Effect of marine reserve establishment on non-cooperative fisheries management

Abstract

Introducing effective marine reserves is a critical issue in fisheries management and marine ecosystem conservation. In recent years, a number of marine reserves or no-take marine protected areas (MPAs) have been implemented worldwide, and some MPAs have shown ecological and economic benefits. However, consideration for coordinated competition between institutions, a central for successful resource management, is often omitted in research on effective MPA management. Given increasing discussions on implementing MPAs in the high seas, where international fisheries often exemplify the tragedy of the commons, understanding potential competition between institutions can affect MPA management. With this in mind, we aimed to gain generic insight into non-cooperative fisheries management with MPAs. Specifically, we explored the effect of MPA establishment on (1) competition strength between fishery institutions, (2) fish population abundance resulting from the competition, and (3) distribution of the gross fishery profit between institutions. To approach these questions, we developed a minimal model that accounts a non-cooperative behavior of fishery institutions and population dynamics under the MPAs management. We demonstrate that, given a small price-to-cost ratio, a prominent increase in fishery competition could occur as a result of introducing an MPA, leading to reductions in fisheries profits and fish population abundance, and greater unevenness in distribution of the gross fishery profit. Intensified fishery competition was typically observed in the case where the rate of population exchange between the fishing grounds and the MPA is not large, and the fraction of the MPA is intermediate, suggesting that regulation agreements will be required to coordinate the competitive harvesting.

Long-Term Conservation Effects of Protected Areas in Stochastic Population Dynamics

“…where E[x] represents the average of x. This model is discussed, for example, in Takashina et al (2017) and Takashina (2020) with some arrangements.…”

Long-term conservation effects of protected areas in stochastic population dynamics

“…(3). With multiplying by n 1 both sides and summing over all probabilities, we recover a deterministic two-patch dynamics (Appendix A.2) discussed, for example, in [32,33] with some arrangements.…”

“…where E[x] represents the average of x. This model is discussed, for example, in [40,41] with some arrangements.…”

On the spillover effect and optimal size of marine reserves for sustainable fishing yields

“…The two-patch model also allows us to examine different migration modes (Amarasekare, 2004), such as positive/negative density-dependent, as well as density-independent migration. This simple approach yields analytical results by introducing an aggregated model when the migration rate is sufficiently larger than the growth rate of a target species (Iwasa & Andreasen, 1987;Auger, de La Parra & Poggiale, 2008;Bensenane, Moussaoui & Auger, 2013;Takashina & Mougi, 2015;Takashina, Lee & Possingham, 2017). The aggregated model allows us to derive conditions for optimal reserve size, fishing yield, and total population size under management with the optimal reserve fraction.…”