What are the living habits of Yangtze river swordfish?

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Yangtze swordfish

Release date: February 6, 2006 at 9: 03: 04

Yangtze river swordfish, scientific name is silver carp with long jaws, also known as silver carp. Its body is long and flat, its abdomen is silvery white and rich in fat, so it is named after it looks like a sharp knife. Distributed in the Yangtze River and coastal semi-salty fresh water areas. In the breeding season, it enters fresh water from the estuary, returns to the farms in the middle reaches of the Yangtze River for breeding and migration, and reaches Dongting Lake as far as possible. Some of them lay eggs in the main stream of rivers, while others enter tributaries and Tongjiang lakes. After spawning, the parent fish feed in fresh water and gradually return downstream to the estuary and offshore to continue fattening. The larvae of bonito also migrate to the estuary to fatten up. In winter, bonito will not migrate long distances, but gather in the deep offshore for the winter. It is a typical migratory fish.

The problem of sky-high price of Yangtze river swordfish: behind the sky-high price of 10 thousand yuan is a painful ecological price

This kind of fish is long and flat, with a silver belly and rich fat, so it is named because it looks like a sharp knife.

Yangtze river swordfish, scientific name is silver carp with long jaws, also known as silver carp. Relatively speaking, people are more familiar with another fish belonging to it-anchovy, which is the common name of Coilia ectenes. Like Coilia ectenes, two species of fish, as close relatives, usually inhabit the shallow sea near the estuary in eastern China, and spawn upstream every spring and summer, which is a typical migratory species.

Residents of many cities along the Yangtze River call the Yangtze River saury a river knife. They know that compared with the anchovies fried in tin cans and sold for six or seven yuan a box, the value of river knives can't be mentioned in the same breath-in a hotel in Jiangyin, three river knives are put together into a catty and steamed into a plate, and the price is 10 thousand yuan, which is the latest sky-high price this year.

Some older Jiangsu people also know that this huge price difference was formed in the previous 20 years. Once upon a time, people in cities along the Yangtze River could taste fresh food several times in Tomb-Sweeping Day, just like the full moon in the Mid-Autumn Festival, enjoying chrysanthemums and eating hairy crabs.

"Looking at the net and painting a silver knife" is a sentence of Su Shi in the Song Dynasty, and Li Yu in the Qing Dynasty called it "a wonderful thing in spring". According to historical data, the catch of Coilia ectenes once accounted for 35%~50% of the natural catch of fish in the Yangtze River, and the proportion in Jiangsu was as high as 70%. Nowadays, the Jiangnan custom of ordinary people eating river knives in spring has become a luxury. In 2005, a Shanghai media wrote in an article: "Have you ever eaten Yangtze saury? If you ask young people this question now, I'm afraid you'll have to change it to: Have you seen saury? " On may 1 day, the swordfish fishing license in the hands of fishermen along the river expired, and this year's swordfish season officially ended.

Up to now, there is no exact statistical data on the total catch of saury in the Yangtze River in 2005, but the market situation has proved that this figure is a foregone conclusion compared with last year. According to a data from the Freshwater Fisheries Research Center of Chinese Academy of Fishery Sciences, the output of river knives along the Yangtze River was 3,750 tons in 1973 and about 370 tons in 1983. In 2002, the output was less than100t.

"This is not a linear decline, but a geometric series decline, which proves that our utilization of Coilia ectenes resources has reached its limit." Shi Weigang, director of the Resource Research Office of the Freshwater Fisheries Research Center, said.

Within two weeks, the reporter visited several cities in the lower reaches of the Yangtze River and found that the expensive Yangtze saury was a loss rather than a gain for fishermen and operators. In the eyes of scholars trying to save the saury population, it is the whole Yangtze River ecology that really pays a painful price.

Swordfish season of fisherman Chen Chusheng

Chen Chusheng also admitted that during the swordfish flood season, he and his younger brother only caught more than 300 kilograms of swordfish, which was only equivalent to the catch of a net in the 1980s.

At 7: 54 am on April 26, a 30-cm-long river knife was pulled out of the river, and the fish shining in the sun quickly slapped the water. Immediately, the fish stuck on the net hung up. It twisted its head to the river desperately, twitched left and right, and bent into a stiff semicircle again and again.

