Chinese Rana sylvatica artificial breeding technology
China's Rana sylvatica is an economical frog species of specialties in the Northeast. In recent years, resources of wild Rana sylvatica have drastically decreased, and supply exceeds supply. Various forms of Chinese Rana sylvatica artificial breeding have been carried out in various places, and as long as there are water sources of creeks, gorges and marshes. The area can be farmed in places where there are woods and plants in and around it. There are two feasible methods for artificial breeding of Chinese Rana sylvatica: First, control the culture method, and control the frog in a well-established breeding farm for high-density artificial breeding. This method has a large investment, high scientific and technological management, and high risk. , It is not appropriate to promote breeding; the second is artificial hatching, natural stocking, which is also a lively and vigorously promoted breeding method in many localities. This method is simple, low investment, easy to manage, and the benefits are considerable. The author introduced the latter breeding technology to a large number of farmers, aiming to make the artificial breeding of Rana chensinensis grow in a healthy and orderly manner.
First, the basic conditions for breeding Chinese Rana's site selection The breeding site must have the basic requirements for the biological characteristics of Chinese Rana sylvatica, that is, there must be clean streams, dense forests, adequate food, and partitioned mountains.
1. Water sources must have rivers or mountain streams that are free of pollution, cleanliness, adequate water supply, and small water bays with water depths of 1m to 2m to facilitate the colonization and hibernation of Chinese forest frogs.
2. The forest has a large area of ​​broad-leaved forests around the frog farm, undergrowth shrubs, and appropriate weeds, forest canopy closure, litter layer thick, moist, in order to facilitate the land frogs of Chinese forest frogs life.
3. Mountain ridges Chinese frogs are adapted to the life of mountain forests in the evolutionary history. Therefore, in order to prevent the escape of farmed Chinese forest frogs, mountain ridges formed by the connection of Jiayigou and Gaoshan in the two mountains are selected as breeding grounds, and the slope direction is to the southeast or southwest direction. As well.
4. The growth rate of food Rana chensinensis depends on the adequacy and variety of food. Therefore, there must be a large number of insects in and around the frog farm to ensure the growth and predation of Chinese Rana sylvatica. The frog's food includes spiders, aphids, snails, stink bugs, flies, mosquitoes, cockroaches, moths, chafers, ants, cockroaches, aphids, ladybugs, etc.; frogs and adult frogs are basically the same, except that they catch small animals under 12mm. Insects only.
Second, the construction of Chinese forest frog farms
1. Spawning hatchery for spawning and hatching of female frogs, with an area of ​​10 m2 to 20 m2. Pool length 5m or 10m, width 2m, water depth 0.3m, where there is leakage of water can be laid plastic film, and build a 0.6m wide, 0.5m high soil around the pool. Both the inlet and the outlet are built on one side of the pool, so that a large area of ​​hydrostatic zone can be formed in the pool and the water temperature can be increased. The inlet and outlet are sealed with plastic nets to prevent escape. After hatching, it can be used as a rearing pond.
2. The hibernating pool is used for the breeding of frogs and frogs for hibernation. The pool water depth in winter is kept above 2m. There must be some roots, stones, and tiles in the bottom of the pool as hidden objects.
Third, the hatching and feeding
1. Collection of egg masses From Ching Ming to Gu Yu is the best time to collect Chinese Rana's egg frogs. Do not break the gray protective film when collecting the egg mass, and collect the same growing egg pieces and store them separately. The egg mass of Chinese Rana temporaria eggs is all black, and the egg plate resembles a net-like circular sink. Each egg mass has about 800 to 1500 granules. It is worth noting that: The frog's eggs are semi-white and semi-black, and the spawning time is 1 month to 2 months later than that of the Chinese Rana sylvatica. The eggs of the frog are long strips.
2. Egg hatching The collected and synchronized egg masses were placed in hatchery tanks at 5 reunions per square meter to 6 remnants per square meter. The water temperature is the main condition for hatching. When the water temperature is low, the incubation time is long, and the earthworms are stunted and the survival rate is low. Therefore, the water temperature should be increased and the water temperature should be kept constant. The most suitable water temperature is 18°C ​​to 25°C. When the water temperature is constant at 18°C, larvae can be hatched in 4 days; when the water temperature is constant at 25°C, larvae can be hatched in 2.5 days (56 hours). In order to increase the water temperature, a plastic film can be used to cover the hatchery. Freshly hatched quail lying on the bottom of the hatchery or adsorbed on the wall of the surrounding pool, within 6 days of nutrition with its own yolk, do not have to feed.
