The "ban on fishing" in Taihu Lake seems imperative. Recently, in order to ensure the comprehensive withdrawal of the protected area before October 15, three working groups of the Jiangsu Provincial Leading Group for promoting the prohibition of fishing and retiring in the Yangtze River Basin have been stationed in Taihu Lake, Hongze Lake and other waters to supervise.
Recently, in order to protect the aquatic biological resources of Taihu Lake and promote the effective improvement of the ecological environment of the water area, the Department of Agriculture and Rural Affairs of Jiangsu Province issued Announcement No. 12, deciding to withdraw the fishing rights of fishery producers in Taihu Lake on October 1 this year, withdraw fishing licenses, and cancel relevant certificates. Fishermen will be compensated accordingly in accordance with the law.
This also means that in the 49 professional fishing villages (communities) in the 49 professional fishing villages (counties and cities) of Suzhou, Wuxi, Changzhou and Huzhou in the 4 cities and 15 districts (counties and cities) along the Taihu Lake, more than 10,000 fishermen on 5370 fishing boats will bid farewell to decades of traditional fishing work.
According to Wang Xiaolin, director of the Office of the Taihu Lake Fisheries Management Committee (hereinafter referred to as the "Taihu Lake Fishery Management Office"), in the future, in addition to the 400,000 mu of Taihu Lake Protected Area, a third-party agency will assess the fishery resources of Taihu Lake and formulate a more scientific and reasonable fishing policy. The fishing time, fishing scale and fishing methods of taihu lake fisheries will usher in great changes.
Every fish mussel disappears
Both indicate ecological deterioration
As a pearl in the Yangtze River Delta, Taihu Lake is a lake sandwiched between high-rise buildings and is also the lake most affected by human activities. Among them, fishing has become one of the most important social functions of Taihu Lake.
The abundant aquatic resources of Taihu Lake have always been a source of livelihood for fishermen. According to historical statistics, there were 107 species of fish in the Taihu Lake Basin. "In May and June, first catch silver fish with small nets, and then make shrimp trawl nets to catch plum fish and white shrimp in autumn, and after October, you can catch some big fish under the fast silk net." Old Wu, a native of Wuxing, Huzhou, has been fishing in Taihu Lake for nearly 40 years, and he remembers that in his early years, there were still many river eels and rouge fish in the lake, and occasionally a few puffer fish and anchovies.
However, in 2003, environmentalists found that the cochineal fish, a fish species unique to the Yangtze River Basin, has been extinct in the Taihu Lake Basin. "At that time, the fish market was very good, and some people specially used special wire nets to catch them." In Lao Wu's memory, after the mid-1990s, many of the previously common fish species disappeared.
Three years ago, a new survey showed that there were fewer than 50 species of fish in Taihu Lake, and more than half of them disappeared within a few decades. The natural populations of bluefish, silver carp, bighead carp, eels and other natural populations in Taihu Lake are mainly relying on artificial release.
Since 2009 alone, the Taihu Lake Fish Festival has stocked more than 600 million fishing fry of various types for ten consecutive years. This year, the Taihu Lake Basin is expected to release another 120 million fish such as silver carp and silver carp.
It is not only the fish that disappear, but the mollusks that are more critical of the water environment disappear faster. According to the Freshwater Fisheries Research Center of the Chinese Academy of Fishery Sciences, there were more than 20 kinds of molluscs in Taihu Lake, compared with less than 10 species that were common four years ago.
The disappearance of every fish and mussel is a symptom of the ecological changes of the entire lake.
Damming, pollution, and fishing are all threatening taihu fish
In the view of fish researchers, habitat occupation, water pollution, and overfishing are the main causes of the destruction of fishery resources.
Comparing the historical recorded fish list, many of the species that disappeared in Taihu Lake are migratory fish. They usually spawn in the Yangtze River in the spring, and when the river floods in the summer, the growing fry and adult fish swim back to the lake in search of more food. But this long-standing reproductive habit is being altered by human activities.
Since 1958, Taihu Lake has successively built sluice gates along the river and the mouth of the river, and then has continued to excavate flood discharge channels and build water conservancy projects such as levees around the lake, resulting in the blockage of fish migration channels. Chang Jianbo, director of the Institute of Water Ecology at the School of Water Resources and Hydropower of Wuhan University, once gave a public interview that a large number of waterways through the Yangtze River Basin have been controlled by the construction of gates, and only a few lakes such as Poyang Lake and Dongting Lake can go to the fish.
