Report finds marine ecology of China's Huangyan Dao to be top tier

The quality of the marine environment around China's Huangyan Dao is classified as top tier, with both seawater quality and marine sediment meeting Class I standards, according to an assessment report released on Wednesday.

The report said that residual levels of heavy metals and petroleum hydrocarbons in fish samples were found to be below the evaluation criteria. Furthermore, the report emphasized the healthy state of the coral reef ecosystem, noting good conditions within coral communities and a rich diversity of coral species.

The report was compiled by specialized survey teams established jointly by the South China Institute of Environmental Science, National Marine Environmental Monitoring Center, and the Monitoring and Scientific Research Center under the Pearl River Basin and South China Sea Ecological Environment Supervision Administration.

The three units conducted a systematic field investigation from May to June 2024, covering aspects such as seawater quality, sediment quality, biomass, marine debris, coral communities, reef-dwelling fish species and other biological groups. They also collaborated with two key laboratories at Guangxi University and the South China Sea Institute of Oceanology of the Chinese Academy of Sciences to conduct a comprehensive evaluation of the ecological environment based on the two laboratories' years of previous surveys, research findings and satellite remote-sensing data. 

This comprehensive assessment also unveiled four significant discoveries. It confirmed for the first time that cyanide, a highly poisonous chemical that can be used for electroplating, manufacturing of paints, etc, was undetected in seawater, sediments and fish within and around Huangyan Dao. 

Additionally, the report assessed marine debris pollution levels, which were found to be relatively low compared to other offshore areas internationally. 

It documented and analyzed the status of reef-dwelling fish species and also conducted the first quantitative survey of the habitat density of giant clams, identifying key ecological groups, such as blue corals, fire corals and soft corals.