Description

Abstract: An experiment was conducted for 150 days at Cantho of Vietnam to determine the appropriate stocking density of caged climbing perch (Anabas testudineus) in Nile tilapia (Oreochromis nilocticus) ponds, to assess the economic and environmental benefits of this integrated cage-cum-pond culture system. One of the 4m3 cage was suspended in each of twelve 100-m2 earthen ponds, and three ponds of same size served as control without cages. Climbing perch fingerlings 9 g in size were stocked at 50, 100, 150, and 200 fish/m3 in cages, while Nile tilapia fingerlings of 10g size were stocked at 2 fish/m2 in all fifteen ponds, giving caged climbing perch to open-pond Nile tilapia ratios of 1:1, 2:1, 3:1 and 4:1, respectively. Caged climbing perch were fed commercial pelleted feed (26-28% crude protein) at rates of 5%, 3% and 2% body weight per day during the first, second and the remaining months, respectively. The control ponds were fertilized weekly with urea and TSP at 28 kg P/ha/week, while no fertilizers were applied in the treatment ponds.

Survival of climbing perch in the highest density treatment (97.1%) was significantly lower than that in other treatments (99.3-99.6%; P<0.05), while there was no significant difference in survival of Nile tilapia, ranging from 72.5% to 87.2% (P>0.05). Final mean weights of both climbing perch and Nile tilapia were not significantly different among all treatments, ranging from 19.5 to 20.5 g and from 111.5 to 133.9 g, respectively (P>0.05). Total Harvest weight of climbing perch, ranging from 400 to 15.2 kg/cage, increased significantly with increasing stocking density (P<0.05), while total harvest weight of Nile tilapia was highest in the 150 fish/m3 treatment (22.7 kg/pond), immediate in other cage treatments (19.0-20.7 kg/pond), and lowest in the control (15.8 kg/pond; P<0.05). The combined total weights of both climbing perch and Nile tilapia in the high density treatments (35.0 kg/pond in 150 fish/m3 treatment and 35.8 kg/pond in 200 fish/m3 treatments) were significantly greater than those in the low density treatments (23.0 kg/pond in 50 fis/m3 treatment and 28.2 kg/pond in 100 fish/m3 treatments; P<0.05). FCR of climbing perch in all treatments was very high, ranging from 5.05 to 6.00. FCR was lowest in the 150 fish/m3 treatment, intermediate in the 100 and 200 fish/m3 treatment, and highest in the 50 fish/m3 treatment (P<0.05). The results indicate that caged climbing perch to open-pond Nile tilapia ratio of 3:1 was the best. Further research in feed protein level and feed strategy should be conducted.