Sea Turtles
Yakushima Island Sea Turtles
Japan is one of the world's leading loggerhead turtle spawning grounds after the southeast coast of the United States and Oman, and the only such spawning ground in the North Pacific. There are three species of sea turtles that spawn in Japan. The main species spawning on Yakushima Island are the loggerhead and green sea turtles. Between 30 and 40% of all loggerhead sea turtles coming ashore in Japan do so on Nagata Beach on the northwestern part of Yakushima Island, making it the largest spawning area for loggerhead sea turtles in the Northern Pacific.
Nagata Beach is therefore a critical area for the protection of loggerhead sea turtles. In 2002 it was designated as part of the Kirishimayaku National Park (Yakushima National Park in 2012) and registered as wetlands under the Ramsar Convention in 2005. The Yakushima Ranger Office is proceeding with discussions with local stakeholders with the aim of protecting sea turtles throughout Yakushima, including Nagata Beach, preserving their spawning and hatching environments, and ensuring their proper use.
Sea Turtle Ecology
Sea turtle is a general term for animals belonging to the families Cheloniidae and Dermochelyidae within the order of reptiles known as Testudines. There are currently seven known species of sea turtle worldwide. Loggerhead sea turtles and green sea turtles are the two main species of sea turtles coming ashore on Yakushima Island. Most of these are loggerhead sea turtles. Sea turtles live most of their lives in the ocean and only come ashore on sandy beaches to spawn. The baby turtles hatched in Japan migrate throughout the Pacific, and finally live in the coastal waters. It is said that it takes about thirty years for the baby turtles to become parents.
Concerns
When the egg-laying season starts in late April, sea turtles come ashore on the beach at night. When they find a suitable location they dig a hole and spawn. However, the turtles are extremely sensitive to light and signs of humans, and if people walk around the beach at night and use flashlights, they will not come ashore or return to the ocean without spawning. In addition, baby turtles, which begin to hatch in early July, may be unable to break out of the sand, and die, if people walk round the beach and pack the sand down. There are also concerns that street lights and the lights of cars can impact their sense of direction since they move towards light.
Endangered Sea Turtles
Loggerhead sea turtles and green sea turtles are said to face the same risk of extinction as blue whales and chimpanzees. In Japan as well, the Ministry of the Environment has created a Red List, and the Fisheries Agency a databook, on rare wild life in Japan, and sea turtles appear as endangered species in both.
Classification of threatened Species by the International Union for Conservation of Nature (IUCN)
| Classification | Risk of extinction | Primary animals | Sea turtle |
|---|---|---|---|
Endangered species Category IA |
Species facing extremely high risk of extinction in the wild in the near future. |
Gorilla gorilla Sumatran rhinoceros |
Hawksbill sea turtle Leatherback sea turtle |
Endangered species Category IB |
Species facing high risk of extinction in the wild in the near future, however risk not as high as IA (CR). |
Blue whale Chimpanzee |
Loggerhead sea turtle Green sea turtle |
Endangered species Category II |
Species facing a growing risk of extinction. Species predicted to definitely move to Category I (CR and EN) in the near future. |
Sperm whale Polar bear |
Olive Ridley sea turtle |
