A marine survey ship that cut short its mission a day early on Sunday after being harassed by a Japanese Coast Guard aircraft was in a part of Taiwan’s exclusive economic zone that overlaps with Japan’s, an official said on Monday.
According to Japanese media reports, the survey ship from National Taiwan Ocean University (NTOU) was spotted operating in Japan’s 200 nautical mile (370km) economic zone near Hateruma Island in Okinawa Prefecture.
Hateruma Island is about 120 nautical miles directly east of Yilan County and about 260 nautical miles southwest of Okinawa Island.
The Maritime Safety Agency of Japan sent aircraft to ask the survey vessel to depart the area as soon as possible, the reports said.
Commenting on the reports, Su Qi-cheng (蘇啟誠), deputy secretary-general of the Association of East Asian Relations under the Ministry of Foreign Affairs, said the survey ship was operating in an area where the two countries have overlapping exclusive economic zone claims.
Taiwan and Japan are still negotiating the issue, Su said.
Gong Gwo-ching (龔國慶), a professor with the university’s Institute of Marine Environmental Chemistry and Ecology who headed the mission, said the ship left Keelung on Friday to survey the impact of Typhoon Saola on marine biological and ecological systems in the northwestern Pacific Ocean off Taiwan’s eastern coast.
Gong’s team was scheduled to conduct surveys at nine locations, but when the team reached the final stop some 60 nautical miles off Hateruma Island, a Japanese Coast Guard aircraft interfered with its operations.
“We originally planned to stay in the area for 10 hours to complete our survey, but decided to cut short our work and start back after Japan’s intervention,” said Gong, whose team returned to Keelung on Sunday evening, a day early.
It is not uncommon for the university’s survey ships to be interfered with by Japanese helicopters or patrol vessels during their survey missions, Gong said.
The survey ships are most likely to be harassed by Japan’s Coast Guard ships or aircraft when passing through waters surrounding the disputed Diaoyutai Islands (釣魚台), known as the Senkuku Islands in Japan, in the East China Sea.
Some team members complained that if Japan were to truly define waters within 200 nautical miles off its small islets as its exclusive economic zone, none of Taiwan’s ships could leave the country’s harbors.
A team member said Japan has become especially sensitive toward Taiwanese ships moving close to its small islands west or southwest of Okinawa probably because the Diaoyutai dispute has re-emerged as a hot topic in recent months.
The Diaoyutais are a group of uninhabited islands located some 100 nautical miles northeast of Taiwan and are also claimed by China and Japan.