Source: People's Daily
Top left: Researchers at the Kunming Institute of Zoology, Chinese Academy of Sciences, conduct a field search.
Top right: Close-up of Dianchi Lake gold thread catfish.
Courtesy of Kunming Institute of Zoology, Chinese Academy of Sciences
Below: Sail Shadow of Dianchi Lake (taken in October 2019).
Photographed by Wang Zhengpeng
introduction
The ecological environment of Dianchi Lake was once destroyed, becoming one of the most polluted lakes in China. After years of unremitting treatment, in 2016, the water quality of the whole lake of Dianchi Lake rose from five categories of inferior to five categories, and the first to take the hat of "inferior five categories"; in 2018, it rose to four categories, the best in 30 years; in 2019, it continued to remain in category iv.
On January 20 this year, General Secretary Xi Jinping visited the ecological wetland of The Xinghai Peninsula of Dianchi Lake during his inspection in Yunnan to inspect the biodiversity display of Dianchi Lake, Fuxian Lake, Erhai Sea and Dianchi Lake. The general secretary pointed out that Dianchi Lake is a jewel embedded in Kunming, and it is necessary to show the momentum of not relaxing in the green mountains, and in accordance with the concept that the landscape, forest, field, lake, and grass are a community of life, strengthen comprehensive management, systematic governance, and source governance, and redouble our efforts to do a better job in the management of Dianchi Lake.
What would the ideal, or future, Dianchi Lake water body look like? At the exhibition site on January 20, a glass "ecological tank" attracted attention: snow white and elegant sea cauliflower bloomed on the water, Dianchi Lake golden thread catfish swam through, and the dorsal horn toothless mussel perched on the bottom of the tank.
"The miniature ecosystem composed of these three types of indigenous organisms is an ideal state that is expected to be achieved in the waters of Dianchi Lake in the future." Li Weiwei, deputy director of the Kunming Zoological Museum of the Chinese Academy of Sciences, who is responsible for the layout of the ecological tank, told reporters, "The protection and governance of Dianchi Lake has entered a new window period, and it has gradually shifted from engineering management to the return and reproduction of indigenous species." Dianchi Lake is more biodiverse, which is conducive to the formation of a three-dimensional and balanced ecosystem. ”
The Dianchi lake golden ray that shines in the sun is known as the "Dianchi Antique": it survived more than 3 million years ago when Dianchi Lake was formed. However, with the destruction of the living environment, the golden mackerel disappeared from the lake in the 1980s. With the breakthrough of artificial breeding technology in recent years, as well as the continuous development of breeding and stocking activities, the population of The Golden Line Catfish in Dianchi Lake has reappeared in the upper reaches of the Panlong River into the Yunnan River.
From endangered national second-level protected animals to the current artificial breeding capacity of tens of millions of tails; from withdrawing from the lake to re-entering the lake, helping the ecological governance of the Dianchi Lake Basin - the Dianchi Lake golden ray catfish, which ranks first among the "four famous fish in Yunnan", the change of fate is so closely related to the Dianchi Lake, which enlightens the current lake ecological environment governance and restoration.
The worry of disappearing
Dianchi issued an early warning
The babbling water is crystal clear, and flocks of Yunnan light-lipped fish, Kunming split-bellied fish and Dianchi lake golden-lined catfish are wandering with their heads and tails. Clusters of sea cauliflower float along the water, and the flowers dot the water.
In the late spring, the reporter came to Kunming Songming Black Dragon Pond, as if mistakenly entering the peach blossom source, and the mood was suddenly comfortable. Pan Xiaofu, an associate researcher at the Kunming Institute of Zoology of the Chinese Academy of Sciences, sighed: "In the past, five hundred miles of Dianchi Lake, all the rivers that flowed into Dianchi Lake were like this! ”
"Five hundred miles of Dianchi Lake, rushing to the bottom of the eye." Cloaked on the shore, the joy is vast and boundless..." The long link of the Qing dynasty Sun Hair Weng weng is still hanging on the pillar of the Grand View Tower on the edge of the Dianchi Lake, which makes many visitors think of it. But the accumulated pollution once overshadowed the plateau pearl. Pollution in Dianchi Lake peaked at the turn of the century, and people saw the "green paint" Dianchi lake water after the cyanobacterial outbreak. Many of the dianchi lake relics that were once there were only left in the literature or memory. The Dianchi lake golden thread catfish is an example.
