Middleton Reef is one of two reefs comprising the Elizabeth and Middleton Reefs Marine National Nature Reserve. This nature reserve was additionally declared a Ramsar Wetland of International Importance. Middleton is one of the southernmost open-ocean coral reef platforms in the world and the peak of one of the volcanic seamounts which form the Lord Howe Island volcanic chain. Only a small sand cay exists, but the few Common Noddies that breed at the reserve do so on one of the wrecks. The reef is some 555 kilometers due west of the Australian coast and some 220 kilometers north of Lord Howe. This remote location of Middleton and the combination of cold currents in winter and warm currents in summer have brought forth a number of endemics –it contains the last known large population of black cod and more than 300 tropical and subtropical fish species have been registered. The sea here is a nursery habitat for open-water fish and the area around Middleton and towards Elizabeth Reef has been declared a Sanctuary Zone where neither commercial nor recreational fishing is allowed. Although already seen and named in 1788, the kidney-shaped reef still poses a danger to vessels and shows a number of shipwrecks.