State Museum of Natural History
Biodiversity Data Centre

Acipenser ruthenus Linnaeus, 1758

Vernacular Name Sterlet
Conservation status IUCN: VU; Be (III); Bo (II); EUHD (V); CITES (II); CarpRL: VU; RDBUkr: Зникаючі; RDBUkrCarp: NT
This species is known from rivers draining to Black, Azov and Caspian Seas; Siberia from Ob eastward to Yenisei drainages. Its current strong holds are the Volga, Ural and Danube systems. It was introduced in Pechora drainage in 1928-1950 and in Lake Ladoga basin (most likely not self-sustaining). Aquaculture has resulted in intentional and accidental introductions throughout Europe, without formation of self-sustaining populations. This species has formed self sustaining populations in reservoirs in Russia. Comprehensive catch data are not currently available but recorded catches in the Russian Federation decreased by nearly 40% between 1990 (116 tonnes) and 1996 (80.6 tonnes) (CITES 2000). In the Danube drainage, the only available catch data is from 1958 to 1981, where catches ranged from 117 tonnes in 1963 to 36 tonnes in 1979, with an average catch of 63.5 tonnes per year (CITES 2000). In the mid and lower Danube catches are not often reported as it is a small species so catch data is suspect. Surveys (Juvenile Production Index) show that there is good current spawning in the Danube in Romania, Hungary and Serbia upstream of dams (Paraschiv et al. 2006; Knight et al. 2010). In the mid Danube the species supported large scale fisheries at the end of the 19th century, though currently this is much smaller. Over the past 21 years (estimated three generations in the Danube), a decline has happened but it is unknown to exactly what extent. The population has shown some recovery since the 1980s as the pollution from agriculture has been reduced. Hungary has had a re-stocking programme but its success is in question due to lack of brood fish used in the stocking (Guti pers. comm. 2007, to Suciu). The Sterlet is found in large rivers, usually in the current and in deep water. As water level rises, it moves to flooded areas to feed. It spawns on gravel in strong-current habitats. It is a freshwater species; anadromous populations have been extirpated. Males reproduce for the first time at 3-5 years, females at 5-8 (Siberian populations mature later: males at 7-9 years, females at 9-12 years). The average reproductive age is about 10 years, but in the Danube this is lower (seven years) due to intensive fisheries. Females reproduce every 1-2 years and males every year in April-June when the temperature rises above 10°C. This species is largely sedentary; undertaking only short spawning migrations (322 km reported from Danube). There was a migratory population with large-growing individuals in Volga until end of 19th century, feeding in the northern Caspian Sea and moving upriver in autumn. The Sterlet feeds on a wide variety of benthic insect larvae and molluscs.
Book reference
  • Соколов Н.Ю. Каталог колекції круглоротих і риб Державного природознавчого музею НАН України // Наукові записки Державного природознавчого музею. – Львів, 2004. – Т.19. – С. 15-28.
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Taxonomic branch