CURRENT STATE OF COMMERICAL ICHTHYOFAUNA OF THE DNIPRODZERZHINSK RESERVOIR

Purpose. Evaluation of structural‐biological indices, which characterize the state of the Dniprodzerzhinsk reservoir from the point of view of conditions of formation and exploitation of commercial fish stocks. Methodology. Field data were collected during 2013 using a standard set of control fishing gears (gill nets with mesh size a = 30 ? 120 mm). Processing of ichthyological materials was conducted according to methods generally accepted for the Dnieper reservoirs. In total, 148 net‐days of control gill nets were analyzed, of which 1051 fish were selected. Findings. Structural indices of the Dniprodzerzhinsk reservoir biocenoses was characterized by certain stability, the basis of ichthyofauna (46,6 % of the general ichthyofauna) is formed by bream represented in catches primarily by age‐6 ? 9 fish, i.e. the modal range of this species remains stable. A negative trend of shortening of elder age groups is observed for roach that resulted in a decrease of weighted average age to 4,6 years. Similar trend is also observed for pike‐perch, however, high indices of catches of mean age groups indicate on entrance of abundant generations to the reproductive core. Total ichthyomass of commercial fish species (without taking into account Black Sea sprat) in 2013 can be estimated as 70,4 kg/ha. Originality. For the first time during last 20 years, general description of the Dniprodzerzhinsk reservoir ichthyofauna has been presented and main qualitative and quantitative indices, which determined conditions of formation and exploitation of commercial fish stocks, have been analyzed. Practical value. Results of this work have been used for determination of allowed amounts of commercial catch in the Dniprodzerzhinsk reservoir.