The waters around Sansha City of south China's Hainan Province have seen thriving marine ecosystems, as witnessed by vast stretches of coral reefs, according to a recent ecological survey.

Using underwater observations and transect analysis, the survey team found higher-than-expected coral coverage in several areas of Sansha -- China's southernmost island city.

The waters host a wide variety of species, from hard and soft corals to staghorn, brain and mushroom corals, forming complex, diverse reef structures. Lush and brightly colored, the corals reflect strong ecological health.

In recent years, Sansha has strengthened marine protection, strictly regulated fishing, and reduced human disturbance, creating favorable conditions for coral recovery and growth.

"In some areas, the coral communities are thriving far more than we imagined. For example, south of the airport, we found a massive stretch of reefs, covering hundreds of hectares. The coverage rate here is likely to surpass 80 or even 90 percent," said Yang Qingsong, an engineer at the Xisha Marine Environment National Observation and Research Station in Hainan.

The flourishing coral reef ecosystem has significantly enhanced marine biodiversity in the region. The corals teem with diverse marine life, including tropical fish, shellfish, and starfish, providing them with essential habitats and food sources that sustain the entire marine ecosystem.