Historical background, description of the physical environments of Ashmore Reef and eartier Island and notes on exploited species

WA Museum Records and Supplements | Updated 1 decade ago

Abstract: Ashmore Reef (12°17'S, 123°02'E) and nearby Cartier Island (l2°32'S, 123°33'E) are located on tl.e north-western extremity of the Sahul Shelf. They are approximately 350 km off the Kimberley coast of Australia and 145 km from Roti, Indonesia.

The morphology and physical environments of the two reef systems are briefly described as a background to faunal inventories presented in Parts 2-7 of this publication.

Ashrnore Reef (approximately 26 km long and 14 km wide) is similar in general shape and morphology to other shelf-edge atolls off the north-western coast of Australia, but because of the larger breaks in the reef there is no impounding of water in the lagoon on outgoing tides as at the Rowley Shoals and to a lesser extent, Scott Reef. There are three vegetated islets on Ashmore Reef. Cartier Island, an unvegetated sand cay, is surrounded by an oval-shaped reef platform approximately 4.5 km long by 2.3 km wide.

Mean sea surface temperatures range from approximately 24°C in July and August to 30°C between January and March. Spring and neap tidal ranges (semi-diurnal) are 4.7 m and 2.8 m respectively.

Observations on species exploited in the traditional Indonesian fishery are recorded. These suggest that composition and abundance of exploited species at Ashmore Reef and Cartier Island reflect a higher level of fishing effort there than at Scott Reef and Rowley Shoals.