Biological parameters and morphological characteristics of the perch (Perca fluviatilis Linnaeus, 1758) of the central part of the Kuibyshev reservoir
This article presents the size and age composition of the perch population from the three central reaches of the Kuybyshev reservoir, based on net catches from 2014 to 2018, and also compares the results with the data of research works. The maximum specimen of perch, caught in the Volga-Kama Reach of the Kuibyshev Reservoir over the years of research, had a body length of 40 cm, weight over 1.5 kg and an age of 13 years. The influence of the habitat on aquatic biological resources has been investigated. Methodological approaches to the study of the variability of the assimilative coloration of a perch body have been presented. The article describes the main phenotypes of river perch of the central reaches of the Kuybyshev reservoir, as well as shows the dependence of the variety of perch body color on its living conditions. In the studied areas of the Kuibyshev reservoir, 15 types of river perch colorings were recorded from 28 previously registered in the range by other researchers. The most common phenotypes of striated pigmentation (РPP) of the perch body of the studied areas of the Kuibyshev reservoir were identified. Modal values were calculated, as well as the average seasonal pigmentation index of river perch fen. Cluster analysis showed a similarity of fens in the samples of the Volga and Volga-Kama reaches, most similar in terms of habitat. A morphometric analysis of the river bass body was performed. Data on the main meristic and plastic morphological features of river perch are presented. The morphological characteristics of males and females of river perch were compared: morphological gender differences were found only in the spawning period.