This is the first Yangtze saury caught by Changshu fisherman Chen Chusheng that day. Two hours ago, he and his younger brother Chen Chugen each drove a diesel-powered fishing boat, starting from Hupu Fishing Port in Changshu and heading east into the Yangtze River near Sutong Bridge. This is 62-year-old Chen Chusheng's favorite fishing ground in Dao Jiang.

At 7: 0010, Chen Chusheng's wife Liu Fengying and her youngest son Chen Liang threw a gill net into the river between two ships.

Five or six minutes later, a 500-meter-long net was dragged by two ships and slowly unfolded in an arc along the river. The river here is shallow and fast, and it has always been a river knife fish path. The gill net with a grid of 3 cm square extends to the bottom of the river, which can just intercept the fish.

This morning, after dragging the net twice, the Chen Chusheng brothers got the biggest catch of their swordfish season: 30 Jin of Dajiangdao *** 159 treaty.

But Chen Chusheng himself was not as excited as the reporters who witnessed this process, and the harvest came too late. At this moment, it is the season when the river knife falls into the market, and the purchase price given by the fishmonger is less than one tenth of the peak period.

More than a month ago, fishermen on the Yangtze River would see fishmongers flying by in speedboats. The latter searched every fishing boat that caught the river knife and offered a high price of 1 kg 700 yuan to 1 10,000 yuan. At that time, the river knife had a sky-high price of 1 kg of 2000 yuan.

But at that time, Chen Chusheng could only wave at the traffickers.

On March 15, the old man who has been catching swordfish all his life cast the first net of the swordfish season in 2005. The unprecedented high price in the market made him feel that he was facing a gamble with the highest stakes. "My hands were shaking when I slowed down the throttle of the boat," Chen Yusheng said.

On that day, when the 500-meter-long gill net was slowly pulled out of the river, Chen Chusheng saw the first empty net in his career. On that day, he cast four nets, all of which were empty, and the swordfish disappeared without a trace. After eight days, nothing was found. On the ninth day, the first river knife in 2005 appeared on his gill net, but the harvest of that whole day was only 2 Jin 82 Liang.

"This is something that has never happened in any year. My feeling is that this year's river knives are at least half less than last year. " On April 26th, Chen Chusheng was still worried about the unfavorable start of this year's swordfish season. He lowered his head expressionless and unconsciously paddled the boat with his right index finger. Son cat stopped at this time. "My dad has been fishing for decades, and I have never met an empty net before this year. Can you imagine his mood? What kind of mood will it be for a farmer to plant land for a year and finally get nothing? " In fact, when the reporter informed a staff member of Changshu Fishery Station of Chen Yusheng's harvest on April 26th afterwards, the other party couldn't believe it. "There will be so many?

The most fish this year is in recent days, but it is a good harvest to catch 10 A Jin Day. The fisherman was surprised for a reason. This spring, many city media in Shanghai, Jiangsu and Anhui exclaimed that saury was "missing". Shanghai Wen Wei Po April 1 It is reported that Li Jingui, a fisherman in Nantong, has only caught five swordfish in the dozens of days since early February.

Chen Yusheng also admitted that the harvest on April 26th was his rare luck this year. During the whole swordfish flood season, he and his younger brother only caught more than 300 kilograms of swordfish, which was only equivalent to the net catch in the 1980s.

In the old fisherman's mind, there is a clear output table of river knives: "Before 1973, we were also two boats fishing for river knives, but the boat was a rowing boat. The net is only one-third as long as it is now, and the quality is not good. If you catch a fish, you have to mend it once. However, before and after Tomb-Sweeping Day, a net can catch at least 200 kilograms of river knives and at most 600 kilograms.

"1973, Jiang Dao is the most. A master in our village grabbed 10000 Jin of Jiang Dao one month before and after Tomb-Sweeping Day. I caught 6000 Jin that year. The biggest river knife I have ever caught weighs six times. At that time, the river knives were even, and four fish a catty was enough. " "After 1973, Jiangdao became thinner every year. After 1995, the number dropped the fastest, but in that year, there were still forty or fifty kilograms in a net, and 1997 was only twenty or thirty kilograms in a net. " "Before and after Tomb-Sweeping Day in 2002, there were only one and two. That year, the price of river knives soared, and the purchase price of fishing boats was 1 kg 500 yuan. In 2003 and 2004, the number of river knives did not drop significantly, but the purchase price of fishing boats rose to 650 pieces per catty before and after Qingming. "

The origin of the sky-high river knife

Yupo Farmers' Market in Xingang Town, Jingjiang City, Jiangsu Province was an important source of high-priced river knives in 2005 two months ago. There have been many incidents of "robbing fish" in the market, and some people even fought.

