August 24, 2022 report
Dugongs likely to be functionally extinct in China

A small team of researchers from China, the U.K. and Greece reports that dugongs are likely functionally extinct in China. In their paper published in the journal Royal Society Open Science, the group describes interviewing a large number of people living in fishing communities in areas formerly occupied by dugongs.
Dugongs are marine mammals that look like a cross between a seal and hippopotamus. They are of the order Sirenia, which includes manatees. They survive by eating seagrass. Over many years, dugongs of all kinds of have seen a dramatic drop in population as they have been hunted both for their meat and their oil. In this new effort, the researchers sought to find out if dugongs native to China have gone extinct.
The work involved conducting interviews with fishermen and other people living in fishing communities, asking whether they had seen a live dugong, and if so, when.
In speaking with 788 people, the researchers found that just 5% of them reported seeing a dugong, all of which were five or more years in the past—the mean sighting time was 23 years ago. And in looking at historical records of dugong catches, the researchers found they peaked during the 1960s and fell dramatically during the 1970s and onward. There have been no reports of anyone catching a dugong since 2008 and no reports of field observations since 2000.
The findings strongly indicate that dugongs have experienced a dramatic drop in numbers to the point that they are now functionally extinct in China. This designation is given to creatures that disappear from the fossil record and/or reports of sightings cease. The designation does not suggest that there are no more dugongs living in China, but that the population is no longer viable.
Prior research has suggested that the dugong population decline experienced in China was due to overhunting and loss of habitat, particularly seagrass. Seagrass beds in China have been in decline due to agricultural and industrial pollution, development of coastal areas and climate change. Dugongs remain in other countries, but most are also in decline.
More information: Mingli Lin et al, Functional extinction of dugongs in China, Royal Society Open Science (2022).
Journal information: Royal Society Open Science
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