On October 21, 2025, we organized a co-construction workshop at Ifremer in Vairao focused on possible responses to marine heatwaves. This event was part of the ongoing work carried out under the MaHeWa project and brought together around thirty participants, including municipal representatives, environmental associations, staff from the Directorate of Marine Resources, members of the Interministerial Delegation for Climate and Sustainable Development, and several researchers involved in the project. The goal was to engage in concrete discussions about the impacts of ocean heatwaves and to identify collective actions to reduce their effects on ecosystems and human activities. As a reminder, a first workshop of this kind was previously held in Nouméa, New Caledonia.
This workshop marked a new step in the participatory development of the MaHeWa action plan. The aim was not simply to present scientific results, but to confront these findings with local realities, to listen to feedback from territorial actors, and to jointly build realistic intervention scenarios. Through these exchanges, we seek to better understand how marine heatwaves are perceived across territories and what types of responses could be practical, context-specific, and feasible.
This work is part of a long-term approach: establishing a network of actors capable of monitoring alerts, interpreting indicators developed by scientific teams, and coordinating responses in the field. We also began discussing the creation of a dedicated management unit that could respond to marine heatwave events, by identifying key stakeholders and the procedures to be activated.
French Polynesia has already experienced numerous marine heatwave episodes since the 1980s, with visible consequences such as coral bleaching and the mortality of certain species, notably giant clams. While ecosystems have so far shown good resilience, projections indicate that these events will become more frequent and intense in the coming years, with potential impacts on biodiversity, fisheries, pearl farming, and tourism. These challenges fully justify the collective effort we are undertaking through MaHeWa.
Similar workshops will continue to be organized until 2029, in French Polynesia, New Caledonia, and Wallis and Futuna. They will help refine proposals, test tools, and strengthen coordination among local actors. Ultimately, this work aims to develop concrete adaptation mechanisms and contribute to shaping regional public policies for managing the risks associated with marine heatwaves.
Photo credits: Ifremer in the Pacific.
