On the afternoon of 31/5, Phu Trach Communal Police announced they are coordinating with the Quang Tri Provincial Police Criminal Investigation Department to investigate the cause of a mass shrimp death incident at Doan Manh Thanh’s aquaculture pond in Dong Hung hamlet.

Shrimp floating on the pond surface. Photo: Minh Anh

The incident began on the evening of 28/5 when a worker checking Thanh’s whiteleg shrimp pond discovered numerous dead shrimp floating on the water. Arriving at the scene, the pond owner observed widespread shrimp mortality.

By the following morning, the entire stock of 50,000 shrimp, which had been cultivated for 45 days, had died and gathered in the pond’s corners. The shrimp had reached a size of approximately 150 shrimp/kg. Upon inspecting the water, Thanh noticed an unusual odor, leading him to suspect sabotage and report the incident to the police.

During the scene investigation, authorities collected water samples for analysis. On 29/5, while draining the pond to collect the dead shrimp, Thanh discovered eight bags of calcium carbide, tightly wrapped in plastic, at the bottom of the pond. He then handed them over to the police.

After the shrimp died, Thanh drained the water and found eight bags of calcium carbide at the pond’s bottom. Photo: Minh Anh

According to Thanh, the estimated damage is around 700 million dong. All dead shrimp have been collected and buried for disposal. "This shrimp pond usually takes about three months to harvest, and we were only halfway there. If this hadn't happened, the revenue could have exceeded 2 billion dong, but now everything is lost", he stated.

Thanh's family has been raising whiteleg shrimp for six years. This is the first time such a widespread death has occurred. Previously, even during disease outbreaks, shrimp deaths were scattered. The pond owner stated that his family has no conflicts with anyone but suspects someone intentionally put calcium carbide into the pond.

The collected shrimp were disposed of by Thanh through burial. Photo: Minh Anh

Calcium carbide (CaC₂), commonly known as "dat den", is a chemical frequently used in industry. When it comes into contact with water, it reacts strongly, producing acetylene gas and altering the water environment. In large quantities in aquaculture ponds, calcium carbide can cause environmental shock, oxygen depletion, and mass deaths among shrimp and fish.

Dac Thanh