Ballerus sapa

Common name. Zobel.

Diagnosis. Distinguished from Abramis, Acanthobrama, Blicca, and Vimba by: ○ mouth small, inferior / ● 47–54 total lateral line scales / ● eye large, about equal to snout length / ● 34–41½ branched anal rays. Size up to 330 mm SL.

Distribution. Kura and Aras drainages in Azerbaijan and Georgia. Aral basin and European parts of Black, Azov, and Caspian basins. Introduced or native in northern Dvina drainage (White Sea basin), where it is spreading northwards from warmer upper reaches (Vychegda system). Non-native in Volkhov (a tributary of Lake Ladoga), Rhine, and Vistula drainages.

Habitat. Large lowland rivers and estuaries. Spawns in fast-flowing water on gravel bottom or submerged vegetation.

Biology. A rheophile, nocturnal species. First spawns at 3–4 years. Spawns April–May when temperature rises above 8°C, in large aggregations. Semi-anadromous populations feed in large brackish water habitats in estuaries around Black and Caspian Seas. Spawning migration of semi-anadromous individuals begins in November (Kura). Feeds on benthic invertebrates.

Conservation status. LC.

Remarks. Often listed for Iran but has yet to be confirmed. Very rare in Kura and Aras.

Further reading. Berg 1949b (biology); Bănărescu 1964 (biology); Kottelat & Freyhof 2007 (distribution, biology, diagnosis).