8. Fish community

The changes in fish community and population parameters (abundance, biomass and fish growth) in Lake Drūksiai as a cooler of the Ignalina Nuclear Power Plant (INPP) were investigated. In view of ecological processes taking place in the lake, the following three stages were distinguished as being of great importance for the species composition, community structure and biological productivity of ichthyofauna of the lake: the period of basic state of the lake before the beginning of construction of the INPP (1950–1975), the period of intensive exploitation of the INPP (1976–2009), and the period of closure of the INPP (2010–2012). Investigations carried out before exploitation of the INPP are compared with the results obtained during plant operation at different capacities. Ichthyological investigations in different sites of the lake revealed changes in fish species diversity and community structure due to changes in thermal regime and intensive anthropogenic eutrophication. The growth rates of dominant fish...