Reconstructing long-term trends in a Mediterranean sea urchin fishery: socio-ecological insights for adaptive management

Sea urchin fisheries have long played a cultural and economic role in many Mediterranean coastal communities, yet their trajectories and long-term sustainability remain poorly understood. In Corsica (Mediterranean Sea), the harvest of Paracentrotus lividus (Lamarck, 1816) has evolved from a traditional seasonal activity into a regulated small-scale fishery facing increasing ecological and governance challenges. Understanding how this fishery has changed over time is essential for anticipating its future and informing adaptive management strategies. By combining long-term reconstruction, fishery data, professional fishers' knowledge, and ecological monitoring, this study reconstructs the trajectory and current dynamics of the sea urchin fishery. Reconstructed catches increased from approximately 30 t in 1950 to peaks exceeding 90 t in the early 2010s, while model-based estimates reached 124 t in 2012. In contrast, declared landings between 2014 and 2025 ranged from 24 to 69 t, with a decline in declared landings during the 2024–2025 season, when harvesting was also closed early after the management quota was reached. The number of professional sea urchin fishers, fishing operations and catches were unevenly distributed among Corsican prud'homies . Seasonal CPUE showed high variability but no consistent long-term decline (16.6–26.4 kg h −1 ). Recreational harvesting was not explicitly considered due to limited data availability, although it may also affect population dynamics. Ecological monitoring revealed significant seasonal reductions in commercially sized individuals following the fishing season. Together, these findings suggest that stable catch indicators may mask underlying demographic erosion in spatially heterogeneous systems. The Corsican case illustrates broader challenges faced by Mediterranean small-scale benthic fisheries and highlights the value of integrating fishery-dependent and fishery-independent indicators, spatially explicit ecological information, and local ecological knowledge to support more adaptive approaches to fisheries management and governance.