“Karelian Lakes” expert system: 3. Model approach to studying fish communities

The final work on the development of an expert system for the assessment of the state and the rational use of lake’s resources is presented. A block of expert system for the assessment of ichthyocenoses is described. For this purpose, databases and knowledge bases on 12 species of most abundant Karelian fishes were used and a model of community, based on the principle of trophic chain, was proposed. The system was developed for water bodies with different compositions of ichthyocenoses and different food and abiotic conditions. The model makes it possible to assess the ichthyomasses and age structure of populations and to determine the rational ways to commercial use of the community for maximizing the catches with the preservation of biodiversity.