Changes of Structure and Stock in Exploited Fish Communities in Estuaries of the Southern Baltic Coast (Mecklenburg‐Vorpommern, Germany)

By means of analyses of catch values of selected fish species possible effects of eutrophication on the estuaries are described. Although the registered stock changes are not only a result of eutrophication a stock increase in pikeperch could be verified at the end of the first half of this century. With progressive eutrophication a great decline of migratory fish stocks took place at the end of the sixties/beginning of the seventies. The decline of eel stocks is not caused by eutrophication. Afterwards pike stocks show an aggravating decline in hypertrophic estuaries which are related to the decline of macrophytes. Baltic whitefish has still kept up its stock level under these conditions. Symptoms for a growing danger of an unexpected disaster are increasing to the whole fish community of extremely polluted waters.