On the morning of April 29th, swordfish was still sold in every aquatic product shop in Yupo Farmers' Market, Xingang Town, Jingjiang City, Jiangsu Province, dozens of kilometers away from Chen Chusheng fishing boats. At this time, the price of more than 2 swordfish is more than 0/00 yuan per catty/kloc.

This seemingly calm largest farmer's market in Jingjiang City was an important source of high-priced river knives in 2005 two months ago.

"At the end of February and the beginning of March, my rice was sold at 1800 and 1700 per catty. This good market lasted for a week, which was higher than last year by 300 yuan. " A stall owner surnamed Liu fiddled with the ice on the swordfish with his hand and recalled with some excitement.

During that time, many limousines stopped at the market gate every day. Car owners in Shanghai and Nanjing want to buy authentic Yangtze saury, but many of them will be "persuaded away" because Yangtze saury is seriously out of stock and it is difficult to buy it at a high price. Buying fish depends on "relationship"

That's when fisherman Chen Chusheng was worried about the empty net. Obviously, there is a direct causal relationship between the market in Dao Jiang and the fishing boats on the river.

The reason why wealthy customers gather in the fisherman's farmer's market to buy "authentic" river knives is also related to the migratory habits of Yangtze river swordfish. Jingjiang has been known as the "hometown of swordfish" since ancient times. It is said that the farthest point where the tide flows into the Yangtze River estuary is Jingjiang New Port, which has been the place where river knives gather in groups since ancient times. Moreover, when they migrated here, the salt content of the fish was gradually diluted appropriately, and the gonads began to develop rapidly, so the river knives produced here were the most delicious.

According to local market sources, the number of river knives produced by Jingjiang Xingang this year is actually very small. River knives are mostly collected from Shanghai and other river sections in Jiangsu, and Jingjiang swordfish is the highest. What's more, the sea knives caught in Shanghai and the lake knives caught in Chaohu Lake, Anhui Province are all "gilded" in the local river water, posing as river knives.

As the name implies, sea knife refers to swordfish that has not migrated offshore, while lake knife is similar to river knife that has lived in fresh water for a long time. Real diners know that although the sea knife and the lake knife are similar in shape to the river knife, they are not the same in taste and value.

Another stall owner told reporters that when Jiangdao was first listed this year, there were many incidents of "grabbing fish" in the market, and some even fought. At one time, some aquatic products shops auctioned river knives. It has been confirmed that the most expensive river knife is more than 2000 yuan.

This spring, the unprecedented price in Dao Jiang has become a common phenomenon along the Yangtze River. Many local media reported this: On March 5th, the retail price of Nanjing Dao Jiang went against the normal trend of gradual decline after listing in previous years, and the price of 150g (3 liang) rose from 2,400 yuan/kg at the beginning of listing to 3,000 yuan/kg, setting a new high in the past four or five years.

In March, the Suzhou market shouted out the sky-high price of 4000 yuan for a kilogram of river knives.

In March, the river knives in Shanghai market exceeded 4000 yuan per kilogram.

On April 12, "Yangtze saury" was fully listed in Tongling market, Anhui Province, with an asking price of 3,600 yuan per kilogram. Although this Jiang Dao is suspected by experts to be an old frozen product the next year.

"Fish bones are as soft as cotton before Qingming and as hard as iron after Qingming", and the appetite of diners is also an important determinant of Jiangdao market.

Dao Jiang, shad and puffer fish have been called "Three Fresh Species of the Yangtze River" since ancient times. Because swordfish is the earliest listed, it ranks first in the three fresh foods. However, this kind of fish has many fine spines, so the change of fish bone hardness before and after Qingming largely affects its taste.

A Nanjing diner who loves to eat river knives described: "The river knives in front of Tomb-Sweeping Day are tender and delicious, and the fishbones melt in the mouth. That feeling makes people just want to close their eyes and be intoxicated. " Li Yu, a gourmet in Qing Dynasty, also wrote: "When eating crucian carp and sturgeon is annoying, the more you chew, the sweeter it becomes, and you can't get rid of it." In recent years, the river knife in front of Tomb-Sweeping Day has become one of the most fashionable gifts in the cities of the Yangtze River Delta, but the dish of steamed swordfish in the restaurant can best reflect its value.

