Parasites of sturgeon fish in the conditions of artificial reproduction in the Astrakhan region

Abstract

Due to the reduction of stocks of valuable sturgeon species, the restoration of which is difficult due to the lack of natural reproduction, limited scale and low efficiency of artificial reproduction, the development of sturgeon breeding in the Astrakhan region in recent decades remains the most relevant direction of the fishing industry. The main damage to fish farms is caused by infectious and invasive diseases. Epizootic well-being of enterprises depends largely on timely applied preventive measures, ichthyopathological monitoring and production control. This paper presents the results of a parasitological survey of different age groups of sturgeon fish in conditions of artificial reproduction, which is one of the methods for assessing the epizootic situation on a fish farm. The parasitofauna of Russian sturgeon and Beluga combined ectotrophic organisms of a direct development cycle widely distributed in aquaculture — protozoa, crustaceans, leeches. Producers of Beluga and sturgeon larvae each have two types of parasites with a low level of infestation. Producers of Russian sturgeon were distinguished by their parasitic purity. The qualitative composition of parasites of young sturgeon fish grown in ponds was more diverse and in different years included 5-6 species with a predominance in young Russian sturgeon. This age group had the highest level of invasion by epizootically significant parasites. The 35 % of the examined fish had mixed infestations. The parasite fauna of larvae and juveniles of Russian sturgeon and Beluga combined common species: Ichthyophthirius multifiliis and Ichthiobodo necatоr. The detected organisms did not show pathogenicity to their host, but the presence of parasites with a high epizootic potential indicates the preservation and functioning of the centers of infestation on the farm.