"Fish swim freely, birds fly freely." This is a beautiful dream of Hunan's green development. In order to make the dream come true, the provincial party committee and the provincial government proposed -
Open up the "life channel" of fish migration
On July 10, the Fish Road of Tugutang Power Station in Hengyang, Xiangjiang River, has been put into trial operation. Photo by reporter Tang Jun
On July 10, Hengdong County, Yangtang Water Wheel Pumping Station Yangtang Fish Road, which has been out of service since 1985. Photo by reporter Tang Jun
Xiangjiang Avionics Hub Fish Road. (File photo) Correspondent photo
Reporter Zhang Shangwu Correspondent Wu Shenshu
On June 26 this year, at the plenary meeting of the Xiangjiang River Protection and Governance Committee, Du Jiahao, secretary of the Provincial Party Committee and director of the Standing Committee of the Provincial People's Congress, proposed that it is a beautiful dream of Hunan's green development to swim freely and birds to swim freely.
In order to make the dream come true, the meeting proposed: Xiang, Zi, Yuan, Lisishui and Dongting Lake, to open up the "life channel" of fish migration, first find a way to open up the fish road of the Xiang River.
Over the past few days, the Provincial Bureau of Animal Husbandry and Fisheries has organized experts to repeatedly study the plan for opening up the fish road in the Xiangjiang River. Yuan Yanwen, director of the Provincial Bureau of Animal Husbandry and Fisheries, said frankly: "I really did not expect that the main leaders of the provincial party committee would attach so much importance to yudao. The relevant departments should go all out to achieve a smooth swim for the fish. ”
"I'm so happy for the fish." Liao Fuchu, chief engineer of the Provincial Institute of Water Science, who has been dealing with fish for decades, said happily: "In the past, the province mentioned the 'migration channel and ecological corridor', and now mentions the height of the 'life channel', it seems that the fish have really been saved!"
Many species of fish are endangered, and the "cradle of the four major fish" is worrying
Since the beginning of summer, the Xiangjiang River Basin has received abundant precipitation, and hydropower dams have opened their gates to discharge floodwater. According to common sense, the production of natural fry in the Xiangjiang River is expected to usher in a good harvest.
On Moon Island in Wangcheng District, Changsha City, the Provincial Institute of Water Science has a seedling fishing base here. According to the staff, since June, although the dams of power stations at all levels have been opened to discharge floodwater, the catch of natural fish fry in the Xiangjiang River is not much.
As the "cradle of the four major fish", the production of natural fry in the Xiangjiang River has been greatly reduced.
The Section of the Xiang River from Baifang to Songbai River in Changning is known as "Big Fish Bay". Standing on a high place, the river here turns with the shore, the water surface is wide, showing a Tai Chi pattern, and it is just like the tank of the artificial fish fry hatching pond, which is one of the three natural spawning grounds of the four major fish in China, namely green, grass, silver carp and bighead carp.
Turning through the "Big Fish Bay", the XiangJiang River flows from south to north through Hengyang, Zhuzhou, Xiangtan and Changsha, to Xiangyin County, Yueyang City, into Dongting Lake, and then to the river to the sea. In the past, migratory fish such as four large fish would swim along this waterway in the spring to the "Big Fish Bay" in Changning to spawn.
"Changning lays eggs, and looks to the city to fish for seedlings." Wu Yuan'an, director of the Provincial Institute of Water Science, introduced that the migration channel of the four major fish is about 300 kilometers, which is the waterway distance from Changning to Wangcheng. The fertilized eggs laid by broodstock in Changning float with the water to the Wangcheng River section of Changsha and will naturally develop into fry.
All along, the Provincial Institute of Water Science has set up a point in the Moon Island section of the Xiangjiang River, fished wild fry with hanging rows, transported them to the provincial fish seed farm, screened and cultivated the original fish species parents of the Xiangjiang River, and supplied the fry breeding farms in the province and the whole country to ensure the purity of the fry germplasm. Therefore, as the "cradle of the four major fish", the Xiangjiang River has always been well-known throughout the country.
In recent years, the production of natural fry in the Xiangjiang River has been in serious decline. Fishermen in Xitang Village near Moon Island reported that in the past, 1 million fry could be fished in one night, but now it is difficult to catch 10,000 fish.
According to the data provided by the Provincial Water Department, in the 1970s, there were more than 2 billion fish fry resources in the Four Major Fish Fry resources in the Xiangjiang River, and now it has plummeted to less than 100 million. As the "cradle of the four major fish", the Xiangjiang River has a worrying future.
