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Two Japanese prawn and a sea bream breeding technique
1 Selection, clearing and influent of aquaculture ponds (1) Choice and cultivating of aquaculture ponds with an area of ​​2 hm2 or more, a sandy bottom at the bottom of the pool, a sediment bottom, a water depth of 1.?8 m or more, and a steep wall The pond is suitable. In addition to the new pond, the aquaculture pond must be dredged. The method is to drain water from the pool and expose it to the ground for 15 to 20 days. The sludge is cleaned by mechanical or human labor. Immediately after dredging, the bottom of the pool is disinfected with quicklime or bleaching powder. The method is to enter the pool of 20 ~ 30cm, and then give lime 200 ~ 300g/m3 or bleaching powder 30 ~ 40g/m3 uniform spill, place 2 ~ 3d, the pool of water, repeatedly into the pool 2 ~ 3 times. For clear ponds, it is best to coat plastic film or straw curtains on the downtake pool wall to prevent the slope of the pool wall from sliding down to form a gentle slope; or to use a bamboo rod at the bottom of the pool with a 10 to 20 mesh screen to tighten the bottom of the net. The burial is solid and the mesh is 20~30cm above the highest surface of the culture to prevent wind and waves from damaging the jellyfish. (2) 30 to 40 days before flooding, 30 to 40 centimeters of water, 3 to 5 days, and then bleaching powder or bleaching solution to make the available chlorine reach 8g/m3 or more, after 2 to 3 days Disinfect the water and dry the bath for 3 to 5 days. Before the seedlings are released for 20-30 days, the water intake is 40-50 cm, and fertilizer and water are applied. The influent water must be filtered with a 60-80 mesh screen to prevent fish eggs and large enemy predators from entering the pool. Fertilizer can be properly fertilized according to its specific conditions, generally applied to fermented livestock manure 40-50kg/667m2, or urea 2kg/667m2, phosphate fertilizer 0.2kg/667m2, and then gradually add water to 100cm, through the application of fertilizer to make the pool water appear yellow-green or The tea brown is about 40cm in transparency. At this time, other animal food organisms such as cockroach, copepods, amphipoda, and horns are transplanted into the pool. 2 Seed Stocking (1) Before the release of the Japanese shrimp seedlings, the pool water should be tested so that the temperature, salinity, pH value, dissolved oxygen, etc. can be placed in the appropriate range of the Japanese shrimp seedlings before they can be planted. Release time: When the water temperature in the culture tank is continuously stable above 14°C, the Japanese shrimp seedlings can be stocked. The first batch of shrimp stocks in Japan is generally stocked in mid-April; the second batch of Japanese shrimp seedlings is generally planted in the middle and late July to early August after the first Japanese shrimp and sea bream are harvested. The density of seedlings: The first seedlings of Japanese larvae are stocked with 1 to 6 thousand seedlings of 0,700 to 7,000 tails per 667 square meters, and the second hatchback is stocked at 0.8 to 1 million tails per 667 square meters. If the pond area exceeds 6.67 hm2, the stocking density can be appropriately reduced. When the seedlings are released, the wind and warm weather are selected. At the upper air outlet, the temperature difference between the nursery pond water temperature and the culture pond is not more than 5°C, and the salinity difference is not more than 5 ‰. (2) Stocking time of jellyfish seedlings: The stocking time of jellyfish seedlings can be determined according to the growth status of Japanese shrimps, and must be released when the Japanese shrimps reach a body length of 3 cm or more. Under normal circumstances, the jellyfish seedlings will end at the end of May. It is better to stock up in mid-June. Stocking densities: 200 to 667 m2 for juveniles with an umbrella size of 1 to 1.5 cm; 100 to 150 to 667 m2 for animals with an umbrella size of 2 cm or more. Transportation of sea lice seedlings: Sea larvae seedlings used in the transport process vary depending on the temperature and distance. Short-distance transport can use smooth internal walls without oxygenation. When transporting long distances, polyethylene double bags should be used. Oxygenation method, bagging density generally umbrella diameter 1 ~ 1.5cm of juvenile 800 ~ 1500 head / L, umbrella diameter 2cm above 500 ~ 1000 head / L, if the transport time exceeds 10h, should use ice cooling And reduce the bagging density to ensure the survival rate. When sea bream seedlings are stocked, they should choose warm weather with no wind or small wind. The location is selected at the upwind outlet to prevent the jellyfish seedlings from excessively concentrating on the edge of the pool at the bottom of the breeze to cause death. 3 Aquaculture management (1) Water quality management During the entire culture process, a stable algae phase with a transparency of 40 to 50 cm and a pH of 7.8 to 8.6 was observed. In the early stage of cultivation, the main fertilizer is water, and water is added 10~15cm every 4~5d. After the Japanese prawns grow to 5cm, the pool water is added to 1.5m or more; in the middle period of cultivation, the previous "fat water" is changed to "living water". The amount of water reaches 10% to 15%; the water level will be appropriately increased in the later period of cultivation depending on the water quality, and the water depth will be added to the maximum water level. Pay attention to the flow of water when entering or draining. Do not be too rushed to avoid damaging the jellyfish. (2) Feed pre-feeding is mainly based on the basic food organisms in the pool, supplemented by feeding small fish, shrimps and feeds, and peanut cakes; in the middle and late period, it is mainly supplemented with bait, supplemented by broken clam meat, and Feeding 2 times, usually at 18 to 19 o'clock in the evening, accounting for 70% of the daily feeding amount, feeding once in the morning, accounting for 30% of the daily feeding amount. Under conditional conditions, 80 to 120 mesh screens can be used to catch some copepods, cladocera, amphipoda, and crustacean larvae and adults in a waste water pond and put them into aquaculture ponds to feed the jellyfish. In order to promote the rapid growth of sea lice, especially at a water temperature of about 24°C, it is the optimum water temperature for the growth of sea otters. Sea otters grow at a particularly fast pace and require a particularly large amount of food. (3) Observe the daily water temperature, salinity, pH, and transparency at regular intervals on a daily basis, record well, and swim the pool several times in the morning and evening. Observe the activities and feeding conditions of Japanese shrimps and sea otters in the strong winds and heavy rains. The hot weather must pay attention to strengthening the patrol pool, especially when there are strong winds, it is necessary to patrol the pool in time so that sea otters stormed by the storm can be moved to the deep water in the pool to prevent the sea otters from dehydrating by the poolside for a long time. Caused death. 4 Harvesting (1) Harvest of the first Japanese shrimp When the Japanese shrimp grows to 60-70 tails/kg, they can go out of the pond, generally from late June to late July. (2) The harvest of sea bream depends on the size of the sea bream and market conditions, generally from late July to early August. (3) Harvesting of the second Japanese shrimp can timely arrange the harvest time according to the climate and market conditions. 5 Growth and survival rate (1) The survival rate of shrimp in Japan is generally up to 30% and the specification is 60 to 70 tails/kg. (2) For sea lice, the survival rate is generally more than 20%, and the average body weight can reach more than 7.5kg. 6 Summary Japanese shrimp and jellyfish polyculture, in the current sluggish shrimp breeding industry, undoubtedly opened up a new way, due to the rapid growth of sea bream, short cycle, the market is popular, while the sea bream with copepods, Cladocera The larvae of species, amphibians, crustaceans, shellfish and other zooplankton are bait, so the cost of breeding is very low.