80 tonnes of farmed snails die en masse in central Vietnam

The mass deaths affected 13 households farming nearly eight hectares in Dai Lanh Commune, according to the local authorities.

Water samples taken from several farming areas showed ammonium concentrations above permitted levels, indicating organic pollution caused by accumulated leftover feed, animal waste, decaying algae, and dead microorganisms.

Dai Lanh has about 44.5 hectares of spotted babylon snail farms, mostly using earthen ponds, with many farmers having stocked juvenile snails since March.

They have hired workers to clear large quantities of dead spotted babylon snails from their ponds.

Nguyen Son, 58, who farms more than one hectare, said his snails had been raised for nearly five months and were close to harvest, at about 200 per kilogram, when they suddenly died within days.

Son said he had invested more than VND1.4 billion (about US$54,000) in the crop and was now facing a total loss.

“After months of hard work, we have lost everything,” he said.

Local authorities said prolonged southerly winds and harsh weather had also caused fluctuations in the farming environment, increasing mortality among aquatic species.

Farmers have been advised to treat and closely monitor water quality, maintain aeration, remove dead snails, and reduce feeding when ammonium levels rise.

Authorities also recommended using biological treatments or zeolite-based absorbents to help reduce toxic compounds in farming ponds.