The tiny Pacific islands nation of Kiribati declared the world's largest marine protected area Thursday — a California-sized ocean wilderness that includes pristine reefs and eight coral atolls teeming with fish and birds.

The Phoenix Islands Protected Area, or PIPA, lies about halfway between Hawaii and Fiji and also includes undersea mountains. It will conserve one of the Earth's last intact oceanic coral archipelago ecosystems.

Kiribati Environment Minister Tetapo Nakara said the government wanted to conserve the area's biological diversity.

"The coral reefs and bird populations of the islands are unique, virtually untouched by man — a true wilderness of natural beauty," he said Thursday in announcing the marine reserve.

Nakara said his ministry hopes to fully establish the 164,200-square-mile area as a protected zone by the end of the year with the goal of attracting more tourists to Kiribati — an impoverished coral atoll nation of about 95,000 people. About 50 people live on one of the protected atolls.

The government will regulate all activities within the reserve, including restricting commercial fishing in some areas and boosting enforcement and surveillance. More research will be undertaken to better understand the area's marine ecosystem.

The plan does not come without costs. By restricting commercial fishing in the area, the Kiribati government will forego about 11 percent revenue it gets from foreign commercial fishing licenses.

Kiribati earned $33 million in 2001 from fishing licenses — the latest available figure.

The government stands to lose about $3 million of this revenue with the creation of the reserve, but is hoping to recoup some of the losses by boosting tourism, which now accounts for 20 percent of the gross domestic product.

It has already applied to have the marine reserve listed as a World Heritage Site.

Kiribati and Boston-based New England Aquarium conducted joint scientific research in the area over several years with funding and technical aid from Conservation International.

"Kiribati has taken an inspirational step in increasing the size of PIPA well beyond the original eight atolls and globally important seabird, fish and coral reef communities," Greg Stone, New England Aquarium vice president of global marine programs, said in a statement.

"The new boundary includes extensive deep sea habitat, tuna spawning grounds, and as yet unsurveyed submerged reef systems," he said.

Three aquarium-led research expeditions since 2000 found more than 120 species of coral and 520 species of fish, some new to science.

Stone said the array of fish, sea turtles, and other species demonstrated the pristine nature of the reserve. It is also an important seabird migration route and nesting area.

Conservation International President Russell A. Mittermeier called on governments to support Kiribati's efforts and make similar commitments.

"The Republic of Kiribati has now set a standard for other countries in the Pacific and elsewhere in the world," Mittermeier said in a statement.

Kiribati's total land area covers 287 square miles, spread across 33 coral atolls. Its people are increasingly concerned about coastal erosion, thought to be caused by rising seas in a nation no more than 16 feet above sea level.

Besides destroying causeways and seawalls, rising waters have also begun to topple coconut palms grown along the shoreline that are crucial to islanders' survival.