Evaluating the potential of aquaculture in the Hoa Binh reservoir with carrying capacity and water quality indices
Keywords:aquaculture, carrying capacity, Hoa Binh reservoir, water quality index
Not only does the Hoa Binh reservoir play essential roles in water storage for electricity generation and flood regulation, but also it has great potential to aid aquaculture production. Presently, aquaculture production sits at around 9,200 tons/year; however, a recent MARD circular (#16 in 2015) estimated that maximum production would approach 10,000 tons/year in the productive photic zone. This paper supports increased capacity towards a sustainable commodity production model by optimizing production levels and farming practices. To reach this goal, it is necessary to determine water quality parameters using the Relative Water Quality Index (ReWQI) and carrying capacity (CC) analysis. Data was obtained from 30 sites at upstream, midstream, and downstream sections of the reservoir during the 2019 dry and wet seasons. The results from the ReWQI reflected good water quality potential (rated between 92-100) for aquaculture. The total nitrogen (TN) and total phosphorus (TP) levels of 10,794.9 kg/day and 1,965.4 kg/day, respectively, indicate high biological productivity resulting in strong fish growth potential. CC analysis and overall water quality reflect the potential for sustainable and increased productivity to 22,730.4 tons/year, which is an increase in production of over 13,200 tons/year compared to the current period. To reach a higher yield of 40 kg/year/m3 within each cage (5,040 kg/cage/year), the corresponding increase in number needs to be 4,510 cages based on a common cage size of 126 m3 (6x6x3.5 m). In order to reach these future production goals, this work concludes that the local government should begin spatial planning decisions based on appropriate cage allocation and distribution with respect for regular monitoring of water quality and nutrient load capacity of the environment to reach sustainable aquaculture development.
Received 26 March 2021; accepted 21 May 2021