How to breed sturgeon?

I. Overview of sturgeon culture technology From a technical point of view, it is much easier to develop sturgeon and conduct large-scale artificial culture than mandarin fish and soft-shelled turtle. If cheap feed can be used, the feed conversion rate is high, the breeding cost is low, and the added value of sturgeon breeding is large. Sturgeon is an excellent breed with strong adaptability and disease resistance. (1) Artificial propagation It is reported that at present, the species of artificial propagation in various countries in the world mainly include small sturgeon, paddlefish, high-headed sturgeon, Russian sturgeon, Chinese sturgeon, European sturgeon, sturgeon schrenckii, bighead carp and more than a dozen hybrids. Selecting excellent parent fish is the key to artificial propagation. Whether fishing in natural waters or artificial breeding, it is required that the gonad development of parent fish reach the fourth stage. If the parent fish is not fully mature, it can be temporarily raised in cages or ponds, or combined with oxytocin injection to promote its gonad maturity. The techniques of egg collection, fertilization, deboning and hatching of sturgeon are basically the same as those of carp, but the requirements for hatching temperature are more stringent. Generally, the suitable incubation temperature is 15-20℃, and the seedlings emerge in about 7 days. If the ambient temperature changes suddenly, the incubation will be seriously affected. (2) fry cultivation sturgeon fry cultivation can be divided into two stages: early stage and late stage. Pre-culture can start from the disappearance of yolk of fry to culture in a separate pond. Its main bait is Artemia nauplii, aquatic oligochaetes, copepods and other active bait, supplemented with appropriate amount of egg yolk and artificial compound feed. In the later stage, artificial compound feed is generally used, and biological bait such as small fish and shrimp can also be fed in moderation. 1997, Russian scholars successfully studied two kinds of special feeds for sturgeon, and the results were very good. See table 1 for the main nutritional components and contents. Ost-4 is suitable for feeding stage of 12-40g juvenile sturgeon. Ost-2 is suitable for breeding period with weight over 40 grams. In addition, in order to promote the development of sturgeon, foreign scholars have also developed many bioactive agents. The survival rate of 8-20-day-old juvenile sturgeon can be increased by 12%- 18% if it is treated with bovine pine cone polypeptide preparation (BPP for short), and the treated juvenile sturgeon can also eliminate or degrade the toxic effect of heavy metals. See Table 2. The experiment also showed that adding 2 mg of Komarine Kormogrizin and 0.2 mg of vitamin C to each kilogram of feed, after mixing evenly, can enhance the digestion and absorption ability of sturgeon and increase the yield of young sturgeon by 10%-45%. Treating the young sturgeon with the following three bioactive substances can greatly improve the early embryonic development and survival rate of the young sturgeon: First, soaking the fertilized egg 1 hour with the peptide liquid SKB with the concentration of 400 mg/L extracted from chicken plasma can increase the survival rate of the young sturgeon by 21%-22%; Secondly, the survival rate of young sturgeons can be improved by 20%-25% by using the polynucleotide solution eneade with the concentration of 5 mg/L extracted from yeast and soaking fertilized eggs 1 hour; Thirdly, the survival rate of young sturgeons can be improved by 26%-30% by using the plant antitoxin Epine extracted from sphagnum, with the concentration of 10-7 mg/L and soaking fertilized eggs 1 hour. (3) Adult sturgeon culture can be divided into small water body culture and large water body culture. The former includes outdoor cement ponds, water tanks, earth ponds, canals, cage culture and so on. Generally, large fish species are intensively cultivated, and the specifications can reach about 2 kilograms in a year or so; The latter are stocked in lakes and reservoirs, and most of them are polyculture rough processing. Relationship between quality and stocking density of juvenile sturgeon cultured in ponds. One of the important tasks of industrial culture of sturgeon is to obtain high-quality fish species. In order to meet the demand for fish species in industrial culture, Russia is currently conducting high-density culture experiments under pond culture conditions, and the stocking density is 0/.5 million fish per mu, which is 1.5-3 times of the standard stocking density (0.5- 1 10,000 fish per mu). This experiment was divided into seven groups with different stocking densities. The stocking densities are 5000, 6500, 8000, 9300, 10000, 12000 and 15000 per mu respectively, and the feeding time is 40 days. It can be seen that increasing stocking density will affect the growth of young sturgeon. When young sturgeons are cultured in ponds, the amount of bait resources should be considered, and the stocking density should not exceed120,000 per hectare. Second, the artificial propagation technology of ACIPENSER schrenckii, also known as ACIPENSER schrenckii and ACIPENSER schrenckii, is a large economic fish produced in Heilongjiang. In recent years, aquaculture has been developed in northern China. (1) aquaculture technology 1. Selection and Maturity Identification of Fish The artificially propagated parent fish generally adopts the naturally matured parent fish in Heilongjiang waters. Collecting and catching time is the breeding season from May to July every year. Individuals aged 9- 13 were selected, who had no diseases or injuries. The weight of females was over 15 kg, and that of males was over 20 kg. The breeding interval of female fish is 3-5 years. Male and female individuals in non-reproductive period have no obvious characteristics. Male and female fish in the breeding period are different, but there is no marriage color and idolatrous imitation. The specific identification method is: the mature female who wants to give birth is thin, with a lot of mucus on