Technique of culturing green grouper in low pond

First, the transformation of the low pool selects a low pool with an area of 2000~3335m2, a pool depth of 1.8m, and a water depth of more than 1.2m, retain the original soil slope protection around the low pool, transform the bottom of the pool into sand bottom or sand bottom, and the two ends of the pool are equipped with a water wheel type aerator for each 1000m2 farming area. After the infrastructure transformation is completed, clear and disinfect the pond with quicklime according to the dosage of 100kg/667m2, and check whether the relevant facilities are in good condition.

2. seedling selection and stocking at present, the sources of blue grouper fry are natural fry and artificial breeding. considering the strong seasonality of natural fry capture, the purchase channel is not wide, and the quantity is unstable, the selected fry is artificial breeding. The main results are as follows: 1. the selection of fish fry is a fish with both cannibalism and territoriality. the purchased grouper has the best size, intact, bright color, no trauma, no deformity, good feeding condition, and the pectoral and dorsal fins are fully open. Healthy and energetic. When selecting fish fry with smaller size, you can first mark the fish fry and then put them in the pond. 2. The disinfection of fish fry should be carried out before stocking, and the disinfection of fish fry should not be carried out until 3 hours or 4 hours after the fry arrives at the breeding ground. There are many commonly used disinfection methods, we use potassium permanganate 10 × 20 × 10-6 soaking 5~10min or formalin 20 × 10-6 soaking 40~10min. 3. The stocking of fish fry put the sterilized fish fry into the standard thick pond and observe normal temporarily, then put the fish fry directly into the pond according to the predetermined stocking plan. The stocking density should not be too dense, because pond culture is not as convenient as cage culture, and it is appropriate to use 30-50 tails / m2. The temperature after the Spring Festival in Hainan is basically around 20 ℃, which is the best time for stocking. Feed and feed 1, feed fresh miscellaneous fish and shrimp feed with small miscellaneous fish and shrimp as the main bait, freshness and quality should be guaranteed. In the process of feeding, the feeding rate should be properly adjusted with the growth of fish fry, the change of body weight and water temperature, and the feeding amount should ensure that 80% of the fish are full. Generally, 40min should be eaten properly after feeding. 2. Mixed feeding of fresh miscellaneous fish, shrimp and compound feed with the continuous development of marine fish culture, using fresh miscellaneous fish and shrimp as bait, it is difficult to meet the development requirements in terms of resources. Through the experiment, some formula feed of Japanese eel or European abalone was selected and fed properly with small miscellaneous fish and shrimp, and the culture effect was not abnormal. 3. Feeding time it is observed that there is a great correlation between the growth and feeding frequency of grouper. The practice shows that the grouper fed once every 36 hours has the advantages of fast growth rate, high survival rate and high yield, which can greatly reduce the feed coefficient. The feeding time we arrange is before sunset at 7: 00 a.m. or 5: 00 p.m. Fourth, daily management to maintain a stable and good water quality environment is a management must always pay attention to. Change the water once every 20 days, the amount of water is 20~30cm, when the external water holding is good, you can change more. In the process of changing water, it is necessary to discharge sewage thoroughly, remove bait residue and fish feces, sprinkle disinfection in the whole pool with disinfectant after changing water, and disinfect again every 20 hours in 1 to 2 days. It is necessary to maintain the proper fatness and transparency of the pond water and strictly prevent the growth of moss in the pond water. the death of a large number of fish culture in the pond has a lot to do with hypoxia. Therefore, the aquaculture pond should maintain a deeper water level, and the aerator can be properly turned on according to the fish carrying capacity of the pond. generally, the aerator should be opened for 2 hours in the middle of the night in rainy days and 1 hours at noon in sunny days. Grouper is a kind of ferocious fish, it is its nature to eat each other, and the difference of individual size should be strictly controlled in the process of culture. Often patrol the pool and find that when the individual disparity is too large, it is necessary to screen and raise in separate ponds so as not to cause unnecessary losses. The incidence of grouper culture is not too high, but still need to do a good job in disease prevention, regular alternative feeding bait, regular sampling inspection, found abnormal, can be treated according to the symptoms. Fifth, grouper that is harvested and raised to more than 400g in batches can be sold. At the beginning, large fish can be caught and small fish can be harvested and sold in batches. Healthy and strong ones can be mixed with other fish species as parents.