Several atolls that make up the Papahanaumokuakea Marine National Monument are named for ships that met their end on the reef there nearly 200 years ago.

Now, an internationally recognized designation promises added protection for the area's delicate ecosystem and the marine vessels that pass through it.

On Thursday, the entire monument, a 140,000-square-mile section of the Northwestern Hawaiian Islands, was named a "Particularly Sensitive Sea Area" by the International Maritime Organization, a United Nations agency concerned with international shipping regulations.

"This puts us on the international map," said 'Aulani Wilhelm, National Oceanic and Atmospheric Administration superintendent for the Northwestern Hawaiian Islands Marine National Monument.

Papahanaumokuakea is only the second marine protected site in the United States and the 11th in the world to earn the designation.

The announcement places the monument with Australia's Great Barrier Reef and the Galapagos Archipelago in a small group of internationally recognized sites marked for special protection.

NOAA applied for the designation in mid-2006, around the time the area was established as a national monument by President Bush, Wilhelm said.

Beginning May 1, special zones called "Areas to be Avoided" within the "Particularly Sensitive Area" will appear on international nautical maps to direct ships away from dangerous areas or places of ecological significance.

The designation does not ban marine vessels from the zone outright, but requires notification from certain kinds of ships passing through the area, including U.S.-flagged vessels and ships involved in developing emergencies.

The reporting area begins 11.5 miles outside the monument's boundaries, and mariners must also announce when they cross into "Areas to be Avoided."

Penalties for ships that do not notify monument managers are still being determined.

The notification system is a big step toward assessing maritime traffic near the monument, Wilhelm said.

"We'll have more information on what's happening out there ... and help mariners understand the special nature of this place and the hazards it poses," she said.

Little data is available on how many ships pass near or through the site, and the area's size alone — it is larger than 46 of the 50 states — makes it difficult to keep track.

"It would be like knowing everything going on in Minnesota," Wilhelm said. "It's on a grand scale."

The U.S. Coast Guard, charged with patrolling the area, makes the 280-mile trip from Honolulu several times a month.

Coast Guard Capt. Charlie Ray announced the designation in Honolulu on Friday and applauded international efforts to recognize "the damage even one ship could cause."

Papahanaumokuakea encompasses 10 islands, atolls, submerged banks, shoals, reefs and their associated waters over 1,200 miles, which is about the distance from Chicago to Miami.

The monument contains 4,500 square miles of coral reefs and is home to more than 7,000 marine species, a quarter of which are found nowhere else in the world.