Chinese sturgeons mainly live in my country’s offshore continental shelf waters and migrate to the Yangtze River when breeding. There are also distribution records in the Pearl River and Minjiang River in my country. Listed as endangered by the World Conservation Union (IUCN).
Chinese sturgeon is very precious. It is a rare "living fossil" that first appeared in the Mesozoic Era 150 million years ago. In terms of taxonomic status, the Chinese sturgeon is between cartilaginous fish and bony fish. Its bones are cartilage and its body has hard bony scales. It is a cartilaginous teleost fish. Chinese sturgeon occupies an extremely important position in classification and is an important reference for studying fish evolution.
In recent years, water pollution has been detrimental to the gonad development of Chinese sturgeon broodstock, the hatching of fertilized eggs in natural reproduction, and the growth and development of young sturgeons. Affected by water pollution, the distribution range of juvenile sturgeons in the Yangtze River Estuary has been significantly reduced. For example, before the 1970s, juvenile Chinese sturgeons were one of the four main fishing targets in Hangzhou Bay. Currently, it is difficult to find traces of juvenile sturgeons in this water area. Young sturgeons in the Yangtze River Estuary have also developed liver cancer due to water pollution. After the 1980s, the sex ratio in the spawning population of Chinese sturgeons has been seriously imbalanced. The female to male ratio has reached 3:1 or even 5:1. The sperm motility of male Chinese sturgeon broodstock has declined year by year, which may also be directly related to the water quality of the Yangtze River.
The construction of the Gezhouba Water Conservancy Project has also affected the living environment of the Chinese sturgeon. Before the construction of this project, spawning Chinese sturgeons traveled upstream to the Jinsha River. After Gezhouba cut off the Yangtze River waterway, migrating Chinese sturgeons could only reach below the dam. The spawning river section was reduced from the original 800 kilometers to 7 kilometers. The number of spawning grounds has been reduced from the original 16 to 1-2, and the area of ??the spawning grounds is only 0.4 square kilometers. This has caused a sharp decrease in the number of spawning and migrating Chinese sturgeons.
Another reason for the decline in the number of Chinese sturgeons is artificial fishing. Although the Chinese sturgeon has been listed as a national first-level protected animal since 1988, a considerable number of Chinese sturgeons are still accidentally caught and illegally fished every year. In the Yichang River section alone, between 1986 and 1996, fishermen accidentally caught and released 155 Chinese sturgeons, and some fishing gear along the river also caused serious damage to young sturgeon resources. Surveys show that from 1988 to 1992, only on the eastern beachhead of Chongming Island in the Yangtze Estuary and some of its extended shoals, where juvenile Chinese sturgeons are concentrated, the total bycatch of young sturgeons each year ranged from 6,350 to 7,060. In addition, the decrease in the number of Chinese sturgeons is also due to its own and other reasons, such as a higher age at first sexual maturity, a long interval between repeated reproductions, a low survival rate of fertilized eggs, and a low survival rate of its own reproduction.
In the early 1980s, after the construction of the Gezhouba Water Conservancy Project on the Yangtze River, the migration channel of Chinese sturgeons from the sea to the river for breeding was cut off, which had a serious impact on the survival of Chinese sturgeons. As early as the mid-1950s, when the Yangtze River Basin planning began, national leaders proposed the need to study the impact of the construction of the Gezhouba Water Conservancy Project on fish migration and spawning grounds. At that time, a group of scientific and technological personnel and The leaders of the competent departments insisted on opening an opening in the dam and adding a 12-meter-wide fish passage facility - a fishway. Two scientists, Wu Xianwen and Cao Wenxuan, academicians of the Chinese Academy of Sciences, based on the rich scientific data accumulated by the Institute of Hydrobiology of the Chinese Academy of Sciences over more than 20 years of fish resource surveys in the Yangtze River and the "fish overcoming problems" carried out by the Institute of Hydrobiology, the University of Hydraulic and Electric Power over the past few years. The actual data of "flow rate capacity" and the series of compensation measures taken by sturgeon-producing countries such as the former Soviet Union, Europe and the United States to protect and increase their resources were reviewed and investigated. Withstanding the pressure of public opinion from all aspects of society, we resolutely proposed the "Gezhouba Hub" The construction will not have a significant impact on the spawning grounds of domestic fish." "The Gezhouba hub blocks the migration channel of the Chinese sturgeon, which has serious adverse effects on this fish and must be rescued." "Artificial breeding and release measures should mainly be adopted. Fish-passing facilities should not be built.” "Chinese sturgeons are large in size and have very strict requirements on water flow conditions when traveling upstream. What's more, compared to the wide river surface and rapid river water, Chinese sturgeons cannot find a 12-meter-wide fishway." Based on the natural environmental conditions and hydrological data of the Yangtze River, we boldly infer that after the dam is built, Chinese sturgeons may form new spawning grounds under the dam for natural reproduction.
