Matters needing attention in forest frog breeding?

China wood frog (commonly known as Hashma) is a precious amphibian. The oviduct of female China Rana chensinensis is called "frog oil", which is a precious tonic and strong product. China Rana chensinensis has tender meat and delicious taste, which is not only a delicacy at people's banquets, but also frog oil and Rana chensinensis series products are in short supply at home and abroad, and are favored by merchants.

The breeding practice in recent years has proved that the artificial breeding of Rana chensinensis in China is an efficient industry with low input and high output, which has great development prospects.

First, keep frogs in the ditch

China wood frog is an amphibian, which lives in the forest in summer and completely on land. Overwintering underwater in winter. Therefore, it is necessary to conduct scientific investigation and selection of frog breeding sites.

(1) topography and landforms

Frog farms generally choose the high mountains on both sides and the middle valley, which is what farmers call "two mountains and one ditch" as the best. If the environment is wide, it must have a width of150-200m or more. There should be a large area of concentrated flat land in the valley to build breeding grounds. The relative height of the mountain range is above 100 meters, and the gentle slope is suitable.

(2) Forest

Forest is the main growth area of Rana chensinensis in China, and Rana chensinensis in China lives in the forest for about 5 months every year. The forest types in which Rana chensinensis lives in China are mainly broad-leaved forest and mixed coniferous and broad-leaved forest.

The level of the forest should be appropriate, that is, the arbor layer should be dense, so that the crowns are close to each other, the light under the forest is dim, and the shrub layer should be lush, which is conducive to regulating the light and humidity under the forest. Herb layer and litter layer should be selected in places with lush plants and thick litter layer to provide enough food and good habitat for Rana chensinensis.

(3) Water source

The situation of water source is another important condition for choosing frog farm. There must be enough water in the dry season, that is, there are one or several small mountains and rivers on the farm that do not dry up in summer and do not flow in winter. Streams are based on sand or silt, and the amount of water cannot be too large or too small. Generally, width1-3m and depth 0.3-0.5m are appropriate.

Second, the selection and construction of breeding grounds

(1) Selection of breeding sites

The breeding ground is the breeding ground of Rana chensinensis, and the process from laying eggs to becoming young frogs should be completed in the breeding ground. The breeding ground should be located in the center of the whole frog farm. Choose a flat, large and sunny place for centralized construction. It is required that the breeding ground is close to the river, and the river can be diverted for self-flow irrigation. Cohesive soil with good water-holding performance is suitable for soil quality. Breeding grounds should be concentrated rather than scattered. In order to facilitate the evacuation of tadpoles, several breeding grounds can also be established in farms with long valleys to breed and stock them nearby. The breeding ground should be within 2000 meters of the stocking ground to avoid the death of tadpoles during long-distance transportation.

(2) Farm construction

The farm is mainly composed of four kinds of ponds: spawning pond, hatching pond, feeding pond and metamorphosis pond. The first three types of ponds should be concentrated, the deformed ponds should be reasonably distributed in frog farms, and the dry ponds should be built in areas with low temperatures.

1, spawning pond, hatching pond, feeding pond. In order to make effective use of breeding grounds and facilitate management, these three ponds can be built according to the standards of breeding grounds after testing. Each pond is a rectangle of 20-40m2, with a depth of about 0.5m, a width of about 0.4-0.5m under the ridge and a width of about 0.3-0.4m above the ridge. The whole ridge should be trapezoidal. A safety pit with a mouth of 50 cm and a depth of about 0.3 cm should be built in the pond to prevent the tadpoles from dying without water. Ponds should be built in rows, and a main canal should be built between two rows of ponds. Each pond should have oblique outlet and inlet, and outlet and inlet on the same side, so as to adopt different irrigation methods according to different production periods. Attention should be paid to prevent water leakage during construction, and joints can be filled with mud. In severe cases, plastic film can be covered on the bottom of the pool to keep water, and then sand and gravel can be laid on the surface of the pool bottom to prevent sludge from polluting the egg pieces. In some areas with low temperature, one or several sunning pools should be built in the upstream of the farm, so that the river water can be heated through the sunning pool before being injected into the breeding pool. The solar pond is also built according to the terrain, with a water depth of 0.3-0.4 meters, and the area should be large or small according to the conditions, so as to provide sufficient water for the aquaculture pond.

