Long-term trends in striped venus clam (Chamelea gallina) fisheries in the western Mediterranean Sea: the case of Ebro Delta (NE Spain)

All clam fisheries in the western Mediterranean Sea have dramatically declined in the last few decades. Recently, most have collapsed in Spain, resulting in job loss for hundreds of small-scale fishers. However, insufficient attention has been given to the profound significance of this socio-ecological crisis. We evaluated the historical, social, and ecological context of the striped venus clam (Chamelea gallina) fisheries in the western Mediterranean Sea, focusing on one of the main productive areas of this region (the Ebro Delta, Catalonia, NE Spain) to detect possible causes of the decline in clam landings. Different governance systems (self-governance, centralized governance, and de facto co-governance) had been successful in maintaining striped clam fisheries since they were established in the 1940s. However, since the industrialization of fishing fleets in the mid-1970s, a lack of reliable management (e.g., free access; conflicts between different interested parties) and a progressive increase in fishing capacity, fishing effort, and technological enhancements across the small fishing grounds have increased the vulnerability of the exploited stocks and set them on a collapse trajectory. We recommend the following management measures to promote the recovery of the striped venus clam stock and mitigate the loss of its ecological, social, and economic value: (1) the closure of the fishery in the Ebro Delta; (2) the preparation and implementation of a Spanish Management Fishery Plan to restore the striped clam fishing grounds; (3) the establishment of a supra-regional Management Plan for the striped venus clam on the Mediterranean coast of Spain.