Lobsters have died en masse in the southern central province of Khanh Hoa due to prolonged hot weather. Photo by Tienphong.

Initial investigations from the ministry showed that the recent mass deaths of lobsters were caused by the hot weather, high density and low oxygen levels which have badly affected their health.

The ministry has asked concerned departments to instruct farmers to deal with the problems to limit losses and prevent environmental pollution in the area.

"Lobsters are being raised in high density with an average level of over 17 lobsters on a square metre in Van Ninh," the ministry said. "Farmers should be instructed to reduce the density level during hot weather between April and June and keep their water environment clean to ensure lobsters' good development."

Some 200 households in Van Ninh District have reported mass lobster deaths over the past week.

Nguyen Van Tai said that he and other farmers have lost 30 percent of lobsters aged between 3-6 months in their cages.