2. Culture method of mandarin fish
First, the preparation of mandarin fish pond
Ponds with better conditions should be selected. Siniperca chuatsi pond should be miniaturized, generally 2 ~5 mu is better, east-west, close to the water source. Especially the newly dug pond is the best. The water depth of the pond is 1.5m ~ 2m, so it is convenient to enter and leave the water. Install filters and gates at the water inlet and outlet to facilitate catching mandarin fish and prevent fish from escaping.
Before Siniperca chuatsi enters the pond, the pond should be cleaned up, too much silt should be dug up, and the bottom of the pond should be fully basked in the sun. About 20 ~30 days before sowing, put 10 cm ~20 cm of water, and use 20 ppm bleaching powder (30% available chlorine) per mu. Sprinkle quicklime 100 kg ~ 150 kg to disinfect the pond. After disinfection, irrigate 80 cm ~ 100 cm to cultivate water quality. During irrigation, wild fish and enemy creatures should be prevented from entering the pond. After disinfection for 7 days to 10 days, the medicinal properties disappeared. Try to release some fish and put them in the fish basket for 24 hours. If there are no abnormal dead fish, they can be released. If there are dead fish, it will take a few days to release them. Mandarin fish fry are under the dam. What are you doing? Cong? Do what? BR> stocking mode of mandarin fish: from June to July, 2,000 to 3,000 mandarin fish summer flowers are stocked per mu, and 300 to 500 kilograms of mandarin fish can be harvested in winter; For example, if the summer flowers are released per mu 1000 ~ 1500, the commercial fish with specifications of 250g ~ 500g/ fish can be harvested in winter150kg ~ 200kg; Spring slices of Siniperca chuatsi were released in March and April, with 700 ~150g per mu and 50 ~ 1000 pieces. Before the Spring Festival, 200kg ~ 250kg of commercial fish with specifications of 50g ~ 750g can be harvested.
Second, the source and feeding technology of bait fish
Siniperca chuatsi fry take other live fry as opening bait, preferably young fish, such as tilapia fry, bream bream fry, crucian carp fry, etc. The fry of four big fish can also be used. With the improvement of feeding ability of Siniperca chuatsi larvae, they can prey on all kinds of juvenile fish, and then transition to fingerling and adult fish. The main sources of bait fish are:
1. Buy four big fish splashes and cultivate them into bait fish in a short time. Mid-May is the breeding season for the four major fishes. The four major fish are splashed in large quantities and cheap, so they can be purchased in large quantities and temporarily kept in closed cages. Generally, it needs 1 1,000,000 ~11,500,000 per mu. With the continuous growth of Siniperca chuatsi fry, domestic fry also grow synchronously, which is always a palatable bait for Siniperca chuatsi.
2. Cultivate and collect wild miscellaneous fish fry. Carp, crucian carp, Megalobrama amblycephala and some wild miscellaneous fish can reproduce when they are sexually mature in April. You can choose 1 ~3 mu fish pond, and put 40 ~50 kg of crucian carp parent fish in each mu, with the male-female ratio of 3: 1. Hang 3 ~5 rows of brown chips in the fishing pond, flush before dawn to urge crucian carp to estrus and lay eggs, collect brown chip fish nests and cultivate them in another pond. Four weeks later, millions of crucian carp fry can be obtained, and by June, the crucian carp grows to 1 cm ~2 cm, which is an ideal bait fish for mandarin fish. To breed 1 mu mandarin fish, 4-5 mu bait fish ponds are needed.
Third, the activity law of Siniperca chuatsi and the mastery of bait
Siniperca chuatsi moves in shallow water or coastal zone at the initial stage of stocking, and moves in open water or middle-low water after adapting to the environment, so it is difficult to observe its activities during the day and night. In order to observe the growth and physique of Siniperca chuatsi, estimate the number of bait fish and judge the survival rate of Siniperca chuatsi, according to several years' production experience, a more effective method is summarized, that is, setting an open cage in the pond, putting bait fish in the cage, luring Siniperca chuatsi to move in the cage by throwing bait, regularly capturing some samples of Siniperca chuatsi from the cage for determination and analysis, and then guiding fishery production according to the determination and analysis results.
Keeping enough palatable bait fish in the pond is an important measure to promote the rapid growth of Siniperca chuatsi and reduce the bait coefficient. After Siniperca chuatsi enters the pond, it is necessary to carefully observe the feeding situation of Siniperca chuatsi and estimate the density of bait fish, so it is necessary to observe diligently and master flexibly. Usually, bait fish larger than the mouth crack of Siniperca chuatsi and smaller than the mouth crack will not be preyed. The size of bait fish is about 40%~60% of the body length of Siniperca chuatsi, and the body width should be smaller than the caliber of Siniperca chuatsi. It is best to feed mandarin fish for 4 ~5 days at a time, neither more nor less, sometimes not. In a word, enough bait fish density should be maintained in the pond to make Siniperca chuatsi easier to prey. The feeding rate of Siniperca chuatsi is different at different growth stages and different water temperatures. When the bait fish is sufficient, a large number of fresh mandarin fish feces can be observed floating on the surface of the pond. At sunrise or sunset, bait fish gather near the pond and are often chased by mandarin fish. The feed coefficient of mandarin fish is usually between 4.2 and 6.8. Before feeding the bait fish, 60ppm~ 100ppm formalin, 8ppm copper sulfate, 20ppm potassium permanganate and other drugs should be soaked and disinfected from different sources, and the appropriate soaking time is 10 minute ~ 15 minute.
4. Water quality management of mandarin fish pond
Keep the water fresh and the dissolved oxygen sufficient. Siniperca chuatsi likes fresh water quality, requires high dissolved oxygen and has poor hypoxia tolerance. Therefore, according to the change of water quality and weather, fresh and pollution-free water should be slowly added every 7 days to 10 days, and the amount of water injected each time is 10%~20% of the pool water. It would be better if the pool water could be kept in a state of micro-flowing water. Generally, the pond water should be changed gradually after applying copper sulfate for 3 ~5 days to avoid the influence of drug residues and dead algae on the water quality. And according to the weather changes, you can flexibly master the start time and times of the aerator. When the weather is sultry, when it is found that Siniperca chuatsi spits out bait fish, it is necessary to start the aerator in time, inject fresh water to make the water body full of dissolved oxygen, and at the same time, put 100 ~200 silver carp per mu to control algae reproduction and avoid excessive water quality. You can also raise a small amount of water hyacinth to purify the water quality.
Five, strengthen the prevention and control of fish diseases
Siniperca chuatsi is easy to be infected with parasites at seedling stage, and the more harmful ones are rotifers, oblique tube worms, fish lice, anchovy snapper and so on. 0.4ppm~0.5ppm trichlorfon and 0.08ppm~0. 1ppm powerful pesticides can be used to control fish lice and anchovies. The mixture of 0.7ppm copper sulfate and ferrous sulfate (5: 2) was selected for rotifer and trypanosoma; The mixture of 0.4ppm~0.45ppm copper sulfate and potassium permanganate (5:2) has good control effect. Generally, after the occurrence of pests and the killing of parasites, the whole pool should be sprayed with bactericidal drugs for disinfection. The most common disease of adult mandarin fish is gill rot, which can be controlled by 1ppm bleaching powder and 0.3ppm~0.5ppm chlorine dioxide. In case of fulminant hemorrhagic disease, 0.5ppm chlorine dioxide and 0.5ppm efficient disinfectant are selected for prevention and treatment, and the effect is good. In addition, every 15 days, 20 kg ~25 kg of quicklime is sprinkled in the whole pool per mu per meter of water depth to adjust the water quality and prevent diseases.