A loggerhead turtle captured off Mexico in 2005 and released with a tag was confirmed to have come ashore on Yakushima Island earlier this month, officials at the nonprofit organization Yakushima Umigame-Kan said Monday.
It is the first time that a sea turtle has been confirmed to cross the Pacific Ocean from Mexico to Japan, according to the museum on the island in Kagoshima Prefecture.
The museum's director, Kazuyoshi Omuta, said that a volunteer with the museum spotted the turtle with a metal tag bearing the letters NOAA, the acronym of the U.S. National Oceanic and Atmospheric Administration, on the island's northwestern shore on July 3.
After contacting the U.S. agency, the museum found out from the tag's serial number that the turtle had been captured off the coast of Baja California Sur state in western Mexico in September 2005.
The turtle did not lay eggs in Japan apparently due to injuries to its flippers, according to the officials.
Researchers believe that loggerhead turtles hatched in Japan travel to waters off Mexico on the Kuroshio current before returning to breed in the same places where they were born. They do not know how long the process takes, according to Takashi Ishihara, a senior researcher at the nonprofit Sea Turtle Association of Japan.
The latest discovery "showed for the first time that sea turtles are sexually mature in about 6 to 7 years," Ishihara said. "This is valuable data for analyzing the ecology of sea turtles."