Jiangyin City, separated from Jingjiang City by a river, ranks among the top 100 counties and cities in China in terms of economic strength. The staff of a Jiangxian Museum here revealed that before the Qingming Festival, the price of a river-steaming knife in the museum was as high as 6,000 yuan. He said that a plate usually contains three river knives, weighing about 1 kg.

According to the data, Tomb-Sweeping Day Qianjiang fish contains fat 16.8g, protein 14g and phosphorus1.1g. The beauty of the steamed river knife is that it does not scale when put into the plate. At high temperature, the fine scales of the fish body become oil droplets, which are more delicious.

According to an insider, in Jiangyin this spring, the price of each steamed river knife in a high-end hotel exceeded 10,000 yuan.

Not only that, the owner of a Jiangxian restaurant in Jiangyin said that before Tomb-Sweeping Day, he would worry about the source of the river knife every day, because the competition between hotels was concentrated on this kind of fish: "Which restaurant has authentic river knife today, which business is good, because it means that rich diners will come." Media reports show that similar competition once appeared in Shanghai, Nanjing, Suzhou, Wuxi, Changzhou, Nantong and other places.

The fishing cost of a fish.

Chen Chusheng and Chen Chugen caught more than 300 kilograms of swordfish and sold it for more than 20,000 yuan, but the diesel oil consumed by the two ships amounted to more than 4,000 yuan. In this way, each family can only get about 8000 yuan.

And this 8,000 yuan will be the whole life of the Chen Chusheng family for half a year.

At noon on April 26th, on the deck of the fishing boat Su Changyu 19037, Chen Chusheng pointed to three piles of river knives and estimated his daily income.

2 More than two pieces of 56 river knives, accounting for 14 Jin 2 Liang, 60 yuan per Jin; Zhongjiang Dao 65 1 half to 22 Liang, about 10 Jin, per Jin 15 yuan; 38 Xiaojiang knives under 1, about 4.5 kg, 5 yuan per kg.

The biggest swordfish fishing in 2005 brought the brothers in Chen Chusheng about 1000 yuan. In terms of the amount, the selling price of 30 Jin of fish is not as good as the 2 Jin 8 Liangjiang Dao he first harvested in late March. At that time, Dajiang Dao was sold in 700 yuan for more than 400 yuan per catty/kloc-0.

This spring, more than 300 kilograms of swordfish caught by Chen Chusheng and Chen Chugen sold for more than 20,000 yuan, but the value of diesel oil consumed by the two ships reached more than 4,000 yuan.

In this way, each family can only get about 8000 yuan. And this 8,000 yuan will be the whole life of the Chen Chusheng family for half a year. Six months later, their brother will sail to the river again to catch Coilia ectenes.

Now, another problem facing Chen Chusheng is that the cost of boats and nets cannot be recovered.

"I regret buying this net." Chen pointed to the spunlace net made of white chemical fiber and said that it was the most expensive fishing net he had ever bought, worth 6,000 yuan.

For an old fisherman like him, it is as natural and necessary to have this special swordfish net as a soldier wants to have a good gun. Four years ago, in order to marry Chen Liang, a 30-year-old son, 59-year-old Chen Chusheng decided to try again, so he spent 40,000 yuan to buy a second-hand small steel and firewood fishing boat, and at the same time gritted his teeth and bought this expensive gill net.

"I have been catching Dao Jiang all my life, and I know that Dao Jiang is getting less and less every year, but I never expected that the output of Dao Jiang would drop so quickly." Four years ago, when Chen Chusheng bought a boat net, the income of a river knife season was at least twice as much as it is now.

This time, he heard another bad news from the reporter. Since the Yangtze River was closed to fishing in spring in 2002, thousands of river knife fishing licenses have been favored by fishermen in the first two years. However, quite a lot of fish are still in the hands of fishery officials this year. Take Changshu as an example, only 14 of 29 cards were issued.

Chen Liang, the youngest son who went fishing together, intended to follow in his father's footsteps, but now he has changed his mind: the number of river knives is running out, and the number of anchovies is decreasing year by year. The fishing industry is unprofitable, so we must seize the time to "enter the factory".

