What are the requirements, venues and equipment for raising forest frogs?

The China Rana chensinensis is artificially bred, also called captive breeding, with the aim of semi-artificial breeding. It implements a set of artificial propagation technical measures in the whole growth process of China Rana chensinensis through artificial methods to achieve the purpose of artificial propagation. After years of experimental research and the summary of frog farmers' experience, it is proved that the technology of artificial breeding of frogs is successful, and there are still some technical problems to be solved and improved. The artificially raised forest frogs mature for two years, accounting for more than 85% of the total number of commercial frogs, and the recapture rate is more than 46% according to the stocking quantity, and the female frogs account for more than 80% of the total, which is 30-40% higher than the wild frogs. There is no difference in the quality between the artificially bred China Rana chensinensis and the wild China Rana chensinensis. Therefore, the industry of artificial breeding frogs has developed rapidly, and it has developed in three northeastern provinces and other places.

What are the main technical links of artificial breeding frogs?

First of all, solve the feed problem of wood frog. At present, Tenebrio molitor is the main feed, and natural insects and young animals are the auxiliary feed; Choose the flat land or farmland, vegetable fields and courtyards on both sides of the mountain stream as frog breeding grounds; Set up fences to solve the danger of escape and natural enemies; Set shade, cultivate vegetation and sufficient water to simulate the ecological environment under the forest; Popularize frog rapid breeding and female mutation technology to improve breeding efficiency; Popularize a variety of effective wintering methods to solve the problem of a large number of frogs dying in manual storage; To study and solve the diseases of forest frogs and their prevention and control methods, and improve the survival rate of raising frogs. The following details are introduced:

(1) Site selection and construction

The field area of artificial breeding Rana chensinensis is small, but there are many building facilities and high breeding density, which requires intensive management, especially to meet the special needs of Rana chensinensis in amphibious environment. Frog farms in mountainous areas must choose a humid and close-to-nature environment, which is stricter than half-human farming. The same place should have pools, grasslands, shrubs, forests and other multi-level shady environments. According to different site types, different stocking methods are decided. Generally, it is necessary to raise frogs in the open air in the flat land in the mountains, and streams pass through the site or pass through one side. It is required to be close to the big forest, with sparse forest shrubs and grasslands, fertile soil, thick humus layer and good ground coverage. Some places should have a meadow or hot spring water, surrounded by mountains on three sides, with the lee facing the sun and convenient transportation, and there are no tall buildings and expressway nearby. It would be more ideal if the original pool, the old floor of the pond dam and other facilities were in the field.

Another location is near the residential areas of towns and villages. You can choose fertile farmland, vegetable fields or wide courtyards, or you can use abandoned factory land or vegetable protection land. In this kind of field, frogs should be raised in the form of shading or closed net shed, and it is forbidden to raise frogs in the field without shading. The construction principle of frog farm is to simulate the ecological environment under the forest and meet the requirements of temperature, humidity, sunshine and food for the life of forest frogs. The example proves that the more the simulated frog farm resembles the natural environment under the forest, the greater the possibility of successfully raising frogs and the greater the effect. Frog farm has two basic constructions, namely, farm and frog farm.

1. Construction of Rana chensinensis farm in China

Artificial frog farms are different from semi-artificial frog farms. Usually, the oviposition, hatching and tadpole reproduction of Rana chensinensis are combined into one, that is, one pond is used for three purposes, which occupies a small area and has a high stocking density. The required pools are of high standard, connected in rows and easy to manage. One is an earthen pond. The soil of the site is impermeable, with a width of 3m, a length of 6m or 4m, a length of 10m, a pool depth of 20-30cm and a ridge height of 30cm. The inner slope of the ridge should be gentle, so as to facilitate the young frog to crawl when landing and reduce drowning when falling into the water. The bottom of the pond is flat and there is a pot bottom pit in the center. The number of ponds is determined according to the number of breeding tadpoles, arranged in the order of 1-2 rows, and trails are left between ponds.

