A riverine species.

Habitat: At sea, shallow coastal and estuarine zones. In freshwaters, in deep parts of large rivers with moderate to swift current. Spawns in strong current (1-1.5 m/s) in large and deep rivers on stone or gravel bottom.

Biology: Anadromous and freshwater populations (freshwater populations existed in the Danube and Volga - both are now extinct). A complicated pattern of spawning migrations includes spring and autumn runs. Individuals migrating in spring enter freshwater just before spawning; they tend to spawn in lower reaches of rivers (320-650 km in the unregulated Ural). Individuals migrating in autumn overwinter in rivers and spawn the following spring further upstream (900-1200 km in the Ural).

Males reproduce for the first time at 8-13 years, females at 10-16. Generation length (average age of parents of current cohort) is estimated to be 15 years under natural circumstances, but due to the impacts this species is facing the generation length ranges from between 12 years in the Caspian Sea to over 20 in the Danube. Females reproduce every 4-6 years and males every 2-3 years in April-June, when the temperature rises above 10°C. Larvae drift on currents; juveniles then move towards shallower habitats, before migrating to the sea during their first summer. They remain at sea until maturity. The Russian Sturgeon feeds on a wide variety of benthic molluscs, crustaceans and small fish.

ACCCGTTGATTCTTTTCTACTAACCACAAAGATATTGGCACCCTGTATTTAGTATTTGGTGCCTGAGCAGGCATAGTCGGCACAGCCCTC---AGCCTTCTGATCCGTGCCGAACTGAGCCAACCCGGTGCCCTGCTTGGCGAT---GATCAGATCTACAATGTTATCGTTACAGCCCACGCCTTTGTCATGATTTTCTTTATAGTAATACCCATCATAATTGGCGGATTCGGAAACTGACTGGTCCCCCTAATA---ATTGGGGCCCCAGACATGGCATTTCCTCGCATGAACAATATGAGCTTCTGACTCCTACCCCCATCCTTCCTACTCCTTTTAGCCTCCTCTGGGGTAGAGGCCGGAGCCGGCACAGGGTGAACTGTTTACCCTCCACTGGCGGGAAACCTGGCCCATGCAGGAGCCTCTGTAGACCTA---ACCATTTTCTCCCTTCACCTGGCTGGGGTTTCGTCCATTTTGGGGGCTATTAATTTTATTACCACCATTATTAACATGAAACCCCCCGCAGTATCCCAATATCAAACACCTCTATTTGTGTGATCTGTATTAATCACGGCCGTACTCCTCCTACTATCACTGCCAGTGCTAGCTGCA---GGGATCACAATGCTCCTAACAGACCGAAATTTAAACACCACCTTCTTTGACCCAGCCGGAGGAGGAGACCCCATCCTCTACCAACACCTATTTTGATTCTTTGGCCACCCAGAGGTATATATTCTAATTCTACCGGGATTCGGCATAATCTCCCATATTGTGGCATACTATGCCGGCAAAAAG---GAACCTTTTGGCTACATAGGGATAGTATGAGCTATAATGGCCATTGGGCTACTAGGCTTTATCGTATGAGCTCATCACATGTTTACAGTTGGAATGGACGTAGACACACGGGCCTACTTTACCTCCGCCACAATAATTATTGCCATCCCCACAGGTGTCAAAGTCTTTAGCTGATTG---GCCACCCTTCATGGTGGT---TCAATTAAATGAGATACCCCTCTACTTTGAGCCTTAGGCTTTATCTTCCTATTCACAGTGGGAGGCTTAACGGGAATTGTCTTAGCCAACTCGTCTCTAGATATTGTACTTCACGACACCTACTACGTTGTAGCACATTTCCACTATGTA---TTATCAATGGGAGCTGTGTTCGCCATTATAGGGGCCTTCGTACACTGATTCCCGCTTTTCACGGGTTATACACTACACGGCACCTGATCCAAAATCCACTTTGCCGTAATATTTGTAGGTGTCAATCTAACATTCTTCCCCCAACACTTCCTAGGCCTCGCAGGAATGCCTCGC---CGATACTCAGACTACCCAGACGCATACGCC---CTATGAAACACCGTCTCCTCAATCGGCTCACTAATCTCATTAGTTGCTGTGATTATATTCCTATTTATTCTGTGAGAAGCATTCGCGGCTAAACGAGAAGTA---ATGTCAGTAGAACTAACAACCACAAAT
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Red List Category

Red List Criteria

Version

1996

Sturgeon Specialist Group

Red List Category

Red List Criteria

Version

1996

Sturgeon Specialist Group

Red List Category

Red List Criteria

Version

1996

Sturgeon Specialist Group

Red List Category

Red List Criteria

Version

2010

Gesner, J., Freyhof, J. & Kottelat, M.

