Sea Turtle Nesting
Two species of sea turtle, the loggerhead and the green turtle, come ashore on Yakushima. Japan is the only place in the North Pacific where loggerheads, the more numerous of the two, lay their eggs, and Yakushima beaches make up their largest nesting site.
Why Sea Turtles Like Yakushima
Young loggerheads hatch on the beaches of Yakushima and then migrate on the Kuroshio Current that flows past Yakushima to the northeast in the Pacific. The coast of Baja California in Mexico has abundant food, and many loggerheads journey there, eventually returning to Yakushima to lay eggs. All female sea turtles return to their place of birth to mate and nest, whereas male loggerheads generally do not.
The females lay their eggs on the sandy beaches of Yakushima during the nesting season between May and July. They come ashore at night so as to evade predators, dig a hole in the sand, lay their eggs, and then take 30 minutes or more to cover the holes with sand. Each female lays about 100 to 150 eggs at a time, laying two to six clutches a season. The eggs hatch after 45 to 70 days, and the black hatchlings, around five centimeters long, emerge from the sand after three to seven days and head for the sea.
Sea Turtle Protection Activities
Sea turtles have been endangered by human activities. Turtles were captured in great numbers for ornaments made with their shells until the 1950s or 1960s. Turtle eggs were also sold and eaten in Japan, as they had high nutritional content and were considered good for longevity and safe pregnancies. From the 1970s onward, indiscriminate fishing and environmental degradation further threatened sea turtle habitats.
The former town of Kamiyaku, comprising the northern half of Yakushima, banned the capture of sea turtles and their eggs in 1973 to protect them from extinction. Kagoshima Prefecture then established regulations in 1988 banning the illegal harvesting of sea turtles and their eggs in all coastal areas. In November 2005, Nagata Beach, a collective name for three beaches in Nagata, was registered under the Ramsar Convention on Wetlands, which recognized Nagata as having the most loggerhead turtle nesting sites in the North Pacific and as an important area for the turtles’ survival.
Yakushima Umigame-Kan, a nonprofit center dedicated to the ecological study and protection of sea turtles on Yakushima, plays a key role in monitoring and researching sea turtle ecology, cleaning up beaches, patrolling nesting, and training volunteers. Research groups and volunteers collect and monitor the number of turtles coming ashore and the number of eggs laid. Researchers tag sea turtles to track their migratory route by satellite.
Where to Go
Turtles nest at five main areas: Nagata’s Maehama and Inakahama Beaches, Isso Beach, Kurio Beach, and Nakamahama Beach. The beaches at Nagata are the most popular with visitors for their high likelihood of observing nesting activity.
Nagata Inakahama Beach
Stretching 1,000 meters, this beach in northwestern Yakushima is the longest sand beach on the island. Yakushima is the landing point for 40 to 50 percent of the loggerheads that come ashore in Japan, and 90 percent of them land at the Nagata beaches. The chances of seeing a sea turtle are highest from mid-May to June. Visitors must join the Sea Turtle Nesting Observation Tour (Umigame Kansatsukai) offered by the Nagata Sea Turtle Liaison Council to see the turtles, and advance reservations are required.
Yakushima Umigame-Kan
Umigame-Kan offers Sea Turtle Nesting Observation Tours at Maehama Beach. The tours start with an orientation on basic rules of observation and the biology of sea turtles. Participants next watch a video subtitled in English, then are guided to the nesting site. The number of participants is capped at 50 per day, and advance reservations are required. A museum displaying specimens, photographs, and panels detailing the life cycle of the turtles (including some in English) is open year-round (excluding Tuesdays, Wednesdays from October to March, and the year-end/New Year holidays). Entry is \300 for adults.
Kurio Beach
The second largest nesting area for loggerhead turtles after Nagata is this beach in southwestern Yakushima. Observation tours are not offered at Kurio; however, the sea turtle rangers who monitor activity on the beach will explain points of caution to observers.
