Release technique of tilapia seedlings in spring

The plan for the year lies in spring. After mid-March, the air temperature and water temperature in South China have gradually picked up and stabilized; the majority of farmers are in the preparatory stage of releasing tilapia fry.

I. matters needing attention in throwing seedlings

The relevant preparatory work should be done before putting in the seedlings. After the fish ponds are cleaned, it is best to sun the ponds for a few days and use quicklime to disinfect and sterilize; close-eye screens or cages should be used to block the inflow of wild miscellaneous fish and other rubbish from the outside world; follow the principle of "growing up in shallow water and deep water". Generally, 80cm~100cm is put into the water to release the seedlings, and then gradually increase the depth of the water. Prepare the air thermometer and water thermometer, and measure the air temperature and water temperature frequently. Only when the weather is stable and the water temperature rises above 20 ℃, and will continue to stabilize or rise, can you release the seedlings; 3-5 days before the release, the water body is insecticidal and sterilized once, and after the efficacy disappears, a small number of fish fry are selected to test the water, and only when the safety is confirmed can the fry be released as planned.

Selection of tilapia fry: reasonable selection of tilapia strains suitable for culture according to different culture environment and culture mode (such as Orney strain, Gifu strain, etc.). Tilapia seedlings with stable quality and regular production sites should be selected for release. Good at observing fish fry, fish fry with strong physique, no mechanical damage, swimming quickly, and can quickly swim in the same direction after slightly stirring by hand in the basin is the preferred healthy fish fry.

Try to avoid mechanical damage in the process of operation, and do a good job of sterilization and disinfection in the process of packaging and transportation. After the seedlings arrive in the pond, pay attention to the constant temperature and then put them into the pond to avoid stress as far as possible.

II. Suggestions on aquaculture management

1. Take regular spot checks and pay attention to the killing of rotifers, oblique tube worms and the third generation of insects, based on the principle of killing insects first and then sterilization, so as to avoid the breeding of pests and water mildew, and invade tilapia seedlings.

2. Pay attention to the regulation of water quality and keep the water quality "cool, tender and smooth".

Microbial preparations such as quicklime or "enzyme bacteria" are used to regulate and maintain the water quality; pay attention to detect the contents of pH value, nitrite and ammonia nitrogen in the water, do a good job of degradation and regulation in time, and reasonably supplement base fertilizer. balance the reproduction of beneficial algae and bacteria in the water; with the growth of fish fry, gradually inject new water.

Feed reasonably to ensure the healthy growth of fish fry and improve the survival rate of fry. In the fry stage, high-protein and high-quality powdered feed is selected as the main feed; on the basis of a small number of meals, feeding is carried out regularly, qualitatively and quantitatively in proportion; in general, a long-distance feeding site should be selected in the fry stage to ensure uniform feeding and average growth rate of fry; timely and appropriate addition of antibacterial, liver protection and health care drugs to the feed to further improve the disease resistance and immunity of fry.

Pay attention to the driving away and cleaning of snakes, birds and frogs to prevent the above-mentioned fish natural enemies from encroaching on tilapia fry and reduce the loss of fry.

Pay close attention to the weather conditions and do a good job in aquaculture management according to the actual situation.