This chapter provides a value chain approach to understand how the agency of firms and workers are structured by both inter-firm power relations and 'extra-transactional' actors and institutions, and their implications for social and environmental sustainability in seafood production. It emphasizes the importance of understanding the wider political economy of decision-making around both the environmental and social sustainability of fisheries and aquaculture production. The seafood industry, comprised of capture fisheries, aquaculture and their supporting value chains, plays a major role in the economy and society of Southeast Asia. The multi-sited nature of the seafood industry means that abuses of labor are possible at multiple value chain nodes, falling under the control of a variety of interlinked but often separate actors. Beyond international regulatory approaches, regional governments and the wider development community also need to engage in reducing the causes underlying longer-term, persistent vulnerabilities across Southeast Asia's seafood sector.