Pathomorphological state of fish in the southern water area of Lake Ladoga

Abstract

The entry of pollutants and nutrients in various ways (wastewater, aerogenic means and polluting surface runoff) had a negative impact on all parts of the cycle of substances in the reservoir. This was clearly shown by the results of a comprehensive study in the water system: lake. Ilmen - Volkhov river - lake. Ladozhskoye - r. Neva and Neva Bay, which especially affected the ichthyofauna of the studied reservoirs, both visually and during pathomorphological examination.
The southern waters of Lake Ladoga are of great fishery importance. More than half of the water area is occupied by the littoral zone - the shallow part of the lake, limited to a depth of 8.4 m. The hydrological features of this water area, combined with sources of pollution, form a high level of anthropogenic influence, which affects the condition of fish and their reproduction. Fishing was carried out in three water areas of the southern part of Lake Ladoga, in the littoral zone. For the study, they took the brain, gills, liver, kidneys, spleen, and gonads.
All studies of fish have shown massive toxicosis at the organismal level. A pathological and morphological study carried out at the cellular level confirmed the previously obtained results, revealing pathological changes in various organs. These changes are expressed in hemodynamic disturbances and various degenerative processes, including necrosis, which is the result of prolonged exposure to toxicological substances. On histological preparations, changes in the structural elements of gill tissue from petals to capillaries were observed.
The conducted studies showed, along with previously conducted pathological studies, their effectiveness in assessing the condition of fish. They also make it possible to assess both the quality of the fish habitat and the level of its pollution.