GAP2 is about making a difference to an issue of significance to the whole of society; the wellbeing of the marine environment and the sustainability of fisheries upon which society depends for food. It builds on the relationships, processes and plans arising from GAP1 by enabling Mobilisation and Mutual Learning (MML) actions that promote stakeholder participation in the debate on and development of research knowledge and structures relevant to emerging policy on fisheries and the marine environment.A broad range of stakeholders will participate, including actors from civil society organisations, research institutions, universities, national and regional ministries and media organisations. Their work will involve: participatory research actions that integrate the knowledge of stakeholders and scientists and render it useful for management and policy development, critical evaluation of the participatory processes and incorporation of the lessons learned into systems of research and decision making. Global networks will be developed to enable trans- and international cooperation on comparing and establishing good practice.The actions of the participants and the outcomes from GAP2 will provide a concrete realisation of specific Science in Society objectives for engaging the public in research, enabling effective two-way communication between scientists and other stakeholders, and helping to make policy based on scientific evidence and research knowledge. It will contribute to the aim of the Science in Society programme to enhance democratic debate with a more engaged and informed public, by providing better conditions for collective choices on scientific issues relating to sustainable management, conservation of ecosystem integrity and biodiversity of the marine environment.