catalogue
1. Living habits
2. Morphological characteristics
3. Distribution range
4. Breeding technology
5. Nutritional value
Living habits
Acipenser sinensis is a kind of benthic fish, which has a very narrow feeding habit and belongs to carnivorous fish. It mainly feeds on some small or slow-moving benthos, mainly marine 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. Early juvenile fish living in the middle and upper reaches of the Yangtze River feed on chironomid larvae, dragonfly larvae, mayfly larvae and plant debris. Young fish in the salty and fresh water area of the estuary feed on shrimp, crab and small fish.
In Compendium of Materia Medica, its eating habits are recorded as follows: it eats with its mouth open, listens to it, eats without drinking, and crabs and fish eat by mistake. In fact, the Chinese sturgeon sucks food by the expansion and contraction of the oral membrane, and most of the food objects are small animals living on the mud surface or trapped in the mud residue. The Chinese sturgeon basically does not eat during the whole migration and detention period from the ocean to the river. Therefore, the energy consumption of Chinese sturgeon in fresh water and the nutrition needed for gonadal development depend on a large amount of fat and other substances accumulated in its body before entering fresh water. Therefore, in fresh water, the closer to a mature individual, the thinner the body.
Migrating Chinese sturgeon is a large migratory fish. Usually, the Chinese sturgeon inhabits the coastal continental shelf from the north to the west coast of Korea and the south to the southeast coast of China. After living in the ocean for 9- 18 years, when the gonads are nearly mature, they migrate to the Yangtze River in groups and reach Yibin, Sichuan in the upper reaches of the Yangtze River and the lower reaches of Jinsha River for reproduction. Every summer and autumn, they gather at the mouth of the Yangtze River, go upstream to the Jinsha River in the upper reaches of the Yangtze River to lay eggs, take young sturgeons downstream and grow in the deep waters of the East China Sea and the Yellow Sea. However, the construction of some hydropower stations in the Yangtze River has made this kind of fish lose its spawning and breeding places in the Yangtze River, completely blocking the migration route of Chinese sturgeon. Unreasonable human activities have seriously damaged the ecological environment of the Yangtze River and the ecosystem of Chinese sturgeon. Acipenser sinensis has a long migration route, low viability and is vulnerable to external damage. Once this species resource is destroyed, it is difficult to recover.
morphological character
Acipenser sinensis has a spindle-shaped body, a blue-gray or grayish-brown head and back, a grayish-white abdomen and gray fins. There are no thorns in the whole body, only a small amount of hard bones. A row of beautiful bone plates on the back, two rows of beautiful bone plates on the side and five rows of cartilaginous vertebrae support a huge body. Generally, there are 8~ 16 bone plates in front of dorsal fin, 0~3 behind dorsal fin, 26 ~ 42 on body side and 8~ 16 on ventral side. The head is in the shape of the Yangtze River Delta, and the bone plate at the back of the head is smooth.
The front of the eyes is flat, plow-shaped and upturned. The mouth is on the ventral side of the head, forming a transverse fissure, and the mouth can freely expand and contract. There are horny nipples on the upper and lower lips. Four beards are juxtaposed in front of the mouth. Eyes are very small. There are spray holes behind the eyes. The branchial foramen is large, and the branchial membrane is connected with the isthmus. Gill harrows are short columns, thin and sharp, with 14~28 pieces, generally about 18 pieces.
distribution range
Chinese sturgeon is the only sturgeon that crosses the Tropic of Cancer. It is mainly distributed in the coastal areas and major rivers south of the west coast of the Korean Peninsula, 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, among which the Yangtze River produces more. But at present, only the middle and lower reaches of the Yangtze River and offshore waters have been discovered, and other rivers have disappeared.
Acipenser sinensis all appeared in the Upper Cretaceous at the end of Mesozoic, about 65.438+0.4 billion years ago. China once found sturgeon fossils in the Late Jurassic strata of Beipiao, Liaoning Province (65.438+0.4 billion years ago), and named them 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.
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; Shidao, Yellow River, Yangtze River, Qiantang River, Ningbo 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.
breeding technology
water temperature
Acipenser sinensis is a warm-water fish, which adapts to a wide range of water temperatures. Under the condition of artificial culture, the survival water temperature of ACIPENSER sinensis in Dongtai ACIPENSER sinensis nature reserve is 0 ~ 37℃, the suitable water temperature for growth is 13 ~ 25℃, and the optimum water temperature for growth is 20 ~ 22℃. The suitable water temperature for parent sturgeon spawning is 17 ~ 24.5℃. The optimum incubation temperature of fish eggs is 65438 07 ~ 265438 0℃. After winter, when the water temperature dropped to 9 ~ 16℃, the Chinese sturgeon ate less, grew stagnant and even lost weight. Before and after beginning of spring, the water temperature gradually rose to 10 ~ 13℃, and a small amount of food began to be eaten, and the growth was slow. After Tomb-Sweeping Day, the water temperature rose above 65438 05℃, and the feeding became active and the growth accelerated. When the water temperature reaches 33 ~ 38℃, the Chinese sturgeon cannot move normally.
