Natural forage base and its impact on productivity of nursery ponds

Abstract

The article shows the results of zooplankton research in the nursery ponds during the vegetation period in 2015 on the basis of the fish–breeding farms «Rudnyky» «Lviv oblrybokombinat» and «Velykyi Liubin» (Lviv research station of the Institute of Fisheries of NAAS of Ukraine). It is defined that researched ponds have 76 taxonomic units of zooplankton, represented by rotifers (Rotatoria) and crustaceans (Cladocera and Copepoda). Among certain hydrobionts, 36 species belong to the class Rotatoria, which is 46.4% of the total number of species. 24 species (32.4%)of crustaceans belong to the suborder Cladocera, and the least number – 16 species (21.2%) belongs to the order Copepoda. The identified species are mainly pond forms that can occur in rivers and lakes. The most represented genera are Asplanchna, Brachionus (rotifers); Ceriodaphnia, Daphnia (cladocerans), Acanthocyclops, Eudiaptomus (copepods). Zooplankton number and biomass fluctuations are caused by seasonal changes in its dynamics, fish press and hydrochemical regime in the ponds. The paper presents the results of the research of fishery indicators of carp fingerlings in the nursery ponds of farms in Lviv region. It was established that the fishery indicators were subjected to significant fluctuations depending on the natural forage base of ponds.