JINAN, June 15 (Xinhua) -- Ten meters below the ocean surface off Wuzhizhou Island of the south China island province of Hainan, a small robotic inspector glided silently among branching corals. Seen via its cameras were hawksbill turtles, parrotfish and a reefscape that, a decade ago, was nearly dead. The island's marine ranch once faced coral collapse. Since 2010, artificial reefs have helped restore this habit