Tilapia–Shrimp Polyculture in Negros Island,Philippines: A Review |
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| Authors: | Philip S Cruz Merlina N Andalecio Remedios B Bolivar Kevin Fitzsimmons |
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| Institution: | 1. Cruz Aquaculture Corporation, 158‐C, Philsugin Road, Singcang, Bacolod City 6100 Philippines;2. Institute of Fisheries Policy and Development Studies, University of the Philippines Visayas, Miagao, Iloilo 5023 Philippines;3. Freshwater Aquaculture Center/College of Fisheries, Central Luzon State University, Science City of Mu?oz, Nueva Ecija 3120 Philippines;4. Environmental Research Laboratory, Department of Soil, Water and Environmental Science, University of Arizona, 2601 E. Airport Drive, Tucson, Arizona 85706 USA |
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| Abstract: | Tilapia–shrimp polyculture has played an important role in current efforts to control luminous bacterial disease caused by Vibrio harveyi. At present, green water technology is most extensively used by shrimp farmers in Negros Island in the central Philippines. While the contribution of tilapia as a biomanipulator is highlighted in the literature, the mechanism of action is not well understood. Data were gathered from shrimp ponds practicing two production systems: (a) green water system (probiotics + tilapia) and (b) closed/semiclosed system (probiotics alone). There was no difference between luminous Vibrio count (P < 0.05) in both systems, and water quality was found to be similar (P < 0.05). Because the green water system uses a bigger reservoir to raise the tilapia biomass, the net shrimp production was lower. In terms of direct cost of production, however, the green water system was 10–15% lower than the closed/semiclosed system because of significantly less aeration required. The polyculture maintained a more stable plankton environment during the early months of culture, which increased survival of shrimps. Various pathways are presented for the control of luminous bacterial growth in polyculture ponds: (a) fish feeding on organic wastes and conversion to feces; (b) selective fish foraging to increase the dominance of beneficial phytoplankton; (c) bioturbation of pond sediments; and (d) release in the water column of antimicrobials, fungi, or competing bacteria from the skin and gut mucus of tilapia. |
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