NEW DATA ON RANGE EXPANSION OF ROUND GOBY NEOGOBIUS MELANOSTOMUS (PISCES: GOBIDAE) IN THE BULGARIAN TRIBUTARIES OF LOWER DANUBE RIVER
DIMITRIY DASHINOV1*, IVAN TRAYKOV2, ELIZA UZUNOVA1, LUBOMIR KENDEROV1, APOSTOL APOSTOLOU3
1 Sofia University ‘St. Kliment Ohridski’, Faculty of Biology, Department of General and Applied Hydrobiology, 8 Dragan Tsankov Blvd., Sofia 1640, Bulgaria;
2 Sofia University ‘St. Kliment Ohridski’, Faculty of Biology, Department of Ecology and Environmental Protection
3 Institute of Biodiversity and Ecosystem Research, Bulgaria Academy of Science, 2 Gagarin str., 1113 Sofia, Bulgaria
*Corresponding author: e-mail: ddashinov@abv.bg
Keywords: Neogobius melanostomus, range expansion, Danube tributaries, Bulgaria
Abstract: The round goby Neogobius melanostomus (Pallas, 1814) is a fish species native to the Ponto-Caspian region and invasive for most of European rivers, performing rapid expansions upstream of the Danube River. The aim of the current study was to investigate the distribution of the species in Bulgarian tributaries of the Danube River. A total of 12 rivers were surveyed. Fish presence was detected by electrofishing.
The present study found that within five years the round goby had expanded its range in upstream direction with 9 km in Vit River, 28 km in Iskar River and 43 km in Yantra River. For the first time the species was found in the rivers Osam and Rositsa. Large obstructions, such as HPPs and dams seem to be the main limiting factor of round goby’s upstream expansion.