RESULTS OF MONITORING OF KALANOID COPEPODS EURYTEMORA LACUSTRIS (РОРРЕ, 1887) POPULATION STATE IN LAKE VECHELIE

Тhe spatial distribution of E. lacustris in the lake depends on the temperature and concentration of dissolved oxygen. Most of the individuals inhabit water layers 12–19 meters – the zone below thermocline. The water tempera-ture in these horizons remains constantly low (4,5–6,7 °С). Average content of dissolved oxygen in hypolimnion varies with 3,0–7,1 mg/l. When the concentration of dissolved oxygen in the hypolimnion layers increases, crustacean popula-tion concentrates more deeply.
 The population density of E. lacustris in lake Vechelye in different years of research consisted 584–2877 indi-viduals per m3. Although the temperature, transparency and concentration of oxygen in the water of lake Vechelye stay favorable for the species and characteristic of mesotrophic lakes, E. lacustris tends to reduce the number of its popula-tion.