The Yangtze River is the largest river in my country and has important value in water supply, shipping, power generation and other fields. It can be called the "river of wealth" of the Chinese nation. At the same time, the Yangtze River is also an ancient river of life. The Jinsha River and Min-Tuo River basins in the upper reaches, the Dongting Lake and the Poyang Lake basins in the middle, and the Taihu basins in the lower reaches are all included, and a huge ecological blueprint is about to emerge.
In October 2022, a paper "takes the pulse" of the Yangtze River was released. The information of the article is heartbreaking: the Yangtze River has about 30% fish in a worrying situation, and the existing resources are only equivalent to 0.9% in the 160s. What happened to the Yangtze River, which is known as the "fish gene bank" in ? Can ecological fishing bans save Yangtze River fish? I believe many netizens have doubts about this.
Yangtze River: The treasure house of resources of the Chinese nation
As an important ecological treasure house, the Yangtze River has created a world-renowned miracle of life. Various aquatic organisms have reached more than 54,300 species of . Fish, shrimp and crab and even higher mammals (such as baiji, etc.) have evolved naturally in the river. According to statistics, more than 5440 fish are inhabited by the Yangtze River Basin, ranking first in the country's water system. Among them, there are about 5140 species of special fish. The rich resources have laid a deep foundation for the Yangtze River fishery.
centered on the Three Gorges River section, and the relationship between the Yangtze River and fish can be described as "blood is thicker than water". From Chongqing to Yichang , the water range is about 650km and the drop is 120m. The unique hydrological conditions have made the largest spawning ground in my country's history: green grass silver carp and bighead carp , the famous Yangtze River antler, knife fish , kelp , etc. all migrate here to lay eggs.
The production time of fish eggs is consistent with the monsoon climate of the Yangtze River. A large number of fertilized eggs hatch in the rolling water waves. When they drift to the wide downstream of the water surface, the eggs just hatch into fry . The young fish stay in fertile waters such as Hukou and Hewan for food. After they mature, they go upstream again and enter a new round of life cycle. The reproduction cycle of fish is perfectly coupled with the hydrological laws of the Yangtze River, and the traceability habits are transformed into genetic imprints, vividly reflecting the beauty of evolution.
However, the situation of "Mother River" is not purely natural and without interference, and human activities are the biggest variable. From ancient times to the present, rivers and lakes in the middle and lower reaches of the Yangtze River have been crisscrossed and plains spread out. On this basis, people have surrounded the lake and built fields, created fertile arable land, and built countless buildings. The result is the shrinkage of wetlands, the habitat environment is damaged, and the water purification capacity is reduced.
Especially since 1970, the economy along the Yangtze River has developed rapidly, and population density has increased, and subsequently, the intensification of water pollution. Monitoring data shows that the eutrophication lakes in the Yangtze River have increased from 10 in 2008 to 61 in 2018. Taihu Lake, Dianchi , and Chaohu frequently occur. The country has invested tens of billions of governance costs and has not eradicated hidden dangers. The water quality problems along rivers and lakes are becoming increasingly prominent.
The biodiversity of the Yangtze River
What is even more regrettable is that the biodiversity of the Yangtze River has also declined, and many ancient creatures that have survived for millions of years have fallen into the dilemma of endangered extinction. The White Dolphin and White Sturgeon are both "living fossils" species of the Yangtze River and are also flagship species located at the top of the Yangtze River food chain. Their disappearance means that the Yangtze River has suffered from "ecological diseases". If the status quo is not changed, more rare species may suffer the same bad luck.
The crisis of the Yangtze River: Two major resource surveys, 135 species of fish disappeared
The crisis of the Yangtze River fishery resources was clearly visible in the two major surveys. The first large-scale special investigation was launched from 1973 to 1975. sausage , knife fish, Chinese sturgeon , four large fish , etc. were valued for their high yield and great economic value. The background of this investigation is quite subtle: the key fish in the Yangtze River begins to show obvious trends of miniaturization and younger age, the proportion of high-quality fish in medium and high trophic grades has dropped significantly, and a crisis is brewing.
According to the deployment, Anhui Province is mainly responsible for the investigation of resources such as knife fish and shad fish in the Anhui section. Researchers found that not only the fishing volume of adult fish has decreased, but the output of fry is also sharply decreasing.Taking the production of the Saikou Fisheries Brigade in Wangjiang County as an example, the output of each "fry net" was as high as 5.43 million in 1959, and in 1973 it dropped sharply to 563,000 , with a reduction of 85% . The main reason is that the egg laying scale of migratory fish such as green grass, silver carp, bighead carp, etc.
fry reduction and the decline in adult fish size point to the same problem, that is, the attenuation of breeding scale. However, the provinces along the river did not reduce the fishing efforts, but instead increased the output by increasing the quantity. In order to increase production and income, fishermen understood the activity rules of fishing schools, supplemented by reforming fishing gear and fishing methods, and fishing production remained at a high level in the 1980s.
