A synthetic indicator based on nesting trend to inform the general public about the status of sea turtle in France and its overseas territories

International audienceFrance and its overseas territories is hosting 6 species of sea turtles : the leatherback turtle (Dermochelys coriacea), the Loggerhead turtle (Caretta caretta), the green turtle (Chelonia mydas), the Olive Ridley (Lepidochelys olivacea), and the Hawksbill turtle (Eretmochelys imbricata), the Kemp Ridley (Lepidochelys kempii). The first five are observed on nesting sites. Based on SWOT Minimum Standard, the Groupe Tortues Marines France (GTMF) established in 2015 a national monitoring scheme through which all the actors are implementing morning patrols to counts crawls on nesting beaches. Monitoring effort is adapted by actors in the field according to SWOT recommandation optimizing nesting phenology modeling. Data are then analyzed thank to R package Phenology to produce trends taking into account possible shift in nesting effort along time. As nesting activity trends is a proxy of nesting female abundance, trends obtained for each species on every French territory hosting sea turtle nestings are then valorized to inform a synthetic indicator describing the overall trends of adult nesting female in France