94.5%. Therefore the total global population decline is estimated to be 50-80% over the past 60 years. The three generation period of this species is 75-90 years. This decline is likely to continue into the future. Since the beginning of 1990s, stock abundance declines have mainly been caused by overfishing and dam construction (for hydropower). Also illegal catches cause declines, affecting the abundance mainly of the spawning stock. In all populations especially in populations of the Ob and Kolyma rivers abnormalities were observed in the development and functioning of the reproductive system up to complete sterility of females, caused by water pollution from mining. Abnormalities were observed in 80-100% of females in these rivers. Natural reproduction of the Ob River population has significantly decreased mainly due to damming. Restoration of the Siberian Sturgeon populations because of its late maturity, long intervals between spawns and low productivity of northern water ecosystems is extremely slow. The recent decline in recruitment caused by decline in spawner abundance, damming and abnormalities in development and functioning of reproductive system will translate into a future decline in adult stock. Noting the longevity of this species, restoration of the stock is expected to take several generations. Although this species is listed on CITES Appendix II, further actions are urgently required to ensure wild populations of this species are sustained. Based on the estimated population declines over the past 60+ years and the expected continued declines into the future, this species has been assessed as EN A2bcd+4bcd.
|Range Description:||This species is known from all Siberian rivers draining to the Kara, Laptev and East Siberian seas: basins of the Ob, Taz, Yenisei, Pyasina, Khatanga, Anabar, Olenyek, Lena, Yana, Indigirka, Alazeya (rarely) and Kolyma rivers, Lake Baikal (the Yenisei River basin) and rivers flowing to the lake – the Selenga, Barguzin and Upper Angara. It is most abundant in the Ob, Yenisei and Lena rivers.
This species is also native to the the Irtysh River, in the northwest of Xin jiang province, China. However, wild populations were extirpated from here in the 1950s; the small population that remains here is from stocking (Chen 2007).
Native:China; Kazakhstan; Mongolia; Russian Federation
|Range Map:||Click here to open the map viewer and explore range.|
The total population of Siberian Sturgeon is unknown. Direct counts and fishery statistics exist but are incomplete. However, a decline in catches of sturgeons within the main rivers of Siberia has been observed from the 1930s (Ruban 2005).
Based on commercial catch data, it is estimated that the Ob River basin contains more than 80% of the global population of this species (Chen 2007). In the Ob River basin, catches declined by ~99.5% from 1410 tonnes in 1935 to 6.7 tonnes in 1996. In the Yenisei River catches declined from 504 tonnes in 1934 to 10-12 tonnes in 2000s (a ~97.5% decline). In the Lena River catches declined from 190 tonnes in 1943 to about 10 tonnes in recent years (a ~94.5% decline) (Ruban 2005).
This species was extirpated from the northwest parts of Xin jiang province, China in the 1950s. The small population that remains here exists through stocking (Chen 2007).
|Habitat and Ecology:||
This species can be found in all types of freshwater benthic habitats in large rivers and lakes. It spawns in strong-current habitats in the main stream of large and deep rivers on stone or gravel bottom. Numerous spawning sites are located in lower and middle reaches of rivers. Spawning peaks at beginning of June, continuing until end of July.
Spawning periodicity is 3-5 years in females and 2-3 years in males. The generation length of the species ranges from 25-30 years (Chen 2007, Ruban 2005). In northeastern populations, females are twice the age of males (Ruban 2005). The average age at maturity for females is 11 (in Lena River) to 22 (in Lake Baikal), and 9-19 years for males.
|Major Threat(s):||The population decline all over the species range is a result of overfishing, damming (Ob, Yenisei, Angara) and poaching. Currently commercial fisheries are banned in the basins of the Ob and Yenisei rivers and the Lake Baikal. A decline in area of occupancy was observed in upper reaches of the Ob, Yenisei and Lena rivers (Ruban 2005). Dam construction at the Ob River resulted in 40% of sturgeon spawning grounds being lost (Gundrizer et al. 1983). At the main sturgeon rivers of Siberia (Ob and Yenisei) the high level of poaching was noted (Krokhalevskii and Mikhalev pers. com.). At the Ob River, natural reproduction of the sturgeon has also declined due to a high level of abnormalities in development and functioning of reproductive system caused by water pollution (Ruban 2005).|
The majority of 'conservation' measures historically in place for the Siberian Sturgeon were set up and controlled at local and national level. Their aims are often securing fishing rights, supporting local stock levels. The Ob River and Baikal Lake populations of the sturgeon are included in Red Data Book of Russian Federation. This means that commercial fishing of these populations is now prohibited.
The Siberian Sturgeon was listed in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) in 1998. An export permit can only be issued if the specimen was legally obtained and if the export will not be detrimental to the survival of the species.
For the last 10 years, eggs of this species (originating from Russia) are being reared in Chinese hatcheries and young are being released into the upper reaches of the Irtysh River, in the northwest part of Xin jiang province, China. No information is currently available on population numbers. This is being undertaken by the Ministry of Fisheries and Aquaculture (Chen 2008).
|Citation:||Ruban, G. & Bin Zhu 2010. Acipenser baerii. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 12 March 2014.|
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