Modern characteristics of mass fish species and their parasites in polar reservoirs of the Yenisei basin (on the example of Kureyskoye)

Abstract

The results of ichthyological and parasitological studies of the Kureiskoye reservoir are presented. The features of the formation of ichthyofauna during the formation of a reservoir and its industrial use are shown. The ichthyofauna of the Kureiskoye reservoir was formed on the basis of the indigenous fauna of the river. Kureyki. The modern composition of fish includes 22 species. Grayling fish are represented only by the Siberian grayling — Thymallus arcticus (Pallas, 1776). This species has a relatively small number of scales in the lateral line (no more than 95). Grayling is found in Lake Munduyskoye, which on average has about 100 scales. Since Munduyskoye Lake belongs to the river basin Kureyka, we believe that the second species, the black Baikal grayling Th. baicalensis (Dybowski, 1874) is also present. The main processes of its formation took place as in the Khantaskoye reservoir. Currently, the number of salmon and whitefish is decreasing. These groups of fish previously formed the basis of the composition of the original ichthyofauna. Today salmon and whitefish are found in the zone of backwater and flooded tributaries of river channels. The composition and number of whitefishes has changed especially. Tugun practically disappeared, others (peled, wild boil, vendace, and whitefish) began to be found singularly. The dominant role is played by pike, which uses peat islands for its spawning, as well as perch and roach. The transformation of the reservoir led to radical changes in the composition and structure of communities of all groups of organisms in the aquatic biota. This influenced the composition and abundance of fish parasites. The parasite fauna of the fish of the Kureyskoye reservoir is represented by widespread species of helminths. Infection with helminths mainly occurs when fish feed on planktonic crustaceans.