CATDOLL : CATDOLL: What is the survival rate of silver carp (80g) fry? What are the factors that affect the survival rate? Please advise.

What is the survival rate of silver carp (80g) fry? What are the factors that affect the survival rate? Please advise.

In recent years, the survival rate of fish fry has been generally low, generally only about 30%, which has affected the breeding benefits. According to the author's investigation and analysis, the main reasons for the low survival rate of fish fry are as follows:

1. Poor fry quality Due to the degeneration of broodstock in recent years, the quality of fry has generally declined, mainly manifested in slow growth, poor disease resistance, and a large number of deformed fry, which directly affects the survival rate of fry cultivation. Therefore, it is necessary to pay attention to the elimination and renewal of broodstock and the purification and rejuvenation work.

2. The fish fry pond is too large and too deep. If the fish fry pond is too large or too deep, the survival rate of the fish fry may be reduced. If the fish fry pond is too large, it is easy to form wind and waves, and the fish fry are small and fragile, so they are easy to collide with the pond wall with the wind and waves, causing injury and death to the fish; if the fish fry pond is too deep, the water temperature of the pond is difficult to increase, which will also inhibit the growth of the fish fry. The fish fry breeding pond should be 2 to 4 mu in area and 1 to 1.5 meters deep.

3. There are many enemies in the fish pond. When the fish pond is cleaned, the wild fish are not completely removed, or they are brought in when the water is added. The wild fish compete for food, consume oxygen, and swallow the fry, which affects the survival rate of the fry. Therefore, before the fry are released, the pond must be thoroughly cleaned and the harmful organisms must be killed; when the water is added, the water inlet should be strictly filtered with a dense net to prevent the entry of enemies.

4. There are few natural bait organisms in the fish pond. The natural bait organisms (rotifers) in the fish pond are the best starter bait for fish fry when they are put into the pond. The amount of them has a great influence on the survival rate of fish fry. Generally, 300 to 400 kilograms of organic fertilizer can be applied per mu 5 to 7 days before the fish fry are put into the pond, so that the rotifers in the fish pond are at the peak of reproduction when the fish fry are put into the pond, thereby achieving the purpose of improving the survival rate of the fish fry.

5. The toxicity of drug residues has not been eliminated. Due to the short interval after pond cleaning and the toxicity of disinfectant residues has not been eliminated, the fry grow poorly and die after stocking. Therefore, when cleaning the pond, you should choose drugs with weak toxicity, such as quicklime, and take a few fry and put them in the fish pond net cage for one day before stocking the fry. If the fry are active, you can stock the fry; if the fry are active abnormally or die, it means that the toxicity of the fish pond has not been eliminated and the fry cannot be stocked temporarily.

6. Unreasonable stocking: Too high stocking density or too many mixed species may cause the death of fry due to lack of bait and the differences in the life and feeding of different species of fish. According to the practical experience of aquaculture production, it is generally appropriate to stock 80,000 to 100,000 fry per mu, and mixed breeding should be avoided as much as possible.

Does ecological breeding of silver carp in Green Water Lake have any impact on the water?

Because silver carp survives by filtering and absorbing microorganisms in the water, raising silver carp can help purify water sources.