Freshwater lobster is also called crayfish. In recent years, crayfish have become pets on the table and their worth has doubled. It is predicted that there will be no saturation phenomenon in the crayfish market in the next five years, and crayfish farming has rapidly developed throughout the country. After several years of production practice, the author believes that the crayfish stocking should pay attention to the following matters:
The mouth of Tongkou, which is selected for cultivation of crayfish, is moderate in size, generally ranging from 20 mu to 50 mu. Tanggu slope ratio is larger, in the 1:2.5 to 1:3, easy to crayfish burrowing, breeding, and can reduce crawfish escape. The pond is rich in natural food organisms and aquatic plants.
Thoroughly clear the pond crayfish 10 days before stocking, pumping pool water, 100 kg of lime per acre, completely clear the pond. Kills predators and various pathogens. Apply 100 kg to 200 kg of organic fertilizer per acre to cultivate food organisms.
Ecological planting plants planted along the shallow water around the pool, water plants accounted for 40% to 60% of the pond area, species are Vallisneria, Elodea, black leaf algae, Eichhornia crassipes, water lilies, etc., both for feeding crayfish, but also It is the ideal place for hidden and inhabited crayfish. In addition, the bottom of the pool can also be tied with water grass into a haystack, every 5 meters to put a pile of 5 kilograms to 10 kilograms each, sinking in the water, put 15 heaps ~ 20 heaps per acre. The haystack was tied with a rope and the other end of the rope was fixed to the water.
The choice of species of shrimp is not fully grasped by the current artificial breeding of crayfish, crayfish species are mainly based on natural reproduction, so the choice of species of shrimp is particularly important. The time for picking and stocking crayfish is generally between the end of August and mid-October and can be harvested from farm ponds or natural waters. Male and female broodstock are required to come from different waters to reduce inbreeding. The time for the broodstock to leave the water should not exceed 2 hours. In indoor or humid environments, the time may be longer. Identification of male and female: (1) The first and second gastropods of males evolved into white, calcareous tubular connectors; the first gastropods of females were degenerated and the second gastropods were pinnate. (2) The genital opening of the male is not obvious at the base of the fifth pair of thoracic foot. The gonad of the female is open at the base of the third pair of thoracic feet, and a pair of dark circular holes are apparent. (3) shrimps with similar body length, large chewing claws of males, long and obvious spinous processes on wrists and palm joints, and relatively small chelate claws of females.
The broodstock that are stocked by broodstock need to be physically strong, have appendages intact, and have uniform specifications, and should have enough time to avoid stocking in batches, which can reduce killing each other. When stocking broodstock, it should be evenly stocked along the pool and evenly distributed. Long-distance transport of broodstock, stocking first put the broodstock soaked in water for 3 minutes to 5 minutes, and then put the pool side 2 minutes to 3 minutes, repeated 2 to 3 times, so that the broodstock suck enough water, then slowly When the broodstock is placed in the pool, the survival rate of the broodstock can be increased. The proportion of broodstock to males and females is usually 2 to 3:1. Crayfish can spawn in autumn and winter, and the mating season is generally September to December. At the beginning of March of the following year, when the temperature rises to 12°C and the water temperature rises above 10°C, shrimp will leave the cave and come out for feeding and activities. At this time, management should be strengthened and artificial feed should be started. When the water temperature reaches 18°C ​​or more, feed more. When a large number of juveniles have hatched, the broodstock that has been bred can be harvested in a cage.
Stocking density is mainly cultivated in crayfish ponds, with 30 kg to 40 kg of aquacultured shrimp per acre, and a specification of 30 g/above. The broodstock will be fed artificial feed in time after stocking, and will be caught in cages and lobster cages in April of the following year. Stay small, the annual output of 200 kg ~ 300 kg. Each year is only harvested every year, no need to plant seeds. It should be noted that fishing should not be excessive. If fishing is excessive, the output in the coming year will inevitably be greatly reduced. The polyculture ponds contain 10 kg to 20 kg of aquaculture shrimp per acre, and the specifications are about 25 g/ton. They do not feed feeds. They mainly use natural pond food and bait-reserving baits. In April of the following year, they begin to use cages to catch fish and catch large fish. Small, mu production is generally 50 kg to 100 kg.
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