A number of fish raised in floating cages in along the Buoi River in the north-central province of Thanh Hoa have died as the river was contaminated with untreated water dumped by a local sugar plant, authorities said Saturday.

The mass deaths hit fish farms in as many as 15 communes in Thach Thanh and Lac Son districts, whereas wild fish and shrimp in the river also died en masse, according to a report submitted to the provincial administration.

Seventeen metric tons of fish, raised in 71 floating fish cages of 32 households in Thach Thanh District. In the district’s Thanh Vinh Commune alone, there were ten metric tons of dead fish found from 28 affected farms.

Farmers had no choice but to destroy the dead fish when harvest time is near.

Le Van Ve, who runs two floating fish cages on Buoi River, was about to harvest more than 300 fish, weighing from 2.4 kg to 3 kg, for sale when they all died.

“At the current market price of VND100,000 [US$4.46] a kg, I incurred a VND70 million [$3,125] loss in only two days,” the 54-year-old farmer said in tears.

“My only hope now is the government will support us to make up for the loss.”

Local fish farmers said the aquatic creatures started dying en masse on Wednesday, from the section of the Buoi River that passes through the Bien village in Thach Lam Commune, Thanh Thanh District.

Local authorities have checked the wastewater discharge system of plants along the river to look for the cause of the fish deaths.

They later found that the Hoa Binh sugar plant had dumped untreated water directly into the river.

The facility admitted on Saturday that they had discharged some 300 cubic meters of wastewater into Buoi River on an annual basis.