Changes in basic water environmental parameters of the water intake of brackish water shrimp farming in Northern Vietnam period 2017-2021

This study synthesised and analysed water environmental parameters data of water supply of brackish water shrimp farming in Northern Vietnam over 5 years from 2017 to 2021 to find out the changing patterns of the parameters, thereby making appropriate recommendations for stakeholders. There were 7 analysed and evaluated water environment parameters, including water temperature, dissolved oxygen (DO), salinity, pH, alkalinity, chemical oxygen demand (COD), nitrite (N-NO2), with monitoring frequency of 2 times/month, 10 months/year at 13 monitoring locations for brackish water shrimp farming in 6 provinces: Nam Dinh, Nghe An, Ha Tinh, Quang Binh, Quang Tri, and Thua Thien Hue. Water temperature was low at the beginning of the year, gradually increased to the highest level in June, then gradually decreased to the end of the year. The temperature fluctuated strongly at the beginning and end of the year and tended to increase gradually from the North to the South. DO tended to decrease from the beginning of the year to the end of the year. Salinity was lower in the rainy season, especially in Nghe An and Quang Tri, compared to the others. The pH and alkalinity levels were suitable for brackish shrimp farming. COD in Ha Tinh and Nam Dinh, NO2 in Nam Dinh were often high, indicating that the supply water was contaminated with organic matter and needed a long-term solution.