2024 Activity Report on the Ogasawara Islands, a World Natural Heritage Site

Since its opening in 2012, Sumida Aquarium has been collaborating with Ogasawara Village to promote this World Heritage Site in Tokyo. In September 2023, a new information center, "Ogasawara Base ," will be established and renovated as the " Ogasawara " area, connected to the Ogasawara Sea Life . This marks the start of a new initiative.
Aquariums have the role of conveying information about the ocean, nature, and animals. In order to convey the beautiful nature of the Ogasawara and pass it on to the future, we would like to work in cooperation with the local area to comprehensively disseminate information from Ogasawara , an urban area where animals can visit anytime, about the living creatures and the environment that surrounds them, the local industry and tourism that coexist with this World Natural Heritage Site, and environmental issues.
In 2024, we utilized this area to carry out a variety of activities.

(1) Sumida Bonin Island

June is a special month for Ogasawara , marking the return of the Ogasawara to Japan (June 1968) and their inscription as a World Heritage Site (June 2011). To mark these milestones, Sumida Aquarium hosted its first event since the opening of " Ogasawara Base," sponsored by Ogasawara Village. The Ogasawara were formerly known as uninhabited islands ("buninjima") and Bonin Island in English-speaking countries. The event's name, "Sumida Bonin Island," was inspired by the name of the Ogasawara. This event, held from June to July 2024, recreated a landscape familiar to those who have visited Chichijima Island. Exhibiting familiar trees from the Ogasawara Islands, the space allowed visitors to experience the Ogasawara atmosphere even more than usual.

Inside the museum during the exhibition

Ogasawara Base tree display

In addition to the spatial design, the event also featured the concept of "Ogasawara with all five senses," with an exhibition of tactile nuts delivered directly from Ogasawara Village, the opportunity to experience the aroma of seasonal passion fruit, the sale of island cheese dogs reminiscent of the tropics, a lecture on local green sea turtles by staff from the certified NPO Everlasting Nature*, and a musical performance of Ogasawara Ogasawara songs.

Touchable nut exhibit

Experience the scent of seasonal passion fruit

Island cheese dog that evokes a tropical atmosphere

A lecture about local green sea turtles by staff from the certified NPO Everlasting Nature*

Ogasawara folk song performance

*Sumida Aquarium is participating in the Sea Turtle Joint Breeding Program, which is organized by Everlasting Nature, a certified NPO that operates the Ogasawara Marine Center, owned by Ogasawara Village.

(2) Green sea turtle conservation activities

The Ogasawara are the largest nesting ground in Japan for green sea turtles, which are designated as an endangered species. Sumida Aquarium has previously taken in 40 baby green sea turtles from Chichijima and Hahajima, raising them for about a year until they reach a size where they are less susceptible to predation, and then the animal care staff have released them back into their native seas.
Sumida Aquarium not only raises baby green sea turtles, but also cooperates in ecological research on green sea turtles. Baby green sea turtles that are kept in our care are fitted with living tags. These are important tags that indicate the decade in which they were born in Ogasawara.

The white spots on the back shell are living tags

1. Baby green sea turtles "Bonin" and "Blue",
Grow up healthy and head to the sea of ​​your hometown, Ogasawara!

The two calves we took in in 2023, Bonin and Blue, have grown from a carapace length of 7.7cm to 21.3cm (Bonin) and 8.2cm to 21.5cm (Blue), respectively.
Until they are returned to the sea, I feel a mixture of relief that they can be safely returned to their home sea, and sadness and joy at the thought that they will now be living in this vast ocean.
However, contrary to these feelings, Bonin and Blue headed straight for the sea from the beach and began swimming. In the water, they moved powerfully with their front legs, occasionally popping their heads out of the water to take a breath as they moved forward. The staff swam alongside them from behind for a while to observe, but they were swimming so skillfully that it was almost impossible to keep up with them.
After the two horses were safely returned to the sea, I remember feeling a sense of relief as I gazed out at the deep, rich blue "Bonin Blue" ocean. At the same time, I'll keep this a secret: my tension eased and I was overcome by a sudden feeling of fatigue.

animal care staff releasing the Ogasawara turtle Bonin back into the waters of Ogasawara

