Effect of antropogenic pollution of waterbodies on morpho-physiological and biochemical parameters of Perca fluviatilis Linnaeus, 1758 in different seasons of the year

Purpose. To study the change in morphophysiological and biochemical parameters of perch females during different seasons and under the effect of human impact. Methodology. Fish were caught with the use of hook and line gears. Morpho-physiological parameters of the perch, including gonadosomatic index, hepatosomatic index, spleen index were determined. The biochemical parameters were also determined including protein content, lipids, glycogen and malonic dialdehyde in tissues. Findings. Changes in morpho-physiological (liver index, spleen index, gonadosomatic index) and biochemical (glycogen, lipid and protein content) parameters in perch females for under excessive human impact were examined. In this paper, only a part of the total amounts of results were presented. A significant decrease in the content of energy-intensive compounds, in particular glycogen, protein and fats in fish liver in spring and autumn periods, as well as an increase in the content of malonic dialdehyde indicates an impairment of the rate of processes of plastic and energy metabolism in it. The change in this parameter confirms the presence of unfavorable conditions for the perch during the study. This water body is characterized by the most significant human impact on the ecosystem. As a result, stored compounds such as lipids and glycogen are additionally used. A significant variability of the liver index in fish with excessive human impact was shown. This was due to the peculiarities of the accumulation and use of energy-intensive compounds depending on the conditions of existence. Significantly lower values of the spleen index were observed in fish from the Lake Kyrilovske compared with the same parameter of fish from the reservoir. A 1.6-fold reduction in the gonadosomatic index (GSI) in perch females from the artificially polluted Lake Kyrilovske compared with fish from conditionally clean reservoir was also observed. This indicates the intense functioning of the reproductive system in conditions of chronic pollution of the lake. The liver tissues showed lower (by 43%) protein content in fish from the Lake Kyrilovske during all seasons compared to the perch caught in the reservoir. This indicates an additional use of protein compounds for adaptive processes. A difference between the studied fish samples according to physiological, biochemical, and morphophysiological indicators proves that they are in significantly different ecological and toxicological conditions. The deterioration of living conditions causes over-expenses of energy-intensive compounds, in particular glycogen, protein and lipids. Originality. For the first time, the results of changes in morphophysiological and biochemical parameters of perch females depending on the season and the level of human impact have been presented. The practical value. The obtained results can be used as criteria for assessing the physiological state of the perch and the ecological state of an individual lake or small reservoir as a whole.