Volga Pikeperch
Sander volgensis (Gmelin, 1788)
Lucioperca volgensis Gmelin, 1788: Kovatcheff, 1923: 25; Drensky, 1951: 182; Stizostedion volgense (Gmelin, 1788): Sivkov, 1987: 204.
Order Perciformes
Family Percidae
Conservation status: in Bulgaria: Critically endangered CR [A1a; E]; International: IUCN [DD], BeC-III.
General distribution. The basins of the Caspian Sea, the Black Sea and the Sea of Azov, mainly inhabiting the lower reaches of bigger rivers that empty into them: Volga, Ural, Don, Dnieper, Bug, Dniester and the Danube.
Distribution and abundance in Bulgaria. In the past, the species was recorded in the Danube River from Vidin to Silistra [1, 2, 3, 4], occasionally entering the lower reaches of some of its tributaries – the Iskar and Yantra Rivers [5, 6]. It was caught also in Burgas Lake [6]. Recently, single specimens have been found only in the Danube River.
Habitats. Only permanent large rivers.
Biology. It reaches sexual maturity at the age of 3-4 years. Spawning occurs in the period April-May at water temperature of 13-15°C. Females lay their eggs on submerged plants, stones or sand. The fecundity varies from 50 000 to 1 000 000 eggs. The juveniles feed on crustaceans but also start feeding on fish as early as the very first year [7].
Similar species. In the fresh waters of Bulgaria another species of the genus Sander occurs: the pike-perch (S. lucioperca). The Volga pikeperch is differentiated by the lack of canine teeth and the shorter and rounded head.
Negative factors. Loss (degradation) of habitats as a result of river regulation activities; water pollution; overfishing and poaching.
Conservation measures taken. None.
Conservation measures needed. Development of an Action Plan for the protection of the species in Bulgaria, control of fishing in the Danube River and protection of rivers against pollution.
References. 1. Kovatcheff, 1923; 2. Drensky, 1951; 3. Marinov, 1978; 4. Sivkov, 1987; 5. Karapetkova, 1972; 6. Karapetkova, Zivkov, 1995; 7. Berg, 1949.
Authors: Tihomir Stefanov, Yanaki Sivkov, Teodora Trichkova
