Breeding and Management Experience for Rearing Juvenile Stone Frogs
Stone frog farming is still quite common in our country. Anyone who has eaten stone frog knows that its meat is extremely delicious, so wild stone frogs fall far short of meeting people's demand. Moreover, everyone had best not hunt wild animals at will, as this would disrupt the entire ecological balance of the environment.
Breeding and Management Experience for Rearing Juvenile Stone Frogs
After 70 days of rearing, the tadpoles complete metamorphosis, grow out their four limbs, and become juvenile stone frogs. They change from aquatic to amphibious and are transferred into juvenile frog ponds for rearing. The juvenile frog pond has a water depth of 50—60 cm, with 200—350 stone frogs stocked per square meter of water surface. Live bait such as aquatic earthworms, fly maggots, and yellow mealworms is added, and formulated feed may also be appropriately mixed in for feeding. They are fed once each morning and evening. An insect-attracting lamp can also be installed above the water surface to lure moths at night as frog bait. As the frogs grow larger and their jumping ability increases, the stocking density must be gradually reduced, and they are continually transferred into adult frog ponds for rearing.
Living Habits of the Stone Frog
The stone frog belongs to the flowing-water life type. It often inhabits small streams with relatively slow currents in mountainous areas or in still pools beside flowing streams, where the vegetation on both banks of the stream is abundant. They seldom leave the water, and their body color often adapts to their dwelling environment. Their secondary sexual characteristics have developed toward a strongly embracing mode: the male is larger in body, has extremely robust forelimbs, and very well-developed nuptial spines. These features are closely related to their reproductive characteristics. When spawning, the male and female must lay eggs at the stream bank washed by flowing water; during mating, the male embraces the female powerfully and, with the help of the spines on its abdomen, strengthens the male's grip so that they are not scattered by the current.
The stone frog has an internal vocal sac, and its call is low, muddy, and loud. The male's call is “gu gu gu,” and the female responds with a “ka ka ka” sound. The stone frog has the habits of living in groups and foraging at night. Often several or several dozen of them pile together and share one dwelling place. In quiet and suitable environments, stone frogs also come out of their burrows to forage during the day, and night is the peak period of activity. Stone frogs are good at jumping and climbing. Ordinarily, they are relatively inactive and steady; during the peak breeding period, they are frequently active and exhibit behaviors such as calling and amplexus.
Stone frogs like to eat moving animals and generally do not eat dead or motionless food. In the natural state, the stone frog has a broad diet. Besides insects, centipedes, spiders, millipedes, snails, spiral shells, clams, earthworms, and shrimp, it also preys on crabs, miscellaneous fish, loaches, young snakes, and small birds. Stone frogs in different regions also differ in diet because the environment provides different baits. In nature, the stone frog generally swallows an amount equal to 9% of its body weight, and sometimes up to 12.8%.
Breeding Techniques for the Stone Frog
The stone frog is a nationally protected animal and also a delicious dish on people's dining tables. Artificial farming of the stone frog is not only of great significance for protecting the ecological environment but also brings high economic benefits. Artificial breeding is the key to successfully farming stone frogs. Its key techniques are introduced below.
1. Selection of Breeding Frogs
The spawning and hatching season of the stone frog is from March to October, and April—June is the peak spawning period. To increase the spawning rate and hatching rate, after the breeding frogs recover from hibernation and before mating and breeding, preparations such as the selection, mating, spawning, and hatching of breeding frogs must be done well. Selecting breeding frogs is the foundation for good artificial breeding. After hibernation and before spring breeding, adult frogs should be comprehensively inspected and classified. Those with a relatively large body, robust health, smooth skin, good development, no disability, no injuries, and sexual maturity are kept for breeding: generally, a two-year-old female frog with a body weight of more than 150 grams has reached sexual maturity, and a male frog of more than 200 grams can be used for breeding. Frogs spawning for the first time produce fewer eggs; frogs that have spawned 1—2 times produce a higher quantity of eggs and better quality. Large, old frogs produce many eggs but of poor quality with a low fertilization rate, so they generally should not be selected as breeding frogs. Male frogs are required to be robust, good at jumping, with smooth skin and strong legs; female frogs are required to have short, thick legs, a bulging belly, and glossy skin. Breeding frogs aged 2—3 years have relatively strong reproductive capacity.
