Acipenseridae

4.2 | Acipenseridae View in CoL View at ENA

The actual distribution of sturgeons in the study area is not well understood. Acipenser sturio and A. nudiventris have vanished from the Caucasus since no records for decades exists. Even whether other sturgeon species still spawn regularly in the Kura and Rioni rivers, is doubtful. Acipenser colchicus was considered the Black Sea population of the Persian sturgeon ( Acipenser persicus ) by Marti (1940) or even the eastern Black Sea population of the Russian sturgeon A. gueldenstaedti by Berg (1949). It has been accepted as a valid and the Black Sea endemic species by Kottelat and Freyhof (2007). Following Marti (1940) we identify A. colchicus as the Black Sea population of A. persicus until the separate species status is confirmed.

Acipenser ruthenus has been recorded from the Kura River drainage in Azerbaijan and Berg (1949) mentions occasional findings from the western Caspian coast and the lower Kura River. However, there is no record or indication that there had ever been an established population of this species in the area. It is suspected, that sterlets found in the Kura mouth were migrants from the Volga population. The anadromous sterlet population in the Volga has vanished in the 20th century ( Kottelat & Freyhof, 2007) and more recent records of sterlets are very likely to have come from fish farms. It should be mentioned that, apart from anadromous populations, there are resident populations within the Volga drainage, for instance the Oka and Sura Rivers populations ( Ivancheva & Ivanchev, 2008; Shilin, 2001).