Biomanipulation

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.

[2] Lake Zwemlust, a hypertrophic pond used as a swimming pool in The Netherlands with an area of 1.5 hectares and an average depth of 1.5 meters, was treated in March 1987.

[3] The lake was drained and 1,500 kilograms of planktivorous and benthivorous fish such as common bream were removed by seining and electrofishing.

[2] In the summer of the second year, 1988, there was considerable plant growth and, possibly due to lack of predation by carp or minnows, an explosion in the number of snails, including Radix peregra var.

In addition to grazing by zooplankton the lush growth of macrophytes removed sufficient nutrients from the water to prevent algal bloom by phytoplanktons.