The central aim of the study is to create a greater awareness of the socioeconomic contribution of fisheries to inform policy formulation both in the fisheries sector and in the broader political economy linked to the sector. The economic and social contribution of fishing and the economic activities founded on fishing are frequently undervalued. In particular, the contribution of small-scale fisheries to livelihoods, to food security and food supply is often poorly recognized, partly because of weaknesses in compiling and disseminating knowledge on fisheries. Because of these knowledge gaps, policymakers have often neglected comprehensive efforts to manage this complex and politically sensitive sector. The study shows that official records substantially underestimate production, employment and fish consumption and economic activity associated with fisheries. The reasons include reduced investment in knowledge and statistical systems, a failure to capture diverse, dispersed or seasonal activities in standardized data collection schemes, fragmentation of data sources and sets, and weak human capacity in developing countries. The solutions begin with making the knowledge systems more relevant to decision making, thereby justifying investment in monitoring key indicators which are directly relevant to economic productivity of the fisheries, to their role in poverty reduction, in economic growth, or in food security.