THE CURRENT WATER ENVIRONMENT QUALITY STATE OF THE CAGE FISH FARMING AREA IN HOA BINH AND THAC BA LAKE

Abstract

Hoa Binh and Thac Ba Lake play crucial roles in the economic development of the northern provinces. Besides the hydropower production and tourism activities, cage fish farming in the two lakes has seen significant development. This study was conducted to assess the water environment in the fish farming areas of Hoa Binh and Thac Ba Lake from 2019 to 2022, aiming to propose management measures to enhance the efficiency of aquaculture. The water quality parameters including temperature, pH, dissolved oxygen (DO), NH₄-N, PO₄-P, NO₂-N, S^2-, COD, phytoplankton, total Streptococcus bacterial density, and total coliform in the water were evaluated from April to October. The results indicated that COD, total Streptococcus, and total Coliform showed an increase trend from June to July. The concentration of NH₄-N, PO₄-P, and NO₂-N tended to increase over the years. The parameters NH₄-N, PO₄-P, NO₂-N, Coliform, Total Streptococcus, and pH negatively impact the Water Quality Index (WQI) of the two lakes. Aquatic feed and household waste management should be considered to minimize impacts on water quality.