This article was published in Sanlian Life Weekly, No. 5-6, 2020, the original title is "White Sturgeon and Those Endangered Yangtze River Fish", it is strictly forbidden to reprint it privately, and infringement must be investigated
Since 2006, ambulances for the white sturgeon have been floating on the Yangtze River, and a complete emergency system has been running at all times, but the white sturgeon may have been extinct as early as 2005, and humans have lost the last opportunity to save the species. More than a decade later, Wei Qiwei issued a paper inferring the extinction of the white sturgeon, but he did not want to sing an elegy, he hoped that people would notice that in the latest Yangtze River basin scientific expedition, 140 historically endemic fish species have not appeared, and the remaining flagship species, such as porpoises and Chinese sturgeon, are in jeopardy.
Reporter/Wang Haiyan
Photography / Zhang Lei
After the total ban on fishing on the Yangtze River in 2020, all fishermen in Dongting Lake will have to switch production and go ashore
Fishing vessels are being destroyed
The awkward position of the white sturgeon
On December 23, 2019, the international journal Science of the total environment published a paper online that inferred the extinction of the white sturgeon. Wei Qiwei knew that it was a bomb, and what he could not predict was what the consequences of throwing this bomb would be. Wei Qiwei is the chief scientist of the Yangtze River Fisheries Research Institute of the Chinese Academy of Fishery Sciences (hereinafter referred to as the "Yangtze River Institute"), and the corresponding author and instructor of the paper. In the days that followed, Wei Qiwei was indeed overwhelmed by the influx of phone calls, and sometimes he was still being interviewed at 12 o'clock at night.
However, many media reports have even mismatched images of white sturgeon, and images of spoon-sturgeon from North America are widely used. Spoon sturgeon (polyodonspathala) and white sturgeon (psephurus gladius) although from the same family, but belong to different genera, the difference in appearance of the two is obvious: spoon sturgeon has a long snout, the outstretched part from narrow to wide, shaped like a duck's beak, so also known as duck-billed sturgeon; white sturgeon also has a long snout, but the outstretched part from wide to narrow, shaped like a sword, so the folk also have the name of "swordfish".
Sturgeon have a very special place in the evolutionary history of fish, as a primitive fish, they existed on earth at the same time as dinosaurs 200 million years ago, all distributed in the holactic region (biogeographic concept, mainly in today's northern hemisphere). Some argue that sturgeon all over the world originated in the freshwater waters of East Asia and spread across north America through the Pacific Ocean. About 34 million to 75 million years ago, the white sturgeon was widely distributed on earth, but then most of the primitive fish were gradually replaced by Cenozoic bonefish, one of the few sturgeon that has been conservatively and stubbornly continued to this day.
Biologists are hard not to be attracted to sturgeon, most of which are huge in size, weigh hundreds of pounds, and can continue to grow even after maturity, making them the king of freshwater fish. Today, the world's sturgeon belongs to two families, acipenseridae and polyodontidae, and the Yangtze River once had both polyodontidae white sturgeon and acipenseridae Chinese sturgeon and Yangtze River sturgeon, and these three sturgeon once existed only in China. According to zoologist Bingzhi in the 1950s, fishermen in Nanjing caught a 7-meter-long white sturgeon weighing up to a ton, and if this record is accurate, the white sturgeon was one of the largest freshwater fish in the world.
Even so, the media is forgivable for using the wrong photo, because so far, this ancient Yangtze River fish has not left a clear image of the world in a healthy state. Although in the documents promulgated by the State Council in 1983, the white sturgeon and the Chinese sturgeon (acipenser sinensis) and the Yangtze River sturgeon (acipenser dabryanus dumeril) were listed as first-class protected animals at the same time, but the Chinese sturgeon began to be artificially bred and released as early as 1983, that is, the release of fry into the Yangtze River, and the artificial breeding of the Yangtze River sturgeon was also steadily advancing, but the protection of the white sturgeon was difficult to promote for a long time.
