Key Technical Points for Overwintering and Emergence Period Management in Wood Frog Farming

1. Overwintering period management

After October each year, when the temperature drops below 15°C, wood frogs descend from the mountains one after another. During this time, aside from commercial frogs being harvested, the remaining breeding frogs and young frogs all move down to the edges of gullies and streams, preparing to select overwintering sites for hibernation.

There are mainly two overwintering methods for wood frogs in enclosed-gully frog farms: one is natural overwintering by relying on gullies, streams or reservoirs; the other is overwintering in overwintering ponds. In the former case, the frog farm's gullies and streams are relatively wide, water sources are sufficient, and there are small reservoirs with larger water surfaces; these can serve as natural overwintering sites for wood frogs. Overwintering in overwintering ponds involves building overwintering ponds at the places where wood frogs concentrate as they descend the mountains, so that they overwinter in the ponds.

The key management points during the overwintering period are:

(1) Adjust the water level to prevent water cutoff or freezing solid. Maintain a sufficiently deep water level, generally no less than 1.5 m. Prevent water cutoff in severe winter, ensure a 1 m deep water layer beneath the ice, and keep it in a flowing state. For those hibernating in river channels, also pay attention to checking the ice-flooding conditions of the river channel. If ice flooding is found, promptly find ways to clear the river channel to prevent drying up and flow cutoff, which could freeze the wood frogs to death.

(2) Prevent and reduce human disturbance, mainly to prevent breaking the ice to catch fish.

(3) Prevent attacks by natural enemies. During hibernation, the main harmful enemies are rodents, water rats and carnivorous fish. The preventive methods are setting mouse traps or rat poison, etc.

2. Emergence period management

In spring, wood frogs wake from hibernation and leave the hibernation sites to come to the breeding site. This process is called emerging from dormancy, also called emergence. In enclosed-gully frog farming, they are generally allowed to emerge naturally, that is, the wood frogs overwintering in the overwintering ponds naturally leave the ponds and come ashore. People catch and collect breeding frogs on the shore and send them to the breeding site.

The emergence period is not the same in different places, and varies because the speed of temperature rise differs. It should be handled according to local specific conditions.