2019-11-12 06:53
Yangcheng Lake hairy crab is a relatively well-known variety on the market, but recently, in order to protect the water quality of Yangcheng Lake , Suzhou City has reduced the information on the breeding area of hairy crabs in Yangcheng Lake for many years, attracting the attention of many consumers.
Ecological pressure increases
0Crab breeding area in the lake has been reduced by nearly ten times
Yangcheng Lake Town is located on the northeast side of Suzhou urban area, on the shore of the beautiful Yangcheng Lake, which is famous for the abundant production of Yangcheng Lake hairy crabs.
The water area of Yangcheng Lake is about 180,000 mu. Hairy crab breeding emerged in the 1980s and 1990s. Fishermen who have fished by the lake have transformed into hairy crab breeding. By around 2000, the area of fences for breeding hairy crabs in Yangcheng Lake reached 150,000 mu. Many crab farmers call the densely packed fences at that time "mazen array". Because the fences are too dense, even old crab farmers often lose their direction when they shuttle between the fences on the lake.
Zhong Weidong, captain of the Yangcheng Lake Fisheries Administration Supervision Detachment of Suzhou City, said that in 2001, the entire Yangcheng Lake could be said to be a net of heaven and earth.
As the area of hairy crabs continues to increase, the degree of eutrophication of in Yangcheng Lake is also deepening. In order to prevent the water quality from deteriorating and the outbreak of cyanobacteria , local government departments have begun to continuously compress the fence area of hairy crab farming since 2001, which was reduced to 86,000 mu in 2002 and 32,000 mu in 2007.
In early 2016, Suzhou City issued the "Suzhou Yangcheng Lake Ecological Optimization Action Implementation Plan" to further ensure drinking water safety, and Yangcheng Lake was clearly positioned as a source of drinking water. According to the requirements of the implementation plan, by the end of that year, the fence farming area in the lake area will be reduced by half and turned into 16,000 mu.
A farmer at Yangcheng Lake Roadside Market told reporters that in the past two or three years, the news that the fence area will continue to decrease will come from time to time. Now farmers have signed two-year contracts with the government. Whether they can continue to raise crabs in two years depends on the government's arrangements.
"The fence area will be reduced" and "Yangcheng Lake hairy crabs will become fewer and fewer", but the sales of hairy crabs seem to be even more popular in the aquatic wholesale market. "New Crab King Aquatic Product Wholesale Market" is the largest market around Yangcheng Lake. When the reporter came here, he found that the entire market was bustling and busy. Consumers watched and bought crabs, and crab merchants packaged and shipped crabs, and the business looked particularly hot.
Dealer Mr. Chen has been breeding hairy crabs by Yangcheng Lake for fifteen years. He is vividly aware of the changes in the water quality of Yangcheng Lake.
Mr. Chen said that in the past few years, hairy crabs were raised in large areas, all of which were cyanobacteria.
Cyanobacteria are known as water quality warning lights and are manifestations of eutrophication of water bodies. Cyanobacteria will erupt in some waters of Yangcheng Lake. Nowadays, the area of the hairy crab farming fence of Lao Chen has decreased from the initial 80 acres to more than 10 acres. Lao Chen introduced that the hairy crabs raised in Yangcheng Lake were originally made from the wild fish and shrimps in the lake as food. However, as the breeding volume continued to increase, the small fish and shrimps in the lake were far from enough to eat. Crab farmers began to feed sea fish and corn to the hairy crabs in the lake, and they had to feed 30 kilograms of hairy fish at a time per acre of land.
At the breeding site of Yangcheng Lake hairy crabs, the reporter saw with his own eyes and fed hairy crabs. The breeder used a shovel to throw the newly mixed hairtail and corn feed to the water again and again. After more than ten minutes, all 360 kilograms of hairtail and corn were fed to 10 acres of water. Some hairtail pieces were still very large because they were not stirred and chopped again. The white fish pieces were floating in the wind on the green water surface.
360 kilograms of hairtail and corn were fed into 10 acres of water.
reporter learned that during aquaculture, only a small part of the nitrogen and phosphorus that are put into the aquaculture water in the form of feed or nutrients will be assimilated by fish and crabs, while the rest will bring nitrogen, phosphorus, ammonia and other loads to the water. In fact, farmers and operators know that feeding iced hairtail and corn kernels in large quantities like this will definitely cause pollution. The breeder said that the number of hairtail fish that is invested in Yangcheng Lake every day is about 240,000 kilograms.
is an ice fish distribution site in Yangcheng Lake Town. The dealer said that in the past few days, twenty tons of ice fish have been transported to various crab breeding areas located in Yangcheng Lake, and around Yangcheng Lake, there are fifteen such sales sites. In a farmers' market in Shipai Town, the owner of an ice fish seller said that during peak hours, her family could sell 10,000 kilograms of ice fish a day.
Ice Fish Dealer said that starting from March 25, it was fed until early December, and more than 1,000 tons were sold.