Dianchi lake golden ray catfish commonly known as goldfish, small hole fish, adult fish like to eat small fish and shrimp, the first of the "four famous fish in Yunnan" - the other three are the Dali bowfish in the Erhai Sea, the white fish in Fuxian Lake and the big head carp in Nebula Lake.
The native Dianchi lake golden thread catfish disappeared in the 1980s. What is the reason?
"Water pollution is becoming more and more serious, indiscriminate fishing has been repeatedly prohibited, and competition is not enough for exotic species, and the survival and spawning environment of the Dianchi lake golden line catfish have changed drastically." Yang Junxing, a researcher at the Kunming Institute of Zoology of the Chinese Academy of Sciences who has been dealing with fish for 37 years, explained.
Dianchi golden herring is a "delicate" fish. From December to March of the following year, it swims to the springs around Dianchi Lake and in the underground dark rivers to spawn, the water temperature must be 18 to 20 degrees Celsius, and it must be clean water. It carefully lays eggs to the surface of underwater gravel and enters a 7 to 8-day incubation period, while the incubation period of the "four big fish" such as green, grass, silver carp and bighead carp is much shorter. This means that without the spawning environment of Longtan (the local name for spring pond), the underground river, or the spawning migration channel is blocked, the breeding of the Dianchi lake golden line catfish will be fatally hit.
At the end of 1969, the construction of land around the lake in Dianchi Lake began. After 8 months, after three battles of embankment building, drainage, and soil reclamation, the "Baqiao Smoke Willow", one of the eight scenic spots of Dianchi Lake, turned into black humus. In the end, 30,000 acres of land were built around the lake. Since then, many longtans have also been used as masonry ponds for irrigation and water, and since then, the channels into the Dian river have shrunk and polluted, and the golden line catfish has to leave the Dianchi Lake and remain in some surrounding Longtans.
For a long time, Dianchi Lake was a productive lake – when increasing aquatic production to "solve the stomach problem" was a top priority. Before 1957, Dianchi Lake was dominated by native fish. In the late 1960s, stocking of silver carp and grass carp became the mainstream, and in 1969 the catch of aquatic products was 3080 tons. It increased to 8 363 tonnes in 1975 and was mainly caught in Giant River Prawn and White Shrimp. In the 1980s, the exotic species of silverfish began to become the main product, and the production alone reached 3500 tons.
"It was not until 2010 that native fish species were stocked into Dianchi Lake from the perspective of water treatment, the artificially bred Dianchi Lake golden rayfish." Wang Yong, deputy director of the Fishery Administration Supervision and Administration Office of Dianchi Lake in Kunming, introduced that the "four big fish" introduced to enrich the "vegetable basket", especially the wheat ear fish brought with it, made the golden thread catfish unbearable.
"The 'fragility and delicacy' of indigenous fish such as the golden herring catfish in reproduction shows that they are highly dependent on the healthy water environment of Dianchi Lake. Over the years, we have deeply felt that the landscape, forest, field, lake and grass are a community of life, and this community is interlinked, and it is impossible to lack any link. In Yang Junxing's view, the withdrawal of the Dianchi golden thread catfish from the lake is actually an early warning to humans, indicating that Dianchi lake has been "sick".
It's not just the golden mackerel that has disappeared. In the 1960s, there were 26 species of indigenous fish in Dianchi Lake, and only 4 species remain in the lake today. At present, there are 15 species of indigenous fish species in the Dianchi Lake Basin that are endangered or vulnerable. "We should not underestimate these endangered indigenous fish species, because each organism contains hidden geological knowledge, rich evolutionary information, and valuable genetic information." Yang Junxing was worried.