This was the "Gezhouba Fish Channel Dispute" that shocked the whole country at that time. Academician Wu Xianwen wrote this point of view into a proposal and submitted it to the central government, which was affirmed and adopted by the national leaders. This suggestion saved the country 53 million yuan in investment and became a big news at that time for scientists and democrats to participate in political discussions. Facts have proved that the Chinese sturgeons that entered the river to breed quickly adapted to the new environment and formed a new spawning ground in the lower reaches of the Gezhouba River.
After the construction of the Gezhouba Water Conservancy Project, although the Chinese sturgeon has a new spawning site, this breeding site is no longer what it used to be, from a 600-kilometer river section to only a 7-kilometer river section. With the launch of the Three Gorges Project, once the project is completed and put into operation, a large amount of water will be stored in the Three Gorges Reservoir in October, and the reservoir water level will increase to 175 meters, then the discharged water flow will be reduced by 41%. In this way, the Chinese Sturgeon Yichang Spawning Ground will be seriously affected, and the area of ??the spawning river section will be reduced again. In order to protect the eternal survival of this rare animal, my country has been accelerating research on artificial breeding of Chinese sturgeons since 1980, and releases 10,000 to 20,000 artificially bred young sturgeons into the Yangtze River every year; the Fuzhou Municipal Government also in 2001 In December, 7,000 young sturgeons were released into the Minjiang River. According to expert estimates, in order to achieve the effect of restoring the resource proliferation of Chinese sturgeons, at least 100,000 Chinese sturgeons must be released into the Yangtze River every year. This must be supplemented by effective protection measures, and the fishing of Chinese sturgeons must be completely prohibited and strictly restricted. Use fish for scientific research to maximize the preservation of spawning sturgeon populations.
In order to protect the proliferation of Chinese sturgeons, the country and relevant localities have adopted a variety of protection measures.
In 1988, the Chinese sturgeon was listed as a national first-level protected animal.
In 1996, the Hubei Provincial People's Government approved the establishment of the Yichang Chinese Sturgeon Nature Reserve.
In 2002, the Shanghai Municipal People's Government approved the establishment of the Yangtze Estuary Chinese Sturgeon Juvenile Nature Reserve.
Establish Yichang and Jingzhou Chinese sturgeon protection stations. In the ten years from 1986 to 1996, fishermen accidentally caught and released 155 Chinese sturgeons in the Yichang River section alone.
A Chinese sturgeon juvenile rescue station has been established to rescue and care for accidentally caught and injured juvenile Chinese sturgeons. Dozens to hundreds of juvenile sturgeons can be rescued and released every year. Artificial breeding is carried out and the young sturgeons are released into the Yangtze River. In the 1970s, artificial breeding of Chinese sturgeons achieved initial success in the spawning grounds of the Jinsha River, and a small amount of them were released. In 1983, the Yangtze River Fisheries Research Institute of China Fisheries Research Institute and other units successfully carried out artificial breeding under the Gezhou Dam and also conducted artificial releases. Since then, the former Chinese Sturgeon Research Institute of the Ministry of Water Resources has also successfully carried out artificial breeding. As the technology of artificial breeding of Chinese sturgeons becomes increasingly mature, especially the artificial breeding of Chinese sturgeons, releases can be carried out in a planned manner. The continuous improvement of Chinese sturgeon breeding technology makes large-scale artificial releases possible. The current marking method can also distinguish artificially released and naturally bred young sturgeons. Since 1997, the Yangtze River Fisheries Research Institute has made new breakthroughs in Chinese sturgeon seed breeding technology. The survival rate of large-scale breeding of Chinese sturgeons has reached 80 or higher. In 1998, about 80,000 Chinese sturgeon juveniles with a body length of 12-20 cm were cultivated. , greatly breaking the historical record and laying the foundation for large-scale artificial release.
From 1983 to the end of 1998, several scientific research institutes released approximately 5.8 million Chinese sturgeons of various sizes into the Yangtze River, Min River, Pearl River and other waters. By the end of 2004, approximately 600,000 10-centimeter Chinese sturgeon seedlings had been released into the Yangtze River waters. Since 1981, more than 6 million Chinese sturgeons of various sizes and more than 1,000 large-size Chinese sturgeon fry have been released.
It is prohibited to hunt Chinese sturgeons to protect water quality.