Feeding and trophic interactions of plankton Crustaceans in the pelagic zone of the Azabachye Lake

Abstract

Characteristics of feeding mechanisms, forage composition and methods of analysis of the diet of plankton crustacean are demonstrated based on reviewed and author’s data. Preferable forage species for the mass plankton crustaceans Cyclops scutifer and Daphnia galeata in the lake Azabachye were figured out using methods of population ecology. It is revealed, that reproduction of the cyclops and daphnia populations prospers due to Aulacoseira subarctica. In the periods of poor vegetation of the diatom the cyclops have been feeding on shell-less rotifers, and in particular years – on the diatoms of the genera Stephanodiscus. In the years of vigorous bloom of Bacillariophyta the daphnias filter small cells of diatom (S. minutulus) or blue-green (Gloeocapsa sp.) algae. In case of suggested similarity in the forage organisms between small numbered Eurytemora kurenkovi and abundant C. scutifer, there was no competition observed between the copepods. The main forage component for predator Leptodora kindti was juvenile D. galeata. It is concluded based on the analysis, that intense competition between plankton crustaceans does not raise in the Azabachye Lake.