The artificial culture technology of mandarin fish, which is one of the most valuable fish.

Mandarin fish grow fast, in general, it can reach 50 100g in that year, 0.5kg in the next year, and 1.5kg in the third year. From the age of 4 winter, the growth rate of body weight and body length slows down. In natural waters, the largest individual mandarin fish reaches more than 7kg.

Artificial propagation of mandarin fish

The sexual maturation of male fish takes 2 years, and the female fish matures at 3 winter age, but the environment is good. 1 winter-old male fish can also extrude semen. The number of eggs laid by females varies with individual size, environment and age, ranging from tens of thousands to 1.5 million eggs. When the reproductive season is from May to July and the water temperature is above 21 ℃, females prefer to lay eggs in beaches with running water less than 1m at the bottom of the upstream gravel, with a male-to-female ratio of 1:1. Mandarin fish often chase in estrus at night, with females spawning and males ejaculating. When the water temperature is 21 ℃ 24 min, the fertilized eggs can hatch a fry with a total length of 3.8 mi 4.5 mm after about 73 hours. When the body length is 5.1 mm, teeth have appeared in the upper and lower jaw, and the fry can swim horizontally in the water. The front part of the body is deep purplish red and the second half is transparent. Only a small purplish red shop can be seen in the water, with a big head and a kiss tip.

Artificial breeding and hatching:

1. Collect and cultivate parent fish. Combined with fishing on the large water surface in winter, mandarin fish with no injury, full age and good gonadal development were selected as parent fish, with a sex ratio of 1:1, mixed culture in a special pond or in a grass carp parent pond, and the mandarin fish was used to remove small wild miscellaneous fish in the original pond so that each fish was in its place to achieve sexual maturity and reserve.

2. To induce spawning: the best water temperature is from late May to mid-June when the water temperature is 25 ℃. The spawning pond conditions are the same as those of domestic fish and should be stimulated by running water. Luteal hormone-releasing drugs can be used to induce labor, about 30 micrograms per kilogram of body weight, the dose of male fish can be halved, about 16-22 hours can be oestrus and spawning, artificial insemination.

3. Hatching: domestic fish hatching loop and incubator can be used, but the water quality should be fresh and oxygen is sufficient to prevent the entry of large plankton and rotifers. When the water temperature is constant at 25 ℃, it takes only 30 hours for fertilized eggs to hatch.

Seedling cultivation: nurtured in a small pool with micro-running water. Mandarin fish are mainly fed with live fish and shrimp all their lives. When artificial labor is done, fish fry such as Tuantou mackerel or fine-scale oblique jaw mackerel must be propagated in advance or synchronously, so as to feed the mandarin fish, otherwise they will die of starvation. It can be bred to 2.6-3cm (commonly known as summer flower fry) within one month, which generally requires 200 Mel 300 bait fry.

Adult fish culture techniques:

1. Monoculture: the area of the special pond should be 0.5 Mu, and the water quality is fresh and micro-flow. Using small wild miscellaneous fish such as wheat ear fish with low economic value or overpropagated tilapia fry and shrimp as fodder, 1000 mandarin fish and summer flower fish are released per mu, which can produce about 100ml 150kg of commercial mandarin fish. The feed coefficient is 2.

2. Mixed culture: mixed culture of domestic fish with a large number of wild mixed fish in adult fish ponds, as a source of mandarin fish bait. There are 40 summer flowers per mu, which will not harm the large domestic fish. However, the water quality should not be too fat. In the prevention and treatment of domestic fish disease, mandarin fish should be carefully applied because they are sensitive to drugs such as copper sulfate.

3. Captive culture: in the breeding pond of parent fish, it can not only eliminate the wild miscellaneous fish in the pond, ensure the growth and development of parent fish, but also obtain high-quality commercial mandarin fish. 50 summer flowers can be raised per mu, with a yield of 5kg per mu, which can be listed on the market in the same year.