Sustainability of the gooseneck barnacle fishery in Asturias. Trends, drivers and lessons

Abstract

The past 50 years have witnessed an exponential increase in fisheries captures, which has lead to the overexploitation of 90% of all fishing stocks. This is mainly attributed to the open-access nature of fisheries, where fishers deplete fishing stocks in order to pursue their own interests. Nevertheless, a paradigm shift is occurring in fisheries management. Fisheries are shifting from the classical top-down approach to bottom-up community efforts. Moreover, humans are no longer seen as the disruptors of the ecosystem but as an essential part of a linked social-ecological system. As part of this paradigm shift strategies like community participation and holistic management approaches have been promoted. Nonetheless, in order to assess the performance of these alternative management strategies real-life experiences must be carefully analyzed. The Asturian gooseneck barnacle fishery is a unique example of a complex social-ecological system that has been co-managed for the past 20 years. It provides an ideal case study to test the effect of alternative management strategies on the long-term sustainability of the fishery. Here, we have assessed the sustainability of the Asturian gooseneck barnacle co-management system through time and disentangled some of the key socio-ecologic drivers for its success. First, we analyzed the history of implementation and the socioeconomic characteristics of the gooseneck barnacle co-management system. Next, we evaluated the effect of larval dispersal and landscape characteristics on the fishery and their management implications. Finally, we assessed how all these components led to a sustainable fishery despite the effect of external and internal feedbacks. The Asturian co-management system is comprised by 7 management areas with heterogeneous socio-economic backgrounds. The incorporation of fishers' knowledge has led to within-area fragmentation of the management units down to single rocks as small as 30 m long, which are managed according to different protection levels. The system has empowered resource users and provided an opportunity for the use of both scientific information and fishers' knowledge to be integrated in management guidelines. 73% of fishers agree that the co-management system is the only way to protect the resource. Our results suggest the adaptive capacity provided by the co-management framework has been essential to manage this heterogeneous fishery. As part of a holistic management approach, life history traits and landscape ecology must be incorporated in management measures. The gooseneck barnacle is highly affected by its environment; in Asturias the fishery is located at the fringe of an upwelling system, which drives their larval dispersal. Gooseneck barnacles in the Cantabrian Sea have a dispersal distance in the range of 10s of km that matches the scale of the co-management system. Furthermore, there is a positive correlation between catch rates and the intensity of upwelling 4-years before, this corresponds with the time it takes recruits to reach commercial size. Thus, management and conservation strategies in the area should consider the effects of coastal upwelling. The gooseneck barnacle is also heavily influenced by landscape-metrics. Distance to coast, coastal convexity at a scale of 25 km and wave exposure at a scale of 1 km appear to be driving the quality of the resource. This has severe management implications because fishers are biased towards harvesting high quality gooseneck barnacles, which are sold at higher market values. Thus, we generated a model that can predict high quality fishing zones with 72% accuracy. These findings stress the importance of incorporating landscape concepts and life history traits in holistic fisheries management. The Asturian gooseneck barnacle fishery has survived through 3 important changes: implementation of the co-management system, change in management policies and the national economic crisis. Through adaptive strategies, such as increased selectivity, diversification, and flexible management guidelines, co-management has succeeded in maintaining or increasing catch per unit effort throughout all management areas and has allowed stable mean market prices. The Asturian gooseneck barnacle co-management system provides important lessons on how to embrace adaptive capacity, incorporate scientific and fishers¿ knowledge in management guidelines, create cross-scale interactions, and empower resource users. The system has achieved sustainability throughout the past 20 years by employing a holistic, adaptive and participatory approach to fisheries management.