Monitoring of pen pen populations along the Occitan coast

At the beginning of 2018, the Occitanie region launched a project aimed at carrying out an exhaustive census of the populations of large mother-of-pearl (Pinna nobilis), along its coastline and particularly in ports connected to lagoons (Port de Sète, Port Leucate). The objectives of this project were to identify the spatial distribution of populations on the Occitan coast, to assess their status, to characterize these populations and finally to estimate the factors influencing the recruitment and survival of individuals. Based on surveys carried out among the various users and managers of the coastline (port managers, fishermen/oyster farmers, marine protected areas, divers/kite-surfers), many dives were to be carried out in the areas indicated. The objectives of these dives were to determine the densities and abundances by site and to carry out biometric measurements in order to estimate the maturity of the individuals. Finally, tissue samples had to be taken to carry out genetic analyses in order to try to understand the population dynamics between the different environments studied (Mediterranean Sea, ports, lagoons). The results of this study should allow port managers to better understand the colonization of their infrastructures, but also provide information to improve the conservation of this protected species which is currently threatened with extinction by a protozoan parasite.