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. 2016 Apr 5;113(14):3767-72.
doi: 10.1073/pnas.1518509113. Epub 2016 Mar 14.

High-seas Fish Wars Generate Marine Reserves

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Free PMC article

High-seas Fish Wars Generate Marine Reserves

Guillermo E Herrera et al. Proc Natl Acad Sci U S A. .
Free PMC article

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.

Keywords: fisheries management; game theory; marine protected areas; marine reserves; spatial bioeconomic model.

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.
Fig. 1.
Distribution of stock u(ξ) and fishing effort ifi(ξ) over space (ξ). In A–J, =3.5; in K–T, =6. For A–E and K–O, c0=0.01; for F–J and P–T, c0=0.1. The numbers of states are (A, F, K, and P) 1, (B, G, L, and Q) 2, (C, H, M, and R) 10, (D, I, N, and S) 100, and (E, J, O, and T) infinite (open access). Locations of binding reserves are highlighted in red, and nonbinding reserves are in blue. For all panels, c1=0.01, and δ=0.03.
Fig. 2.
Fig. 2.
(A, D, G, and J) Total effort (blue) and stock size (green), (B, E, H, and K) rent, and the fraction of habitat that is (C, F, I, and L) unfished (blue) and in binding reserves (green) as functions of the number of states. Values under open access conditions are indicated by stars. Note that, by definition under open access, rents are completely dissipated (i.e., equal to zero), and therefore, no stars are shown in B, E, H, and K. Each column corresponds to parameter choices (habitat size and cost per unit effort) in Fig. 1. For all panels, c1=0.01, and δ=0.03.
Fig. S1.
Fig. S1.
The distribution of stock u(ξ) and total fishing effort f(ξ)=ifi(ξ) over space (ξ) when interference costs are low. In AJ, =3.5; in KT, =6. For A–E and K–O, c0=0.01; for F–J and P–T, c0=0.1. The numbers of harvesters are (A, F, K, and P) 1, (B, G, L, and Q) 2, (C, H, M, and R) 10, (D, I, N, and S) 100, and (E, J, O, and T) infinite (open access). Locations of binding reserves are highlighted in red, and nonbinding reserves are in blue. For all panels, δ=0.03, and c1=0.001. Compare with Fig. 1, in which interference costs are higher (c1=0.01).
Fig. S2.
Fig. S2.
Effect of discount rate on the distribution of stock u(ξ) and total fishing effort f(ξ)=ifi(ξ) over space (ξ). In AJ, =3.5; in KT, =6. For A–E and K–O, c0=0.01; for F–J and P–T, c0=0.1. The discount rate-δ is (A, F, K, and P) 0, (B, G, L, and Q) 0.03, (C, H, M, and R) 0.3, or (D, I, N, and S) 3. As the discount rate becomes large, the distributions of effort (solid lines) and stock (dashed lines) approach the (E, J, O, and T) open access solutions. Locations of binding reserves are highlighted in red, and nonbinding reserves are in blue. For all panels, h=2, and c1=0.01.

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