Acute Ecotoxicity of Exposure to Sugarcane Ashes on the Behaviour of Predator and Prey Fish Species

Sugarcane, one of the world’s major crops, is used to produce sucrose and biofuel. Before harvesting, sugarcane is burned to facilitate manual cutting, generating ashes that may reach water bodies and cause the death of aquatic organisms. While studies have addressed the lethal effects of sugarcane ashes (SCA) on different fishes, little is known about the effects of sublethal SCA concentration on aquatic organisms. In this study, we evaluated the behaviour of a piscivorous ( Hoplerythrinus unitaeniatus ) and an invertivorous ( Moenkhausia forestii ) fish species, after a short-term (24 h) exposure to a sublethal concentration of SCA (0.8 g L −1 ). We hypothesized that the outcomes of predator–prey interaction would change when the players are subjected to sublethal SCA concentration. Our findings revealed that neither the behaviours of predator and prey fish species nor the outcome of their interactions was changed by the exposure to sublethal SCA concentrations, suggesting that their behavioural traits were not particularly sensitive to SCA. However, we emphasize that (i) other predatory and anti-predator behavioural traits could be affected by SCA even at under 0.8 g L −1 concentration and (ii) higher concentrations of SCA and/or long-term exposure may trigger profound changes in the behaviour of predator and prey fish species. Our findings are worrisome because there are new public policies to expand sugarcane production in Brazil, with the possibility of continuing burning sugarcane crops across the country. This will increase the input of SCA into aquatic systems, generating more prominent and pervasive negative impacts than those evaluated in this study.