The Transport Ministry will this year tighten the physical checkup criteria for older marine pilots to ensure they are physically fit to guide large vessels through busy ports and bays, sources close to the ministry said July 8.

At the same time, the ministry will ease the requirements on examinations for a pilot's license, they said. The ministry contends the new health criteria are not intended to weed out older pilots and says the measure will be studied through the eyes of medical practitioners and experts. At present, pilots who are deemed healthy enough can work until they reach 77.

Pilot error is believed to have been the cause of the recent large oil spill in Tokyo Bay from the Panamanian-registered supertanker Diamond Grace, which hit a well-marked shoal. The pilot was Masaharu Ushio, age 57.

Like other parts of the world, foreign vessels must take on pilots locally when plying Japan's busy waterways if the ships are in unfamiliar territory or are not authorized to navigate independently. Pilots need not only good eyesight but also a certain level of physical strength. Often they have to board or leave a vessel that is under way in rough seas, the sources said.

Current physical checkup criteria call for pilots to have eyesight better than 0.8, but there is no standard to measure gripping strength. The new criteria will fix a minimum grip strength level and pilots who are unable to meet the requirements will fail the tests, according to the sources.

According to the ministry, there were about 760 pilots nationwide of the end of March, and their average age stood at 63. The oldest was 76.