A marine protected area, or MPA, is a section of the ocean where human activities are regulated for the long-term conservation of marine life. Similar to national parks on land, these designated regions are set aside to give marine ecosystems a chance to recover and thrive. MPAs can be established by local, national, or international authorities and come in many forms, from wildlife refuges to research facilities, each with different levels of protection.
Revitalizing Ocean Ecosystems
Within an MPA, reducing human pressures like fishing and mining allows marine ecosystems to recover. This protection increases the quantity and size of marine organisms, known as biomass. Studies of 87 MPAs worldwide found that fish biomass inside no-take reserves was, on average, 670% greater than in similar unprotected areas.
The benefits extend beyond just the number of fish. In well-managed MPAs, overall species diversity often increases as habitats are restored. For example, in New Zealand’s Cape Rodney-Okakari Point Marine Reserve, the seafloor, once dominated by sea urchins, has shifted to a thriving kelp forest. This change is attributed to the increased abundance of predators like snapper and rock lobster, which control urchin populations and allow kelp to regrow.
This recovery is also visible in other habitats. On the Great Barrier Reef, research has shown that MPAs had lower incidences of coral disease, suggesting that reducing physical injuries to corals from fishing activities makes them less vulnerable. By providing a sanctuary from direct human impact, these areas allow the ecosystem’s natural balance to return, supporting a wide array of species.
Supporting Sustainable Fisheries and Tourism
The ecological recovery inside MPAs generates economic and social benefits beyond their boundaries. One of the most documented outcomes is the “spillover effect,” where the increased abundance of marine life within a protected area leads to individuals migrating into adjacent waters. This movement replenishes fish populations in nearby fishing grounds, benefiting local communities.
A study of a California MPA, for instance, found that while the protected area reduced the available fishing grounds by 35%, the sustainable catch rate in adjacent areas increased by 245%. Similarly, research on large-scale MPAs showed that catch rates for tuna fisheries increased by an average of 12% to 18% in waters near the protected zones. In the Philippines, some local communities reported a 150% increase in their catch rates in areas surrounding marine sanctuaries.
Beyond fisheries, healthy marine ecosystems in MPAs are draws for tourism. Activities like snorkeling, scuba diving, and wildlife watching attract visitors, generating revenue and creating local jobs. The Great Barrier Reef Marine Park in Australia, for example, generates over $5.4 billion annually from tourism and supports approximately 64,000 jobs. This activity provides livelihoods for tour guides and hospitality workers, creating a sustainable economic model that supports coastal communities.
Bolstering Coastal and Climate Resilience
Marine protected areas enhance the resilience of coastal communities and the global climate. Intact coastal ecosystems sheltered within MPAs, such as mangrove forests, salt marshes, and coral reefs, serve as natural buffers. These habitats absorb wave energy and reduce the impact of storm surges, providing a line of defense for shoreline communities against erosion and flooding.
These ecosystems also help mitigate climate change through “blue carbon” sequestration. Coastal habitats like seagrass meadows and mangroves capture and store atmospheric carbon dioxide in their biomass and the sediment below. Studies have found that seagrasses can capture carbon up to 35 times faster than terrestrial forests, making their protection a valuable strategy to reduce greenhouse gases.
By safeguarding these blue carbon ecosystems, MPAs help ensure that stored carbon remains locked away. For instance, one study in Indonesia calculated that MPAs prevented the loss of approximately 14,000 hectares of mangroves over a decade. This avoided the release of an estimated 13 million metric tons of carbon dioxide equivalent emissions.
Creating Living Laboratories for Science
Marine protected areas serve as natural laboratories for scientific research and education. Inside these zones, scientists can study marine ecosystems with minimal human disturbance. This allows them to establish a scientific baseline of a healthy ocean, which is important for measuring the impacts of threats like climate change and pollution elsewhere.
Researchers use these living laboratories to investigate everything from species interactions to the effects of climate change on marine life. In Mexico, biologists have used MPAs to document how protected fish populations grow larger and more numerous compared to those in fished areas. In the deep waters of the Gulf of Mexico, remotely operated vehicles explore protected vents to learn about organisms that thrive without sunlight. These studies provide insights that inform conservation strategies worldwide.
These protected areas also help raise public awareness of the marine world. Many MPAs support educational tourism and citizen science programs, allowing the public to learn about marine conservation firsthand. By acting as successful examples of ocean protection, they inspire public support for conservation and help cultivate environmental stewardship.