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Effective MPAs: Essential tools for strengthening ocean health

© Conservation International/photo by Keith Lawrence

It is now undeniable that marine protected areas (MPAs) provide a very powerful tool to make oceans healthier.  Unfortunately, not enough area has been protected and most of the existing MPAs don’t work as well as they could for national or global benefits to yet be fully realized. 

Areas designated as MPAs are intended as refuges from overfishing and habitat destruction, and can also serve as sources to support or replenish fisheries, biodiversity and other ecological and economic benefits outside their boundaries. By supporting healthier natural communities inside their boundaries, they can also provide a buffer against other pressures that affect coastal marine areas worldwide, such as pollution, climate change, and invasive species. More than 10,000 MPAs exist, but only about 2.3% of the world’s oceans are fully protected from extractive activities, compared to the Convention on Biological Diversity’s goal of protecting 10% by 2020. Many scientists and the 2003 World Parks Congress recommended that the ultimate goal should be 30%. Most protected areas are actually only partially protected, allowing a range of human uses, including many types of fishing.

© Conservation International/photo by Sterling Zumbrunn

Even in fully protected MPAs, a key problem is that many are too small to protect most species. For very large MPAs, such as the huge remote MPAs created in the last decade in the Hawaiian Islands, Phoenix Islands, Cook Islands and elsewhere that make up about 60% of currently protected marine area, effective enforcement rather than size is the main problem.  Some of the largest MPAs have been created by small island nations that lack the money, ships and other resources needed to patrol oceanic areas up to 1 million sq. km or more.

 As these cases show, mere designation of an area as protected accomplishes little.  A recent study of 87 globally-distributed MPAs (Edgar et al. 2014) identified  five features necessary for success: full protection (no take), effective enforcement, age greater than 10 years, area greater than 100 sq km , and location isolated from other areas by deep water or sand.  Unfortunately, MPAs needed four or five of those features to be effective.  Those with three or less provided essentially no conservation value and were not ecologically distinguishable from fished sites.

© Keith Ellenbogen

Those features will be important guides for creating the many more—and more effective-- MPAs that will be needed to reach the goal of protecting a minimum of 10% of representative ocean ecosystems.  Choosing appropriate sizes and locations will satisfy the key geographical requirements, especially if networks of ecologically related areas can be configured.  Establishing and enforcing full no-take protection is harder, because it requires political leadership and money.  Leadership must be strong and visionary, because although the costs of protection are immediate, the benefits are not.  Benefits usually only begin to appear after marine populations rebound, which can often take 5 or 10 years.  Presidents and ministers who create MPAs and manage them properly are making an investment in the future health of their countries’ citizens---both human and marine.   

For that reason, time may be the most important of the five key features identified by Edgar and his colleagues.  Absent protection, marine populations are more robust now than they will be in the future, so protecting them now will provide the strongest foundation for MPA success.  Equally important, since MPAs need at least 10 years for their benefits to become significant, the sooner they are created, the sooner those benefits will flow.

Benjamin S. Halpern
Professor, Bren School of Environmental Science and Management
UCSB, Santa Barbara, CA

Chair in Marine Conservation, Imperial College London
Grand Challenges in Ecosystems and the Environment

Director, Center for Marine Assessment and Planning (CMAP)

Senior Fellow, UN Environment Programme- World Conservation Monitoring Center (UNEP-WCMC)

Research Biologist, National Center for Ecogical Aanalysis and Synthesis