Reactions of Kidneys of Silver Bream (Blicca Bjoerkna) From Volga Delta to Habitat

Abstract

The article focuses on the intensive anthropogenic impact on the aquatic ecosystems, which makes it necessary to monitor the populations of different fish species. The method of mor-phophysiological indicators was used to study the kidneys of silver bream in different water bodies of the Volga Delta. The morphometric characteristics of the kidneys of silver bream are presented. It is shown that the reactions of organs and body systems are caused by the environmental impact on the living organisms, which results, in particular, in the pathological changes in the fish body. Reactions in the body of fish are the result of a combined effect of environmental factors and natural physiological processes related to feeding, migrations, generative cycles, etc. The detected changes in the organ structure make it possible to assess the impact of the environment on fish. The seasonal and sexual variability of the indices of the mesonephros of silver bream from the Volga Delta is shown. Analysis of the kidneys of fish from two water bodies showed the variability of kidney mass due to the anthropogenic load on the water body, in particular, an increase in the kidney index in silver bream Blicca bjoerkna was registered in the ecosystem with an increased toxic load. It has been stated that the increase in the relative mass of mesonephros was caused by the changes in the organ. Changes were detected both in the intratubular tissue, and in the convoluted tubules and renal capsules. The study helped to find the differences in the relative weight and structure of the kidneys of silver bream, which lives in the water bodies with different anthropogenic load. A real increase of the kidney index was found in fish from the water body with a higher level of anthropogenic impact.