Vanatinai in the context of "Copra"

A reef is a ridge or shoal of rock, coral, or similar relatively stable material lying beneath the surface of a natural body of water. Many reefs result from natural, abiotic (non-living) processes such as deposition of sand or wave erosion planing down rock outcrops. However, reefs such as the coral reefs of tropical waters are formed by biotic (living) processes, dominated by corals and coralline algae. Artificial reefs, such as shipwrecks and other man-made underwater structures, may occur intentionally or as the result of an accident. These are sometimes designed to increase the physical complexity of featureless sand bottoms to attract a more diverse range of organisms. They provide shelter to various aquatic animals which help prevent extinction. Another reason reefs are put in place is for aquaculture, and fish farmers who are looking to improve their businesses sometimes invest in them. Reefs are often quite near to the surface, but not all definitions require this.

Earth's largest coral reef system is the Great Barrier Reef in Australia, at a length of over 2,300 kilometres (1,400 miles).

The Louisiade Archipelago is a string of ten larger volcanic islands frequently fringed by coral reefs, and 90 smaller coral islands in Papua New Guinea.

It is located 200 km southeast of New Guinea, stretching over more than 160 kilometres (99 mi) and spread over an ocean area of 26,000 square kilometres (10,000 sq mi) between the Solomon Sea to the north and the Coral Sea to the south. The aggregate land area of the islands is about 1,871 square kilometres (722 sq mi), with Vanatinai (Sudest) beingness the largest.