2. Cultivation of Breeding Frogs
Air temperature, water temperature, water quality, light, bait, and environmental conditions greatly affect the health and reproduction of frogs. Whether the living environment is suitable directly affects the mating spawning quantity, fertilization rate, egg hatching rate, and tadpole survival rate. According to the habits of the spiny-breasted frog, the breeding frog pond should be built in a quiet place with weak light. The pond is 0.8 m high and has an area of 6 square meters. The pond bottom is lined with stone cavities formed by pebbles and stones and concealed with aquatic plants, which is favorable for frogs to inhabit and spawn. The water-to-land area ratio in the pond is 2:1. The pond water capacity is required to be relatively stable, with a water depth of 8-10 cm, fresh water quality, a pH value of 6.5-8, and no harmful parasites. Generally, during the peak feeding season, the water is changed once a day; during the off-feeding season, the water is changed once every 2-3 days. Each pond holds 20-30 pairs of male and female frogs, kept in groups at a male-to-female ratio of 1:1. The selected breeding frogs must be prepared for group rearing before hibernation or before spring breeding.
Prevention and Treatment of Common Diseases of the Stone Frog
1. Trichodiniasis
[Symptoms] The body surface and gill surfaces show bluish-gray patches, or the tail turns white. This is formed by the mucus secreted by diseased tadpoles and dead epidermis. This disease is most prevalent from May to August and mostly occurs in ponds with high density and slow tadpole development. When the parasites attach to the gills, they make breathing difficult, cause floating on the water surface, and then lead to mass death.
[Prevention and Treatment Methods] 1. Before stocking, thoroughly clear and disinfect the pond with povidone-iodine, control the stocking density, and always keep the water quality fresh, which can prevent the disease. 2. For treatment, a mixture of 0.5 ppm copper sulfate and 0.2 ppm ferrous sulfate (total concentration 0.7 ppm, splashed over the whole pond) can be used.
2. Gas Bubble Disease
[Symptoms] The abdomen swells like a ball, balance is lost, and the tadpole floats on the water surface. If not rescued in time, it causes death. It mostly occurs in cement ponds with high water temperature and high nitrogen content in the pond water, causing tadpoles to lose balance in gas exchange, with excessive gas contained in the blood vessels of the intestines, gills, and skin.
[Prevention and Treatment Methods] 1. The most effective method is to change the water. First, move the diseased tadpoles into a water area with fresh water quality for temporary rearing for 1-2 days. 2. During high-temperature periods, sufficient constant flowing water must be maintained.
3. Saprolegniasis
[Symptoms] Large amounts of water mold hyphae grow and multiply on the body surface of diseased tadpoles, like old cotton-like white hair, and they often swim slowly by the pond edge. After any trauma is caused, accompanied by crowding of tadpoles, hydrolytic enzymes make the wound difficult to heal, causing the tadpoles to be restless and uneasy, lose appetite, and die from exhaustion. This disease is most prevalent in late winter and early spring.
[Prevention and Treatment Methods] 1. Thoroughly clear and disinfect the pond with povidone-iodine. 2. Handle netting and transportation operations as carefully as possible to avoid injuring the tadpoles. 3. Use erythromycin at 0.05-0.01 ppm and sprinkle it over the whole pond. 4. Use 1.4-3 ppm Chinese gallnut and splash it over the whole pond. 5. Soak in a 2 in 200,000 potassium permanganate solution for 30 minutes.
In the process of farming stone frogs, disease prevention is very important. Only when diseases are well controlled can the profits of stone frog farming be better improved. Therefore, it is very necessary to first master the living habits of the stone frog and then master the prevention and treatment methods of some common diseases.