Abstract—Plankton and benthos production were estimated on the basis of materials collected in the Tayshir
Reservoir after its formation. The species ratio and the growth and diets of fish have been considered also. A
high abundance and increased maximal sizes of Potanin’s Altai osman (Oreoleuciscus potanini) were revealed.
The benthic organisms dominated in the food of all three fish species inhabiting the Tayshir Reservoir: Potanin’s
Altai osman, Mongolian grayling (Thymallus brevirostris), and Siberian stone loach (Orthrias barbatulus
toni).
