Management techniques for the hatching and metamorphosis stages in forest frog farming

In mid-March, the water temperature in the Suzhou area is generally around 9—15~C, and the fertilized eggs hatch into tadpoles after about 5 days, with a hatching rate of about 85%. The main factor affecting the hatching of fertilized eggs is temperature: when the water temperature is below 6~C, both the hatching speed and the hatching rate decrease markedly. Light itself has no real effect on the hatching of fertilized eggs, but light can affect hatching by raising the water temperature. We conducted such an experiment: a cluster of fertilized eggs was divided into two halves. Half of the eggs were placed in a dark environment with a water temperature of about 11 ba, sufficient oxygen, and no light at all, while the other half were placed in an environment at the same temperature, with sufficient oxygen and with light. After 5 days of hatching, the hatching rates were 89% and 85% respectively, showing no significant difference in hatching rate.

After the tadpoles hatch, under water temperature conditions of 7—26~C they grow hind limbs in about 25 days, forelimbs in about 33 days, and complete metamorphosis in about 39 days, with a metamorphosis rate above 90%. The growth and development of tadpoles are closely related to temperature and food. At a water temperature of 10-20~C, tadpoles feed actively; above 23~C or below 8~C, their feeding activity decreases markedly. Newly hatched tadpoles mainly eat the egg jelly membrane. Before the hind limbs grow out, animal food and plant food each account for half; after the hind limbs grow out, they mainly take animal food. Tadpoles generally reduce their feeding markedly about 7 days before metamorphosis. After the tadpole's four limbs grow out, before the tail is absorbed they do not feed and mainly rely on absorbing the nutrients of the tail to survive. At this time, Chinese forest frogs mostly move near water sources and return to the water when encountering an emergency.