"No one in the village attaches importance to fishing, and fishing will starve to death." Chen Liang answered the reporter like this. He waved and pointed to the factories on the banks of the river and the dredging boats in the river.

It's not just Jiang Dao who is missing.

The Yangtze River shad, listed as "Three Seasons of the Yangtze River", has been missing in the Yangtze River for five or six years. Its process is also a sharp decline in the number in the past decade, the migration route is shortened, and then it disappears completely.

In Changshu Fishery Station, which is in charge of managing fishing boats in Chen Chusheng, Zhang Jinhua, the deputy stationmaster, disclosed the same disturbing figures: 1973, Suzhou River produced about 400 tons of river knives, and Changshu alone produced 70 tons, while in 2004 Changshu produced only about 2 tons of river knives.

However, Shi Weigang, director of the Resource Research Office of the Freshwater Fisheries Research Center of the Chinese Academy of Fishery Sciences, the authoritative research institution of Yangtze River swordfish, has been unable to provide reporters with the overall annual output data of swordfish after 2002: "As far as I know, there is no authoritative statistics, because the number is too small, it is difficult to count." In Shi Weigang's eyes, river knives are beautiful, like handfuls of silvery white knives. Every year from the end of February to the beginning of March, he enters the Yangtze River from the East China Sea, draws his sword and cuts off the water, and goes upstream. Its speed is so fast that it can cross thousands of kilometers in ten days and reach Dongting Lake in Hunan as far as possible. "The river tour is like a knight with superb swordsmanship, performing the most magical swordsmanship in the clear sky." A large number of historical data prove that Coilia ectenes originated from the Yangtze River estuary to Dongting Lake in Hunan Province since ancient times. More authoritative data show that in history, the fishing yield of Coilia ectenes once accounted for 35% to 50% of the natural catch of fish in the Yangtze River, and the proportion in Jiangsu Province was as high as 70%. "This state of affairs lasted until the 1970s." Shi Weigang said.

"However, in the late 1980s and early 1990s, there were basically no migratory swordfish in Hubei section of Hunan Province. Two or three years later, the Jiangxi section was gone. 1996 or so, the Anhui reach cannot be fished.

"Jiangsu section was not spared, 1997, 1998 or so. First, there is no fishing news in Nanjing. Later, the output of Zhenjiang and Yangzhou rivers also dropped sharply. Now the migration route of saury is greatly shortened, and it can form the upstream of the fishing moratorium, only to Changshu and Jiangyin in Jiangsu. " Shi Weigang said that the current situation of river knives always reminds him of another aquatic animal in the Yangtze River-Eriocheir sinensis (wild hairy crab). "This kind of crab is also a migratory animal. 1992 is still in Wuxue reach of Hubei Province. In just 10 years, only the Shanghai section is left, with an annual output of only one or two tons. " "Jiang Dao may not be as lucky as this crab, because the artificial reproduction of this crab has been successful. Even if it disappeared in the Yangtze River, its population did not disappear. However, the artificial propagation of river knife has not been successful. If we don't cherish it, we may not even be able to keep the population. " Shi Weigang raised his voice.

Another comparable fish is the Yangtze River shad, which has been missing in the Yangtze River for five or six years. Its process is also a sharp decline in the number in the past decade, the migration route is shortened, and then it disappears completely.

"Poor fish" came and never came back.

Qin believes that if Jiang Dao didn't have an amulet-"bone as iron" after the Qingming Festival, it would no longer be delicious and might have been extinct long ago.

"From the perspective of a fish, the migration of the river knife is very tragic. Think about it, spring is blooming, and the river knife is struggling to swim to the Yangtze River in order to fall in love, lay eggs and reproduce. But humans have spread thousands of nets on the river and captured them before they could breed! " Qin, an associate professor at Nanjing University, aged 7 1, said.

At the turn of 1970s and 1980s, Qin Ansheng, led by Professor Yuan Chuanmi from NTU College of Life Sciences, participated in the early research of river knives in China. "This kind of fish has a bad temper. After being caught, it is not as quiet as other fish, but it is unwilling to struggle hard. It consumed a lot of oxygen and died a few minutes later. We still don't know whether the poor fish died of lack of oxygen or shock. In short, it is a dead end. " Fisherman Chen Yusheng also told reporters that in addition to regular fishing boats, there are many illegal nets in the river, such as small trawls, deep-water nets and inserting nets. Some nets are so small that they will kill aquatic fish and even catch fish eggs.

