Algae and Invertebrates of the Chikoy River and its Tributaries

The Chikoy is a taiga river of the Lake Baikal basin, the biggest tributary of the Selenga River. It is slightly developed and is characterized by the intact state of the natural complexes. The article presents the data on the features of the plankton qualitative and quantitative development in the river middle range and its tributaries such as the Kunaley, the Ashgaley, the Cheryomushka, the Goryachaya, the Solontsovaya and the Bolshaya Burecha (Transbaikal Kray). However, data on the river plankton, available today, are insufficient and fragmented. Studies conducted in May and July 2017 made it possible to establish that the taxonomic composition of the plankton in some tributaries of the Chikoy River (middle course) is extremely poor and is represented by 57 taxa below the genus (34 algae and 23 invertebrates). Diatom algae (up to 80%) and rotifers (up to 60%) dominated in species richness. Species Fragilaria capucina, Gomphonema lanceolatum, Diatoma vulgaris, D. vulgaris var. producta, Hannaea arcus, Ulnaria ulna were dominants in phytoplankton. The algological composition and its dominant forms in the studied rivers were similarity. In the zooplankton, a single complex of dominant species, characteristic of all watercourses, has not been identified. The taxonomic composition and abundance of invertebrates were very poor. In the course of the work carried out, it was established that, despite the geographical position and mountain character of the river, the share of cold-loving species in plankton does not exceed 10.5% – for algae and 7% – for zooplankton. The poor species composition and density of plankton algae and invertebrates correspond to the oligotrophic type of watercourses. The obtained data are primary and can be used for further biological monitoring of the watercourse related to the Baikal basin.