Culture techniques of Penaeus vannamei

Penaeus vannamei is one of the three excellent species with the highest cultivation yield in the world (the other two species are Penaeus monodon and Penaeus chinensis). It has fast growth, strong disease resistance and remarkable economic benefits. Healthy farming, that is, ecological farming, requires that a good water environment must be maintained in the breeding process, to avoid and reduce the invasion of pathogens and environmental pollution, to advocate scientific and reasonable breeding management measures, to take the road of comprehensive disease prevention and control, that is, to prevent and control diseases, to maintain the ecological balance of aquaculture and the basis for aquaculture development.

pond condition

1. Culture site: Semi-intensive culture pond can be reconstructed on the basis of existing seawater shrimp culture pond. The area is generally 40-50 mu, the depth of the pond is 1.5 meters, the bottom of the pond is flat and inclined to the drain, and the inlet and drain should be strictly separated. The larger the distance, the better. The intensive culture pond is generally about 10 mu, the pond depth is 2.5-3 meters, it is best to be circular or square to form an arc shape, the bottom of the pond is inclined to the center, and the drain is located in the center of the pond. The area of factory culture pond is 400-600㎡/piece. The pool depth is more than 1.5 meters.

2. Thorough pond cleaning and disinfection: ponds must be cleaned, disinfected and exposed before stocking. After the bottom mud is removed from the pond, 70-80kg/mu quicklime slurry is evenly sprinkled to kill harmful organisms and pathogenic organisms in the pond; after 3-4 days of drying the pond, the pond is washed with lime water; 5-10cm of water is added to make the pH value of the pond water be 8.0 - 8.6, and then the long-acting water disinfectant, bromochlorohydantoin, etc. are sprinkled in the whole pond according to the dosage of 200-250g/mu to completely kill pathogenic organisms and harmful organisms.

pre-seedling preparation

1, water quality conditions: water quality requirements fresh, pollution-free, dissolved oxygen above 5mg/L, PH 7.8-8.5, transparency 30-40cm, bottom H2S concentration does not exceed 0.01ppm.

2, equipped with breeding machine: the intensive culture pond, semi-intensive culture pond pond must be equipped with breeding machine. The quantity of equipment shall be determined according to the planned yield index, such as 400kg per mu, 0.5 sets of 1.1 kW motor frequency 50 Hz shall be configured per mu, and 0.8 sets shall be configured if the yield index is 600kg per mu. In the concrete production, the 1.1 kilowatt breeding machine can provide oxygen for the water surface of 4 mu shrimp culture.

Culturing basal food organisms

Before shrimp larvae enter the pond, cultivating enough basic food organisms is the key measure to improve the survival rate of shrimp larvae, strengthen the physique of shrimp larvae and accelerate the growth of shrimp larvae in the early stage of shrimp culture. At the same time, food organisms play an important role in purifying water quality, absorbing harmful substances such as ammonia nitrogen and hydrogen sulfide in water, reducing shrimp diseases and stabilizing water quality.

The time of cultivating basic food organisms is determined according to different cultivation methods and water absorption methods. Generally, the culture pond is carried out 10-15 days before the seedlings are released, and the culture method can be carried out about one week after the pond is cleaned, the water is 50cm, and the organic fertilizer and chemical fertilizer are applied to culture the basic bait organisms. Applying urea 3kg/mu, calcium superphosphate 0.5kg/mu, or sprinkling active bacteria 0.5g-1g/cubic meter in the whole pond, the pond water will be yellow-green or tea-brown, the transparency 25- 40cm, and the ph value will be about 8.0. Fertilization amount should be controlled flexibly according to the bottom quality of shrimp pond.

shrimp stocking

1. Shrimp fry selection: to select healthy and lively, uniform specifications, clean body surface, full intestinal tract, sensitive reflection, large body transparency, no focus, strong vitality of white shrimp fry.

2, specifications: general specifications for 1.0-1.2cm, preferably more than 1.5cm body length.

3. Timely stocking: The optimum growth temperature of Penaeus vannamei larvae is 22℃-35℃. In this water temperature range, the stocking shrimp larvae grow fast, feed large, have strong constitution and strong disease resistance.

