Economic Quantification of Delaying Management in the Midriff Islands, Mexico

The Gulf of California has been historically characterized by high levels of marine biodiversity and productive small-scale fisheries. These characteristics are threatened by overfishing. Enhanced marine management is needed to reverse ecological degradation and sustain the ecosystem’s capacity to provide goods and services, including vital fisheries. Marine reserves are a management tool that close off areas of the ocean to fishing, allowing fish inside the reserves to increase in size and number. Theoretically, spillover occurs when fish move across the boundary of a reserve where fishers can benefit. Comunidad y Biodiversidad (COBI) presented a marine reserve network design to the Mexican government in 2015 that would protect 5% of the Midriff Islands. To date, the marine reserve network has not been implemented.

Trade-offs associated with marine reserves are believed to have played a key role in the network’s delayed implementation; potential long-term gains in sustainable fishing and the conservation of biodiversity likely generate short-term losses in fishery revenue due to fishery closures. The trade-offs between conservation and livelihood led our team to ask: What are the consequences of delaying the implementation of a reserve network, and how much area should be protected to enhance both fish biomass and catch?