Dr. Wang Xiaoai, who also works at the Kunming Institute of Zoology of the Chinese Academy of Sciences, understands biodiversity from the perspective of genetic diversity, "There is genetic diversity only when species are diverse, and the rich genes brought about by this are the resource bank for human beings to cope with various uncertainties." For example, to deal with various epidemic infectious diseases, etc., it is also necessary to use genetic research, and it cannot be ignored because it is 'useless' now, and 'species are used to hate less'. ”
The power of breeding
Seize the important opportunity to save the Dianchi Lake golden line catfish
One day in 2003, Yang Junxing received a strange transoceanic phone call. The other party claimed to be from the Global Environment Facility (GEF) and expressed its willingness to provide scientific research funds to fund research on the restoration of aquatic biodiversity in Dianchi Lake.
The call came from Tony Victor, biodiversity officer for east Asia and the Pacific at the Global Environment Facility, and the funding was issued by the World Bank as a grant — Yang Junxing's team had previously completed the artificial breeding of the Fuxian Lake squid, which attracted attention. With this funding, Yang Junxing turned his research to the Dianchi golden thread catfish, which he had long been "begging for".
In 2004, the Kunming Institute of Zoology of the Chinese Academy of Sciences established a rare fish breeding base in Dabanqiao, Kunming. Pan Xiaofu recalled that from the office of the institute to the base, you have to take the No. 74 bus first, transfer to the No. 11 bus after more than an hour, and then change to "Mo's", and the base is surrounded by continuous farmland.
With funding and a base, Yang Junxing's team began to look for fish in the wild. After traveling through the dragon ponds and streams scattered around Dianchi Lake, they eventually found small populations of wild golden-threaded catfish in Songming Black Dragon Pond and Muyang River.
"This is an important opportunity to save the Dianchi Golden Thread Catfish. Without the support of the Chinese Academy of Sciences, the Yunnan Provincial Development and Reform Commission, the Department of Science and Technology and other departments, we would not be where we are today. Now in the office reminiscing, Yang Junxing is quite emotional.
Scientific research is full of challenges. Dianchi lake golden herring survives well in the wild, but when it comes to the laboratory, it does not breed, and the sperm and eggs of the golden herring in the pond are always immature, cannot be artificially inseminated, and some fish do not even excrete sperm.
What do you need to eat to help them sexually mature? How do you make your bait recipe highly consistent with your "wild recipe"? How to artificially create an spawning environment? The researchers groped from scratch.
The Dianchi lake golden herring is active at night, and during the breeding period, researchers sleep on the mounds of fish ponds. "In scientific research, people will fish, and people can't fish." Pan Xiaofu has been stationed here since the establishment of the base, "Observing the fish at night is tired, and it is also fun to turn over and see the stars in the sky." In those sleepless nights, Pan Xiao gave the birth of his son Haoming: I hope to remember this pen in the vast Dianchi Lake.
Cold and summer, Yang Junxing's team has walked around the Dianchi Lake Golden Line Catfish for more than 3 years. "Fish can't speak, and during the breeding season they are used to hiding, and they can only accumulate by a little observation." Yang Junxing said.
Finally out of the woods! In 2007, more than 300 fry were bred in the laboratory. After exploring the sexual maturity law of golden thread catfish, the fertilization rate increased from 30% in one hour to 70% within half an hour. Also in this year, Yang Junxing's team received 6 million yuan of financial support from the Yunnan Provincial Government. Since then, research on embryonic development, the transformation and growth of feeding habits of juvenile fish has also progressed smoothly.
In mid-March, the reporter came to the fish base in Dabanqiao. In the hatchery, in a steel basin with a diameter of two or three meters, the juveniles of the Dianchi lake golden-threaded catfish are densely packed. "Fish eggs stick to the attachment, and from the initial breeding of 300 to tens of millions today, the endangered species of goldenrod have been preserved!" Dr. Zhang Yuanwei of the Kunming Institute of Zoology of the Chinese Academy of Sciences introduced.
