On the evening of July 21, the International Union for Conservation of Nature and Natural Resources (IUCN) released an updated report on the Red List of Global Endangered Species, declaring the extinction of the white sturgeon and the extinction of the Yangtze River sturgeon in the wild. In the rare fish-sturgeon special stamp issued in 1994, a total of four species of sturgeon appeared, including the white sturgeon and the dasturtine sturgeon.
The results of the global sturgeon reassessment released this time show that all 26 species of sturgeon in the world are at risk of extinction. Carefully calculated estimates have shown that sturgeon have declined more rapidly over the past three generations than previously anticipated. On the IUCN Red List of Species, there are 17 species of sturgeon that are critically endangered, 3 species that are endangered and 5 species that are vulnerable.
In the last red catalogue released, there are still 27 species of sturgeon worldwide, of which 85% (23 species) are endangered and 63% (17 species) are ranked the highest in the IUCN red list and are classified as "critically endangered".
Globally, the report notes that major threats to sturgeon include illegal fishing from the illegal trade in wild caviar and fish meat, unsustainable sand and gravel mining destroying their spawning grounds, and habitat loss.
1, white sturgeon: known as the "king of freshwater fish"
"A thousand pounds of wax." This fisherman's proverb refers to the Chinese sturgeon and the latter to the white sturgeon.
One of the 1994 rare fish-sturgeon stamps was the white sturgeon, and the other three were the Chinese sturgeon, the Dashi sturgeon and the sturgeon.
The story of the white sturgeon is even more poignant. The white sturgeon is known as the "tiger in the water" and "the king of Freshwater Fish in China", mainly distributed in the Yangtze River system. Like the Chinese sturgeon, it has existed for 150 million years and is one of the very few ancient fishes that survived from the Cretaceous Cretaceous of the Mesozoic Era. The last time live white sturgeon was seen in the wild was in 2003, in the Nanxi River section of Yibin, Sichuan. After the expert rescued a white sturgeon, it was equipped with an ultrasonic tracker and released, but because of the rapid water, in the middle of the night, the tracking boat accidentally hit the reef, resulting in the loss of the white sturgeon. Since then, after many searches and thousands of kilometers of searching, the whereabouts of the white sturgeon have never been found.
For 19 years, no one has ever seen this ancient creature in reality.
2. Yangtze River sturgeon: extinct in the wild
The Yangtze River sturgeon, also known as the Dashi sturgeon, which is upgraded to the red catalog, is also a species endemic to the mainland. As early as 2020, there were media reports that after 2000, no naturally reproducing juvenile fish were found in the whole section of the river. Only 17 wild individuals collected by the Yibin Institute of Rare Aquatic Animals in the upper reaches of the Yangtze River remain, the number of wild individuals artificially preserved is very small, the natural population is basically extinct, and the species are extremely easy to become extinct. It was designated critically endangered in the earlier edition of the Red Catalogue.
For now, at least, we can't find any more traces of it in the wild. Fortunately than the white sturgeon, the artificial breeding research of the Dastenii sturgeon is progressing well. In the future, captive-bred Darden's sturgeon will be stocked in natural waters, promising to restore their populations. In Places like Wanzhou, Chongqing, there are rare fish domestication bases, and the efforts of researchers may one day help these creatures return to the wild.
3, Chinese sturgeon: more than 7 million fish have been released for more than 30 years
The flagship species of the Yangtze River, the Chinese sturgeon, has been declining in population in recent years, and artificial breeding and stocking have always been one of the important measures for the protection of Chinese sturgeon species. As of last year, a number of institutions, including the Chinese Sturgeon Research Institute, have released more than 7 million Chinese sturgeon in more than 30 years.
"At present, the Yangtze River Rare Fish Conservation Center, together with the supporting construction of the Chinese sturgeon sperm and histiocyte storage bank, is running better and better. It can basically ensure that the Chinese sturgeon does not follow the old road of extinction of the white-tipped dolphin, and the species will continue forever. Li Zhiyuan, general secretary of the party branch and deputy director of the China Sturgeon Research Institute, said.
4. Fish: The fisheries department once purchased individuals for 220,000 yuan
The other protagonist of this set of stamps, the fish, is also known as the Dasper. National Second-Class Wild Protected Animals were included in the IUCN Red List of Threatened Species in 2010 on the CriticalLy Endangered List.
Fish can lay millions of eggs at a time. In 2018, just an hour after the fishing in the waters of Heilongjiang, the fish was purchased by the local fisheries department for 220,000 yuan for breeding.
The results of the survey and monitoring of fish and other aquatic animal diversity in the Jiangsu section of the Yangtze River at the end of 2020 released by the Jiangsu Provincial Environmental Monitoring Center and Nanjing University recently show that a total of 81 species of fish were found in the Jiangsu section of the Yangtze River in 2020, an increase of 11 species compared with 2018, and the diversity of aquatic animals has recovered.
The monitoring results at the end of 2020 showed that in addition to the increase in fish species, finless porpoises were detected at 8 of the 28 monitoring points, and the detection rate was 28.6%. In addition, dashi was also found at 2 points in the Nanjing section of the Yangtze River.
Perhaps in the near future, we will see more sturgeon appearing in stamps, returning to wild rivers.
A little more news》》
What is the difference between extinction and extinction in the wild?
In fact, ICUN has been cautious about defining extinction and wild extinction. According to an earlier article on its website, there is no reasonable reason to question that the last individual of the species has died; When a thorough and thorough survey of known and/or expected habitats within the full historical range of the species has been conducted at an appropriate temporal frequency (day, season, year), and the survey has exceeded the life cycle and life form of the species at the appropriate time scale, and no individuals have been found, the species is presumed to be "extinct".
Similarly, the Red List defines "wild extinction (EW)" as when a species is known to survive only through artificial breeding, captivity, or as a naturalized population outside its historical distribution range; When a thorough and thorough survey of known and/or expected habitats within the full historical range of the species has been conducted at an appropriate time frequency (day, season, year), and the survey exceeds the life cycle and life form of the species at the appropriate time scale, and no individuals have been found, the species is presumed to be "extinct in the wild".
The Red List is very cautious about presuming species as "extinct (EX)" or "extinct in the wild (EW)". The Red List also establishes a list of species that are "probably extinct" or "likely to become extinct in the wild" for critically endangered (CR) species that have evidence of extinction or extinction in the wild, but cannot be classified as "extinct (EX)" or "extinct in the wild (EW)" until confirmed by prescribed standards and procedures.
Source: Upstream News