CATDOLL : CATDOLL: Crab farming technology and methods, what are the requirements for water quality

1. Crab farming technology and methods, what are the requirements for water quality

1. Build a pond: Build a pond of appropriate size. The height of the pond should be more than 1 meter and the depth of the pond should be about 50 centimeters. 2. Plant aquatic plants: Cultivate aquatic plants in the pond to purify the water quality. The number of plants to be cultivated can be determined according to the season. 3. Prepare facilities: Prepare an aerator and install an anti-escape device. 4. Stock crab seedlings: Select high-quality crab seedlings as the breeding objects and disinfect the pond with quicklime before stocking.

1. Crab farming technology and methods

1. Build a pond

Build a pond of appropriate size, which requires that the pond can receive sufficient light, the pond height needs to be more than 1 meter, the pond water depth should be about 50 centimeters, and the water source must be ensured to be clean and hygienic.

2. Planting aquatic plants

(1) When cultivating aquatic plants in a pond, the amount of aquatic plants can be determined according to the changes in weather and climate. If it is summer, more aquatic plants can be cultivated appropriately. If it is other seasons, the amount of aquatic plants should be reduced.

(2) Aquatic plants can produce oxygen and purify water.

3. Prepare facilities

Prepare an aerator to add oxygen to the water in the pond to prevent crabs from suffocating and dying. At the same time, install anti-escape devices as well as irrigation and drainage systems.

4. Release crab seedlings

(1) Select high-quality crab seedlings for breeding. Crabs with injuries or difficulty breathing should be eliminated in time. Before stocking, disinfect the pond with 70 kg of quicklime per mu.

(2) Half a month after disinfection, let the crab seedlings adapt to the environment in the corner of the pond, and then start to release the crab seedlings. The best time to release them is after the beginning of spring.

(3) After the crabs are released, they should be fed with bait, but the amount should not be too much. Feed them meat after they have grown a little.

5. Breeding management

(1) During the breeding period, the activities of crabs should be observed. If any crabs are found to be moving abnormally, they should be isolated in time.

(2) Change the water frequently. The amount of water changed each time should be about 40%. When adding water, ensure that the water temperature and water level do not change too much.

2. What are the water quality requirements for crab farming?

1. Water quality requirements

(1) The pH value of the pond water is 7.5-8.5, and the dissolved oxygen content exceeds 5 mg/L. If the dissolved oxygen content is lower than 5 mg/L, the growth and development of the crabs will be affected; if the dissolved oxygen content is lower than 2 mg/L, the crabs will die.

(2) The water depth can be maintained at 1-1.2 meters to ensure the freshness of the water quality.

2. Water quality control methods

(1) After the water temperature slowly drops to below 28°C and stabilizes, the water depth can be controlled at 1-1.2 meters, and water should be added and drained once every 3-5 days.

(2) When the water quality is relatively clear, feed normally; when the water quality is relatively concentrated, reduce the amount of feed and change the water in time.

(3) Desilt the pond in a timely manner and plant aquatic plants in the pond.

(4) Use biological agents to regulate water quality and avoid the molting period of crabs.

(5) Sprinkle quicklime throughout the pond and apply calcium dihydrogen phosphate to promote the benign transformation of water substances in the microcirculation and the absorption and utilization of calcium and phosphorus by river crabs when they shed their shells.

2. What are the requirements for pond water quality when breeding crabs?

Water Quality

First of all, they prefer water environments with clear water and high transparency, especially those with a lot of aquatic plants, that is, those with a lot of food. Currently, they are mostly raised in ponds, lakes, and rice fields. We will briefly introduce the common pond farming.

Pond Conditions

Pond farming must first select the right pond conditions. It should have sufficient water sources, good water quality, no pollution, and convenient water inlet and outlet. And the bottom is preferably made of sand and soil with good ventilation, which is conducive to the growth of aquatic plants and can also attract some insects. If you use an old pond, you must do a thorough desilting. In the pond, you should build several small crab islands just above the water surface. On these small islands, it is best to plant some aquatic plants. In addition, the slope of the pond should not be too steep, so that they can climb out of the hole and move around. They like to dig holes, and you can also choose to build artificial caves to accommodate them. Remember to disinfect the pond with quicklime, and wait for half a month after disinfection before you can release the seedlings.

In summer, the weather is extremely hot and the water temperature is also extremely high, which is the biggest problem in crab farming.

The water quality requirements for breeding river crabs are as follows: 1. The dynamic pH value should be about 7.0~8.5, that is, weak alkalinity is required. 2. The dissolved oxygen in the water source should be 5ppm~20ppm, the bottom layer should not be lacking in oxygen, not overoxygenated, and the water body should not be stratified. 3. The ammonia nitrogen value should be below 0.2ppm, and the water should be moderately fertile. 4. No hydrogen sulfide should be detected, and nitrite should be below 0.005. 5. The mineralization degree of nutrient salts should be around 200ppm.

For crab farming, the best water quality indicators are dissolved oxygen > 5 mg/L, hydrogen and nitrogen < 0.1 mg/l, toxic molecular ammonia < 0.1 mg/l, nitrite < 0.05 mg/l), sulfide and hydrogen < 0.1 mg/l, PH 7.5-8.5, and the most important thing is that the total hardness should be between 350-500 ppm. It is recommended that you use the W-Ⅱ Oakdan portable water quality analyzer to test the aquaculture water quality. For specific information, you can search Oakdan's official website on Baidu

3. How to deal with turbid water in the temporary crab rearing pond

In spring, the water in the temporary crab pond is turbid. It is recommended to fertilize the water appropriately, use algae to consume residual bait and feces and other water-damaging factors; feed evenly, and if it doesn't work, replace part of the water. Before releasing river crabs and crab fry, remove the bottom mud and leave about 5cm.

4. How to deal with the green water quality in the swimming crab pond?

The bottom is mainly improved. In the early stage, fertilizers and baits sink to the bottom, so improve the bottom. Kill the algae with large doses and then improve the bottom. Wouldn’t your 2 mu of Bishui’an just promote the growth of algae? ? ?

5. How to deal with crab pond water

During the crab farming process, turbid water is a common problem for farmers. It is more common from April every year, especially after June. It often causes water plants to sink and rot, and the water quality to deteriorate and deteriorate. If not handled in time, it is particularly easy to affect the growth of crabs and even cause death. The main reasons for the turbidity of crab pond water are: 1. Weather factors. Continuous high temperature, sudden heavy rain, haze and sultry weather, etc., lead to convection between the upper and lower layers of water, and a large amount of organic matter at the bottom of the pond is washed to the surface. At the same time, rainwater washes the mud and sand on the edge of the pond into the pond, which will also cause turbid water. 2. Lobsters and wild fish in the pond are not fed enough or are parasitic, causing them to swim irregularly in the pond, causing turbid water. This situation often occurs in old ponds that are not thoroughly cleaned. 3. The environmental factors of the pond are unstable. The water plants are rotting, there are too few water plants, the water is shallow, the moss is dead, and the heavy metals in the water are excessive. In order to find a more comfortable environment, the crabs increase their activity and range, causing the water to become turbid. 4. The crabs themselves are frequently active due to insufficient feeding or diseases, which can also cause turbid water. Corresponding improvement measures should be taken for different causes of turbid water: 1. When the weather is continuously hot and humid, the dissolved oxygen in the water decreases, and the amount of granular oxygen, vitamin C, immune polysaccharides, etc. can be appropriately increased to prevent the crabs from having a stress response. After the weather is clear, spray the entire pond with "strong vitality bacteria" and other microbial preparations to adjust the water quality.