Overfishing is another "culprit" in accelerating the decline of fishery resources. A few years ago, the fishery resources survey of the Taihu Lake Fishery Management Office showed that most of the fish species that were released in Taihu Lake (commonly known as "bream"), silver carp, bighead carp, and cocked-billed bream (commonly known as "Taihu Lake whitefish") were under 2 years old, which showed that the fish species that were only released in that year had basically been caught.
Gao ta net is also the main fishing method of Taihu Lake fishery, two fishing nets are enclosed together, nearly 2 kilometers long fishing range, can be underwater "net exhausted" in a short period of time. In recent years, the Taihu Lake Fishery Management Office has been shortening the fishing time of the high-pedal net, but in the 25 days from September 6 to the end of the fishing, the catch of high-stepping nets can account for 60% of the total number of fish in the lake.
Behind the changes in the ecology of the lake is the surge in fishery production. Between 2009 and 2015, the fishery production of Taihu Lake increased from more than 43,000 tons to more than 56,000 tons, with an average annual growth rate of 1,941 tons. Last year, the fishery output of Taihu Lake exceeded 72,000 tons, an all-time high.
In addition to overfishing, many fishermen talked about the changes in the water quality of Taihu Lake.
On a high-net fishing boat in Yixing, the 55-year-old fisherman Qian still remembers the lake water in early 2000. "It's a dirty mess, the shore is full of oil and green algae, and even the fish have lost their taste." In the most aggrieved one, the fishmonger who bought him refused to pay because the fish hit by the old money smelled of diesel.
Until now, Taihu Lake is still one of the key watersheds of the state. The water quality assessment jointly compiled by the Taihu Lake Basin shows that in 1987, the organic matter pollution on the surface of Taihu Lake was still 1%, and after 1993, Taihu Lake has shown a trend of total eutrophication. More than two-thirds of the Taihu Lake Basin shows a trend of degradation of ecological services (referring to all products and services provided by ecology for human production and life).
The total ban on fishing and retiring has become the best choice for restoring the ecology of Taihu Lake.
Fundamental changes are possible in the Taihu lake fishery
For the upcoming ten-year ban on fishing and retiring fishing in Taihu Lake, the relevant person in charge of the Taihu Lake Fishery Management Office introduced: Taihu Lake fishing withdrawal is a decision made by Jiangsu Province out of the need to protect the aquatic biological resources of Taihu Lake and promote the improvement of the ecological environment of the waters. However, retiring fishing does not mean a long-term ban on fishing, and in the future, scientific utilization of water surface planning will be studied for non-protected areas, and aquaculture fisheries will be developed and fished in an organized manner.
A relevant expert from Zhejiang Ocean University told reporters that the breeding fishery can harvest fishery production by releasing artificial breeding seedlings into Taihu Lake and taking appropriate protection measures to maintain ecological balance and biodiversity.
To this end, he gave an example of the Man's needleless squid that once produced nearly 500,000 tons in the waters around Zhejiang in the 1990s was basically extinct. In the early 21st century, the research team and divers found a small string of squid fertilized eggs in Zhoushan, and through the study of human breeding techniques, they carried out breeding and stocking experiments in 2005. Today, the resources of Zhejiang Man's needleless squid have risen from endangered to more than 5,000 tons.
Yuan Julin, deputy director of the Zhejiang Freshwater fisheries research institute, stressed that the ban on fishing and retiring fishing can not only protect biodiversity, but also help form a population structure of different ages, "just like human society, there are old people, adults, and children who will be balanced." ”
In the future, the fishing methods, time and scale of the Taihu Lake fishery may undergo fundamental changes. The mesh size and size of the fishing nets will be standardized, and the fishing time will be scientifically arranged according to the growth cycle and population size of the fish and shrimp, and a more scientific and orderly fishing will be developed through the time limit mechanism.
"Many fish and shrimp, the life expectancy is one or two years, not fishing will also cause waste." The Taihu Lake Fisheries Management Office said that it will next invite a third-party professional organization to assess the fishery resources of Taihu Lake and organize the fishing of Taihu Lake aquatic products in the form of professional fishing companies.
Yuanju Lin is very happy, and now the awareness of the protection of fish is increasing. "If you release 1 kilogram of flowers and silver carp, you can consume 40 kilograms of blue-green algae." He said that while protecting fishery resources, it is to maintain the ecological health of the Taihu Lake basin.
(The original title "Taihu Lake once had more than 20 kinds of molluscs, and 4 years ago there were less than 10 common species, since 1993, Taihu Lake has all shown a eutrophication trend Why does Taihu Lake retire from fishing Can we still eat Taihu lake fish", the original author Yu Renfei Chen Xi. Edited by Lu Sichao)