The status of the white sturgeon was indeed very embarrassing, according to the first Yangtze River Basin Biological Survey in the 1970s, although at that time the country could catch about 25 tons of white sturgeon per year. However, compared with the larger Chinese sturgeon, the white sturgeon is still "very small and scattered, only occasionally catching 1 to 2 tails, so it cannot constitute a fishery". In different areas of the Yangtze River Basin, there have been fishermen who specialize in fishing Chinese sturgeon, and even in special years there was a "Chinese sturgeon roe" production task, but the white sturgeon is more as a "miscellaneous fish" is accidentally caught, and the economic value is not prominent.
Although the folk proverb is called "Thousand Pounds of Wax (Chinese Sturgeon) Ten Thousand Pounds of Elephants (White Sturgeon)", this is more like a description of the extreme individuals of the two. Since doing sturgeon research in the 1980s, Wei Qiwei has noticed that mature Chinese sturgeon that migrate from the sea to the middle and upper reaches of the Yangtze River generally weigh more than 500 kilograms, but the adult white sturgeon is more than 200 kilograms. This means that most of the time the individuals of the white sturgeon are smaller than the Chinese sturgeon, and are not as striking as the latter. In the summary collection of the survey in the 1970s, the description of the white sturgeon is only a few pages, far less than the Chinese sturgeon and the Yangtze River sturgeon, which can also be seen that people know far less about the Chinese sturgeon and the Yangtze River sturgeon, and their life cycle, migratory habits, life history, spawning sites and other information are very scarce.
White sturgeon is also described as "swimming, fierce, gluttonous", and in 1975, people even found a 3-meter white sturgeon stomach that weighed 14.5 pounds of grass carp. Considering that the Chinese sturgeon did not eat during the migration of the Yangtze River, the white sturgeon was once supposed to be the top hunter in the Yangtze River, and the natural population was not large and difficult to domesticate. In a 1996 paper, Wei did mention that they had tried to breed white sturgeon many times, but without success, not even raising white sturgeon for more than a month. For various reasons, it has exacerbated the difficulty of rescuing white sturgeon, and at the same time reduced the importance that people once attached to the rescue of white sturgeon. Wei Qiwei told me that when gezhou dam was built, there was a discussion of "saving fish", but the fish discussed at that time were mainly concentrated in the four major fish (grass carp), Chinese sturgeon and Yangtze River sturgeon, and the white sturgeon did not even have much opportunity to be discussed.
Wei Qiwei began to study sturgeon in the 1980s, and today, although his students write papers about white sturgeon, they have never actually seen white sturgeon
Cliff extinction
He Baobing, a former Yangtze River fisherman, now works as an ranger at the Chinese Sturgeon Sanctuary in Yichang, Hubei Province, to combat illegal fishing. He Baobing's hometown was in Zigui, Hubei Province, and his family ran boats for three generations, and it was only in his generation that he began to fish in the Yangtze River section between Wuxia and Xilingxia, and immigrated to Yichang in 1995.
His deepest memories of the white sturgeon came around 1985 in the winter month of the lunar calendar, the flood of the Yangtze River, ushering in the season of clear water. He Baobing remembers that that year, for a whole month, every morning in his fishing nets there were always a few white sturgeons of about ten to 30 pounds, which they were locally called wooden mules. He Baobing used a three-layer gillnet with a 12-meter sewage and 12 centimeter mesh, and the fish on the net were almost all dead, "because its mouth (actually the snout) was very long, and the mouth died as soon as it poked into the net." Other fishermen also said that the white sturgeon is "the most delicate kind of fish" and "dies on the Internet, dies when hooked, and cannot be fed".