The other is to lay the bottom with plastic film, with 5 cm of soil or sand on it, and compact the periphery outside the ridge. In order to facilitate irrigation and drainage, the pool should be built above the ground. After the bottom of the pool is leveled, the edge of the pool should be nailed with boards or bricked, and the edge should be 30cm high. The bottom and the same side should be covered with plastic film to prevent leakage, and the bottom should be covered with sediment. The size and shape of the swimming pool depend on the site and the stocking amount.

In order to hatch early and prolong the growth time of Rana chensinensis, a pond with a width of 3 meters, a length of 5-6 meters and a depth of 220-30 cm was built in a plastic greenhouse. Several ponds are connected together and the bottom is covered with plastic film. Tadpoles need a lot of water during the breeding season, so the water source of the site must be guaranteed. It's best to use well water and use constant water series irrigation to make the pool water flow. The metamorphosis pool of tadpoles is built in the frog pen.

2. Construction of frog farms

Frog farm includes fence, frog pen and wintering pool (cellar).

(1) fence

It is to enclose the breeding ground of the forest frog with the farm. Permanent fences should be made of durable materials, such as brick walls, cement slabs, rare earth slabs and asbestos tiles. The wall foundation of the fence should be leveled first, and the depth of the wall foundation should be greater than 30 cm. The joint of the fence board should be tightly sealed, with a height of 60-80 cm. The top of the fence shall be provided with an angle edge folded inward by 90 degrees, with a length of 65,438+00 cm. A set of electric cats is put outside the wall to prevent mice. The electric cat wire is 5-8 cm away from the wall and the ground. In places with serious black pollution, bird nets should be set up in places where birds often appear. If the investment is large, the fence is made of iron mesh, which has the best effect. Grass and trees should be planted around the fence, and broadleaf trees should be planted. The temporary fence is made of plastic film, gauze and woven cloth and fixed with wooden posts. The materials are changed once a year, and the general height is 0.8-1.0m. The fence construction method is the same as that of semi-artificial fence.

(2) The construction of frog circle

Frog pen is a special pen for breeding young frogs and adult frogs. Frog pens are divided into permanent pens and temporary pens, depending on the investment ability and the scale of raising frogs. Permanent circle is divided into open air and fully enclosed net shed. The fence of the open permanent open-air frog pen is made of brick, stone and other materials. The wall is 70 cm high, and the top of the wall goes out inward, perpendicular to the vertical wall. The top edge is 65,438+00 cm long, and the ring size is generally 5× 65,438+00 m, which is arranged in two rows in sequence, with a vertical wall in the middle to form a frog community, with 65,438+0 left in the interval. The structure of the simple temporary frog fence is the same as that of the permanent fence, but the materials used are different, mainly using plastic sheets and wooden columns. Each frog breeding area is equipped with a set of electric cats to defend against natural enemies. Irrigation equipment of frog pen includes channels or pipes, water spraying equipment or micro-spraying equipment. Tadpole metamorphosis pond is built in the enclosure, accounting for about 20% of the enclosure area, and part of it is also used as tadpole breeding pond and water storage tank in the enclosure in summer to control the humidity in the enclosure. The ground in the fence is controlled by drains, or made into a big ridge with a width of two feet. Put some leaves, corn stalks and other sundries in the ridge, and weeds or straws grow on the ridge. Shading belt is set at the top of the open-air circle, 2 meters high from the ground. Use 70-80% black shading net with a width of 2m and a spacing of 2-3m. There are tall trees in or near the frog circle, and there may be less or no green belts.

The investment in building a closed net shed for raising frogs is higher and the cost of raising frogs is higher. If it is necessary to transform the vegetable greenhouse into a frog ring, replace the original plastic film with a black sunshade net. This kind of sunshade net is available in the market, with a service life of 2-3 years per square meter 1. When choosing frog pens in farmland, vegetable fields and courtyards, it is best to build net sheds and implement closed frog breeding. The advantages are saving space, shading in the shed, adjusting temperature and humidity to simulate the environmental conditions under the forest, reducing the escape of forest frogs and the harm of natural enemies, which is conducive to high-density intensive management. But raising frogs is a big one-time investment. Generally, it takes 600-700 yuan to build a net shed with 100 cubic meter of material, and 50,000 young frogs can be raised.

