Sur quelles connaissances se baser pour évaluer l'état de santé des populations de truite commune (Salmo trutta)?

Abstract

The renewed emphasis on the concept of ecosystem health highlights society's interest in taking measures to protect environments affected by human activity. The criteria used for evaluating fish population health are rarely discussed within the scientific community. The present study attempts to discuss these for brown trout (Salmo trutta), a flagship freshwater species typical of headwater streams which represent most of the French hydrographic network. This initiative aimed at gathering ideas from a limited number of experts on the criteria for evaluating trout population health. The main key parameters were identified and organized into a hierarchical framework for each development stage. A consensus emerged on the fact that at the current state of knowledge, a diagnosis can be established based on the analysis of essential abiotic parameters but with more difficulty on the analysis of biotic parameters. For all development stages, the identified parameters are linked to habitat (substrate, hydraulic parameters, temperature and water quality), hydrology and connectivity. Further knowledge is required to identify relevant biological criteria. This implies long-term biological monitoring and research programs to better understand and identify biological parameters and their variability as well as relevant spatiotemporal scales and functional processes. © 2014 EDF.