The key techniques of raising Pelteobagrus fulvidraco

In order to cultivate Pelteobagrus fulvidraco, the key work is to do a good job in the prevention and control of diseases and insect pests.

First, make preparations in winter. Both new and old ponds must be cleaned and sterilized before releasing seedlings. The old pond should remove too much silt and retain a silt layer of 10 cm thick. Every winter, the fish species go through the pool or adult fish out of the pond, drain the pond water, clean up the sludge at the bottom of the pond and trim the pond foundation, so that the pond is exposed and cracked. (1) clear the pond. ① dry pond first drain the pond water (or leave water 6cm deep), every 667m2 (1mu) with quicklime 75100kg, depending on the amount of sludge at the bottom of the pond. When cleaning the pond, first emulsify the quicklime with water, and sprinkle it evenly all over the pond without cooling. After clearing the pond, the medicine usually disappears after 7 days and 10 days, and the fish can be released. ② cleaning pond with water: when the water depth is about 1 meter, 125kg to 150kg of quicklime is used every 667m2. The disinfection method is the same as the dry pool disinfection method, and its disinfection effect is better than the dry pond method. (2) bleaching powder to clear the pond. General bleach contains about 30% available chlorine, and its dosage is 15 kg per 667 square meters. First dissolve the bleach with water and sprinkle it all over the pond. Generally, after 4-5 days, the power of the bleach disappears completely, and the fish can be released.

Second, the release of seedlings. Each large size fish of about 30 grams should be put into adult breeding, 1500 fish should be put in every 667m2, and can be matched with silver carp with specifications of 50g each. The fish species should be selected with neat specifications, bright color, smooth body surface, no defective spines and strong physique. The seedlings should be soaked in salt water with a concentration of 5% for 10 minutes before entering the pool. The species of Pelteobagrus fulvidraco are usually released in late April every year, and the matching silver carp is released half a month after the fish has been in the pond.

Third, healthy feeding. (1) preparation of bait. The food of Pelteobagrus fulvidraco in natural waters is mainly shrimp, fish and fish eggs and some aquatic insects, aquatic plants and so on. It can also be domesticated and fed with self-made compound bait, which is made of fish meal, meat and bone meal, blood meal, soybean meal, rapeseed meal, dried fish worm and other feed additives, with a protein content of more than 34% and a fat content of 4%. In the later stage, small mixed fish meal can be used to replace part of the fish meal, with a protein content of 30% and a fat content of 6%. The feed must be fresh, mildew-free and rancidity-free. (2) domestication. Two days after the seedlings entered the pond, the seedlings were domesticated by artificial feeding, and the fixed feeding signal was used to carry out fixed-point and regular feeding training. The food can be eaten normally after 5 to 7 days. The domesticated seedlings so released can be fed normally on the second day after entering the pond, and the feeding method can be in the form of manual and mechanical feeding. (3) feeding amount. The whole feeding process should be divided into three stages. The first stage is May and June, four times a day, with a daily feeding rate of 3% to 5%. The second stage is in July, August and September, three times a day, with a feeding rate of 2% and 3%. The third stage is after October, the bait is twice a day, and the feeding rate is 2%. In the first and third stages, the satiety method is recommended, that is, 90% of the fish on the bait table stop eating after leaving the table. In the second stage, due to the hot weather and fluctuating water quality, it is recommended that 90% of the fish on the bait table should be stopped after leaving the platform.

In addition, due to the large mouth crack of Pelteobagrus fulvidraco, the feed size should be increased accordingly, the particle size of 2 mm should be used as open feed, and the particle size of adult fish should be more than 5 mm. The use of sinking hard pellet feed requires that the particles have stability in water for 15 minutes, and the use of floating bait will improve the feed utilization rate.

The yellow croaker grows to 3 cm before each tail, mainly eating aquatic organisms. If there is a shortage of aquatic organisms, pure dried silkworm pupa powder can be used instead. After the body length is 3 cm, eat artificial formula feed. Two or more feeding stations suspended in the water can be set at the corner of the stocking pond, and the number of feeding stations can be determined according to the size of the fish pond and the number of fish released. The feeding table can be made of simple materials that can sink into water, and the table can be paved with soft materials such as woven bags. When feeding, knead the powdered bait or pellet with water into a small ball of 100g to 150g, throw it on the stage and let the fish eat automatically. Feed it once a day in the morning and once in the evening, and it is appropriate to eat all the basic food each time.

Fourth, water quality management. In the culture of adult yellow croaker, water quality management is the most important. In order to prevent the aging of the water body, 30 cm of new water is injected every month in May and June, 15 cm is changed every half month from June to September, and the water depth is kept at 1.2 to 1.5 meters. From June to September, the quicklime water with a concentration of 15 mg / kg was sprinkled in the whole pool once a month. Use 5kg quicklime (or 2kg bleach) locally once a month in the food farm and aerator. Persist in observing the algal phase and algal concentration of the water body, adjust the water fertility with inorganic fertilizers (urea, calcium superphosphate, potassium dihydrogen phosphate, etc.) according to the water color, and keep the transparency at 30cm to 35cm. According to the determination of dissolved oxygen and the weather and water quality, the aerator should be used scientifically, the machine should be turned on in the early morning and afternoon in sunny days, and mechanical oxygenation should be made full use of in rainy and muggy weather to supplement the lack of dissolved oxygen in water. Dissolved oxygen in water should be kept above 3 mg / L.

Fifth, disease prevention and control. In the prevention and treatment of diseases, high-efficiency and low-toxic drugs should be used as far as possible, and the varieties of drugs should be determined by observing the curative effect. (1) insecticide. Sprinkling the whole pool with 0.03 mg / kg dioxin solution has a better effect on ring worms, rotifers and so on. (2) Antibacterial and anti-inflammatory agents. The oral medicine (pressed into particles and mixed well in the feed) was mixed with 10 grams of dysentery and 20 grams of oxytetracycline, added to 50 kilograms of bait, fed continuously for 3 days, twice a day, or 5 grams of oral penicillin capsule for 3 days, twice a day. The fish were disinfected by concentrated immersion of 0.25% bleach powder or penicillin powder dilution for 10 minutes. The above oral ingredients, it is best to feed now, with a feeding for 3 days, do not put for a long time. Mainly for diseased fish infected by bacteria. (3) treatment of hemorrhagic disease. Use 50 kg of raw salt for every 667 square meters, spread throughout the pond. In order to cure the disease of yellow croaker, trichlorfon should be refused to kill insects, otherwise it will bring adverse consequences.

Try to avoid damage to fish during delivery and transportation, so as to prevent water mildew infection in the early Chung, autumn and winter low temperature seasons. If hemorrhagic edema occurs in the high temperature season, nitrogen dioxide should be sprinkled in the whole pool for 2 times, which can be treated effectively.