Scientific publications

The anthropogenic impact on the living nature has particularly increased over the last decade. Presently, the tendency for further intensification of the process is clearly expressed. The preceding refers in full measure to aquatic ecosystems as well. Therefore, the study and conservation of biological diversity in the whole complex of natural entities, animal and plant species and populations proves to be rather timely. As applied to fishes biodiversity conservation for this group of animals becomes possible only when the whole of the aquatic ecosystem is protected.

Present condition of the ichthyofauna in a number of water bodies located in the landscape reserve "Tolvojarvsky" (Suojarvi region, Republic of Karelia): Tolvojarvi, Sarijarvi, Yula-Tolvojarvi, Ala-Tolvojarvi and Yurikkajarvi, was investigated in 1993-1995. Nine fish species were found to inhabit these lakes: European cisco Coregonus albula, pike Esox lucius, roach Rutilus rutilus, ide Leuciscus idus, dace L.leuciscus, bleak Alburnus alburnus, perch Perca fluviatilis, burbot Lota lota and sculpin Cottus gobio. As compared with the data from the previous investigations bream Abramis brama and ruff Gymnocephalus cernuus were not found in control catches. Perch, roach and cisco (except for lake Yurikkajarvi, where it was not found) are the most wide-spread fishes in all the lakes enumerated. Pike is common though not abundant. The rest of the species are met only occasionally.

The lakes examined are quite typical for this region according to the limnological indices and the species composition of the fishes living in them. These water bodies are especially valuable in that they are inhabited by large cisco. Such populations are extremely vulnerable and can easily go extinct if the anthropogenic effect grows, which has already been observed for some lakes in Karelia.