The herring stock in the Celtic Sea collapsed in 2004. The stock is managed under the European Union's (EU) Common Fisheries Policy (CFP), but with a large measure of local stakeholder involvement through the Pelagic Advisory Council and a local Irish stakeholder committee. An iterative process, initiated by the local committee culminated in a formal rebuilding plan, which ran until 2012, by which time, the stock had fully recovered. Subsequent analyses of stock development over this period suggest that the stock was already recovering by the time the final plan was implemented. Did the stock rebuild by good fortune or did the governance measures put in place achieve their aims? This question is answered by way of examination of stock trends over time, analyses of the main elements of the rebuilding measures, including a management strategy evaluation (MSE) along with analyses of the legal and institutional arrangements in Ireland and in the EU CFP, including the development of the Pelagic Advisory Council. Important innovations in the CFP are revealed as having been crucial for the rebuilding process.