Property Rights to the (Linear) Ocean in Customary International Law

Résumé

I model the ocean as a line, or an array of lines, and show how the most profound change in property rights in human history, creation of the Exclusive Economic Zone, emerged as an equilibrium in customary international law. In a symmetric ocean, I find that customary law codifies efficient Nash equilibria, and steers countries away from inefficient Nash equilibria. The model also identifies the trigger for this change in property rights—access to nearshore fisheries by foreign fleets—and the reason choice of a particular limit, like the current 200-mile zone, is arbitrary. In an asymmetric, regional sea, I find that the scope of the EEZ is determined by the relative power of coastal and distant water states, and need not be efficient. Finally, I find that proposals to nationalize the seas or ban fishing on the high seas are neither efficient nor supportable as equilibria in customary law.