In the last two decades, networks of marine protected areas (MPAs) have been created at a rapid rate around the world. Because MPA locations are often difficult to change once established, the design process is a crucial step for achieving successful networks. Here we develop spatially explicit bioeconomic models of seven nearshore fisheries in Southern California which integrate data on fish life history and demography, the distribution of habitat, regional oceanography and fishing fleet behavior. We use these models to estimate the value of MPAs relative to other management approaches and also explore how the choice of MPA locations determines their effectiveness as a conservation tool and their impact on adjacent fisheries. Finally, we explore alternative methods for network design, comparing the outcome of haphazard, guideline-based, and model based approaches.
Results/Conclusions
We find that while strategically placed MPAs have great potential as a management tool, haphazardly placed MPAs have much narrower utility. Although they increase the population sizes of harvested species, they do this much less effectively than strategically designed networks. Haphazard design is even more problematic for economic outcomes, often reducing fishery profit in situations where better designed networks could have improved profit. Surprisingly, rules of thumb intended to guide MPA placement do little to improve expected conservation and fisheries outcomes. We propose an alternative approach that will consistently outperform a guidelines-based process, while preserving stakeholder involvement in MPA network design.