Hahajima is the second-largest island of the Ogasawara Islands south of the Japanese main island chain. It is about in area with a population of 440. The highest points are Chibusayama,, approximately, and Sakaigatake,. The largest island of the group, Chichijima is located approximately to the north. Together with nearby smaller islands like Anejima and Imōtojima and Mukōjima, Hahajima forms the Hahajima Rettō, or in former times, the "Baily Group". The island is within the political boundaries of Ogasawara Village, Ogasawara Subprefecture, Tokyo, Japan.
History
The first European discovery of the Ogasawara Islands is said to have taken place in 1543, by the Spanish explorer, Bernardo de la Torre. Hahajima was originally called Coffin Island or Hillsborough Island and settled by Europeans before becoming part of Japan. In World War II, the Japanese government removed the locals and fortified the island; it was the target of several attacks by US forces during World War II. What is left of the defense works is now one of the tourist attractions of the island. The island can be reached by ferry in about two hours from Chichijima. The economy of Hahajima is based on commercial fishing, as well as a state-run rum distillery. Today Hahajima has a population of 450, but the population was 1,546 in 1904 and 1,905 in 1940. There is one road from the village of Kitamura at the north end of the island to the village of Okimura - formerly "Newport" at the southern end of the island, where the harbor is located.
Hahajima is of considerable interest to malacologists because of its endemicland snailfauna, including the eponymous Lamprocystis hahajimana. Due to the widespread presence of invasive species including goats and rodents, flatworms and the rosy wolfsnail, it was feared that many of the endemics had become extinct. But most if not all of the endemic land snail species seem to persist on the remote Higashizaki peninsula on the eastern coast. This is a quite pristine expanse of ground, scenic but very hard to reach. It consists of sheer seacliffs surrounding a plateau with Chinese fan palm, pandanus and broadleaf forest, and appears to be untouched by invasive species at present. It has been proposed that access to the area should be monitored, so that visitors will not inadvertently contribute to destroying this unique area.
Snails
All of these snails are endemic at least to the Ogasawara Islands.
Boninena callistoderma - Endangered, now restricted to Hahajima and nearby Anejima
Among birds, the Bonin white-eye, a gaudy-colored passerine, seems to occur nowhere else anymore than on Hahajima. The extinct Bonin grosbeak is sometimes said to have occurred in the Hahajima Group, but this seems not to be true. Columba janthina nitens, the Ogasawara subspecies of the Japanese wood-pigeon, used to occur on Haha-jima. While it is not precisely known when it vanished from this island, the taxon apparently became completely extinct during the 1980s, but was rediscovered in 1998.
