A recent survey by the Department of Fisheries (DoF) has uncovered alarming levels of siltation in 52 critical locations across major rivers vital to hilsa migration, severely disrupting the fish’s natural breeding cycle and contributing to a sharp decline in production.
The findings, part of an urgent assessment submitted to the Ministry of Fisheries and Livestock, highlight a 50-kilometre stretch of severe sedimentation along the Meghna and Tetulia rivers – from Sonarchar in Rangabali of Patuakhali, to Dalchar in Noakhali. This zone is a key migratory corridor for hilsa traveling from the Bay of Bengal to freshwater spawning grounds.
According to the DoF, the silt buildup has significantly reduced water depth and flow, blocking hilsa’s upstream movement during the critical breeding season.
In several areas, riverbeds have risen by up to 1.5 meters, rendering traditional migration routes impassable.
“This siltation is not natural. It’s accelerated by deforestation, unplanned infrastructure, and riverbank erosion,” said a senior DoF official involved in the survey. “We’ve identified 52 hotspots where immediate dredging is essential to restore navigability and ecological balance.”
The survey also found that silted zones coincide with historically high hilsa catch areas, now reporting dwindling returns. Local fishers in Patuakhali and Noakhali confirmed that hilsa are no longer reaching upstream regions in previous numbers.
While the government has long focused on riverine conservation, such as seasonal fishing bans and jatka (juvenile hilsa) protection, the new data underscores a critical gap: no coordinated effort exists to address physical barriers like siltation.
Adding to the crisis, the survey notes that illegal fishing structures, particularly permanent "Tong" and "Gop" nets are being installed in and around these silted zones, further obstructing fish movement and enabling mass capture of adult and juvenile hilsa alike.
Molla Imdadulla, Project Director of the Hilsa Development and Management Project, acknowledged the findings: “Our conservation programs are river-based, but if the rivers themselves are choked, those efforts are undermined. Clearing silted routes must now be a top priority.”
The DoF has recommended immediate dredging operations, realignment of river channels where necessary, and enhanced monitoring to prevent illegal construction in ecologically sensitive zones. It has also called for inter-agency coordination with the Bangladesh Water Development Board and local authorities.
Environmental experts warn that without swift action, the siltation crisis could permanently alter hilsa migration patterns. “You can ban nets and offer incentives, but if the fish can’t physically reach their breeding grounds, the population will collapse,” said Dr Fakhrul Islam, a freshwater ecologist.
With hilsa prices now exceeding Tk 3,000 per kg in wholesale markets and vanishing from many retail outlets, the DoF’s findings spotlight a growing ecological emergency—one that threatens not only a national fish but the livelihoods of hundreds of thousands dependent on the hilsa economy.
Source: BSS