Expert: conclusion Science

 Expert: conclusion Science

This conclusion is scientific and will not change, Dr. Wei Qiwei Wei, chief scientist and researcher of the Yangtze River Fisheries Research Institute of the Chinese Academy of Fishery Sciences, the corresponding author, told the Beijing News He said the news should have been released earlier, the dead are gone and there is nothing we can do. We should let the living live better, or do what we can to keep the living alive.

Beijing News recently, a research paper published online by the international academic journal Science of the total environment revealed that the extinction of the Yangtze River white sturgeon means the disappearance of another unique species in Chinas Yangtze River. However, the IUCN said on its official microblog yesterday that the final results have not yet been released and are expected to be released in June this year. According to the current preliminary results, the situation of sturgeon is not very optimistic.

No sturgeon has been found since 2003

The paper, pre proof, titled extinction of one of the worlds largest freshwater fish: lessons from protecting endangered animals, was published online on December 23, 2019.

Dr. Wei Qi Wei, chief scientist and researcher of the Yangtze River Fisheries Research Institute of the Chinese Academy of Fishery Sciences, said in his paper that it is estimated that the Yangtze River sturgeon, the king of Chinese freshwater fish, will be extinct in 2005-2010. The news should be announced earlier. Wei Wei told the Beijing News.

According to his explanation, if there is no natural reproduction and the natural life span of the species has passed, and no individual is found during this period, the species can be considered extinct. The lifespan of the Chinese sturgeon is generally about 30 years. The last discovery of natural propagation of the Chinese sturgeon was in the early 1990s. Since 2003, no sturgeon has been found, and no individual has survived in artificial culture. It can be inferred that it is extinct.

The World Conservation Union has carried out a comprehensive assessment

After the above papers were released by the media, they attracted wide attention. The topic of extinction of the sturgeon rushed to the hot microblog search, with a reading volume of nearly 500 million.

The World Conservation Union (IUCN) responded by saying on its official microblog that the final results of the ongoing comprehensive assessment of sturgeons in Asia and Europe have not yet been released. It is expected that the red list of threatened species will be updated during the World Conservation Conference in June this year, and the assessment results and corresponding level adjustments will be released in a positive manner.

At the end of the article, the group also said: according to the current preliminary results, the situation of the sturgeon is not very optimistic.

To this end, Wei Wei told reporters, the conclusion is scientific and will not change.

At present, the existing flagship species in the Yangtze River ecosystem include Chinese sturgeon, Yangtze sturgeon, Yangtze River finless porpoise, etc. However, their protection situation is also very serious, such as Chinese sturgeon, Yangtze River sturgeon, Yangtze River finless porpoise and other rare species are on the verge of extinction. The dead are gone, there is nothing to do. We should make the living better, or do what we can to keep the living alive. Wei Wei said.

Question 1

What is the survival status of the white sturgeon in recent decades?

In the past 35 years, no supplementary group of juvenile Acipenser sinensis has been found in the whole river section; in 1996, it was listed in the list of critically endangered species

The body of the white sturgeon is shuttle shaped, slightly flat at the front, thick at the middle and slightly flat at the back. Although it is called the white sturgeon, only its abdomen is white, and its head, back and tail fins are blue gray. It has a long and sharp kiss, so it is also called elephant nose fish by the ancients; the mouth is on the ventral side of the head, with only a row of tiny teeth in the mouth. The upper lobe of the developed caudal fin is larger than the lower lobe, which is called askew tail.

People often compare Chinese sturgeon to living fossil and king of Yangtze River fish. In fact, from the fossil record, Chinese sturgeon is older than Chinese sturgeon.

It is understood that the paddlefish and the paddlefish living in the Mississippi River are the only two remaining species of paddlefish. Their ancestors appeared on the earth as early as 100 million years ago (Cretaceous).

But unlike the species at the top of the ecological chain, such as the Chinese sturgeon, the baiji dolphin and the finless porpoise, the popularity of the Chinese sturgeon is relatively low. Until this extinction news, the silent species was put into public view.

In 1983 and 1987, the Environmental Protection Commission of the State Council issued the list of key protected wild animals, which listed the white sturgeon as a kind of rare and precious animals under key protection. In 1988, it was listed as a national first-class protected animal. In 1996, it was listed as a critically endangered species under the IUCN Red directory, and it was listed in Appendix II (CITES appendix) of IUCN (1996) crcites (1997) for protection.

Question 2

How was the last contact with the sturgeon?

In 2003, experts rescued a white sturgeon and tracked it. When the ship was tracking, it hit the reef, so far there was no trace of the white sturgeon

At about 2 p.m. on December 11, 2002, a white sturgeon was caught by fishermen fishing in the north of Xiaguan submerged island of the Yangtze River. After the news spread, Wei Wei and another expert arrived in Nanjing from Wuhan to carry out protection and rescue work on the spot. This is a 3.3-meter-long female paddlefish weighing about 130 kg. She is aged 15-20 and in middle age.

This is the first time that a live white sturgeon has been found since 1993. Unfortunately, after a months efforts, the white sturgeon was not treated successfully.

At 3:00 p.m. on January 27, 2003, the rescue group successfully rescued the white sturgeon, released the sound mark of the white sturgeon, and carried out a follow-up study by the Yangtze River Fisheries Research Institute.

According to the paper, at 21:58 on January 29, 2003, when the paddlefish continued to move downstream to reach the jiulongtan river section, due to the rapidity of the beach and the complexity of the channel, the tracking speedboat ran into a reef, and the propeller and tracking equipment of the speedboat were damaged, unable to continue tracking.

There are three possible reasons for the loss of signals analyzed by the working group of Chinese sturgeon: the distribution and behavior of Chinese sturgeon are less known by human beings; the riverbed is complex, forming many signal dead angles; the sonar generator is directly fixed on the body of Chinese sturgeon, which may be deposited in the rock crevices or submerged by sediment after falling off.

According to the article Chinese sturgeon protection and industrial development management published by Zhou Xiaohua, national aquatic wildlife protection branch in September 2019, in April 2006 and January 2007, when the scientific research department carried out sonar detection on the Pingshan Luzhou Mido river section, eight suspected signals of sturgeon were detected successively in the Baixi Nanxi River section.

But the body of the sturgeon, no longer appear.

Yangtze sturgeon

According to the public information, the Yangtze River paddlefish, also known as the Chinese spoon paddlefish and the Chinese swordfish, is the largest freshwater fish in China. It is 2-3 meters long and weighs 200-300 kg. The largest body length can reach 7.5 meters. Because its kiss minister looks like a trunk, also known as the elephant fish.

The ancient Chinese sturgeon is called tuna. In spring, they go back to the river to lay eggs. It is mainly produced in the main tributaries of the Yangtze River from Yibin to the Yangtze River Estuary, and also found in the Qiantang River and the lower reaches of the Yellow River. It is a rare and precious special product of China, and belongs to the first level of national wildlife protection. At present, the amount of resources has decreased significantly year by year, and is in danger. It is known as giant panda in water.

Wang Jun, reporter of Beijing News

Source: responsible editor of Beijing News: Wang Fengzhi, nt2541