This thesis explores small-scale fisheries trade, markets and the accompanying relationships. It does so to understand how they contribute to human wellbeing and ecosystem health through fisher's behaviour in the marine environment. The capacity of small-scale fisheries to provide for fisherfolk and wider society is currently challenged by human induced ecological threats such as overexploitation and climate change. Small-scale fisheries are increasingly incorporated into the global trading system, which in part drive these ecological changes. At the same time these fisheries are important providers of food and livelihood security for millions of people worldwide. How to realise better fishery governance approaches and enactment is therefore paramount. This thesis attempts to address knowledge gaps in governance and research that centre around the market and actors within it- an area little included in governing fisheries. I draw on the value chain concept and use a mixed methods approach to address three gaps. First, the structure and functioning of small-scale fishery markets and relations. Second, how benefits are distributed in the market and affected by trade relations. Third, I examine how relations and benefit distributions influence fishing behaviour. Case studies are used throughout this thesis drawing on empirical work done in Zanzibar, Tanzania and Iloilo, Philippines. The role of global seafood markets is additionally recognised as a driver of change in all four papers of the thesis. Paper I shows that extending the value chain to combine economic and informal exchanges identifies a wider range of fishery-related sources for human wellbeing within seafood trade. It also highlights more marginal players. Paper II demonstrates how actor's abilities to access economic benefits are impacted by local gender roles and social relations. But these intersect with their value chain position and end-markets. In Paper III local norms appear to play a role in fishing behaviour, more so than market incentives. These dynamics are explored through behavioural economic experiments. Finally Paper IV examines how patronage can have contradictory influences for fisherfolk vulnerability and adaptability. It can also create tensions for overall system resilience when considered at different scales. Overall the thesis contributes to a better understanding of the local to global drivers and interactions in small-scale fisheries trade. The thesis also provides insights into some of the factors influencing the distribution of fishery-related benefits. These aspects have all been cited as vital for designing strategies for improving the wellbeing of people reliant on fisheries.