3. Feeding The artificial feeding started from the 7th day after hatching from the earthworm, and the daily feeding amount of 10 days to 20 days old earthworms was 83 mg/only to 124 mg/head, and the day cast of 20 days old to 25 days old earthworms. The feeding amount was 125 mg/--166 mg/only, and the daily feeding amount of the 25-day-35-day-old pupa was 167 mg/-200 mg/only. Starting from the 20th day of age, quail eating animal feed can chop fresh fish, meat, etc., and put it on the edge of the hatching pond for eating. At the same time, chop the eucalyptus leaves, narcissus, madder, etc. Cooked, stacked and fermented at any time in the hatchery for food.
4. Daily management Firstly, to maintain and increase the water temperature in the hatchery, cover the plastic film above the hatchery at night or on rainy days. Second, pay attention to increase the dissolved oxygen content in the pool water. The water injection and drainage should be slow to keep the hatchery pool. There is a large area of ​​still water; the third is to prevent predators, such as water mice, water snakes, other frogs, larvae, leeches and other predators.
5. Disease prevention and control At the age of 20 days, the density of earthworms should not exceed 1,000 per square meter. Immediately transfer the dense earthworms to other rearing ponds for rearing. If the larva culture density is too high, it is prone to trichodiasis. The disease manifests as pale white part of the cercariae, severe systemic whitishness, slow growth, and finally death; the prevention and control method is to use a copper sulfate 0.7g/cubic metre to dilute the whole pool. And pay attention to keeping the water fresh. During the flood season, it is also susceptible to tongue and cup worm disease. The treatment method is the same as that of trichodiasis.
Fourth, feeding and management of young frogs After 50 days to 60 days of feeding, the forelimbs begin to grow and enter the metamorphosis period, at this time should stop feeding artificial feed.
After becoming a baby frog, it is also the highest mortality rate of Chinese forest frogs, so we must strengthen management. After a complete metamorphosis, the young frog must go ashore within 3 days and must start feeding, otherwise it will die in large numbers. To help young frogs go ashore, one end of the frog can be put into the rearing tank with a plank, a stick, etc., and the other end is placed on the pool floor as a springboard for the young frog to land, and a pile of bean curd residue is placed every 2m on the pool ridge. Or feces or semi-fermented weeds, to attract small insects and small insects for breeding, for larvae after landing. Plants of dense origin can also be planted in advance to attract insects for predation by young frogs.
In order to increase the survival rate of young frogs and accelerate the growth of young frogs, artificial evacuation of the metamorphosis larvae must be performed. The method is to dig a metamorphosis pit every 50n to 100m near a forest edge, a stream, and a large number of insects. The area is 2 square meters to 5 square meters, and the depth is 30cm. Water can be stored temporarily. In the metamorphosis pit, abnormal limbs forming protrusions or protruding forelimbs are raised at 120 animals per square meter and become frogs after 3 to 4 days, allowing them to begin their terrestrial life near the mountains.
V. Wintering Management In early October each year (before and after frost fall), Chinese Rana sylvatica enters hibernation. In order to make it safe for wintering, clean riverbeds, streams or hibernation pools, and put large rocks in rivers or in winter sights. Dig out some artificial burrows with large mouths and small mouths at the whirlpools or on the banks of riverbed turn. To be in the water. It is also possible to block the ends of some hollow trunks (diameters greater than 20cm) and put them into places where the water flow is slow and where the water level is deep, so as to prepare for the hibernation of Chinese Rana sylvatica. After being frozen, the Chinese Rana sylvatica began to concentrate in places with deeper water levels and turned into long-term, deep-seated hibernations. At this time, it was necessary to strengthen management to prevent theft.
The young frogs can be harvested for 4 years, and the best season to catch Rana sylvatica is from late September to early October of each year. At this time, frog oil is hypertrophic, the quality is good, the oil production is high, and the price is high.
Author: Dandong City Fisheries Technology Extension Station, Liaoning Province
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