Water Quality Blamed for Mass Fish Deaths on Vietnam's Hieu River

Authorities in Vietnam's Quang Tri province have determined that a mass fish kill in the Hieu River was caused by deteriorating water quality, ruling out disease as the culprit. The investigation involved collecting samples of both dead fish and river water.

Testing of 12 water samples from 10 locations and four samples of dead fish, including farmed and wild species, revealed no signs of common fish diseases like nervous necrosis or TiLV. However, water quality monitoring showed a significant increase in nutrient and organic matter levels compared to previous years. Several water samples indicated nitrogen levels at 'C' or 'D' grades (poor to very poor), with phosphorus levels also frequently falling into these categories.

Officials from the Department of Agriculture and Rural Development stated that these parameters reflect a clear decline in water quality, creating an unfavorable environment for aquatic life. This unusual change is believed to have compromised the health and resilience of both farmed and wild fish populations.

In response, the Department of Agriculture and Rural Development has recommended that the Provincial People's Committee direct the police to investigate the exact causes of the negative impact on the water source. The Department of Fisheries and Marine Guard has also issued urgent notices advising local residents to halt the use of water from the Hieu and Thach Han rivers for fish farming operations.

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The mass death of fish is due to abnormal problems with water quality, not disease.