2. Abnormal pool

The metamorphosis pond is a place where tadpoles go ashore to metamorphose, and it also plays an evacuation role. Therefore, the metamorphosis ponds should be evenly distributed at the water edge of the frog farm to avoid the local density of young frogs when they go up the mountain. The metamorphosis pond should be built on the hillside of Chaoyang as far as possible, because the temperature is low in spring, and the sunny slope is more suitable for the growth of young frogs. The deformed pond has an area of 25-30 square meters and a depth of about 50 cm. The whole pond is pot-bottom-shaped, that is, the stalks of the pond have a certain slope, which is conducive to the young frogs coming out of the water and going up the mountain. Because tadpoles breathe a lot during metamorphosis, they need a lot of irrigation to keep oxygen content and pond water clean. Therefore, it is necessary to choose a place with water to build a metamorphosis pool.

Third, reproductive technology.

The breeding technology of Rana chensinensis in China is an important link in production, and the level of breeding technology is directly related to the benefits of artificial breeding of Rana chensinensis in China. The breeding techniques of Rana chensinensis in China mainly include seed selection, spawning, hatching and feeding.

(1) Breeding eggs and frogs

At present, the production of frog breeding is mainly based on breeding eggs, supplemented by breeding frogs, and most of them are collected in the wild, one is self-catching and the other is acquisition.

1, the collection and transportation of breeding eggs, which is time-saving, labor-saving and low-cost, is widely used by farmers at present. In still waters such as natural blisters and swamp puddles, the earlier the fishing time, the better. The egg mass produced quickly is small in size, elastic, difficult to disperse and convenient to transport. Because the oviposition peak of Rana chensinensis in China is 5-8 am, the best time to catch frog eggs is 6- 1 1 am. The means of transport for seed eggs can be a bucket. For long-distance transportation or long-term production of frog eggs, sprinkle a small amount of water in the bucket to avoid egg group adhesion.

2. Collection, transportation and selection of cultured frogs

(1) Spring Collection. Rana chensinensis in China usually leaves the river from early April to mid-April every year. From mid-April to the end of April, spawning began when the water temperature was10-1℃. Therefore, we should seize the time to collect frogs in spring and catch them in rivers, swamps or wild natural gas bubbles.

(2) Autumn episode. Every year from the middle of September to the middle of 10, it is the time for forest frogs to go down the mountain and enter the river, during which a large number of frogs can be caught. Catching frogs should use nets, hands and jars, and it is strictly forbidden to catch them by drugs or electric shocks.

(3) purchase. At present, many frog farmers adopt the method of purchasing eggs to breed frogs, which is an important way to solve the problem of provenance and can supplement the shortage of self-catching. However, it should be noted that it is necessary to grasp the time when buying breeding frogs in spring, and the females after ovulation are ready to lay eggs in the next year, because the capture rate is low, so the effect is not great.

(4) transportation of frogs. No matter what method is used to obtain breeding frogs, damage should be avoided. Farmed frogs must be packed in bags or baskets. Do not use string, wire, etc. Through the eyes, nostrils and upper and lower foreheads. During long-distance transportation, it should be packed in a cage, covered with straw, etc., and often sprinkled with water to keep humidity. The middle must be washed with clean river water to avoid the frog's body drying out and causing death. There is no need to transport frogs in water during transportation. When transporting in spring, it is necessary to grasp the transportation time, and long-distance transportation is not allowed. If it takes more than 5-6 days, the frog will expel the unfertilized eggs without "hugging".

(5) Selection of frog species. At present, there is no selection standard for breeding frogs. According to the growth cycle of Rana chensinensis and practical experience in recent years, breeding frogs should be 3-4 years old, with strong physique and weight of about 50 grams, and the body color standard, that is, dark brown, is better.

(2) Oviposition method

There is a big difference between artificial spawning ground and natural spawning ground. The density of artificial breeding frogs is high, so the forest frog is unwilling to lay eggs in the spawning ground. It must be forced to lay eggs in the spawning ground under artificial control. The methods of laying eggs can be cage spawning and ring spawning.

