Full compliance with harvest regulations yields ecological benefits: Northern Gulf of California case study

Summary 1. The Northern Gulf of California is an ecologically important marine area with a high degree of biodiversity, endemism and productivity. Mounting conservation concerns have prompted researchers to propose new management regulations, restricting fishing and protecting sensitive species. Compliance with existing regulations is poor. Rules that are currently in place, if followed, may go a long way towards achieving the ecological goals of management. 2. We conduct a review of existing fisheries regulations in this area. Then, using a spatially explicit marine ecosystem model (Atlantis), we estimate the benefits of compliance with existing fisheries regulations. 3. Under a full compliance scenario, we find large increases in protected species biomass within 25 years and a slowed rate of ecosystem degradation because of fishing. However, full compliance costs the fishing industry about 30% of its annual revenue. 4. We parse out the benefits offered by management instruments (including spatial management protections, seasonal fishery closures, gear restrictions, cessation of illegal fishing and vessel buy-out programmes) and conclude that a suite of measures is needed to address major conservation objectives. 5. Synthesis and applications. This exercise quantifies the benefits of improved fisheries enforcement and provides a benchmark by which the value of future regulatory amendments can be assessed. Where compliance with existing regulations is poor, conservation goals may be better served by strengthening enforcement than by enacting new rules and legislation.