Leandro Castello’s research program focuses on the ecology and conservation of fish and fisheries in relation to global change processes, with particular attention to tropical regions. Key topics of investigation are the impacts on fisheries caused by overfishing, pollution, hydrological alteration, and land cover change. Unlike programs based on specific topics, his program focuses on a broad range of fishery problems, seeking to identify research questions for which the answers have the potential to improve the state of affairs for fish resources and fishing communities. This goal is achieved by pursuing questions that can influence policy and adopting an interdisciplinary approach. This research program on fish and fisheries ecology and management often includes humans, adopts an ecosystem-based perspective, and makes use of various approaches from fields other than fish biology and fisheries science, including ethnobiology, resource governance, and policy analysis, among others.