Management of lake fish populations and lake fisheries in Denmark: history and current status.

The development of lake fisheries in Denmark is described and the various management measures applied to lake fish populations reviewed. Over the last 100 years catch records revealed a peak in annual yield in the 1950s and 1960s, with a subsequent decrease in catches thereafter coinciding with increasing eutrophication of Danish lakes. In particular, catches of the most valuable fish, the eel, Anguilla anguilla (L.), have diminished. Lake fisheries are regulated by legislation to protect populations of lake fish of commercial and recreational interest and prevent overfishing. Management of lake fisheries includes stocking of, for example eel, trout, Salmo trutta L., and pike, Esox lucius L., and, previously, introduction of new species. Lately, management of the aquatic environment has favoured the desirable fish species, which are hampered in eutrophic lakes, with the exception of pikeperch, Sander lucioperca (L.), introduced in a number of Danish lakes. Biomanipulation has been carried out during the last decade to help rehabilitate lakes by either stocking of piscivorous fish or removing planktivorous fish. [ABSTRACT FROM AUTHOR]