Houtman Abrolhos
The Houtman Abrolhos is unusual in having a luxuriant and diverse living coral reef at such a high latitude. 194 species in 50 genera have been recorded there, all but two of which are tropical. This is a surprisingly high coral diversity, considering the high latitude of the reef, and the relatively low diversity of other biota. For a full list, see list of corals of the Houtman Abrolhos.
The Big Breaker
The Big Breaker is the most northerly geographic feature in the Houtman Abrolhos islands in the Indian Ocean off the west coast of Australia. It is located at the extreme tip of a reef that extends about three kilometres north of North Island. Its gazetted location is , but in fact it is located about 270 metres south-east of there, at . It is so named because it is a breaker, a portion of submerged reef over which waves break.