Oxygen content: ACIPENSER sinensis requires high dissolved oxygen, which is generally above 5 mg/L in water. If the dissolved oxygen in the water drops to 4 mg/L, the appetite of Chinese sturgeon will decrease. When the dissolved oxygen continuously drops to or below 3 mg/L, the food intake of ACIPENSER sinensis decreases rapidly, even stops eating, which leads to slow activity, coma and even suffocation in severe cases. It is worth pointing out that the fat water with a wide range of dissolved oxygen is not suitable as the water source for the cultivation of Chinese sturgeon larvae and juveniles.
PH value: ACIPENSER sinensis is suitable for living in weak alkaline water with pH value of 7.0 ~ 8.0. When the pH value drops, it means that the carbon dioxide in the water increases, the acidity increases and the dissolved oxygen decreases, which is not good for the Chinese sturgeon which needs higher dissolved oxygen. When the pH value is too high, it will increase the toxic effect of ammonia nitrogen in water, which is also unfavorable to the culture of Chinese sturgeon.
Salinity: ACIPENSER sinensis is a kind of euryhaline fish, which has a wide range of salinity tolerance. Under natural conditions, it moves between salt water and fresh water, breeds in fresh water and grows in seawater.
Light intensity: In the vertical swimming stage, fry have strong phototaxis. After turning to benthic organisms, phototaxis disappears. Generally, the light intensity has no obvious effect on the breeding of young sturgeon, but to avoid the sharp rise of water temperature caused by direct sunlight in summer, shading facilities should be installed above the breeding pool.
Bottom material: young sturgeons and young sturgeons have high requirements for bottom material, and the bottom of the pond is required to be smooth and pollution-free; Adult sturgeons have no strict requirements on sediment, as long as it is sediment.
Transparency: Transparency reflects the quantity of plankton, mud and other suspended substances in water. In the breeding stage of larvae and juveniles, the transparency should be controlled at 40 ~ 60 cm, the excreta should be removed in time and the daily management should be strengthened. In the feeding stage of adult sturgeon, the transparency can be controlled at about 30 cm to meet its requirements.
Ammonia nitrogen: Ammonia nitrogen is mainly decomposed from organic matter in aquaculture ponds. Acipenser sinensis will suffer from diseases such as decreased vitality, poor growth, gill rot and even a large number of deaths if it lives in water with high ammonia nitrogen for a long time. The ammonia nitrogen of young sturgeons should not exceed 0.2 mg/L.
At present, the larvae and juveniles of Chinese sturgeon have no obvious habit of going upstream, and prefer to concentrate in Shuikou. In a culture pond with an area of 3 ~ 10, the suitable water flow is 10 ~ 20L/min.
Velocity: The average velocity of Chinese sturgeon spawning is between 1.0 ~ 2.0m/s, and the flow pattern is very complicated. Generally, they lay eggs at the bend of the river, with deep pools, eddies and boulders in the flow field.
nutritive value
Acipenser sinensis has a series of primitive characteristics, which makes it between cartilaginous fish (sharks, etc.). ) and teleost fish, and they are primitive species in teleost fish, so they have important academic value in the evolutionary history of fish.
At the same time, because of its large size, delicious meat and eggs, and high nutritional and medicinal value of traditional Chinese medicine, Compendium of Materia Medica records that its liver is mainly used to treat boils and scabies, its meat supplements deficiency qi and bathes blood, its nose meat supplements deficiency qi, and its seeds are like adzuki beans, which are healthy to eat and kill worms in the abdomen. Leather can be tanned; The swim bladder, known as the stomach of bighead carp, is rich in gum and can be used to make first-class paints and medicines. Meat tastes delicious; Spine and nasal bones are excellent delicacies, known as shark wings and sturgeon bones, which can prolong life, nourish yin and strengthen yang; The bone plate formed by hard phosphorus on the body surface is the material for making handicrafts; In the distribution area, it has been the most important fishery object since ancient times, which has caused them to be destroyed by a large number of fishing, thus causing serious damage to the Chinese sturgeon resources.