Morphofunctional correlations of the perch Perca fluviatilis in polluted lakes of the Middle Ob Region
The morphofunctional and histopathological state of the perch Percafluviatilis population in the lakes of the Middle ob region located in intensive hydrocarbon production areas has been investigated. The collection of ichtyological material was held in the summer of 2012 in polluted lakes of the taiga zone of Khanty-Mansi Autonomous okrug (Polyntur lake) and the Middle ob right riverside lakes (the Entllor and the Beloye). The size and weight parameters of fish and the concentration of hemoglobin in its blood were studied, also a histological analysis of the liver, gills and reproductive system was carried out. The technique of semi-quantitative analysis by assigning a significance factor to each specific abnormality was used to evaluate the histological preparations. It was found that the strongest linear and weight growth during development correlation changes were observed in the perch from lake Entllor, the least correlation changes-in the perch from lake Beloye. These results indicate differences of the water quality of these lakes. The highest concentration of hemoglobin in the blood is typical of the perch from lake Beloye. In addition, the hemoglobin concentration in females was greater than its concentration in males in all the studied lakes, due to a more intense reparation processes after spawning. Most of the fish had abnormalities in the liver: fat degeneration of hepatocytes, some fish had hyperemia, destruction of hepatic parenchyma. The histological analysis of the gills revealed pathological changes: cytolysis of gill epithelium, thickening, adhesion and destruction of the gill lamellae.In the reproductive system of both the macroscopic and microscopic levels in all studied specimens, no pathomorphological changes were revealed. The weak correlation of pathological changes of the liver and gill apparatus with the state of the reproductive system indicates its high immunity to extreme factors. A clear tendency was revealed:the increase of pathological changes in the direction: gonads - liver - gill apparatus, and the deterioration of water quality of the following lakes: Entllor - Polyntur - Beloye.