Is the Yangtze River paddlefish a vertebrate? IUCN has also re-evaluated the global sturgeon. Known as the "King of Freshwater Fish in China", the Yangtze sturgeon was officially declared extinct, and many people felt sorry for it. Is the Yangtze River paddlefish a vertebrate?
Is the Yangtze River paddlefish a vertebrate 1 What is the Yangtze River paddlefish?
As can be seen from the name, the Yangtze River paddlefish is a unique species in China, and they live in the Yangtze River. The Yangtze sturgeon and the Chinese sturgeon are not the same species. The Yangtze sturgeon is 2-3 meters long, weighs 200-300 kilograms, and the maximum length can reach 7.5 meters, also known as Chinese sturgeon. China swordfish, also known as China swordfish, is the largest freshwater fish in China. Because its snout looks like a trunk, it is also called elephant fish.
Sturgeon is a very old cartilaginous fish and one of the oldest vertebrates on the earth. Its origin can be traced back to Devonian more than 400 million years ago, when the ancient cod differentiated into the earliest sturgeon, which was one of the 27 remaining sturgeons in the Yangtze River. It appeared in Cretaceous (1 100 million years ago) and lived in the same era as Tyrannosaurus Rex. As early as the Western Zhou Dynasty, there were records of paddlefish. There is a famous saying of money in the Book of Songs: there are bream, bream and carp. It was built to sacrifice it, not to do great things.
Tuna is China's ancient name for the white sturgeon. As early as the Western Zhou Dynasty, there were poems about the use of the white sturgeon in sacrificial activities. Why is it the king of fresh water? As early as the Three Kingdoms period, there were detailed size records. At that time, one foot was about 0.242m, and 7-8 feet was about 2 m, indicating that the sturgeon was still relatively large. However, according to modern records, the longest sturgeon can grow to about 3 meters and weigh 250 kg -300 kg.
However, even the ancient species that existed for more than 100 million years experienced the fifth extinction, but it never escaped the end of extinction.
A harbinger of extinction
As early as February 23, 20 19, the Yangtze sturgeon (only 1 species) was officially declared extinct.
The international academic journal "Overall Environmental Science" published the research papers of experts from Yangtze River Fisheries Research Institute of Chinese Academy of Fishery Sciences. Wei Qiwei, chief scientist of Chinese Academy of Fishery Sciences, said that the Yangtze sturgeon is expected to be extinct on 20/2005 -20 10/0. However, this matter has not been publicly confirmed by IUCN. In June 5438 +2020 10, IUCN responded that the official news about the extinction of Yangtze sturgeon had not been released and updated, and "further discussion is needed in the future".
Although the World Conservation Union (IUCN) has not been officially announced, everyone knows it well and has been looking forward to this day for a long time. Because the Yangtze sturgeon has not been seen for many years.
It's been 19 years since it was last discovered.
On the first day of the Lunar New Year in 2003, scientists from the Yangtze River Fisheries Research Institute of China Fisheries Research Institute rescued a Yangtze sturgeon and installed a signal locator to track it. Unfortunately, however, when the ship hit the rocks, the radio signal of the released paddlefish disappeared. Everyone is depressed because they know that this trip is likely to be a farewell.
In the next ten years, the researchers did not find any more paddlefish, nor did they leave any artificially bred individuals. Previously, people still had a little expectation. "Some fishermen think that there are still paddlefish in some waters of the Yangtze River." It was not until 20 19 that 12.23 was declared extinct.
Why did the paddlefish become extinct?
This ancient species, which spanned more than 100 million years, escaped the fifth extinction. Why is it extinct now? It is conceivable that human beings can't escape the blame!
First, let's review the above. Since the Zhou dynasty, there has been a precedent for humans to capture the Yangtze River paddlefish for sacrifice, and there is also a saying among fishermen that "one thousand kilograms of wax is ten thousand kilograms". Among them, "Lazi" represents Chinese sturgeon, and "Elephant" refers to paddlefish. The vitality of the Yangtze sturgeon is very tenacious, which can be seen from its success in surviving the fifth extinction. However, due to human over-capture and environmental damage, it has never escaped this robbery.
So, is the number of Yangtze paddlefish very small from ancient times to the present? That's not true. In ancient times, fishing technology and demand were not so great. In the 1960s, there were still many paddlefish in the Yangtze River. It is very common on the boats of fishermen in the Yangtze River, and the state has not included the paddlefish in the list of protected animals. However, the high economy and the illegal fishing of the white sturgeon make fishermen catch a large number of white sturgeons unscrupulously, sell them at high prices and send them to the human table as delicacies. At that time, the annual catch of paddlefish was as high as 25 tons.
Due to the trend of profiteering, more and more people have joined the industry of catching white sturgeon. Until the 1970s, only 2.5 tons of paddlefish were caught every year. The decrease in catch makes fishermen even crazier. In order to ensure their own interests, they even use smaller meshes to catch the larvae of the paddlefish. Therefore, the sturgeon has lost its growing season, and many fish that do not lay eggs are caught and sent to the table, so the number of sturgeon will naturally decrease rather than increase.
