Early data on macrozoobenthos of Lake Tikshozero

The article presents the results of the assessment and inventory of the current state of the macrozoobenthos communities of Lake Tikshozero (Western Karelia), which belongs to the small water bodies of the White Sea basin. The reservoir is remote from settlements and industrial facilities, it is used for recreation purposes, popular for amateur and sport fishing. There are given the results of studying the species diversity of macrozoobenthos, structure of dominant species, ratio of the main taxonomic groups, their quantitative indicators. The Tikshozero ecosystem is under the influence of human economic activity; a commercial trout farm is located in its water area. The work was carried out to assess the current state of the benthic fauna of a little-studied reservoir, which is in conditions of a transitional trophic status. The lake is part of the largest lake-river system of the Kem River in the republic and can act as a model control object for studying the level of impact on small water bodies of the European North. Data on changes in the composition of benthic communities caused by various factors can serve as indicators of the aquatic environment. To preserve the current state of the Tikshozero ecosystem and to study the dynamics of possible changes it is necessary to conduct monitoring of the water body. Widespread indices were used to assess the degree of water quality by macrozoobenthos: chironomid index K, oligochaete index (Goodnight-Whitley), Mayer index (S). In accordance with the results obtained, the reservoir is reffered to moderately polluted water bodies. It has been established that by the level of development of macrozoobenthos and its structural and functional indicators the lake belongs to α-mesotrophic water bodies. According to the value of the Pantle–Bukk saprobity index, the water body can be attributed to the β-mesosaprobic type (moderately polluted waters)