Extinction of the naturalized fresh water turtle in Chichijima-Island of Ogasawara (Bonin) Islands, South Japan

Abstract

Fresh water turtles were investigated from 22 to 25 September 1999 in Chichi-jima Island (27°05'E, 142°13'N) of Ogasawara (Bonin) Islands, South Japan. The methods used were traping, observation of basking and hearing from the residents. Native species do not inhabit this island, and all the species confirmed until now are invaded ones. As the result, no turtle was observed and captured in all the water areas. There was no evidence that foods in the traps were eaten. Thirty-seven residents among forty-six (80.4%) observed fresh water turtles in this island before three to four years ago, but never in the last two years. From these facts it must be certain that the fresh water turtles in Chichi-jima Island became now extinct by the environmental change, though they once established there.