Microbiocenosis of carp (Cyprinus carpio) of the educational and experimental farm of KSTU (Kaliningrad region) for the three-year period from 2018 to 2020

Increasing fish farm productivity criteria with the help of various intensification measures (feeding fish, fertilizing ponds, increased stocking densities) leads to the emergence of fish infectious diseases. Educational and experimental farm is a multi-level pond farm that contains spawning, nursery and feeding ponds. It is used for commercial carp cultivation. On its territory, amateur fishing is also carried out. While studying pond economy, most frequently we register diseases of a bacterial nature. Test material has been carps of different ages. The primary bacteriological sowing has been carried out according to the method generally accepted in ichthyopathology. Microorganisms have been identified to genus and species with the help of a combination of cultural, morphological and physiological & biochemical signs using the Bergey bacterial manual. Microbial pathogenicity has been identified on the basis of proteolytic activity. The species composition of the carp microflora of the educational and experimental economy of Kaliningrad State Technical University in the period from 2018 to 2020 has been studied. As a result of microbiological analysis, groups of sanitaryindicative, saprophytic and opportunistic miscroorganisms have been identified. Isolation from the blood and parenchymal organs of bacteria of the genus Pseudomonas and Aeromonas, which can serve as virulent agents, indicates a possibility of carp infection due to the cultivation technology violation. When bacterial infections in pond farming happen, the economic damage can be significant, and treatment can be very expensive. Opportunistic bacteria that colonize pond farm carp can become virulent and provoke occurrence of epizootic process if fish resistance weakens and stressful conditions for the fish occur. Bacterial epizootics develop very quickly and can cause death of the entire fish stock in a pond farm. Therefore, any disease is better to prevent than to cure. But in order to develop preventive measures, it is necessary to constantly monitor the causative agents of various bacterial diseases in the pond economy.

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