Thousands of shrimp farmers in five upazilas of Bagerhat are counting heavy losses as shrimps are dying in numbers due to high water temperatures and salinity in shrimp enclosures.

Receding water level due to poor rainfall this rainy season is the primary reason behind the rise in temperature and salinity in the enclosures in Mongla, Rampal, Kachua, Chitalmari, Morrelganj and Sadar upazilas, the farmers speculated.

Carp fish farmers in the region said they are also facing the same problem.

Shrimp farmers in the affected upazilas may not reach their production target this year if the situation does not improve soon, said officials at fisheries department in Bagerhat.

Babul Sheikh, a shrimp enclosure owner in Kalmibuniya village under Badhal union of Kachua upazila, said he spent Tk 4 lakh on shrimp larvae for his enclosure on 12 bighas of land.

His investment is at risk now as a large number of shrimps are dying in his enclosure where level of water is falling and its temperature and salinity are rising.

Water temperatures in surrounding canals and waterbodies - also suffering from shortage of water - also rose significantly, resulting in the deaths of carp fish, he said, adding that drawing in the hot water from those sources into the shrimp enclosures does not

improve the situation.

Shrimp farmer Balaram from Kurmani village in Chitalmari upazila said it cost him Tk 2 lakh to release over 20,000 shrimp larvae and carp fish in his enclosure. But many of the shrimps and fish are dying as water in the drying enclosure has heated up.

Businessman Gopal Das from Sangdia village in Kachua upazila said near about 8 lakh shrimps have died due to high heat this season in his enclosure on 35 bighas of land.

Dr Khan Kamal Uddin Ahmed, chief scientific officer at Bagerhat Shrimp Research Centre, said the impact of climate change has started to become visible. "The temperature is the main reason behind the deaths of the shrimps. We even got 39 degrees Celsius temperature in a pond in Bagerhat this season."

He also said the shrimp farmers in the district now need to change their cultivation techniques, which has been flawed for long. The shrimp enclosures need to be deeper and there should be sheds above.

Bagerhat District Fisheries Officer (Acting) Amal Kanti Roy said tolerant temperature for shrimp is between 27 and 28 degrees Celsius and the level of water in enclosures need to be three to four feet high.

Water temperature in the enclosures is rising this season when the water level is falling to one to two feet, resulting in the deaths of shrimps, he added.