Role of Fish in Regulation of Plant and Animal Communities in Eutrophic Ponds

Alteration of fish communities resulted in marked changes in the Zooplankton, phytoplankton, and benthic plant communities in nutrient-rich ponds. In ponds containing dense populations of fathead minnows (Pimephales promelas) and brook sticklebacks (Culaea inconstans), intense fish predation resulted in sparse cladoceran zooplankton populations and turbid water dominated by dense blue-green algal blooms. In ponds containing no fish, or dense populations of largemouth bass (Micropterus salmoides), abundant Cladocera reduced phytoplankton densities through heavy grazing, and these ponds were characterized by clear water and dense growths of Elodea canadensis, Potamogeton spp., and Cladophora sp. Manipulation of fish populations to control unwanted algal blooms in shallow eutrophic lakes may yield dense growths of equally undesirable macrophytes and periphyton.