Inventory of benthic marine algae, hermatypic corals, the main invertebrates and fish, as well as habitat typology in the context of putting the Northern lagoon of New Caledonia on the world heritage site list. The cruise had two main objectives: 1- Inventories: a- establishing the most exhaustive possible inventory of seaweeds and marine phanerogams and hermatypic corals of the large Northern lagoon in New Caledonia and of the Entrecasteaux reefs for which few data are available. The Entrecasteaux reefs could not be studied due to particularly bad weather conditions (risk of cyclone Jasper). We therefore abandoned the latter site and focused our efforts on the area of the Belep islands and Cook reef (central part). b- addressing issues of biogeography on the scale of New Caledonia as well as of the Pacific (comparisons with marine flora from Norfolk and Lord Howe Island, Fiji, western and central Tuamotu, Society Islands, Rapa, Hawaii, Wallis and the Great Barrier Reef) c - added to the reference collections and the photo library, which will be used to create the marine algae and phanerogams guide and the New Caledonian corals atlas. 2 - Habitats: a- characterizing and mapping the main habitats from satellite images / b- for each type of habitat, establish inventories of the 4 main groups in the ecosystem (algae, coral, main invertebrates and fish) / c- draw up the specific relationships between habitat and biodiversity. This cruise falls under the Biodiversity of marine fauna and flora of the South Pacific, coral habitats typology.