Many species of fish are on the verge of extinction, exacerbating aquatic imbalances. According to monitoring, 90% of the catches in the Xiangjiang River in recent years are lake-dwelling fish and short-distance migratory spawning fish, and only about 10% of the drifting eggfish such as four large fish, and the proportion of wild populations has dropped to 6%.
Among the fish in the XiangJiang River, white sturgeon, anchovy, dark-striped oriental carp, Japanese eel, anchovy, manta rays, long loach, etc. have not been monitored for nearly 10 years, or have been functionally extinct; Long-jawed carp, Iwahara carp, cochineal fish, Chinese barbed catfish, white turtle, Xianghua carp, etc. have reached the "critically endangered" and "endangered" levels; Migratory fish resources in rivers such as bluefish, grass carp, silver carp, bighead carp, and carp have been in serious decline.
Landscape is nostalgic. As the mother river of Hunan people, the Xiangjiang River would be unimaginable if there were no fish in the river. Wu Yuan'an said: "Only when there are fish in the water is called a river." ”
The decline of fish stocks and the obstruction of the "way home" are the main reasons
"The fish in the river are getting smaller and smaller, and there are fewer and fewer species." In recent years, fishermen in the Xiangjiang Basin have increasingly found it difficult to make a living by fishing.
According to expert analysis, the reasons for the decline of fish resources in the Xiangjiang River include the interception of rivers by hydraulic buildings, water pollution, overfishing, quarrying and sand dredging, and biological invasion.
"Among these reasons, hydroelectric dams intercepting rivers are undoubtedly the primary reason for the sharp decline in fish stocks." Liao Fuchu, chief engineer of the Provincial Institute of Water Science, said that migratory fish have their own routes for wintering, spawning and feeding. Dams intercept rivers, fish migration channels are blocked, can not climb the dam to spawning farms, the river will be less and less fish.
At present, a 9-level dam has been built in the main stream of the Xiang River. In the "Big Fish Bay" spawning site below the Dayuandu, Tugutang, Kongtanzhou, Caijiazhou and other 4-level dams, layer by layer block broodstock swimming upstream, spawning grounds do not have broodstock to spawn, "cradle of the four big fish" fish resources are increasingly depleted.
In the spring, during the spawning and breeding season, groups of fish gather under power dams such as Tugutang, mainly broodstock of carp, carp and four large fish. In order to spawn, these migratory fish have gone through arduous efforts to find a "way home", and have been hindered under the dam and waited for the gates to open.
One dam after another has become a "dragon gate" that is insurmountable for fish. Even if there are broodstock spawning in upstream waters, drifting fish eggs need hundreds of kilometers of artesian channels, which can only naturally grow under certain flow rate and water temperature conditions. The dam causes the river to "pondize", and the drifting fish eggs are easy to sink into the bottom of the water and die, and the fish population is greatly reduced.
"In the 1970s, there were still more anchovies in the Xiangjiang River." In Liao Fuchu's memory, the Spring River plumbing, Changsha's vegetable market often has anchovy sold, the price is not expensive.
Speaking of anchovies, Liao Fuchu was very excited. This migratory fish, every year in the fourth and fifth months of the lunar calendar from the ocean into the Mouth of the Yangtze River, back up the river to the Xiang River to lay eggs, should come from time to time, punctual like a migratory bird, so called "anchovy".
Anchovies, puffer fish and knife fish are called "Three Fresh Yangtze River", and anchovies cherish the scales on their bodies. It is said that once a fisherman touches its scales, he will not struggle, because he is afraid that he will throw off the scales on his body. Due to the barrier of the hydraulic dam, the anchovies in the Xiang River have disappeared in the past 10 years.
Another fish that was once common in the XiangJiang River is called "white eel" (scientific name eel), and there were still many markets in Changsha in the 1990s. Liao Fuchu was well aware of the habits of white eels: this migratory fish, adults breed in the deep pacific ocean, and the juveniles follow the route taken by their parents to return home, along the Yangtze River across Dongting Lake, to the Xiang River to grow. In the past 10 years, no wild white eels have been monitored in the Xiangjiang River.
"Hydroelectric dams intercept rivers, fish migration routes are cut off, spawning grounds are submerged, and bait claims are destroyed." Liao Fuchu said with deep anxiety that the fish had lost their homeland and faced the disaster of extinction.