Wang Xiao'ai, on the other hand, calls himself a "cell keeper" who "freezes" the cells of dianchi golden herring in liquid nitrogen at minus 196 degrees Celsius and restores its activity when needed. Not only dianchi lake golden thread catfish, she also gave more than 30 kinds of Yunnan indigenous fish to build a file to achieve cell level preservation.
Zhang Yuanwei mastered the hybridization technology of Dianchi golden thread catfish and carp, which is conducive to the promotion of industrialization, which means patents and benefits. Now in place of Pan Xiaofu in charge of the base, he said that he would not do it here just to figure out money.
In the south of Caiyun, known as the "biological kingdom", there are 594 species of indigenous freshwater fish, accounting for about 40% of the country, of which 138 are endangered. From these figures, it is not difficult to grasp the special significance of the work of rare fish breeding research. "There is global value in protecting biodiversity, and although my hair is gray, there are still many endangered fish waiting for us to study and breed." Yang Junxing said.
Swimming out of the laboratory, the Dianchi lake golden thread catfish will face two directions: returning to the ancestral world and purifying the water body of Dianchi Lake; artificial breeding can be developed and utilized sustainably, and "swimming" back to the public's table. Since 2010, the water body of Dianchi Lake has begun to release the golden ray catfish, which is the artificial breeding fry of Yang Junxing's team. How are they doing 10 years later?
Ecological governance
Restoring the "habitat" of dianchi lake golden thread catfish requires embroidery
During the warm spring season, a news item attracted attention: 36 pincer-billed storks appeared in the Dianchi Wetland.
In recent years, the wetland restored by Dianchi Lake has become a natural "bird's nest". The species of wild birds that are patronized are constantly being refreshed, including the endangered species of painted ibis, as well as more than a dozen species such as the tumbler sandpiper and the iron-billed sandpiper.
The governance of Dianchi Lake is a major event related to the overall situation of Yunnan and a key project for the construction of ecological civilization. From point source pollution control to watershed system governance, from single pollution control to pollution control and ecological restoration, over the years, Yunnan Province and Kunming City have persevered, and the treatment of Dianchi Lake has achieved remarkable results.
"People retreating into the lake and recuperating are the 'birth beds' of the biodiversity of Dianchi Lake." Pan Min, senior engineer of the Dianchi Plateau Lake Research Institute in Kunming, spoke highly of the treatment of pollution interception around the lake and "four retreats and three returns" (through the withdrawal of ponds, fields, retreats, check-out, to achieve the return of lakes, forests, and wetlands), "through engineering measures to solve the problem of exogenous pollution first, and then turn to lake water ecological governance, which is also the common experience of international lake governance." ”
Indigenous fish are indispensable in biologically balanced, ecologically healthy lakes. Since 2010, more than 1.8 million gold rays have been released to Dianchi Lake. At the same time, there are also indigenous fish such as Dianchi high-backed crucian carp, Yunnan light-lipped fish, and Dianchi silver white fish - most of them have experienced the "ups and downs of fate" that disappeared and reappeared in Dianchi Lake.
As the flagship species of Dianchi Lake, the prosperity of the golden thread catfish has a unique significance for the ecological chain of Dianchi Lake. "The golden mackerel is located in the upper echelons of the food chain of Dianchi Lake, preying on small fish and shrimp such as silver fish, thereby inhibiting algae outbreaks and helping the health of water bodies." Pan Xiaofu introduced.
However, after 10 years of release, the recovery of the population of the Dianchi lake golden herring is still not ideal. Although stocks of stocked golden herring have been found in the upper panlong River, "no small fry have been found, indicating that the artificially released fish may not have multiplied." Wang Xiao'ai said.
Why? Yang Junxing analyzed that one is that the number of releases is small, and finding a needle in a haystack in Dianchi Lake is like finding a needle in a haystack; the second is that the overall ecological environment of Dianchi Lake is not ideal - the migration environment of golden line catfish such as Longtan and Dark River is still blocked.
At the foot of Kunming's West Mountain, Pan Xiaofu and his reporters rushed to inspect a dragon pond that was said to be possible to breed golden thread catfish, but the scene was disappointing: the surging water of the dragon pond had dried up.
