EFFECTS OF HYDROPOWER PLANT ACTIVITIES ON FISH POPULATION, ABUNDANCE AND DISTRIBUTION
Andrzej Świerzowski*, Małgorzata Godlewska**
*The Stanisław Sakowicz Inland Fisheries Institute in Olsztyn, Poland
**International Centre for Ecology, Łomianki, Poland
ABSTRACT. The results of hydroacoustical monitoring in three water ecosystems exposed to anthropogenic pressure are presented. One is Żarnowieckie Lake, where a hydroelectric power station is operating, the second is a system of three lakes that are periodically included in the cooling system of the Konin-Pątnów power plant, and the third, the Solina Reservoir, is a typical dam reservoir situated in a recreational, mountainous area. In all three ecosystems, the fish distribution, biomass and migrations showed different patterns dependent on the environmental conditions and their changes due to human activity. In Żarnowieckie Lake, fish abundance increased during summer about four-fold as the probable result of fish migration from littoral to pelagic water, while in the Konin lakes it decreased 2.7 times as the result of fish migration to the lakes affected by the power plant’s operation. In the Solina Reservoir, fish abundance was 20 times lower than in the other two ecosystems, which was probably due to high fluctuations in the water level. This prevented the development of the littoral and affected fish breeding grounds.
Key words: HYDROPOWER PLANTS, HYDROACOUSTICAL MONITORING, FISH DISTRIBUTION, MIGRATION