A diver frees a fish entangled by fishing nets at an ocean ranch near Wuzhizhou island in Sanya, Hainan province, on Sunday. Artificial reefs, coral transplantation and planned breeding and harvesting of aquatic products have helped restore the ocean ecology over the last decade. (Photos: Xinhua)

A diver cleans a fishing net that entangled coral at the marine ranch of the Wuzhizhou Island scenic area in Sanya, South China's Hainan province, Jan 12, 2020. There are more than 120 coral, shellfish and algae species on the surface of the artificial reef at the marine ranch.

A diver checks underwater equipment at Wuzhizhou Island Scenic Area's marine ranch in Sanya, South China's Hainan province, on Jan 12, 2020.

A diver cleans a fishing net at Wuzhizhou Island Scenic Area's marine ranch in Sanya, South China's Hainan province, on Jan 12, 2020.

A diver checks underwater equipment at Wuzhizhou Island Scenic Area's marine ranch in Sanya, South China's Hainan province, on Jan 12, 2020.

A diver cleans the fishing net at Wuzhizhou Island Scenic Area's marine ranch in Sanya, South China's Hainan province, on Jan 12, 2020.