Qin believes that if Jiang Dao didn't have an amulet-"bone as iron" after the Qingming Festival, it would no longer be delicious and might have been extinct long ago. This is an open hand left by nature for Jiang Dao. At this time, Jiang Dao has the opportunity to swim to the spawning ground to complete reproduction.

However, when the river knife egg becomes a fry, the road back to the sea is extremely difficult. Another scholar specifically mentioned the eel fry craze of 1989. At that time, due to the soaring price of eel at home and abroad, artificial breeding of eel could make huge profits, but artificial breeding of eel could not solve it. For a time, nets and nets were everywhere in the lower reaches of the Yangtze River, and eel fry were caught wildly.

"The mesh of the eel seedling net is small enough to hang granular fish eggs with slightly larger particles. Because the fishing season of the eel seedlings partially coincides with the time when the river knife seedlings return to the sea, for a time, countless river knife seedlings were hung on the eel net and eventually thrown away as waste. "

The rhetorical question of grass-roots fishery officials

In the face of scholars' view that fishing for river knives should be banned, a grass-roots staff member of Changshu Fishery Station asked: "If you haven't caught light for thousands of years, you can catch light in these twenty or thirty years?" He believes that the main reason for the reduction of river knives is the water pollution in the Yangtze River.

"Now it seems that our appeal more than 20 years ago did not work. Today, Jiang Dao is still right by our crow's mouth. I am very sad because this is completely avoidable. " Qin said that in the late 1970s and early 1980s, five teachers from the Academy of Life Sciences studied river knives for five or six years. At that time, they felt that the number of river knives was decreasing year by year. Therefore, they have repeatedly called for limiting the capture of river knives at various domestic scholars' exchange meetings, and have already reflected it to the National Animal Association.

The reality is that the relevant state departments have noticed the problem of fish resources in the Yangtze River. In 2002, the Yangtze River began to ban fishing in spring, limiting the fishing of Coilia ectenes and anchovies in the Yangtze River.

During the river knife breeding season from April to May, the Ministry of Agriculture requires fishermen to hold a special license to catch Coilia ectenes.

But both Shi Weigang and Qin Anlu hold the same view: according to the current situation, the river guide should prohibit fishing, not restrict it. "In order to keep this population, the taste of river knives is beautiful and fresh, and human beings have to give up this delicacy temporarily." Shi Weigang's reason is that if human beings want to make sustainable use of river knives, they must find an "inflection point". "If there are 500 tons of river knives in the Yangtze River that are not fished, humans will catch 250 tons this year and will be able to recover to 500 tons through natural breeding next year, so 250 tons in the river is the turning point.

"Humans use resources above the turning point, which is sustainable utilization.

Using resources under the' turning point' is destructive use. Due to destructive utilization, this species will become extinct. This is a scientific law. "Stone said.

In the face of scholars' views, a grass-roots worker at Changshu Fishery Station asked: "You haven't caught light for thousands of years. Can you catch light in these twenty or thirty years?" He believes that the main reason for the reduction of river knives is the water pollution in the Yangtze River.

"How many economically developed cities can find fish in their own rivers? Why is the river knife going extinct? Ask the big taxpayers along the river. " The fishery official said.

Recently, the Municipal Committee of Population, Resources and Environment of China People's Political Consultative Conference and China Development Research Institute jointly organized an investigation team to protect the Yangtze River. Zhang Qi, executive director of China Development Research Institute, who participated in the survey, told the media afterwards that Chongqing is a small coking and mining enterprise, involving Hubei, Jiangxi, Anhui and Jiangsu, and there are many large-scale heavily polluting enterprises such as steel, shipbuilding and ship dismantling along the river. What's more, the sewage treatment devices of these enterprises are almost all "deaf ears", and a considerable part of the sewage is directly discharged into the Yangtze River without treatment.

According to the Annual Report of China's Environmental Statistics (2003), the total amount of wastewater discharged in the Yangtze River Basin in that year was163.9 billion tons, including 72.5 billion tons of industrial wastewater and 91400 million tons of domestic sewage.

