What are the precautions for raising crabs in a new pond?
Because a new pond has just been built, there are still many precautions to note when using it to raise crabs. Below we will introduce them to you.
In a new pond, appropriately plant alligator weed. Doing so not only provides food for the crabs, but also helps purify the water quality, prevent crab diseases, provide shade, and offer hiding places for crabs to molt.
Alligator weed, also known as alligatorweed, is an excellent aquatic green feed for livestock, poultry, and fish. When planting alligator weed in a new pond, its area must not exceed 20% of the new pond's area, and it should be planted in blocks and patches in the new pond, all floating on the water surface of the new pond.
After planting alligator weed in a new pond, the crabs can frequently feed on the root tendrils and some leaves of the alligator weed, as well as the filamentous algae, diatoms, and other algae attached to the alligator weed, and small animals such as bell animalcules, Zoothamnium, and rotifers. At the same time, alligator weed can attract aquatic oligochaetes, small fish, small shrimp, and aquatic insects. In this way, it enriches the crabs' feed and can reduce feeding costs.
Planting alligator weed in a new pond can also play a role in absorbing nutrients, making the water quality in the new pond leaner and purifying it, thereby overcoming the problem of the new pond's water quality becoming fertile due to the large amount of waste excreted by the crabs, reducing the occurrence of crab diseases and benefiting the normal growth of the crabs.
Apply sufficient base fertilizer, and skillfully apply topdressing
Applying a sufficient amount of base fertilizer can increase the fertility of the pond water body, promote the reproduction of plankton, and provide sufficient natural bait for crab seedlings; increased fertility can also satisfy the growth of aquatic plants and provide a good habitat environment for crab seedlings. The base fertilizer should mainly be chicken, cattle, and other poultry and livestock manure. Before use, it should be piled and fermented for 15 days and applied sufficiently several days before disinfection, with a base fertilizer amount of 300 kg per mu. In addition to feeding enough feed, crab species still need frequent fertilization so that the amount of plankton in the pond water body increases. Flexibly control the amount of fertilization according to specific conditions such as weather, water quality, and water temperature, so that the pond water appears tea-brown, oil-green, or sauce-red, with transparency maintained at 30-40 cm. Throughout the entire breeding process, the water quality should always remain fertile, lively, tender, and refreshing.
Clear the pond and disinfect, improve the bottom substrate
After the base fertilizer is applied, promptly use quicklime to thoroughly disinfect the pond. Many farmers think it is a new pond and omit disinfection. The author believes that even a new pond may contain some pathogens, and using quicklime for disinfection can improve the bottom substrate and supplement calcium to meet the growth needs of crab species. Generally, dry-pond sprinkling of quicklime is used for disinfection, with an amount of 75 kg per mu.
Plant aquatic plants, and strictly manage and protect them
Because there are no old aquatic plant rhizomes in the new pond, all need to be transplanted from outside. In order to ensure a pond of good aquatic plants is maintained in the middle and late stages of breeding, adopt the planting method to increase the growth and reproduction speed of aquatic plants. When planting, control the row spacing at 1.5 m and keep the plant spacing at 0.7 m. The planting amount per plant is 1 kg. After planting, cover with soil to prevent the alligator weed from floating due to water buoyancy after water enters. The planting method can save the amount of aquatic plants used and also ensure the quantity of aquatic plants.