What conditions are needed for raising giant river prawns?

SummaryA giant river prawn (Macrobrachium rosenbergii) farm needs to be built on flat terrain with convenient power supply. The suitable width of a prawn pond is 40-60 m, the water depth is about 1.5 m, and feeding platforms with a width of no less than 2 m need to be built. Loam and clay can be chosen as the farming soil, and unpolluted lake water and river water are used as the water source. The dissolved oxygen content in the pond needs to be maintained at 3-5 mg/L, the pH at 7-8.5, and the water temperature at about 25-30°C. During this period, auxiliary facilities need to be well equipped.

I. Geographical location and soil quality

1. Geographical location

The prawn farm needs to be built in a place with relatively stable terrain changes, flat terrain, sufficient water source, suitable water quality, and convenient power supply.

2. Soil quality

The soil of prawn ponds is best mainly loam and clay, and sandy soil should not be used, because clayey soil is prone to hardening, has relatively poor aeration, and is not easy to seep and leak water. Prawn ponds with this kind of soil have good water retention, and the nutrient salts in the water are not easy to seep and be lost, which is beneficial to the reproduction and growth of bait organisms in the water, and can also maintain the fertility of the pond water and promote the growth and development of giant river prawns. Sandy soil, however, is prone to seepage, leakage, and collapse, so it is not conducive to the normal growth of giant river prawns.

II. Water source and water quality

1. Water source

Giant river prawns have relatively high requirements for water, so unpolluted lake water and river water need to be selected as the water source, because this kind of water is rich in dissolved oxygen and the water quality is relatively fertile, which is very suitable for the robust growth of giant river prawns and also meets the requirements for high-density giant river prawn farming. To prevent harm to giant river prawns caused by industrial wastewater, domestic sewage, and harmful pesticide water from rice fields, when building a prawn farm, it is necessary to have a full understanding of the surrounding water source environment.

2. Water quality

For the water quality indicators of high-yield prawn ponds, the dissolved oxygen content is required to be maintained at 3-5 mg/L or above, the pH at 7-8.5, and it needs to remain weakly alkaline. The total hardness should be less than 100 mg/L. In brackish water with a salinity below 12%, giant river prawns can grow and develop normally, but they cannot tolerate low temperatures below 14°C. The suitable water temperature for growth is 25-30°C. The content of heavy metal ions such as copper, mercury, and zinc needs to comply with the nationally stipulated water quality standards for fishery waters.

III. Prawn pond structure

1. Shape

Prawn ponds can be built in a rectangular shape, longer east-west and wider north-south, with a length-to-width ratio of about (4-6):1, and according to the terrain, prawn pond specifications, and prawn farm layout, the suitable width is generally 40-60 m.

2. Area

If the pond construction area is relatively small, it will lead to unstable water quality, while if the construction area is too large, it will be unfavorable for production operations and management. Therefore, a single prawn farming pond is preferably 3-5 mu. If it is a prawn-based mixed prawn-fish pond, 8-10 mu is preferable. Such a construction area is conducive to enhancing the dissolved oxygen in the pond water and can also maintain a stable water environment.

3. Water depth

The water depth of the prawn pond can be about 1.5 m. The pond ridge needs to have a certain slope. There should be a prawn collection ditch in the center of the prawn pond. Higher aquatic plants, benthic animals, epiphytic algae, and so on can grow in the pond. These species can regulate water quality and can also serve as bait and hiding places for prawns.

4. Feeding platform

Intensive prawn ponds mainly rely on artificial feeding of feed, so building feeding platforms is essential. A pond edge with a relatively long beach foot can be selected, and at 40-80 cm below the water surface, a feeding platform with a width of no less than 2 m can be built for giant river prawns to feed.

IV. Auxiliary facilities

Auxiliary facilities include water pumps, aerators, vehicles, cold storage, power facility support, and high- and low-voltage lines. Usually, 8 kilowatts of power is equipped per hectare, as well as warehouses used for storing raw materials, feed, and nets. Usually, a 150-mu prawn farm needs to build one warehouse with a capacity of 20 tons.