1, cage spawning method. Weave a cage with thin iron wire or branches, put good frogs in it according to the ratio of female power 1: 1, then put the cage in the spawning pond, and adjust the water depth appropriately to keep the water depth in the cage at about 15 cm. Spawning cages should be placed in still water, away from water outlets and water inlets. After frogs are paired, they can lay eggs in 7-8 hours at the water temperature of 10℃. Pay attention to accurately grasp the time, transfer the frog eggs to the incubator in time, and take out the hatched frogs and send them to the dormancy field. If spawning ponds, hatching ponds and feeding ponds are built according to unified standards, several ponds in the middle and upper reaches can be selected as spawning ponds.

2. Circle spawning method. Enclose the spawning pool with plastic film or barbed wire. The height of plastic film or barbed wire is 1- 1.5m, which inclines inward at an angle of 45-60 degrees, or the upper end is folded inward at right angles, and the lower end is compacted with soil. It is appropriate to place the breeding frogs in the ratio of 1: 1, and the density is 10- 15 pairs per square meter. In order to improve the mating speed, male frogs can be increased by about 10-20%, and the egg balls and breeding frogs should be transferred in time after spawning. If spawning ponds, hatcheries and feeding ponds are built according to unified standards, the whole breeding ground can be enclosed, which is convenient for management and extremely convenient and feasible.

(3) incubation method

Practice has proved that the natural incubation method is better. Natural incubation refers to the hatching of frog eggs with natural water temperature, which is basically similar to the hatching method of natural wild frogs, that is, the eggs are put into the hatchery according to the number of balls per square meter 15, and let them hatch naturally. Several problems should be paid attention to in the process of hatching: First, the egg pieces should be placed in shallow water when hatching, and then moved to deep water after the egg pieces expand. If the egg mass is directly placed in deep water, it will easily sink to the bottom of the water and be polluted due to its unexpanded buoyancy. In addition, the water temperature in deep water is low, the hatching speed is slow, and frog eggs are easy to waste. 2. In the early stage of incubation, the same side water inlet, the same side water outlet and closed (semi-closed) irrigation mode should be adopted to keep the water surface stable and the water temperature. The water depth in the pool is about 20 cm-30 cm, so it should be covered at night because of the low temperature. Third, we should pay attention to prevent egg balls from being polluted by sludge. Use Artemisia stems and branches to set small squares on the surface of the pool to control the egg pieces in a certain area to avoid floating to the edge of the pool and being polluted. Fourth, we should pay attention to prevent the invasion of natural enemies and expel poultry in time, especially domestic ducks and frogs. Fifth, attention should be paid to keeping the environment quiet during incubation, avoiding the vibration of the pond ridge and not stirring the incubation pond to store water. Six, the incubation period of water temperature should be controlled at 10- 15℃. The results of expert experiments show that the proportion of female frogs can be increased by 20-30% at this water temperature.

(4) Feeding method

The reproduction of tadpoles is directly related to the growth and development of tadpoles and the quality of deformed young frogs.

Types and processing of (1) erbium materials. Erbium material is divided into concentrate and coarse material. Concentrates are mainly corn flour, bean cake powder, wheat bran and so on. Coarse materials are mainly tender stems and leaves of various plants, such as dandelion and wormwood (except toxic ones). The processing technology of concentrate is mainly to process a small amount of fish meal into corn flour, bean cake and wheat bran according to the ratio of 3: 1: 1, mix them evenly, add water to cook them into paste, and feed them after cooling. The process of coarse material processing is mainly to process tender stems and leaves into small pieces of 2-3 cm, then cook them and cool them for later use.

