Ship Sturgeon, Spiny Sturgeon, Bastard Sturgeon, Fringebarbel Sturgeon, Thorn Sturgeon
IUCN: СR; Bo (II); EUHD (V); RDBUkr: Зниклі
This species has been recorded from the Black, Azov, Caspian and Aral Seas, and some rivers (Danube up to Bratislava, Volga up to Kazan, Ural up to Chkalov, Don and Kuban, Rioni). It was introduced to Lake Balkhash (Kazakhstan), to the upper Illi River in China, and to River Syr-Darya (Aral basin) in the 1960s.
It is currently known from the Caspian Sea, where it ascends only the Ural river (where it naturally reproduces) and the Sefid Rud River (where there is no natural reproduction), where 5 fish were caught in 2002 (Parandavar et al. 2009). In the Black Sea, it ascends the Rioni (last recorded 1997 through bycatch (Zarkua pers. comm.)). In the Danube it was last recorded in 2003 in Serbia at Apatin (released alive) and in 2005 in Mura in Hungary (killed); both these caught fish were males (Simonovic et al. 2003; Streibel pers. comm.). In Romania, according to a fisherman survey carried out between 1996-2001, 15 individuals were caught by Romanian fishermen (last scientifically recorded in 1950s) (Suciu et al. 2009) .
Little catch data is available. It has not been caught in Ukraine for the past 30 years. In Kasakhstan 12 tonnes were caught in 1990, 26 tonnes in 1999; in Iran 1.9 tonnes were caught in 1990, 21 tonnes in 1999 (CITES Doc. AC.16.7.2), and 1 ton in 2005/6, with 0.5-1% of total sturgeon catch in Iran belonging to this species (in past 20 years) (Pourkazemi pers. comm.). According to Caspian Aquatic Bioresource Commission (CAB), since 2001/2 export quota for caviar is zero for all Caspian range states.
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.
Anadromous (spending at least part of its life in salt water and returning to rivers to breed), with some non-migratory freshwater populations. Males reproduce for the first time at 6-15 years, females at 12-22, with an average generation length of 15 years (but in the Danube, the average population age has now increased and in the Caspian Sea, the average population age is decreasing because of overharvesting). In most drainages, there are two migration runs, in spring and autumn. Individuals migrating in autumn remain in the river until the following spring to spawn. Females reproduce every 2-3 and males every 1-2 years in March-May and at temperatures above 10°C. Most juveniles move to sea in their first summer and remain there until maturity. Some individuals remain in freshwater for a longer period. Feeds on a wide variety of benthic fishes, molluscs and crustaceans.
This species has the highest relative fecundity for any sturgeon species (Chebanov pers. comm.).
- Котенко Т.И., Ардамацкая Т.Б., Дубина Д.В. и др. Биоразнообразие Джарылгача: современное состояние и пути сохранения // Вісник зоології. – 2000. – Спец. випуск. – 240 с.