The legal and political difficulties of managing fish stocks that straddle both national waters and the high seas were not abolished by the introduction of exclusive economic zones. Here leading scholars of international law and international relations explain the wave of bitter disputes that arose in the 1990s over such straddling stocks. They show how regional responses to those challenges shaped the negotiation of a 1995 UN Fish Stocks Agreement and helped strengthen the global high seas fisheries regime. Keen attention is paid to whether and how evolving regimes meet the scientific, regulatory and compliance-related tasks of effective management - and the significance of regime interplay in this regard. Certain developments in international fisheries law, particularly crucial to effective management of high seas fisheries, are examined: reconceptualization of the freedom of the high seas; legal measures to control the harvesting of vessels flying flags-of-convenience; the dispute settlement apparatus; and emerging procedures for compliance-control activities by others than the flag state. These global developments are related to six regional case studies featuring management of straddling stocks in the Grand Banks off Canada, the Southern Ocean, the Doughnut Hole of the Bering Sea, the Peanut Hole of the Okhotsk Sea, the Loophole of the Barents Sea, and the Banana Hole of the Northeast Atlantic.