On this magical planet-the earth, there are not only intelligent human beings, but also colorful and strange other species. Acipenser sinensis is one of my favorite species. Acipenser sinensis is a unique fish in China. Its body is spindle-shaped, covered with five layers of hard scales, and its tail is long, its mouth and abdomen are positioned, and its tail is crooked. This is a marine migratory fish, which goes upstream along the Yangtze River from Haikou to Jinsha River to Pingshan every September-165438+1October. The hatched cubs grow in the river for a period of time, and then return to the Yangtze River estuary for fattening. Every autumn, when ACIPENSER sinensis migrates upstream, a large number of ACIPENSER sinensis can be caught in each river section, so it is known as the "fish king of the Yangtze River". Adult ACIPENSER sinensis is large and heavy, with male weighing 68- 106 kg and female weighing 130-250 kg. It is said that the highest record reached 500 kilograms. Acipenser sinensis also lays many eggs. A female sturgeon can lay one million eggs at a time, but the survival rate is not high. Finally, there are still some fish. Because the Yangtze River is relatively fast, fertilization is carried out in turbulent water waves, and natural fertilization is incomplete, destroying a number of fish eggs. In the process of hatching, fertilized eggs will lose a lot if they encounter enemies such as carnivorous fish or "surf ashore". Even if they hatch into small fish, "eat small fish the Big Fish", there will still be some losses. In this way, although there are many fish eggs, not many can "grow into big fish" but carry on the family line. In fact, this is the result of reproductive adaptation during animal evolution. In the process of individual development, many species have lost a large number of young offspring; On the contrary, it is even less. This is not the arrangement of "God", but those species with less money and greater losses have been eliminated in the long river of history. Although the Chinese sturgeon is huge, it feeds on Sven, only plankton and plant debris, and occasionally eats small fish and shrimp. According to statistics, the upper reaches of the Yangtze River can produce 20,000 to 30,000 kilograms of Chinese sturgeon every year. However, in recent years, overfishing, coupled with low reproductive rate and long maturity (about 10 year), its population has been decreasing. In order to prevent the extinction of this "living fossil" which is a special product of our country, the relevant departments have listed the Chinese sturgeon as a protected object. But some specific problems still need to be solved. For example, after the completion of the Gezhouba water control project on the Yangtze River, the reproductive migration channel of Chinese sturgeon from Haikou to Jinsha River was cut off, so that pregnant female sturgeons were blocked under the dam and died. How to solve the problem of fishway in dam area is imminent. Fortunately, it is reported that the artificial propagation and release of Chinese sturgeon have been successfully tested. It will be more practical if Chinese sturgeon can settle in fresh water and breed through concrete practice. In China, sturgeon fossils were found in the Late Jurassic strata of Beipiao, Liaoning Province (10.40 billion years ago) and named Beipiao sturgeon. This sturgeon has only one line of lateral line scales on both sides, and the other body surfaces are bare, which is different from that of Chinese sturgeon with five lines of scales. Chinese sturgeon, also known as mandarin fish, is a national first-class protected animal. It belongs to cartilaginous scleroderma, with a long spindle-shaped body and a plow-shaped tail. National first-class protected animals have a wide base, a pointed tail and a slightly upturned tail. Mouth in a row, with short whiskers in front. The eyes are very small, and there is a crescent-shaped spray hole on both sides of the head behind the eyes, and the whole body is covered with five rows of prismatic bone plates. The caudal fin is curved and the upper leaf is particularly developed. Chinese sturgeon is the highest among 27 species of sturgeon in the world. It is huge and powerful, with a length of over 4m and a weight of over1000kg. Acipenser sinensis has a special physiological structure, which has the characteristics of both ancient soft-ridged fish and many modern bony fish. Shaped like a shark, the scales are like large bone plates; The fish head is sharp and the mouth is under the jaw. Some traces of biological evolution can be seen from it, so it is called a living fossil in aquatic organisms and has high scientific research value. It is a treasure in the Yangtze River! Acipenser sinensis is a rare fish among the 27 species of sturgeon existing in the world. It is the southernmost sturgeon species in the world and the oldest vertebrate on the earth. It has a history of10.40 billion years and is known as a "living fossil". Due to the world-famous Gezhouba project on the Yangtze River, the spawning migration route of Chinese sturgeon was blocked. In order not to make the production and construction of human beings affect the survival of fish, 1982, the CPC Central Committee and the State Council adopted the advice of fish experts, and designated relevant state departments to examine and approve the establishment of a professional institution for rescuing Chinese sturgeon-Gezhouba Chinese Sturgeon Research Institute. The Institute releases more than 300,000 juvenile Chinese sturgeon to the Yangtze River every year. Since the first artificial breeding in 1984, 4.44 million juvenile Chinese sturgeon of various specifications have been released into the Yangtze River, and 6,500 large mullet have been released. Gezhouba Chinese sturgeon research institute, with the primary purpose of protecting Chinese sturgeon, has diversified operations within the scope permitted by national laws and policies, and was formally established and opened to the outside world on 1993. The Chinese sturgeon Garden is located on Jiangxin Island, Jinji Road, Xiaoxita, Yichang County, Hubei Province, covering an area of 189 mu. Sturgeon Garden is strategically located, and the airport, railway station and port are close at hand. Acipenser sinensis Gray belongs to Ostracoda, Kiwifruit, Chondroscleroderma, Sturgeon, Sturgeon and Sturgeon. The body is spindle-shaped with a long kiss at