By generating and explaining facts, science holds an important role in environmental policy decision‐making. However, scientific knowledge is often framed as objective and neutral in policy debates, which can be challenged by stakeholders who have a different view of the issue. To counter this situation, we propose a novel scientific approach to analyze problems that are highly contested and seem difficult to resolve, that is, wicked problems. Our study combined post‐normal science and environmental justice perspectives to shed light on a wicked problem—the largely unsuccessful efforts to rehabilitate yellow perch stocks in Lac Saint‐Pierre (LSP), Quebec, Canada. The combination of these two perspectives allows us to investigate the causes of the decrease of yellow perch stocks and the social and institutional barriers to rehabilitation—which can only be overcome if the injustice perceived by different stakeholders is overcome. Our study presents an approach that addresses uncertainties, integrates various knowledge forms, reassesses decision‐making procedures, and highlights inequalities within a specified territory. The research also underlines the importance of the qualitative dimension in the development of knowledge and the need to address equity in the development of environmental policies.