你應該看英文的維基百科。英文的維基百科說的跟ChatGPT一致。

https://en.wikipedia.org/wiki/East_China_Sea

“Most of the East China Sea is shallow, with almost three-fourths of it being less than 200 metres (660 ft) deep, its average depth being 350 metres (1,150 ft), while the maximum depth, reached in the Okinawa Trough, is 2,716 metres (8,911 ft).^[2] ”