biomanipulation

Biomanipulation is the deliberate alteration of an ecosystem by adding or removing species, especially predators.

==Aquatic ecosystems== Changing the fish population of bodies of water as a part of watershed management can facilitate desirable changes in aquatic ecosystems suffering from eutrophication characterized by domination by phytoplankton aiding ecosystem restoration, an application of restoration ecology. In ponds or lakes alternative stable conditions, one with high algae populations, little other plant life, and turbid water, another with low algae populations, a diverse plant population, and clear water, may exist. In addition to prevention of excess nutrients such as phosphorus and nitrates, removal of certain fish species adapted to turbid water may facilitate change from one steady state to the other, an application of dynamical systems theory. Fish species may be removed by means of poison, harvesting, or introduction of predatory species. As a different fish community will result from the process it will affect recreational and commercial fishermen whose cooperation or opposition is important.