China News Service, Beijing, July 27 (Liu Huan) Recently, the World Conservation Union IUCN (hereinafter referred to as: IUCN) updated the species red list, and my country's endemic rare animal, the Yangtze river white sturgeon, was officially declared extinct.
Once the news was announced, it sparked heated debate.
Why did the "king of freshwater fish in China" written in folk songs go extinct after swimming through the Cretaceous period?
What should we do to prevent such incidents from happening again?
Source of adult white sturgeon: provided by respondents
How to judge extinction and extinction in the wild?
In this updated list, not only the white sturgeon was declared extinct, but also China's endemic Yangtze sturgeon was declared extinct in the wild.
Wei Qiwei, chief scientist and researcher of the Yangtze River Fisheries Research Institute of the Chinese Academy of Fishery Sciences, explained in an interview with Chinanews.com that extinction refers to species that cannot find living bodies in the wild, original habitats and artificial breeding conditions.
Extinction in the wild is a group of species that has no living organisms in the wild, only artificial and ex situ conservation.
In fact, the extinction of white sturgeon is not new news.
As early as 2010, Wei Qiwei and his team worked with foreign counterparts to make a model, observed data and recorded, and speculated that the white sturgeon was extinct.
In September 2019, IUCN organized an expert group assessment in Shanghai, and the assessment result was extinction.
In December, Wei Qiwei and his student Zhang Hui published a paper stating that the extinction time of the white sturgeon was 2005-2010.
In other words, if you push back from now, the white sturgeon had completely disappeared 12 years ago.
However, as early as the 1970s, white sturgeon and Chinese sturgeon were not uncommon in the Yangtze River, and they were mostly eaten after being caught.
According to the literature, the catch of white sturgeon was about 25 tons or 676 tails per year before 1976.
Source of Yangtze sturgeon juveniles: provided by respondents
Why is "Fish King" gone?
The turning point came in 1981.
Zhang Yulin, a professor at the Department of Sociology at Nanjing University, stated in his paper "The Yangtze River in the "Anthropocene" Era: Social Dynamics of Life Decline" that between 1981 and 2003, in addition to groups of juvenile sturgeons first discovered at the mouth of the Yangtze River, there were 210 sightings recorded. , of which there were only 3 after 1996.
Sturgeons are now considered "the most threatened taxa in the world".
Ren Wenwei, director of the Shanghai Regional Project of the Beijing Representative Office of the World Wide Fund for Nature (WWF), said that sturgeon has a high degree of overlap with human living areas, and is relatively more directly affected by its activities. "Sturgeon usually needs to migrate, and its The process is easily hindered and therefore more vulnerable to threats.”
When talking about the reasons for the extinction of white sturgeon, Wei Qiwei said: "The inability to reproduce is the main reason. They cannot go back to the spawning grounds in the upper reaches of the Yangtze River to spawn." He added that fishing, shipping, etc. also have an impact, "Sturgeon is relatively Gentle fish, slow swimmers, and relatively large individuals are prone to accidental catches and collisions."
The white sturgeon has been declared extinct, and now Wei Qiwei is most worried about the Chinese sturgeon.
Chinese sturgeon is larger in size and needs more aquatic food resources for survival.
They are river-sea migratory fish. They spawn in the lower reaches of the Jinsha River. After growing in the ocean for 14 years, they will go back to the Yangtze River after the breeding season.
Therefore, the Chinese sturgeon has higher requirements on the living environment and is more difficult to protect.
Although the artificial breeding of Chinese sturgeon has been successful in the 1970s.
However, in 2021, only 15 Chinese sturgeon breeding colonies were monitored in the spawning ground under Gezhouba, and the only 15 remaining have not reproduced naturally for five consecutive years.
Some professionals judged that the prospect of the natural population of Chinese sturgeon is not optimistic.
Compared with the above two kinds of sturgeon, the Yangtze River sturgeon is smaller and distributed in the upper and middle reaches of the Yangtze River and its main tributaries and large lakes, and artificial breeding has also been successful.
However, due to problems such as inability to reproduce and water pollution, the Yangtze River sturgeon has rapidly become an endangered species from an economic fish.
After 2010, the wild Yangtze sturgeon has basically disappeared, and there are only about 20 wild individuals in artificial conservation by 2018.
Not only sturgeon, but also freshwater species in the Yangtze River basin, such as Sichuan-Shaanxi Zheluo salmon and bluestone crawfish, are also at risk of being endangered.
The Yangtze River, which once had 48% of the country's freshwater fish, has been deteriorating in recent years, and fish populations have been severely affected. The Yangtze River's biological integrity index has now reached the "fish-free" level.
