Three-Spined Stickleback
Gasterosteus aculeatus Linnaeus, 1758
Order Gasterosteiformes
Family Gasterosteidae
Conservation status: in Bulgaria: Vulnerable VU [A3]; International: IUCN [LR/lc].
General distribution. It inhabits the northern parts of the Atlantic and the Pacific Oceans: in Europe – from Novaya Zemlya Islands, the White Sea, Kolsk Peninsula and Iceland, to Algeria and the Black Sea; the Baltic Sea; from Greenland to New York; in the Pacific Ocean – from the Bering Strait to Korea and Japan, the Kurile Islands, along the American coast as far south as California.
Distribution and abundance in Bulgaria. In the past, along the entire Black Sea coast, mainly in the limans, the mouths of the rivers and the coastal lakes, as well as the marshes along the Danube [1, 2, 3, 4, 5]. It has been recorded in the lakes Varna, Beloslav, Burgas (Vaya) and Mandra [6], and in most Black Sea rivers (3, 4, 7, 8, 9). Recently, the species has been found near Kaliakra [10], in Varna Bay [11], Durankulak Lake [12], the rivers Ropotamo [13], Marinka, Otmanliy, Karaagach, Arapya, Popska, Izgrevsko Dere, Varvara, Butamyata and Silistar [14], as well as in the rivers Kamchiya and Danube [our data]. The presence of the species in the Veleka River has not been confirmed [15].
Habitats. The main habitats of the species are open sea, sea shallows (up to a depth of 6 m, including sea bays), coastal brackish and saline lagoons, permanent rivers and marshes.
Biology. It reaches sexual maturity at the age of 1–2 years. Spawning occurs in April–June at water temperature of 16-24 °C. During the spawning period, males attain a breeding colouration and build nests from plant fragments. The females lay from 500 to 2 000 eggs. The males guard the nests until the eggs hatch. It feeds on crustaceans, worms, insect larvae, fish eggs and small fish [5, 16, 17].
Similar species. The southern ninespine stickleback (Pungitius platygaster). The three-spined stickleback is distinguished by the lower number of dorsal fin spines (2-3), complete row of side bony plates, a well-developed caudal peduncle keel, and higher body length (9-10 cm).
Negative factors. The main threats to the species are the loss of habitats, as a result of draining of marshes and backwaters along the Danube River, as well as the wetlands along the Black Sea coast; tourism and recreation development; water pollution.
Conservation measures taken. The species was listed in the Red Data Book of Bulgaria (1985).
Conservation measures needed. Development and implementation of an Action Plan for the protection of the species in Bulgaria. Restoration of the wetlands along the Danube and protection of the species habitats against pollution.
References. 1. Kovatcheff, 1923; 2. Drensky, 1923; 3. Drensky, 1948; 4. Drensky, 1951; 5. Stojanov et al., 1963; 6. Gheorghiev, 1967; 7. Pechev, 1969; 8. Pechev, 1970; 9. Karapetkova, 1976; 10. Sivkov, 2000; 11. Sivkov, 2003; 12. Sivkov, Sivkova, 2003; 13. Pehlivanov, 1999; 14. Trichkova et al., 2006; 15. Karapetkova et al., 2003; 16. Svetovidov, 1964; 17. Banister, 1986.
Authors: Yanaki Sivkov, Teodora Trichkova, Tihomir Stefanov