Their local fishermen don't really like to catch white sturgeon, and even call it "dead mermaids" because legend has it that they have bad luck in hitting scaleless fish. He Baobing was having a difficult life at that time, and he would sometimes throw away the dead white sturgeon fish he caught, sometimes he would spit out the kiss, pretend to be a fat fish, and take it to the market to sell. At that time, the white sturgeon was already a protected animal, but the management was not strict, just in the year when He Baobing saw the white sturgeon in large numbers, some of his neighbors had caught more than 300 pounds of white sturgeon, still alive, raised in a pond, called the local fishery administration, but after the fishery government took a photo, there was nothing to do, and instructed the fishermen to dispose of it themselves.
Among He Baobing's colleagues, Yang Niangao, who has been fishing in the Yichang River for generations, also has memories of white sturgeon. Around 1985, Yang Niangao hit a white sturgeon and called the fishery administration, and the government department sent a car to pick up the fish. Yang Niangao didn't know how heavy the fish really weighed, only that it was carried from the river to the highway, and 5 people were carried on stretchers, and they were breathless. The fish were transported by pickup trucks, and plastic sheets were enclosed in the carriages to make temporary pools. Yang Niangao remembered that because the fish was too big, the head pressed down, the tail was cocked, the tail was pressed down, the head was cocked again, and finally had to specially free up people to press in the carriage to ensure that the white sturgeon had been absorbing water.
Yang Niangao family is also a generation of fishing, the old people often say that the white sturgeon is seven (month) up and eight (month) down, this up and down season, the white sturgeon is usually in the deep water of the river straight forward, rarely stop, so the strength is large, will break the net. But in winter, the white sturgeon will also walk into the shallow waters of the river, or jump out of the river, as if to take a breath or take a turn. The white sturgeon carried away by 5 people was the last time Yang Niangao saw this species. In almost the same year, yang Niangao's current colleagues also caught white sturgeon for the last time, weighing 120 pounds. The former fisherman was impressed by this fish, because according to the policy, the fishery government should buy back such fish at a price of 8 to 1 yuan per catty, but after he handed over the fish to the fishery administration, the fishery government has not paid him, so he is still worried about it.
Regardless of the white sturgeon memories these fishermen have, one of the common points is that after some years in the 1980s, this ancient Yangtze River fish, although not dense, but at least common, suddenly disappeared without a trace.
Specimens of Chinese sturgeon in the Museum of Aquatic Biology of China
This folk impression is also reflected in the academic community, according to Wei Qiwei's later statistics, from 1981 to 2003, there were only 210 relatively confirmed large individual white sturgeon sighting reports in the whole Yangtze River Basin, and 2003 was also the last time humans witnessed and contacted white sturgeon. In January of that year, in Nanxi County, Yibin, Sichuan Province, a white sturgeon more than 3 meters long crashed into a large net of fishermen and was injured, and experts, including Wei Qiwei, rushed to the scene for treatment. Zhou Liang, director of the Institute of Rare Aquatic and Terrestrial Animals in Yibin, Sichuan Province, also participated in the treatment. He told the journal that the fish was not particularly badly injured at the time, and that the personnel at the scene had considered whether to leave it for scientific research.
But just before this fish, in December 2002, a white sturgeon more than 3 meters in Nanjing was injured and treated, and after 29 days of artificial breeding, it crashed into the pipe of the pool and died. Less than a month apart, people did not dare to risk leaving this white sturgeon in Yibin. Therefore, after the successful treatment, the expert group at the scene decided to release and track the white sturgeon with sonar signs, hoping to find its kind and conduct more research. The experts involved in the rescue were mainly from the Yangtze River Institute, which did not have a research vessel at that time, using a small speedboat provided by the fisheries department, and on the fourth day of the tracking, the speedboat hit the reef, and the next day was Chinese New Year's Eve, so after two days, when the speedboat was repaired and returned to the river, the white sturgeon had disappeared into the vast river. The group searched back and forth on the Yangtze River for several months and never received any more signals from it.
