Lake restoration by biomanipulation: Round Lake, Minnesota, the first two years

Abstract

SUMMARY. 1. Rotenone was applied to Round Lake in the autumn of 1980 in order to eliminate predominantly planktivorous and benthivorous fish. The lake was subsequently restocked with a higher population density of piscivores. The effect of this biomanipulation on the phytoplankton and zooplankton communities and on total nutrient concentrations was monitored at fortnightly intervals during the summers, from May 1980 to September 1982. 2. The abundance of phytoplankton was much lower after biomanipulation and was consistent with observed changes in Secchi disc transparency, total attenuation coefficient and chlorophyll a concentration. Zooplankters were also less abundant in 1981 and 1982 but the decrease in numbers was more than offset by the large increase in the mean sizes of the zooplankters present, so that the estimated grazing pressures in 1981 and 1982 were at least double the 1980 value. 3. Daphnia, rare in 1980, became the dominant genus in 1981 and 1982, and a shift to progressively larger‐bodied Daphnia species was observed. 4. Although total nitrogen and total phosphorus levels were generally lower after biomanipulation, their decline could not explain the reduction in phytoplankton abundance which was attributed to the increased grazing pressure. Possible causes of the observed declines in nutrient concentrations are discussed.

A Bibliometric Analysis of Lake Restoration with Submerged Macrophytes

“…Biomanipulation, proposed by Shapiro et al (1975) [143], refers to the manipulation of the fish community to reduce the predation pressure on herbivorous zooplankton, therefore increasing the grazing pressure on phytoplankton through the food web [144][145][146]. Trophic cascade interactions and top-down/bottom-up effects in lakes were proposed by Carpenter et al (1985) [147] and McQueen et al (1986) [148], respectively, which supplemented the potential mechanisms of biomanipulation.…”

Achieving conservation and restoration outcomes through ecologically beneficial aquaculture

“…This can occur by consumption of the selected species (e.g., stocking of weevils to control water hyacinth; van Driesche & Bellows, 1996) or release of a cultured vector that enhances pathogen spread to a selected species, although this can present significant risks to nontarget organisms (Secord, 2003). Further, biological control through biomanipulation can also be achieved by releasing a cultured predator to trigger cascading trophic effects and allow elements of a previously degraded ecosystem function to return (i.e., bioremediation) (Shapiro & Wright, 1984). For example, stocking cultured piscivorous fish to control planktivorous fish released zooplankton from predation pressure and benefitted water quality (Ha et al., 2013), and stocking cultured sea urchins onto coral reefs can reduce benthic algae and facilitate the recovery of coral reef ecosystems (Williams, 2022).…”

Failures to disagree are essential for environmental science to effectively influence policy development

“…While the ecological discussion was ongoing, the top-down view was widely implemented in situations needing urgent ecosystem management. In eutrophic lakes and ponds, this took the form of biomanipulation, altering food chains with the intention of leading to more algivorous zooplankton and less phytoplankton (Carpenter & Kitchell, 1988;With & Wright, 1984). Massive human interference such as removing and killing planktivorous fish or introducing piscivorous fish or herbivores (such as mussels) resulted in short-to mid-term reductions in turbidity, but the long term ecological outcomes have been less positive (Jeppesen et al, 2012).…”