Effects of Eutrophication on Fish Stocks in Baltic Lagoons

Abstract

Long-term catch data indicate that eutrophication affects the structure and productivity of fish communities in German Baltic lagoons and estuaries. The correlations between the biomass of young-of-the-year fish and some zooplankton fractions show that eutrophication in the Darss-Zingst Bodden region has resulted in increases in the stocks of herring, cyprinids and percids, whereas pike stocks have declined. On the other hand, eutrophication does not appear to be responsible for the decline of migratory fish stocks in coastal waters and the alteration of species dominance in estuaries. Eutrophication has been responsible for fish kills in recent years, but there are signs that eutrophication levels are now decreasing.