The policy studies literature is divided on how information processing takes place in policy processes. Punctuated equilibrium theory claims that policymakers tend to process information disproportionately, giving more weight to some incoming signals than to others. By contrast, thermostatic models of policymaking argue that policymakers respond in a more proportionate way. In this paper, we analyse information processing in the adoption of Total Allowable Catches (TACs) under the European Union’s (EU) Common Fisheries Policy. Based on a novel measure for the proportionality of information processing, it shows that over time TACs have become more closely aligned with incoming signals about fish stocks. This development can be explained through a combination of changing discourses around fisheries conservation and institutional adjustments in EU fisheries policy. This analysis has implications for the debate between punctuated equilibrium and thermostatic models of policymaking and our understanding of the effectiveness of EU fisheries policies