lobsters and crabs can be mixed, but fish can't, because lobsters like to prey on young fish.

cultivation techniques

seed selection

111 prawns with strong physique, no disease and no injury, specifications of 21-51g and the ratio of male to female of 1: 1 are selected as parent prawns, and the selected parent prawns are raised in a 6×8×l-meter cement pond covered with glass fiber reinforced plastic tiles and heating system, and the freshly chopped "lobsters" are fed every day according to 11% of the weight of the prawns in the pond. The outside of the front of the red crayfish is red and brightly colored, and the length of the claw exceeds the body length; The claws of female shrimp are basically blue, and the length is smaller than the body length. The reproductive process of mature male shrimp is obviously rod-shaped at the base of the fifth foot; The reproductive pore of female shrimp is open at the base of the third foot. Put some cleaned and disinfected nets in the parent shrimp pond as the hidden objects of the parent shrimp, suck dirt and change water every day, and keep the light at 12i: 12d (12 hours of light, 12 hours of darkness).

spawning

in late April, the parent shrimps began to mate and spawn. The mating of red crayfish is soft-shell mating. Before mating, the female shrimps have to reproduce and molt, and the female shrimps begin to lay eggs within 1.2 hours after the male shrimps produce sperm. The eggs produced by the female shrimp are dark yellow after fertilization and adhere to the empty stomach formed by the inward curling of the abdominal foot and tail fan. An egg-holding shrimp weighing 48 grams has 326 eggs, and the shrimp with high egg-holding capacity has 441 eggs, while the shrimp with low egg-holding capacity has only 27 eggs.

Embryonic development

The fertilized eggs of red crayfish are dark yellow, and gradually change to yellow orange, red orange and light gray with embryonic development. The comparative experiment of embryonic development of crayfish eggs was carried out by dividing them into four groups. The results showed that the embryonic development of crayfish eggs was extremely slow at 19℃. At the temperature of 21 ~ 23℃, the hatching time is 41 days, and young shrimps leave the mother body in 81 days. At 26℃, the fertilized eggs hatch out of the membrane in 31 days, and the young shrimp leave the mother body in 52 days; At 29 ~ 31℃, the membrane hatched in 25 days and separated from the mother body in 41 days.

larval cultivation

red crayfish larvae are hatched and collected, and then put into a soil pond for breeding. At the initial stage of growth, the larvae mainly feed on organic debris and unicellular algae such as Chlorella. Whether organic debris and unicellular algae are abundant in water is very important to improve the survival rate of crayfish larvae, and cannibalism will occur if the amount of bait is insufficient. Through the dissection of young shrimp, it is found that there are basically no zooplankton remains such as cladocera and copepods in the intestines and stomach of young shrimp, which is mainly the reason why young shrimp are not easy to obtain zooplankton because of their poor mobility. After 7 weeks of feeding, the average size of larvae can reach 7.6 cm. 5. The latest scientific method to increase the nutritional value and yield of shrimp. If the content of astaxanthin in shrimp culture is strengthened, that is, the astaxanthin content is added to the feed in proportion, that is, 2.1% astaxanthin algae powder is added to the feed in proportion, the following verified effects will be achieved (see extended reading for details):

Young shrimp:

Adult shrimp: 1.24kg/ton feed (survival rate increased by 45%, shrimp disease was significantly reduced) Usage time: 2 months before fishing.

shrimp production: 1.75 ~ 1.5 per ton of feed (41% increase in spawning). Use time: 2 months before spawning.