Study of the losses of Siberian sturgeon (Acipenser baerii) due to gill infection with Diclybothrium armatum in sturgeon farms of Qom and Mazandaran provinces

Sturgeon is one of the most valuable aquatic species in the world and is of great commercial and economic importance. Monogenean trematode Diclybothrium armatum is one of the parasites which is specific to its host and after invading the host, causes symptoms such as respiratory system disorders, multiple gill injuries, decreased mobility, surface swimming, swallowing air bubbles near the water surface, and persistent losses occur in Siberian sturgeon. The aim of the present study was to investigate the causes of losses in Siberian sturgeon farms of sturgeon farms in Qom and Mazandaran provinces. In this study, 20 Siberian sturgeons with a size of 80 to 90 cm during the months of May and September 2016 from sturgeon farms were referred to the aquatic animal clinic of the faculty of veterinary medicine, university of Tehran and in terms of characteristics and appearance, were examined and monitored. In the initial macroscopic examinations, a number of parasites were visible in the gills of Siberian sturgeon with the naked eye, but there was no sign of the presence of parasitic pathogens in the gills of starry sturgeon and beluga fish. Then, in order to better investigate the parasitic infections, a wet smear was prepared from the gill tissue of fish and carefully examined under a light microscope. Based on the available diagnostic keys, the presence of Diclybothrium armatum monogenic parasites in the gills of Siberian sturgeon was confirmed. In order to treat the infected fish, a salt bath (to increase the salinity of water) was prescribed at a rate of 20 g / l for 7 days (1 hour daily).