Do you like fish curry or grilled shrimp? If so, marine protected areas (MPAs) are good news for you. That’s because fish — and other marine animals and plants — that are threatened by thousands of tons of plastics, pesticides and toxins that pollute our oceans are being protected in MPAs. When fish ingest toxins released by plastic refuse, the toxins enter the food chain, endangering animals and humans alike. But MPAs give us a chance to keep sections of the ocean free of plastic debris, allowing ocean habitats and the species they support to recover and thrive.

Scuba diver near coral (© Ethan Daniels/Shutterstock)
A diver explores a coral reef in Palau. Eighty percent of the island nation’s territorial waters are protected. (© Ethan Daniels/Shutterstock)

Some MPAs allow regulated fishing or recreation, while others ban it completely. MPAs have been established along coastlines, around coral reefs, islands or mainland fisheries, and far from any land at all. All protect a broad range of marine life and habitats.

Scientists estimate that to safeguard our natural marine resources, 30 percent of the world’s oceans should be protected. Today about 3 percent is adequately protected. But by designating MPAs along their coastlines and in deep ocean areas, countries and international organizations can increase the percentage of protected ocean.

World map showing marine protected areas (Courtesy of World Database on Protected Areas)
Global marine protected areas (Courtesy photo)

How do they work?

MPAs along coastlines help maintain mangrove and cypress swamps, coral reefs and other natural barriers. They protect the shore land from hurricanes, and shelter marine plants and animals.

MPAs also bring economic benefits. The fishing industry prospers when there are more fish to catch. Coastal marine sanctuaries attract tourists who help support local economies. Scientific monitoring and enforcement of MPA rules creates additional jobs.

Good news for lobster lovers

In the United States, California’s network of 124 MPAs shows what can be done. California, with a coastline of almost 1,800 kilometers, completed its coastal network of MPAs in 2012, creating more than 120 underwater refuges that extend from Oregon to Mexico.

“As safe havens, underwater parks offer a home and refuge for big, old, fat, female fish to recover, grow and replenish our oceans,” according to the nonprofit group California MPAs. Around California’s Channel Islands, where MPAs have been in place for 10 years, a 2012 study found that lobsters were more abundant and larger in protected areas, with an average of five more legal-sized lobsters caught per trap inside the MPAs than in nonprotected waters.

Seascape photo (© deb22/Shutterstock)
Australia’s Great Barrier Reef marine park is the world’s largest coral reef ecosystem. It covers 344,400 square kilometers. (© deb22/Shutterstock)

The most successful network of MPAs is around Australia’s Great Barrier Reef, says Woods Hole Oceanographic Institution scientist Simon Thorrold. “We’ve got some of the best evidence there in terms of protections,” he says. “It is a multiuse reserve: About 30 percent of the reefs are no-take reserves, and the rest have different levels of protection.”

Another possible MPA benefit occurs when adult fish migrate beyond MPAs and repopulate areas where their population has been depleted. Scientists call this “spillover.”

Spillover may be key to repopulating the rest of the oceans. “If at some point we get CO2 emissions under control and we start to reverse that, then we’ve got areas that can potentially seed other areas,” Thorrold says.

Bird flying above many birds on beach (© AP Images)
A sooty tern on the nesting colony at French Frigate Shoals, in the Hawaiian Islands, part of the Pacific Remote Islands Marine National Monument. (© AP Images)

Upholding the rules

A sanctuary is only as good as its enforcement. Monitoring MPAs is a huge task. Drones and satellite technology can observe and document illegal fishing. Monitoring the health of marine ecosystems is a bigger challenge. For that, Thorrold says, “You’ve got to be on the water. You’ve got to be sampling in the water.”

Surveillance, interdiction and prosecution of offenders all are necessary and all are expensive. The island republic of Palau, with 80 percent (500,000 square kilometers) of its waters designated as protected areas, set up a crowdfunding campaign to help finance MPA enforcement.

The United States is now home to the world’s largest marine protected area, Papahanaumokuakea Marine National Monument, and it remains committed to ocean conservation.

Baby turtles crawling in sand (© AP Images)
Kemp’s ridley sea turtle hatchlings head for the water at Padre Island National Seashore, Texas. (© AP Images)

What can you do?

Download our free poster on marine life.