Apo Reef two lagoon systems, the north and south lagoons which are bounded by narrow reef platforms. It is a almost triangular northern and southern atoll-like reefs separated by a deep channel that is open to the west. The channel runs east to west from deep with a fine white sand bottom, numerous mounds and patches of branching corals under the deep blue water. The north lagoon is an enclosed triangular coral reef platform partly exposed during low tide. It is relatively shallow with depths of about . While the south lagoon is an inverted triangular coral platform enclosed on two sides
Lihou Reef National Nature Reserve Lihou Reef National Nature Reserve Lihou Reef National Nature Reserve is a former marine protected area covering an area of 8440 kmin the Australian Coral Sea Islands Territory that was incorporated into the new Coral Sea Commonwealth Marine Reserve in December 2012. Together with the Coringa-Herald National Nature Reserve, from which it is separated by about 100 km of open ocean, it forms the Coral Sea Reserves Ramsar Site, designated on 16 August 2002, listing it under the Ramsar Convention as a wetland of international importance. Lihou Reef and its cays were discovered by Lieutenant John Lihou, R.N., on 23