Detailed Practical Techniques for Healthy Grass Shrimp Farming

Grass shrimp, scientific name Penaeus monodon, also known as black shell shrimp, belongs to the family Penaeidae. Because this shrimp prefers to inhabit areas with aquatic plants, it is called grass shrimp. Grass shrimp have the characteristics of fast growth, omnivorous feeding habits, wide salinity tolerance, short farming cycle, large individual size, delicious meat, rich nutrition, and high adult shrimp yield. Therefore, this shrimp has become an important current farming target. The healthy farming techniques are introduced as follows:

1 Shrimp Pond

1.1 Pond Selection

The pond should be built in areas with flat terrain, little silt, abundant water sources, good water quality, no pollution, and convenient water intake and drainage. A mud-sand bottom with an area of 5-8 mu is suitable, with a water depth of 2 m, and each pond equipped with 2-3 units of 2.2 kW aerators. Old ponds should have the sludge and weeds removed or be plowed, and the pond bottom exposed to the sun.

1.2 Pond Clearing and Disinfection

20 days before releasing the seedlings, fill the pond with 15-20 cm of water to soak it, and use a pond-clearing agent to splash the entire pond to kill harmful microorganisms. For some newly excavated ponds and some aged ponds with relatively poor water exchange capacity, in order to prevent harmful algae from breaking out in the middle and late stages of farming, attention should be paid in advance to using algae-removing agents, such as Miezaowang, Bucaozhing and other drugs to kill harmful algae at the bottom of the pond.

1.3 Water Intake Purification, Salinity Adjustment

After the shrimp pond has been cleared, treated and disinfected, water is introduced. When introducing water, it must be filtered through a 60-80 mesh screen to prevent harmful organisms from entering. After the water reaches 80-100 cm, disinfect the water body, using drugs such as Qianglijunduqing to kill viruses in the water. At the same time, use a sprayer to disinfect the pond banks with drugs, appropriately increasing the drug concentration. The pond salinity should match the desalination salinity of the shrimp seedlings in the hatchery.

1.4 Water Fertilization

Using Xiateli has a comprehensive effect. Once Xiateli is added to the pond, diatoms are cultured within 2-3 days. After the basic biological feed has been cultured, release the seedlings only after the water quality meets the following requirements.

1.4.1 Visual inspection: the pond water color has turned yellow-brown or tea-brown, or yellow-green, with a transparency of about 25 cm.

1.4.2 Instrument measurement: use a microscope to observe the microbial density, and use a water quality analysis kit to test various water quality indicators. Release the seedlings after the requirements are met.

.5 Installing Aerators

Paddlewheel aerators have the best effect and should be installed in the deep-water area of the pond. Within one month of seedling release, operate them once each day at noon and before dawn, for 2-3 hours each time. After one month, operate them daily at noon and before dawn, for 3 hours at noon and about 10 hours before dawn. On cloudy and rainy days, increase the operating time and frequency. In the late stage of farming, operate them all day for no less than 20 hours.

2 Shrimp Seedlings

2.1 Selection of Shrimp Seedlings

2.1.1 Principles to master when purchasing grass shrimp seedlings

① Purchase high-health shrimp seedlings (HHS) or shrimp seedlings monitored by a shrimp disease testing center as virus-free.

② Do not use seedlings raised with high-temperature methods or with abusive use of antibiotics.

2.1.2 Shrimp seedlings should be uniform in size. For the same batch of shrimp seedlings, the body length should be 1.0-1.2 cm, the body surface should be clean, vitality should be strong, and those with slender abdominal segments are good seedlings.

2.1.3 Healthy shrimp seedlings have the two small antennae at the front kept together, occasionally separating briefly, but they can immediately close again; those unable to close are relatively poor shrimp seedlings. The tail fan of healthy shrimp seedlings is open.

2.1.4 Healthy shrimp seedlings have "wall-sticking behavior." If you scoop up shrimp seedlings with a spoon, strong shrimp seedlings will quickly swim toward the edge of the spoon and cling tightly to the spoon wall without moving. If they swim around randomly in the water, they are unhealthy shrimp seedlings.

2.1.5 Take out several shrimp seedlings about 1 cm in body length from the nursery pond, wrap them in a wet towel for 5 minutes, then take them out and return them to the original water. If there is no effect on the survival rate, they are high-quality shrimp seedlings.

2.2 Stocking of Shrimp Seedlings

2.2.1 Before releasing the seedlings, the water body must undergo disinfection treatment, striving to keep both the water environment of the shrimp seedlings in the nursery and the water environment of the farming pond within safe ranges. In addition, pay attention to the water testing step before stocking. After 1-2 days of water testing, if the pond water environment has no effect on the survival rate of the shrimp seedlings, the seedlings can be released in batches.

2.2.2 Precautions for releasing seedlings:

① Choose the leeward side of the shrimp pond as the release site. Never release seedlings against the wind or in shallow water.

② Do not release seedlings in bad weather. Choose 8-9 o'clock in the morning on a sunny day or when the sun sets in the afternoon to release seedlings. Do not release seedlings at noon.

③ Do not rush to release seedlings if pond clearing and pest elimination are not thorough.

④ Do not release seedlings if the water color and water quality of the shrimp pond are poor.

2.3 Stocking Density

The seedling release density should be between 8,000-12,000 tails/mu. Because pond conditions vary, the amount of seedlings released can be increased or decreased according to actual conditions.

3 Management During the Grow-out Period

"@#@234@#@ is all about cultivating water" has become a saying based on the experience of many shrimp farmers. Maintain excellent water quality to facilitate shrimp feeding and promote shrimp molting and growth.

3.1 Water Quality

The optimal range of water quality for grass shrimp grow-out ponds is shown in the table below

Measurement Item Suitable Range Poor

PH 8-9 Below 7.5 or above 9.5

Dissolved oxygen (7-10)×10-6 Below 3×10-6 or 12×10-6

Salinity 0.015-0.025 Below 0.010 or above 0.035

Non-ionic ammonia (NH3-N) (0.1-0.5)×10-6 Above 0.6×10-6