Management Key Points for the Tadpole Stage and Metamorphosis Stage in Forest Frog Breeding

1. Feeding and management during the tadpole stage

The tadpole stage is an extremely important period in the individual life history of the forest frog, generally lasting 40-50 days. Artificial greenhouses are a good facility for raising tadpoles.

(1) Feeding during the tadpole stage: Tadpoles are omnivorous, and their main food sources include water algae, weeds, wild vegetables, vegetables, various animal meats and internal organs, etc. Under artificial rearing conditions, in order to cultivate a high-quality group of young frogs, a certain amount of artificial feed should be provided. The specific method is as follows:

1-7 days of age: They mainly eat the egg jelly membrane and do not need artificial feed.

8-14 days of age: They eat plant-based feed, mainly soybean milk and cooked tender leaves such as sheep's sorrel leaves and creeping tick trefoil. Feed once daily at 250 g/sq m.

15-29 days of age: They eat tender linden and elm leaves, sheep's sorrel leaves, wormwood, etc., combined with concentrate feed (corn meal: soybean cake meal: fish meal: bone and meat meal at 1:1:0.5:0.5) or fish feed of equivalent nutritional value. Feed 1-2 times daily, with concentrate feed at 500-1000 g/sq m.

30 days of age: Feeding stops during the metamorphosis stage, and artificial feed is discontinued.

Tadpole feed is mainly plant-based, with the ratio of concentrate to roughage at about 1:2. The feed can be placed directly at the water's edge of the rearing pond or on feeding boards in the water.

(2) Management during the tadpole stage:

① Density adjustment. For artificially reared tadpoles, at around 10 days of age, stock 4000-5000 tadpoles per sq m of water surface; at 15-20 days of age, control the density at 2500-3000 tadpoles per sq m of water surface; at 25-30 days of age, stock 1500-2000 tadpoles per sq m of water surface.

② Principle of consistent age among tadpoles in the same pond. When artificially rearing tadpoles, high density easily causes mutual cannibalism among tadpoles, generally with the large eating the small. After tadpoles begin feeding, they pose a great threat to later egg clusters; they can quickly bite through the unhatched egg membranes, causing massive egg death. Therefore, egg clusters of the same period must be placed in the same hatching pond to ensure consistency in the age of tadpoles in the same pond.

③ Feeding. Tadpoles should be fed at fixed times and fixed locations, and the feed must maintain quality and quantity. If the amount of feed is insufficient, tadpoles will kill each other, generally with the large biting the small, or several tadpoles ganging up on 1 tadpole until it is eaten. If the amount of feed is excessive, it will seriously pollute the water quality, causing a decrease in dissolved oxygen in the pond water and easily causing massive tadpole death.

④ Pond water management. Pond water management is the key point of tadpole stage management, and its main contents can be summarized as “water quality, water quantity and water temperature.”

During the tadpole stage, an adequate water source must be ensured, with drainage and irrigation at any time. The pond water surface should be stable, and water should be added gently. In the early growth stage of tadpoles, water temperature is regulated by irrigation, carried out at 14-15 o'clock every afternoon. Generally, shallow irrigation should be used during the day and on sunny days, and deep irrigation at night or on cloudy and rainy days. In the late growth stage of tadpoles, when the water temperature reaches above 24 degrees C, the amount of irrigation should be increased to lower the water temperature.

In addition, the water level in the pond should be checked frequently, and sediments should be cleaned up in a timely manner to ensure that the rearing pond does not run out of water or become foul, and to strictly prevent pollution from sewage and pesticides. The pH value of the pond water should be 6.5-7.0. The pond water should be completely replaced once a week.

2. Management during the metamorphosis stage

When tadpoles grow to 25-29 days of age, that is, when the total length of the tadpole is 4.3-5 cm, the body length is 1.2-1.5 cm, the body is flat and round with a diameter of 0.9-1 cm, the tail length is 3.2-3.5 cm, the hind legs are basically fully developed at 1-1.5 cm, and two small protrusions appear at the forelegs, they begin to transition to the metamorphosis stage. The characteristics of tadpoles entering the metamorphosis stage are the appearance of protrusions at the forelimbs on the sides of the body, abdominal contraction and thinning, smaller body size, and cessation of feeding.

When tadpoles develop to the metamorphosis stage, if a reservoir (area 2-4 sq m) is set up within the young frog rearing enclosure, the tadpoles in the metamorphosis stage can be directly scooped out and transferred to the reservoir in the rearing enclosure, allowing them to naturally complete metamorphosis and directly enter the enclosure for rearing.

If there is no reservoir in the rearing enclosure, then after the young frogs have completed metamorphosis, they must be captured in a timely manner and sent to the rearing enclosure for rearing. When capturing, it is best to use a hand net rather than directly using hands, so as to avoid injuring the young frogs.

Before the arrival of the tadpole metamorphosis stage, plastic sheeting should be pre-selected to enclose the metamorphosis pond, and the enclosure should be required to be tight with no gaps to prevent young frogs from escaping.

During the tadpole metamorphosis stage, it is necessary to prevent predation by certain birds.