Ashmore Reef & Cartier Island
Located in the Timor Sea some 320 km off the Kimberley coast of Australia, on the edge of the Australian
continental shelf (in an area known as the Sahul Shelf), lie the three reef systems of Ashmore Reef, Cartier
Island and Hibernia Reef. Ashmore Reef and Cartier Island together form an External Territory of Australia.
Ashmore Reef is the larger of the three and is separated from Cartier Island by 53 km of open ocean and from
Hibernia Reef by 42 km.
Ashmore Reef is a large platform reef consisting of an atoll-like structure with three low, vegetated islands, numerous banks of shifting sand and two large lagoon areas. The surrounding reef consists of a well-developed reef crest — most prominent on the south and east sides — and a broad reef flat that can be up to 3 km across. The three islands located within the lagoon — West Island (32 ha), East Island (16 ha), and Middle Island (13 ha) — are mostly flat, being composed of coarse sand with a few areas of exposed beachrock and limestone outcrops. West Island is the largest of the islands being about 1 km long.
The only other island in the region is that of Cartier Island, located 67 km southeast from Ashmore Reef. Cartier Island is an unvegetated sand cay sitting at the centre of a reef platform that rises steeply from the sea bed. The island and its surrounding reefs are protected by the Cartier Island Marine Reserve which covers an area of 167 km².
Both Ashmore and Cartier are protected marine reserves: the Ashmore Reef National Nature Reserve was established in 1983 and the Cartier Island Marine Reserve in 2000. The reserves help to conserve regionally and internationally important species of marine turtles, dugongs, birds (both migratory and seabird species) as well as their prolific and unusual diversity of sea-snake species. The reefs (particularly Ashmore Reef) support the greatest number of coral species of any reef off the West Australian coast.
In this region are also a number of shoals, banks and reefs that are at all times submerged. These include the Johnson Bank (located 27 km southeast from Ashmore Reef) with an area 137 km², Woodbine Bank (48 km southeast from Ashmore Reef) covering 93 km², Marlin Bank (12 km to the northwest of Ashmore Reef), Vee Shoal (94 km northeast from Ashmore Reef), Wave Governor Bank (6 km southeast from Cartier Island), Fantome Bank (73 km northeast from Cartier Island) and Barracouta Reef (54 km east from Cartier Island). Several large, unnamed, deep-water banks are also found within the area: Shoal A, Shoal B and Shoal C.
