Ashmore and Cartier Islands

Asmore and Catier Islands.

Ashmore and Cartier Islands
off the Western Australian Coast.
© Geoscience Australia

The Territory of Ashmore and Cartier Islands is made up of the West, Middle and East Islands of Ashmore Reef as well as Cartier Island and the surrounding 12 nautical mile Territorial sea. The islands are uninhabited, small, low and composed of coral and sand, with some grass cover.

The Territory is located on the outer edge of the continental shelf in the Indian Ocean and Timor Sea approximately 320 kilometres off Australia's northwest coast and 170 kilometres south of the Indonesian Island of Roti. The proximity of the Territory to Indonesia has been the subject of joint official discussions in recent years and a Treaty aimed at settling a number of maritime boundaries between the two countries was signed in 1997. The extent of the 12 nautical mile Territorial sea around the Islands is indicated by the two enclosing boundary lines on the map below.

Ashmore Reef

Location of Ashmore Reef.

Ashmore and Cartier Islands.
© Geoscience Australia

Ashmore Reef is 840 kilometres west of Darwin and 610 kilometres north of Broome at 122°59'E, 12°11'S and comprises a shelf-edge reef system of approximately 583 square kilometres, rising from the westward limit of the Sahul Shelf. The West, Middle and East Islands of Ashmore Reef are within the reef rim. They have a combined area of 1.12 square kilometres, the largest being about one kilometre long.

Indonesian fishermen visit Ashmore Reef each year under a Memorandum of Understanding signed by the Australian and Indonesian Governments, which allows them to utilise areas of the sea they have accessed traditionally for centuries. The first recorded European sighting of the reef was on 11 June 1811 by Samuel Ashmore, who named the nearby Hibernia Reef after the ship. During the 1850s American whaling ships operated in the region and during the later half of the nineteenth century, phosphate mining was carried out on West Island.

Ashmore Reef and Islands.

Ashmore Reef and Islands.
© Geoscience Australia

The reef boasts high species and habitat diversity with 14 varieties of sea snake, 433 species of mollusc and 70 fish species identified in the area, along with 255 varieties of coral. The islands also have significant marine turtle nesting areas and migratory bird populations, while dugong, various cetacions and whale sharks are sighted regularly around the reef. The plant communities are mainly shrubland and herbland, with luxuriant growth during the wet season in sharp contrast to the dry season when there is a layer of dead plant material over much of the islands. To protect the reef, the Australian Government declared the Ashmore Reef National Nature Reserve in 1983.

Cartier Island

Cartier Island is located in the West Sahul region of the Indian Ocean at 12°31'50.8" S, 123°33'18.8" E. The island is about 300 kilometres off Australia's Kimberley coast, 200 kilometres south of the Indonesian island of Roti and 70 kilometres from Ashmore Reef. The surrounding reef flat rises steeply from the surrounding depths. Cartier Island is an unvegetated sand cay at the centre of the reef.

Cartier Island and reef.

Cartier Island and its
surrounding reef area.
© Geoscience Australia

Cartier Island is 70 kilometres east of Ashmore Reef in the West Sahul region of the Indian Ocean at 12°31' S, 123°33' E. The island is about 300 kilometres off Australia's Kimberley coast and 200 kilometres south of the Indonesian island of Roti. The reef flat surrounding Cartier Island rises steeply from the surrounding depths to an unvegetated sand cay at its centre.

The Cartier Island Marine Reserve covers 167 square kilometres over an area within a 7.2 kilometres radius of the centre of the island. The Reserve protects the unique and vulnerable ecosystems of Cartier Island and surrounding reefs which are high in biological diversity including 547 identified species of fish, which represent about 16 percent of Australia's fish species. Like Ashmore Reef, Cartier Island and its surrounding reefs have been visited by Indonesian fisherman for centuries collecting birds, bird's eggs, clams, holothurians (sea cucumber), shells, turtles and turtle eggs for consumption and trade on the Asian market.