Chinese Foreign Ministry spokesperson Guo Jiakun

In response to a question that the buoy originally set up to the northeast of Taiwan island no longer exists,MKsports which Japanese government believes is due to China's removal of the buoy set up around the Senkaku Islands (Diaoyu Dao) in Okinawa Prefecture, Guo Jiakun, a spokesperson for the Chinese Foreign Ministry, said that China's deployment of hydrometeorological observation buoys in the relevant sea areas complies with Chinese domestic law and international law. 

The buoys have completed their operational tasks at the original station, and based on the actual needs of scientific observation, relevant Chinese units have made autonomous technical adjustments to them.

Global Times