Abstract
This is the first description of chrysophycean stomatocysts in Boguchany Reservoir after its impoundment and the launch of a new hydropower plant on the Angara River, which has its headwaters in Lake Baikal. Thirty-five morphotypes of the stomatocysts were found, 10 of them were registered in Russia for the first time and nine morphotypes new to science are described. The list of chrysophycean stomatocyst morphotypes of the Baikal Region was expanded to 203 morphotypes. Hydrochemical indicators of the sampling site are given. The data obtained can be further used as an indicator of changes in the status of the reservoir.