Large-Scale Study of MPAs Identifies Key Features of Successful Reserves

Photo copyright Leighton Wallis

Photo copyright Leighton Wallis

A brief perusal of this website uncovers numerous case studies highlighting the ecological and economic successes of MPAs. However, compilations of data from a large number of studies worldwide can showcase the true potential of MPAs in ways smaller-scale studies cannot, as well as helping resource managers to identify common elements crucial for MPA success.

The adoption and establishment of MPAs is increasing exponentially around the world, but questions remain as to how these conservation measures are translating into on the ground (or rather, under the water) benefits. Earlier this year, 25 scientists from around the world published the most comprehensive review to-date comparing fish communities inside and outside of MPAs. Using information from over 170,000 underwater surveys performed by volunteer divers with the Reef Life Survey program, the scientists assembled a massive dataset containing details on 964 sites located inside and outside of 87 MPAs spanning one-third of the world’s marine ecoregions.

The “Coral Triangle”, a portion of the Western Pacific that includes the waters surrounding the island nations of the Philippines, Malaysia, and Papua New Guinea, hosted the highest number of fish species. However, large fishes (>250mm) were more common in isolated islands than in those where fishing occurs. This is potentially because fishing targets large fish over smaller species. The remote areas of French Polynesia and the Line Islands had the greatest biomass of large fish as well as large numbers of heavily fished sharks, groupers, and jacks. Many of the MPAs in this study are inadequately enforced, but MPAs still showed improvements as compared with fished areas. This trend may be driven by the extraordinarily high abundances of fished species in remote protected areas that are removed from human population centers and thus experience less fishing pressure. On average, MPAs contained 36% more species of large fish, 35% more large fish, and 101% more sharks.

The scientists identified 5 key features of successful MPAs, which they dubbed “NEOLI”: No-take reserve, well Enforced, Old (at least 10 years), Large (> 100 km2), and Isolated from other suitable habitat. MPAs with only 1 or 2 NEOLI features were not distinguishable from fished areas, but those with at least 4 showed high levels of recovery.

MPAs with all 5 NEOLI features showed a 224% increase in fish biomass; over a 800% increase in large fish, grouper, and jack biomass; and a nearly 2000% increase in shark biomass, however less than 5% of the MPAs in this study had all 5 features. Still, there is an opportunity for growth. Given sufficient political will to enforce protections for existing MPAs, expand the number of “no-take” MPAs, and extend MPA boundaries to fully encompass suitable habitat, even small MPAs can deliver important conservation benefits as they mature. More emphasis is needed on better MPA design, enforcement and committed management for MPAs to be effective.

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