Recently, when fishermen in Taiwan, China were fishing with fixed nets in the waters of Yilan, a strange large cargo came to the net, and when they untied the net, they realized that it was a dugong.

△ Dugongs caught in Taiwan

The dugong is likely to be the prototype of the legendary mermaid, and it is believed that the last recorded dugong sighting in Taiwan dates back to 88 years, so this is the first time in 0 years that the dugong has been in Taiwan.

中國大陸最近一次儒艮目擊事件則是在2008年，一頭已死的儒艮擱淺在海南省文昌市附近（下圖），之後就沒有官方的相關記錄了，所以中國在2022年宣佈儒艮功能性滅絕——這意味著即便中國還存在儒艮，那也不可持續的，會在未來走向滅絕。

Many people wonder if the reappearance of dugongs in Taiwan means that this unique animal, which is functionally extinct in China, has won the "resurrection race".

The simple answer is no! Even in the coming decades, it will be difficult for dugongs to win this "repechage match"!

Dugongs are the only surviving species in the family Dugongidae of the order Manatee, and they have a close relative who has just become extinct, the famous oneManatee(another species of the dugong family), this animal took only 20 years from its discovery by Westerners to its extinction, and is known as the "most miserable" animal.

Manatees are the only fully aquatic herbivorous mammals on Earth, with only two families in the order Manatee and Dugongs, and a total of only 4 species in existence – West Indian manatees, African manatees, Amazonian manatees and dugongs.

Among them, only the dugong is the most widely distributed and is the only manatee living in China.

△ Distribution of dugongs

儒艮生活在印度洋和太平洋沿岸的很多地方，現存大約有10萬頭，不過目前只有兩個地區的儒艮種群還算健康，分別是沙烏地阿拉伯和澳大利亞，這兩個國家幾乎擁有了所有野生儒艮。

Elsewhere, dugong populations are either on the verge of extinction or in declining numbers.

Although official sightings of the Chinese dugong stopped at 2008 years, it has also been declared functionally extinct.

But even so, it is normal to find dugongs in China, but many of them are specious sightings by fishermen, unlike the evidence that Taiwan has been caught this time.

Because dugongs are herbivores and grasses have limited calories, they migrate hundreds or even thousands of kilometers to feed.

Both the Ryukyu Islands and the Philippines now have wild dugongs, and there is a high probability that dugongs in both regions will enter the coast of Taiwan to feed, and then it is normal to accidentally be caught in a net.

In addition, in the dugong stranding incident in Hainan, China in 2008 (that is, the one mentioned above), experts determined that the dugong was a dugong group from the Philippines, which just foraged for food and migrated, and then may have been left alone or something, and finally died in a foreign land.

△ Flowers of seaweed Cymodocea nodosa

Why is it still so difficult to resurrect dugongs in China?

The food source of the whole manatee order including dugongs isseaweed, many people don't know about seagrass,This is the real grass, they are the only flowering plants in the ocean, the group of angiosperms that enter the ocean from the land。

After the higher angiosperms adapted to the seawater environment, the primitive plants in the sea naturally could not compete with them, so seagrass has been a huge success in the ocean, and the entire shallow sea in the world except Antarctica is basically occupied by seagrass, not those native marine plants.

但是可能由於海水環境無法有效隔離花粉的傳播，所以海草並沒有多樣化，全世界大約只有72種海草——它們彼此關係密切，而每個地區的海洋草甸中更是只包含一到兩種海草物種。

△ These are two species of seagrass that grow in the Hepu Dugong Reserve in Guangxi

The single species composition makes seagrasses very fragile and can easily die in one fell swoop, as is currently the case with seagrasses around the world, which are severely degraded due to environmental changes.

The degradation of seagrasses is one of the main reasons why manatees, including dugongs, are endangered.

Therefore, whether dugongs can be "resurrected" in China, the first thing to see is whether the seagrass recovers, but it turns out that as of 2022, when China declared dugong functionally extinct,Only a sparse 7.0 hectare of seagrass meadows remain in the Dugong Reserve in Hepu, Guangxi, and there is not even enough seagrass left to support a single dugong。

If you think about it, this is true in protected areas, and the situation in non-protected areas is probably only worse.

Seagrass degradation is the first reason why dugongs are unlikely to be "revived" in China at present.

△ 儒艮©Julien Willem

The second reason is:The number of dugong populations in the surrounding areas of China is also not optimistic, and wild dugongs are on the verge of extinction in the Ryukyu Islands, the Philippines, Japan, Malaysia, Sumatra, etc.

If an animal becomes extinct in one place, it must be allowed to migrate from other places if it is to recover naturally, but if the populations in other places are not optimistic themselves, the likelihood of migration is low.

thirdDugongs are an animal that has a great influence on generations of generations, and their living areas are very fixed and almost do not migrate to other places, so even if the dugong population around China is healthy, the probability of wild dugongs migrating to China again is extremely low.

A study in 1 [0] found that dugongs in different regions not only do not migrate, but there is even little genetic exchange between their populations, and the study divided the world's dugongs into five populations, and these five populations are fighting separately and basically do not interfere with each other.

There are two populations in China, one in the Chinese region, which forms a community with dugongs from Malaysia and Sumatra, and the other in the east coast of Taiwan, which forms a community with dugongs from Japan and the Philippines.

Dugongs in the same community will have more genetic exchange, but the area where they live in different families is very fixed, and they will hardly run around.This has a lot to do with the fact that each dugong learns about their environment and survival from their mother, and it is difficult for them to adapt to their environment outside of their native habitat.

The foraging migration of dugongs usually occurs in small groups, and its appearance alone usually means that it may be alone, soThe situation of this dugong fished and landed in Taiwan may not be optimistic, and if it is left alone, then it may not be able to live independently。

On the other hand, it is very difficult for dugongs to recover from functional extinction on their own!

Dugongs are very reproductive, they only live 26 to 0 years, but their generation intervals are 0-0 years, and they only give birth to one young per litter and have a lactation period of up to three years, which means that it is difficult for them to recover their populations.

In factFor a still existing animal, the dugong, a simple and effective way to recover from the extinction in one area is to reintroduce it directly from another area.

For dugongs, however, China may be far from ready for them at the moment, and they are not the kind of animals that are declared functionally extinct today and can be reintroduced tomorrow.