THE INFLUENCE OF ENVIRONMENTAL FACTORS OF AQUATIC MEDIUM ON MORPHOLOGICAL AND PHYSIOLOGICAL INDICATORS OF PIKE-PERCH AND PERCH

Purpose. To study morphometric and morpho-physiological characteristics of percids from geographically separated areas and select the integrated indices of these fish, which characterize the ecological status of the individual water bodies. Methods. Fish were caught by net and angling fishing gears. Morphometric analysis of fish was performed for 19 plastic and 6 meristic features. For mathematical treatment, plastic features were equated with fish body length, while dimensions of the head with the length of the head. Comparison of mean values was performed using Student’s t-test. Indices for internal organs were assessed by equating weight of organs to fish body weight. Results. A comparative characteristic of morphological indices of percids is presented for different water bodies. Based on the difference of plastic and meristic features, it was shown that the studied perch belonged to isolated populations. Significant differences in body length, weight and hepatic index were found that was related to environmental conditions in which perch exist. Based on fish condition factor values, it was found that the best conditions for foraging were in the studied stretch of the Ross river. Also found that pike-perch had insignificant phenotypic variability in morphology Originality. Percid populations of the Ross River, Dnieper River (Vita River delta), Kirillovskoe and Babino lakes were studied based on morphometric and morphophysiological features. The differences between percid populations indicate on its environmental polyvalence. The practical value. Dispite on adaptation of perch to different environmental conditions, its physiological status may be used as one of criteria for assessing the ecological state of ecosystem.