Techniques of High-yield Culture of Freshwater White Pomfret in Pond

Freshwater white Pomfret, scientific name short cover giant fat carp, is a kind of excellent tropical large economic fish, which has many advantages, such as fast growth, large individual, miscellaneous diet, strong disease resistance, high catching rate, delicious meat, rich nutrition and so on. This variety was first introduced in Hexian County in 1998. From 2001 to 2004, our station successfully carried out a demonstration of high-yield culture in freshwater Pomfret pond in Tongyi Farm of Liyang Town for 4 consecutive years, and the yield per mu was maintained at about 1000 kg, with considerable economic benefits.

First, pond conditions. The farm is located in the north of the city, close to a branch of the Shiba River system, far away from factories and residents' living areas, with adequate water sources, good water quality, separate drainage systems and no pollution sources around. The aquaculture pond mouth is rectangular, east-west, with an area of 0.57 hectares, a water depth of 1.5-2 meters, a flat bottom, a slope ratio of 2.5-3, and is equipped with a 3-kilowatt impeller aerator.

Second, prepare the pond. Every winter, the pond should be dry and exposed to the sun, and the pond should be cleaned with quicklime around April 15, 2002. Dry cleaning of the pond, the amount of quicklime per mu is 75 kg; wet cleaning of the pond, the amount of quicklime per mu is 150 kg. 10-15 days before stocking, adjust the water depth of the pond to 1.2-1.3 meters, and install the aerator.

3. Stocking of seedlings

1. Stocking time. As a tropical fish, freshwater Pomfret has poor tolerance to low temperature. Fish can be released only when the water temperature is kept above 20-22 ℃. The general stocking time is mid-May, no later than the end of May. It is best to choose a sunny noon when stocking.

2. Seedling source. The free-range fish species come from Tianbang Fisheries Research Institute, Xiangquan Town, Hexian County. The fish species cultivated by the institute using hot spring resources are robust and well-proportioned.

3. Stocking quantity and specification. Due to the many advantages of freshwater Pomfret culture and superior pond conditions, we put them in accordance with the standard of 1200 fish per mu. In order to facilitate the early listing, the stocking specification is 12-15 tails / kg. Before stocking, soak in 3-5% sodium chloride solution for 5-8 minutes and temporarily keep it in the pond for 2-3 hours. In addition, in order to improve the water quality of the pond, 100 silver carp and bighead carp fingerling with specifications of 6-10 fish / kg per mu were put in according to the proportion of 6:1 per mu.

IV. Feed feeding

1. Fixed point. That is, the fixed feed feeding place is not only convenient for the freshwater white Pomfret to eat, but also convenient for the staff to check the eating condition of the fish.

2. Quality determination. That is, do not feed spoiled and moldy feed. The types of feed are: wheat, soybeans, rice bran, animal carcasses, slaughterhouse leftovers and special formula feed. For plant feed, once mildew occurs, it should be stopped immediately. For rotten animal feed, the feeding times and amount should be reduced. Otherwise, the quality of adult fish will be affected. In our production, we mainly choose wheat, black soybeans and special formula feed to ensure that the crude protein content in the feed is ≥ 25%.

3. Timing. They were fed four times a day at 9 o'clock, 11:00, 14:00 and 16:00 respectively. The pellet feed for freshwater white Pomfret was fed at 9: 00 and 14:00, and the mixture of wheat and black soybean was fed at 11:00 and 16:00.

4. Quantification. When feeding, the feeding amount should be determined according to the growth rate, growing season and weather of freshwater Pomfret. The weight of the fish should be measured every 10-15 days, and the feeding rate and amount should be determined according to the weather and temperature. Generally speaking, during the growth period of freshwater white Pomfret, the feeding rate is 3-4% in the initial stage, 4-6% in the middle stage, and 7-8% in the later stage.

V. Daily management

1. Water quality management. In order to ensure the freshness of the water quality of the culture ponds, the water is usually changed 15-20 cm every 15 days. During the high temperature period from July to August, more than 10 cm of water should be added at least every 5-10 days.

2. Patrol the pond. Its purpose is to observe the eating and activity of the fish and the color and quality of the pond. It is necessary to persist in doing a good job in patrolling the pond every morning and carefully observe the activities of the fish. Patrol the pond more closely when it is hot at noon and when it is muggy and rainy. As soon as there is any abnormal situation, take corresponding measures in time.

3. Disease control. As a kind of fish with strong disease resistance, freshwater Pomfret is not easy to be infected with disease. In the process of breeding, we should focus on the following prevention work.

Prevention of ⑴ bacterial diseases: timely sprinkle quicklime, the dosage is 15-20 mg / kg, not only improve water quality, but also prevent the occurrence of bacterial diseases.

⑵ floating head floodpond: every morning and noon on a sunny day in summer, the aerator should be turned on at the right time to increase the amount of dissolved oxygen in the water to prevent the occurrence of floating head flooding pond phenomenon.

VI. the key to the high yield technology of freshwater Pomfret.

First, when stocking, the specifications of fish species should not be too small, the specifications should be consistent, and the disparity should not be too large, and we should not deliberately raise fish species of various specifications in the same pond in order to consider the future rotation and listing. Second, freshwater white Pomfret is omnivorous bottom fish, the main culture, the pond can not release other bottom fish, otherwise it will affect the yield per mu. Third, the stocking time of freshwater Pomfret is generally in the middle of May, and the water temperature is stable above 20-22 ℃. If the stocking is too early and the temperature is unstable, it is easy to affect the survival rate; too late, it will affect its growth rate, which is not conducive to early listing. Fourth, the freshwater white Pomfret has a large amount of food and greedy mouth, must be fed according to the four methods, a small number of times, not too much. In production, we have found the phenomenon of eating to death of freshwater white Pomfret.