Structural indices of the European perch (Perca fluviatilis Linnaeus, 1758) population in the Kremenchuk reservoir

Objective. Analysis of the structural parameters of the perch (Perca fluviatilis L.) population in the Kremenchuk Reservoir in the world of the development of the program of stocking large flat reservoirs of the Dnipro with juveniles of Far Eastern herbivorous fish, there was a need for methodical approaches to reduce the negative impact of small predators on the efficiency of planned stocking. Methodology. Primary materials related to the biology and fishing of perch were collected at the monitoring points of the Institute of Fisheries of the National Academy of Sciences. The basis of this article is the results of our own field research, which was carried out in the entire water area of the Kremenchuk Reservoir during 2016–2021. To determine the composition of catches in nets with different mesh sizes, the refined coefficient of annual commercial mortality was used. Results. The article establishes the general basic population indices of the perch (Perca fluviatilis L.) population in the Kremenchuk Reservoir. Acceptable indices of the perch population and the probability of its negative impact on the stocking of big-headed Chinese carps this year have been established. The scientific novelty of the work is due to the fact that effective stocking is currently possible only in the presence of scientifically based data, which can significantly affect the cost of planting material, and, as a result, the volume of work carried out. These basic principles are able to ensure the sustainable use of aquatic biological resources in natural reservoirs. Practical significance: the biological indices of the P. fluviatilis population presented in this work can be used to calculate the limits for perch commercial fishing in Kremenchuk Reservoir and to assess its negative impact on the stocked young fishes. Key words: perch, Kremenchuk Reservoir, length structure, catch per unit effort, commercial harvest.