Data-driven Hilsa forecast steers Bengal fishermen to record catch
On August 11, fishermen returning to the Digha coast of West Bengal landed an unusually large haul of Hilsa fish, with estimates placing the day's catch at 30–40 tonnes. The bumper catch sparked excitement not only among local fishing communities but also among scientists at the Indian National Centre for Ocean Information Services (INCOIS) in Hyderabad, hundreds of kilometres away.
The record haul appeared to validate the effectiveness of INCOIS's species-specific Hilsa Fishery Advisory (HiFA), a forecasting system designed to help fishermen identify favourable fishing grounds for the prized fish. Launched last year during INCOIS's Foundation Day celebrations, HiFA was developed primarily to support fishermen along the West Bengal coast.
The advisory uses advanced machine learning algorithms to predict Hilsa availability at sea and categorises fishing prospects into five levels: very low, low, medium, high and very high. According to INCOIS Senior Scientist Sudheer Joseph, the system provides daily forecasts with a three-day outlook, enabling fishermen to quickly identify potential fishing zones.
Advisories issued on August 9, 10 and 11 had identified high to very-high-potential fishing zones near Digha, where oceanic conditions were favourable for Hilsa aggregation. These predictions are based on the interaction of several environmental factors, including sea surface temperature, salinity, ocean currents, and freshwater influence associated with rainfall and river discharge, explained Joseph.
Hilsa is among the most sought-after fish species in eastern India and commands premium prices in local markets. The fish is particularly sensitive to changes in coastal environmental conditions. During the monsoon, heavy rainfall and river discharge bring freshwater and nutrients into the Bay of Bengal, creating strong gradients in salinity and productivity. These river-sea interactions significantly influence Hilsa movement and aggregation as the fish migrate between marine and estuarine ecosystems. Ocean currents further shape these conditions, creating pathways where fish tend to concentrate near the coast and around estuarine mouths.
INCOIS Director T.M. Balakrishnan Nair said the Digha episode demonstrates the growing potential of data-driven fisheries advisories. The real achievement lies not merely in predicting a bumper catch but in identifying the environmental signals that precede fish aggregation and translating them into actionable information for fishing communities.
The HiFA system integrates satellite observations, numerical ocean models and fisheries science to provide practical guidance for fishers. Instead of spending time and fuel searching vast stretches of sea, they can focus on areas where conditions are predicted to be favourable. As another scientist, Alakes Samanta, noted: “In a changing ocean, where the distribution and timing of fish availability are becoming increasingly difficult to anticipate, the ability to read these signals may become as important as the catch itself.”
This development comes at a time when climate change is altering marine ecosystems, making traditional knowledge less reliable. By providing scientific, data-backed forecasts, HiFA offers a modern tool to help fishing communities adapt to these changes. While the system is still relatively new, the Digha success story suggests that tailored ocean information services can play a significant role in supporting sustainable fisheries and the livelihoods that depend on them.
