Our Neighborhood's Biodiversity Map

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Europe
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Shared by : Arushi Madan (UK)
Distribution and habitat Native : Azerbaijan; Georgia; Hungary; Iran, Islamic Republic of; Kazakhstan; Russian Federation; Serbia; Turkey
Status : Critically Endangered
Introduction
The common name of this species is "Ship Sturgeon" or "Fringebarbel Sturgeon". The scientific name "nudiventris" stems from Latin and means "naked belly". This is due to the fact that the bony plates on the bellies of adult fishes get rubbed off with age and are often almost fully lost. The species is known from the Black, Aral and Caspian seas. However, it is extirpated from the Aral Sea, nearly extirpated in the Black Sea basin and there are only occasional records from lower Volga. The only remaining population occurs in the rivers Ural (Russia, Kazakhstan) and possibly the Rioni (Georgia - last recorded 1997 through bycatch; there are no recent surveys), and possibly the Safid Rud (seven individuals recorded in 2002) in Iran. In Europe, it is thought that few individuals exist in the Danube - indeed it is considered possibly extinct. It is suspected that the species has undergone a population decline of more than 90% in the past three generations (estimated at 45 years) which is expected to continue. It is believed the species is on the verge of global extinction. The largest population is in Lake Balkash (introduced for commercial reasons) which is outside the species natural range.

Its skin is used as leather, Caviar is used as cosmetic and medicinal purposes. The cartilage is used medicinal use, the intestine is used as sauce (food) and to produce gelatine, and the swim bladder is used as glue. The Ship Sturgeon feeds mainly on bottom dwelling organisms such as insect larvae, mussels, snails, crabs and small crayfish. The optimum temperature range for the egg development of this species is between 11 and 15 °C and spawning occurs when temperatures reach this level.
Appearance
The Ship Sturgeon is a rather large species and can reach lengths of more than 2 meters. A maximum age of 36 years was recorded in the Kura River (Caspian Sea Basin). It takes males and females up to 9 and 14 years, respectively, to mature. The females carry 200,000 to 1,300,000 eggs, depending on their size.
Possibly extinct
Romania In a lot of rivers this species occurs only in its sea-migrating form. It inhabited the Black, Azov, Caspian and Aral Seas, from where the spawners migrated upstream the rivers for spawning. However, in the Danube River the Ship Sturgeon has solely been documented in its freshwater form that remains in the river throughout its entire life.
A nudiventris was formerly recorded in the Lower and Middle Danube (occasionally also in the Delta) - migrating upstream as far as Komarno, 1,766 km from the river mouth, and even Bratislava at km 1,869 - but only rarely entered Austrian waters.
Occasionally it also occurred in the following Danube tributaries: Vah, Tisza, Sava and Drava, and in the lower sections of the Prut and Siret.
Habitat
At sea, close to shores and estuaries. In freshwater, deep stretches of large rivers. Juveniles in shallow riverine habitats. This species spawns in strong-current habitats in main courses of large and deep rivers on stone or gravel bottom.
Threats
Over harvesting, bycatch and illegal fishing (poaching) along with dams, water abstraction and drought has led to the loss of spawning habitats/ground and has caused massive population declines.
Conservation Actions
There is a zero quota of exporting of Caviar (CAB) but there is still a catch for domestic use. Iran and Russia have established gene bank conservation for this species for both live specimens and cryopreservation with DNA and tissue samples. The 2004 progeny have been produced from captive bred individuals - juveniles were released into the Don and Kuban rivers - and there are between 15 and 20 'farms' in Russia (Chebenov pers comm.). In Iran 80,000-1 million fingerlings (3-5 g each) (from ranched individuals) are released annually to the Caspian Sea (Pourkazemi pers comm.)

Sources/References :
http://www.iucnredlist.org/details/225/0
http://www.dstf.eu/species/acipenser-nudiventris/

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