CATDOLL : CATDOLL: How can young crabs be bred and managed scientifically?

River crabs are one of the aquaculture species that have developed in recent years. Many farmers raise crabs according to traditional fish farming experience, but the yield is not high. In addition, the market price is not high and the disease is serious, which makes many farmers lose money year after year. The author talks about some superficial views on the scientific breeding and management of common river crabs in current production practice, which can be used as a reference for farmers in actual production.

1. Grading and breeding

After long-distance transportation, the young crabs are released into the ponds. The first molting damage is relatively serious (this situation does not exist for the young crabs cultivated locally). In order to facilitate management, the young crabs must be raised in grades. The graded raising can be carried out in a "回"-shaped mother-child pond or a "日"-shaped series pond. The stocking density is 2,000 to 5,000 per mu. The graded stocking conforms to the growth law of river crabs and is convenient for the feeding and management of young crabs. During the young crab cultivation period, it is convenient for the growth of aquatic plants in the adult crab pond; in addition, it is convenient for "counting" after May. During the secondary rearing, seedlings can be supplemented in time (after "counting" in the primary culture pond with a ground cage, they are placed in the adult crab breeding pond. Generally, the secondary stocking density is between 500 and 800 per mu). Otherwise, it is difficult to master the early survival rate of young crabs cultivated in large ponds, and their economic benefits are often affected by insufficient seedlings.

2. Scientific feeding

The food intake of young crabs is significantly higher than that of crab seedlings, and the feed range is also relatively wide. The ratio of animal and plant feeds is preferably 1:2 to 2:3. It is recommended to use complete granular feed. A single feed is prone to nutritional deficiency due to incomplete nutrition. On the other hand, it is easy to pollute the water quality and cause diseases. The feeding amount is 5-10% of the crab's body weight. It should be increased or decreased in time according to the eating situation. Feeding is mainly done in the evening. When feeding, it should be spread at fixed points along the shallows around the pond. If a large number of crabs are found to be molting, they should be fed away from the grass or the crab molting belt to avoid crabs killing each other.

3. Daily Management

In the first-level cultivation pond, since the water plants have not grown well, you can go to the inland river or lake area to salvage the newly green water plants and put them into the pond, and put snails in appropriate amounts to supplement the natural cheap feed of river crabs. However, both water plants and snails must be disinfected before being put in to prevent bacteria or harmful substances from entering the cultivation pond. During the juvenile crab period, the water level should be shallow, maintained at 30-50 cm. Too deep water level will cause high water pressure, which is not conducive to the growth and molting of juvenile crabs. The pH value of the juvenile crab cultivation pond should be between 7.5 and 8.5. The juvenile crab feed should be nutritious and it is best to feed full-price granular feed. If it is artificial compound feed, antibiotics, decapping agents, calcium dihydrogen phosphate and other substances should be regularly supplemented to meet the growth needs of river crabs. Patrol the crab pond several times a day, observe the habitat and feeding conditions of river crabs, check the escape prevention facilities, and repair them in time to prevent river crabs from escaping if there are problems. Regularly measure the water quality and improve the water quality. Take strict precautions against sudden weather changes. In short, the healthy breeding of river crabs must have: a foundation, that is, a good breeding water environment; three elements, that is, water, species, and bait; and a core, that is, scientific management technology. Only by achieving the above points can the healthy growth of river crabs be guaranteed and the economic benefits of the majority of breeders be increased.

Grading and breeding. After long-distance transportation, young crabs are released into ponds. The damage caused by the first molting is relatively serious. For the convenience of management, young crabs must be raised in grades. Grading breeding can be carried out in a "回"-shaped mother-child pond or a "日"-shaped series pond. The food intake of young crabs is significantly higher than that of crab seedlings, and the range of feed is also relatively wide. The ratio of animal and plant feeds is preferably 1:2 to 2:3. It is recommended to use full-price compound granular feed. In the first-level breeding pond, since the aquatic plants have not grown well yet, you can go to the inland rivers or lakes to salvage the newly green aquatic plants and put them into the pond, and put snails in an appropriate amount to supplement the natural and cheap feed of river crabs. However, both aquatic plants and snails must be disinfected before being put in to prevent bacteria or harmful substances from entering the breeding pond.

1. Grading and stocking: After long-distance transportation, young crabs are released into ponds, and the damage from the first molting is relatively serious (this situation does not exist for locally cultivated young crabs). In order to facilitate management, the young crabs must be graded and raised. Gradual raising can be carried out in a "U"-shaped mother-and-child pond or a "日"-shaped series pond.

2. Scientific feeding: The food intake of young crabs is significantly higher than that of crab seedlings, and the range of feed is also wider. The ratio of animal and plant feeds should be 1:2 to 2:3. It is recommended to make the feed into granular compound feed or use full-price compound granular feed.

You need to pay attention to the environment, temperature, choose suitable varieties for breeding, and ensure a certain level of cleanliness and hygiene.