Diet of European grayling (Thymallus thymallus (L.)) in the rivers of the Vologda region, Russia

The results of analysis of the qualitative and quantitative composition of the diet of European grayling 7 watercourses of the Vologda region, Russia. In the food spectrum recorded 30 representatives of taxo-nomic groups of invertebrates and vertebrates. The diet of the grayling formed 3-4 groups of organisms. A significant proportion of the mass is occupied by representatives of the Trichoptera (2.5-13.8%), Gordiacea (0.6-24.4%), Scorpaeniformes and Cypriniformes (2.4-67.4%), Gastropoda (1.1-16.9%). Quite often, but have less weight representatives of Formicidae (0.3-12.7%), Diptera (0.3-6.3%), Lumbricidae (0.6-24.4%), Ephemeroptera (0.7-5.7%). The basis of the diet of grayling in age from 0+ to 3 years are imaginal stages of Diptera and the larva of the caddis. With age, there is expansion of the food spectrum from 7 to 21 components. The older age grayling used as a secondary feed adult Hymenoptera, molluscs and earthworms. In spring and autumn the diet of grayling is based on the consumption of aquatic invertebrates (the larva of the caddis, molluscs) and fish. With the departure of amphibiotic insects in the food spectrum are equally represented on water and land and air organisms.