Overfishing is not the only human activity that affects the survival of Chinese sturgeon. And dam the river. The paddlefish is a migratory fish, which lives in the lower reaches of Jinsha River, but it goes to the upper reaches of Yangtze River every year during ovulation. In other words, every spring, the female Yangtze sturgeon will go upstream to Yibin to lay eggs in order to lay eggs smoothly. Fish eggs will grow down the river.
However, damming the river blocks the river that the white sturgeon needs to cross, which makes it impossible for the female white sturgeon to trace back to the upstream and downstream of the fish eggs, which directly leads to problems in the production of the Yangtze River white sturgeon.
Not only in China, but also in China, damming the river has an impact on the paddlefish. According to the research of IUCN, damming and other activities have an irreversible impact on the reproduction of fish in natural waters, leading to the extinction or endangerment of one fifth of freshwater fish in the world.
Is the Yangtze River paddlefish a vertebrate? Another endemic species in China, ACIPENSER Changjiang, was declared extinct and failed to enter 2020. A research paper (pre-proof) published online by the international academic journal Science of Total Environment recently revealed this news.
The correspondent of this paper is Dr. Wei Qiwei, chief scientist and researcher of Changjiang Fisheries Research Institute of Chinese Academy of Fishery Sciences, and the first author of this paper is Dr. Zhang Hui.
The researchers said in the paper that it is estimated that the Yangtze sturgeon will be extinct in 2005-20 10. The pre-proof of this paper was published on 20 19 19. In addition to the extinction of the Yangtze River sturgeon, the Chinese sturgeon and the Yangtze River sturgeon endemic to China are still rated as "extremely dangerous".
The paddlefish is the largest freshwater fish in the world, with a maximum length of 7 meters. There is a saying among fishermen in Sichuan that "ten thousand catties of elephants carry wax"-"wax" refers to Chinese sturgeon and "elephant" refers to white sturgeon. This is a big guy.
To tell the truth, sturgeon is ugly. Its head, back and tail fins are all blue-gray, and only its abdomen is white. Sturgeon is naked and has no cover. Only one primitive scale called hard scale grows on the caudal fin.
Its kiss is long and sharp, so it was also called "elephant-nosed fish" by the ancients; The mouth is on the ventral side of the head, and there is only a row of tiny teeth in the mouth. Nevertheless, sturgeon is still fierce and can eat and swallow all kinds of small fish. Sturgeon has a big gill cover and a big mouth, but its eyes are very small, which is a bit funny and grows in front of the mouth near the back of the head.
The sturgeon's tail is also very personal-it is curved and the tail spine is bent upwards. If you dissect the sturgeon, you can also find that its spine is primitive, supported by a rod-shaped notochord, and most of its bones are cartilage. These body structures remind you that it is really old. For hundreds of millions of years, the white sturgeon has been stagnant. Some fossil studies show that the earliest sturgeon species fossils can be seen in the late Jurassic.
Chinese sturgeons lay eggs in the Yangtze River, and then they will take their young fish to the far sea. But the paddlefish is different. It has basically spent its whole life in the Yangtze River, and has been to the Yangtze River estuary at most. The spawning ground of ACIPENSER sinensis is located in the lower reaches of Jinsha River and the main stream of Yangtze River above Chongqing. Mature individuals have the habit of migrating upstream before the breeding season.
As a huge fish that is not outstanding, the paddlefish is "silent". Except the fishermen who deal with the Yangtze River, it is difficult for most people to see the live paddlefish. It doesn't have such a loud name as "Chinese sturgeon". If you can't see or understand it, even fewer people care about its fate.
There are many reasons for the population decline. The paddlefish only live in the Yangtze River. As the flagship species at the top of the food chain in the Yangtze River, its number is small and it is more susceptible to human activities. The deterioration of ecological environment, the decline of biological resources, high-density shipping, water conservancy projects, illegal power grids, hooks ... all these make the situation of sturgeon more and more difficult.
On June 5438+February 1 1 day, 2002, a female paddlefish with a body length of 330 cm and a weight of 1 16 kg was captured by fishermen in Xiaguan waters of Nanjing, Yangtze River. This ACIPENSER ACIPENSER is seriously injured, with several rolling hooks on its body and a wound about 22 cm long in its jaw.
This is the only living paddlefish found in the world in recent 10 years. At that time, the Ministry of Agriculture ordered the rescue at all costs.
However, at the beginning of June 5438+ 10, 2003, this paddlefish was declared dead. The experts tried hard for a month, but failed to revive it. At that time, the media wrote: No one knows if this is the last white sturgeon on earth.
In 2009, IUCN assessed the endangered species of the Yangtze River paddlefish as "extremely dangerous". But for many years, the Yangtze sturgeon has never appeared in the hard search of fishermen and scientists. No one could have imagined that this might be the last time people discovered the Yangtze River paddlefish. If you lose this fish, you lose the whole species.
