PNAS – Proceedings of the National Academy of Sciences of the United States of America
http://www.pnas.org/content/early/
(Accessed 19 March 2016)

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High-seas fish wars generate marine reserves
Guillermo E. Herreraa, Holly V. Moellerb, and Michael G. Neubertb,1
Author Affiliations
Edited by Alan Hastings, University of California, Davis, CA, and approved January 29, 2016 (received for review September 17, 2015)
Significance
Marine reserves—areas where fishing is prohibited—have been implemented to conserve fish stocks and their habitats. They have been established in near-shore fisheries, where a single state (or “sole owner”) regulates the distribution of fishing effort. Modeling has shown that, under some conditions, the sole owner may also use closed areas to maximize sustainable profit. Here, we show that reserves may also play a role in fisheries management on the high seas, where a limited number of states compete in a noncooperative fishing game. Our theoretical analysis complements recent empirical studies of high-seas protected areas and is relevant in other management contexts characterized by a limited number of harvesters.

Abstract
The effective management of marine fisheries is an ongoing challenge at the intersection of biology, economics, and policy. One way in which fish stocks—and their habitats—can be protected is through the establishment of marine reserves, areas that are closed to fishing. Although the potential economic benefits of such reserves have been shown for single-owner fisheries, their implementation quickly becomes complicated when more than one noncooperating harvester is involved in fishery management, which is the case on the high seas. How do multiple self-interested actors distribute their fishing effort to maximize their individual economic gains in the presence of others? Here, we use a game theoretic model to compare the effort distributions of multiple noncooperating harvesters with the effort distributions in the benchmark sole owner and open access cases. In addition to comparing aggregate rent, stock size, and fishing effort, we focus on the occurrence, size, and location of marine reserves. We show that marine reserves are a component of many noncooperative Cournot–Nash equilibria. Furthermore, as the number of harvesters increases, (i) both total unfished area and the size of binding reserves (those that actually constrain behavior) may increase, although the latter eventually asymptotically decreases; (ii) total rents and stock size both decline; and (iii) aggregate effort used (i.e., employment) can either increase or decrease, perhaps nonmonotonically.