The extension of economic jurisdiction to 200 nautical mile Exclusive Economic Zones or Fishing Limits enabled coastal and island nations to add vast wealth to their exclusively owned natural resource portfolios. Simultaneously, the rights of nations to distant water fisheries were, at best, reduced to privileges. The motives for enclosure were economic, political, and strategic. However, simple economic theory suggests certain potential outcomes. First, if fishery stocks remained constant, restrictions and charges would make fishing in foreign zones relatively more costly, fishing in the remaining high seas less costly, and fishing in the domestic zone possibly less costly. Relative costs also may favor exploitation of coastal and fresh water regions for aquaculture. Second, because stocks do not remain constant, depletion in some areas will alter relative costs. Investments in conservation will be limited to claimed areas, where investors capture the benefits. Third, wherever maritime claims overlap or otherwise are unsettled, international tension will mount. The analysis here demonstrates that these expectations have become reality in the North Pacific.