First, the selection of wintering ponds
Overwintering ponds should be selected in a relatively regular shape, sheltered from the sun, have an area of ​​1000 to 1,500 square meters, and a water depth of 1.5 meters or more. It requires sufficient water for the pond, good water quality, convenient drainage and irrigation, and less silt at the bottom of the pond. There are many plants and no pollution.
Second, the overwintering time of the shrimp The overwintering time of the shrimp is usually late in the south and falls in the Yangtze River basin from December to April of the next year. It ends in most areas north of the Yangtze River from November to the end of April of the following year. During the winter, shrimp are generally lurking in the grass and rarely move. Therefore, in the overwintering pond, aquatic plants such as water peanuts and water lilies, or willows, can be set to provide a good warm wintering environment for the shrimps. After the winter, the plants sink by frost and can serve as overwintering and warming places for shrimps. Generally, 200 kg of aquatic plants or 30 kg of willow will be placed in each pond.
Third, the release of shrimp
1. Selection of Overwintering Green Shrimp Overwintering broodstock should be physically strong, large individuals, complete limbs, consistent specifications, and healthy and disease-free. General choice of broodstock body length in more than 5 cm, females should reach 200 ~ 500 / kg, males should reach 140 ~ 240 / kg, male to female ratio of 2:1 or 3:1. Overwintering prawns should be selected from September to December in September to December and have not grown to commercial specifications.
2. Overstock of wintering and prawn should be strictly kept clear before the stocking of holly prawns. When irrigating in ponds after clear ponds, screens should be set at the inlet to filter dense nets to prevent entry of predator organisms. Then put in the spent water plants and finally re-enter the overwintering shrimp. Green shrimp must be weighed, counted, and operated with water. During the operation, the shrimp cannot be piled up. The time of leaving the water must not exceed 5 minutes, nor should the wind blow or expose the sun. The size of the stocked shrimp in the same pond should be the same size. Give yourself enough time. The time of the lower pond is generally at the end of October. When the water temperature drops to 10-15°C, it is selected to be sunny. After transporting the shrimp, one day after the cultivation, the dead shrimp was removed and placed in the pond.
3. The stocking densities of overwintering green shrimp are higher than the stocking densities of winter holland shrimps. Generally, 15 to 25 kg of broodstock are stocked in a pond per mu, and 20 to 40 kg of larvae are replenished (a specification of 2000 to 3000 tails/kg).
Fourth, winter management
1. There is a clear seasonal change in the feeding intensity of feeding shrimp, which is mainly affected by the water temperature. When the water temperature falls below 8°C, it stops feeding and sneaked into the deep water area for winter. When the water temperature rises above 8°C, feeding begins. For this reason, during the entire wintering period of the shrimp, as long as the water temperature is above 8°C, it is necessary to insist on feeding in order to maintain its life and activities. The diet of shrimp should be plant-based. For example, shrimp eats rice, bran, bean cake, distiller's grains, etc., but it should be used with animal feeds, such as snails, small fish, fish meal, cocoons, etc. These are all delicious shrimps. After the above-mentioned several feeds are mixed in a certain proportion, the mixture is ground into a mortar, and a granular material with good stability in water or made of a binder is added. This will not only increase feed utilization, but also reduce water pollution. The bait should be selected for feeding on a sunny morning. The daily feed amount is about 3% of the shrimp body weight. The bait should be small and fine, not too much.
2. Adhere to the regular inspection of ponds during the wintering of the shrimps, we must adhere to regular inspections of the patrol ponds, mainly inspecting the overwintering conditions and changes in water quality of the shrimps, etc., and do a good job in prevention and control, escape prevention, and prevention of hostilities. During the severe winter season, it is also necessary to prevent the water body from freezing. Once it is frozen, it must be broken or drilled in time to prevent it from suffocating.
To do a good job of wintering shrimp is a very important part of the aquaculture production process. The overwintering of the shrimp is divided into two species: wintering of the young shrimp and wintering of the broodstock. The wintering of juvenile shrimp refers to shrimp breeding in August and September. By December, shrimps that have not yet grown to commercial specifications will need to pass through the winter to be reserved for stocking shrimp species in March and April of the following year. The overwintering of broodstock refers to the selection of broodstock to be used for breeding in the next year from commodity shrimp, allowing it to safely pass winter and intensify cultivation to meet the requirements for spawning and reproduction. The technical measures for the overwintering of shrimp ponds are described below.