Governing the decline: clam fisheries and the challenges of decentralized management across the western Mediterranean and Gulf of Cadiz (Spain).

Over the past four decades, clam fisheries along Spains Mediterranean and Atlantic coasts have exhibited significantly different ecological and governance trajectories. This study synthesises long-term landing data from 1993 to 2024 with a systematic review of regional legislation to explore how management frameworks influence the resilience of fisheries. In the northwest Mediterranean, which includes Catalonia, the Valencian Community, the Balearic Islands, and Murcia, fisheries have experienced synchronous declines, a consequence of overexploitation, fragmented governance, and reactive, top-down regulation. In contrast, Andalusia, encompassing both the Atlantic and Alboran Sea coasts, has demonstrated more resilient trajectories, bolstered by greater ecological productivity and the adoption of adaptive governance strategies since the 2010s. In this region, the implementation of gear-specific management plans, rigorous scientific monitoring (including satellite tracking), and prompt administrative responses have facilitated more sustainable exploitation. Our findings highlight the necessity of aligning governance with ecological connectivity and integrating adaptive co-governance structures that engage fishers to safeguard the future of small-scale fisheries. More broadly, this research emphasises the need for coordinated superregional or national management frameworks that incorporate ecological knowledge, promote stakeholder participation, and allow for timely regulatory adaptation.