Biological Indicators of Water Quality of Drenova Reservoir (Bosnia and Herzegovina)¹

This paper presents the state of biota of Drenova reservoir in Bosnia and Herzegovina (B&H) as water quality indicator. The Drenova reservoir has a multiple role: protection of the Vijaka river basin from floods, provision of water for the Prnjavor fishpond, as well as sport fishing. Bearing in mind the multifunctionality of this reservoir, but also the scarcity of data on the biota of this water body, in 2017, research on phytoplankton, zooplankton, macrozoobenthos and ichthyofauna was performed. Based on the obtained results (qualitative and quantitative composition, saprobic index according to Pantle Buck, Shannon index), it was established that the water of Drenova reservoir, as far as phytoplankton and zooplankton community is concerned, corres-ponds to the transition from oligosaprobic to β-mesosaprobic waters while macrozoobenthos and ichthyofauna refer to β-mesosaprobic water. A small number of representatives of phytoplankton (both qualitatively and quantitatively) is noticeable, as well as the absence of species common to this type of aquatic ecosystems in the observed period. The state of macrozoobenthos taxa is expected considering the properties of the substrate of this accumulation. Ichthyocenosis is characterized by a small number of species, but also by a small number of individuals within those species.