Netizen lamented: We have never met, and I heard it was farewell. The news of "the extinction of paddlefish" is distressing:
Recently, the Ministry of Agriculture and Rural Affairs issued a notice to implement the 10-year fishing ban plan of the Yangtze River in the natural waters of the main stream and important tributaries of the Yangtze River except aquatic nature reserves and conservation areas for aquaculture.
Under the rapid and extensive economic development model in the past few decades, the biological integrity index of the Yangtze River has reached the worst "no fish" level. Therefore, it is extremely urgent to realize the ban on fishing and let the Yangtze River recuperate.
The Yangtze River is an important ecological treasure house in China, with more than 4,000 species of aquatic organisms, and it is one of the rivers with the richest aquatic biodiversity in the world. In 1988 list of national key protected wild animals approved by the State Council, there are 9 species of fish in the Yangtze River basin, namely the first-class protected animals, namely ACIPENSER sinensis and ACIPENSER Changjiang.
In addition to the extinction of the Yangtze River sturgeon, the Chinese sturgeon and the Yangtze River sturgeon endemic to China are still rated as "status" by IUCN. On 20 17 and 20 18, the Ministry of Agriculture and Rural Affairs successively launched the Chinese sturgeon rescue action plan and the Yangtze sturgeon rescue action plan.
According to Sina Weibo @ People's Daily, the implementation of the 10 year fishing ban plan in the Yangtze River will be the largest fishing ban in the history of the Yangtze River. As the ancients said, fish and turtles can't be eaten without counting, but due to overfishing, the Yangtze River has fallen into a "fish-free" situation.
Fish should be released, and people should reflect. There is no fish when fishing is exhausted, and the law is respected. The rise and fall of fish is essentially the indicator light that nature lights up for development. Give the Yangtze River 10 rest period, and the Yangtze River will bring vitality to the world.
Is the Yangtze River paddlefish a vertebrate? 3 The length of the paddlefish is 2-3 meters, the weight is 200-300 kilograms, and the longest is 7.5 meters. It is one of the largest freshwater fish, named after its light body color. Also known as Qin fish and Chao Jian fish, it was called tuna in ancient times. The body length is spindle-shaped, and the upper and lower jaws have fangs; The length of the kiss sword is 1.5 ~ 1.8 times the length of the back of the eye. The kiss part gradually widens from front to back, the front end is blunt, narrow and flat, and the base is thick. The body has no bony disc-shaped large hard scales; There is only a row of prickly scales on the upper edge of the caudal fin, the back is light purple-gray, and the abdomen and fins are slightly white and pink. [4]
The body of ACIPENSER sinensis is spindle-shaped, with a slightly flat front, a stout middle and a slightly flat back. The head is extremely long, more than half of its length, with plum blossom traps on it. Kiss the ventral surface of the head, and the ventral surface can stretch freely. There is a record in ancient books that "the mouth of sturgeon is under the jaw, and the person with long nose cartilage is also", which makes a concise summary of the ecological characteristics of sturgeon. The upper and lower jaws have small, pointed teeth; A pair of kissing whiskers, short, located on the ventral surface.
A pair of small eyes with small beards are located on the ventral side of the kiss. The oral fissure is large, arc-shaped and elastic, and is located on the ventral side of the head. There are two external nostrils on each side of the head. The whole surface of the head membrane is densely covered with many fine plum-blossom sensory nerve cells. The lateral line of the body is complete, the tail is curved, the upper leaf is long, the lower leaf is short, the back of the upper leaf has spiny scales, and the body surface is smooth and scaleless.
The upper leaf of caudal fin has 8 prismatic scales, which extend backward to the upper leaf of caudal fin. The dorsal fin starts from the back of the ventral fin and consists of unbranched fins. The caudal fin is curved, the upper leaf is developed, and there is a row of prickly scales in the front edge. The intestine is short, and there are 7 ~ 8 spiral valves in the intestine. The head, back and tail fins are blue-gray, and the abdomen is white.
The main difference between Chinese sturgeon and David sturgeon is that the body and head are bare, there is no bone plate covering, and the upper and lower jaws have fine teeth. Its body shape is also very strange, long spindle-shaped, flat before and slightly flat after. The length of the head is more than half the length of the body. The kiss is long and sharp, like a sword, sticking out at the front end of the head. There are wide and soft membranes on both sides of the kiss, and a pair of short and thin whiskers on the ventral side.
The mouth is very big, located on the ventral surface of the head, horseshoe-shaped and retractable. The branchial foramen is also very large, and there is no gill cover, but the eyes are very small. There are spray holes behind the eyes. The body surface is smooth and scaleless, or only traces of degenerated scales are scattered all over the body. The caudal fin is curved, and the upper leaf is longer than the lower leaf. The head, back and tail fins are dark gray, and the abdomen is white. There are many plum-shaped nerve cells on the whole surface of the head membrane. The skin is smooth and soft, and there are many branches like twigs on both sides of the body. Large with room 1.