Hydrobiologic Survey of Some Lakes of Mountain Range Ergaki (West Sayan)

Abstract

Three alpine lakes (Oiskoe, Karovoe, Raduzhnoe) of mountain range Ergaki were sampled in 11- 15 September 2008. Species (taxonomic) composition, number of species, abundance and biomass of phytoplankton and zooplankton, phytobenthos and zoobenthos of each lake were studied for the first time. Coefficients of species similarity of plankton and benthos assemblages between lakes were calculated. Results of fishing in the lake Oiskoe were presented. As found, species diversity of plankton and benthos assemblages of the lakes were low and the lowest one was in the fishless lake Karovoe. Similarity of species composition between lakes were low (0,09-0,40). Biota of the lakes in general consisted of species with widespread distribution, with the exception of some species, namely Alona werestschagini Sinev known (in Russia) from Altai and north of Europe only, and Arctodiaptomus dahuricus Borutzky known from Transbaikalia. Thus areals of these species were expanded, but Arctodiaptomus may be a new species (subspecies) Despite of the low abundance and biomass of phyto- and zooplankton (characteristic of oligotrophic lakes) and low or moderate zoobenthos biomass (characteristic of oligotrophic-mesotrophic lakes), catched individuals of fish Thymallus arcticus Pallas were fat (mark 3-4) and their guts were filled. Apparently food supply is sufficient for good fitness of the existed grayling population.

Keywords

• alpine lakes
• phytoplankton
• phytoperiphyton
• zooplankton
• zoobenthos
• ichthyofauna
• species composition
• diversity
• biomass