Composition and Abundance of Zooplankton in Kardzhaly Reservoir

I. TRAYKOV1, B. BOYANOVSKY1 and M. ZIVKOV2
1 Sofia University “St. Kl. Ohridski”, Dep. of Ecology and EP, Faculty of Biology, BG-1164 Sofia, Bulgaria
2 Bulgarian Academy of Sciences, Institute of Zoology, BG - 1000 Sofia, Bulgaria

Abstract

TRAYKOV, I., B. BOYANOVSKY and M. ZIVKOV, 2011. Composition and abundance of zooplankton in Kardzhaly reservoir. Bulg. J. Agric. Sci., 17: 501-511

The zooplankton community structure in “Kardzhaly” reservoir (South-East Bulgaria) was studied from July 2000 to November 2002. The seasonal cycles and population dynamics of the main taxonomic groups are described and discussed. The zooplankton community was composed of 12 species of Rotifera, 13 species of Cladocera, 7 species of Copepoda, 1 species of Ostracoda, 1 species of Cnidaria (Coelenterata), 1 species of Hydracarina and 1 species of Ciliata. The abundance of the zooplankton increases, 5 times on average, between the limnetic and the riverine zone of the reservoir. The Copepoda dominated the limnetic zone, closely followed by Cladocera, while in the transitional and the riverine zones the opposite was true. The zooplankton community was mostly crustacean, with the following perennial species: Kellicottia longispina and Keratella cochlearis from the Rotifera; Daphnia longispina, Bosmina longirostris and Bosmina coregoni from the Cladocera, as well as Cyclops vicinus, Eudiaptomus gracilis and the nauplii and copepodites of the Copepoda. Some relationships were found between the trophic state, the reservoir exploitation and the zooplankton community.

Key words: zooplankton, trophic state, seasonal dynamics, spatial heterogeneity

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