Detailed explanation of key technical points for flood-avoidance aquaculture, reducing losses from flood disasters

For small lakes and ponds in areas along lakes and rivers, after inundation and flood disasters occur, two technical models are usually adopted in aquaculture production: market-size fish farming and fingerling farming. The key technical points are introduced as follows:
　　
A. Market-size fish farming technical model
1. Basic conditions. After the main flood season, when the water level begins to recede, dikes and pond embankments that have not been destroyed or can be repaired in time should be repaired promptly, and the water depth should be maintained above 1 m.
2. Clearing and disinfection. Install fish-blocking facilities in lakes and reinforce dikes; check the amount of fish in stock, harvest market-size fish for sale, retain undersized fish for redistribution, and disinfect ponds with 1 ppm bleaching powder.
3. Stocking of fry and fingerlings
(1) Stocking time: after the main flood season, once the water level begins to recede and stabilizes, generally in mid-to-late July.
(2) Stocking size: the body length of the main cultured species should be above 20 cm, and that of the secondary cultured species above 10 cm. Strive to sell large-size commercial fish as early as possible.
(3) Stocking species and quantity: in terms of species and quantity, supplement 60% of the fish quantity; through appropriate thinning, promote rapid fish growth, increase the size at harvest, and additionally polyculture 500-1000 large-size grass carp and late-summer fry per mu to prevent a shortage of large-size fingerlings by the end of the year.
4. Feeding and fertilization. Sufficient feeding and rational fertilization are key technical measures for successful farming. If farmers want to catch 1-2 batches of market-size fish for sale from September to early November, they must increase the feeding amount and frequency of compound feed. Generally, the daily feeding amount is 5-6% of the body weight of the fish in the pond, and the daily feeding frequency is 3-4 times. Feeding should follow the "four fixed" principle, and the feed type and feeding amount should be adjusted at any time according to water temperature, weather, water quality, and growth stage. Pond fertilization should be mainly inorganic fertilizer, supplemented by organic fertilizer, and the transparency should be kept within 40 cm.
5. Disease prevention and control. After the flood, disinfect immediately to kill external pathogens. Every 20-30 days, carry out one prophylactic medication treatment; insecticides and fungicides such as trichlorfon and dibromohydantoin should be used in rotation. Every 30 days, administer one course of oral medication. When diseased fish are found, diagnose and treat them promptly.
6. Daily management. Persist in patrolling the pond morning and evening, observe fish feeding and growth, check inlet and outlet facilities, and remove floating grass debris; deal with problems promptly when found.
　　
B. Fingerling farming technical model
1. Basic conditions. Fingerling farming can be carried out in waters that have been flooded for a long time and where large numbers of fish have escaped. Generally, lakes or ponds are selected whose earthen embankments can be repaired promptly and which can be drained dry.
2. Pond clearing and disinfection. Apply 150-200 kg of quicklime per mu to disinfect the whole pond and kill pathogens and wild miscellaneous fish in the pond. Install fine-mesh netting at the inlet and outlet to prevent wild miscellaneous fish from entering.
3. Stocking of fry and fingerlings
(1) Stocking time: fry can be stocked 10-15 days after pond clearing and disinfection.
(2) Stocking size: large-size summer fingerlings, with a size above 3 cm.
(3) Stocking species and quantity: the total stocking amount per mu is 6000-8000 fish, with one species as the main cultured species, accounting for 70% of the total stocking amount, and 2-3 secondary cultured species accounting for 30% of the total stocking amount.
4. Feeding and fertilization. The daily feeding amount of feed is 6-8% of the body weight of the fish in the pond, and the daily feeding frequency is 2-3 times. Pond fertilization should be mainly organic fertilizer, supplemented by inorganic fertilizer, and the transparency should be kept within 30 cm.
5. Disease prevention and control. Every 20-30 days, carry out one prophylactic medication treatment; insecticides and fungicides such as copper sulfate, trichlorfon, and dibromohydantoin can be used in rotation. When diseased fish are found, diagnose and treat them promptly.
6. Daily management. Persist in patrolling the pond morning and evening, observe fish feeding and growth, check inlet and outlet facilities, regulate water quality, promptly remove dead and diseased fingerlings, and deal with problems promptly when found.