ĐÀ NẴNG — Authorities are investigating the mass fish deaths on floating farms in a section of the Cổ Cò River in Đà Nẵng’s Ngũ Hành Sơn District, officials said on Monday.

Around 60 tonnes of fish were found dead in the area on Monday.

District Deputy Chairman Huỳnh Cự said the fish were found dead in 65 out of total of 228 cages maintained by 32 floating farms on the Cổ Cò River.

The district and relevant agencies have mobilised trucks to remove and bury the dead fish, he said.

Tests will be carried out and results released soon, Cự said.

Breeding fish has been as a major breadwinner for 30 households living in the disrict’s Khuê Mỹ Ward.

The Cổ Cò River runs through the Hòa Cầm Industrial Park in Hòa Vang District before reaching the fish farms in Khuê Mỹ.

In another incident of mass fish deaths in the city’s 29-3 Lake last year, poor levels of dissolved oxygen (DO) in the water and pollutants released from the city’s drainage system were blamed. The 29-3 Lake is biggest in Đà Nẵng.

In different researches and surveys in previous years, experts have warned that almost all lakes in the city are contaminated with toxic metals and other dangerous substances contained in wastewater.

The city has invested VNĐ15 billion (over US$700,000) in wastewater treatment, but that is still a modest amount compared to what is needed.

Reducing fish cages in Bà Rịa – Vũng Tàu

Meanwhile in Bà Rịa–Vũng Tàu Province, authorities have decided to reduce half of the fish cages in Chà Và River in order to reduce pollution and fish deaths.

According to the People’s Committee of Vũng Tàu City, 260 families and 11 enterprises raise fish in about 8,000 cages. The committee said the density of the fish farming prevents water flows among the cages, causing environmental pollution. For example, in Area 4, there are 1,852 cages, more than double the planned number. Massive fish deaths resulting from the crowded conditions have caused economic damage.

Nguyễn Dũng, a farmer with 10 years of experience raising fish in Chà Và River, said reducing the density would help fishes develop and reduce the threat of pollution-caused fish death.

The establishment of self-management groups to manage and support cage owners will follow as the next step of aquaculture stabilisation, said Lê Xuân Tú, Long Sơn Commune’s Secretary. — VNS