Influence of environmental conditions on the heart index Thymallus arcticus of the Kazyr river (r. Yenisey basin)

The article considers the results of studies of the morphophysiological index of the heart of Thymallus arcticus, which was caught in the Kazyr River (Krasnoyarsk Territory) in the summer period (August) 2020. An analysis of the heart index (morphophysiological indicator) is also presented. Attention is paid to the dependence of the value of the indicator on the state of the environment, assessment of the quality of the river. The information and the location are new to research.