The sea of ​​Ogasawara where Ogasawara have returned

The "blue" of green sea turtles returning to the sea

2. Welcome to "Heart" and "Rock"!

A new baby born in 2024 has joined the Ogasawara Base family. Every year, the baby's name is chosen by fifth graders at Ogasawara Village Ogasawara Elementary School, based on the theme "The charm of Ogasawara that we want to share." This year, after much discussion, the baby was given the lovely names "Heart" and "Rock," derived from the Chihiroiwa (Chihiro Rock) in the Ogasawara(nicknamed Heart Rock).
Heart and Rock were born on August 5, 2024. When they arrived at Sumida Aquarium, their carapace lengths were 7.2cm and 7.3cm, respectively.
Both of them quickly got used to the environment at Sumida Aquarium and started eating their food.
Perhaps because Heart has a laid-back personality, feeding time approaches slowly, but Rock, upon noticing, rushes over with great impatience. We wonder how these two will fare from the time we take them in until they are safely released back to their home sea, and whether they will grow up healthy. It's the start of another new year.

Green Sea Turtle "Heart" and "Rock"

Naming board written by students of Ogasawara Elementary School

The name comes from Chihiro Rock (nicknamed Heart Rock)

Exchange with Ogasawara Elementary School

Not only do the students from Ogasawara Elementary School name the green turtles, but they also watch over the baby turtles as they return to the sea and hold special classes to explain about the green turtles they have looked after. We interact with the students throughout the year.
The fifth-graders at Ogasawara Elementary School in 2023 gave the two adorable names "Bonin" and "Blue." Through these names, we were able to raise awareness among many people about "Bonin Blue," the color of Ogasawara's endlessly clear, deep blue sea." As a thank you for their support, we also donated plates made from upcycled plastic collected during beach cleanup activities. This year's plates include the birthdays of Bonin and Blue, as well as the dates they returned to the sea. Looking back at the plates even after graduating from elementary school, we hope that the children will remember the time they spent together at the aquarium teaching about the nature of their hometown, and that they will always remember the importance of cherishing that nature.

Plate for 2024

Donating the plates

Heart and Rock entering the tank for the first time at the unveiling ceremony

Staff column on first trip

The nature I experienced there was magnificent and beautiful, and I was once again captivated by this "World Natural Heritage Island." I went to both the mountains and the sea, and I felt firsthand that there is nature that is unique to this island, right in the places closest to me. The color of the sea, "Bonin Blue," from which the names "Bonin" and "Blue" are derived, was many times more beautiful and gorgeous than I had imagined. This time, in addition to Chichijima, I also visited Hahajima. Hahajima has about one-fifth the population of Chichijima, and it is also an island where the islanders have strong connections with each other. While there, I visited Minamizaki and Chibusayama, and was able to experience the magnificent nature and unique ecosystem.
In addition to our main activity of releasing a baby green sea turtle back into the sea and caring for a new one, we also participated in a small cleanup. Our aquarium held a beach cleanup on Chichijima Island in April of this year (Column: Cleaning up green sea turtle nesting grounds again this year! "Ogasawara Beach Cleanup" ), and during this trip, a beach cleanup event was held, with Sumida Aquarium lending a hand. Seeing the floating trash reflected in the beautiful natural scenery below reminded me of the reality of someone in need and the importance of environmental coexistence. This trip inspired me to continue introducing the beauty of nature and animals, as well as continuing to work to solve environmental challenges and spread the word. We hope to continue this spirit through the "Heart" and "Rock" we welcomed this time.

Participating in a beach cleanup on Hahajima

The magnificent nature of Hahajima

The beautiful sea of ​​Hahajima

About the Ogasawara area

Following the registration of the Ogasawara as a World Natural Heritage Site in 2011, Sumida Aquarium opened in 2012 with the aim of "introducing the world-class natural environment beneath Tokyo Skytree®, a landmark that Japan is proud of," and has continued to collaborate with Ogasawara Village ever since.
The Ogasawara Sea Life, a symbol of the museum, was built with the cooperation of local divers and other related parties, and recreates the underwater scenery of the Ogasawara , including the "endlessly clear, deep blue color of the sea" known as "Bonin Blue" and underwater reefs. This aquarium is home to approximately 450 animals of 45 species, including sand tiger sharks, a animals that is representative of Ogasawara , as well as schools of yellowed barracudas and striped snappers that often appear in the surrounding waters.

Ogasawara Sea Life

Ogasawara Base