Journal / Archives
УДК 597.553.2:597-12 DOI: 10.15853/2072-8212.2017.45.62-70Download the full article
Influence of some environmental factors on juvenile coho salmon Oncorhynchus kisutch reared at the Vilyuisky hatchery (Kamchatka) in 2017
In this study, we analyzed the causes of increased mortality of juvenile coho salmon reared at the Vilyuisky hatchery in 2017.
Based on the results of complex (virological, bacteriological, parasitological) studies of fish, it was established that the epizootic situation at the hatchery was satisfactory. The results of the histological and hematological studies showed structural abnormalities in the kidneys, liver and gills and degenerative changes in blood cells characteristic of toxicosis. Most likely, the increased mortality of fish arose against the backdrop of chronic toxicosis caused by poor-quality feeds and the periodic introduction of contaminated stream water in to the hatchery.
УДК 597.552.51:639.32(265)DOI: 10.15853/2072-8212.2018.48.19-30Download the full article
Current state of the health of pacific salmon (Oncorhynchus) in the aquaculture of Kamchatka
Results of complex virological, bacteriological, parasitological and histological examination of juvenile and mature Pacific salmon from hatcheries of Kamchatka in 2015–2017 are demonstrated. The most dangerous pathogens for salmon included the Infectious Hematopoietic Necrosis Virus (IHNV) and bacteria Aeromonas salmonicida subsp. salmonicida, the causative agent of furunculosis. An asymptomatic carriage of IHNV was revealed in mature sockeye salmon (O. nerka) from two hatcheries and chum salmon (O. keta) in one hatchery. An outbreak of the IHNwas recorded among juvenile sockeye salmon at one of hatcheries in 2017. For the research period A. salmonicidawas found at four hatcheries in sockeye salmon, coho salmon (O. kisutch) and chum salmon used for reproduction. Histopathological changes typical as chronic form of alimentary toxicosis were the most frequent in liver, kidneys and gastrointestinal tract of juvenile individuals. Serious structural changes of the organs and tissues as a result of water or alimentary toxicosis were revealed in coho salmon underyearlings in 2017.