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Ogasawara NP, Tokyo
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A green turtle with a red Chinese stamp appeared at the center’s beach in 2007. “Miss China” had been rescued from sale for food through a Buddhist release custom; she laid 6 clutches, and satellite tracking revealed an unusual southbound route.
Researchers matched 2 humpbacks by the unique patterns on their tail flukes off both Miyakejima and Chichijima—about 800 km apart—in the same 2022–23 breeding season. It was the first same-season match between those areas.
Green-turtle stew is a celebratory local dish in Ogasawara: Chichijima seasons it with salt, while Hahajima uses soy sauce. The marine center explicitly works to balance this food tradition with turtle conservation.
In 2021, islanders spotted a young green turtle off Nishijima trapped in a red beer crate and unable to dive. The center treated the 10-kg turtle until it recovered and could return to the sea.
At town-side Omura Beach, hatchlings can follow streetlights instead of the sea. The center moves eggs to its hatchery only after temperature has determined their sex, then releases the babies at darker beaches at night.
A female may lay 4–5 clutches of about 100 eggs each, roughly 2 weeks apart, in a single season. Then she typically won’t return to Ogasawara to nest for another 2–4 years.
In 2024, about 60 people surveyed 22 Chichijima beaches 167 times and counted roughly 1,700 nests, up from about 450 in 2001. To confirm hidden nests, teams probe the sand with an iron rod.
Ogasawara’s turtle-raising program began in 1910, long before the marine center opened. It ran until 1939, restarted under Tokyo’s fisheries station in 1973, and was later taken over by the center.
Baby turtles may hatch underground 4–7 days before emerging. Once their clutchmates are ready, they wriggle together and shift sand downward to climb toward the surface, often coming out after sunset as the sand cools.
A snorkeler encountered a tagged yearling about 10 days after the center had released it from the same beach. The center traced the tag to identify the turtle—an unusually quick glimpse of its life back in the wild.
The green turtle’s name refers to the greenish hue of its body fat, not its shell. Adults graze mainly on seagrass and seaweed, while hatchlings eat a more varied, omnivorous diet.
Every 2–3 weeks, staff and volunteers scrub algae from young turtles’ shells. In tanks they can’t rub against rocks or coral as wild turtles do, so this small bit of hands-on care helps keep them healthy.