Construction method of net shed: net shed width10m, center column height1.8m, side column height1.3m, and length 30-50m. The supporting materials are wooden poles or bamboo poles, and the ceiling is arched or ridge-shaped. The height around the ground is about 1 m, and the upper and top shed surfaces are made of nylon gauze. The ceiling and its surroundings are fixed on the skeleton with nylon silk thread, with a zipper window of 1.5m in length at one end and several zipper windows of 0.5m in length at the north and south sides, which are used as ventilation window in the daytime and tadpole metamorphosis pond controlled on the ground in the shed at night, with an area of 65,438+0.5 of the area in the shed. The depth of the pool depends on the soil conditions, and it is located in impermeable land or low-lying areas with high groundwater level. Repair the abnormal pool in the place where the soil is loose and leaking, and lay the pool with plastic film. The water depth is 20-30 cm, and the bank of the pond should be solid and the slope should be gentle, so as to facilitate the young frogs to land. The abnormal pool of tadpoles is still storing water in the shed as a pool. The ground in the shed should be dug into a cross-shaped or well-shaped ditch with a depth of 20-30 cm. Some sundries, such as leaves of broad-leaved trees, should be placed in the ditch as the habitat of young frogs during drought, and accumulated water can be drained when it rains, thus playing the role of drought prevention, waterlogging prevention and moisture retention. There are two sidewalks paved with red bricks or cement blocks in the shed, and the other ground is covered with grass vegetation. It is too late to build vegetation in the new net shed in early spring, so it is necessary to put in corn stalks and other sundries. There should be water spraying equipment in the shed, and it is best to install micro-spraying facilities. You can also install large-scale sprinkler irrigation devices on the farmland outside the net shed to carry out large-scale artificial rainfall and adjust the temperature and humidity of the whole farm.

(3) Construction of wintering pool (pit)

The artificial frog farm is located near the stream and can be used as a semi-artificial frog wintering pool for construction and management. This is the best wintering method at present. Frog farms are far away from places with running water, and forest frog wintering ponds or frog storage pits are built on the spot, some in the open air and some in solar greenhouses; There are two kinds of frog storage pits: dry storage and water storage. As long as the hibernating habit of Rana chensinensis can be satisfied, the wintering survival rate will be high, otherwise it will fail. The construction of wintering pool (pit) is introduced below.

① Construction of wintering pond by water storage method.

The construction method of the open-air overwintering pond for Rana chensinensis is the same as that of semi-artificial frog rearing, so I won't go into details here. The artificial breeding of frogs and the construction of overwintering ponds in greenhouses are relatively easy to manage, and it is easy to see the actual overwintering situation of forest frogs. If problems are found and solved in time, the survival rate is high, but frogs consume a lot of substances and their bodies are thin, and farmed frogs sleep and die a lot. In a 50-meter-long greenhouse, the suitable wintering pool is 4 m× 30 m× 0.8 m, which can store10.5 million frogs. The wintering pond can also be built semi-underground, with excavation depth of 40cm and dam ridge height of 40cm. Waterproof coiled material or plastic film shall be laid on the bottom of the pond and the inner side of the dam ridge, and the bottom of the pond shall be flat and clear of hard sundries. Both ends are provided with a water inlet and a water outlet, and the water inlet is self-flowing water or well water. The water outlet is 60cm high from the bottom of the pool, and the water depth is kept at 50cm-60cm. Drain pipes can directly drain water out of the shed or drain water. The top of the pool is supported on the dam ridge with wooden poles and covered with grass or tarpaulin. Vegetation and shelter should be reserved on the land around the pool in the shed as a place for the forest frog to land.

The method of overwintering in greenhouse or shed shallow pool is to build a simple plastic shed in the courtyard, which is twice as large as the overwintering pool. Repair the pool first, then build the shed. The pool is 4m wide, and contracts inward when it is dug to the depth of1m.. The middle 2m is dug to the depth of 1m, which is the effective width of the pool, and there is a two-story platform with a side length of1m.. The platform on the second floor and the top of the pool mouth are erected with wooden poles, covered with grass curtains or tarpaulins, and double-layer electric cat iron wires are placed outside the greenhouse and the pool to prevent rats.

