BEIJING, July 8 (Xinhua) -- The Philippine military vessel that has been illegally grounded at the lagoon slope of Ren'ai Jiao since 1999 has gravely damaged the diversity, stability and sustainability of the coral reef ecosystem in the area, said a report released Monday.

A Survey Report on the Damage to Coral Reef Ecosystem by Illegally Grounded Military Vessel at Ren'ai Jiao is based on a scientific survey conducted on the coral reef ecosystem at Ren'ai Jiao and its adjacent sea areas in April this year by the South China Sea Ecological Center and the South China Sea Development Research Institute of China's Ministry of Natural Resources together with other institutes.

The survey found that the grounding process has inflicted fatal damage on the coral reef ecosystem, and its prolonged grounding state has greatly inhibited the growth and recovery of corals in the surrounding area, said the report.

Heavy metal precipitation caused by corrosion of the vessel, coupled with discharge of domestic wastes and sewage by onboard personnel, has inflicted lasting harm on the corals' health, according to the report.

The health of the coral reef ecosystem has also been severely compromised by fishing wastes discarded by onboard personnel and Philippine fishing boats, said the report.

The survey was conducted through satellite remote sensing and field investigation, according to the report.

High resolution satellite remote sensing images shot from 2011 to 2024 were used to inverse the reef platform substrate types, and to calculate the shallow reef platform area and various substrate types within a depth of 20 meters, the report said.

The field survey was carried out at 18 survey stations along the reef platform margins, involving assessment of 75 parameters across four categories, namely coral communities, reef organisms, habitats and human activities, said the report.

China maintains indisputable sovereignty over Nansha Qundao (the Nansha Islands) and the adjacent waters, including Ren'ai Jiao, said the report.

A Philippine military vessel was illegally grounded on the lagoon slope of Ren'ai Jiao in 1999. The Chinese government promptly lodged formal protests and demanded the immediate removal of the vessel. The Philippine side has repeatedly promised to remove the vessel, yet as of today, the promise remains unfulfilled.

Over the past 25 years, the personnel onboard the military vessel have received supplies regularly, burned garbage, discarded waste and sewage, carried out fishing activities frequently and constantly fortified the vessel, according to the report.

Since 2017, the Philippine side has been building temporary facilities on the vessel, which cover about 90 percent of the deck. As of now, the hull has severely deteriorated, with extensive rust damage visible, said the report.

The report detailed the destructive impacts of the illegally grounded military vessel on the coral reef ecosystem.

From 2011 to 2024, it has been calculated that the aggregate coverage of reef-building corals at Ren'ai Jiao reef platform declined approximately 38.2 percent. The decline rate in the reef platform surrounding the vessel within a radius of 400 meters reached around 87.3 percent, said the report.

In addition, massive fragments of coral reef and dead corals were found around the vessel, showed the report.

The survey found that the community structure of benthic invertebrates at Ren'ai Jiao was imbalanced, especially in the area around the illegally grounded military vessel. The concentrations of heavy metals, dissolved inorganic phosphorus, and oils were significantly higher than historical records.

Amidst large-scale coral bleaching due to rising sea surface temperatures, attacks of strong tropical cyclones, outbreaks of coral predators and human activities, all pose significant threats to coral reef ecosystems.

However, since the vessel was illegally grounded at Ren'ai Jiao, there has been no evidence of large-scale coral bleaching or outbreaks of coral predators in the area, neither have there been tropical cyclones severe enough to devastate coral reef, according to the report.

Thus, in the Ren'ai Jiao area, the report concluded, the damage and degradation of the coral reef ecosystem was mainly caused by the illegally grounded military vessel and associated human activities.

The report said the Philippines should promptly remove the vessel, thereby eliminating the source of pollution, and preventing further sustained and cumulative damage to the coral reef ecosystem at Ren'ai Jiao.