President Bush will create the world s largest protected marine area today, designating as a national monument a 1,200-mile-long chain of small Hawaiian islands and surrounding waters and reefs that are home to a spectacular array of sea life, senior administration officials said last night.

In his second use of the 100-year old National Antiquities Act, which empowers the president to protect important cultural or geological resources instantly, Mr. Bush will enact a suite of strict rules for the area, including a five-year phasing out of commercial and sport fishing, officials said.

The chain of largely uninhabited atolls, seamounts, reefs and shoals, which sweeps northwest from the big islands of Hawaii, is called the Northwestern Hawaiian Islands and is home to some 7,000 species of marine life, including endangered green sea turtles and Hawaiian monk seals and millions of breeding seabirds.

Earlier yesterday, the region, which at 140,000 square miles is nearly the size of California, was to have been named a national marine sanctuary, a different kind of protection that could have taken a year to enact.

But Mr. Bush, in a last meeting to consider the plan and timetable, decided to cut things short, said a senior official, who spoke on condition of anonymity because he did not want to take attention away from Mr. Bush s public statement today. "He said, Look, I ve got this authority, I m going to use it," the official said.

"What we avoid is another year or more in process when we already have consensus," he said, noting that national-monument status avoided the prospect of lawsuits over proposed sanctuary regulations. Since the Clinton administration, environmental campaigners had pushed for marine sanctuary status for the area, and as recently as early last night they were girding for months of public debate over the proposed sanctuary rules with a few groups representing Pacific fish-processing companies and fishing fleets.

Last night, representatives of the conservation groups were at first startled by the sudden switch, but were then exultant.

"This is really for the first time saying the primary purpose of this area of the ocean is to be a pristine, or nearly pristine, kind of place," said David Festa of a private group. "It would take it off the books as a fishing ground. That s really the first time we ll have done that in any kind of sizable area."

Some environmentalists noted yesterday that the extra protection was an easy call for the administration, in part because there was little significant opposition in Hawaii or Washington. The move could also help the re-election prospects of Linda Lingle, Hawaii s Republican governor, who last fall banned commercial activities in state waters in the area and endorsed the federal sanctuary plan.

They noted that there were only eight commercial fishing boats licensed to fish in the remote islands, and that rising fuel costs had made such trips less and less profitable.

Still, representatives of groups seeking to sustain Pacific fishing activity expressed concern as news of the new designation spread.

Kitty M. Simonds, executive director of the Western Pacific Fishery Management Council, one of eight regional advisory bodies to federal fisheries agencies, said the group planned to fight a complete closing of fishing in the area.

"We supported the sanctuary concept but wanted the continuation of our healthy bottom fisheries up there," Ms. Simonds said in a telephone interview.

The move builds on actions of several previous presidents, notably Theodore Roosevelt and Bill Clinton. In 1909, Roosevelt designated much of the island chain a national wildlife refuge. At the end of his second term, Mr. Clinton issued two executive orders protecting marine resources around the refuge and ordering federal marine agencies to prepare for the marine sanctuary designation.

Jean-Michel Cousteau, the marine explorer and filmmaker, said it was important to ensure that the designation came with meaningful rules and enough money to protect and further study the region s biological resources. He recently spent five weeks filming in the area and showed the resulting documentary at the White House in April.

A senior administration official said the film had a powerful effect on Mr. Bush and Laura Bush. Only once before, in February, has Mr. Bush created a national monument: at the African Burial Ground in Lower Manhattan. Some 400 remains of enslaved and free Africans from the 17th and 18th centuries were discovered there in 1991.

(Por Andrew C. Revkin, The NY Times, 16/06/2006)