What is the difference between a barrier reef and a fringing reef around New Caledonia?

Around New Caledonia, the primary difference between a fringing reef and a barrier reef lies in their proximity to the landmass and the presence of a lagoon.12

• Fringing Reefs: These consist of flat reef areas that directly skirt the coastline of the mainland. In New Caledonia, a fringing reef borders the central part of the west coast of the main island.231
• Barrier Reefs: These reefs are separated from the landmass by a lagoon or channel, which is often approximately 50 metres (160 feet) deep. Most of New Caledonia's main island is enclosed by a true barrier reef that extends from the north to the south, creating a large lagoon between the reef and the shore.231

While fringing reefs are attached directly to the coast, the barrier reef system creates a distinct, protected body of water that is a defining feature of the New Caledonian marine environment.12