Economic and ecological benefits of annually two-cycle farming method of GIFT tilapia with in-pond raceway system

To achieve an efficient utilization of pond aquaculture system and reduce the risk of cultivation, we investigated the annually two-cycle farming method of GIFT tilapia  (Oreochromis niloticus) with in-pond raceway system. In the first breeding production, we kept the fish [(36.6±2.8) g] in two raceway for 122 d with the densities of 183 ind·m⁻² and 274 ind·m⁻², respectively. In the second breeding production,we kept the fish [(185.2±15.8) g] in two raceway for 100 d with the densities of 154 ind·m⁻² and 215 ind·m⁻², respectively. Meanwhile, Macrobrachium rosenbergii, Hypophthalmichthys molitrix and Aristichthys nobilis were cultured around the pond. Then we evaluated the water quality, aquaculture results and breeding benefits in the aquaculture process. The results show that the survival rate of GIFT tilapia was 83.38%; the feed coefficient was 1.12; the aquaculture yield was 24 107 kg in the first breeding production. While in the second breeding production, the survival rate was 93.35%; the feed coefficient was 1.17; and the aquaculture yield was 25 730 kg. The yields of M. rosenbergii, H. molitrix and A. nobilis were 2 012 kg, 1 789 kg and 801 kg, respectively. For the breeding benefits, the average investment and income were 452 566 Yuan per square hectare and 655 099 Yuan per square hectare, respectively, with a profit of 202 533 Yuan per square hectare and a return rate of investment of 44.75%. It is indicated that the annually two-cycle farming method with in-pond raceway system is effective for GIFT tilapia breeding, which can reduce the incidence of Streptococcus and improve the breeding efficient utilization.