Caspian Shad
Alosa caspia (Eichwald, 1838)
Alosa nordmanni Antipa, 1906: Kovatcheff, 1922: 108; Alosa caspia nordmanni (Antipa, 1906): Vassilev, Pehlivanov, 2005: 163; Alosa bulgarica Drensky, 1934: Drensky, 1934: 79-87; Alosa caspia bulgarica (Drensky, 1934): Vassilev, Pehlivanov, 2005: 163.
Order Clupeiformes
Family Clupeidae
Conservation status: in Bulgaria: Vulnerable VU [A1c], BDA-II, IV; International: HD-II, V.
General distribution. It inhabits the Black Sea, the Sea of Azov and the Caspian Sea, from where it enters the rivers and the coastal lakes for spawning.
Distribution and abundance in Bulgaria. In the past it was a common species for the Bulgarian Black Sea coast. It was found in the rivers Kamchiya, Ropotamo, Veleka and Rezovska [1, 2, 3, 4, 5, 6] and the lakes Varna and Beloslav [7]. In the Kamchiya River, it was found at about 100 km upstream from the mouth [4]. It enters occasionally the Bulgarian section of the Danube River [8, 9, 10]. In recent years it has been recorded in Varna Bay [11] and in the Ropotamo River [12]. Its occurrence in the Veleka River has not been confirmed [13, 14].
Habitats. The main habitats of the species are open sea and permanent rivers. It is also found in sea shallows at depths of up to 10 m, including sea bays.
Biology. It reaches sexual maturity at the age of 2 years. Spawning occurs during April–June at water temperature of 14-24°C, and at depths of 1.5–4.0 m. The fecundity of females ranges from 10 300 to 88 200 eggs. The development of the eggs takes place at the bottom [10, 15]. It feeds on insect larvae, crustaceans, worms, fish eggs and fish [16].
Similar species. Another two species of the genus Alosa – the Pontic shad (Alosa pontica) and the Black Sea shad (A. maeotica) are known along the Bulgarian Black Sea coast. The Caspian shad differs from them by the higher number of gill rakers (62-98) and the smaller sizes (body length less than 20 cm).
Negative factors. Industrial pollution of water and overfishing.
Conservation measures taken. The species was listed in the Red Data Book of Bulgaria (1985) and in Annexes II and IV of the Biological Diversity Act (2002).
Conservation measures needed. Protection of the habitats of the species against pollution and strict control of observing the fishing regulations.
References. 1. Kovatcheff, 1923; 2. Drensky, 1934; 3. Karapetkova, Pechev, 1973; 4. Karapetkova, 1974; 5. Karapetkova, 1975; 6. Karapetkova, 1976; 7. Gheorghiev, 1967; 8. Drensky, 1948; 9. Drensky, 1951; 10. Stojanov et al., 1963; 11. Sivkov, 2003; 12. Pehlivanov, 1999; 13. Karapetkova et al., 2003; 14. Trichkova et al., 2006; 15. Karapetkova, 1991; 16. Svetovidov, 1964.
Authors: Yanaki Sivkov, Teodora Trichkova
