Trophic model and technical-economic aspects of cove aquaculture in Tri An Reservoir of Vietnam | |
| Author | Vu Cam Luong |
| Call Number | AIT Thesis no. AQ-00-27 |
| Subject(s) | Fish-culture--Vietnam Aquaculture--Vietnam |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. AQ-00-27 |
| Abstract | Fish culture in coves makes use of areas that are alternately flooded and exposed. These areas are separated from the main part of the reservoir by a barrier net and are used for the culture of food fish or catching the wild fish. An attempt to construct a trophic model of cove aquaculture in Ma Da Cove of Tri An Reservoir, was made using the ECOPATH 3.0 approach and software (Dalsgaard and Oficial, 1998). The energy flows through the system, which includes among other components, five fish species (Cyprinus ca1pio, Aristichthys nobilis, Hypophthalmichthys molitrix, Ctenophmyngodon idella, and Oreochromis sp.) were quantified. The fish stocking density was 0.51 fish m·2 and there were no any additions of food or manure. In terms of natural food sources, Ma Da Cove had plankton biomass of 0.61-1.24 gDW m·2 , zooplankton biomass of 0.2-0.69 gDW m·2 and benthos biomass of 1.54-1.6 gDW m·2 . Besides, the system had a very high import of terrestrial plants (373.72 gDW m·2 year"1) that are produced on the temporalily inundated area. The trophic model shows that the system has very few trophic levels, and the bulk of flows are at trophic level II (the herb ivore level). The model predicts a very high rate of zooplankton and phytoplankton that are consumed by fish, therefore an inadequate condition of zooplankton food may occur in the system. The highest biomass and production of fish group are found at common carp and bighead carp (1.8-1.9 gDW m·2 and 3.5-3.6 gDW m·2 year"1, respectively). The survey on technical-economic aspect of cove aquaculture act1v1t1es was also carried out to understand how well can the ecological model, designed in this study, be applied to cove aquaculture currently practiced in Tri An Reservoir? The result shows that cove aquaculture in Tri An Reservoir can be classified into 3 categories, i.e., cove aquaculture with and without mixing the predatory fish, and the combination with cove fish ing. There were rather low of the survival rate and production of cultured fish in coves (I 0-45% and 43 8-697 kg ha·1 year"1, respectively). Cove aquaculture is profitable to practice in Tri An Reservoir. However, there were the low profit and profit margin for cove aquaculture without mixing the predatory fish (3.48-7.17 million VND year"1 and 8.9- 15.2%, respectively). The impressive profit and profit margin were found at cove aquaculture with mixing the predatory fish (12-439.3 million VND year"1 and 13.7-52.4%, respectively). These coves make foll use of all food resources and ecological niches when the small low-value fish that are abundant in reservoir feeds the predatory fish. Therefore besides the economically important fish, some high-value predatory fish which less harm other stocked fish should be introduced into the system. E.g. marbled sleeper (Oxyeleotris marmolata), climbing perch (Anabas testudineus) and bronze featherback (Notopterus notopterus). Besides, the freshwater prawns (Macrobrachium spp.) should be considered as the potential species to be stocked in coves for a better utili zation of all food resources there. |
| Year | 2000 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. AQ-00-27 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Aquaculture and Aquatic Resources Management (AQ) |
| Chairperson(s) | Lin, Chang Kwei; |
| Examination Committee(s) | Yakupitiyage, Amararatne;Rubin, John; |
| Scholarship Donor(s) | Danish International Development Assistance (DANIDA);Aqua Phase II; |
| Degree | Thesis (M.Sc.) - Asian Institute of Technology, 2000 |