Characteristics of the ichthiofauna reproducing in the middle zone of the Volgograd reservoir in the water areas from 2017 to 2022

Abstract

The formation of reservoirs significantly changes all aspects of the life of various fish species, and especially the conditions for their reproduction. Creation of a new reservoir is accompanied by a change in the level and temperature regimes, which in turn leads to shifts in the ecosystem as a whole. The accumulation of significant water masses and their subsequent discharge causes a shift in the seasonal rhythm of the water runoff. With a sharp discharge of water, the spawning area is reduced, up to its complete loss, drying and death of the laid eggs. A favorable level regime, with a high parameters of spring water rise and prolonged standing of water at maximum levels, is rarely observed. For decades, the succession of the Volgograd reservoir has been observed, and at the moment it is not known what the climax point of this process will look like. All this makes it relevant to monitor the reproduction of the ichthyofauna of the reservoir as a whole and for individual water areas. This article presents the results of studies of the qualitative and quantitative composition of the ichthyofauna of the middle zone of the Volgograd reservoir in the waters near Akhmat and Zolotoye villages, Krasnoarmeisk district, Saratov region. The species composition of fish reproducing in the indicated water areas for a six-year period (from 2017 to 2022) and their number in the catches of fry net by years are shown. Dominant, subdominant and specific for each water area species were identified. The fluctuation of species diversity (Shannon index) and the dependence of the state of this indicator on the abundance of individual fish species were studied. The dynamics of the ratio of underyearlings of commercial and non-commercial fish species in catches is considered. Ichthyofauna, reproduced in the waters near the villages Akhmat and Zolotoye in the middle zone of Volgograd reservoir in the period from 2017 to 2022 represented by 21 species of various fish, of which 17 species breed in the water area near Akhmat village and 18 species breed in the water area near Zolotoye village.