What role do aquatic plants play in river crab farming? A full analysis of the precautions

In recent years, more and more people have started taking up river crab farming. Planting aquatic plants is a key factor in the success of river crab farming. Aquatic plants are not only an indispensable plant-based feed for river crabs, but also an important place for shrimp and crabs to inhabit, feed, molt and evade predators. So what role do aquatic plants play in river crab farming? What are the precautions? Let us take a look together.

1. What role do aquatic plants play in river crab farming?

The so-called “good grass” refers to submerged plants such as Elodea (Canadian waterweed), Hydrilla verticillata and Vallisneria (tape grass) used in healthy river crab farming. The aquatic plant coverage of the whole pond should be controlled at 50%-60%. As far as submerged plants are concerned, healthy river crab farming has multiple benefits.

1. The grass is crisp, tender and palatable, rich in nutrients, and is a natural feed for river crabs.

2. It has strong reproductive and regenerative capacity; it can not only purify water quality but also improve the substrate, creating good environmental conditions for river crab growth.

3. It can provide an ideal place for river crabs to hide, inhabit and molt.

4. Submerged plants carry out photosynthesis in the water, which can increase the dissolved oxygen content of the water body, absorb ammonia nitrogen and inorganic nutrient salts in the water, and increase water transparency.

5. It can play a role in slope protection and prevent pond embankments from collapsing.

6. It can improve the quality and value of river crabs. River crabs grown in waters with fresh water quality, high dissolved oxygen, clumps of aquatic plants and abundant feed have bright color and large size, and their taste and price are close to those of natural river crabs, thus achieving the goal of increasing production and income in farming.

7. It has a certain pharmacological effect.

2. Precautions for aquatic plant management in river crab farming

1. Scientifically control the density of aquatic plants and cut excess aquatic plants in time

The growth process of aquatic plants in a pond is a process of absorbing harmful substances from the water body, and then the pond as a carrier also has a load limit for the aquatic plants. Once the amount of aquatic plants exceeds this load limit, the oxygen produced by the plants through photosynthesis during the day cannot meet the oxygen consumption of the plants themselves at night, and the aquatic plants will age and die. The principle of mowing grass is to cut away aged aquatic plants and promote the growth of new aquatic plants. In short, keep the proportion of aquatic plants in the pond no more than 30%, and there should be waterways in the middle of the aquatic plant areas, with the waterway width maintained at about 2 m.

2. Muddy grass is a reflection of water body aging

The appearance of muddy grass is generally due to aging of the water body, with excessive organic matter attached to the aquatic plants. It is also very simple to deal with. First, use sodium humate to remove the mud from the aquatic plants and activate the aquatic plants to grow again, then use microbial preparations to regulate water quality, reduce organic matter in the water body, and improve the algae phase of the water body. At the same time, use biological substrate improvement drugs to decompose organic matter in the mud, tackling the problem from three aspects at once. At the same time, also pay attention to the phenomenon of aquatic plants floating up after being clipped. Excessive clipping and floating indicates insufficient or unpalatable feeding of bait; combine water quality testing and analysis to prescribe the right remedy.

3. Do not stock herbivorous fish and do not use aquatic plant inhibiting drugs

Some herbivorous fish can indeed consume excess aquatic plants, but the growth of aquatic plants and herbivorous fish often cannot be controlled by farmers, which is an unsafe factor. The vast majority of farmers no longer stock herbivorous fish, and aquatic plant inhibiting drugs usually also interfere with algae in the water body, easily causing poor water quality and oxygen deficiency. At the same time, they also have toxic effects on river crabs and freshwater shrimp that molt among the aquatic plants.