the body surface, a thin and soft abdominal wall and an enlarged and elastic abdomen. There is no obvious change in body color and body shape of male individuals, and most individuals weighing more than 20 kg are mature. During the inspection, it was found that the tail of the fish was bent into a "bow" shape, and the semen flowed out by gently pressing the reproductive hole with your hand. At this time, the male fish can breed as the parent fish. 2. Artificial induction of labor can be carried out when the water temperature rises to 16-24℃. When the water temperature is low, the effect of oxytocin lasts longer. Lrh-a is often used as oxytocin. The injection method and dosage depend on the maturity of the parent fish. The basic dose is 60-90 micrograms per kilogram of female fish. Generally, if the polarization index of an egg reaches 1/30 or above, ovulation can be induced at stage ⅳ. The total dose of induced labor is divided into two injections, the first dose is 10%, and when the polarization index reaches 1/55 or above, the remaining dose is injected. The male fish uses half the dose of the female fish and is injected at the second injection of the female fish. For men with good maturity, no injection is needed. The injection site is generally the root of pectoral fin. After spawning, the female fish and the male fish are temporarily kept in separate pools and stimulated by running water. Pay attention to parent fish activities and regularly check fish body changes. When the female begins to ovulate, she swims actively and hits the water frequently. After examination, obvious signs of ovarian flow can be found. When the abdomen is gently pressed to the genital hole, the eggs can be taken. The time for taking eggs can be controlled within 90 min and not more than 150 min at most, otherwise the fertilization rate will be affected. From the relationship between time and water temperature, when the average water temperature is 16.5℃, the action time is 18 hours; When the average water temperature is 19℃, the action time is about11h. 3. Egg collection and fertilization: collect semen by squeezing. An individual weighing 20 kg can excrete 30 ml of semen at a time, or even more. Male fish can be used many times. High quality semen is pure milk-like. Take eggs by laparotomy or push them by hand. An individual weighing 15 kg can lay 2.5-3.5 kg of eggs, about 9-120,000. Semi-dry artificial insemination. The dosage of semen is per kilogram of fish eggs 10 ml. When using semen, dilute it with sterile water first. The dilution ratio is semen to water 1: 200. During insemination, the semen is put into the fish eggs, stirred evenly for 3-4 minutes, so that the sperm and the eggs are fully combined, left for a period of time, and the sewage is discarded and rinsed. The eggs of ACIPENSER schrenckii are sticky, which usually appear in 5-6 minutes after fertilization, and reach the maximum viscosity in 15- 18 minutes, so the eggs must be boned before hatching. Most of the debonding agents are talcum powder or fine yellow mud. The former is made into 20% aqueous solution, and the latter is made into 10% concentration. When deboning, pour the water solution on the fish eggs and keep stirring to prevent caking. When the fish eggs are all dispersed and granular, the debonding effect can be achieved by standing without caking. Debonding time usually takes 30-60 minutes. The fertilized egg can hatch after bone removal. 4. The eggs hatched by ACIPENSER schrenckii are large and heavy, about 40,000 per kilogram. It is best to hatch under the condition of running water, or stir the eggs regularly. The special incubator is generally 380 cm× 65 cm× 30 cm, with water inlet and drainage system and regular egg shifting device, which can hatch 400,000 eggs of ACIPENSER schrenckii at one time. When hatching, the water is 5-60L/min, and the automatic egg transfer device is used once every minute, and the hatching rate is about 85%. In addition, double cages can also be used for hatching. The size of the cage is 80 cm× 60 cm× 50 cm, and each hatch is 1 kg of eggs. The method is that in Jiangwan with clear water quality and water flow speed of 0.8- 1.5 m/s, the cage is fixed and floated, and the eggs are turned every 20 minutes, and the hatching rate is also about 85%. The incubation temperature is 16-24℃, and the optimum temperature is 19-22℃. In this range, when the water temperature is high, the film emerges early and the emergence is concentrated, and when the water temperature is low, the emergence is late and the emergence time is long. When the average water temperature is 17℃, the film is released for about105h; When the average water temperature is 265438 0.5℃, the film is released for about 865438±0h h. The newly hatched larvae are1.1-1.3cm long and move vertically like tadpoles. After 70 h incubation at 2 1℃, swimming spots appeared, so you can swim horizontally. (2) fry cultivation technology 1. Outdoor common cement ponds can be used for fish ponds, with a single pond area of about 300m2 and a water depth of 1.5-2m. It is best to use well water that meets fishery water quality standards. Clean and disinfect the pond before breeding. 2. The size of stockings is 18-30cm, and the weight is 50-90g. The specifications of stocking in the same pond should be neat and consistent in size, and the fry of different specifications should be stocked in different ponds. The stocking density is 0.5- 1.0 per square meter. Soak the fish in 5% salt water for 20 minutes before entering the pool, and start feeding the fish the next day after entering the pool. 3. Earthworms can be used to domesticate the bait at the initial stage of feeding, and then gradually changed to artificial compound feed. The composition of artificial compound feed is: crude protein 37.82%, crude fat 5.96%, crude fiber 8.48%, ash 14.9 1%, nitrogen-free extract 20.55%, water 12.28%, and the particle size is 2.0-3.0mm per day. 4. During feeding, keep the water level above 1.5m, the water temperature below 26℃ and the dissolved oxygen at 6 mg/L (Wang Yutang National Aquatic Technology Extension Station).