High-yield culture techniques of crayfish

Select Pond

The source of water requires fresh water quality, sufficient dissolved oxygen and no pollution. It is better to take loam clay as the best, the width of the pond is more than 3 meters, the slope is 1 ∶ 2.5-3 meters, the water depth is 0.8-1.5 meters, the PH value is 7.5-8.5, the pond area should not be too large, generally 3-8 mu, rectangular, east-west. When injecting new water into the pond, filter it with 20-40 mesh gauze to prevent wild fish and fish eggs from entering the pond with the flow of water. According to the pattern of high irrigation and low discharge, the drainage canal should be built so that it can be irrigated and discharged. Crayfish has a strong escape ability, so it is necessary to do a good job in the construction of escape prevention facilities. Usually plastic film, mesh, calcium plastic board or cement board are used to set up anti-escape facilities along the ridge of the pond to avoid the entry of enemy creatures and the escape of crayfish.

Clear pond disinfection

Pond cleaning disinfection can effectively kill enemy organisms in the pond (catfish, Loach, snakehead, snake, rat, etc.), wild miscellaneous fish (common carp, crucian carp, etc.), and pathogens. Quicklime and bleach can be used, which is economical, economical and safe. The specific operation methods are as follows:

1. Disinfection with quicklime. Dry disinfection: 70 kilograms of quicklime per mu, sprinkle the whole pool with chemical water, and then hug with nail rake if possible, after a week in the pond, inject new water; disinfect with water: the surface of each mu is calculated according to the water depth of 1 meter, and 130 kilograms of quicklime is dissolved in the water. Sprinkle evenly in the whole pool.

2. Bleach disinfection. After the bleach containing 30% available chlorine was completely dissolved, the whole pool was evenly sprinkled with a dosage of 25 kg per mu.

Plant aquatic plants

"how about lobster? is there any grass in the pond? The lobster is not big, but the grass in the pond is in charge. " Aquatic plants play an important role in lobster culture. First, aquatic plants can fill the insufficient intake of lobster bait and supplement a large number of vitamins; second, they can prevent wind and waves, absorb some harmful substances in the water body, purify the water quality, and balance the water environment; third, it can provide shelter and habitat for young shrimp and shelled shrimp, reducing the number of strong bullies. Generally speaking, the planting area of aquatic plants accounts for half of the total area of the pond. Varieties are available: low-stem Reed, Potamogeton crispus, bitter grass, goldfish algae, wild horns, Zizania caduciflora, Zizania latifolia, Rabdosia malayensis, Elodea verticillata and so on. If possible, you can also put some empty cans, bamboo tubes, tree roots and other wastes at the bottom of the water body, which are crayfish's favorite habitats.

Fertilization in shrimp ponds

Some people think that it doesn't matter whether the lobster is fertilized in the pond or not. in fact, applying an appropriate amount of organic fertilizer to the shrimp pond to cultivate bait organisms can directly provide natural bait for the shrimp after entering the pond. 400 kg / mu of fermented organic fertilizer was selected to maintain the corresponding fertility of the pond water. In the process of feeding, with the gradual deepening of the water level, to apply mature organic fertilizer, the amount and time should be determined according to the fat and thin of the water, generally not more than 80kg each time. The transparency of the pool water is kept at about 35 cm.

Lobster stocking

Lobster seedling release can be divided into spring release and autumn release. It requires neat specifications, complete appendages, no disease, no injury, and release the foot at one time. Wash with 5% salt water for 5-10 minutes before stocking to kill parasites and pathogenic bacteria. For the purchased shrimp species, due to long-distance transportation from the water, the seedlings should be soaked in the pond for 1 minute before entering the pond, lifted and shelved for 3 minutes, and then soaked for 1 minute, so that the seedlings should be soaked for 3 times, so that the body surface and Gill cavity of the seedlings can absorb enough water before stocking, which can improve the survival rate. From the experience of farmers for many years, the survival rate of shrimp seedlings transported from abroad is very low after long-distance transportation. Proper mixed culture of silver carp and bighead carp in the pond can improve water quality and make full use of bait resources.

1. Release adult shrimp in spring: 5000-6000 young shrimp with a length of 3 cm to 5 cm were released in the middle of March.

2. Breeding parent shrimp in autumn: around September, 500 lobster parent shrimp were artificially selected per mu, with a female-to-male ratio of 3 ∶ 1.

Feed selection

Lobster is omnivorous, animal feed, plant feed and all kinds of artificial feed should be used in different stages. Animal feed mainly includes small fish chips, dried fish meal, snail clam meat and all kinds of animal offal, while plant feed mainly includes rapeseed cake, soybean meal, wheat, corn, pumpkin and all kinds of vegetables and upland grass.

Feeding and management

Crayfish lie dormant for many days and go out at night, and it is their habit to hunt for food at night. Feed should be fed at 10: 00 a. M. and 4: 00 p. M. every day, and the amount of feed in the afternoon accounts for about 70% of the daily feed.

The suitable water temperature for the rapid growth of crayfish is 22 ℃ 32 min. The food intake of crayfish increases gradually from June to October, and the daily feed can be adjusted according to the actual fishing situation, and at the same time, it can be increased or decreased according to the weather, water quality and shrimp activities. Cast less when the rain is heavy, and feed the shrimp in sunny days.

Daily management

Lobster culture should also patrol the pond every day, pay attention to changes in water color and lobster activities. If shrimp are found to come ashore or climb on aquatic plants and refuse to enter the water, check whether the water is lack of oxygen or the water quality is deteriorating, and take corresponding measures such as increasing oxygen and changing water. The pH value should be kept at about 7.5, and the transparency is about 35 cm. Change the water every semimonthly in April, May and June, and every ten days in July, August and September. Sprinkle quicklime water every 20 days, using 10 kg / mu of quicklime each time. The water level rises gradually from spring to midsummer, and the maximum depth is not more than 1.5m. Maintain the normal growth of aquatic plants and a certain coverage area. Try to keep the surrounding environment quiet when the lobster molts, and increase the feeding of animal palatable feed after molting so as to reduce the killing of each other. Lobster disease is much less than other aquatic products, but it can not be ignored, daily emphasis is on prevention. It is the nature of lobsters to like to escape, especially in the flood season to strengthen inspection and strictly prevent escaping shrimps.

Lobster fishing

Lobster fishing tools are mainly ground cages, and the specific operation method is to set up ground cages near aquatic plants in the pond, fasten both ends of the ground cages, and collect lobsters that meet the commercial specifications from the ground cages the next day. In addition, you can use a handmade net or drain the pool water to catch the lobster by hand. Lobster fishing can adopt the way of catching large and small, and rotating fishing, which is conducive to increasing production, starting in May and ending fully at the end of September.