The "habitat" of the restored Dianchi golden-threaded catfish is obstructed and long. In the case of Longtan, for example, some of them have dried up and obliterated, and some have been cut off into water intakes. The Longtan connected to Tuna was once part of Dianchi Lake.
"If the engineering governance is effective and obvious, then the ecological governance and biodiversity restoration of Dianchi Lake must be embroidered for a long time." Pan Min said frankly.
In the late spring, the reopened Dounan Wetland Park is sparkling and swaying with water and grass. Aquatic plants such as sea cauliflower, calamus, and water lilies are dotted along the shore road, and the silver-edged wheat winter, Zhongshan fir, fire thorn and other qiao shrub plants are arranged in echelons. Egrets, silver gulls, and red-billed gulls are waiting for birds to become regulars; fish such as Dianchi lake golden-threaded catfish, Dianbaibai and silverfish swim here.
"We have a nursery rhyme in Yunnan: 'Sea cauliflower, white flowers, little dolls who love to bathe, clear water without mud or dirty... ' The survival of sea cauliflower and Dianchi lake golden rayfish needs a clean water environment, see if you can find it here." After listening to the explanations of the staff, parents and children could not wait to go to the surrounding area of the wetland and start a "treasure hunt" journey. Not far away, a couple is taking wedding photos.
It is hard to imagine that a few years ago, it was a mixture of greenhouses, fish ponds, and houses. Li Yingshu, deputy director of the Kunming Dianchi Lake Management Bureau, introduced that after 5 years of construction of the Dounan Wetland, on the basis of "four retreats and three returns", the breakwater that blocks the circulation of the lake is dismantled through landscaped methods, and while reconnecting the wetland with the Dianchi Lake, it makes full use of the ecological methods of indigenous fish and aquatic plants to purify the water body.
In Yang Junxing's view, the future fate of the Dianchi golden line catfish depends on the effectiveness of "comprehensive management, systematic governance, and source governance".
Long-term solution
Live up to the fish in Dianchi Lake, so that more people can benefit from ecological restoration
In 1638, the great traveler Xu Xiake entered Yunnan from Shengjingguan and stopped in Kunming. In this year, he wrote the "You Taihua Mountain Chronicle", which said that the goldfish "is no more than four inches large, the fat is in the middle, and the head and tail of gold are like a thread, which is the treasure of Dianchi Lake".
Under the Taihua Mountain, on the shore of Dianchi Lake, many places in Kunming intend to continue to write a historical frontier with the golden line catfish. Baicao Village, Biji Town, Xishan District, located on the edge of Dianchi Lake, is one of them. There are two dragon ponds in the village, one large and one small, and there have always been Dianchi golden line catfish to survive. The village is clean and tidy, and it is using the golden line catfish to create rural tourism.
When the reporter arrived, the longtan in the village had just been dredged. "The golden line catfish swim back to the dark river to hide, and after the construction is completed, tourists can see the wild golden line catfish, which is the highlight of our baicao village." Villager Wang Theory.
How to mobilize the masses to love and restore the living environment of the Dianchi lake golden line catfish? People do not live up to Qingshan, and Qingshan will certainly not live up to people. Green waters and green mountains are both natural wealth and economic wealth. Pan Min believes that when the masses benefit from it, more people will participate.
More than 10 years ago, Yang Junxing built a three-dimensional breeding model test field of "sea cauliflower-golden thread catfish-mussels", hoping to promote its application to the farmland around Dianchi Lake.
"Although the 'ecological tank' breeding model is good, it is a pity that it is a bit out of time." In the view of Zhou Wei, a retired professor at Southwest Forestry University, how to quickly make the water clear in Dianchi Lake was the most urgent task at that time, and the management of the breeding model of "flower fish mussels" was slow. Now, Zhou Wei feels that the time has come: "This model can not only allow villagers to earn income by selling gold thread catfish and sea cauliflower, but also purify the water quality of Dianchi Lake and promote biodiversity, which is worth promoting in Dianchi Lake's 'rotational grazing'." ”
A few years ago, the promotion of the "flower fish mussel" breeding model was not effective because of the lack of good seeds, as Yang Junxing himself said, "If you can't supply seedlings stably and in batches, how to let farmers settle down in this way?" Today, this is no longer a problem - after 13 years, Yang Junxing's team has finally developed a large-scale breeding variety "Catfish No. 1" based on the wild Dianchi lake golden thread catfish, which grows 40% faster than the wild variety, optimizes the intermuscular spines by 80%, and can be chewed and swallowed directly when cooked.
