The hapa net nursing system is used for monosexing tilapia fry with the aim of increasing the efficiency of monosex fry production. In the present study, the production of SRT (Sex Reversed Tilapia) of Oreochromis niloticus and red hybrid Oreochromis sp. was investigated, using hapa net and hapa-free systems. The ranges and averages of total length and body weight, percentage of monogamy and survival of black tilapia and red hybrid tilapia fry were compared in two nursing systems.
Tilapia breeding has developed in the world and it is necessary to produce enough fry to meet the demand of breeders. The production of tilapia fries is a basic requirement for the tilapia culture industry and it is necessary to optimize the production of fries to increase the profitability of the tilapia hatcheries.
In the present study, the production fries of Nile tilapia, Oreochromis niloticus and hybrid red Oreochromis sp. was investigated, using tank and hapa systems. The results showed higher significant difference in the length and weight of fish in the hapa-free tanks, by t-test (p <0.05) but much isometric fries and more survival in the hapa system. SRT were similarly 100% monosexed in both systems. Also, the means of total length, body weight and survival of hybrid red tilapia were significantly higher than Nile tilapia fries, by t-test (p <0.05). Producing SRT fries in tank system with hapa tended to more isometric fries and appropriate survival, however fries produced in tanks without hapa had higher total length and body weight.