After the disappearance of this white sturgeon, in 2005, with the approval of the State Council, the original "Yangtze River Hejiang-Leibo Section Rare Fish National Nature Reserve" was renamed "Rare endemic fish national nature reserve in the upper reaches of the Yangtze River", and the scope of protection was also expanded from the original 420 km of main stream to 1162.61 km including main streams and tributaries. A project for the rescue and research of white sturgeon was also officially launched the following year, and the leader of the project was Wei Qiwei. He told me that it was through this project that they had a dedicated research boat with a car and an emergency care network for the white sturgeon.
Subsequently, from 2006 to 2008 and from 2008 to 2011, the Yangtze River Institute launched two large-scale scientific expeditions to search for white sturgeon in the entire Yangtze River basin through fishing and sonar, but they never saw the huge figure again. No one, including these white sturgeon researchers, expected that the white sturgeon in 2003 would become the last white sturgeon in human contact.
The white sturgeon specimen in the China Museum of Aquatic Biology is the only place where people can see this biological entity
It was not until a few years later, when reanalyzing the sightings of the 1980s and 1990s, that Wei Qiwei clearly realized that the white sturgeon had become functionally extinct in 1993, that is, it had permanently lost its reproductive ability and would inevitably become extinct in the future. But exactly what caused the white sturgeon to go extinct, he did not have a definite answer.
According to a small number of studies in the past, white sturgeon will live in the main stream, lakes and even offshore waters of the lower Reaches of the Yangtze River, and like most sturgeon, migrate to the upper reaches of the Yangtze River to spawn after maturity. In 1980, researchers from the Sichuan Fisheries Research Institute discovered a natural spawning ground for white sturgeon in the river section about 500 meters across the river from Baixi Town, Yibin County, Sichuan Province, which is also the only white sturgeon spawning ground found by humans with conclusive evidence. This means that after the completion of the Gezhouba Hydropower Station in Yichang in 1981, the reproductive migration route of the white sturgeon was at least partially blocked.
In order to study the potential impact of the Gezhouba hydropower station on white sturgeon, in a paper published last year, Wei Qiwei's team divided the white sturgeon above and below the Gezhou Dam into two groups for mathematical modeling, and the results showed that only the population on the dam underwent a functional extinction process, but not the population under the dam. Combined with historical data, the team believes that the key factor contributing to the extinction of the white sturgeon below Gezhouba may be fishing and habitat degradation, but why the upstream white sturgeon completely lost their reproductive ability after 1993, the team can not clearly answer, after all, the human understanding of the white sturgeon is actually in the rather preliminary stage.
A relatively certain fact is that after 1986, the entire section of the Yangtze River has not been monitored to hatch the white sturgeon juveniles that year. Although it is difficult to describe exactly how the dam will affect the reproduction of white sturgeon, Wei Qiwei believes that the impact of the dam on such large migratory fish must be the first. Wei Qiwei told me that unlike mammals, the reproductive activities of fish are often strictly limited by natural conditions, such as water temperature, riverbed structure, river bottom, water level, sand content, flowing water situation and speed, and other complex hydrological conditions, which will directly affect the breeding activities of fish. Even domestic fish such as grass carp, when naturally breeding in the wild, are extremely sensitive to changes in hydrological conditions, such as every year when the flood peak comes, the surface water rushes into the river, the fish immediately get excited, begin to reproduce and spawn, if there is no flood peak, then do not move. This is also why some fish have to go through a long migration to find suitable spawning grounds, and the construction of hydropower stations will permanently change the character of the Yangtze River and also change these spawning grounds.
Rare fish in the precarious Yangtze River
Although there is still little hope, all those who pay attention to the extinction of the white sturgeon are actually mentally prepared. Wei Qiwei hopes that people will be able to turn more attention to those species that are in danger, such as the remaining Chinese sturgeon and Yangtze River sturgeon in the Yangtze River. In the minds of many people, the Chinese sturgeon has been safe and secure, and even some reports of artificial breeding and release can be seen every year, but the actual situation may be somewhat inconsistent.