In May 2018, "Guiyou No. 1" was approved by the Fifth National Aquatic Origin and Fine Species Approval Committee, becoming the first new aquaculture species in Yunnan Province to be certified by the state. In the previous 10 years, this committee approved 182 new aquatic varieties, but Yunnan was left behind, and the abundant fish resources could not be transformed into industrial advantages.
Now that the variety problem is solved, how about marketing?
More than 200 kilometers out of Kunming, arrive at Huize County, Qujing City. Walking through the hinterland of Wumeng Mountain, tracing up the Bison Stable River, all the way to the noise of the water, the mountain flowers, and come to the breeding base of The Dianze Aquatic Company.
Li Jianyou, the person in charge of the breeding base, has long cooperated with Yang Junxing as a team to promote the industrialization of Dianchi lake golden thread catfish. The base is dominated by sturgeon, with more than 40 species of indigenous fish from Yunnan farmed. These indigenous fish are often released into the nearby Niulan River, which is also the starting point of the Dianchi Lake water replenishment project.
Although the market price of Dianchi Lake golden line catfish is as high as 670 yuan a kilogram, the sales volume is limited and the promotion is not open. Li Jianyou concluded: "On the one hand, the breeding threshold is limited, the fish is small, more than 30 per kilogram, and the growth cycle takes two years; on the other hand, the popularity is not high, after all, it is only a matter of two years to become a new breed of aquaculture." ”
On the basis of the intensive breeding of the original flowing water pond, Li Jianyou figured out "raising indigenous fish in the rice field": set up water outlets and inlets in one side of the rice field, and dig a ditch on the side of the rice field. Through the control of rice field water volume, the water temperature can be adjusted, which affects the fish's eating habits and breeding period; when the rice is cut, the fish enter the ditch, overcoming the seasonality of rice field fish farming. As a result, production and revenue are rising steadily. Li Jianyou said: "This set of technology is simple and mature and easy to copy, and the scale of goldline catfish culture is no longer a problem. At the beginning of 2018, our farming area was 50 mu, producing 20 tons of commercial fish, and this year it is expected to reach 300 tons. ”
Li Jianyou's exploration coincides with Yang Junxing's idea of "three-dimensional wetland". "There are many streams in the small pit ponds and ponds in Yunnan with cold water, which are suitable for the growth of indigenous fish." Yang Junxing firmly believes that "the golden line catfish can produce benefits, and 'swimming' back to the people's table is a more reliable protection and an opportunity to promote the ecological governance of the lake basin." ”
Many people who have seen the former appearance of Dianchi Lake are full of expectations like Yang Junxing. Liu Hongkuan, an 85-year-old man in Baicao Village, recalled that when he was young, there were more fish in the water than leaves, and the golden thread catfish moved at night, and people stood in the ditch and hit their feet. "The gold thread catfish is as silky as a satin dress, and it is not afraid of people at all!" It sells more expensive than the average fish, and it is delicious. ”
From the old man's intoxicated expression, the reporter seemed to see the Dianchi Lake that was "full of joy and emptiness": there was "Apple Heaven and Reed Land", dotted with some green feathers and Danxia, fragrant rice and clear sand; where the smoke fell, you can see the fishing fire of the half river and the two rows of autumn geese. Up close, flocks of golden thread catfish pass between Longtan Creek and Dianchi Lake, shining in the sun, "the beginning and tail of gold are like a line"...
At that moment, the reporter's heart moved, thinking of Pan Xiaofu's words - "Protecting the Dianchi Lake golden thread catfish is also protecting our nostalgia."
Typography: Zhang Fangman