CRSP Research Report 04-201
Waste Recycling in Fish Pond Culture through Integrated Culture Systems
Yang Yi and C. Kwei Lin
Aquaculture and Aquatic Resources Management,
School of Environment, Resources and Development,
Asian Institute of Technology,
P.O. Box 4 Klong Luang, 12120 Pathumthani, Thailand
James S. Diana
School of Natural Resources and Environment,
University of Michigan,
Ann Arbor, Michigan 48109-1115, USA
Two new culture strategies, have been developed to recycle feeding waste derived from intensive aquaculture within a single pond, enhance nutrient utilization efficiency, reduce the nutrient contents in effluents discharged from intensive culture ponds, and mitigate eutrophication in receiving waters.
In the integrated cage-cum-pond culture system, high value species are stocked in cages suspended in ponds, and filter-feeding species are stocked in open water outside the cages. While in the integrated pen-cum-pond culture system, high valued species and filtering-feeding species are segregated by plastic netting, which partitions a pond into two compartments. High- value species in both systems are fed a high protein diet, while the filtering feeding species depend solely on natural foods generated from feeding wastes.
In the integrated culture systems, nutrients contained in wastewater of intensive fish culture can be effectively reused by filtering-feeding species, giving compatible yields with those achieved in organically or inorganically fertilized ponds. The integrated culture systems recycle wastes from intensive culture into semi-intensive culture, thereby reducing the nutrient input for pond fertilization, and minimize the impacts
of pond effluents on environments. The integrated culture systems can also be used in polyculture ponds to confine costly high protein diets to the high valued species to achieve higher economic returns. The integrated culture systems can be adapted by small-scale farmers, especially suitable for low capital investment.
This abstract is excerpted from the original paper, which was published in the Proceedings of the Third World Fisheries Congress: Feeding the World with Fish in the Next Millennium‹The Balance between Production and Environment. American Fisheries Society, Symposium 38, Bethesda, Maryland, pp. 265-270.
under normoxic conditions were higher than the ones recorded under hypoxia, except for those of 17,20 P in males. Males responded positively to the hormonal treatments, and the concentration of spermatozoa was 10.5 ± 0.8 109/mL under both oxygen conditions. Hypoxia resulted in significantly lower survival of embryos (17.3 ± 28%) in comparison to normoxic conditions (68.5 ± 25%). Moreover, larval deformities were found when exposed to hypoxia (91.6 ± 6%). During embryonic development of this species 4 mg/L of oxygen is tolerated at
-27 C without negative impact. We conclude that despite the highly adaptable nature of adult pacu to environmental hypoxia, oxygen concentrations below 4 mg/L severely impacted survival of embryos.26R>
This abstract is excerpted from the original paper, which was in Journal of the World Aquaculture Society, 34(4):441449.
CRSP Research Report 04-202
Stocking Densities of Nile Tilapia in Tilapia-Shrimp Polyculture Under Fixed Feeding Regime
Yang Yi and Potjanee Clayden
Aquaculture and Aquatic Resources Management
School of Environment, Resources and Development
Asian Institute of Technology
Pathum Thani, Thailand
Kevin Fitzsimmons
Environmental Research Laboratory
University of Arizona
Tucson, AZ, USA
An experiment was carried out in nine 200-m2 earthen ponds at the Asian Institute of Technology, Thailand, to investigate the growth performance of Nile tilapia (Oreochromis niloticus) and shrimp (Penaeus monodon) and water quality in different stocking combinations of tilapia-shrimp polyculture under fixed feeding regime. There were three treatments in triplicate each: shrimp alone at 30/m2 (monoculture, control); shrimp at 30/m2 and Nile tilapia at 0.25/m2 (low tilapia density polyculture); shrimp at 30/m2 and Nile tilapia at 0.50/m2 (high tilapia density polyculture). The fixed same feed ration for all ponds was determined by a feeding table during 75-day culture period.
Results showed that the low tilapia density polyculture resulted in significantly higher shrimp yield than the monoculture and high tilapia density polyculture (P < 0.05). FCR of 1.44 in the low tilapia density polyculture was significantly better than those (1.73 and 1.69) in both monoculture and high tilapia density polyculture, respectively (P < 0.05). Nile tilapia showed fast growth (4.64-4.70 g/fish/day). There was no significant difference in growth and survival of Nile tilapia between the low and high tilapia density polyculture (P > 0.05), while fish yields were significantly higher in the high tilapia density polyculture than those in the low tilapia density polyculture (P < 0.05).