According to the "Yangtze River Vitality Report 2020" written by WWF and more than 30 authoritative experts in the industry from eight scientific research institutes in two years, since the 1980s, the number of fish species in the main stream of the Yangtze River has decreased by 122, a decrease of 1/2. 3. Among them, there are 48 unique fish species, a decrease of 29%.
Wei Qiwei said: "Fish can speak on behalf of the environment. The number of fish is small and the distribution range is narrow, indicating that the environment is not good. Therefore, fish understands water best."
Chinese sturgeon source: Endangered Fish Conservation Group (CEF) official website
The last time I saw a sturgeon
On January 24, 2003, the white sturgeon was last seen in Yibin, Sichuan.
This white sturgeon was accidentally caught by fisherman Liu Longhua in a puddle of rocks and water at the mouth of the Fuxi River in the Yangtze River.
The white sturgeon that swam into the fishing net was frightened and rammed around.
Mu Tianrong, then director of Yibin Fisheries and Fisheries Bureau, rushed to the scene immediately after hearing about it.
He saw that the white sturgeon, which was more than three meters long, was like a cow. It was wrapped beside the fishing boat. There was a 20-centimeter-long wound on its head and a scratch on its tail fin.
Mu Tianrong reported to the Yangtze River Fisheries Research Institute and assisted Wei Qiwei and other experts from Wuhan to carry out rescue work. After a series of medical treatment, the white sturgeon recovered on the fourth day, and Wei Qiwei put it into the river by himself. .
On July 22, 2022, after hearing the news of the extinction of the white sturgeon, Mu Tianrong, who had retired, was choked up and speechless.
Wei Qiwei, who has rescued dozens of white sturgeon, said: "It is true that sturgeon is the most threatened group in the world, but the extinction of white sturgeon is still something that should not happen... This is not an accident, but a profound lesson. Other Yangtze aquatic organisms must not repeat the same mistakes... The Yangtze and Chinese sturgeons should not only have a future of extinction."
Wei Qiwei is more optimistic about the future breeding numbers of sturgeons, "We are still doing things, and we release them every year. When the population is restored, there is hope for the natural breeding of sturgeons." He said, "The Yangtze River "Great protection" has become a consensus in China, and relevant policies have been implemented one after another.
Since 1983, my country has banned commercial fishing. At the same time, in order to solve the problem of Chinese sturgeon being unable to reproduce, the Chinese Sturgeon Research Institute affiliated to the Gezhouba Group has implemented artificial breeding and release since that year.
In 1989, the Yangtze River white sturgeon and Chinese sturgeon were listed as national first-class key protected wild animals.
In 2002, the lower reaches of the Yangtze River began a trial period of a three-month spring fishing ban.
On January 1, 2021, the key waters of the Yangtze River Basin officially entered a ten-year fishing ban.
In the same year, laws and regulations such as the Yangtze River Protection Law and the Yangtze River Aquatic Life Protection Management Regulations were promulgated one after another.
After the sturgeon's survival attracted attention, conservation measures such as artificial population storage, proliferation and release, prohibition of fishing, and establishment of nature reserves in the Yangtze River Basin were jointly carried out to prevent Chinese sturgeon from following the footsteps of white sturgeon.
The fishing ban policy has been effective since its implementation. The relevant preliminary monitoring results released by the "Yangtze River Ecological Protection and Fishery Development Forum" at the 5th China Modern Fishery and Fishery Science and Technology Expo in November 2021 show that the common fish resources in the Yangtze River have a tendency to recover , the remaining small threatened fish populations in the ecological environment of the Yangtze River are showing signs of recovery.
For the protection of endangered species, WWF's "Rescue Restoration Plan - Reversing the Global Loss of Freshwater Biodiversity" proposes six urgent countermeasures, including:
1. Accelerate the recovery of environmental flow;
2. Improve water quality;
3. Protect and restore critical habitats;
4. Rationally manage the fishing utilization and sediment extraction of freshwater species;
5. Prevent and control the invasion of alien species;
6. Maintain the connectivity of rivers and lakes.
As a former "sturgeon rescuer", Mu Tianrong couldn't accept the news of the extinction, saying: "This reminds us that if the ecology is not well protected, there will be big problems."
A rescue more than ten years ago was very unforgettable to him. Mu Tianrong still remembers the white sturgeon with black plum blossom spots on its back. After a distance, he swam back, and then swam into the depths of the river.
Wei Qiwei installed an ultrasonic tracker on the side of the white sturgeon's waist to follow its footprints.
However, a few days later, the tracking ship unfortunately hit the rocks, and after the repair, no signal from the white sturgeon was received.
(Finish)