Why fish catch declines in the Bay
Marine scientists have warned that escalating pollution is crippling fish reproduction
The country's commercial fish catches in the Bay of Bengal have fallen sharply over the past three years and researchers have attributed the sharp decline in fish harvest to a combination of plastic, metal, chemical and oil pollution, uncontrolled overfishing, and indiscriminate trawling in shallow breeding zones.
They also point to environmental degradation in rivers that feed nutrients into the Bay of Bengal.
Bangladesh's 119 rivers supply nutrients that sustain marine food chains, but widespread siltation of estuaries has blocked this flow, reducing the nutrient input into the sea. As a result, fish stocks have declined even in deeper waters.
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Although Bangladesh has sovereign rights over 118,813 square kilometres of sea, commercial trawlers currently operate in only 27,000 square kilometres. Repeated fishing in the same areas has further depleted stocks of commercially valuable species, while limited investment and poor infrastructure have prevented expansion into deeper waters.
Marine scientists have warned that escalating pollution is crippling fish reproduction. A recent study found that microplastic concentrations in the Bay of Bengal are almost double those in the South China Sea.
"The Bay has one of the highest microplastic pollution levels in Asia. We also detected non-biodegradable PFAS chemicals and persistent organic pollutants (POPs) from pesticide runoff. These disrupt reproduction and reduce food sources," Majharul Islam, researcher and instructor at the Bangladesh Marine Fisheries Academy, told TBS.
The Marine Fisheries Department has 266 licensed commercial trawlers, of which around 232 are active, joined by nearly 66,000 smaller mechanised and non-mechanised boats.
Despite a legal ban on fishing in waters shallower than 40 metres, trawlers frequently violate the rule, using sonar to locate shoals and deploying illegal fine-mesh nets that trap juvenile fish. Bangladesh has also never conducted a Maximum Sustainable Yield (MSY) survey, leaving policymakers without reliable data on safe catch limits.
Unreported fishing is another problem. Vessel owners often under-report catches to the department, leaving the true harvest unknown.
Enam Chowdhury, president of the Bangladesh Marine Fisheries Association, said, "Commercial trawlers account for only 12% of total marine catch. The other 88% comes from over 70,000 small boats, most of which fish in shallow waters using illegal nets. They overexploit the resource, often without reporting catches. At this pace, Bangladesh's marine fishery will collapse."
He urged the government to enforce stricter monitoring and stop illegal fishing. "Otherwise, we will destroy our marine wealth in no time," he warned.
