Efficient Culture techniques of Rana nigromaculata

Rana nigromaculata is an amphibian of the genus Rana in the frog family. In recent years, the number of wild Rana nigromaculata has plummeted due to excessive predation, and its population status is very worrying due to the excessive application of pesticides. At the same time, a kind of Taenia mansoni parasitic in wild frogs is also very easy to endanger human health, so artificial breeding of black spotted frogs is imperative. Let's take a look at the efficient breeding techniques of black spotted frogs.

Growth habit

Black spot frogs like to live in groups, often a few or dozens of them live together. During the breeding season, groups gather in the still water of rice fields and ponds to hold each other and lay eggs. During the day, they often hide in weeds and weeds in swamps, ponds, rice fields and other waters, and come out at dusk and at night to hunt for food. Usually hibernating begins in November, drilling into sunny slopes or crack-resistant sandy soil not far from the water, about 10 to 17 centimeters deep. In the cold areas of northeast China, the black spot frog can drill below 120 to 170 centimeters in the sand and sting in mid-March of the following year.

Feeding habit

1. Tadpole stage: Rana nigromaculata tadpole stage is omnivorous, and both plant and animal foods can be eaten. Tadpoles live mainly by absorbing yolk sac nutrients after hatching, and begin to eat unicellular algae and plankton in water 3-4 days later.

2. After metamorphosis: after metamorphosis, the tadpoles of Rana nigromaculata have the most food of arthropod insects, such as Coleoptera, Diptera, Orthoptera, Hemiptera, Homoptera, Lepidoptera, etc., and swallow a small amount of snails, shrimp, Cyprinidae, Loach and so on.

Seedling stocking

1. Breeding frog selection: black spotted frogs should choose strong, disability-free and disease-free frogs for breeding. Usually, the female frog is larger than the male frog, and the external vocal sac on both sides of the neck of the male frog expands when he cries.

2. Breeding frogs: black spotted frogs were released from September to October with a density of 10: 12 per square meter, with a male-to-female ratio of 1:1. Breeding frogs began to hold pairs before and after Ching Ming Festival began to lay eggs before and after hibernation in frog ponds.

3. Cuddle pairs to spawn: black spotted frogs begin to cuddle freely when the average temperature reaches 16-20 ℃, and lay eggs after 3-4 days, usually at 5: 6 a.m. and 11:00-1 p.m.

4. Egg block harvesting: the fertilized eggs of Rana nigromaculata are collected and put into the sterilized aquaculture pond to hatch. The darker side of the egg mass is the animal pole, which must be upward, and the white side is the plant pole, which must be downward.

Tadpole rearing

The main results are as follows: 1. After hatching, tadpoles are cultivated in the original hatching pond or cage. 600 million 800 tadpoles are reared per square meter of water surface. They generally do not eat in the first 4-5 days, mainly with their own yolk sac for nutrition. After the yolk sac disappears on the 4th day, artificial feeding begins.

2. From the 5th day after hatching, tadpoles were fed with soybean milk, wheat bran, bean curd residue, rice bran, fish meal and other livestock feed, once or twice a day, the livestock feed was put on the feed table, and the powdered bait was first adjusted into a sticky shape with water and then splashed.

3. After 20-30 days of hatching, tadpoles gradually feed on red worms, water fleas and fly maggots, as well as soybean milk, soybean dregs, soybean cake powder and Chlorella. Feeding a certain amount of fish meal can promote their growth.

4. When breeding tadpoles, if you find bubbles in the pool water or the water quality has a rotten smell, you should immediately change the new water, generally every 3 days, dry weather for many days, continuous high temperature, change the water every 2 days.

5. Tadpoles become young frogs about 70 days after hatching. The period from the appearance of forelimbs to complete metamorphosis depends on the absorption of tail energy. When more than 90% of tadpoles become young frogs, they can be reared in juvenile frog ponds.