Another position of Shi Weigang is the stationmaster of the fishery resources monitoring station in the lower reaches of the Yangtze River under the Ministry of Agriculture. For example, he said that in the spring of 1999, in Zhenjiang section of the Yangtze River, the original monitoring point of Coilia ectenes was affected by the sewage discharge of a nearby large enterprise, and there was no trace of Coilia ectenes. At this time, the output of Coilia ectenes in Nanjing and Jiangyin has been stable.

"Even if the concentration of pollutants will not kill Coilia ectenes temporarily, its long-term chronic toxicity will also affect the reproductive system of Coilia ectenes, leading to abnormal reproductive system and decreased fertility. In addition, the presence of pollutants in the water will also affect the richness of bait organisms in the water, which in turn will affect the fullness of Coilia ectenes and reduce its commercial value. " Shi Weigang said.

Fisherman Chen Chusheng also thinks that after 1973, the number of river knives began to decrease. "After that, factories were built on both sides of the river, and sewage and wastewater were discharged." His son Chen Liang added that he often saw carp, sturgeon and snapper choked to death by sewage near some big factories.

Chen Chusheng, who has been fishing all his life, has three meals a day on the boat, and the drinking water is also taken directly from the Yangtze River. His most direct feeling is that "the river used to be very sweet, but now it tastes bad."

Who will protect Jiang Dao's spawning ground?

So far, no place along the Yangtze River has started the investigation of Dao Jiang spawning grounds, no one knows where the new spawning grounds are, and no one knows whether these places are being destroyed by sand dredgers or various river projects.

The teachers of Shanghai Fisheries University have their own views on the main reason for the sharp decline in the number of river knives-the widespread destruction of the spawning grounds of river knives.

Qin told reporters that their investigation of Dao Jiang in the late 1970s made a big gain in finding out the characteristics of Dao Jiang's spawning grounds at that time. "At that time, the spawning grounds in Dao Jiang were mainly distributed in Anhui, Jiangxi and Hunan sections, generally lakes or inland river estuaries connected with the Yangtze River." For this information, what is the urgent voice that has been rushing around in Dao Jiang to study the front line in recent years: "Do you know that these primitive spawning grounds are basically destroyed now? In order to prevent floods or develop fisheries, local water conservancy projects have been built in those lakes and inlets, and the gates connected with the Yangtze River are only opened when people need them. Who will meet the spawning needs of Dao Jiang? " For example, he said that there is a rape lake in Anqing River section, which is a traditional spawning ground in Dao Jiang. Now, because the flood control is blocked, the migrating river channel can't swim in. "The key is that domestic water conservancy projects have not taken these into account in the past, and no fishways have been built." Qin's point of view is that there are river knives in the Yangtze River, so there must be a spawning ground in theory.

"But so far, there is no place on both sides of the Yangtze River to initiate an investigation on Dao Jiang's spawning grounds. No one knows where the new spawning grounds are, and no one knows whether these places are being destroyed by sand dredgers or various river projects. " What does this mean? "If these spawning grounds are not protected, further human activities are likely to be trapped in the Yangtze River saury."

If you are a fish.

"When human beings expand their living space, it is good to think more about fish and other animals. Otherwise, the day of punishment will always come. "

On the afternoon of April 27th, Tang Wenqiao, a professor of ichthyology at Shanghai Fisheries University, said with a smile, "You can look at the problem from another angle." "If you are saury, you will be angry with many human behaviors in the past 20 years. Think about it, you and your partner swim from the sea to the river, and you have a happy and free mood, because the Yangtze River is your home.

"You and your partner go upstream, and you like the feeling of water flow. But you find that the current in the river slows down, because many dams have been built in the upper reaches of the river. Then you find that the river water in some places tastes bad.

"You swim to find the place where you were born and give birth to your next generation. But a gate is blocking your way, or that tributary has a choking smell. You also found that many riverbanks are not made of soil, but of cement, and many of your favorite aquatic plants are gone.

"Far more than that, you are not happy to eat. You like shrimp and whitebait very little ... "Tang Wenqiao said after completing his hypothesis that this is not just a river knife, but all the fish living in the Yangtze River. "When human beings expand their living space, it is good to think more about fish and other animals. Otherwise, the day of punishment will always come. " Chen Chusheng on the fishing boat said to himself, "I wonder if I can see a river knife in the Yangtze River on my 70th birthday." My son Chen Liang said, "I haven't seen Yangtze shad for 10 years, and I have forgotten what it looks like." 10 years, will I forget what the river guide looks like? "

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