Socio-economic and ecological drivers and challenges: the sea urchin fishery of the central Portuguese coast

Abstract

Sea urchin harvesting on the central coast of continental Portugal is a traditional activity well rooted in the littoral community. The rock-boring sea urchin, Paracentrotus lividus, is mostly harvested for its gonads by professional and recreational fishers. Recent and renewed interest in this marine resource has led to a first assessment of the local sea urchin population’s current status and the characterization of its fishery. This baseline knowledge is fundamental to promote informed decision-making for the conservation and sustainable management of this important marine resource. Field observations and enquiries to local fishers were carried out between 2019 and 2021 along this coast to describe spatial and temporal variation patterns of key bioecological aspects related to the sea urchin population (e.g. distribution and size structure, gonadal index, recruitment) and to gather socio-economic data related with its fishery (e.g. effort, yield and impact, fishers knowledge and opinion on the state of the resource, current management and legislation). Sea urchins are locally abundant and its density varied across habitats, highest in tide pools and lowest in subtidal habitats, where a higher proportion of larger individuals (>5 cm) were found. The gonadosomatic index peaked from autumn to spring, declining in summer. Recruitment occurred from February to August, peaking in summer. Harvesting mainly occurred in winter and early spring, but involved less than 2% of the active fishers observed in the study area. Results suggest that the local sea urchin population and fishery are not currently threatened. The most important problems associated with this activity and its management are: the rapid increase in demand for this resource; the high uncertainty regarding the actual fishing effort; the lack of awareness and compliance with harvesting regulations (especially in recreational fishing); insufficient surveillance and official fishery data which hardly reflect the harvesting pressure.