Gustera Blicca bjoerkna (Linnaeus, 1758) of small reservoirs of Central Russia

Abstract

The question of the fishery significance of the gustera inhabiting the reservoirs of the Smolensk, Moscow, Ryazan and Kursk regions is considered. The occurrence of gustera in the catches of fixed nets with a mesh pitch of 30–50 mm is shown on the example of small reservoirs in Central Russia. Its share in net catches directly depends on the thermal regime of reservoirs and increases in the direction from north to south, from the Moskvoretsko-Vazuzskaya group of reservoirs to the reservoirs of the Kursk region. The greatest importance of the cluster is in the structure of ichthyocenoses of cooling reservoirs of nuclear power plants and GRES. Depending on the morphological features of reservoirs, the main biotopes of the gustera are the sublittoral zone and the flooded floodplain in the depth range from 2 to 8 m. Using the example of the Mozhaisk reservoir, it is shown that the share of gust in the structure of the fish part of the community has not changed significantly over the fifty-year period of its existence due to the relative stability of the ecosystem of this reservoir and operation in the mode of a drinking reservoir. The highest indicators of the weight growth of gust are characteristic of cooling reservoirs of nuclear power plants and GRES, as well as Kursk reservoirs. Significantly inferior to them is the gaster from the colder-water Vazuz and Moskvoretsky reservoirs. The onset of puberty in the gustera inhabiting the reservoirs of Central Russia, as well as growth, is closely interrelated with the thermal regime of these reservoirs and the duration of the feeding period. In the absence of industrial fishing and a low degree of development of the reserves of gustera by amateur fishermen, in most reservoirs of the group under consideration, a high biomass of this species is observed in the range from 25 to 116 kg/ha. When highly productive benthic fish are introduced, gustera will be their competitor in nutrition and significantly reduce the efficiency of reservoir stocking. It is recommended to suppress the number of gustera by intensifying amateur fishing and mass stocking of reservoirs with predatory fish species.