Marine Reserve Creation and Interactions between Fisheries and Aquaculture – A Bio-economic Model Analysis

The rapid growth of aquaculture world-wide affects capture fisheries in several ways. We present a bio-economic model to clarify interactions between these two activities, including the effect of a marine protected area (MPA). The aquaculture production is assumed to reduce the intrinsic growth rate of fish, and hence stock size and harvest, while the dispersal from the MPA may limit these effects. This is considered applying both open access and economically optimal management outside the MPA. The results of a numerical simulation show that the wild fish stock in an open access fishery is independent of the aquaculture development, while the wild catch significantly declines. Introducing an MPA, the wild fish stock increases, while the wild catch varies depending on the aquaculture development and the MPA size. With optimal management, the stock size declines for small MPA sizes, but increases for larger sizes, while aquaculture production declines for large MPA size. The harvest and the total profits increase with increasing MPA size. These results show that an MPA may not only compensate for negative effects of aquaculture upon a wild fishery, but may be biologically and economically enhancing under both open access and optimal management regimes as well