A fish multi-biomarker approach, including main physiological functions, to better determined global effect of contaminant on ecosystem
Résumé
Risk evaluation, due to the presence of toxic compounds in the environment, brings up the necessity to better understand their global effect on ecosystem. In this way, in addition to traditional biochemical biomarkers, some laboratories proposed to study the responses of biomarkers in relationship with the main physiological functions (reproduction, survival, maintenance, behaviour). This approach favors the evaluation of links between biochemical responses and individual/population effects. In this context, a multi-biomarker approach was used in four stations of a French river (La Loue – Franche-Comté region) surrounding area of drastic fish mortalities. In each station, 20 bullheads of both sexes were caught in spring and autumn by electrofishing for further biomarker analyses. The major results shown that the global health indicator (index condition, lysosomal membrane integrity and lipoperoxydation), the indicator of reproduction (gonado-somatic index and the maturation stage), the biotransformation enzymes and chromosomique damages were never modified regardless to station. Nevertheless, immune response and neurotoxic activity were strongly modified in the stations with fish decline. All these results could imply an important immune request and/or the presence of neurotoxic compounds in the river, inducing fish mortalities. This study showed the relevance of using multi-biomarker approach, including main physiological functions, to better determined effects of various contaminants on ecosystem health.