On July 22, 2025, two green sea turtles that had been on display in the "Ogasawara Sea 4" tank in the "Tokyo Sea" area of Tokyo Sea Life Park were moved to the Ogasawara Islands. This was because the tank had become too small for the two turtles as they grew.

This green sea turtle was brought in from Haha-jima Island in the Ogasawara Islands on September 25, 2023. At the time of arrival, its shell length was approximately 6.4 cm and its weight was approximately 46 g, but by the time of departure, it had grown to approximately 43 cm and weighed approximately 10 kg!


Preparations for removal
They headed to the Ogasawara Islands by boat, and after their health was checked, they returned to the sea. We can only hope that they will grow up healthy in the waters around Ogasawara.


A green sea turtle returning to the waters of the Ogasawara Islands (Photo courtesy of Yoshiaki Shimojo)
Then, on July 27th, two new green sea turtles arrived from Haha-jima Island in the Ogasawara Islands.


Newly brought-in sea turtles
Like other animals, green sea turtles cannot be put on display immediately after being brought in. They need time to acclimate to their environment and food, and pass parasite tests.

The newly arrived green sea turtles were small, with a shell length of about 6 cm and a weight of about 45 g, so we had to feed them in small pieces.


Finely chopped sardines and sakura shrimp. The sakura shrimp have been peeled to prevent choking.
We were worried whether the newly brought-in green sea turtles would eat the food, but contrary to our concerns, they started eating right away.

Afterwards, the green sea turtles got used to the food and environment, and successfully passed the parasite test, and on August 20th, we finally reopened the exhibit of the green sea turtles in the small tank of "Ogasawara Sea 4," which can be seen from the second-floor corridor!


Green sea turtles swimming in a small tank
Immediately after being put on display, it seemed unfamiliar with the tank, swimming towards the outside and getting stuck in narrow gaps, but recently it seems to have gotten used to it, and we often see it floating leisurely.

As of September 10th, its shell is about 10cm long and its weight has increased steadily to about 170g. The amount of food it eats has also increased from the initial 5g to more than three times that amount, now at 17g. It can now eat sakura shrimp with the shell on, and we have also started giving it sweet shrimp and horse mackerel, which are a little harder than sakura shrimp and kibinago.


Finely chopped sweet shrimp, sardines, sakura shrimp, and horse mackerel. The variety and quantity have increased compared to the first batch.
Once they've grown to a certain size, they'll make their debut in the main tank on the first floor. These green sea turtles will continue to grow bigger and bigger, so please watch them grow!

[Tokyo Sea Life Park]

◎Related articles
・ Congratulations on the World Natural Heritage designation! "Ogasawara Islands Field Report 3" (July 8, 2011)
・ Green sea turtles – proper feeding is crucial for their growth! (January 14, 2022)
・ Green sea turtles – feeding techniques are crucial for their growth! Part 2 (August 26, 2022)

(September 26, 2025)