With the great spread and intensification of marine fisheries exploitation, the traditional fisheries regime of free and open access (part of traditional “freedom of the seas”) has been modified by many regional or stock-related management arrangements, and is now undergoing drastic change through a radical extension of coastal state jurisdictions. This article deals mostly with the development of various regional and stock-related arrangements. After sketching the overall purposes of management, the aiticle details some of the differences among competing states which have delayed or limited management arrangements, or otherwise complicated their development. Issues of allocation may be uppermost for competing interests, discussed here in the context of shifts from undivided to divided catch limits. The regulatory powers of intergovernmental fisheries commissions have generally been quite limited. While fisheries scientists have in some cases performed vital roles in encouraging regional arrangements, their information and advice has been of limited scope and influence in securing more restrictive regulatory regimes. FAO's Committee on Fisheries (COFI) might be called a global fisheries commission, though much of its most important work has related to amimating and supporting arrangements of a regional character. The radical shift outward of national jurisdictions is rearranging fisheries exploitation in most parts of the world. Given the nature of the resource, however, some forms of regional or stock arrangements will still be needed if the overall purposes of management are to be realized.