
The cause, according to villagers and environmentalists, is the illegal use of battery-powered electric shock machines to catch fish during the night.
The practice, carried out in darkness across different parts of the haor, has triggered fresh concerns about the future of one of Bangladesh’s most important freshwater ecosystems.
Tanguar Haor, located in the Sunamganj district’s Madhyanagar and Tahirpur upazilas, is an internationally recognised Ramsar site and among the country’s largest wetlands.
It supports rich biodiversity, sustains thousands of fishing-dependent families and attracts migratory birds, as well as domestic and foreign tourists, every year.
But environmental experts warn that the indiscriminate use of electric shocks for fishing could cause long-term and possibly irreversible damage.
“Electric fishing does not discriminate,” said local resident Nazier Hossain, adding, “Large fish die, but so do fingerlings, small fish and other aquatic animals. This destroys the natural breeding cycle and severely harms the haor’s ecosystem.”
Residents say organised groups operate at night, moving from one area of the wetland to another with shock machines powered by batteries.
Fish killed instantly by electric current are collected, while many others are left to float to the surface by morning.
The practice has alarmed conservationists, who say it threatens not only fish stocks but the entire ecological balance of the wetland.
Tanguar Haor plays a crucial role as a breeding ground for freshwater species and as a habitat for countless aquatic organisms that form the base of the food chain.
If this continues, the biodiversity of the haor will face extreme danger, environmental experts warn, adding that a major fisheries crisis could emerge in the future.
The issue has also raised questions about enforcement in the protected wetland area. Members of the local community have demanded stronger action, including increased night patrols, mobile courts and the seizure of illegal shock machines.
Without swift intervention, they say, the destruction could accelerate during peak fishing seasons, reports UNB.
Madhyanagar Upazila Nirbahi Officer (UNO) Ujjwal Roy acknowledged the seriousness of the allegations.
He said the use of shock machines for fishing in Tanguar Haor is completely illegal and constitutes a punishable offence.
“The administration is taking a strict stance to protect the haor’s environment and fisheries resources. If complaints are received, immediate operations will be carried out and legal action will be taken against those involved,” he said.