Unravelling the mystery of a species’ ecology across life stages to improve its conservation: the beautiful story of the Green turtle in the western Indian Ocean

Jerome Bourjea

MARBEC, Ifremer, Univ Montpellier, CNRS, IRD, INRAE, Sète, France

jerome.bourjea@ifremer.fr

Link to onsite registration: https://duo.dr13.cnrs.fr/public/evenement/index

Link to seminar: https://umontpellier-fr.zoom.us/webinar/register/WN_udq-YSN_Q26oce240ABdGw

All oceans face growing anthropogenic pressures raising questions about the sustainability of their exploitation and conser-vation. Marine megafauna—such as large tunas, seabirds, cetaceans, sea turtles—are particularly vulnerable to these pressures, with entire populations at risk of disappearing. Understanding how marine megafauna respond to their envi-ronment during their life cycle is crucial for designing effective conservation strategies and reducing human-induced threats, such as fisheries bycatch. Marine turtles are of special interest both as emblematic species of marine diversity and because they have played a key role in developing species-based approaches to the conservation of habitats, communities and ecosystems.

The IUCN Red List is a critical tool for conservation assessment using a large range of information about species and eco-systems to assess extinction risk at the global scale when regional subpopulation information is lacking. So was the case of green turtle (Chelonia mydas), which is currently classified as Endangered globally by the Red List. A tremendous work by the IUCN Species Survival Commission’s Marine Turtle Specialist Group led to the definition of Oceanic Regional Manage-ment Units (RMUs) for all marine turtle species in 2010, enabling regional evaluation for these large migratory species. After decade of overexploitation, and thanks to a regional scientific research network established over 50 years ago in the western Indian Ocean (WIO), this seminar will present how the incredible adventure of transboundary science has led to major advances in our understanding of green turtle ecology and conservation in the WIO. Based on long-term data collec-tion and analysis  on several nesting sites (over 40 y), large population genetics analysis (>1000 samples), individual bi-ologging across life stages (over 200 tracks from adults and juveniles), dispersal modelling approaches, and efficient re-gional cooperation between countries, it was possible to define oceanic and priority conservation areas, taking into account both breeding sites and their associated ecosystems (coastal and oceanic).

All this work resulted in a new WIO regional assessment, which determined that the Green turtle can now be classified as “Least Concern” in this region, a testament to decades of dedicated species and ecosystem conservation efforts.

Watch previous seminars on our YouTube channel: https://www.youtube.com/channel/UCrX4IsZ8WIFcDa0ZmC7rcQg