Chinese scientists have recently confirmed the presence of a dugong aka "sea cow" — one of the oldest marine mammals — in the coastal waters near Yongshu Reef in China's Nansha Islands since early July. The discovery marks the first verified sighting of the species in the Nansha Islands and central South China Sea in three decades and indicates a significant improvement in the region's ecological system.

This marine mammal was first spotted surfacing to breathe on July 8 by patrol personnel from Yongshu Reef's environmental protection department. Its activities in the same area were continuously monitored over the following month. On Aug 2 and 3, two observations at close range enabled the collection of video evidence.

Qin Geng and Li Songhai, researchers from the South China Sea Institute of Oceanology, Chinese Academy of Sciences, confirmed that the creature is a dugong based on relevant evidence, and that it is the first time the species has been found in this area. Their identification was further verified when a team of scientists witnessed dugong activity on the morning of Aug 11.

Weighing around 500 kilograms and measuring up to 3 meters in length, the dugong — a prototype for the mermaid in Chinese folklore — inhabits the warm coastal waters of the Indian and Pacific Oceans. This herbivorous mammal has a high dietary requirement for seagrass and plays a crucial role in maintaining the health of the ecosystem by promoting seagrass regeneration through its grazing behavior.

Although dugongs have a long life span of 70 years, they have a slow birth rate, making it difficult for populations to recover from disruptions. The species is under first-level State protection and is categorized as vulnerable by the International Union for Conservation of Nature.

Due to hunting, habitat loss, collisions with ships and other human interventions, the dugong was evaluated in 2022 as functionally extinct in China — defined as a species unable to reproduce or survive in natural habitats due to human activities — with the last confirmed sighting being a dead individual in Dongfang, Hainan province, in 2008.

"This finding provides crucial clues to the species' transoceanic migration patterns under the dual impact of climate change and human interventions," Qin said, adding that this dugong might have deliberately migrated to the area or been carried there by ocean currents.

Qin added that more evidence and observations are needed, as dugongs typically move in groups, yet this appears to be an individual.

Song Xingyu, a researcher at the institute, noted that traces of activity from China's first-level protected species — green sea turtles and hawksbill turtles — had also been observed near Yongshu Reef earlier this year.

"Green sea turtles rely on sandy beaches for nesting and reproduction, while the survival of hawksbill turtles is closely tied to the health of coral reefs. The presence of the dugong indicates the integrity of seagrass bed ecosystems," Song said.

"The successive discoveries of these three species in the waters around Yongshu Reef underscore the unique ecological value of the reef's island ecosystem," he added.

The 2024 South China Sea Region Marine Ecological Conservation and Restoration Bulletin reveals significant progress in recent years in the conservation and restoration of mangrove forests, coral reefs, coastlines and islands, as well as in controlling invasive smooth cordgrass. Last year, the total investment in marine ecological conservation and restoration of the region exceeded 5 billion yuan ($697 million).