The natural conditions are favorable for aquaculture

Scientists say expanded Hanoi has 30,840 hectares of surface water usable for aquaculture with 17,945 farming households, 23 cooperatives and 17 aquatic breeder facilities. 

In 2016, the city put 21,131 hectares of surface water into aquaculture and got output of 110,000 tons, which can satisfy 40 percent of the local demand. 

However, many problems have arisen from cultivation, including environmental degradation.

The Hanoi Fisheries Sub-department recently analyzed the quality of fish from 300 samples it took from 10 concentrated aquaculture areas. 

Scientists did not find antibiotic residue or residue of Dipterex and Malachite green residue in the samples. 

However, the lead residue in three samples was found exceeding the permitted level. The samples were from Tri Trung of Phu Xuyen district and Lien Chau of Thanh Oai district.

The sub-department also took 200 fish breeder samples from 10 breeder production facilities and 1,800 commercial fish samples from 18 breeding concentrated areas for monitoring. 

No pathogen was found at breeder production facilities, but 306/1800 commercial specimens were contaminated with Aeromonas bacteria (17 percent), 283/1800 samples with Pseudomonas bacteria (15.7 percent); 279/1800 Streptococcus (15.5 percent); and 223/1800 samples were found infected with fungi (12.3 percent).

The analysis showed that though no epidemic had caused mass fish deaths, there were germs in farming ponds, which meant the threat was high. Scientists discovered a new kind of disease on Tilapia caused by TiLV virus.

More seriously, scientists warned that the water quality was declining.

The Hanoi Fisheries Sub-department examined 112 water samples from seven breeding facilities and found the BOD, COD, H2S and NH3 concentration exceeding the permitted levels in many samples. 

The agency released warnings to every commune as the analysis results showed serious organic pollution in water sources and introduced measures to deal with the problem promptly.

Epidemics and water pollution not only would lead to reduction in aquaculture productivity and affect food safety, but would also damage the entire ecosystem in lakes and rivers, thus making it no longer possible to breed fish.

However, the warnings have been ignored. Farmers do not have the habit of dredging mud in their ponds and treating the farming ponds with chemicals and bioproducts. 

In some aquaculture areas, the pollution has become so serious that farmers have to block inlets and outlets to prevent polluted water.

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Mai Chi