Comprehensive collection of Australian freshwater lobster farming techniques (Part 1)

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Breeding experiments show that the survival temperature range of red crayfish is 5～35℃, and the suitable growth temperature is 13～28℃. When the water temperature exceeds 4 mg / liter during the breeding process, and the dissolved oxygen level should be higher during the incubation process. ? 4.Reproduction and Growth? Red crayfish have no definite breeding season. When the water temperature is between 20～30℃, they can reproduce all year round and spawn multiple times. If they are captured, moved, have poor water quality or lack oxygen during this period, they are more likely to die. ? 1. Selection of broodstock ? (1) Broodstock requirements require the selection of adult shrimps with strong vitality, complete appendages, smooth bodies, and no attachments and diseases (such as tail rot and shell damage) as broodstock. ? 2.Raising and cultivation of broodstock? Adult shrimps raised in earthen ponds must be bathed in formalin with a concentration of 20010-6? before entering the overwintering pond80 square meters, or even more than 2000 square meters. The water body is large and the water quality is relatively stable; for small-scale production, the cultivation pond can be several to more than ten square meters. In order to prevent cannibalism of broodstock, bamboo baskets, hanging nets, moso bamboo and other shelters are added to high-density stocking breeding tanks. ? (3) Cultivation and management of broodstock Because broodstock has a small number of eggs, the survival rate during broodstock cultivation must be increased to ensure the yield of seed production. The feeding amount is generally 4%～5% of the broodstock's body weight, and can be increased or decreased depending on its eating conditions. However, observations during the production process show that when the water temperature is lower than 9℃, the mortality rate of broodstock shrimps about 3 centimeters is very high during the overwintering period. Although adult shrimps can survive, a large number of deaths will occur 2~3 months later. Red-clawed crayfish can generally lay eggs 2～3 times a year. The breeding period is 5～10 months, and the peak period is 6～? 3.The spawning and hatching of red crayfish? After the overwintering period, the gonads of the broodstock mature. It is reported that the number of eggs in the second year of broodstock of the same size is greater than the number of eggs in the first lay. ? (2) Incubation conditions From the eggs that have been fertilized in vitro to the time when the juvenile shrimps leave the mother and live independently, it will take about 42 days of cultivation under suitable conditions. Control at 26～28℃. Like other crustaceans, in the suitable temperature range, the higher the water temperature, the shorter the incubation time. If it encounters low temperature, and the water temperature is as low as 20℃, the change will be large, and the fertilized eggs will easily fall off or water mold will develop, causing embryonic death.