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The survival rate of loach seedlings can reach more than 60%
Recently, some readers have come to the telephone to report that the survival rate of their cultivated loach seedlings is less than 20%, which cannot meet the needs of production and markets. He asked: What is the survival rate of muddy seedlings? Is there any way to increase the survival rate of seedlings? The reporter interviewed Professor Ling Feifei of the Fisheries Research Institute of Soochow University for information. Muddy natural breeding spawning rate is low, and the eggs produced are easily eaten by the relatives. It is very inconvenient to collect natural fertilized eggs and difficult to operate. What is the average survival rate of artificially cultivated loach seedlings? According to Ling Feifei, if the early feed clearance of muddy larvae and the dissolved oxygen in the early pond waters are well managed, the survival rate of culturing muddy larvae can reach about 60%. In order to prevent infertility from ingesting fertilized eggs during the artificial breeding of loach seedlings, the fertilized eggs should be timely collected and collected in a non-polluting, relatively large volume plastic bucket. The hatching density of fertilized eggs is 400 to 500 capsules/liter. An aerated stone is placed in the hatching tank and continuously inflated. At a water temperature of 20-25° C., the fertilized eggs can pass through the membrane for 25-30 hours, and the general emergence rate can reach 80%. Ling Feifei said that the cultivation of loach seedlings is generally conducted from May to June. It mainly promotes feeding and growth of muddy larvae that have already emerged from eggs. Before deciding to feed larvae, 500 kg of decomposed manure fertilizers and water are put into the larvae to cultivate natural feed. Normally, 150,000 to 200,000 muddy larvae per acre are put in. Quanchiposa soymilk is used as an opening material for muddy larvae on the one hand, and rotifers are cultivated on the other hand to provide natural rich feed for larval growth. The early stage of breeding muddy seedlings requires high dissolved oxygen in the water body. Generally, the amount of dissolved oxygen in the water body should reach 4 to 5 mg/L, and the transparency of the pool should be controlled to be more than 30 cm. Muddy larvae can usually be transferred to other ponds for cultivation after 7 to 10 days of cultivation. Recently, Wang Yuxin, director of the Shandong Provincial Institute of Freshwater Fisheries, presided over the project “The research on the artificial breeding and pollution-free breeding of large scale loachâ€. The survival rate of loach seedlings has reached more than 70%. Professor Wang Yuxin said in an interview with reporters that the project The cages are mainly used for spawning. After the end of spawning, the broodstock is removed and the cage is placed in a concrete pool with microfluidic water. Generally, the higher the water temperature, the higher the emergence rate of the loach. After the emergence of the loach, in addition to the zooplankton in the previous stage, the zooplankton may feed the egg yolk as an open feed. Generally after 4 to 5 days, the loach seedlings can be dispersed and cultured normally.