the top. There are four mouths in front of the mouth. The mouth is located on the ventral side, which is elastic and can be stretched into a tube. The body is covered with five rows of vertically arranged bone plates, one on the back, two on the side and two on the abdomen, and each row has thorns. Sturgeon is a rare ancient fish left over from Mesozoic10.5 billion years ago. Between cartilage and hard bone, the degree of ossification of bone generally decreases. The central axis is an elastic notochord without ossification of vertebral body, and most of the cartilaginous shells along the skull are not ossified. The caudal fin is curved, the base of the lateral fin is broad, and the dorsal fin is opposite to the gluteal fin. The ventral fin is located in front of the dorsal fin, with spiny scales at the base of the fin and caudal fin, spiral valves in the intestine, anus and drainage holes close to the base of the ventral fin, and the opening of fallopian tube far from the ovary. Acipenser sinensis is a large individual with a long life span of up to 40 years. But its sexual maturity is late. According to the research, in the spawning population, males are generally 9 ~ 22 years old and weigh 40 ~125 kg; Female fish 16 to 29 years old, weighing 172 to 300 kg. According to the literature, it weighs 560 kilograms and is a huge fish. Because they are the largest fish in the Yangtze River, they are also called the "Yangtze River Fish King". According to observation, the average annual growth rate of ACIPENSER sinensis is relatively fast, with 5 ~ 8kg of male fish and 8 ~13kg of female fish. But it takes 8 to 14 years from young fish to large adult fish. There are 4 genera and 24 species of sturgeon in the world, including 2 species of bighead carp, 7 species of sturgeon/kloc-0, 2 species of sturgeon and 3 species of sturgeon. There are 3 genera and 8 species of sturgeon in China, including sturgeon 1 species, 6 species of sturgeon and sturgeon 1 species. The sturgeon order belongs to bony fishes in taxonomy. Because its internal bones are mostly cartilage and its body surface is covered with hard scales, it is also classified as cartilaginous fishes. Sturgeon is the most primitive fish group on the earth now. Their fossils were first discovered in Mesozoic Triassic strata (about 200 million years ago). Many species died out in the long river of earth evolution, and only a few remain today, mainly distributed in the northern part of the northern hemisphere. At present, there are 25 known species of * * * in the world, 8 of which are distributed in China. Their fossils were also found in the Late Jurassic to Cretaceous strata in China, Liaoning and Hebei provinces. Due to China's vast territory and rich ecological environment, sturgeons are rich in species and quantity and widely distributed. Their distribution is recorded from the Black Dragon River and Irtysh River in the north to the Pearl River in the south, as well as most coastal waters in China, but with the decrease of latitude, the species and quantity decrease slightly. According to 1834, the model origin of ACIPENSER sinensis is China. Although it is not a specialty of China, it is famous for its model origin in China. Later, according to the history of China at that time and the work of later generations, it was speculated that it was Guangzhou. Widely distributed in the coastal areas of Dalian, Lushun, Liaodong Bay and Liaohe in China's Bohai Sea. Islands, the Yellow River in northern Liaoning Province and the Yalu River, the border river between China and Korea; Shandong Shidao, Yellow River, Yangtze River, Qiantang River, Yongjiang River, Oujiang River, Minjiang River, Xiong Ji City, Taiwan Province Province and the Pearl River system. It can reach the lower reaches of the Yangtze River Jinsha River; In the Pearl River system, it can be traced back to Xijiang, Beijiang to Ruyuan, and even to Jiang Xun, Yujiang and Liujiang in Guangxi. It is also produced along the coast of Hainan Province. Abroad, it is found in the mouth of Han River in South Korea, Lijiang and the west side of Kyushu in Japan. At present, ACIPENSER sinensis is mainly distributed from Jinsha River to the mouth of the Yangtze River in China, and other water systems such as Ganjiang River, Xiangjiang River, Minjiang River, Qiantang River and Pearl River occasionally appear. It is generally believed that Chinese sturgeon is a freshwater fish, and they are typical upstream migratory fish. They usually live in the sea to get food and grow. Mature individuals entered the river from the sea in July and August, and after living in fresh water for one year, the gonads gradually developed. By the autumn of the following year, the breeding groups gathered in the spawning ground to breed. After spawning, the female parent fish will soon begin to dive into the river. Eggs attach to rocks or gravel at the bottom of the river. Under the condition of water temperature 17- 18℃, fertilized eggs hatch about 5-6 days and nights. The newly hatched larvae have huge yolk sacs, which are like tadpoles and drift along the river. After 12- 14 days, they begin to feed. About the next spring, the young sturgeon gradually went into the river and appeared in Chongming Island in the Yangtze River estuary from May to August. After September, the young sturgeon with a body length of 30cm left the shallow tidal flat of the Yangtze River estuary and went to sea for cultivation and growth. Acipenser sinensis is a kind of benthic fish, which has a very narrow feeding habit and belongs to carnivorous fish. In rivers, it mainly feeds on some small or slow-moving benthos, and in the ocean, it mainly feeds on fish, followed by crustaceans and molluscs. The juvenile Chinese sturgeon in the estuary mainly feeds on benthic fishes, such as Ophiuchus, pupae, krill and Agkistrodon halys, and generally stops feeding during spawning period. According to research records, because Chinese sturgeon is particularly precious, foreigners also hope to migrate it to their own rivers to breed, but Chinese sturgeon always loves its hometown. Even if some of them emigrate overseas, they have to travel thousands of miles to find their roots and migrate to their hometown rivers to have children. During their migration, they showed amazing ability to endure hunger, fatigue, find their way and identify their direction, so people nicknamed them "China". This is my favorite Chinese sturgeon.