President Bush created a vast new marine sanctuary on Thursday, extending stronger federal protections to the Northwestern Hawaiian Islands and the surrounding waters with their endangered monk seals, nesting green sea turtles and other rare species.

The nation's newest national monument covers an archipelago 1,400 miles long and 100 miles wide in the Pacific Ocean. It's home to more than 7,000 species, at least one-fourth of them found nowhere else.

"To put this area in context, this national monument is more than 100 times larger than Yosemite National Park," Bush said. "It's larger than 46 of our 50 states, and more than seven times larger than all our national marine sanctuaries combined. This is a big deal."

Click here for FOXNews.com's Natural Science section.

Creation of the nation's 75th national monument was announced at a White House ceremony. The decision immediately sets aside 140,000 square miles of largely uninhabited islands, atolls, coral reef colonies and underwater peaks known as seamounts to be managed by federal and state agencies.

Bush said he drew inspiration from a documentary on the island chain's biological resources shown at the White House in April by Jean-Michel Cousteau, the marine explorer and filmmaker. Over dinner that night, Bush said he also got "a pretty good lecture about life" from marine biologist Sylvia Earle, an explorer-in-residence at the National Geographic Society.

In introducing the president, first lady Laura Bush quoted Mark Twain, who once described Hawaii as "the loveliest fleet of islands that lies anchored in any ocean."

Conrad C. Lautenbacher, head of the National Oceanic and Atmospheric Administration, which will manage nearly all of the protected area, said, "It's the single largest act of ocean conservation in history. It's a large milestone."

"It is a place to maintain biodiversity and to maintain basically the nurseries of the Pacific," he said. "It spawns a lot of the life that permeates the middle of the Pacific Ocean."

It is only the second time that Bush has invoked the 1906 National Antiquities Act, which gives the president authority to create national monuments to preserve the nation's ancient cultural sites and unusual geological features. The law itself turned 100 this month.

The president had planned as late as Wednesday to use instead the National Marine Sanctuary Act, a law that would allow challenges from Congress and others to the decision.

"As we drew closer and closer to our target to propose a marine sanctuary, and coupled with his great experience with Jean-Michel Cousteau and Sylvia Earle, he realized that we had the consensus, that we had run the process, and the time was right to just get the job done," said James Connaughton, chairman of the White House Council on Environmental Quality.

Designating the area as a national monument takes immediate effect, Connaughton said, and the government doesn't have to wait to begin a five-year phaseout of the eight or nine commercial fishing permits in the area and to impose strict prohibitions on any other extractive uses.

In February, Bush used the antiquities law for the first time when he declared part of the African Burial Ground in the lower Manhattan section of New York City a national monument. The site, covering less than half an acre, marks where an estimated 20,000 slaves and free blacks were buried in the 18th century.

President Clinton used the act to create 19 national monuments and expand three others to set aside 5.9 million acres of land, mainly in the West, and he drew widespread criticism from conservatives.

About 132,000 square miles of the marine area that is being set aside for the national monument already is designated either a coral reef ecosystem reserve or a national wildlife refuge. By making it a national monument, the government will have greater power to protect it.

Expanding the existing reserve and refuge to a monument of 140,000 square miles will make it the largest no-take marine conservation area in the world, just ahead of the Great Barrier Reef in Australia.

Midway Atoll, one of the outermost points of the new monument, will retain an emergency landing strip for commercial and military trans-Pacific flights.

NOAA will manage all of the monument except for two national wildlife refuges within it that will still be overseen by the Fish and Wildlife Service. Last month, state and federal officials signed an agreement to manage the pristine islands jointly.

Administration officials say their intent is to preserve zoned access for native Hawaiian activities, educational and scientific expeditions. Recreational and tourist visits that are no more harmful than scuba diving or photography also will be allowed. Permits, however, will be required for all activities.

Joshua Reichert, who heads the private Pew Charitable Trusts' environment program which pushed for the sanctuary for eight years, said the region contains almost 70 percent of the tropical shallow water coral reefs in the United States.

"When you add it all up, it's a world-class ecological jewel," he said. "From both a national and global perspective, this really is a landmark conservation event."