We studied predatory fish species in relation to the biodiversity of fish assemblages and environmental variables at 511 sites in small and mid-sized rivers at the eastern edge of the European continent. The studied region has a high geographical and environmental heterogeneity. The impact of environmental factors on species occurrence was analyzed with generalized linear models. The main influential environmental factors on the occurrence of predatory fish species were elevation and the width and depth of the river. For the first time for a large area of Eastern Europe, optimum points and niche breadths for predatory fish species along width, depth, and velocity gradients were estimated. The width of the ecological niche can vary significantly both between different species of fish and within the same species for certain factors. Our results identify the bioindicative potential of predatory fish species in river ecosystems in this, sometimes overlooked, the eastern part of the continent. We found that the probabilities of occurrence of pike, burbot, pikeperch, and asp were close to zero when the Shannon index was less than 1 and the number of fish species was less than 5. The probability of occurrences of perch was 100% if the number of fish species in the site was more than 15.

我们在欧洲大陆东部边缘的中小河流的 511 个地点研究了与鱼类组合和环境变量的生物多样性有关的掠食性鱼类物种。研究区域具有较高的地理和环境异质性。采用广义线性模型分析环境因素对物种发生的影响。影响掠食性鱼类发生的主要环境因素是海拔和河流的宽度和深度。首次对东欧的大面积区域的掠食性鱼类沿宽度、深度和速度梯度的最佳点和生态位宽度进行了估计。由于某些因素，生态位的宽度在不同鱼类之间和同一物种内可能存在显着差异。我们的研究结果确定了该大陆东部有时被忽视的河流生态系统中掠食性鱼类的生物指示潜力。我们发现，当香农指数小于 1 且鱼类种类数小于 5 时，梭子鱼、江豚、梭鲈和 asp 的发生概率接近于零。该地点的鱼类数量超过15种。