Causes of death of farmed tadpoles

Tadpoles are the larvae of frogs and toads. The newly hatched tadpoles have a spindle-shaped body without four limbs, mouth and inner gills, with a long flattened tail and branched outer gills on both sides of the head, which are absorbed on aquatic plants and nourished by the remaining yolk in the body. So, what are the causes of death of farmed tadpoles?

I. causes of death of farmed tadpoles

1. Germplasm degradation of parent frog

The germplasm degradation of parent frogs will affect not only reproduction, but also fertilization rate, hatching rate and survival rate of tadpoles and young frogs. The investigation found that a large number of deaths of Tsai Meng were also directly related to the germplasm degradation of the parent frog.

2. The influence of ecological factors

The decrease of dissolved oxygen during hatching is one of the important reasons for the death of young tadpoles. The hatching of eggs needs to consume oxygen, and the hatched tadpoles consume a large amount of oxygen, coupled with the differentiation of egg membrane during hatching and the corruption of attachments such as aquatic plants that enter the hatching pool with the eggs. According to the study, when the amount of dissolved oxygen in the hatchery falls below 3 mg / L, the young tadpoles will float. As a result of the young tadpole's delicate constitution, once the floating head can not be rescued, resulting in death. In addition, temperature is also one of the important factors causing the death of young tadpoles. The optimum temperature of young tadpoles is 20-30 ℃, and the optimum water temperature is 25-3 ℃. Because of the large temperature difference between day and night, the temperature of the young tadpoles propagated in early summer dropped below 20 ℃ at night, while the young tadpoles bred in July and August were at high temperature in midsummer, and the daytime temperature was often as high as 35 ℃. The young tadpoles bred in these two periods often die in large numbers. In addition, polluted water can also cause the death of tadpoles.

3. Getting out of the pool too late

Newly hatched tadpoles should generally wait for a period of time before being fished out of the pond, and the exact time should be determined according to the development of internal organs and external environmental conditions. Generally speaking, tadpoles have to leave the pool 6-7 days after hatching, because the tadpoles have changed from internal nutrition to external nutrition, and they are in urgent need of feeding, and as the individual grows up, the oxygen consumption increases. Missed the favorable opportunity to get out of the pool, often due to hypoxia and lack of nutrition, resulting in the death of a large number of tadpoles.

In view of the causes of the death of a large number of tadpoles, corresponding management measures should be taken, such as meeting the necessary ecological conditions and correctly grasping the time of tadpoles leaving the pool.