Long kiss? Fry reproduction
(1) broodstock selection. The broodstock is best caught in the wild fish in rivers and weighs more than 2 kilograms. It is good if it is older than 4 years old. Females should choose short genital process, wide and round gonads, ruddy color, large fish abdomen, obvious ovary outline on the abdomen, touch soft and flexible; males choose reproductive spiky and long, generally not easy to squeeze out Semen, as long as its end is bright red. In ponds with better water sources, use small trash fish as bait. (2) Production. The ratio of male to female at natural spawning is generally 1:1 or 2:3. Artificial insemination is 3:1. The water temperature for inducing production is 20-28°C, and the optimum water temperature is 23-25°C. If a single injection is used, females use LRH-A30-50 μg plus PG0.5-1.5 kg/kg of body weight. If two injections are used, the first needle is 1/5-1/4 of the total dose, and the interval between the two needles is 10-12 hours; the male dose is halved and the full dose is injected only once in the second injection of females. The injection site is the base of the chest or back muscles. The effect time is usually 19-22 hours. Natural spawning and artificial egg fertilization can be used. The use of artificial insemination is more ideal, can increase the fertilization rate, fish fry specifications, easy management. The key to artificial insemination is to grasp the time of fertilization. Generally, the effect is good about 2 hours after estrus. The fertilization rate can reach more than 90%. (3) Incubation. Natural spawning can be left in the original spawning pond for microfluidic water incubation and fixed screens at the outlet to avoid larval loss. For artificial insemination eggs, polyethylene mesh sheets can be used to adhere the eggs, or they can be adhered to the "foil" and placed in microfluidic tanks for hatching. The hatching water temperature is 22-25 °C. The optimum incubation temperature is (251)°C. Below 20 °C or higher than 28 °C or when the temperature of hatching water temperature exceeds 3 °C, it is unfavorable for hatching. Dissolved oxygen is required above 7 mg/l. The pH is around 8 and the ammonia nitrogen is below 0.03 mg/l. When the embryo develops to the early stage of embryonic body twisting, the dead eggs must be removed and then the eggs or mesh pieces are placed in a cage to continue hatching until the fish seedlings emerge. When the water temperature is 24.5-27.5°C, incubation takes 32-45 hours. When the water temperature is 22.5-24°C, it takes about 60 hours.
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