The world's largest marine protection area has been announced under the presidency of George Bush.

Three areas in the US will be designated as national monuments, including the Mariana Trench and northern Mariana Islands, the Rose Atoll located in American Samoa, and a chain of remote islands in the central Pacific.

Rare fish and bird species, coral reefs and underwater volcanoes will be protected in an area spanning some 505,000 square kilometres in the Pacific Ocean.

The world's largest protected area currently is the Phoenix Island Protected Area, which was established in 2008 by the South Pacific nation of Kiribati.

The last time Mr Bush announced a marine protection area was in 2006, when he declared 363,000 square kilometres of Pacific Ocean near the north-western Hawaiian islands.