Posted on March 30, 2026
Ilish, one of Bangladesh’s signature fish, is experiencing a decline in annual production due to erratic weather, overfishing, navigability constraints, and the growing impacts of climate change. To boost production, the Department of Fisheries (DoF) is considering a large-scale dredging initiative—estimated at around Tk9,000 crore—to restore disrupted migration routes.
Heavy sedimentation in key river estuaries continues to obstruct ilish’s natural breeding pathways. Fisheries department data show that production fell to a seven-year low in the 2023–24 season, with output standing at 5.29 lakh tonnes—around 42,000 tonnes less than the previous year.
In recent years, ilish yields had shown a steady upward trend: 5.71 lakh tonnes in 2022–23, 5.66 lakh tonnes in 2021–22, 5.65 lakh tonnes in 2020–21, 5.50 lakh tonnes in 2019–20, and 5.32 lakh tonnes in 2018–19—though the growth margins remained narrow.
According to officials, the Ministry of Fisheries and Livestock has written to the ministries of shipping and water resources, proposing dredging of around 20,000 kilometres in the Meghna and Tetulia river estuaries.
Experts say mature ilish migrate upstream from the sea into rivers during the spawning season and return to the sea after laying eggs. However, this migration route—from sea to river and back—is becoming increasingly silted up, leading to the formation of submerged sandbars.
As a result, ilish can no longer move upstream freely, disrupting their breeding cycle. Sources say at least 25 chars or sandbars that have emerged within river channels are now obstructing the species’ life cycle.
It is estimated that the Meghna–Tetulia estuary in Chandpur alone has accumulated around 88 crore tons of sediment in these char areas.
Although the natural river depth should be between 5 and 10 metres (15 to 30 feet) to support ilish movement, sedimentation has reduced depths to just 2 to 3 metres in some areas.
Molla Emdadullah, project director of the Department of Fisheries’ ilish Resource Development and Management Project, told Dhaka Tribune on Friday: “ilish require a minimum water depth of 5 to 10 metres for migration. However, due to siltation along estuary routes, the depth has dropped to just 2 to 3 metres in some areas.
“We have written to the two ministries at different times, requesting dredging of these routes. They informed us that billions of cubic metres of sediment have accumulated in just a 50-kilometre stretch of the Meghna estuary. Removing this through dredging would require about Tk1 lakh crore. However, in our current proposal, we have suggested dredging a waterway that is 2 kilometres wide and 20 kilometres long.”
When asked, he said the proposal had been sent last November during the interim government’s tenure, and the new government is keen to continue discussions.
Multi-billion taka dredging proposal
The proposal identifies four main ilish migration routes for dredging:
- 20km in the Meghna estuary (Bhola, Noakhali, Chittagong, Patuakhali)
- 10km in the Tetulia estuary (Patuakhali, Rangabali)
- 10km in the Andharmanik River (Patuakhali, Kolapara)
- 10km in the upper Meghna (Barishal, Chandpur, Laxmipur)
Experts estimate that dredging 20km of the Meghna estuary alone would cost about Tk4,760 crore and require the removal of around 47.6 crore tonnes of sediment, while the Tetulia section would need an additional Tk2,380 crore.
Experts caution that dredging without proper assessment could backfire.
Fisheries scientist Dr Md Anisur Rahman said: “Dredging must consider both benefits and risks. Otherwise, it may worsen the situation. When ilish encounter obstacles, they often turn back to the sea instead of moving upstream.”
He noted that about 35% of Bangladesh’s ilish production comes from Bhola, making these routes critically important.
River experts also warn that without continuous maintenance dredging, any benefits will be short-lived.
