Since the Ogasawara Islands have always been remote, never being adjacent to a continent since they were formed, animals and plants have evolved in their own way there. There are over 100 kinds of indigenous plants and more than 14 kinds of animals that are native to the islands, such as the Ogasawara damselfly, all designated as protected species. Water-eroded high cliffs surround the island making the scenery even more magnificent, and the area is a popular spot for divers. The seawater around Hyotan-jima, Minami-jima and Hira-shima islands, all belonging to the Ogasawara Archipelago, has very high clarity and the sea is full of coral reefs and tropical fish.
More info: http://www.jnto.go.jp/eng/location/regional/tokyo/ogasawarashotou.html