4. stocking density: 1.5- 20,000 shrimp/mu in general shrimp pond, 20,000 - 30,000 shrimp/mu in semi-intensive culture, 30,000 - 40,000 shrimp/mu in intensive culture pond, 200 shrimp/square meter in factory culture, and more than 100,000 shrimp/mu. The specific stocking density depends on pond conditions, culture technology and management level.

When stocking shrimp seedlings, we should do a good job of "mixing water", so that the temperature of the seedling bag and the temperature of the pool water are basically consistent, then we can open the bag for stocking at the pool and left and right sides of the wind.

feeding management

1. Regulation of pond water color: The ideal water color for culture of Penaeus vannamei is yellow-green or yellow-brown formed by green algae or diatoms. The conventional regulation method is to apply nitrogen and phosphorus in proportion to the pond water. In the middle and late stages of cultivation, due to the increase of residual bait and shrimp feces, the color becomes darker, and appropriate water change, water addition or application of certain zeolite powder or quicklime to control the color.

2, maintain the ecological balance of shrimp ponds: practice has proved that where there are few plankton ponds, shrimp disease early, body length only 5cm may be sick; on the contrary, body length more than 8cm to see individual shrimp body disease. Harmful substances such as ammonia nitrogen and hydrogen sulfide in suspended water can increase dissolved oxygen in pool water, improve water quality environment and bottom quality conditions for shrimp growth, and reduce shrimp harm. Generally, 3 days after disinfection of the pond, 1 kg/mu of active micro-ecological agent is mixed in the sand, scattered on the bottom of the pond, and then sprinkled with 2g/m3 of substrate modifier when receiving water, fertilizer water and fertilizer water, which can effectively maintain the ecological balance of the shrimp pond.

3, control the pH of the pool water, dissolved oxygen, transparency: in the culture process of Penaeus vannamei should pay attention to adjust the pH value, should not be too high, otherwise it will increase the toxicity of ammonia nitrogen, inhibit the growth of shrimp. With the growth of shrimp culture, the demand of shrimp for dissolved oxygen in water is also increasing. In the early stage, the oxygenator should be intermittently turned on according to the water quality, and then the start-up time should be gradually extended. In the middle and late stages of intensive culture pond and factory high-density culture pond, it is necessary to start 24 hours to ensure that the dissolved oxygen content in the pond water is above 5mg/L, and the dissolved oxygen content in the bottom layer of the pond is above 3mg/L, and the minimum can not be lower than 1.2 mg/L. In the early stage of cultivation, the transparency should be maintained at 25-40cm, and in the middle and late stages should be maintained at 35-60cm. If the transparency is less than 20cm, appropriate water, water or zeolite powder and quicklime should be added. If the transparency is too large, appropriate nitrogen and phosphorus fertilizer can be applied to regulate the water quality.

4, feeding: generally feeding cheap chilled fish paste and shellfish, but also feeding some compound bait. Feed quantity should be determined according to shrimp size, survival rate, water quality, weather, feed quality and other factors. The daily feeding rate is 8-10% of shrimp body weight in early stage (1-3cm), 5-7% in middle stage (3- 10cm) and 3-4% in late stage. Feeding several times a day, feeding at night accounted for 60-70%.

5. Daily management: patrol the pond every morning, noon, evening and midnight to observe the water color and prawn activity, growth and satiety rate, so as to adjust the feeding amount and whether to open the aerator.

Control techniques of shrimp diseases

30-60 days after seedling is the high incidence period of viral diseases of Penaeus vannamei, during which different disease prevention measures should be taken:

1, biological disease prevention: the use of active microecological agents or substrate improvers to regulate water quality, adding active feed microorganisms, FRC-vitality source additives, etc., can effectively improve the intestinal function of shrimp, increase its absorption rate of feed, and inhibit the occurrence of bacteria, enhance the immune capacity of the body, promote shrimp growth.

2, drug disease prevention: every 10-15 days, the whole pool can be sprinkled with bromochlorohydantoin, dibromohydantoin, dichlorohydantoin and other hydantoin disinfectants once, the dosage of 0.2ppm-0.3ppm. For oral use, shrimp growth promoter, pure Chinese medicine preparation, FRc-vitality source additive, immune enhancer and other green products can be added to feed frequently. It can enhance immunity of shrimp, remove harmful substances in shrimp body, and play the role of preventing and treating diseases.