(2) Dry storage method, cellar storage for overwintering.

At present, there are many examples of failure in using dry storage pits to protect Rana chensinensis from overwintering. The main reason is that the pit is not deep enough, the heat preservation effect is not good, and it is freezing to death. Some pits dry to death due to insufficient humidity; Some were destroyed by rats, and some were drowned by water because they came out of the cellar late. However, some of them are successful. Successful people's specific operations are: frog storage pit is 2-2.5 meters deep, 2 meters wide and 4-6 meters long. The pit is covered with 30 centimeters of soil, with ventilation pipes at both ends, made of iron furnace pipes, porcelain pipes and plastic pipes. The perimeter and the pit door should be fortified with rat nets, and the periphery of the pit should be equipped with electric cats to prevent rats. In case of cold, the other side should be covered with plastic shed outside the pit. Set up 4-5 layers of shelving in the cellar and put the frog storage box on the shelf. Frog storage box is made of plastic or wooden board, with holes at the bottom, which plays the role of ventilation and water leakage. The storage box is 50×60×30 cm, with 5 cm leaves at the bottom, and each box stores 500-600 frogs. The roof of the cellar is equipped with sprinkler pipes. The periphery of the frog storage pit can be made of masonry, but the bottom of the pit still maintains sediment. Some directly put forest frogs at the bottom of the pit, the density can be higher, and 4,000 young frogs or 1000 breeding frogs can be stored per square meter.

There are many wintering methods for China Rana chensinensis, but the deep-water bay and the wintering pond with running water are the best, which can meet the requirements of China Rana chensinensis for water temperature and dissolved oxygen content in water. No matter which method is adopted, this principle must be followed, otherwise the wintering rate will be low. When adopting heat preservation measures to overwinter, the temperature must be controlled at 0-5℃. It will freeze to death if it is low. If it is high, the forest frog will consume nutrients in its body, and its breathing will be blocked, leading to the frog's death.

(2) Several technical problems in the breeding period of Rana chensinensis in China.

The breeding period of Rana chensinensis in China refers to several stages: spawning, hatching and tadpole feeding and management. The specific technical measures are similar to those of semi-artificial farming. Now, several different issues are introduced as follows:

1, transportation of breeding frogs, frog eggs and tadpoles.

In order to improve the survival rate of introduction and domestication of Rana chensinensis in China, it is necessary to transport Rana chensinensis or its eggs to the frog farm in a short time, and the long-distance transportation should be completed within 2-3 days. Packing can be done in wooden cases, plastic boxes or cartons, but there should be air holes at the bottom and around. Each box has two layers and rotten leaves at the bottom. The size of the box is 70×60×60 cm, and each box can hold 6540 pieces. The short-distance transportation of breeding frogs is packed in woven bags or cloth bags, each bag contains about 200 frogs. Frogs are divided into male and female, washed with cold water, put flat on the car, put into the water immediately after being transported to the frog farm, and put into the same pool according to the ratio of male and female. The transportation and packaging of frog eggs are mainly buckets or plastic bags. Put the frog eggs produced in the same period together. It is best to transport the eggs laid that day. Don't drain water when packing eggs. If it cannot be transported to the site that day, put it in a cool place, add appropriate amount of cold water, and put it into the water immediately after being transported to the site. The transportation distance of tadpoles should not be too far, generally less than 2 hours, mainly in barrels. The barrels are filled with 1/2 cold water, and each barrel contains about 3000 tadpoles. The transportation and packaging of abnormal young frogs should be in barrels, and no water can be put in the barrels. Some leaves or weeds should be sprayed with cold water, and each bucket should contain about 2000 young frogs. After being transported to the site, they should be immediately put into a hidden place, let them move freely and lurk, and spray water to moisturize.

1, save the "submerged egg mass"

There is sediment at the bottom of the plastic spawning pond, which is easy to mix with water when planting frogs or laying eggs. Some eggs sink to the bottom of the water and are covered with sediment. The hatching rate of such eggs is only about 40%. So be sure to fish out the submerged eggs, rinse them with clear water, and then put them in a clear water pool.

