1. Not clear pond or clear pond is not complete. In the area of ​​Clear Pond, some professional households do not understand the importance of clear ponds. In order to save the cost of clear ponds or clear ponds, the main manifestations are: Some think that ponds have been exposed to sunlight (short-term, no tripping of the sediment) Completely kill the enemy and the source of the disease; some believe that as long as the foot just lime (powder or a small amount of block) clear pond can be. This is a misunderstanding of two kinds of clear ponds that are common among farmers. Therefore, in the future, it is necessary to strengthen the publicity and guidance for professional households in Qingtang, and effectively raise the awareness of professional households about the importance of clear ponds, as well as the use of clear lime ponds for their usage and usage.

2. From the time of clear ponds to pre-stocking, the enemy organisms are re-entered into the pond and their control is not strict. Most technicians and professional households do not have enough knowledge of re-entering the ponds from the time they go to clear water ponds before restocking. For example, there is no dense network at the injection and drainage outlets; In the north, from April to May, it is the time that the fishes are under the pond. It is also the time for the frogs to multiply and spawn. Due to the limited natural water, the frogs choose to pond for spawning. Clearing will cause great damage to the fry.

3. The time of fry ponds and the maximum time of planktonic biomass in the pond are inconsistent. Since air transportation is greatly affected by the weather, it is often impossible to arrive at the scheduled time. Therefore, it is very difficult for specialized households to grasp the pond water body during the fertilization time, which may result in the biological shortage or the increase of harmful organisms in the rear of the fish pond. Therefore, the combination of plankton cultivation and palatable artificial bait feeding should be adopted before and after the fry.

4. Feeding bait is not nutritionally adequate and is fed extensively. For many years, many professional households have followed the feeding method of “a handful of bran”, which is troublesome: instead of using egg yolk and soymilk, feeding in the course of feeding is not strictly in accordance with “Four Ding”, which can easily cause fry constitution. Weakness, indigestion.

5. Do not pay attention to the damage caused by the “cold winter” to the fry. The “cold spring” occurs frequently from April to May behind the northern fry pond. Many professional households do not pay enough attention to it. They still follow the textbook knowledge and put it to death. The water depth of the fish pond is 30-40 cm. Adjustment, so that the water temperature can easily be subject to dramatic fluctuations in temperature and fluctuate greatly, causing frozen fish fry. Therefore, the depth of fish ponds in the North should be deepened to 0.6-1.0 m as appropriate.

6. The fry cultivation will be polycultured in adult fish mode. The cultivation of fry is different from adult fish. In the case of polyculture, due to differences in breeds, feeding habits, and ability to fight for food, it is bound to cause fragility and death of fry without strong competition. Therefore, monoculture should be adopted.

7. The stocking density is irrational. Some of them have a large stocking density and a small pond area, while others have a large pond area and a small stocking density. These two abnormalities can often be seen in the cultivation of northern fry. Large stocking densities and small pond areas are prone to high-temperature seasonal deficiencies such as varying sizes and sizes; ponds with large ponds and small stocking densities tend to result in increased management difficulties and inequalities in fry feeding. Correct it.

8. Do not pay attention to pull network exercise. Pulling nets during fry cultivation and before splitting the pond is an important measure to enhance the fish's constitution and oxygen tolerance. If you give up the net exercise, the fry's physique and oxygen tolerance will not increase, and the survival rate will be greatly reduced.

9. Do not pay attention to grading and separation. Some professional households in the entire fry cultivation process, the fish is not grading, regardless of ponds, to take a way to raise the end, greatly reducing the survival rate of fish fry and yield.

10. Do not top-dress during cultivation. Fertilizing is another important measure in fry cultivation. It is an important means for continuation and maintenance of plankton totals in ponds. Many professional households do not pay attention to this, which can easily lead to the lack of natural foods during and after the cultivation of negative seedlings.

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