Ben Tre (VNS/VNA) - Many farmers raising giant river prawns in the Mekong Delta province of Ben Tre are facing losses due to saltwater intrusion, which is decimating the crustaceans.

Le Thi Diep, who rotates between rice and giant river prawns in a 1.6ha field in Thanh Phu district’s My An commune, had more than 130,000 prawns in this year’s crop. After four months they had grown to the size of a human thumb. But hot weather and the high salinity rate have been killing many for over more than half a month now.

More than 70 percent are now dead, and they are continuing to die, and she is certain to suffer losses, she said.

Saltwater intrusion has caused the salinity rate to consistently reach 2 percent this year and even 2.4 – 2.5 percent on some days, a condition in which giant river prawns cannot survive, according to farmers.

Le Thi Suong is breeding the creatures in her 4ha farm in My An, and has also seen thousands of prawns die every day from the salinity.

In the past the salinity rate would never exceed 1.7 percent, and giant river prawns could withstand it, she said.

“This year the salinity rate has exceeded 2 percent, and if the situation continues, all my prawns will die.”

Vo Van Hien, head of the Thanh Phu Bureau of Agriculture and Rural Development, said provincial authorities are telling farmers how to mitigate the impacts of saltwater intrusion.

The delta is facing severe intrusion this dry season, and Ben Tre is one of its coastal provinces, which have been hardest hit.

Nearly a third of the province’s 3,000ha of giant river prawn farms has been affected by saltwater intrusion with a death rate of 30 percent, according to the provincial Department of Agriculture and Rural Development.

The worst affected areas are in Thanh Phu, Giong Trom and Mo Cay Nam districts.

The giant river prawn is farmed in 3.2 percent of the province’s total aquaculture area, but it is one of the province’s key fisheries products because of its high value and Ben Tre’s potential for breeding it, according to the department.

Local farmers breed giant river prawns in ponds and irrigation ditches in orchards and also rotate it with rice in paddies.

The breeding of giant river prawns in ditches in orchards, especially coconut groves, has become common in the province in recent years since it offers a steady income.

The province is the country’s largest coconut producer and has around 72,000ha of trees.

Of the figure, irrigation ditches make up 10,800ha, or 15 percent, according to the province’s Agriculture Extension Centre./.