Fish thrive, "up" and "down"
The 9-level dams that lie across the Xiang River are mostly low-head dams. Relatively speaking, it is relatively easy to build fish facilities in low-head dams.
In the 1980s, the xiangjiang river tributary water flowed through hengdong territory, and a fish road was built at the Yangtang water wheel pumping station, which was the first fish road in our province. Recommended by the Food and Agriculture Organization of the United Nations, yangtang fish road was once a model for the fish road of low-head dams in the world.
On July 11, the reporter saw in the Yangtang Fish Road that after years of silt and silt, the gates had long been abandoned. Yangtang Fish Road once had as many as 320,000 fish per day, and the United Nations Agricultural Organization sent experts to investigate and promote it many times. Liao Fuchu believes that the fish road is basically complete, the silt is cleaned up, the new gate is built, and the Yangtang fish road is expected to restore the "ecological business card".
At present, there are two newly built fish channels in the main stream dam of the Xiangjiang River, namely the fish road of Tugutang Power Station and the fish road of the Xiangjiang Avionics Hub, which have been put into trial operation.
At the Fish Road of Tugutang Power Station, Liao Fuchu explained to reporters on the spot that the fish inlet is connected to the Huanshui Bay of the tail water of the power station, which is the place where fish like to gather; The gate opens and closes according to the downstream water depth, forming 3 fish inlets with different elevations; Measures such as electric grids, sound waves, temperature control, and light are used to lure fish into the fish channel.
Standing on the dam, the fish path has 4 slots side by side, like two paper clips. Xie Changqing, head of the Tugutang Avionics Hub, introduced that the width of the fish road is 0.53 meters, and the water depth is more than 2.5 meters, which meets the passage of four large fish broodstock; The flow rate of the fish channel is 0.5 meters per second, which is the most comfortable flow rate for fish to swim; When the fish are tired of swimming, they can also rest in the rest pool.
The fish road built for tens of millions of yuan ultimately depends on whether the fish "buy it". Therefore, the design team always finds ways to "fish" the fishway facilities as much as possible. Liao Fuchu introduced that the migratory fish of the Xiangjiang River mainly include four large fish, bream, silver bream, tuantou bream, triangular bream, bream, yellowtail bream, warped bream, Mongolian bream, southern bream and so on. Different fish have different spawning periods, and fish passages at all levels must be precisely regulated to have a good fish effect.
Two years later, with the completion of the fish road of Zhuzhou and Dayuandu, two major avionics hubs, the Xiangjiang Fish Road can reach the "Big Fish Bay" in Changning. Wu Yuan'an, director of the Provincial Institute of Water Science, said that even if the fish road is open, it is still unknown whether the "cradle of the four major fish" can be restored.
First, these dams have not yet implemented joint ecological dispatch. Every year during the fish breeding season, all dams should open fish lanes and do a good job of protecting fish. No matter which level of fish is not passable, the broodstock cannot reach the "Big Fish Bay".
Second, the fish path only solves the problem of migratory fish "going up". Broodstock swim back to the "Big Fish Bay" to spawn, and the fertilized fish eggs have to be "down". Dams at all levels should uniformly coordinate the discharge flow to create artificial habitats for natural reproduction of floating fish eggs. Otherwise, the fish eggs in the dam will sink to the bottom and die, and the fish in the river will not increase.
If yudao is "hardware", ecological joint scheduling is "software". Wu Yuan'an said: "Only when 'soft and hard are applied', the fish in the Xiang River will flourish and flourish, and the Mother River can live endlessly." ”
■ The Stone of His Mountain
Famous fish trails at home and abroad
Qinghai Lake: Huangyu Migrating "Landscape Fish Road"
The unique Huangyu of Qinghai Lake migrate to the tributaries from March to July every year, and spawn in an environment with clear water quality and slow and stable flow rate. Since September 2015, the local government has invested nearly 37 million yuan to build seven migratory fish migration channels on the Shaliu River, Quanji River and Hargai River. These passages are stepped, with a step about 30 cm high and a small pool between each staircase. After swimming up the lower steps, the huangyu can "recharge" in the small pool and continue to swim upstream. The humanized rest area can not only alleviate the pain of the journey of the huangyu, but also serve as an ornamental area for people to enjoy the wonders of the huangyu swimming upstream and spawning, which has touched countless tourists and aroused people's awareness of ecological protection.
