Abstract
The Tobol River, a nationally significant economic water body, serves various purposes and spans across diverse landscape zones and environmental conditions.An evaluation of the forage base development of the Tobol River was conducted through the survey of six stations along the river in 2019.The investigation revealed a total of 15 species of planktonic invertebrates, including 6 rotifers, 5 cladocerans, and 4 copepods, as well as 28 species of benthic organisms.The survey period of 2016-2019 registered 36 species and forms of benthic organisms within the Tobol River basin, with a high diversity of insect groups.The considerable length and varied landscape zones of the river contribute to the observed high diversity of organisms.In terms of zooplankton development, the Tobol River exhibits a moderate food supply class and, according to S.P. Kitayev's trophic scale, can be classified as a β-mesotrophic water body.Similarly, the river's zoobenthos development indicates a moderate food supply class, designating it as an αmesotrophic type under S.P. Kitayev's trophic classification.The study of the food spectrum of river perch and roach in the Tobol River suggests relatively high food availability for these species, underscoring the importance of understanding the ecological and biological forage base of the river for maintaining ecosystem health.