Zooplankton as a food base of European vendace found in the skerry parts of the northern Ladoga lake

Multiple research data on the current state of zooplankton found in the northern skerry area of the Lake Ladoga are presented. It is shown that eurythermic warm water species’ complex consisting of zooplankton found in the littoral zone of the lake is of great value. Along with the year-round eurythermic species, seasonal warm-water species reach high numerical strength in the pelagic zone of the lake. By quantitative indicators of zooplankton the study area of the Lake Ladoga can be referred to а-mesotrophic type. Nutrition circumstances for the growth of larvae, fry, and adult vendace can be assessed as favourable. The leading role in the diet of vendace was played by Copepods and Cladocera. Their ratio in the food spectrum depends on the season and is determined by the temperature regime of the water body.