New Study Offers Guidance for Compounding Investment in Oceans
Many marine protected areas (MPAs) have been established worldwide to safeguard a range of coastal habitats and species. Almost all of them allow navigation and recreational activities like snorkeling, diving and surfing. Many allow some types of fishing. A much smaller number, called marine reserves, are closed to all fishing, drilling and other extractive activities. Now, a new study reported in the journal Nature illuminates what makes for a well-designed and managed MPA that offers a significant boost to ocean species and ecosystems.
The question is important because when an MPA works well, the results can be astounding. The study found, for example, that protected areas meeting four or five criteria for effectiveness, including no-fishing provisions, had 14 times the biomass of sharks as fished areas and five times more big fish like grouper and jacks. Healthy populations of species high on the food web—like sharks and big fish—play a crucial role in balancing marine ecosystems and maintaining their diversity. Those results matter to all of us not just because it means better fishing opportunities, but because healthy, resilient oceans are the life support system of our planet. Well-designed nearshore protected areas can boost recreation and tourism economies and serve as living laboratories for learning and stewardship.
Protected areas can also help us understand the impacts of fishing and the imprint we leave on the oceans. By using long-established, effective protected areas as a reference point, the new study estimates that fishing has reduced the biomass of large fish on temperate and tropical reefs by 80% and sharks by 93%. The magnitude of those losses suggests many ocean species face a risk of extinction. Fishing clearly exerts tremendous pressure on ocean life.
The study takes a big leap forward in defining which factors make an MPA highly effective. These include a size greater than 100 km sq, no-take provisions, good enforcement, long-term duration, and inclusion of the whole reef or other habitat feature being protected. Meeting four or five of these criteria is like getting compound interest on a savings account: the benefits of the MPA grow exponentially as these factors accumulate.
Conversely, the study found that MPAs meeting only one or two of the criteria—true for 59% of the world’s MPAs--perform no better than similar unprotected areas.
There’s a compelling message here: in the effort to restore our beleaguered oceans, we can’t ignore the critical importance of sound design and good management of MPAs. There’s no instant fix.
These criteria are guidelines, not absolutes, and my experience diving in marine parks around the world and helping design California’s new network of MPAs bears that out.
For example, size clearly does matter. In fact, the study shows that the benefits can be orders of magnitude higher for big marine reserves (100 km sq or more) that also meet two or three other criteria. Few protected areas match the productivity of large preserves like those around the Galapagos Islands. Yet smaller marine reserves can be quite effective at achieving specific objectives, especially when other factors are well met. According to Ed Parnell, one of the authors of the MPA paper, “the medium-sized MPAs established in California are not really big enough to protect large pelagic species, most of which are high-level predators. But these areas likely provide important protection for the more residential species such as rockfish and lobsters, and are thus important for the functioning of those nearshore communities. This study shouldn’t impede the planning of smaller, carefully designed reserves.”
Around the Channel Islands off the Southern California coast, 12 reserves averaging about 75 km sq each support more kelp, more abundant fish populations and larger lobster than similar fished areas. Cabo Pulmo National Marine Park in the Sea of Cortez covers only 70 km sq yet teems with life, with a 5-fold increase in biomass and a remarkable diversity of species after 15 years of protection. The fact that these examples meet at least three other criteria helps make them effective despite their smaller size.
Another consideration is that sometimes criteria that can’t be met at the establishment of a marine reserve can be met over time. Many successful reserves originally met fewer than four or five criteria. It takes time to get the word out to visitors and previous users of a new protected area and to fund, assemble, and train enforcement personnel. That process often begins with public concern about compliance; students, parents and teachers took an innovative approach to raise awareness of compliance problems at the Whangarei Harbor Marine Reserve in New Zealand by forming a human chain around the reserve’s borders. At Cabo Pulmo, snorkel and dive operators (often former fishermen) do most of the work to ensure compliance, with occasional visits from a Park enforcement vessel. In California, nonprofits, local government groups, and state agencies are working together to install signs, deliver presentations, and walk the beach to promote compliance in places like Monterey, Los Angeles and San Diego. Initial lack of enforcement resources—or of certain other features—shouldn’t deter establishment of a marine reserve. Instead, initial limitations should be addressed as quickly as possible over time.
Secretary of State John Kerry recently called for protection of 10 percent of the world’s coastal waters in marine reserves (.08% of the ocean was in no-take reserves in 2008). The U.S. itself has made progress toward that goal, yet no-take MPAs cover less than 3% of the nation’s ocean waters, according to NOAA, and most of that surrounds Pacific islands. The U.S. could exert valuable leadership by applying the criteria identified in this study to expand the benefits—and range—of our own protected areas.
Declaring an area protected is clearly not enough to make it effective. But it’s a good start. This study shows that with a combination of clear objectives, science-based design, and strong compliance, we can get there. And even if it takes time to bring all the pieces together, the benefits to ocean health, fisheries, and local economies are worth the effort.