Diseases of different aetiologies in salmonids in Ukraine

Institute of Fisheries, National Academy of Agricultural Sciences, 135 Obukhivska St., Kyiv 03164, Ukraine The paper contains the results of the studies into the ichthyopathological situation of the invasion and infectious diseases of salmonids carried out by the Ichthyopathology Laboratory of the Institute of Fisheries of Ukraine from 2013 to 2016. The investigated salmonid species included: the rainbow trout Oncorhynchus mykiss, the brown trout Salmo trutta morpha fario, the brook trout Salvelinus fontinalis, and the European grayling Thymallus thymallus. The fish were sampled from aquatculture farms as well as natural water bodies and their diseases included invasive (parasitic) and infectious (viral and bacterial). The most frequently encountered invasions in the brown and brook trout were ciliates: Chilodonella pisci cola and Apiosoma conicum, Trichodina (in particular T. truttae and T. nigra), Ichtyophthirius multifiliis; monogenea Gy rodactylus birmani, and diplostoma Diplostomum spathaceum. Aeromonas and Flavobacterium bacteria were isolated from fry and young-of-the-year rainbow trout and brook trout. Y. ruckeri positive samples were isolated from the fish with the signs of yersiniosis. As for viral diseases, IPNV isolates (the first time in Ukraine) of the rainbow trout were first isolated in fish farms in the western regions of Ukraine. A phylogenetic analysis of these IPNV isolates was performed, which showed that they belonged to Sp strain and the European genotype.