Pure fresh water culture of Penaeus vannamei

Shrimp seedlings with strong activity, strong ability to adapt to water, transparent body, no blackening of gills and full opening of black umbrellas were selected and reared in ponds with water temperature above 20 ℃. Strict desalination standard rough: in the early stage of culture, shrimp seedlings should be desalinated step by step, that is, desalination standard rough. Water quality requirements: the salinity change range of the pool water should not exceed 5%. The pH value is about 7.5-9.0, and the daily change range should not exceed 0.5 units.

1. Stocking shrimp fry

The main results are as follows: 1. The survival water temperature of Penaeus vannamei is about 15-25 ℃, and the best growth water temperature is 28-32 ℃. The shrimp cultured in this water temperature has a fast growth rate and a strong physique.

2. The water temperature for stocking prawns should be above 20 ℃. You can choose to release prawns in the evening or sunny days. Do not release seedlings when the sun shines directly at noon or when the water quality is cloudy in rainy days.

3. In Huanggang area, the seedlings are generally released around the end of May, and the water temperature is basically stable at about 25 ℃. The low temperature stimulation caused by the cold current can be prevented by the water temperature within this range.

4. When releasing seedlings, first put the packing bag containing shrimp seedlings into the pond and place it for about 30 minutes, so that the water temperature in the bag is consistent with that of the pond.

5. When selecting shrimp seedlings, the shrimp seedlings require strong activity, strong ability to adapt to water, transparent shrimp body, can not be without red, the cheeks are not blackened, and the black umbrella needs to be fully opened.

Second, strictly dilute the rough standard.

The main results are as follows: 1. The nursery is usually hatched in seawater with a salinity of more than 20 ‰. Although it has been desalinated for a short time, direct stocking will lead to a low survival rate or even death. So it is necessary to desalinate shrimp seedlings step by step in the early stage of culture.

2. first of all, dilute the surface coarse. before releasing seedlings, use earth dams or colored stripes to build a temporary pond in one corner of the pond, with a seedling quantity of 500-1000 tails per square meter. at the same time, crude salt and sea water essence are added to the temporary pond to adjust to the salinity of the seedling farm.

3. When releasing seedlings, the PH value should be adjusted to 7.8-8.6, the water temperature should not exceed 3 ℃, and the salinity should not exceed 3 ‰-5 ‰.

4. After 4 days of seedling release, 3-5cm pool water can be injected every day to slowly reduce the salinity of the pond. At the same time, the pool water is always kept at a depth of about 1m. We must pay attention to adjust the water color and PH value.

5. After the seedlings are put into the free-range pond, they should be fed that night, and the shrimp can be fed directly after 4 days. For the first time, the feeding amount is 5-10 grams per ten thousand tails, about 5-6 times a day, and the daily feeding amount is increased by 20-30%.

6. when the shrimp seedlings grow to more than 2 centimeters, you can stop feeding, and at the same time dig several gaps in the dam of the bulk culture pond so that they can communicate with the culture pond, so that the shrimp seedlings can freely swim out of the free culture pond, and the reasonable culture density is about 100, 000 per mu. It can be about 100000 per mu.

III. Water quality requirements

1. Penaeus vannamei is seawater shrimp, so the salinity of the pond water in the culture pond should not exceed 5%. The PH value is about 7.5-9.0, and the daily change range should not exceed 0.5 units.

2. its dissolved content is more than 4 mg per liter, the content of nitrite ammonia should not exceed 0.1 mg per liter, the content of ammonia nitrogen should not exceed 0.02 mg per liter, and the hydrogen sulfide content at the bottom of the pool should not exceed 0.1 mg per liter.

3. The requirement for algae in the pond water is relatively high, and the more suitable water color is the tea brown and yellowish green formed by green algae and diatoms, and the transparency is about 25-40 cm.