Determine the cause of the mass death of nearly 1,000 tons of caged fish in Hai Duong

On April 12, Ms. Pham Thi Dao – Deputy Director of the Department of Agriculture and Rural Development of Hai Duong province said that the unit had just completed preliminary statistics on the phenomenon of mass deaths of caged fish occurring in 3 river systems: Thai Binh and Hai Duong. Kinh Thay and Luoc River in the area.

Accordingly, at the end of March, people raising fish in cages on the Thai Binh River, passing through Tien Tien ward (Hai Duong city), discovered scattered dead fish, lethargic fish, and suffocated fish floating to the water surface. After that, this situation continuously appeared in Nam Dong ward (Hai Duong city), communes in Chi Linh city, and districts: Nam Sach, Tu Ky, Thanh Ha.

From March 30 to April 8, caged fish died en masse in Tien Tien commune, Nam Dong ward (Hai Duong city) and many died in communes of 8 districts: Thanh Ha, Nam Sach, Tu Ky, Chi Linh, Ninh Giang, Kinh Mon, Cam Giang, Kim Thanh. By April 9, the number of dead fish showed signs of a sharp decrease.

According to statistics, the total amount of dead fish in districts/towns/cities is estimated at more than 954 tons. Results of a quick test of water samples at dead fish cage farming sites on three river systems showed that the dissolved oxygen content in the water was low or very low. Meanwhile, the toxic gas content (NH4, NO2) is very high compared to standards.

Analyzing results of water and fish samples from the Environmental Monitoring Center (Department of Natural Resources and Environment) and Aquaculture Research Institute I (Ministry of Agriculture and Rural Development) show that the toxic gas (NO2) content at all points is 3 times higher. time; Lead (Pb) content in Tien Tien commune is 1.67 times higher; Mercury (Hg) in Dai Son commune (Tu Ky) and Thanh Hai commune (Thanh Ha) is 3.5-5.7 times higher than the allowable limit.

Results of clinical examination and necropsy of fish samples did not observe symptoms or lesions of infectious diseases in fish.

Youth union members and people help farmers pick up fish and destroy them.

Environmental workers scoop up dead fish floating in the river and spilling into a densely populated area in Hai Duong City.

Ms. Pham Thi Dao informed that specialized units determined that the cause of fish death was due to lack of oxygen, not due to disease factors. Professional units also recommend, guide, and support farmers to increase oxygen generation measures (aeration, water rotation, cage cleaning…) and enhance disease prevention for fish. At the same time, reduce the density of fish raised in cages, focus on collecting, processing and destroying dead fish, not spreading into the environment causing pollution and disease.

The Department also requested the Provincial People’s Committee and the Ministry of Agriculture and Rural Development to continue to direct specialized agencies to assist in determining the cause of lack of oxygen in the water; Strengthen monitoring and assessment of water quality in rivers, especially upstream areas for early warning.

Nguyen Hoan