Scientific publications

The mode of life of the roach Rutilus rutilus(L.) in lakes of various types in the Kenti River system, White Sea basin, Republic of Karelia, is discussed. Its biological indi-ces in the Kostomuksha tailings dump and lakes Okunevoye and Koivas were studied for the first time. These water bodies are affected by process water from the mining and ore concentration plant (MCP) built in 1982. Some specific features of the MCP im-pact on the lakes has been shown. The lake water has high dissolved solids content (up to 600 mg/l), with рн shifting towards alkalies from 6.5 to 8.4. These characteristics tells on the biological parameters of the fish fauna, including roach. Roach displayed no vi-sual changes in its external morphology or internal organs structure. However, bioche-mical and histological analyses have revealed some changes. The survival and breeding of roach in water bodies affected by human impact testify to its high adaptation potential even in an unfavorable environment. The results obtained were compared with the litera-ture on roach from other water bodies of the region. A higher growth rate, characteristic of roach from large and medium-sized lakes such as Ladoga, Onega and Syamozero, is due to their abundant foraging resources and extensive feeding and growing areas. It has been noted that roach is of minor value for industrial fisheries, but plays an important role in amateur fishing. Since roach is a strong competitor for foraging resources for valuable commercial fish species, its harvesting from Karelia’s water bodies should be increased.