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
Coral Sea Reserves Ramsar Site Geographic Society of Queensland which visited the Herald Cays and their surrounding reef in 1997. The site was designated as a wetland of international importance under the Ramsar Convention on Wetlands. It was listed on 21 October 2002 as Ramsar Site 1222. The site is centred on the Coral Sea Plateau, about 440 km east of Cairns, Queensland, and east of the Great Barrier Reef, from which it is separated by an area of deep water known as the Queensland Trough. Lihou Reef NNR lies to the south-east of the Coringa-Herald NNR and is separated from it by about 100