But the yield of some fish species cannot be sustained, and the anchovies are the most typical microcosm. By studying the migration routes of the Yangtze River's shads, fishermen in the middle and lower reaches have summarized many fishing proverbs: Jiangyin, Jiangsu is "Hi" in the "Hi" in the Grain Rain, " in the Anhui section, "Hi" in the early Qingming Festival, the grass is late, and the beginning of summer is the time for Xiaoman". In the Xiajiang, Jiangxi, the saying "Hi" in the Dragon Boat Festival, " is popular. Various places operate according to the season, and parent fish and juvenile fish are listed as fishing targets.
The fishing industry was not over until 1987, but proactive protection was one step too late, and wild resources disappeared and became the last straw that broke the fishing fish.
After the extinction of the anchovies, a special investigation on fish in the Yangtze River has not yet been launched, and "how many fish are left in the Yangtze River" has become a mystery to be solved. But old fishermen who work year-round are aware that there are obviously fewer fish in the Yangtze River and the attenuation rate is very fast, but it is difficult to give quantitative data.
Until 2017-2019, my country finally restarted the Yangtze River fish resources survey, and the relevant results "Survey on the Background Situation of Aquatic Resources and Environment of the Yangtze River (2017-2021)" were released in October 2022. The new survey contains 7 topics. In terms of species composition, there were 443 species of in the Yangtze River fish before 2017, but this survey had 135 species of not collected, accounting for as high as 30.47% of , which means that the resource decline is very serious.
Yangtze River 30% of fish disappeared. What is the reason?
First of all, natural factors can be basically eliminated, because over tens of millions of years of evolution, fish have long adapted to the environment of the Yangtze River and formed a stable survival strategy. Relatively speaking, human factors are more obvious, such as: overfishing, river dam building, sewage discharge, sand mining in rivers and lakes, etc. Some scholars pointed out that the diversity crisis of the Yangtze River has its primary and secondary texture. Control gates and hydropower stations should bear the main responsibility, and excessive fishing for fishing should bear the secondary responsibility. This statement is arguably the only thing that can be said to be.
The Yangtze River resources are in decline, and the fishing ban is just at the right time?
survey shows that the estimated number of fish in the Yangtze River Basin is .886 billion , and the resource reserves are about .1248 million tons , which is not actually high. You should know that the annual fishing volume of the Yangtze River in the 1950s was as high as more than 5.4 million tons of , which is more than three times the current total storage capacity!
Objectively speaking, the recent situation of Yangtze River fishery resources is still not optimistic, and the overall recession is in a state of decline, with the amount of resources equivalent to 27.3% in the 1950s and 58.7% in the 1980s. It is a bit gratifying that the current data reflects the resource status before the fishing ban in the Yangtze River, and the implementation of the fishing ban system is expected to change the trend of recession.
The Yangtze River has experienced great changes over the past century. Can the 10-year fishing ban be restored to its original state?
From the perspective of species structure, the biological community is always in dynamic changes, and it is not easy to recover as completely as before. From the 1950s to the 1980s, the four major fish were in the middle reaches of the Yangtze River, and the swordfish and shad fish both accounted for a relatively high proportion in the lower reaches of the Yangtze River. Now, the Yangtze River shad has been extinct for 24 years, and the swordfish has lost its scale of fish floods, and the four major fish have also reduced their production, and the fish species structure is different from the past. Of course, we still look forward to the distant "Yangtze River Elves" to reappear and prosper.
Yangtze River Anthorn: The larger ones can grow to 6-7 kilograms, generally 2-3 kilograms
On the other hand, fishing bans provide a once-in-a-lifetime protection opportunity. In less than two years, the Yangtze River fishing ban has received good news.Researchers found that the effect of fishing ban "varies from fish to fish". Fish with 1 to 2 years of sexually mature fish such as the Yangtze River swordfish recovered rapidly. The actual measured output of single network in the Chongming section of Shanghai reached 5,200 kilograms of , and , Xianning in the middle reaches of the Yangtze River was also found migrating adult swordfish. As for large fish that are sexually mature in 3 to 5 years, it will take longer to see the effect.
Within 10 years, the Yangtze River fishing ban can achieve completely visible results. According to mathematical models, the fishery resources of Poyang Lake and Dongting Lake can be restored within 3~5 years. The recovery cycle of the main stream of the Yangtze River is about 8 years. At this time, most fish will reproduce 2 or above , and the growth rate of resources will become faster and faster.
Therefore, as long as there is sufficient time for fishing bans, the ecology of the Yangtze River will definitely achieve expectations. "People do not let down the green mountains, and green mountains do not let down the green mountains." The original intention of banning fishing in the Yangtze River is the hope of "green water and green mountains".
summary
The Yangtze River is the cradle of China's freshwater fishery. The Yangtze River ecology is related to the national economy and people's livelihood and the welfare of the people. Looking back at history, the Yangtze River's natural fish production once accounted for 70% of the country, and it is necessary to retain this precious biological resource for future generations. The ban on fishing in the Yangtze River is the first step to protect resources and the most important step at the moment.
