Crawfish stocking considerations

In recent years, crayfish have become pets on the table and have become more valuable, and crayfish farming has rapidly begun. After several years of production practice, the author believes that the crayfish stocking should pay attention to the following matters:

Tangkou selection

The mouth of the cultured crayfish should have a moderate area, generally between 20 mu and 50 mu. The Tanggu slope is larger than that at 1: (2.5-3), which facilitates burrowing and breeding of crayfish and reduces the escape of crayfish. The pond is rich in natural food organisms and aquatic plants.

Thoroughly clear pond

10 days before stocking crayfish, drain the pool water and use 100 kg of lime per acre to thoroughly clear the pond. Kills predators and various pathogens. 100 kg -200 kg of organic fertilizer per acre, cultivating food organisms.

Ecological cultivation

Planting aquatic plants around the pond in shallow water, the area of ​​aquatic plants accounts for 40%-60% of the pond area. There are species such as Vallisneria, Elodea, Hydrilla verticillata, Eichhornia crassipes, Water Lilies, etc. They are both suitable for crayfish feeding and small Lobster hidden, ideal for habitat. In addition, the bottom of the pool can also be tied with water grass into a haystack, every 5 meters to put a pile, each heap 5 kg -10 kg, sinking in the water, put 15 heaps -20 heap per acre. The haystack was tied with a rope and the other end of the rope was fixed to the water.

Shrimp selection

Because the current artificial reproduction of crayfish is not fully grasped, crayfish seedlings are mainly based on natural reproduction, so the selection 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.

Broodstock stocking

Stocking broodstock requires a strong physique, complete appendages, uniform specifications, and ample footing to avoid stocking in batches, reducing mutual killing. 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 -5 minutes, then put the poolside 2 minutes -3 minutes, repeated 2 times -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 ratio of broodstock to broodstock is usually (2-3):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

The main crayfish ponds are cultivated with 30 kg-40 kg per acre, and the specifications are 30 g or more. The broodstock is fed artificial feed immediately after stocking, and the cages and shrimp cages are used for fishing in April of the following year. , 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-20 kg of aquaculture shrimp per acre, and the specifications are 25 grams/approximately. They do not feed feeds. They mainly use natural pond food and bait-reserve baits. In April of the next year, they begin to use cages to catch fish and catch large fish. Small, mu production is generally 50 kg -100 kg.

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