The Study for Proposing Technical Guidance on Identifying the Causes and Economic Losses Caused by Mass Fish Die–off to Resolve Environmental Conflicts

Mass Fish Die–off (MFD) refers to incidents where an unusually large number of aquatic organisms die suddenly over a short period. This phenomenon, common in rivers, lakes, estuaries, and coastal waters, may arise from natural events or human–induced factors. MFD often leads to serious ecological disruption, economic losses in aquaculture and fisheries, and deterioration of water quality. Globally, water pollution is a widespread problem, with human activities—especially untreated waste discharge—being a leading cause. Because MFDs usually involve multiple interacting factors, identifying the exact cause is complex. Many countries have established technical frameworks for investigating these incidents, including manuals and procedures guiding field inspection, sampling, and data analysis, with systems in Australia and South Africa considered highly comprehensive. In Vietnam, MFD cases have been recorded in five provinces, including Phu Tho, Hai Duong, Thai Binh, Thanh Hoa, and Dong Nai. Although local authorities have applied certain procedures, inconsistencies persist due to the absence of national standards. To address this, technical guidelines for determining MFD causes and assessing economic losses have been developed based on scientific evidence and Vietnam’s practical conditions. These guidelines aim to support the government in improving evaluation capacity, ensuring fair compensation, and promoting sustainable environmental management.