ASSESSMENT OF THE CURRENT STATE OF BENTHIC FAUNA AND WATER QUALITY OF CHANNELS OF THE VOLGA DELTA

Abstract

Aim. We present the findings of studies of the current state of benthic fauna of the Volga delta channels by the structure of benthic communities. The study has been carried out in the framework of researches by FSBSI "Caspian Fisheries Research Institute" conducted in the period from 2010 to 2014. The main goal was to assess the current state of benthic fauna of output channels of the Volga delta areas against the backdrop of changing water availability of the Volga river. Methods. We have conducted sample processing of zoobenthos within investigated watercourses of the Volga River according to conventional methods of Zhadin V.I. (1960), Winberg G.G. (1984) and Abakumov V.A. (1992). Results. The results of the work on the study of the modern state of the benthic fauna of the Volga delta channels show that the species composition of macrozoobenthos in these sections of the river in dry years was characterized by mass development of oligochaetes. With the increase of water content (between the years 2012 and 2013) in all studied water streams there is a change of the dominant group. With the decrease in the annual runoff (in 2014) the qualitative characteristics of zoobenthos have changed. In the average long-term aspect, the distribution pattern of quantitative indicators of benthic invertebrates in the delta of Volga river was uneven, and their greatest density has been marked in the wet year. Main conclusions. Thus, the research found that increase of the water content of the Volga River positively influences the hydrobiological picture in the output channels of the delta of the Volga River.