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Warning about abnormally death of fish farming in Cai river

Nearly 1 month ago, fish raised in cages and rafts on Cai river in Hiep Hoa ward (Bien Hoa city) had a phenomenon of lethargy, not eating and floating on the water surface. This fish death phenomenon occurs regularly and tends to increase rapidly, causing great damage to farmers.
 

songCai.jpgPeople took dead fish from the raft on Cai

According to Mr. Tran Van Quyet, the owner of fish rafts on the Cai River, for over a month, fish raised in the raft has been lethargic, refusing to eat and floating on the surface of the water. Realizing this is the phenomenon of fish suffocating due to lack of oxygen, so the fish raisers in this area always keep the aeration system to provide oxygen 24/24 operation.

The alarming thing is that the dead fish in the Cai River area is increasing rapidly every day. Mr. Tran Van Trung, another fishing raft owner in this area, both picked up the dead fish and grieved: “Last month, the fish only died but now every few hours I have to pick up the dead fish once, every day the raft wastes hundreds of kilograms of fish of all kinds ". In order to reduce the damage, many rafters with large weight fish are taking advantage of selling fish. However, due to the slow consumption of the market, the traders only buy in moderation, making the farmers feel like sitting on a fire.

Faced with the reflection of fish rafters on the Cai River about the abnormal death of fish in cages, Sub-Department of Fisheries (Department of Agriculture and Rural Development) has repeatedly visited the raft farming area to survey and check. Results of environmental monitoring of fish farming area on Cai river in Hiep Hoa ward (Bien Hoa city) of Sub-Department of Fisheries in July showed that many parameters of culture environment are still within the permitted limits. Specifically, the observed parameters NO2, N-NH4 +, PO4 3-, COD, TSS, H2S were still within the permissible limit. Dissolved oxygen (DO) parameters are always low, ranging from 2.8 to 3.0 mg/l (sometimes down to 2.6 mg/l), not meeting the requirements for the purpose of placing aquaculture cages.

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People took dead fish from the raft on Cai river

Report received most recently is the water environment test results of the Fisheries Department in the morning of July 29, the dissolved oxygen content in surface water in the area of ​​the fish cage on the Cai River is much lower than the previous measured results. Specifically, the dissolved oxygen content in surface water in fish cages is only about 1.8 mg/l; Dissolved oxygen content in the riverbank area near the raft area was 2.5 mg/l and in the middle of the river was 3.2 mg/l, both 4 mg/l lower than the permitted QCVN. In particular, the oxygen content in the fish cage is about 2.5 times lower than the standard level. The measurement results of river water flow in the raft are only 0-0.1 (almost no movement) while outside the raft area is nearly 0.3. This is also the reason why the oxygen content in the raft area is lower than in other areas on the river.

Faced with abnormal fish death, Fisheries Department has sent a document to Bien Hoa City People's Committee proposing to implement many solutions such as: guiding people to anchor the raft at the right distance, ensuring clear flow to Increase water exchange capacity in rafts and cages. Advise farmers to increase aeration, water fan, oxygen to increase oxygen supply for fish, especially at the time of standing water. Actively reduce biomass, reduce fish density in cages compared with dry season. Increase sterilization, clean cages, clean and airy. In addition, farmers also have to proactively preserve environmental sanitation in the fish farming area by picking up dead fish, collecting domestic waste in the farming area ...

In addition, the People's Committee of Bien Hoa City and other responsible authorities are continuing to search for this unusual cause of death to avoid the risk of mass death of fish as before.

 Nam Vu

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