2. Adjust the density and food intake

During the spawning incubation period, 4-5 pairs of frogs or egg balls are put in every square meter of water surface, and tadpoles should be emptied before eating, and feeding should be started at the age of 8 days, with 4000-5000 frogs per square meter every day, and the feeding amount is 250g; At the age of 65438+20 days, 2,500-3,000 animals are raised per square meter of water surface, and the feeding amount is 600- 1 1,000 grams per day; At the age of 25-30 days, feed 1, 500-2,000 animals per square meter of water surface twice a day, and the feeding amount is 1, 000 grams.

Step 3 control humidity

Compared with natural breeding, breeding tadpoles in greenhouse can shorten 15 days, but the temperature in greenhouse should be controlled below 25℃ to prevent high temperature burns, so the film in greenhouse should be ventilated in time or completely removed, and black sunshade curtain should be replaced if possible.

4. Improve the cleanliness of tadpoles

The frog eggs laid on the same day are hatched in the pool, so that the hatched tadpoles are basically the same, which is convenient for unified feeding and management. Frog eggs collected from the field have different spawning time, and tadpoles that hatch first will eat the glue film of the unhatched frog eggs, leading to the death of the eggs. Therefore, it is necessary to fish out the unhatched egg balls in time and put them in another pond to continue hatching, which can improve the hatching rate and reduce the phenomenon of mutual eating.

(3) Feeding and management of young frogs

Young frog refers to a young frog after metamorphosis. Abnormal tadpoles should be disinfected with 1ppm bleaching powder before entering the circle. The deformed young frog does not eat for 7-8 days and moves around the deformed pond. Attention should be paid to heat preservation and moisture preservation, and some corn stalks and other sundries should be placed beside the pond, which will help young frogs land and reduce the phenomenon of frogs dying in the water. In order to have a reasonable stocking density, we must first calculate the number of deformed tadpoles, about 2000 per kilogram of deformed tadpoles, and calculate the stocking density of frog circles according to the measurement of 80% adult frogs. Generally, it is advisable to raise 300-400 frogs per square meter, and the stocking density of net shed culture is relatively high, with 400-450 frogs per square meter. A 300-square-meter net shed can raise about 654.38+ ten thousand frogs. The water source of frog pen should be guaranteed, and the abnormal pond should be constantly replenished with fresh water to prevent water pollution; Spray water 1-2 times a day, 3-4 times in dry and hot weather, and don't spray too much water each time. It is best to soak the ground and vegetation to prevent water accumulation on the ground. In summer, if the temperature in the net shed is too high, you can spray water on the roof outside the shed to cool down and moisturize. It is important for young frogs to eat with their mouths open, but it is serious to solve the problem of dead frogs. On average, each young frog in the open-air frog pen is fed with 2-3-year-old Tenebrio molitor 1-2 every day 1 time, at 4-5 in the morning or 5-6 in the afternoon. No feeding is allowed in rainy days, and there is no water accumulation on the ground after rain. Feeding can be done in dry days after spraying water. Feeding should be evenly spread to the whole circle along the working path, and placed in the place where young frogs are concentrated. It should be domesticated into regular, quantitative and fixed feeding step by step to improve the utilization rate of bait. With the increase of frog age, the feeding amount will increase. After 40 years old, frogs are fed twice a day, and each young frog is fed with 2-3 4-5 year old Tenebrio molitor. The annual feed cost of each young frog is about 0. 10 yuan. In order to reduce the production cost and increase the food source of young frogs, black lights are set in frog breeding circles to attract and nourish insects, and wormwood and human and animal feces are piled up to attract and nourish insects. The artificial feeding amount of frogs raised in net shed is more than that raised in open circle, which is generally about twice. You can also set lights in the shed to attract insects, raise larvae such as flies and maggots, and increase the food sources of young frogs. There are many natural enemies in the open-air frog pen, so it is necessary to regularly check the integrity of defense facilities, especially the damaged fences, net sheds and caves, and repair them immediately after discovery to prevent young frogs from escaping and being hurt by natural enemies.