The lagoons and tropical coral reefs of New Caledonia are an outstanding example of highly diverse coral-reef ecosystems and form one of the three most extensive reef systems in the world. They contain the most diverse concentration of reef structures found anywhere in the world, with an outstanding variety of coral and fish species, habitats ranging from mangroves to sea-grasses, and a vast range of reef structures extending across steep ocean slopes. Intact ecosystems can still be found, with healthy populations of large predators as well as a great number and diversity of large fish species. The lagoons are of spectacular natural beauty. They contain reefs of different ages, from live to fossilized coral, providing important information about the natural history of Oceania.
Criterion (vii): Superlative natural phenomena of outstanding natural beauty. The tropical lagoons and coral reefs of New Caledonia are among the most beautiful reef systems in the world due to the great diversity of structures and formations found in a relatively restricted area. They include two double-barrier reefs, deep-water reefs and atolls, and there are also reticulated reef formations close to the shore on the west coast. The distinctive rich and diverse landscape and coastal backdrop is of outstanding natural beauty. But this beauty is not just on the surface, as the reefs contain a spectacular diversity of corals, together with massive arches, caves and fissures.
Criterion (ix): Ongoing biological and ecological processes. The reef complex in this serial property is unique in that it is free-standing in the ocean and surrounds the island of New Caledonia, and is exposed to a wide variety of ocean aspects, notably both warm and cold currents. It has a wide variety of forms, including the main types of reef, from fringing reefs to atolls, as well as ecosystems associated with both coastal and ocean settings. It extends over steep ocean slopes and is one of the best examples in the world of the ecological and biological processes underlying the lagoons and ecosystems of tropical coral reefs, which are themselves amongst the most ancient and complex of ecosystems.
Criterion (x): Biological diversity and threatened species. The property is a marine site with outstanding diversity and habitats ranging from mangroves to sea-grasses with a vast range of reef forms. The barrier reefs and atolls of New Caledonia are one of the three largest reef systems in the world, and the largest in Oceania with those of Fiji. They have the most diverse concentration in the world of reef structures, with 146 types based on the world classification system, equalling or even surpassing the much larger Great Barrier Reef in its diversity of coral and fish. They are home to numerous threatened species of fish, turtle and marine mammals, including the third largest population of dugongs in the world.