Nesting activity among sea turtles in Amami Oshima, an island in Kagoshima Prefecture, has continued to decline, raising concerns among researchers about population numbers.
While the island is known as a year-round destination for snorkeling and one of the best spots in the country to see sea turtles in their natural habitat, last year’s nesting figures were the second lowest since data collection began in 2012.
Scientists believe declining populations may be a key factor and have warned that a long-term analysis is needed to assess the situation.
According to the Amami Marine Life Research Association, which aggregated data from the Environment Ministry and five municipalities on the island, sea turtles landed 521 times between February and September last year, resulting in 289 recorded nesting attempts.
This was only slightly higher than 2023, when nesting attempts hit a record low of 260. By contrast, nesting peaked at 1,081 in 2012, meaning last year’s figure represented a roughly 75% decline. Since 2021, nesting attempts have remained below 400 annually.
Loggerhead turtles, which primarily feed on shellfish and crustaceans, have seen particularly sharp declines. In 2012, they nested 605 times, but by 2015 that number had plummeted to 150. Although there were occasional rebounds in some years, the downward trend has persisted, with just 47 recorded nesting attempts last year.
Katsuki Oki, the 53-year-old president of the association, pointed to unintentional bycatch in East China Sea fisheries as a possible contributor to the declining sea turtle population, as well as a reduction in food resources. However, he emphasized that no definitive causal link has been established as of yet.
“A nationwide, long-term monitoring effort is needed to fully understand the trend,” he stated.
Oki also stressed the importance of environmental conservation, noting that sea turtles are highly sensitive to light, which can disrupt their nesting behavior. He urged the public to avoid using fireworks or walking on beaches with LED flashlights during nesting season.
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