Feeding of sunbleak (Leucaspius delineatus Heckel, 1843) from the pond of Noginsky district of Moscow region in February 2023

Abstract

The nutrition of sunbleak (Leucaspius delineatus) from the pond of Noginsk district of Moscow region in February 2023, owned by GNP “Yakor”, was studied. The aim of the study was to investigate the nutrition of sunbleak. To achieve this aim, the following tasks were performed: the age of the caught fish, their average length and weight were determined, the quantitative and qualitative composition of zooplankton in the reservoir was studied, the food boluses of the fish were considered in order to establish the frequency of occurrence of food objects in them, the intestinal filling index and the selection index. The study of the sunbleak nutrition seems relevant for establishing links in the ecosystem of a fishery reservoir, with the aim of further optimal selection of fish multiculture, based on the analysis of the state of the natural food supply. As part of the zooplankton community of the reservoir, 11 taxa were identified: 4 species of rotifers, 4 species of branchous and 3 taxa of copepods. In the course of the study, it was found that the sunbleak from the reservoir in question fed on almost all the species encountered except rotifers. With age, the fullness of the fish intestines decreased. The species composition of the consumed crustaceans differed depending on the age of the fish. Younger fish preferred the smaller size species of crustaceans, older fish preferred larger size and more nutritious species of crustaceans. Crustaceans of the Daphnia genus turned out to be the most preferable food for the sunbleak of all ages, and with age, the fish more and more preferred this food object. The most abundant crustaceans of the Bosmina genus in the water body were avoided by the fish, even the underyearlings, the only age category of the sunbleak that fed on these organisms.