Victory at sea: the world's largest protected area established this year in the remote pacific, points the way to restoring marine ecosystems.(OUR IMPERILED OCEANS)

AT FIRST SIGHT, THE PEOPLE OF Kiribati, a nation of tiny islands in the central Pacific, would not appear to be model conservationists. Trash is abundant all along Tarawa, the capital island, a skinny atoll shaped like a backward L and crammed with 40,000 people. (It was the site of one of the costliest landings in World War II, in which 1,000 U.S. marines were killed.) The rustic charm of the traditional thatched houses, which have raised platform floors and no walls, is offset by the smell of human waste wafting from the beaches. The groundwater is contaminated. Infant mortality is high, life expectancy low. And yet this past January impoverished Kiribati established the world's largest protected area, a marine reserve the size of California.

It surrounds the Phoenix Islands, a remote, largely unpopulated archipelago 1,000 miles east of Tarawa. The 158,000-square-mile Phoenix Islands Protected Area, covering about 12 percent of Kiribati's watery domain, holds some of the world's most pristine coral reefs as well as a great abundance and diversity of tropical marine life. And it's the first reserve to place such a large area of open ocean off-limits to commercial fishing. The reserve is one of the planet's ecological bright spots, the boldest, most dramatic effort to save the oceans' coral reefs, the richest habitat in the seas. No wonder the I-Kiribati (pronounced ee-kiri-bahs, which is what the people call themselves; the country is pronounced kiri-bahs) want to showcase the reserve as a uniquely unspoiled center for marine science, recreational diving and eco-tourism.

Though coral reefs cover less than half a percent of the oceans' area, they host more than 25 percent of its fish species. The first worldwide assessment of coral reefs, released this summer, showed that a third face extinction due to climate change, disease, pollution and overfishing. Australia has outlawed fishing along a third of the Great Barrier Reef to stem the decline of fish stocks there. Palau, a prime scuba-diving destination in the western Pacific, has created a series of no-take areas to protect its healthiest reefs, which amount to a third of its coastline. Other Pacific island governments agreed to do the same, in what they dubbed the "Micronesia Challenge. "The Bahamas, Dominican Republic, Jamaica and St. Vincent and the Grenadines, all of whose waters are severely overfished, have responded with a "Caribbean Challenge," which will set aside a fifth of their waters for coral and fish recovery.

In the United States, the largest protected area is the Papahanaumokuakea Marine National Monument, established in 2006 around the Northwestern Hawaiian Islands. It's about 140,000 square miles, larger than all the other U.S. …