Modelling BPA effects on the three-spined stickleback population dynamics in mesocosms to better understand the populational effects
Résumé
Bisphenol A, a well-known endocrine-disrupting chemical, is ubiquitously present in an aquatic environment. Its impacts at populational level on three-spined sticklebacks have been studied in a long-term mesocosm experiment at low-dose BPA, however the causes explaining the observed effects have remained unclear. Here, we used an individual-based model coupled to a Dynamic Energy Budget model for (i) assessing the potential of modelling to predict impacts on population viability from organism ecotoxicological endpoints and (ii) provide insights on the mechanisms of BPA toxicity in the artificial streams. To do that, both direct and indirect effects of BPA on three-spined sticklebacks were incorporated in the model. BPA impacts on the physiological processes of fish have been identified based on literature data and effects on stickleback preys have been t into account using sampling data from exposed mesocosms. Simulations were made with the model integrating dose-responses only calibrated on literature data to assess the predictive capacity of the model. Then, simulations were made with a re-calibration of the toxic parameters on the populational data to better understand the observed BPA impacts found in mesocosms. Results showed that direct BPA effects on fish (impacts on gonad formation, growth, male reproductive behavior, eggs and larvae survival) mostly explained the three-spined stickleback population structure in mesocosms, but indirect effects were not negligible. Hence, this study showed the potential of modelling in risk assessment to predict the impacts on the fish population viability from behavioural and physiological effects measured on organism in controlled conditions.