Techniques for Pure Freshwater Farming of Whiteleg Shrimp

AbstractStocking shrimp larvae: Select shrimp larvae that are highly active, strong in adapting to water, with a transparent body, no blackening on the gills, and with the black umbrella fully open, and stock them in a pond with a water temperature above 20°C. Strict desalination and nursery rearing: In the early stage of farming, the shrimp larvae must be gradually desalinated and reared, that is, desalination and nursery rearing. Water quality requirements: The fluctuation range of the pond water salinity should not exceed 5%, the pH value should be around 7.5-9.0, and the daily fluctuation range should not exceed 0.5 units, etc.

I. Stocking shrimp larvae

1. The survival water temperature for whiteleg shrimp is around 15-25°C, and the optimal growth water temperature is 28-32°C. When shrimp are farmed at this water temperature, their growth rate is relatively fast and their constitution is robust.

2. The water temperature for stocking shrimp is required to be above 20°C. Stocking can be carried out in the evening or on a sunny day. Be sure not to release the larvae at noon under direct sunlight or in rainy weather when the water is turbid.

3. In the Huanggang area, larvae are generally released around the end of May, when the water temperature is basically stable at around 25°C. Releasing larvae within this water temperature range can prevent low-temperature stimulation caused by cold currents.

4. When releasing the larvae, first place the packaging bags containing the shrimp larvae into the pond for about 30 minutes, so that the water temperature inside the bags is consistent with the pond water temperature.

5. When selecting shrimp larvae, the larvae are required to be highly active, strong in adapting to water, with a transparent body, and must not lack red color, with no blackening on the gills, and the black umbrella needs to be fully open.

II. Strict desalination and nursery rearing

1. Hatcheries usually hatch and breed shrimp larvae in seawater with a salinity above 20‰. Although they have undergone a short period of desalination treatment, direct stocking will lead to a low farming survival rate, or even total death, so in the early stage of farming the shrimp larvae must be gradually desalinated and reared.

2. First carry out desalination and nursery rearing. Before releasing the larvae, first use an earth dam or colored strip cloth to enclose a temporary rearing pond in one corner of the pond, with a stocking quantity of 500-1000 tails per square meter. At the same time, add coarse salt and sea water essence to the temporary rearing pond to adjust the salinity to approximately the same as that of the hatchery.

3. When releasing the larvae, adjust the pH value to 7.8-8.6, the water temperature should not differ by more than 3°C, and the salinity should not differ by more than 3‰-5‰.

4. Four days after releasing the larvae, 3-5 cm of pond water can be added each day, so that the salinity of the water in the temporary rearing pond gradually decreases. At the same time, the pond water should always be maintained at a depth of about 1 m, and attention must be paid to adjusting the water color and pH value.

5. After the larvae are placed in the temporary rearing pond, feeding should begin that evening, and after 4 days they can be directly fed shrimp feed. For the first time, the feeding amount per 10,000 tails is 5-10 grams, fed about 5-6 times per day, with the daily feeding amount increased by 20-30%.

6. Wait until the shrimp larvae grow to more than 2 cm, then feeding can be stopped. At the same time, dig several gaps in the dam of the temporary rearing pond to connect it with the farming pond, so that the shrimp larvae can freely swim out of the temporary rearing pond. With a reasonable farming density of about 100,000 per mu, about 100,000 tails per mu can be achieved.

III. Water quality requirements

1. Whiteleg shrimp is a marine shrimp, so the fluctuation range of the pond water salinity in the farming pond should not exceed 5%, the pH value should be around 7.5-9.0, and the daily fluctuation range should also not exceed 0.5 units.

2. Its dissolved content is above 4 mg per liter, the nitrite nitrogen content should not exceed 0.1 mg per liter, the ammonia nitrogen content should not exceed 0.02 mg per liter, and the hydrogen sulfide content in the bottom layer of the pond should not exceed 0.1 mg per liter.

3. There are relatively high requirements for the algae in the pond water. The more suitable water color is the tea-brown or yellow-green formed by green algae and diatoms, with a transparency of about 25-40 cm.