Current state of the forage base of section of the Dnieper river within the Smolensk region

Abstract

The paper presents materials on the state of aquatic bioresources and their habitat in the Dnieper River within the borders of the Smolensk region, according to 2019 data. The ichthyofauna of the Dnieper River within the surveyed area did not differ in species diversity: 10 species of fish belonging to the families Cyprinidae (Cyprinidae) and perch (Percidae) were identified. Roach (Rutilus rutilus) dominated, the subdominants were chub (Squalius cephalus) and perch (Perca fluviatilis). The average oligochaete index, ranging from 21 to 50%, characterizes the waters of the river as slightly polluted and belonging to class II quality. The composition of phytoplankton was dominated by diatoms and green algae. As part of zooplankton, representatives of the genus Brachionus dominated among rotifers, and crustaceans of the genus Bosmina dominated among branchiformes. The composition of zoobenthos was dominated by larvae of chironomids, subdominants – oligochaetes. The Dnieper River within the borders of the Smolensk region, according to our data, is characterized by the level of development of phytoplankton and zooplankton as a "low-feeding" area for phytophagous fish and zooplanktophages, and by the level of development of zoobenthos as a "high-feeding" area. The ichthyofauna of the studied area is characterized by the presence of predatory and omnivorous fish, the presence of phytophages and zooplanktophages is not characteristic, which may be due to the peculiarities of the state of the natural food supply.