Van Ninh: Lobsters die in large numbers for unknown reasons

For about a month now, a lot of lobsters in Van Ninh district have died, but the cause is still unknown. Authorities are investigating and coming up with solutions to advise people to overcome this situation.

Mass shrimp deaths

Mr. Nguyen Van Tien (Ha Gia village, Van Hung commune) has a shrimp raft with 35 cages, shrimp can be raised for about 5 - 6 months, size from 150 to 200g/shrimp. According to Mr. Tien, every day, his family's shrimp raft dies about 20 - 30 shrimp, causing great damage. His family has to urgently sell suffocated shrimp at half price (about 350 - 600,000 VND/kg depending on the type) to traders.

The farming area in Van Hung commune has about 4,200 cages (211 farming households). The main farming object is green lobster. The stocking density is about 200 - 300 lobsters/cage. Lobsters raised in this area have been raised for 5 months, with sizes ranging from 150 to 200g/lobster. According to records from farming households in the area, the phenomenon of large lobster deaths has occurred in the past 20 - 30 days, with 3 to 30 lobsters/household dying per day. In the farming area, more than 50% of farming households have seen shrimp deaths with signs of pink-white abdomen, reduced or no appetite, less active, sluggish, gradually weakening and dying. Farmers said that the water temperature in the farming area this year is hotter than the same period in 2023. Based on the signs on the shrimp, farmers suspect that the lobsters died of milk disease.

The phenomenon of mass lobster deaths also occurred in Van Thanh commune. The farming area where the dead lobsters were discovered was in Mui Nui Nai area, Khai Luong village. According to records from farming households, the phenomenon of lobster deaths has occurred for about 30 days recently and only occurred in spiny lobsters, not in green lobsters. Mr. Phan Ngoc Nam said that his family has 40 cages for commercial lobster farming for about 5 months, about 10% of them died. When he saw signs of lobster death, he used antibiotics to treat it many times but it did not improve.

According to Mr. Vo Van Thai - Director of Van Phong Aquaculture and Tourism Cooperative, currently, the situation of lobsters weighing about 0.2 - 0.25 kg/lobster with black gills has caused about 40% of them to die. There are still 6 months left before they can be sold, but the situation of dead lobsters is still happening, and farmers are at risk of heavy losses.

People sell suffocated shrimp to traders at cheap prices.

Survey to find the cause

According to the provincial Department of Animal Husbandry and Veterinary Medicine, in the Van Thanh and Van Hung farming areas, the results of measuring environmental indicators in the area where the lobsters died showed that all environmental factors were within the allowable limits. Test results did not detect parasites or pathogens causing milk disease in shrimp, but found that the shrimp were infected with bacteria. Based on the results of the investigation of epidemiological information in the farming area, the cause of death in the shrimp could not be clearly determined.

Mr. Nguyen Ngoc Y - Head of the Economic and Infrastructure Department of Van Ninh district said that every year, at the time of changing seasons, shrimp often die. After being checked, the environmental indicators are all within the allowable range. However, the hot temperature and lack of oxygen in shrimp can also be one of the factors causing shrimp to suffocate and die. On April 16, the district will coordinate with the Department of Agriculture and Rural Development and the Aquaculture Research Institute III to survey two farming areas in Van Hung and Van Thanh communes to find the cause and have specific solutions to solve this problem.

The provincial Department of Animal Husbandry and Veterinary Medicine recommends that aquaculture farmers regularly measure environmental factors during the changing weather seasons, especially oxygen, to promptly detect changes in environmental factors and have solutions; closely monitor weather fluctuations, changes in water color, shrimp health; remove dead shrimp, molted shrimp and shrimp that settle to the bottom. In addition, add vitamins and minerals to the diet to improve the resistance of lobsters; avoid excess food causing waste deposition, creating conditions for pathogenic microorganisms to develop...

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