Shrimp Farming Experience in High-Temperature Season: Feeding and Management
In the high-temperature season, the weather is hot, sunlight is intense, air temperatures are high, and water quality is poor, which affects the shrimp's foraging and molting growth, and can also easily cause disease and death. Based on the practical experience of 21 large shrimp farming households including Liang Chunlin and Mu Youbin in Pulandian City, Dalian, located at the junction of the Yellow Sea and the Bohai Sea, the following four essentials should be followed to do a good job in shrimp feeding and management.
1. Water control of temperature and oxygen enrichment must be carried out
As water temperature rises and the shrimp grow, the water depth must be continuously increased. Especially in the middle and late stages of farming, the water level must be raised to 1.8 m to 2 m, and during the high-temperature period it must be maintained above 2.2 m. For this reason, during spring tides, water should be exchanged once a day; during neap tides and dry periods, mechanical drainage and irrigation should be used so that the water exchange volume reaches about 50%. During the high-temperature period, complete drainage and complete refilling should be carried out. This can effectively control the water temperature below 30°C, bring water transparency to 35 cm, and stabilize dissolved oxygen at about 5 mg/l, so as to facilitate vigorous feeding and rapid growth, high quality and high yield in shrimp. When changing water, prevent the intrusion of live organisms carrying explosive shrimp viruses; it is best to filter the water with 60-mesh netting at the water inlet.
2. Bait must be fed in stages
When the shrimp body length is more than 4 cm, the main feed should be low-value small shellfish bait such as snails and clams, feeding 6 kg to 8 kg per 10,000 shrimp per day; when the shrimp body length is 8 cm, feed 50 kg per 10,000 shrimp per day; when the shrimp body length is 12 cm, feed 100 kg per 10,000 shrimp per day. If small shellfish bait is insufficient, compound feed may be fed. When the shrimp body length is more than 4 cm, feed 1.5 kg per 10,000 shrimp per day, and thereafter for every 0.5 cm increase in shrimp body length, increase the daily feed by 0.3 kg to 0.5 kg per 10,000 shrimp; when the shrimp body length is more than 10 cm, increase the daily feed by 0.7 kg to 0.8 kg per 10,000 shrimp. If using ice-fresh small trash fish, replace 1 kg of compound feed with 2.5 kg of ice-fresh small trash fish.
Shrimp have the habit of lying low by day and emerging at night, being active frequently at night with a strong appetite, and hiding by day with a weakened appetite. Therefore, bait should be fed twice, before sunrise and after sunset, with 1/3 in the morning and 2/3 in the evening. Feed should be spread on the platforms around the shrimp pond so that all shrimp can eat it. When feeding, adhere to the principle of "four less, four more, two no-feeding." "Four less, four more" means feed less in the early growth stage of shrimp and more in the later stage; feed less in the morning and more in the evening; feed less during neap tides and more during spring tides; feed less when shrimp are molting in large numbers and more during normal growth. "Two no-feeding" means do not feed spoiled bait, and do not feed in ring ditches and deep-water areas.
3. Shrimp diseases must be strictly guarded against
In the high-temperature season, shrimp have poor activity and feeding ability, the body's metabolic level declines, and in addition the water environment deteriorates and pathogenic organisms breed, making shrimp diseases easy to occur. Therefore, shrimp disease prevention and control work must be done well. First, note that the feeding amount should not be too much or too concentrated, so as to avoid bait spoiling and becoming foul. In particular, fresh and live bait is extremely prone to spoilage in high temperatures. To reduce water pollution in shrimp ponds, water should be changed frequently. Second, reasonably regulate shrimp population density to maintain a certain activity water area for the shrimp.
4. Shrimp floating-head death must be prevented
In the high-temperature season, pond patrols should be carried out every morning and evening to observe shrimp growth activity and residual bait conditions, and determine the variety and quantity of bait to be fed that day. When shrimp are molting in large numbers, feed some high-protein compound feed to prevent cannibalism. At midnight and before dawn, oxygen in the pond water drops to its lowest point, which is the dangerous time when shrimp are most prone to floating-head death. If phenomena such as mysid shrimp and white shrimp floating at the surface and small trash fish gathering toward the pond edge are found (these are signs of shrimp floating-head), the aerator must be started promptly or water must be exchanged.