Zooplankton of the Kama river, the fauna composition and structure, the assessment of the ecological state of the environment

Abstract

The paper deals with the study of zooplankton in the lower stream of the Kama river, the largest tributary of the Volga, which has important economic importance for the European part of Russia. The obtained results allowed to establish the summer composition of zooplankton fauna of the studied reservoir, to determine the quantitative characteristics of the communities. 61 taxa belonging to 3 types were identified: Rotifera, Arthropoda (Cladocera, Copepoda groups) and Mollusca (Bivalvia). The average species density in the study area is 10 1 taxa per station. The average biomass in the study area was 0,679 0,434 g/m, the average number was 49,50 8,01 thousand specimens/m. The average daily zooplankton production was 0,043 0,020 g/m. The biocenotic analysis has allowed to allocate five types of communities with the dominance of the major species of rotifers, cladocerans and copepods in the study area. The two-factor analysis showed that the structure of communities is more influenced by the local features of biotopes than the general conditions at the study sites. The wellbeing index indicates that the communities of zooplankters in the lower stream of the Kama river are in a state of near stress. The environmental assessment on the composition and structure of types of indicators is possible to attribute this body of water to moderately polluted water (-mezosaprobic zone).