REPAMEP - Réponse des palourdes aux stress environnementaux combinant métaux, efflorescences toxiques et pathogènes - Programme LITEAU.

The originality of this project consists in the interdisciplinary approach gathering the impact of toxic phytoplankton blooms and metallic pollution on health (behaviour, stress, immunity, genetic) and disease development of the Manila clam, an economieally important species. The Manila clam Ruditapes philippinarum is the second exploited bivalve in the world. It was introduced in Arcachon bay during the 80's and is today exploited by professional fishermen (57 licences). A 50% decrease of the stock was observed during the last five years. Beyond fishing pressure, a PhD thesis identified several diseases as potential threats, like perkinsosis (=Dermo) and brown muscle disease (BMD). The project confirms the settlement of these pathologies with high prevalence and intensity, impacting clams growth and condition index. Perkinsosis and BMD rather develop in elevated mudflats with lower water turnover (north-western area). The hypothesis that the BMD agent would be a virus is still valid although it had not been yet demonstrated. Phytoplanctonic related toxins in Manila clams remain very low but the occurrence of spirolids justifies our project to experiment multi-contamination. Beyond the technological challenges (toxic algae culture, multitreatments and multi-responses protocol), this project highlighted effects of "toxie algae" and/or "metal" contamination on histologieal, immune, behavioural and molecular parameters. Our expertise was partly acquired with the assistance of the Fishing Committee and, in return, provided help this Committee for their own fishing strategies