Seed production and breeding techniques of Oreochromis tilapia

mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA">25-30℃, , can cross-breed once every 30-50 days. The quality of the broodstock breeding tank, directly affects the spawning, hatching and survival rate of the fry. (2)Area and water depth:The breeding pond area is generally 0.5-2 acres. (3)Shape and soil quality:The best shape of the breeding pond is an east-west rectangle, There should be a shallow beach beside the pondBefore the broodstock are released, the breeding tank must be cleaned and disinfected , to create excellent living environment conditions for the broodstock , which is conducive to the reproduction of the broodstock. Commonly used drugs for clearing ponds include quicklime, bleaching powder, etc. , Among them, quicklime is the best , which can not only kill wild fish, harmful organisms and pathogens in the fish pond , but also act as fertilizer and water. The method of clearing the pond is to drain the pond water, leaving 5-10 centimeters of water at the bottom of the pond, use quicklime 60-75 kg per acre3, apply basal fertilizer
Generally, 500-600kg , or green manure 400-500kg are applied per mu. The broodstock used for cross breeding must be carefully selected, to ensure better hybrid vigor. Nile tilapia--The body color is yellow-brown,There are nine vertical black stripes on the side of the body,The terminal edges of the dorsal and caudal fins are black, There are obvious black vertical stripes on the caudal finOlia tilapia--The body color is blue-purple-gray, There are 9-10 vertical black stripes on the side of the body, The terminal edges of the dorsal and caudal fins are redThe third step is to select individuals that grow quickly, are large, strong, and have no injuries or diseases, Generally, the individual weight of Nile tilapia female fish is required to be 150 grams or more, to , often causes the degeneration of parent fish, and the growth of offspring slows down, and the size of sexual maturity becomes smaller. The female fish has three openings in its abdomen, namely the anus, genital pore and urinary pore. 3, stocking time
The broodstock should be stocked in sunny and windless weather , and it is better to stock the broodstock at one time , so that the spawning time of the broodstock can be concentrated , and the seedlings will be consistent , which is conducive to seed cultivation. When stocking broodstock, the ratio of female and male broodstock should be appropriate, Generally 3:1 or 4:1 is better250-500g/ tail of female broodstock 600-750 tail, if the male and female are 3∶1 group(三) Broodstock Breeding
Fertilization should follow the principle of small amount and frequent application, Generally, fermented manure 100-200kg or green manure 200-300kg should be applied per acre every 5-6 days. In order to promote the gonad development of broodstock fish, artificial feed should be fed 1-2 times a day. (Four) Master the spawning date of broodstock
When the water temperature is around 20℃, the parent fish will begin to come into estrus , It is common to see male fish digging nests with mud in their mouths in the shallow water near the pool. When the water temperature is 25℃, , you will see a small group of swimming fry , in about 15 days. At this time, you need to catch the fry in time. Currently, the better way to catch seedlings is to use a ?? net or a small trawl net , to drag around the pond. Total mantissa=Number of cups×Mantissa of each cup.