Taxonomic Composition and Quantative Indicators of Macrozoobenthos in Water Bodies of West Kazakhstan Region

Abstract

The article presents the results of the study of macrozoobenthos communities of six lakes in the West Kazakhstan region in the summer-autumn period: Shalkar, Balykty Sarkyl, Edilsor, Glubinnoye, Prorva and Sulukol. Lakes Prorva and Sulukol are located within the steppe, the lakes Shalkar, Balykty Sarkyl, Glubinnoye - in the semi-desert, Lake Edilsor - in the desert zone. In total, 197 samples of zoobenthos were taken according to generally accepted hydrobiological methods. There are analized the indices of the number and biomass of aquatic organisms in the studied reservoirs. According to the results of the studies carried out, the organisms of 66 taxa from the groups Oligochaeta, Hirudinea, Bivalvia, Gastropoda, Crustacea, and Insecta were found in benthic samples. Of thesethere were found oligochaetes - 2 species, leeches - 1 species, bivalves and gastropods - 3 species each, crustaceans - 4 species and insects - 53 taxa. Among insects, dip-terans (23 taxa, of which chironomids - 18), mayflies, caddis flies, dragonflies, bugs and beetles were distinguished by the greatest species diversity. It was noted that in the composition of benthic communities, diptera larvae dominated in abundance, the main contribution to the biomass was made by bivalve molluscs. Calculations of the Shannon – Weaver index demonstrate a low species diversity of communities for all water bodies. The highest indices of species diversity were noted in Lake Edilsor - 1.64 bit / specimen, the lowest - in lakes Sulukol and Shalkar - 0.6 bit / specimen. and 0.7 bit / copy. respectively. According to the calculations of the saprobity index, lakes Glubinnoye, Prorva and Balykty Sarkyl belong to the ß-mesosaprobic zone, Lake Edilsor (S = 2.72) to the ɑ-mesosaprobic zone, and the indicators of Lake Sulukol (S = 3.8) correspond to the polysaprobic zone. The values of the saprobity indices of the studied lakes lie within the beta-mesosaprobic – polysaprobic zones. By water quality the studied lakes are assessed as moderately polluted and polluted. According to the classification of S.P. Kitaev (2007) the investigated water bodies are assessed as water bodies of medium feeding. The conducted studies have significantly expanded the taxonomic lists of benthic organisms in this region