Palau is part of the Caroline Islands group. It is the westernmost archipelago in Oceania, located 741 km east of Mindanao in the southern Philippines and about 1,300 km southwest of Guam. Palau is composed of 12 inhabited islands and more than 700 islets. The archipelago consists of a clustered island group and six isolated islands which lie approximately 339 to 559 km to the southwest. Palau has numerous island and reef types, including volcanic islands, atolls, raised limestone islands, and low coral islands. A barrier reef surrounds much of the main island cluster, merging into a fringing reef in the south. Palau has the most diverse coral fauna of Micronesia and the highest density of tropical marine habitats of comparable geographic areas around the world. In addition to coral reefs, mangroves, and seagrass beds, Palau has deep algal beds, mud basins, current swept lagoon bottoms, rich tidal channels, and anoxic basins within the rock islands. Many of these environments contain corals.
Palau’s rich marine biota include approximately 400 species of hard corals, 300 species of soft corals, 1400 species of reef fishes, 7 out of 9 of the world’s species of giant clams, thousands of other invertebrates (many still to be identified), the world’s most isolated colony of dugongs (a relative of the sea cow) and Micronesia’s only saltwater crocodiles. Terrestrial species include 1260 species of plants (including almost 200 endemics), 141 resident and migratory bird species (including 11 endemics), 5000 species of insects, and 40 species of freshwater fishes, including at least 4 endemics. Palau has the largest undisturbed forest and largest freshwater lake in Micronesia, and 70 unique marine lakes.