DHAKA, Bangladesh — Mohammad Monir, a fish seller from Khilgaon in Bangladesh’s capital Dhaka, was preparing a new batch of dad fish (Ompok pabda) in its tray. Due to the high demand for this fish, his first batch sold out quickly. Every evening, he manages to sell nearly 20 kilos of pabda.

“Pabda fish is delicious and costs comparatively less than other mouth-watering fish, between $2.5 (300 taka) and $4.18 (500 taka) per kilogram, depending on quality and supply,” said Monir. “We have two other outlets adjacent to this one. In total, we sell around 60 kg (132 lb) of pabda every day.

Another seller named Mohammad Shahin was selling the fish at $2.1 (Taka 250) per kg. Several customers were queuing in front of his store because he offered a cheaper price. “I sell on average more than 15 kg per day,” Shahin said.

Other vendors at the evening fish market shared similar experiences. As pabda fish is produced in abundance in the country’s aquaculture sector, its prices remain relatively affordable, in line with the growing demand.

Food prices soar in Bangladesh, with food inflation exceeding 10% for some time now. He even reached 14.1% in July. As a result, any fish that remains affordable to the middle class is in high demand.

However, a recent study published in ScienceDirect revealed high rates of antibiotic resistance in pabda fish. The study found particularly high frequencies of resistance to antibiotics such as trimethoprim (95%), sulfafurazole (75%), ampicillin (60%), amoxicillin-clavulanic acid (55%) and cephradine (50%) in pabda fish.

The study also found that the overuse of antibiotics in Bangladesh’s aquaculture system is spreading antibiotic resistance genes into the environment, posing significant health risks to consumers by exposing the food chain to multi-resistant bacteria ( LOL).

Afrina Haque, a faculty member at Jahangirnagar University’s zoology department, who led the study, told Mongabay that their research confirms the unnecessary use of antibiotics by Bangladeshi aquaculturists. The team collected samples of pabda fish from aquaculture systems due to the high market demand for this fish.

Pabda aquaculture covers about 1,500 hectares (3,700 acres), with an annual production of about 20,000 tonnes, according to Moshiur Rahman, senior scientific officer at the Bangladesh Fisheries Research Institute (BFRI).

Pabda fish is also caught in natural water bodies of Bangladesh including rivers, haors (large wetlands) and beels (smaller lakes), with approximately 1,000 metric tons collected from these sources.

“The demand for pabda is very high in the market due to its taste, desired fat content and absence of intermuscular bones. Farmers are interested in breeding this fish due to its high market demand and higher profits. Besides, the cultivation period of pabda is much shorter than that of carp or pangas,” Rahman told Mongabay.

To analyze the bacterial community in pabda aquaculture media and examine how bacteria persist in the culture environment, researchers isolated bacteria from the gills and intestines of fish. They also collected water and sediment samples from the pond.

“To understand the diversity of bacterial types, we selected 20 colonies for sequencing and performed molecular identification to identify the specific bacteria present in the samples. We then sought to find out whether these bacteria were pathogenic or beneficial. Most of the bacteria have been identified as pathogenic, some of which have already been found in poultry,” Haque said.

Unregulated antibiotic doses and health risks

Molecular identification revealed that many of these bacteria were resistant to antibiotics, with some exhibiting widespread drug resistance.

“We wanted to study how multidrug-resistant bacteria support biofilm production. Some studies indicate that certain bacteria promote biofilm formation, while others do not. In our research, we found that the bacteria did not produce pathogenic biofilms, which proves that our farmers are using antibiotics unnecessarily,” said Haque.

The researchers also noted that different fertilizers used in surrounding croplands are transported by rain and runoff to the ponds where the fish are raised.

In addition, Haque said, farmers often use antibacterial drugs to stimulate fish growth, mixing antibiotics into fish feed to prevent disease. However, what they may not realize is that this practice contributes to making fish resistant to antibiotics.

“As consumers, when we eat fish containing antibiotic-resistant bacteria, we can develop the same resistance. In some countries, people eat raw fish, increasing the risk of directly ingesting these harmful bacteria. And our fish is also exported,” said Haque.

“Our aquaculturists must therefore be warned that antibiotics should not be used indiscriminately. They should consult fisheries experts to determine the correct dosage and avoid overdoing it,” she added.

The growing impact of aquaculture in Bangladesh

Bangladeshis are known for their traditional fish-based diet. Against a total fish demand of 4.2 million tonnes, the country produces 4.7 million tonnes of fish. And aquaculture plays a crucial role in the overall fish production of Bangladesh.

Of this total, 1.3 million tonnes are caught in open water, around 7 tonnes come from marine fishing, and the remaining 2.7 million tonnes are produced by aquaculture. Bangladesh also exports 74,042 tonnes of fish, which accounts for about 1.05% of its export earnings.

Rahman said that farmed fish contribute 58% to Bangladesh’s total fish production, while open water fish account for 28%.

The contribution of Pabda to the country’s total fish demand remains modest, around 0.5%. However, Rahman noted that since the development of the first breeding technique in 2002 and the start of its cultivation in 2011-12, pabda cultivation has shown steady growth, especially from 2014-15.

“Earlier, pabda cultivation was limited to the Mymensingh region, but it is now spreading across the country and continues to grow steadily,” Rahman said.

Hygiene issue in aquaculture

Researchers and experts emphasize that fish farmers in Bangladesh need proper hygiene guidance to produce fish free of antibiotic resistance.

Haque said they found some diarrhea-related bacteria, which could potentially have entered the pond through human or animal feces. “This shows the importance of educating farmers on proper waste management, hygiene and pond maintenance,” she said.

“Additionally, fertilization practices in neighboring fields must be managed to avoid contamination of pond water. When fields are adjacent to aquaculture ponds, careful application of fertilizers and pesticides is crucial to avoid contamination through runoff,” she added.

Rahman also highlighted the growing concern over antibiotic resistance in Bangladesh’s aquaculture sector, “especially to veterinary antibiotics, without consulting specialists.”

“As a result, consumption of this fish may contribute to antibiotic resistance in the human body. We should take immediate steps to control the use of antibiotics in aquaculture farms, and relevant fisheries officers should be involved in any antibiotic treatment in these farms,” he added.

Banner image: Fishermen catch fish in a net in their aquaculture enclosure. Image from WorldFish via Flickr (CC BY-NC-ND 2.0).

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Quote:

Haque, A., Chowdhury, A., Bhuiyan, MNI, Bhowmik, B., Afrin, S., Sarkar, R. and Haque, MM (2024). Molecular characterization, antibiotic resistance profile and biofilm formation potential of the bacterial community associated with Ompok pabda fish farming in southwest Bangladesh. Microbial pathogenesis194, 106818 doi:10.1016/j.micpath.2024.106818