Increased water turbidity reduces Notonecta melaena predation on the crayfish Procambarus clarkii: an experimental approach

Abstract This study investigates the hypothesis that increased water turbidity reduces the efficiency of native aquatic predators in controlling invasive species. We tested whether turbidity affects the predation behavior of the aquatic bug Notonecta melaena Kirkaldy, 1897, on juvenile stages of the invasive crayfish Procambarus clarkii (Girard, 1852). Under controlled laboratory conditions, we exposed predator–prey interactions to varying turbidity levels and assessed changes in prey acceptance and consumption time. The results revealed that higher turbidity significantly reduced the probability of prey capture and slightly increased the time required for consumption, indicating that probably the visual impairment under turbid conditions limits predator efficiency. These findings suggest that water clarity plays a key role in mediating the effectiveness of natural predation on invasive species such as P. clarkii . Enhancing water transparency in freshwater habitats may improve the effectiveness of native predators like N. melaena , offering a complementary strategy for the biological control of P. clarkii . By demonstrating how environmental conditions influence predator–prey dynamics, this study underscores the importance of integrating abiotic factors such as turbidity into management strategies for invasive aquatic species. These insights contribute to a broader understanding of ecological interactions and support more effective, ecologically informed approaches to invasive species control and freshwater ecosystem restoration.