Assessment of water quality through an active biomonitoring approach using three-spined stickleback (Gasterosteus aculeatus)

The Interreg DIADeM program (development of an integrated approach for the DIAgnosis of the water quality of the river Meuse) was created in order to develop new tools to evaluate the quality of water bodies in the Meuse waterway across the FrenchBelgian border. The project aimed to bring together the various crossborder stakeholders concerned with the protection of aquatic environments (academics, operators, users) while informing citizens of the risks caused by the degradation of water bodies. The use and the relevance of the multibiomarker approach in different model species (fish, crustacean, mussel) to assess the water quality was an important part of the program. Among the different model species used, the threespined stickleback has gained interest for biomonitoring for several years, due to its ubiquity and its tolerance to pollution. For many years, a new active strategy based on the importation of caged sticklebacks in a study site have been developed. Within the scope of the DIADeM program, the caging strategy was used with stickleback as model species to discriminate some sites in a large scale on the Meuse basin. In that way, sticklebacks were caged for 21 days upstream and downstream the wastewater treatment plants (WWTPs) of Namur (Belgiun), CharlevilleMézière (France), Bouillon (Belgium) and Avesnes-sur-Helpe (France). A battery of biomarkers was assessed to represent different physiological functions, such as innate immunity (leucocyte mortality and distribution, phagocytosis activity, respiratory burst, antioxidant system (GPx, CAT, SOD and GSH content) and oxidative damages (TBARS), biotransformation enzymes (EROD, GST), synaptic transmission (AChE) and reproduction system (spiggin and vitellogenin concentration). Physiological responses were compared between each site but also with biomarkers levels measured in sticklebacks under control conditions. Study highlighted a decrease of innate immune system downstream the WWTPs, especially through an increase of leucocyte mortality and a decrease in phagocytosis activity. A slight induction of EROD activity was also noticed downstream the WWTP of Bouillon and Namur. Moreover, the use of active biomonitoring clearly discriminated the different study sites from the reference but also amongst themselves, demonstrating the efficiency of used tools to assess the quality of water and characterize types of physiological impacts on fish