Knipowitschia longecaudata (Kessler, 1877)
Gobius longecaudatus Kessler, 1877: Drensky, 1923: 97.
Conservation status: in Bulgaria: Critically endangered CR [B 1a; E].
General distribution. A Ponto-Caspian relict species. Common in the western and the northwestern part of the Black Sea and in the eastern part of the Sea of Azov and the Caspian Sea.
Distribution and abundance in Bulgaria. Initially, the species range in Bulgaria was considered as much bigger, comprising the brackish waters in the bays with sandy bottom around Varna, Burgas and Sozopol [1, 2]. Later, it was found out that along the Bulgarian coast, the long-tailed goby occurred only in Beloslav Lake [3, 4]. After Beloslav Lake had been connected with Varna Bay, it lost its natural fauna, so the species was considered extinct in the fauna of Bulgaria . In 1998, it was recorded again in Shabla Lake .
Habitats. Coastal fresh water and brackish lakes, sea shallows up to 6 meters deep, sea bays.
Biology. It reaches sexual maturity in the first year. Females spawn repeatedly from March to late July. Eggs are deposited underside of bivalve shells or stones. The fecundity ranges from 500 to 1 500 eggs. It feeds on small crustaceans, insect larvae and worms [3, 7].
Similar species. Another species of the same genus is found in Bulgaria – Knipowitschia caucasica. K. longecaudata is differentiated by its longer and slender caudal peduncle and the nonsymmetric caudal fin.
Negative factors. Loss and degradation of habitats; water pollution.
Conservation measures taken. The species was listed in the Red Data Book of Bulgaria (1985) and the Red Book of the Black Sea (1999). The only habitat where the species was found is included within the Shabla Lake Protected Area.
Conservation measures needed. Control of observing fishing regulations in the Shabla Lake Protected Area.
References. 1. Drensky, 1923; 2. Drensky, 1951; 3. Stojanov et al., 1963; 4. Gheorghiev, 1966; 5. Botev, Peshev, 1985; 6. Vassilev, 1998; 7. Miller, 1986.
Authors: Tihomir Stefanov, Teodora Trichkova, Yanaki Sivkov