The effect of pollutants on the ichthyofauna of Lake Ladoga and preventive measures

Abstract

Lake Ladoga is the largest body of water in Europe with huge reserves of drinking water, and has a particularly important sanitary and hygienic significance for the Northwestern region of Russia. The lake has significant fishery importance – annual catches reached 6000 tons. per year. However, over the past few decades, the fishery status of the reservoir has changed significantly. Stocks and catches of the most valuable fish species have sharply decreased as a result of anthropogenic impact – pollution and eutrophication.Chemical-analytical studies of samples of water, bottom sediments, atmospheric precipitation and fish for metals were carried out in the laboratory of fishery ecology of the St. Petersburg branch of the Federal State Budgetary Institution "VNIRO" ("GosNIORH" named after L.S. Berg) on an atomic absorption spectrophotometer AA - 7000 (Shimadzu) according to approved methods (PNDF., 2010; M02-2406., 2013 and M02-902-125, 2005), and in the research laboratory of food and natural objects "ANALECT" of the Institute of the Ministry of Health of the Russian Federation, using the method of atomic absorption spectrometry according to approved methods. Hydrochemical and hydrological parameters were determined using an automatic multiparameter probe Aqua TROLL 500.The southern water area of the lake, which is the most valuable in terms of fisheries, turned out to be the most vulnerable to toxicological effects. Pollution of spawning grounds, toxicosis of fish, violation of natural reproduction in combination with the hydrological features of the reservoir have led to irreversible transformations in the structure of the ichthyofauna as a whole for the entire lake. Pronounced consequences for the ichthyofauna of the reservoir are associated with the sensitivity of fish to pollutants, their ability to accumulate pathological information over a long-life cycle. The hydrological features of the southern water area of Lake Ladoga, combined with the location of pollution sources and the routes of pollutants, make it difficult to carry out preventive measures in this most important fishery area.