Stocking experience of tilapia in pond culture

The main results are as follows: 1. The selection of stocking specifications for adult fish culture is generally harvested in the same year, so the stocking specifications are generally 3cm to 10cm, with high survival rate, large commercial fish specifications and high economic benefits. At present, there are three main species specifications of tilapia cultured in China: early propagation, summer flower and overwintering fish. The main results are as follows: (1) early propagation refers to the breeding of parent fish from the end of March to the beginning of April in the overwintering pond and about 3 cm in mid-April and early May. It is released 1-1.5 months earlier than the normal breeding fish, and its average weight can reach 400-500 grams from the middle of May to the end of October. (2) the summer flower species of the current year refers to the fry that the overwintering parent fish were put into the breeding pond at the beginning of May and propagated for about 20 days, and the fry was bred into about 3 cm in mid-June and late June. This kind of fish species has a large number of production and low cost, and it can be released in that year, and commercial fish can be cultivated in that year, which is suitable for large-scale breeding of adult fish. (3) the overwintering fish species are the fry in the middle and late stage of last year, which are concentrated to 5cm and 10cm before overwintering, then move into the overwintering pond to spend the winter, and serve as adult fish species at the end of April or early May of the current year. Its specification is relatively large, the physique is good, the survival rate is high, if the stocking is reasonable, the commodity specification of more than 400 grams per tail can be reached at the end of August and the beginning of September of that year. Breeding overwintering fish species, the size of commercial fish is large, and according to market requirements, before a large number of tilapia are on the market, or even in summer, other fish products are listed in the off-season, and the price of commercial fish is high. The cost of overwintering fish species is relatively high due to overwintering conservation. At present, in order to meet the needs of providing bulk adult fish to export processing enterprises, more and more farmers have chosen this way. In addition, the climatic conditions are different in different places, and the stocking time varies greatly sooner or later, and there is no unified stocking model, so seedling specifications should be selected according to local conditions and market demand. 2. When the stocking time of seedlings requires that the natural water temperature is more than 18 ℃, sunny days can be selected. Generally speaking, fish species can be released at the end of March and the beginning of April in South China. 3. The stocking density is generally adopted to raise tilapia in ponds, and the stocking density of seedlings is generally 1000 to 1500 per mu, in addition, less than 100 silver carp and bighead carp are raised.