The artificial breeding of Chinese sturgeon made a preliminary breakthrough in 1983, but Wei Qiwei told me that since then, until 1996, the artificial breeding technology has not been broken, and chinese sturgeon seedlings have to be put into the Yangtze River in the "splash" stage, that is, the very early stage of the tail fin and dorsal fin that have not yet been separated, and it is difficult to survive. In 1996, there was a breakthrough in the artificial breeding technology of Chinese sturgeon, so in 1997, the seedlings of Chinese sturgeon released into the Yangtze River reached 10 centimeters, and 20,000 were released. Subsequently, in 1998 and 1999, a total of 120,000 Chinese sturgeon with a length of 10 centimeters were put into the Yangtze River, and these batches of fry were partially marked by the release personnel. But even on such a large scale, in the following years of testing at the Yangtze River estuary in Shanghai, the scientific research team found that the artificial release of Chinese sturgeon only accounts for about 3% of the total chinese sturgeon, and the population replenishment effect is not ideal. This is also the only evaluation of the effects of the release of Chinese sturgeon.
After the century stocking in 1999, the stocking of Chinese sturgeon stopped for a while, and it was not until 2003 that a special fund was restarted, and from then until 2008, the total number of Chinese sturgeon of no more than 100,000 was put into the Yangtze River, and the number of stockpiles decreased year by year. In 2008, scientific research and fishing was halted because there were less than 200 wild breeding populations in China, and the natural population was in danger. But in fact, at that time, the chinese sturgeon full artificial breeding did not break through, still need to catch mature broodstock from the Yangtze River every year, obtain eggs and sperm to achieve reproduction, scientific research fishing stopped, the situation of various scientific research institutions became no fish to release.
Taking the Yangtze River Institute as an example, their chinese sturgeon second-generation breeding technology was breakthrough in 2012, and reached the scale in 2015. But at this time, there is no money for Chinese sturgeon, and various scientific research institutions are facing the situation of no money to raise fish, which is why the chinese sturgeon release news seen in recent years is mostly hundreds or thousands. Wei Qiwei believes that such an order of magnitude, the supplement to the wild population of Chinese sturgeon is not even drizzle, and many people still hope for the natural reproduction of Chinese sturgeon.
In fact, before the construction of Gezhouba in 1981, there were at least 16 historical spawning grounds for Chinese sturgeon in the 800-kilometer section of the upper Reaches of the Yangtze River to the lower reaches of the Jinsha River. However, after the construction of gezhou dam, the spawning ground of Chinese sturgeon is relatively certain, and only an area of about 5 kilometers under Gezhou dam remains. There has been natural breeding activity every year since 1981, but since 2013, this spawning ground has not detected any natural breeding behavior for many years in a row, except for one spawning activity detected in 2014. During an interview in Yichang, inspector Xie Baobing told me that a few months ago, he also saw the Chinese sturgeon jumping high above the water, and he was so excited that he shouted to his companions, "Hey, the Chinese sturgeon is coming!" "But the spawning season in 2019 has long passed, and the Chinese sturgeon that has traveled thousands of miles to the Yangtze River have still not been able to complete breeding this year."
Wei Qiwei said that there may be two reasons for this result: first, the Chinese sturgeon that migrate to Yichang every year is below 50 heads, and when it is small, there are less than 20, which is too small; second, in the river below 20 degrees Celsius, the Chinese sturgeon can complete gonadal development, but during the traditional spawning peak in late October, the Yangtze River in the Yichang section is calm and wide, and the water temperature is 22 degrees Celsius.
