Seasonal dynamics of morphological and physiological parameters of scaly carp (Cyprinus carpio Linnaeus, 1758) juveniles from the Taromske fish farm

Purpose. To investigate of the seasonal dynamics of morphological and physiological parameters of scaly carp juveniles reared under the conditions of the Taromske fish farm in the Dnipropetrovsk region. Methodology. Morphological and physiological studies of the young-of-the-year and yearlings of the scaly carp were carried out according to conventional methods. Morphological and physiological parameters of carp young-of-the-year were determined at the end of the growing season; yearlings – during unloading of the wintering pond. Findings. The presented data shows morphological parameters, indices of organs, condition factor and hematological parameters of the young-of-the-year and yearlings of the scaly carp reared in the Taromske fish farm. The blood condition of carp yearlings was characterized by a high number of red blood cells, increased color index, high erythrocyte sedimentation rate, a decrease in lymphocytes with an increase in the proportion of neutrophils in the leukocyte formula and an increase in the number of monocytes. Changes in the hematological profile parameters of scaly carp juveniles indicate the presence of certain changes in blood parameters after wintering. The lowest indices of all organs were observed in fish caught in the spring, which is a consequence of body depletion after wintering. The reductions in the Fulton and Clark condition factors can be caused by the effect of stress on the physiological state of the fish body after the wintering period. The morphological and physiological parameters of the scaly carp indicated a sufficient degree of the preparation of fish juveniles for wintering that ensured a high survival rate. Originality. The indices of internal organs and hematological profile of this year and yearlings of scaly carp grown in the fishery zone of the Northern Steppe by extensive technology were determined. The investigated morpho-physiological parameters depended on seasonal factors and characterized the physiological state of carp juveniles. Practical significance. The obtained results can be used for additional assessment of the quality and general condition of carp seeds.