Description

Abstract: Two experiments were conducted in 200-m2 earthen ponds at Asian Institute of Technology, Thailand, for 87 days to test the feasibility of an integrated pen-cum-pond system, which utilizes wastes from intensive culture of hybrid catfish (Clarias macrocephalus C. gariepinus) as nutrients for semi-intensive culture of Nile tilapia (Oreochromis niloticus). This integrated pen-cum-pond system enhances nutrient utilization efficiency, minimizes environmental impacts of pond effluents,

and gains extra fish production at low cost. Experiment 1 was designed to compare the integrated pencum- pond systems with natural and artificial water circulation. Six randomly selected 200-m2 ponds were partitioned by 1.0-cm mesh plastic net into two compartments: 1/3 of pond area (67 m2) for hybrid catfish and 2/3 (133 m2) for Nile tilapia. In experiment 2, one additional pond was partitioned by 1.0-cm mesh plastic net into three equal compartments with 67 m2 each. The mesh was not cleaned and thus partitions serve as three replicates for hybrid catfish culture alone (non-integrated system). Experiment 2 was designed to compare growth performance of hybrid catfish and effluent quality from intensive culture of hybrid catfish among the non-integrated system with hybrid catfish alone (non-integrated treatment) and the integrated pen-cum-pond systems (natural and artificial water circulation treatments) in the 67-m2 compartments. The nutrient budgets were also compared among the three culture systems. Sex-reversed all-male Nile tilapia were stocked at 2 fish/m2, and hybrid catfish at 25 fish/m2. Hybrid catfish were fed floating pelleted feed twice daily at rates of 3