There is currently a growing concern about the impacts of climate change, over-fishing and fisheries bycatch on marine environments and natural resources worldwide. A worrying example is notably the jellyfish proliferation to the detriment of other marine organisms in overexploited marine ecosystems. This shift may have high ecological and economical consequences. High trophic level predators integrate and amplify the effects of environmental forcing on lower levels throughout food chains while migrants are integrators of global processes as they may feed in some parts of the world and reproduce in others. The oceanic “jellyvore” multi-year migrant leatherback turtle may thus constitute a key bio-indicator of short- and long-term changes in food-webs and resource availability in marine ecosystems. This project will thus focus on the adaptive strategies of this critically-endangered species facing environmental constraints and will tackle one of the most important questions relating to the global change impacts on marine biodiversity. We will assess for the first time in marine turtles the links between the environmental conditions and the individual life history strategies, i.e. the individual migration, storage and reproductive strategies. Through a European collaboration between the Royal Netherlands Institute for Sea Research (NIOZ, the Netherlands) and IPHC (CNRS, France), I will be able to use stable isotope and original tracking techniques to investigate the migration and storage strategies of female leatherbacks of known-identity and known-reproductive history. Such a unique long-term database is available in French Guiana, one of the main leatherback’s nesting sites in the world. This project will help better understanding the underlying factors of leatherback population’s dynamics in the context of global change and ultimately help investigating how natural and human-driven environmental changes affect marine ecosystems.