Climate regime shifts occur at irregular intervals and have profound and persistent impacts on ocean temperature and circulation patterns and on the dynamics of marine fish populations. Despite a growing scientific literature and some attention to the implications of such regime shifts for domestic fisheries, the issue has received little attention in the context of international fishery management. This paper presents evidence for the significance of climatic regime shifts, and draws upon the recent history of conflict between Canada and the United States over Pacific salmon management to illustrate the dangers that unpredicted, unanticipated environmental regime shifts pose for efforts to maintain international cooperation. This suggests a need for greater attention to this issue. Fishery agreements can be made more resilient to the impacts of such environmental changes by explicitly building in flexibility ï¿½ for example, by allowing the use of side payments. In addition, pre-agreements on procedures to be followed in the event of sustained changes in fish stock productivity or migration patterns, and cooperation on developing common scientific understandings, can help to prevent destructive conflicts. Finally, the literature employing game theoretic shared-fishery models could be further developed to focus on providing practical guidance for maintaining cooperation in the presence of unpredictable and persistent environmental changes.