IMPACT OF FISH RESOURCES MANAGEMENT ACTIVITIES ON THE FISH COMMUNITY STRUCTURE IN THE DOSPAT RESERVOIR (BULGARIA)

M. Georgieva, E. Uzunova, T. Hubenova

Abstract: The current study was initiated to gather baseline scientific information on the biological characteristics and general status of fish resources in the Dospat Dam Lake, with an emphasis on key harvested species. The main purpose of this dam is producing hydroelectric energy, but the reservoir also contains one of the biggest cage aquaculture facilities in Bulgaria. Stocking activities with different species (Coregonus peled, Onchorhinchus mykiss and Cyprinus carpio) have been conducted over the years. The fish composition observed in this investigation was compared with those from previous studies to outline the main
changes in fish composition during the period from the dam’s construction to nowadays. A total of 468 specimens were caught by gillnets and trap nets. Fish were collected from May 2009 to November 2011. Eleven fish species, belonging to five families (Cyprinidae, Cobitidae, Salmonidae, Percidae and Centrarhidae), were found. Three of them are exotic (Pseudorasbora parva, Lepomis gibbosus and O. mykiss). Three fish species are new in comparison to those reported previously (P. parva, L. gibbosus, and Zander lucioperca).A significant change was observed in the dominant fish species over the years. At present, Rutilus rutilus and Perca fl uviatilis predominate in the catches. In the littoral zones, pumpkinseeds were the most abundant species. The dominant species Barbus cyclolepis in the past was not found. Biological data (size length frequencies and age distribution) are reported for the dominant fish species.

Keywords: Bulgaria; Dam Dospat; dominant fish; species composition

Date published: 2017-09-28