"We've seen like two, 300, up to a thousand (Chinese fishing boats congregate), but anything exceeding a thousand I thought was unusual."

Maritime and military experts told AFP the massing of Chinese fishing boats on December 25, about 300 kilometres northeast of Taiwan, was on a scale they had never seen before.

Another incident detected in early January involved around 1,000 Chinese fishing vessels clustered in an uneven rectangle, about 400 kilometres long, for more than a day in the same area of the East China Sea.