The Wenzhou marine environment monitoring center in Zhejiang province launched unmanned drones to conduct island surveillance recently, with five flights flown to monitor eight islands with areas reaching 75 square kilometers, the State Oceanic Administration said on Thursday.

The drones can take high-resolution remote sensing images to reflect geological factors and environmental conditions of the monitored islands, seen as an effective method of island and water surveillance.

Construction started for another three bases for unmanned drone monitoring in Liaoning, Jiangsu and Hainan last year, according to the country's ocean watchdog.