The global seafood industry is a vital source of food, income, livelihoods, and culture. Seafood demand is steadily rising due to growth in the global human population, affluence, and per capita consumption. Seafood supply is also growing, despite declining wild fish stocks, with phenomenal advances in aquaculture, that is, the cultivation of aquatic organisms. Aquaculture supplied 42 % of the world’s fish in 2012 and is forecast to eclipse capture fisheries production by 2030. The balance between these two seafood production (...) systems has profound implications for global food security, income distribution, and ecological sustainability. Here, a qualitative analysis of the ethics and sustainability of capture fisheries and aquaculture is presented. An innovative practical ethics approach is introduced which adapts the ethical matrix, a conceptual tool for analyzing the wellbeing, autonomy, and justice of different interest groups, and Rapfish, a rapid appraisal technique used to evaluate the sustainability of fisheries along six performance modalities, including ethics. Using case studies of global large- and small-scale capture fisheries and generalized carnivorous and omnivorous aquaculture systems, I show that human institutions and social actors interact in complex governance processes to influence seafood ethics and sustainability. (shrink)