Thousands of Chinese boats mass at sea, raising questions

"Something didn't look right to me because in nature very rarely do you see straight lines," said Wang, chief operating officer of ingeniSPACE, which analyses satellite imagery and ship signals data.

"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.