(2) feeding. Put the cooked and cooled feed in the shallow water next to it for tadpoles to eat. Putting method: Stick bait on the branch of chrysanthemum morifolium, which is about one meter long, and put it into the water, so that it floats on the water surface, or both ends stand up, which is not only beneficial for tadpoles to eat evenly, but also can improve the feed utilization rate and prevent water pollution. You can also use narrow strips with a width of 2 cm, a thickness of 1 cm and a length of 1 m, and the effect is better. The feeding amount of bait should be determined according to the different growth stages of tadpoles: in the early stage of tadpoles, no bait can be fed for about a week; About 7- 10 days old, you can feed it once every morning; 10-25 days old, once in the morning and once in the afternoon; About 25-35 days, the appetite is large, and it is thrown once a day in the morning, afternoon and afternoon at the peak. At present, there is no clear standard for the amount of bait, and it can be properly fed according to the number of tadpoles. Based on the fact that there is a little surplus in each feeding, the food intake of every 10 thousand tadpoles can reach 2-3 kilograms at about 35 days old. Tadpoles entered metamorphosis at the age of 40 and have basically stopped eating. Due to the different development speed of tadpoles, careful observation should be made in the actual production process, and flexible feeding methods and bait feeding should be adopted to avoid insufficient or excessive bait.

In addition, it is an excellent feed to grind the by-product (limb) of China Rana chensinensis oil. Feeding method: feed the processed feed powder with a small amount of corn flour and vegetables according to the above method.

(3) Irrigation technology

There must be enough water in the pond at tadpole stage, and it is a key technical problem to master irrigation technology correctly.

Tadpoles have low initial temperature and low oxygen demand, so the water flows through the solar pond and the main canal, and then enters and exits the water at the same side of the pond to ensure the water temperature and the relative stability of the water in the pond. At night or on cloudy days, the irrigation amount should be increased to make the water depth reach about 50 cm, which can not only keep warm, but also prevent icing. At the late growth stage of tadpoles (after 30 days old), the temperature gradually increased and the oxygen consumption of tadpoles increased. Therefore, the oblique irrigation method should be adopted to increase the irrigation amount and water changing speed, which can not only reduce the temperature, but also keep the water clean and increase the oxygen content.

Fourth, stocking technology.

Tadpoles should be evenly dispersed in the farm after metamorphosis to prevent the local density of young frogs from being too high after landing, causing a large number of young frogs to die. Therefore, when tadpoles are 40 days old, they should be evacuated to metamorphosis ponds manually, with a density of about 5,000 metamorphosis ponds per square meter, and about 50,000 tadpoles can be put into each hectare of farms. After tadpoles are evacuated to the metamorphosis pond, attention should be paid to prevent them from being washed away by mountain torrents and the harm of natural enemies. At the same time, it is necessary to continue to feed a small amount of bait to ensure sufficient water and keep the water clean. Where the temperature is low, you can clean up the smooth branches around and increase the light. Or use plastic film to lay the bottom to raise the water temperature.

Verb (abbreviation of verb) overwintering technology

Like natural forest frogs, artificially bred forest frogs basically overwinter underwater. Because the number of artificial frogs far exceeds the number of wild forest frogs, the natural conditions of the river can not fully meet the needs of breeding forest frogs, so it is necessary to build artificial wintering places for forest frogs. First, arrange natural rivers. In the deep water area of natural rivers, it should be deepened, widened and expanded appropriately. If there are many forks in the river, it needs pruning and merging, so that the river is concentrated and the water is sufficient, and the forest frog can safely overwinter. In some deep water areas, there are few natural hidden objects, so it is necessary to add hidden objects such as grass stalks and stones. The second is the concentration of forest frogs. A small reservoir is built on one side of the river bed, with the water storage depth exceeding 1.5 meters, and hidden objects such as straws and stones are put in for the forest frog to overwinter. Artificial reservoirs can be released in a decentralized way, so that forest frogs can freely find wintering sites. You can also use the method of cage culture, put some grass stalks and other things in the cage as hidden objects, and then put the forest frog into the wintering pool.

The following problems should be paid attention to when the forest frog overwinters in the reservoir: First, it is necessary to check the change of water quantity in the overwintering river, especially in1-February of the following year. When the water quantity is low, it is necessary to regularly check the river section to avoid freeze-drying without water and freeze the forest frog to death. Second, some reservoirs belong to dead water areas, so it is necessary to open air holes frequently to ensure the oxygen demand of forest frogs. Third, pay attention to prevent natural enemies such as weasels and mice.

Six, fishing technology

Every autumn, Rana chensinensis is obese, and Rana chensinensis oil has good quality and high economic value, which is the best opportunity to catch Rana chensinensis in clusters.

