A management plan for the boat seines, called sonsera, used in Catalonia to target sand eels (Gymanammodytes cicerelus and G. semisquamatus) and transparent gobies was drawn up in accordance with European Union rules. A Sand Eel Co-Management Committee was formally created with the specific mission of ensuring a sustainable fishery. The Committee is composed of public administrations, fishermen’s associations, researchers and NGOs. The process has two phases: first, a comprehensive study of the fishery and subsequent advice for the establishment of a management plan and, second, the implementation and monitoring of the management plan. The study of the fishery included the analysis of the ecosystem impacts of the fishery (mainly stock status, impact on sensitive habitats and by-catch) and was carried out in the wider context of an adaptive co-management process to respond to the requirements of an ecosystem approach to fisheries.