Scientific publications

The article discusses the topical issue of assessing the dynamics of biological diversity through the case study of commercial fish populations of Lake Ladoga. Changes in the structure of fish community in the lake were traced using fishery statistics for the period 1946–2023. For the mathematical and statistical analysis, the primary dataset on industrial fish catches was divided into five-year periods, excluding the period 2016–2023 period. Despite the selectivity of harvesting, the structure of catches in long-term observation series quite adequately reflects the dynamics of the fish population and changes in its species diversity, represented by the catch composition and the biomass ratio of different fish species. However, the reliability of the assessment of the declining diversity trend is questionable when using different biodiversity indices. The purpose of this study was to comparatively analyze the performance of different biodiversity indices in assessing the dynamics of the species diversity of the fish population of Lake Ladoga. The following six indices were used: Shannon index (H), Pielou index (E), Sheldon index (SH), Zhivotovsky index (μ), Simpson’s dominance (C) and diversity (D) indices. The matrix of pairwise correlations of biodiversity indices used to assess structural changes in the species diversity of the fish population of Lake Ladoga is presented. The Sheldon and Shannon indices were found to be the most informative. From 1960 to 2023, the Sheldon biodiversity index increased from 13.3 to 13.6, showing a high negative trend (correlation coefficient r = 0.74 on the Chaddock scale).