In findings published by the Zoological Society of London in the journal Royal Society Open Science, conservation scientists found “strong evidence” that the mammals are extinct in the country.
Scientists made the discovery following interview surveys in fishing communities across China. Data from previous years was also used to compare past dugong presence in the country.
Sometimes referred to as “sea cows,” due to their seagrass diet, dugong can be found in coastal waters in the Indian and western Pacific Ocean. The species is listed as vulnerable by the International Union for Conservation of Nature (IUCN.)
They have been protected in China since 1988 and have lived there for hundreds of years.
According to the study, scientists would “welcome any possible future evidence that dugongs might survive in China,” however the authors of the study said it provides “important evidence of the probable regional loss of a charismatic marine megafaunal species.”
Surveys found no evidence of dugong in Chinese waters. Before noting them as extinct, scientists considered the possibility that the species moved north along the coastline “in response to human activities or climate change.” They concluded, however, that this was unlikely as there is a lack of seagrass beds north of the dugongs’ usual habitat.
The study also notes that “no other dugong sightings or strandings have been reported,” from that area.
The authors of the study are also recommending changing the species’ status to critically endangered (possibly extinct).
Samuel Turvey professor at ZSL’s Institute of Zoology and co-author of the study told Newsweek that their extinction in China could lead to “a major negative impact on the health of seagrass systems.”
“However, the disappearance of dugongs from the northern South China Sea has been largely driven by the disappearance of the seagrass beds themselves - tragically, the entire ecosystem has been progressively destroyed through human activities,” he said.
Turvey said that dugong are a “keystone species,” meaning they can “help to shape the structure of their wider ecosystem.”
“Our study demonstrates the usefulness of using local ecological knowledge to understand the status of threatened biodiversity and to reconstruct extinction dynamics - and we encourage other conservation studies to engage with local communities to assess environmental requirements and threats to other rare species,” Turvey said. “Tragically, our findings also demonstrate the rapid disappearance of dugongs from Chinese marine ecosystems – highlighting the crucial importance of developing effective conservation measures before it is too late.”
The dugongs’ decline in China was mostly down to a loss of habitat. Turvey said this is through factors such as coastal development as well as water pollution.
“In particular, seagrass beds are very vulnerable to “eutrophication” - algal blooms resulting from human-caused increases of nutrients in the water (e.g. from sewage), that decreases the ability of light to penetrate through seawater and thus prevent seagrass photosynthesis.
