Detailed Explanation of Key Points for High-Efficiency Breeding of the Black-Spotted Frog
The black-spotted frog (Pelophylax nigromaculatus) is an amphibian of the genus Pelophylax in the family Ranidae. In recent years, over-hunting has caused the wild population of black-spotted frogs to decline sharply, and the excessive use of pesticides has left their population status highly concerning. At the same time, a species of Manson's tapeworm (Spirometra mansoni) parasitizes the bodies of wild frogs and can easily harm human health. Therefore, artificial breeding of the black-spotted frog is imperative. Let us take a look together at the high-efficiency breeding technology for the black-spotted frog below!
Growth Habits
Black-spotted frogs are fond of living in groups, often with several or dozens living together. During the breeding season, they gather in groups in the still water of rice paddies and ponds to amplex and lay eggs. During the day they often hide among weeds and aquatic plants in marshes, ponds, rice paddies and other water areas, and come out after dusk and at night to move about and hunt. They generally begin hibernation in November, burrowing into sunny slopes or crack-resistant sandy soil not far from water, at a depth of about 10-17 cm. In the cold regions of Northeast China, black-spotted frogs can burrow 120-170 cm or more into sandy soil, and emerge from hibernation in mid-March of the following year.
Feeding Habits
1. Tadpole stage: During the tadpole stage, the black-spotted frog is omnivorous and can feed on both plant and animal food. After hatching, the tadpole mainly relies on absorbing nutrients from the yolk sac to sustain life, and begins feeding on single-celled algae, plankton and other food in the water after 3-4 days.
2. After metamorphosis: After the black-spotted frog tadpole metamorphoses into a young frog, its food consists mostly of arthropods of the class Insecta, such as Coleoptera, Diptera, Orthoptera, Hemiptera, Homoptera, Lepidoptera and so on, and it also swallows small amounts of snails, shrimp, and small fish of the Cyprinidae and Cobitidae families.
Fry and Seed Stocking
1. Selection of breeding frogs: For breeding black-spotted frogs, choose those that are physically strong, free of injuries and disabilities, and disease-free. Usually the female frog is somewhat larger in body size than the male, and when the male calls, the external vocal sacs on both sides of its throat swell up.
2. Stocking of breeding frogs: Black-spotted frog breeding stock is stocked in September-October at a density of 10-12 frogs per sq m, with a male-to-female ratio of 1:1. The breeding frogs hibernate in the breeding frog pond and then begin to amplex and lay eggs around Qingming Festival of the following year.
3. Amplexus and egg-laying: Black-spotted frog breeding stock begins to amplex freely when the average temperature reaches 16-20°C, and lays eggs after 3-4 days of amplexus. Egg-laying generally occurs at 5-6 a.m. and from 11 a.m. to 1 p.m.
4. Collection of egg masses: After the fertilized eggs of the black-spotted frog are collected, they are placed into the disinfected ring ditch of the breeding pond to hatch. The darker side of the egg mass is the animal pole and must face upward, while the whitish side is the vegetal pole and must face downward.
Tadpole Rearing
1. After hatching, tadpoles are reared in the original hatching pond or in net cages, at a stocking density of 600-800 per sq m of water surface. For the first 4-5 days they generally do not eat anything, mainly obtaining nutrition from their own yolk sac. After the yolk sac disappears on the 4th day, artificial feeding begins.
2. From the 5th day after hatching, tadpoles are switched to soybean milk, wheat bran, tofu residue combined with livestock feed, or rice bran and fish meal and other livestock feed, fed 1-2 times a day. Livestock feed is placed on feeding trays, and powdered feed is first mixed with water into a thick paste before being splashed on for feeding.
3. From 20-30 days after hatching, tadpoles gradually take bloodworms, water fleas and maggots as their main food, and can also take soybean milk, soybean residue, soybean cake powder and chlorella as their main food. Adding a certain amount of fish meal can promote their growth.
4. During tadpole rearing, if bubbles appear in the pond water or the water quality has a rotten odor, replace it with fresh water immediately. Generally change the water once every 3 days, and once every 2 days during prolonged drought and continuous high temperatures.
5. About 70 days after hatching, tadpoles become young frogs. From the appearance of the forelimbs to complete metamorphosis, this stage relies on absorbing energy from the tail. When more than 90% of the tadpoles have become young frogs, they can be transferred to the young frog pond for rearing.