The current ecological and ichthyotoxicological state of the Svir bay of Lake Ladoga

Abstract

A significant part of the water area of the bay is represented by a shallow littoral, which is characterized by the highest biodiversity and bioproductivity. Approximately 90% of benthic organisms known for Lake Ladoga are inhabitants of the littoral zone. The littoral and water areas gravitating towards it are a spawning and feeding place for all fish species living in the lake. The Svir Bay of Lake Ladoga is located in the southeastern part of the lake water area. Its area is 260 km2. The present study in the water area of the Svirskaya Bay with an assessment of the state of the ichthyofauna was carried out in the summer of 2022, and the previous one - in the eighties of the last century The article presents the materials of biological and chemical-analytical studies in the Svir bay of Lake Ladoga, which is of great fishery importance. The ecological and ichthyotoxicological state of the studied water area and the most important importance of the ichthyofauna in assessing the state of its individual sites are shown. Thus, the shallow littoral zone turned out to be more polluted compared to the more remote from the coast and more deepened southern part of the lake. A higher level of pollution of the littoral, which occupies a significant part of its water area, negatively affected the ichthyofauna of the reservoir and its reproduction, which led to an impact on fish stocks, especially valuable species, and the structure of the ichthyocenosis of the lake as a whole. The results of the research also showed that the condition of the lip as a whole has improved somewhat compared to the eighties of the last century, when the last ichthyotoxicological studies were conducted in this water area. Taking into account the state of the ichthyofauna and other indicators of the study, the pollution level of the Svir Bay of Lake Ladoga can be characterized as weakly expressed sublethal.