Cold storage at the ice fish sales point.
pond crab farming is more than four times that of lake crabs
Yangcheng Lake environmental governance has a long way to go
As the investigation deepens, the reporter found that the number of ice fish sellers sold far exceeds the feeding needs of hairy crabs farmed in Yangcheng Lake lining. Under the reporter's questioning, a dealer gave an amazing answer. It turns out that in recent years, villagers in villages around Yangcheng Lake have dug their farmland into ponds, introduced the water of Yangcheng Lake, and started to make a living for hairy crab breeding.
The reporter used a drone to shoot and found that the Xiaojing Village in Yangchenghu Town and other surrounding villages were surrounded by scattered crab ponds. The area of crab farming ponds in this area alone is at least about 10,000 acres.
hairy crab farming pond.
Yangcheng Lake is currently a source of drinking water in Suzhou, but with the continuous development of surrounding industries, breeding, tourism and real estate, the environmental pressure carried by Yangcheng Lake is becoming increasingly greater. The local government has publicly issued the "Yangcheng Lake Water Pollution and Blue Algae Monitoring and Early Warning Work Plan" for three consecutive years. At present, there is an embarrassing situation for the breeding of hairy crabs in the Yangcheng Lake Basin to breed on the shore. The crabs in the pond are also fed with ice fish and corn, and the water in the pond is changed every year. The farmed wastewater flows back into the lake. In this way, the pollution caused by the farming wastewater does not seem to be reduced at all, and it is still returned to Yangcheng Lake.
Researcher at the Institute of Microbiology, Chinese Academy of Sciences Liu Shuangjiang said that feeding means eutrophication, because the nutrient nitrogen and phosphorus you add are high. There will always be some residual things discharged into the lake in the crab pond, or crab excretion. The nitrogen and phosphorus in the lake are very high, eutrophication will lead to bad water quality, such as algae outbreaks and some microbial community imbalances.
At the Suzhou Environmental Monitoring Center, the reporter saw the change table of water quality in Yangcheng Lake. From 2007 to 2019, the permanganate, ammonia nitrogen, and total nitrogen indexes in water quality all showed a huge decline. However, the reporter also found that since 2016, the index of total phosphorus has remained at around 0.06 mg/liter, and there has been no major change in four years. The total phosphorus index is 0.06 mg/liter. belongs to the fourth category of water source standard , and the fourth category of water sources are mainly suitable for general industrial water areas and entertainment water areas where the human body is not directly in contact with. According to the requirements of my country's " Surface Water Environmental Quality Standard ", only Class III or above water sources can be used as drinking water sources.
Yangcheng Lake water quality change table.
Yangcheng Lake is an important water source in the Taihu Lake Basin. Currently, is the second water source in Suzhou Industrial Park and also the backup emergency water source in Suzhou . The construction of the second water source is nearing its end. It is expected to be completed by the end of this year. Crab farming in the lake will be managed, but pond crab farming on the shore will emerge. At present, the changes in the water quality of Yangcheng Lake have attracted the attention of the Suzhou Municipal Ecological Environment Bureau.
Zhang Chao, director of Taihu Water Pollution Prevention and Control Department of Suzhou Ecological Environment Bureau, said that how to ensure the stable compliance of the water effluent of the standardized transformed pond is also a matter of consultation with relevant departments to promote it in the next step to ensure that the amount of this pollutant is further reduced or that it does not cause major pollution.
"Economic Half Hour" Observation:
How can crabs go ashore and pollute into the lake!
Yangcheng Lake is the second source of drinking water for Suzhou. In order to protect the water source and implement the national ecological civilization construction requirements, local governments have compressed the area of Yangcheng Lake sequestration breeding to the current 16,000 mu, and the annual output is only about 1,300 tons. This number is only 1/10 of the peak of Yangcheng Lake breeding.The rectification efforts are of great importance, but another more serious fact is that while the area of the lake fence is reduced, the area of aquaculture ponds built along the lake area of Yangcheng Lake is increasing, reaching 74,800 mu, which is four times the area of the lake fence, and the production of crabs is calculated in tens of thousands of tons.
Pond crab farming pumps water from the lake. After raising crabs, the pond water polluted after raising them will be returned to Yangcheng Lake in a drop. In the next year, these ponds will continue to extract the water from Yangcheng Lake and start breeding. " crabs come ashore and pollution enter the lake ", which is repeated again and again. The more you control the Yangcheng Lake, the more polluted it is.
Recently, in order to coordinate the implementation of ecological protection red lines, the General Office of the CPC Central Committee and the General Office of the State Council issued the "Guiding Opinions on Coordinating the Demarcation and Implementation of Three Control Lines in Land Space Planning", which clearly put forward the basic principle of "bottom line thinking and protection priority". We hope that while developing the economy, local governments will not break through the red line of ecological construction. In this way, the "crab" will eventually be destroyed.
(The original title is "Exposed! Yangcheng Lake water pollution endangers the crab business! Where does the hairy crab you bought come from?")
Editor: Wang Dan
