Nesting populations of sea turtle in Ishigaki Island, Okinawa

Abstract

The current status of the nesting activity of sea turtles in Ishigaki Island, Okinawa, Japan, was investigated. It was revealed that the dominant nesting species was changing from loggerhead turtle, Caretta caretta, to green turtle, Chelonia mydas in the most of the southern part of Japan. The nesting populations were evaluated to be 10-20 females of C. mydas and 3-8 females of C. caretta, annually. On the average, C. mydas re-migrate to nest every 3.7 years. The total number of females in C. mydas nesting population in Ishigaki was estimated to be 75 at most. The minimal estimation was 25, and in this case several females with low nest site fidelity were expected to migrate every year in addition.