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
Coringa-Herald National Nature Reserve Coringa-Herald National Nature Reserve Coringa-Herald National Nature Reserve is a former nature reserve in Australia’s Coral Sea Islands Territory that was incorporated into the new Coral Sea Commonwealth Marine Reserve in December 2012. The former nature reserve together with the Lihou Reef National Nature Reserve is part of the Coral Sea Reserves Ramsar Site. Its extent is also within the Coringa-Herald Reefs Important Bird Area. The reserve lies to the east of the Great Barrier Reef and covers an area of 8,860 km, most of which is open water. It contains three pairs of islets and cays, the Herald Cays,