At present, the capture methods of artificially cultured Rana chensinensis in China mainly adopt plastic film interception method and urn capture method. These two methods have the advantages of high fishing rate, little damage to wood frog, simple fishing and low cost. In addition, it can also be caught by methods such as turning over stones, net catching and straw trapping.

(1) The plastic film interception method refers to the method of setting a plastic film fence to intercept and catch the forest frog on the downhill line of the forest frog. At the selected forest edge, a fence with a height of 1.5m and an angle of 45-60 will be enclosed with plastic film, and the lower end will be tamped with soil. Dig a ditch with a width of 0.5- 1m in the fence, and fish in the ditch in rainy weather from mid-September to1early October.

(2) The urn method is a fish dock-shaped cage made of wicker and elm wood, which is slightly larger than the fish dock. At the end of August every year, an inverted eight-shaped urn mouth should be built in a place with large slope and fast flow speed, and a large number of wood frogs can be caught by installing the urn mouth in mid-September.

No matter what method is adopted, it is necessary to avoid damaging the forest frogs as much as possible, and carefully select a certain number of cultured frogs for separate storage. Immature young frogs should be sent to the wintering ground quickly, and mature commercial frogs should be sold as soon as possible.

Semi-closed frog breeding method for ecological comprehensive incubation in greenhouse

This method is suitable for farming in mountainous areas. Choose natural conditions rich in water, trees, vegetation and insects as frog breeding grounds. 120-160m2 plastic shed is used for artificial incubation and young frog breeding. It is stocked in mountainous areas in summer, and recycled and put into reservoirs for wintering in autumn. Because of the heat preservation, rain protection, artificial water regulation, temperature regulation, feeding and no natural enemies in the greenhouse, the survival rate of young frogs can be as high as 95%, while that of wild frogs is only about 50%. Young frogs landed nearly two months earlier than wild frogs. Due to the artificial breeding of breeding insects in the early stage, the young frogs grow fast and have strong predation and jumping ability after entering the forest to guard against natural enemies. The semi-domesticated Rana chensinensis has conditioned reflex. When the temperature is low in autumn, the recapture rate is generally as high as over 38%, up to 46%, which is 30-38% higher than that of wild China Rana chensinensis, and the production cycle is shortened from 3 years to 2 years. This method has the characteristics of low investment (3000 yuan can raise more than 654.38+10,000 frogs), large breeding amount (300,000-500,000 young frogs are raised in a greenhouse with a square meter of 1.20), high capture rate and good benefit.

Three-dimensional comprehensive ecological closed cultivation method in greenhouse

This method is suitable for breeding in courtyards, suburbs, farmland, greenhouses, orchards, barren hills and other places with water sources. Tadpoles are hatched in plastic greenhouses, young frogs are raised in a small area in summer and caught in autumn. The greenhouse breaks the hibernation of young frogs, and artificially propagated insects are put in to fatten them quickly. Its characteristics are centralized feeding management, few natural enemies, high loss recovery rate, quick effect, and one can be slaughtered. Using 500 square meters greenhouse to raise grapes, vegetables, forest frogs, insects and other comprehensive ecological three-dimensional culture, 50 thousand frogs can be raised, with an annual income of more than 6.5438+10 thousand.

Indoor high-density rapid intensive cultivation method

This method is suitable for family buildings, bungalows and large-scale factory farming in most areas. First, mating, spawning and hatching of breeding frogs are carried out in indoor shed or outdoor plastic shed, and young frogs ashore are raised. Then, according to the bionics principle, artificial breeding insect feed is put into the indoor three-dimensional cage box, and 500 young frogs, 300 young frogs and commercial frogs 150 can be cultivated per square meter by adopting the methods of constant temperature rapid fattening and high-density intensive breeding. Young frogs can be released after 4-6 months, and can be raised all year round, and three batches of young frogs can be raised every year. Three-dimensional culture 100 square meter, only needs 1 person management, and the net profit can be 1.5-22000 yuan in 4-6 months. This method is not limited by conditions and climate, and has the advantages of unlimited investment and scale, easy management and quick effect, with a survival rate as high as 85% and a harvest rate as high as 100%. It has a good promotion value and is highly valued by relevant leaders and experts and strongly supported by scientific research institutions.