Pourkazemi, M. & Smith, K.

Justification

History

• 1996
  Endangered

The species wild native population has undergone major decline which is currently occurring. But due to the large levels of stocking (particularly Russia and Iran) the exact levels are unknown. According to CITES (2000) Russia released 25 million fingerlings into the Vologa between 1979-80, 35 million between 1981-85, 40.8 million between 1986-90, 42 million between 1991-95 and 28 million 1996-98; Iran released 300,000 fingerlings in 1994 which has risen nearly every year to 960,000 in 1999.

Despite this level of stocking, fisheries catches have fallen, particularly from the early 1990s in the Caspian. According to FAO fisheries statistics (FAO 2009) global catches fell from 4,250 tonnes in 1992 (first available catch data) to 67 tonnes in 2007 (last available catch data), a decline of 98% in 15 years. The average catch from 1992-1999 (8 year period) was 1,531.75 tonnes, whereas the average catch from 2000-2007 (8 year period) was 175.37 tonnes, a decline of 88.5%.

Data from the Caspian Sea (Khodorevskaya et al. 2009) shows similar declines: catches were between 6,000 and 9,000 tonnes per year in the 1960s to a peak of around 14,500 tonnes in the late 1970s early 1980s to less than 1,000 per year from 2000 to 2008. The estimated spawning stock biomass in the Volga has also drastically declined, from 13,200 tonnes (1961-65) and 22,200 tonnes (1966-70) to 1,000 tonnes (1996-97) and 1,000 tonnes (1998-2002). Average number of spawners (1,000 individuals) passing fishery zones to the spawning grounds in the lower Volga (per year) has declined by 88% from the 1962-75 average to the 1992-2002 average.

Romanian catch data (Danube) shows that in 2002, 3,726 kg was caught; in 2003, 1,499 kg; in 2004, 440 kg; and in 2005, 37 kg, showing a 99% decline in just four years (Paraschiv et al. 2006). A Juvenile Production Index (evidence of breeding) for the Danube (Romania) also shows a decline: CPUE was just over 0.7 in 2000, et al. 2006; Knight et al. 2010).

Decreasing

Most spawning sites have been lost due to dam construction. The Caspian basin lost 70% of spawning grounds since the 1950s, mainly due to the construction of hydroelectric power stations; the Ural is now the only river in the basin with unregulated flow. Flow regulation of the Kuban River has led to the loss of 140,000 ha, and damming of the river Don has removed 68,000 ha spawning ground. For example, in the Yugoslavian section of the Danube, the annual catch dropped from 14,636 kg in 1983 to 1,636 kg in 1985 (a decline of just under 90%), this is believed to be due to the construction of the Djerdap (Irongate) II dam which was constructed in 1984, leaving no accessible spawning grounds for the species in the upstream reaches and in former Yugoslavia (CITES 2000).

Poaching and illegal fishing, which appears to be increasing, is also a threat to the species. Enforcement of legislation regulating the fishery for the species appear to be lacking. In the Caspian Sea and Sea of Azov the illegal sturgeon catch for all species was evaluated to be 6 to 10 times the legal catch (CITES 2000). Bycatch is also a threat to the species (in both marine and freshwater).

High levels of pollution (from oil and industrial waste), in both the Black and Caspian Sea basins have altered hormonal balance, and increased the number of hermaphroditic fish. Pollution levels are now decreasing since the break up of the Soviet Union (Levin, 1977 in CITES 2000). In 1990, 55,000 sturgeon were found dead on the shore of the Sea of Azov as the result of pollution.

Genetic pollution is also a potential threat as stocks are moved to different locations (e.g. Caspian stocks moved to Sea of Azov).

The Allee affect is also a potential threat to the species.

Restocking measures are ongoing, however stocks are continuing to decline. In the early 1990s, between 30-55% of the Caspian stock reportedly originated from hatcheries (Barannikova 1995 in CITES 2000, Khodorevskaya et al. 2000). In Russia, between 1991 and 1998, 70 million fry of A. gueldenstaedtii were released in the Volga river and just over 32 million fry into the Sea of Azov.

The species is not fully protected in any range state, though licenses are required in most countries and Iran has banned private sturgeon fisheries. Overall, however, enforcement measures seem to be lacking. Fish lifts and artificial spawning grounds have been introduced to parts of the Caspian region (CITES 2000) without much success. This species was listed on CITES Appendix II in 1998.

Gene bank of live specimens and cryopreservation is ongoing in Russia and Iran.