Morphophysiological characteristics of European perch (Perca fluviatilis Linnaeus, 1758) and rudd (Scardinius erythrophthalmus Linnaeus, 1758) from Kyiv water bodies

Purpose. To study morphophysiological parameters of European perch and rudd from the urbanized water bodies of Kyiv in order to use them as indicators of the physiological state of fish. Methodology. The ichthyological study was carried out in different water bodies in Kyiv in May 2021. The material for the study were native species: European perch and rudd. Morpho-physiological parameters were determined separately for males and females. The probability of the obtained results was assessed by a Student's t-test (Р≤0.05). Findings. Differences in morpho-physiological parameters of European perch and rudd from two water bodies were studied. A high content of oil products in water (0.090 mg/dm3) and bottom sediments (80.5 mg/kg) was found in the Lake Kyrylivske, while their concentration was several times lower in water (0.005 mg/dm3) and bottom sediments (10.5 mg/kg) of the Lake Martyshiv. Differences in the living conditions were manifested in the studied samples of fish. European perch from the Lake Martyshiv had a higher body length and weight by 10.6% and 30%, respectively, compared to the sample from the Lake Kyrylivske. On the other hand, no significant differences in body weight were found for rudd. This indicates the presence of interspecies differences for the studied fish in the living conditions of water bodies under human impact. In addition, differences in morphophysiological parameters have been established in European perch. Condition factor of perch females from the Lake Martyshiv was 16.5% higher than that of females from the Lake Kyrylivske. High liver indices were observed in European perch males from the anthropogenically transformed water body, while rudd males had a liver index lower by 26.3% than that in the Lake Martyshiv. The confirmation of the stressful living conditions in the Lake Kyrylivske during the study period was a significant decrease in gonadal and spleen indices of European perch. Originality. It was established that males and females of European perch and rudd have different physiological reactions to negative living conditions, which were reflected in the indices of internal organs. Practical Value. The obtained results allow assessing the physiological state of most abundant fish communities in urbanized water bodies of Kyiv for further forecasting their abundance and structure.