What Aquatic Plants Are Good to Plant for Crayfish Farming in Ponds? Planting Time and Methods

Among crayfish farmers there is a saying——“Whether the crayfish are good depends on whether there is grass in the pond; whether the crayfish are big depends on the grass in the pond”, which speaks to the importance of aquatic plants in crayfish farming. Sowhat aquatic plants are good to plant for crayfish farming in ponds? When should they be planted? What are the aquatic plant cultivation methods?

I. When should aquatic plants be planted for crayfish farming?

Basically, it is best to plant the aquatic plants before releasing the crayfish fry, as this is conducive to the survival and growth of the crayfish.

However, it should be noted that the success rate of crayfish farming during the high-temperature period (mainly referring to summer and autumn, June-September) is very low. The main reason most crayfish cannot be successfully farmed during this period is that aquatic plants have not been established in the shrimp pond, and there is no other option but to substitute inferior aquatic plants such as alligator weed and water hyacinth, ultimately resulting in very poor crayfish yields. Judging from the experience of the few farmers who have succeeded in farming shrimp during the high-temperature period, aquatic plants remain the main factor restricting crayfish yields. The most ideal aquatic plant for summer and autumn is Hydrilla verticillata, commonly known as “denglong paozi” (lantern bubble).

II. What aquatic plants are good to plant for crayfish farming in ponds?

1. Why should aquatic plants be planted for crayfish farming?

(1) Enriching feed

Crayfish have very omnivorous feeding habits, mainly feeding on animal matter, but aquatic plants are fresh and tasty and rich in nutrients, and crayfish are very fond of them too, making them a supplement and regulator to animal feed.

Aquatic plants can create a good ecological environment. Wherever there are many species of aquatic plants growing densely, small fish, small shrimp, shellfish and other benthic animals are also relatively abundant, so planting aquatic plants can increase the animal bait in crayfish fields.

(2) Improving water quality

Aquatic plants can carry out photosynthesis, increasing the dissolved oxygen content in the water, absorbing nutrients from the water body, reducing water fertility, maintaining fresh water quality, and stabilizing pH, thereby providing crayfish with a water environment of good quality and rich dissolved oxygen for their growth and development.

(3) Promoting crayfish growth

Aquatic plants are an ideal habitat for crayfish, facilitating their climbing and providing support for their activities. Due to the concealment provided by aquatic plants, they can provide a good place for shrimp to molt and help crayfish avoid predators. During hot seasons, aquatic plants can provide shade and lower temperatures, making them a good place for crayfish to cool off and escape the heat. In addition, aquatic plants have special pharmacological effects that can reduce the incidence of disease. In fields or ponds with abundant aquatic plants, the survival rate of crayfish is high; aquatic plants can improve both the internal and external quality of crayfish.

2. Main aquatic plant varieties

The aquatic plants planted in crayfish farming ponds mainly fall into three categories: submerged plants, floating plants, and emergent plants. Generally, submerged plants and floating plants are the main ones planted, with emergent plants as a supplement.

(1) The main varieties of submerged plants include: Elodea (Elodea canadensis), tape grass (Vallisneria), curly pondweed (Potamogeton crispus), Potamogeton malaianus, hornwort (Ceratophyllum demersum), etc.;

(2) The main varieties of floating plants include: alligator weed (Alternanthera philoxeroides), water hyacinth (Eichhornia crassipes), water lettuce (Pistia stratiotes), duckweed (Lemna), etc.;

(3) The main varieties of emergent plants include: reed (Phragmites), wild rice stem (Zizania latifolia), arrowhead (Sagittaria sagittifolia), cattail (Typha), etc.

Note: The aquatic plant varieties planted in crayfish farming ponds must be a mix of multiple species.

III. Planting methods for aquatic plants in crayfish farming

1. Stem-cutting method

Stemmed aquatic plants such as Hydrilla verticillata and Elodea are suitable for the stem-cutting method, generally planted in winter and spring. The method is to cut the aquatic plants into small segments 15-20 cm long, and like transplanting rice seedlings, insert bundles of the cut stem segments evenly into the mud at the bottom of the pond, with plant and row spacing controlled at about 20 cm each. After planting, fill the shrimp pond with 20-30 cm of water, and gradually deepen the water level after the aquatic plants have covered the entire pond.

2. Broadcasting method

Floating-leaf plants such as water chestnut (Trapa) and water lily (Nymphaea) can be wrapped tightly in soft mud and directly broadcast into the pond, so that their roots and stems grow in the bottom mud and their leaves float on the water surface.

3. Transplanting method

Emergent plants such as wild rice stem and arrowhead should be transplanted with roots. When transplanting, damaged leaves and thin, inferior seedlings should be removed. The transplanting location can be in the shallow areas at the edge of the pond. The roots of the seedlings should be submerged 10-20 cm in the water, and the density should be controlled at 30-50 plants per 667 sq m.

4. Cultivation method

For floating plants such as alligator weed, water hyacinth, and duckweed, a corner can be enclosed in the pond with bamboo poles, grass ropes, etc., as a cultivation “special zone” for intensive cultivation, allowing the above aquatic plants to grow and reproduce in the “special zone” environment, as a supplement when there are insufficient aquatic plants in the shrimp pond.

5. Seeding method

The most commonly used aquatic plant is generally tape grass (Vallisneria). Tape grass uses the seeding method, suitable for shrimp ponds with relatively little mud. First soak the tape grass seeds in water for 1 day, then rub the softened fruit apart, extract the tiny seeds from the fruit, add about 10 times the seed volume of fine sandy soil, mix well with the seeds, and then sow. When sowing, control the water level at 10-20 cm, and the seeding rate at about 50 grams per 667 sq m. After sowing, strengthen management to improve the survival rate of tape grass and enable it to form a dominant population as quickly as possible.