"Tanegashima Loggerhead Sea Turtle Survey 2021" Takes Place amid Covid Restrictions
-- Data Acquired on Homing Cycles for Nesting, etc., to Gain Understanding of Sea Turtle Ecology --

Tokyo, July 22, 2021 – Since 2015 MHI Group has supported the “Tanegashima Loggerhead Sea Turtle Survey,” a program overseen by Earthwatch Japan, a Tokyo-based incorporated nonprofit organization (NPO).(Note1) The program, conducted annually on Tanegashima, an island south of Kyushu, is targeted at protecting loggerhead sea turtles, currently under threat of extinction, and creating a healthy environment for nesting by clarifying adult female homing rates, size measurements, and egg-laying success rates.

Before the COVID-19 pandemic, every year several dozen volunteers, both MHI employees and members of the general public, participated in the survey. This year, participation was limited to only six individuals: research specialists and staff of Turtle Crew, a local NPO. The survey was carried out on eight nights in late June, in three areas in the northern sector of Tanegashima’s Nagahama Beach.(Note1) A total of 26 turtles were encountered, and 20 Nesting events were confirmed.

The results of this year’s survey indicated a further decline in the number of loggerhead sea turtles landing on Tanegashima to lay eggs. Also, measurements of the nesting females revealed a decline in the number of turtles under 80 centimeters long, which normally feed on plankton in the Pacific Ocean, and an increasing number of turtles of larger size, which generally feed on nutrient-rich shrimp and other seabed fauna on the continental shelf centered on the East China Sea. The cumulative number of turtles identified since 2015 reached 177, adding useful data relating to the loggerhead sea turtle’s ecology.

For the first time, drone technology was used in this year’s survey. In addition to giving the survey team an aerial understanding of conditions on the beach before the survey, the drone’s GPS function was used to identify nesting locations, thereby aiding coordination by the survey team working under nocturnal limitations. From next year’s survey, the team is considering expanding drone surveillance to include photography offshore, to permit visual identification of turtles on the ocean surface waiting to go ashore at night to nest.

Yoshimasa Matsuzawa, chairman of the Sea Turtle Association of Japan and head of the project’s research members, was pleased with this year’s results. “Blessed with favorable weather, we were able to achieve a productive survey despite the limited number of participants. Unfortunately, the number of nesting turtles continues to decrease, not just where we conducted the survey but at other locations in Japan as well, so we need to urgently investigate the causes for this. This year, surveys at some onshore locations were suspended because of the pandemic, so next year we hope to resume surveys, with help from volunteers, on the normal scale, to acquire meaningful data for clarifying the loggerhead sea turtle’s ecology.”

MHI Group looks forward to participating in the Tanegashima Loggerhead Sea Turtle Survey again starting next year as the Company continues to carry out activities to help protect the global environment and biodiversity, toward achieving a sustainable society.

• 1For further information on the survey program:
  • Supporting conservation survey for loggerhead turtles in danger of extinction
• 2Loggerhead sea turtles come ashore at night to lay their eggs. This year’s survey was conducted between 9 p.m. and 2 a.m. with the aims of confirming nesting events, attaching identification tags and measuring shell dimensions.

See also:

• Sea Turtle Association of Japan (in Japanese)
• EarthWatch Institute Japan (in Japanese)
• EarthWatch Institute