Compared with the Chinese sturgeon, the natural reproduction of the Yangtze River sturgeon is even worse, this relatively small sturgeon, long-term settlement in the upper reaches of the Yangtze River, has not been monitored for 20 years natural reproduction. However, unlike the Chinese sturgeon, They have done simulations, under the right conditions, these Yangtze River sturgeon can naturally breed, and the historical spawning grounds of those Yangtze River sturgeon in the Yangtze River, at present, the hydrological conditions are within acceptable fluctuations. At present, the Yangtze River sturgeon has not yet found wild breeding, this is because the number of Yangtze River sturgeon in the river is too small, most of them are hunted, objective estimates, as long as there are economic conditions, the Yangtze River sturgeon can rebuild the population in a relatively short period of time.
In contrast, the population reconstruction of the Chinese sturgeon is much more difficult. For example, the Chinese sturgeon, a close relative of the white sturgeon, did not eat during the two-year-long migration, crossing the sea and fresh water, and the life history is extremely complicated. Wei Qiwei said that the female adult Chinese sturgeon in the natural environment should be more than 500 pounds to have enough energy to complete the migration. But of the 700 sturgeon in the Yangtze River Institute, only two reached 400 pounds, and the rest weighed 200 pounds or less, and most of them were sick.
In addition, the Chinese sturgeon was first at the age of 14, and on average around the age of 18, it would migrate from the sea to the Yangtze River, and if the batch of Chinese sturgeon released after marking in the late 90s returned, the effect evaluation could already be completed. But because of the ban on scientific fishing, the work cannot be started at this time. According to the latest statistics of the Yangtze River Institute, there are only 3,000 Chinese sturgeon in total, which are 10 to 20 years old in the country, scattered in various scientific research institutions and private breeding bases. Because there is no special plan, these institutions have no obligation to release Chinese sturgeon, that is, they can stop the release of Chinese sturgeon at any time.
Therefore, in the eyes of Wei Qiwei, the Chinese sturgeon is still in danger.
Not only is the flagship species of the Chinese sturgeon threatened, Wei Qiwei told me that in 2017, the second scientific expedition to the whole Yangtze River basin was launched, and the preliminary results showed that there have been 140 species of Yangtze River fish that have been reported in history, most of which are highly endangered species, such as the largest individual can reach 100 kilograms of ale and the Sichuan white turtle has not been seen for many years, but has not been included in the IUCN Red List. And more fish, because of the lack of continuous historical data, whether the remaining species have gone extinct or are going extinct, and how to protect them, there is no answer.
Compared with these fish that have disappeared silently, the white sturgeon has been in contact with humans for a long time. In ancient Chinese texts, the white sturgeon is often called sturgeon or sturgeon, mixed with Chinese sturgeon, of which the records of white sturgeon include that Guo Pu of the Western Jin Dynasty believes that the "tuna" in the "Classic of Mountains and Seas and the Dongshan Classic" is also "like a carp and has a long nose, and the body has no scales". The Han Dynasty "Han Shi Wai Biography" has the sentence "In the past, the boya drum and the harp and the obscene fish listened", and the high temptation was annotated as "the obscene fish is long, the head and body are half, the nose is white, the body is black, the mouth is under the jaw, and the body has no scales, out of the river", which is the description of the white sturgeon. In his commentary on the Huainan Zi Feng Commentary, Gao Fu also said that "the tuna, the big fish, from the West River in Mid-Spring march, get through the dragon gate is the dragon", which is consistent with the Description of the Northern Wei "Water Jing Zhuan River Water" "Erya" 鳣, 鲔也, out of gong cave, March then cross the dragon gate".
In the Western Zhou Dynasty, every year in the late spring, Tianzi would personally go to the tomb of the previous king and offer sturgeon as a sacrifice. Some opinions even believe that the allusion to the "fish leaping dragon gate" originally came from the migratory sturgeon, and it was not until later that the protagonist of the allusion was replaced by a carp. How the legend changed is difficult to verify, but these records confirm that the white sturgeon was widely distributed in many water systems and coastal waters, including the Yellow River, until the ecological changes occurred earlier in these water systems, and the white sturgeon gradually retreated to the Yangtze River, which should be its last refuge. (Intern Yue Ying also contributed to this article)
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