Cage farming for crab is popular aquaculture in large water. The biggest factors crab culture is to meet needs for dissolved oxygen and fresh water.
1. Water environment
The water should be slightly alkaline. The pH value should be from 7.5 to 8.5. Oxygen dissolved in water should be about 5 mg/liter. The aquatic plants should take up at least 1/3.
2. Fish cage
- The cage should be set up in low-speed water regions.
- The net should be made of polyethylene mesh. The size of the cage is usually 4 meters by 2 meters. Mesh size should be 0.5 to 1.5 millimeters to prevent crab from escaping.
- The stocking density is based on the management and the crab. Generally, it is 10000~20000 units per cubic meter.
- Regularly check and brush the net cage. It can avoid mesh from blocking. Otherwise, it might block water exchange and lead to insufficient oxygen.
3. Technical bullet points
- Water depth
The average water should be 2 meters in depth.
- Mesh specification
Generally, the cage is usually made of polyethylene or nylon. The net mesh is 1.5 centimeters. The cage with a cover net is preferred for large culture.
- Culture density
It should be 100~160 units per square meter. People can culture crab with silver carp and bighead at the same time. These two can be put into the cage 10~15 days after the crab.
Plant baits could be bean cake, corn, wheat, potato and so on. Animal baits could be snails, mussel, small fish and so on. The pure protein should be above 30%. The baits should be floating in the water for at least 24 hours. The feed coefficient should be about 2.
- Daily management
Quicklime can be used to improve water calcium. It can reinforce crab shell, kill pathogens and increase the pH value at the same time. Also, clean residual bait in time. Find out and repair the damaged cage immediately. Dead crabs should be picked up in time so these will not infect the healthy.
This is the end of the topic. What do you think of cage farming for crab? Leave your comments!