Overwintering management of forest frog cultured in closed ditch

Rana has the habit of hibernating underwater. From the last ten days of September to the middle and last ten days of April of the next year, the overwintering management of artificial ditch cultivation of frogs is to artificially select and create suitable overwintering places and water environment according to the living characteristics of Rana chensinensis in this period to ensure its safe overwintering.

1. Construction of winter ponds

Wintering pool is also called hibernation pool, is a place where Rana concentrated hibernation. Some natural blisters, deep water inlets or reservoirs in frog farms can be used as natural overwintering ponds for frogs, but most frog farms need to build overwintering ponds artificially.

1. The site is selected at or near the place where Rana chensinensis descends in autumn, beside the river channel (stream), avoiding the river channel for 5-10 meters, and selecting the flat terrain and sticky soil as the place for building the wintering pool.

2. The specifications and quantity of the wintering pool are required to build a wintering pool with a depth of 3 - 4 meters, a water depth of 2 - 2.5 meters, a flat bottom, a slope of 70 - 80 degrees around, and a landslide after water immersion. If the bottom of the pool is sandy and loose, it should be padded with clay to prevent water seepage. The construction area and quantity of wintering pond depend on the terrain condition of frog farm and the quantity of perennial wintering frog. Flat open terrain, can build large wintering pool, single pool area of 800 - 1000 square meters, poor terrain conditions can build small and medium-sized wintering pool. The area of a single pond is 200 - 300 square meters; the number of overwintering ponds is determined according to the number of overwintering frogs cultivated throughout the year, and the overwintering density of adult frogs is generally 80 - 100/square meter, and the young frogs are 200 - 300/square meter. A frog farm builds 3 - 4 small and medium-sized wintering ponds, which can accommodate 20,000 - 300,000 frogs and 150,000 - 300,000 young frogs. When building multiple wintering ponds, the interval between them should reach 500 - 1000 meters, so as to achieve single irrigation and single row.

II. Preparation before using wintering pond

Wintering ponds recycled for many years. The sludge at the bottom of the pool is thick, affecting the water storage capacity, and accumulating a large number of Rana chensinensis pathogens and natural enemies, so it should be carefully trimmed before the winter period.

1. Desilting releases the pool water, removes the silt from the bottom of the pool, and restores it to the bottom of the original pool.

2. After removing the silt, it is necessary to control the inflow of water and expose the bottom of the pool to the sun for 20-30 days to kill some germs and pests.

3. 20 - 30 days before water injection, quicklime is sprinkled on the bottom and surrounding walls of the pool for disinfection. This method can effectively kill pathogens, leeches, parasites and other natural enemies of Rana chensinensis.

4. Lay a layer of broad-leaved tree leaves about 5 cm thick or grass bundles at the bottom of the pool before watering, and then cover them with gravel and sand. These shelters are conducive to the hibernation of Rana chensinensis underwater.

5. Water injection at the end of October, Rana chensinensis into the winter before hibernation pool full of water, water depth to 2.5 meters, keep clean.

III. Overwintering management

In the middle of September, when the temperature drops below 10 ℃, Rana chensinensis begins to migrate to the water source at the foot of the mountain. At first, it enters the shallow water area to lurk. From the beginning of November to the middle of November, the temperature drops below 5℃, and the frog enters the deep water area to hibernate until the end of March to the beginning of April of the next year.

1. The hibernation period is managed from mid-September to early November, 45 - 50 days. The characteristics of this period are that most of the frogs are scattered and latent in shallow water areas, in an unstable hibernation state, and can still move to land at night. The key points of management in this period are: separating the captured frogs according to commercial frogs, breeding frogs and annual young frogs, and sending the breeding frogs and young frogs to frog storage ponds respectively for storage. Frog storage pool depth of 40 - 80 cm, frog storage density of 500 - 800 per square meter of water surface. Frog ponds can be used both as hatchery ponds and tadpole breeding ponds. If there is sufficient river water in the frog farm, it can also be temporarily replaced by a wintering pool, that is, keep the depth of the wintering pool 50 - 80 cm. The overwintering frog is put in, and the overwintering pool water is replenished to 2 - 2.5 meters deep in time before the frog enters hibernation in early November. Surrounding the frog storage pond, plastic sheets should be used to form a fence with a height of 50 - 60 cm, and the bottom should be compacted by labor to prevent the frog from escaping. Because Rana chensinensis lurks in shallow water, man-made theft and predation of various carnivores should be prevented during management and protection.

2. Centralized hibernation period management from early November to the end of March of the following year, this period is characterized by Rana concentrated in deep water areas, crowded together, do not eat motionless, in a deep hibernation state. The key points of management during this period were:

1. Transfer overwintering frogs in frog storage pond to overwintering pond in time. The density of frogs released in the overwintering pond is 80 - 100 frogs/square meter and 200 - 300 frogs/square meter, and the living water is maintained for overwintering. Winter in Northeast China is cold, and many rivers and streams in farms will freeze and stop after entering winter. The density of Rana chensinensis in winter ponds should be reduced by half.

② During the winter, observe the water flow frequently and keep the water level under the ice not lower than 1.5 meters.

③ After snow falls, it is necessary to clean up the snow on the ice surface or sweep out the snow path in time to enhance the transparency of the pool water.

4. Put rat traps and rat poison around the wintering pond at fixed points to prevent the harm of carnivorous natural enemies such as rodents.