Socio-écosystèmes halieutiques des régions ultrapériphériques françaises. Rapport du Groupe de Travail Outre-Mer (GTOM) 2025

This report presents the main results of the French overseas working group (GTOM) gathered in the report entitled: The fisheries socio-ecosystems of the outermost regions (ORs). This work on fisheries socio-ecosystems (FSES) is part of the field of sustainability sciences through, on the one hand, multidisciplinary work bringing together ecologists, biologists, economists and sociologists, but also projects or meetings involving stakeholders. In a context where the acquisition of knowledge is more difficult and the evolution of long-term data collection, notably through the Ifremer Fisheries Information System (SIH), is much more recent than in French fisheries mainland, fisheries research has experienced a significant acceleration in recent years. Various factors are concurred to this coming together, in the context of major political stakes linked to French requests for European subsidies to support the renewal of OR fleets. Knowledge gaps has de facto led, since 2022, to a need for major investment for Ifremer, in human and financial resources, accompanied by some scientific partners (OFB-PNMM in Mayotte, University of Guyana, University of Western Brittany), to implement the short and medium-term actions necessary to compensate for the acknowledged deficiencies. This report therefore aims to bring together and share all this accumulated knowledge, and thus assess the progress made since 2022. In particular, the report presents validated assessment results for 42 coastal stocks (38 in 2024), and describes in detail the economic and social situation of the different fleets of the French ORs including for the first time, elements on accidentology of fishers The interactions with other uses of fishery resources (large-scale commercial fishing, recreational and subsistence fishing, illegal fishing) are also studied. The seafood sectors of the different ORs are also studied as well as the governance and regulation of fisheries. The impacts of fishing on ecosystems, other factors of erosion of populations and biodiversity and the implications for fishing are also discussed. Cyclone Chido and Tropical Storm Dikeledi, which struck Mayotte in December 2024 and January 2025, caused severe and lasting damage on land and at sea, deeply affecting local fisheries both economically and through significant impacts on ecosystems.