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Ryukyu’s Mountain Turtles – Interview with Okinawa Turtle Centre’s Aya Narukiyo

Gardner Robinson

Okinawa attracts hordes of travelers to its sandy beaches and warm, clear water with divers and snorkelers often posting images of the majestic local sea turtles. The interior forest and rivers, however, are home to another Okinawa turtle also in need of protection—the small, reclusive, but equally beautiful, yamagame.

Okinawa’s yamagame (Geoemyda japonica Fan, 1931) are a small forest dwelling species of turtle found in the Ryukyu archipelago of southern Japan, namely on Okinawa Island, Kume Island, and Tokashiki Island. In an effort to protect this freshwater turtle species, the Japanese government designated them as a National Natural Monument in 1975.

In 2000, Tsutomu Otani launched the only field study permitted by Japan’s Ministry of the Environment. The study focuses on the capture-mark-recapture of turtles throughout the year in Yanbaru National Park, the wild northern region of Okinawa Island. Otani has identified hundreds of unique individuals at the research site and has gained invaluable knowledge about their habitat, behavior and ecology.

Yamagame, which translates to “mountain turtle” (officially called the Ryukyu black-breasted leaf turtle) are listed as endangered and are believed to be in decline due to continuous land development and poaching for the pet trade. The government has no ongoing conservation plan for the yamagame and without Otani’s study, there would be no way of monitoring the wild populations. Each passing year Otani finds fewer and fewer turtles. He’s reached retirement age and is in need of assistance to continue the study.

Aya Narukiyo and Dr. Zach Bell heard many stories about Otani and the yamagame and wanted to help. In 2020, they founded the Okinawa Kame Centre, a non-profit organization focused on protecting and conserving yamagame and their habitat on Okinawa Island. Since then the organization has expanded their conservation efforts to include two additional species, the yellow-margined box turtle and the yellow pond turtle.

What does the Okinawa Kame Centre primarily do?

Our association mainly focuses on the protection and conservation of the Ryukyu black-breasted leaf turtle. This is the only native species of freshwater turtle on Okinawa Island.
These turtles are true climbers and can be found high in the mountains of the northern region of Okinawa island called Yanbaru—a UNESCO World Heritage Site. This is likely how they received their local Japanese name リュキュヤマガメ (Ryukyu mountain turtle).

Adults are about the size and weight of a smartphone and can be found with bright red colored skin and attractive patterns on the shell. Little is known about their natural behaviors in the wild and thus there is still much to learn. Unfortunately the wild population appears to be decreasing, evidenced by less sightings during the field study.

What challenges are the turtles facing?

The major challenge for the turtles is their shrinking natural habitat. These turtles are geographically isolated to three small islands and thus land development for commercial use is a major concern. For example, farming in Yanbaru includes clearing trees and rerouting water ways, which not only damages the natural habitat but likely attracts more predators to the turtles. In recent years more crows, a turtle predator, have been seen in and around the turtle’s natural habitat.

With land development comes the construction of more roads. Roads cut through the turtle territories and dodging cars becomes yet another challenge for the turtles. Every year turtles are killed by cars on the road in Yanbaru, despite the warning signs like “Slow Down for the Turtles” or “Stop Roadkill.”

The beauty and rarity of these turtles has created yet another challenge for them. They are highly coveted by turtle collectors around the world and are unfortunately illegally smuggled from the islands and into the international exotic pet trade. Despite these known challenges, the government has yet to develop an effective conservation plan for wild turtle populations.
What are you doing to combat this?

To better understand these challenges and determine the best interventions, we joined Tsutomu Otani, a local herpetologist who maintains the only field study permitted by the Japanese government that is monitoring the turtles in the wild.

Although the field site is limited to a narrow trail, less than three kilometers long, we are able to gather vital information about the number of turtles in that region, their health, and the impact humans have on them and their habitat. We are currently looking for help to expand our study to more areas of Yanbaru by working with land developers and land owners.
We’ve realized during the research that many people are unaware of the turtle and its challenges. To raise awareness we provide educational materials on our website and social media about yamagame. We have a special interest in education targeting foreigners living in Okinawa, visitors, locals and people abroad who are interested in turtle conservation. To protect the turtles and their habitat we do not bring people to the survey sites, rather encourage people to see the beautiful creatures in one of the exhibits on island.

OKINAWA TURTLE CENTRE

The Okinawa Turtle Centre’s goal is to protect and conserve the Ryukyu black breasted leaf turtle on Okinawa Island. They accomplish this through field studies and education. You can support the cause by reporting freshwater turtle sightings via the form on their website or through monetary donations and “wish list” items that can be ordered on Amazon. OTC also recruits volunteers. Visit them online for more information and be sure to follow them on Instagram @Okinawakamecentre.

YAMAGAME EXHIBITS IN OKINAWA

Visitor’s in Okinawa can see fresh water turtles at the following places: