Shrimp mortality worries Southwestern farmers

Shrimp farmers of Khulna and Satkhira are at a loss as the shrimps in their enclosures are dying due to various reasons be-fore harvest season begins.

According to fisheries experts, lack of biosecurity, lack of enclosure depth, problems with water sources, lack of oxygen and shortage of food, along with excess heat is killing the shrimps.

Shrimp farming is one of the sources of income in the southern region. A huge number of people in Khulna, Satkhira and Bagerhat districts are dependent on shrimp farming.

The farmers are now stressed about facing a huge financial loss. Many are looking for alternative professions to get out of the incurred debt.

Talking to the shrimp farmers, this correspondent found that most of the shrimp fish in the district’s enclosure died at the beginning of production this year. The farmers were unable to save their shrimp even after following the advice of fisheries officials.

Many farmers have lost their capital and taken loans to save the rest of the shrimp by applying products as per the experts’ advice. Some of the fish in the enclosures are also dying alongside the shrimps.

Now the farmers are distressed as there is a rush to repay loans from banks and NGOs.

According to the farmers, the majority of the 35-45 days old shrimps tend to die more. This is a huge loss of investment as the shrimps are then at their prime time to be harvested. Once the marine lifeforms start dying in an enclosure, it spreads like an epidemic and takes several months to recover.

As far as the cultivation method is concerned, farmers release the fries at the end of the Bengali month of Magh (early Feb-ruary). Sometimes they delay the process by a few weeks if they cannot get enough water in the enclosures.

It takes about two to three months for the fries to mature enough to be harvested. Usually after two months, each Bagda shrimp weighs about 15-20 grams. And after three months it weighs 30-35 grams.

Currently, most of the farmers have started harvesting the shrimp at the two-month mark due to the fear of them dying.

About 2,000-3,000 fries are released per bigha of enclosure per month. Fish are harvested until the Bengali month of Agra-hayon in batches. Lime, manure, zeolite, auto polish and some other products are used in the enclosure to keep the shrimps and fish healthy. The depth of water in most enclosures is about 1.5-2 feet. They do not have any biosecurity and are usual-ly full of algae. Bagda shrimps are cultivated in this method in about 95 per cent of the enclosures in the area.

Tyebur Rahman, a shrimp farmer of Deyara village in Khulna’s Koyra upazila, said he cultivated shrimp on three bighas of land this year.

“About five weeks after I released the fries, the mature shrimps started dying. I was planning to start harvesting after eight weeks when they get large enough that 60-70 pieces make a kilogramme,” he said adding that he had incurred losses the same way last year.

Abdul Hai, a shrimp farmer from the same area cultivated Bagda shrimp on five bighas of land. His shrimp started dying af-ter about a month and 10 days.

“I released more fries and added lime and fodder in the enclosure. But the fries also started dying alongside the mature shrimp. I had to take a loan to feed my family and was forced to find other work,” he said.

Abu Daud of Asashuni upazila of Satkhira said most of the shrimps in their area are dying at the age of 35-45 days. “Many farmers started harvesting and selling a month-old shrimp to cover their production costs. Some enclosures did not suffer, but most did,” he added.

Bidyut Mandal, President of Bagerhat’s Mongla upazila Fishermen’s Association, said the death of mature Bagda shrimp has become an epidemic.

“This year, most of the shrimps released in the first phase died after becoming 1.5 inches in size. Once the shrimp death starts in one enclosure, neighbouring ones are also affected. And it takes about two to three months to improve the enclo-sure environment,” he said.

According to the Khulna District Fisheries Office, there are 20,430 Bagda shrimp farming enclosures in the district. The total area of which is 32,998 hectares. Satkhira district has 66,597 Bagda shrimp farming enclosures on a total area of about 78,240 hectares.

Senior Fisheries Officer of Koyra upazila, Aminur Haque said EMS (Early Mortality Syndrome) is appearing in some places recently. This results in the death of marine animals within six to seven weeks.

“It is caused by bacteria called Vibrio parahaemolyticus and Vibrio harveyi. Besides, the increase in temperature is also a cause,” he said.

In response to a question the officer told The Business Post, “To prevent EMS, nets should be used around the perimeter to ensure the biosecurity of the enclosure. Depth must be increased to maintain 3 to 5 feet of water at all times. Apart from releasing virus-free PCF larvae, a good aqua culture method should be adopted.”

Satkhira District Fisheries Officer Md Anisur Rahman said due to excessive heat, the water in the shallow enclosures gets evaporated and caused a lack of oxygen.

“Besides, the management of the enclosures is not suitable for shrimp farming. We continue to advise shrimp farmers on what to do,” he said.

In response to a question, Anisur said that they have not tested any samples to confirm whether or not the death is caused by any virus or bacteria.

Khulna District Fisheries Officer Jaydev Pal said, “Samples have been sent to the lab. The actual reason cannot be confirmed till the report is received.” He added that Bagda shrimps are dying due to environmental problems including excessive heat. In addition, it can also die of disease. Increasing the depth of the enclosures will help prevent these situations.”