Individual study: Fish capture rates of little egrets Egretta garzetta are significantly reduced by raising fish pond water turbidity, southern France
Cezilly F. (1992) Turbidity as an ecological solution to reduce the impact of fish-eating colonial waterbirds on fish farms. Colonial Waterbirds, 15, 249-252
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Increase water turbidity to reduce fish predation by birds
A randomised trial in southern France found that little egret Egretta garzetta foraging efficiency (capture rate) declined significantly in turbid water, under captive conditions (Cezilly 1992). A 3 x 6 m pool (water depth 10 cm) was used. Nine adult egrets either foraged alone or in threes. Three trials were undertaken using clear or turbid water, with three densities of prey i.e. mosquito fish Gambusia affinis (1, 2, and 4/m²). Treatment order was randomised and trials lasted 5 min. Turbid water was created by adding clay (Secchi disc lost from view at 10 cm depth).