Guangxi: Changzhou has a "caring fish road"
Guangxi Changzhou Water Conservancy Hub is a large-scale project on the Xijiang River, supporting the construction of fish roads, including the inlet section, fish channel pool, lounge, flood gate section and exit section, with a total length of 1444.3 meters. In order to let the fish take this passage, the engineering designers tried their best: such as carefully designing the ramp to slow down the flow rate of the water; Underwater installation of pulse equipment to create "artificial waves"... These measures led to an increase in project costs of more than 100 million yuan, and finally allowed the dominant fish such as red-eyed eel, Japanese eel, loach, and silver floating fish to enjoy "intimate care".
USA: Creating a "Genius Fish Path" for Eels
The St. Lawrence River is one of the largest rivers in North America. The St. Lawrence Hydropower Station jointly built by the United States and Canada blocked the migration of American eels from the western Pacific Ocean to Lake Ontario, and the United States decided to build an eel crossing facility at the St. Lawrence Hydropower Station. This fish tunnel, specially built for eels, consists of fish ladders, collection buckets, pipes, receiving boxes and other components; Fish ladders transport eels from under the dam to the dam; After collecting buckets, using the water-top habit of eels, enter the pipeline; Insulation of pipes to avoid high temperatures during the day; The eels take the pipeline into the receiving box about 300 meters upstream of the dam and safely release it into the river, and the eel pass rate is about 85%. Years of research and careful design have earned this fish course the reputation of "genius fish road".
Japan: Fish and shrimp protection gives birth to the "Paddy Fish Road"
Japan originally set up fish channels to focus on the protection of fish stocks such as ayu, salmon, and trout, which need to travel between the upper and lower reaches of rivers and between the sea. In recent years, from the perspective of protecting ecosystems, the protection of fish and shrimp in waterways separated during the preparation of farmland and paddy fields has also been considered as a consideration for the construction of fish channels. There are also some fish that originally live in rivers and waterways, but during the flood season, they will breed in places such as flooded rivers, reed fields, and irrigated farmland. Against this background, the "Mizuta Fish Road" was born, where waterways and paddy fields are connected.
■ Reporter's Note
Fish-water harmony will sometimes
Zhang Shangwu
The Xiangjiang River Conservation and Governance Committee recently decided that the Xiangjiang Mainwater Power Station should implement the responsibility for the construction of fish channels and open up a "life channel" for fish migration. This news can be called the "gospel" of the fish under the dam.
Since the 1970s, nine hydroelectric dams have been built on the main stream of the Xiang River. The tall dam, without fish facilities, has become a "dragon gate" that is difficult for fish to jump over. Year after year, in Tugutang and Dayuandu power stations, every fish spawning season, migratory fish swim upstream, a large number of gathering under the dam, and the "life channel" such as bitterness is opened.
The high dam not only blocks the migration channel of fish, but also changes the water flow, water depth and water temperature, which greatly affects the habitat and reproduction of fish. In the past 30 years, 17 species of fish have disappeared in the Xiangjiang River, and the production of natural fry of four major fish, such as green, grass, silver carp and bighead carp, has decreased year by year.
The river channel is fragmented, some fish are extinct, and the entire ecological chain is inevitably damaged. Over the years, aquatic biology experts in the province have called for: the Xiangjiang River water is clear and the fish leaps, and the virtuous circle of fish and water harmony is reconstructed.
To reconstruct the harmony of fish and water, we must first open up the fish migration channel. The provincial party committee and the provincial government made a decisive decision to supervise the implementation of the responsibility for the construction of fish channels in the main stream of the Xiangjiang River, and all the hydropower stations below the Changning section of the Xiangjiang River were newly built or supplemented, so that migratory fish could swim unimpeded and smoothly "go home" to spawn.
Reconstruct the harmony of fish and water, and strive to restore the "cradle of the four major fish". The provincial government has formulated a preliminary plan to implement joint ecological scheduling for the cascade hub of the main stream of the Xiangjiang River, and to create an artificial habitat for natural fish reproduction under the unified coordination of the fish breeding season, and to reproduce the grand situation of "changning spawning and wangcheng fishing for seedlings".
Reconstruct the harmony of fish and water, but also let the fish "live comfortably". For many years, the fishery administration department in the province has adopted breeding and stocking to restore the number of fish stocks; Implement the spring fishing ban system to protect fish resources and let the "Mother River" live forever.