Black Sea Salmon
Salmo labrax Pallas, 1814
Salmo trutta pallassi Gunther, 1866: Drensky, 1923: 71; Salmo trutta labrax Pallas, 1814: Drensky, 1948: 21, 1951: 54;Karapetkova, Zivkov, 1995: 94.
Order Salmoniformes
Family Salmonidae
Conservation status: in Bulgaria: Critically endangered CR [A4; C2a].
General distribution. In the Black Sea and the Sea of Azov, as well as the larger rivers that empty into them.
Distribution and abundance in Bulgaria. A rare species in the Bulgarian aquatory of the Black Sea. In the past, it was caught along the Black Sea coast from Varna to Sozopol [1, 2, 3]. It migrated into the Danube River for spawning [4], and was found near Silistra [5]. There is no information about the current state of its population. There are data that the species was recorded in the Black Sea near Varna, Nesebar and Sozopol, as well as in the Danube River [4], but it probably declined sharply in numbers. Recently, single specimens have been caught in the Danube River near Ruse [6].
Habitats. It is found in the open sea and in estuaries; it enters permanent large rivers for spawning.
Biology. It has two forms: anadromous and resident. The anadromous form is found along the entire shelf zone of the Black Sea and part of the Sea of Azov and enters the rivers for spawning. The migration of the adult individuals begins in April-May, and the spawning period lasts from the middle of October to January. The fecundity of females ranges from 2 500 to 15 500 eggs. The hatching of larvae takes place at water temperature of about 9-10 °C in the period from the middle of December to February. The migration of juveniles to the sea occurs in the autumn, before reaching 2 years of age. It reaches sexual maturity in the third year at a body length of 35-90 cm. The juvenile salmon in the rivers feed on invertebrate animals until the ages of 13-14 months, while the adults in the sea feed on fish, mainly anchovy [7].
Similar species. The Danube salmon (Hucho hucho), from which it differs by the lower number of scales in the lateral line (less than 150) and the shorter base of the adipose fin: less than 40% of the caudal peduncle length, whereas with H. hucho,it is between 49% and 90%.
Negative factors. Loss (degradation) of habitats, because of river regulation by dams and weirs; water pollution; competition with non-indigenous fish species; overfishing and poaching.
Conservation measures taken. None.
Conservation measures needed. Imposition of a total moratorium on trout fishery in the Danube River and the Black Sea.
References. 1. Drensky, 1923; 2. Drensky, 1948; 3. Drensky, 1951; 4. Karapetkova, Zivkov, 1995; 5. Marinov, 1978; 6. Vassilev, Trichkova, 2007; 7. Svetovidov, 1964.
Authors: Tihomir Stefanov, Teodora Trichkova
