For generations, India’s fishermen have read the sea by instinct, relying on experience, weather patterns and knowledge passed down through families to find productive fishing grounds. Today, many head out guided by satellites orbiting hundreds of kilometres overhead. What began as an experimental service in the late 1990s has evolved into a sophisticated forecasting system that not only helps fishermen find fish faster but is also being redesigned to protect the very fish stocks it supports.
At the heart of this transformation is the Potential Fishing Zone (PFZ) advisory, developed by the Indian National Centre for Ocean Information Services (INCOIS) in Hyderabad under the Ministry of Earth Sciences. Over the past two decades, the satellite-based forecasting system has helped nearly 14 lakh fishermen reduce the time, fuel consumption and operating cost of locating fish at sea.
Using satellite data on sea-surface temperature and chlorophyll concentration, an indicator of ocean productivity, INCOIS scientists identify waters where fish are likely to aggregate. Initially issued twice a week outside the monsoon season, the advisories are now released daily through mobile apps, satellite communication devices, radio broadcasts, harbour display boards, websites and State-specific Telegram channels in several regional languages.
The economic gains appear considerable. A recent assessment led by INCOIS director T.M. Balakrishnan Nair estimates that PFZ-guided fishing generates net annual benefits worth several billion dollars. In one study, fishermen reported earning an additional ₹18,000 per trip on average, although scientists caution that such estimates carry some uncertainty.
Much of the benefit comes from reducing the time spent searching for fish. PFZ advisories have cut search time by 60-70% for small pelagic shoals and by 30-40% for several commercially important species, enabling fishing trips that once lasted three to five days to often be completed within one or two.
Field validation along India’s coastline has consistently shown higher Catch Per Unit Effort (CPUE) within notified PFZs than outside them. Purse seiners, for instance, averaged 3,260.5 kg per haul within PFZs compared with 1,616.2 kg outside. Similar patterns were observed across ring seines, bottom trawls, gill nets, mid-water trawls and longlines, with field experiments conducted off Odisha, Andhra Pradesh and other coasts confirming the advisories’ effectiveness.
The environmental gains are equally significant. By helping fishermen reach productive fishing grounds faster, PFZ advisories reduce fuel consumption, one of the biggest costs in marine fishing. A study off Kerala recorded fuel savings ranging from 21.5 to 1,293.5 litres per tonne of catch, cutting carbon emissions by 0.06 to 3.45 tonnes. Modelling suggests these benefits could increase substantially if 75% of the fishing fleet adopts the advisories. High-consumption trawlers would provide the largest absolute reductions, while ring seines and gill nets would deliver the greatest efficiency gains.
The system also incorporates safeguards to protect marine ecosystems. Advisories are suspended during statutory fishing bans and are not issued for marine protected areas, turtle nesting sites and other ecologically sensitive regions.
This approach has shaped a new generation of species-specific forecasts. The Yellowfin Tuna Advisory, developed under the SATTUNA project, combines satellite data with fish-tagging information to help longline operators target tuna more precisely. The Hilsa Fishery Advisory (HiFA) for the northern Bay of Bengal uses salinity, ocean currents and machine-learning models to guide fishers towards post-spawning Hilsa while excluding spawning habitats, breeding seasons and a 5-10 km coastal buffer.
Conservation, in this case, is built into the design of an advisory for a species that migrates between marine and freshwater environments to breed.
Technology has also improved how these advisories reach fishermen. The GEMINI (GAGAN Enabled Mariner’s Instrument for Navigation and Information) device and the Android-based SAMUDRA app provide near real-time ocean information while fishermen are still at sea.
The Fishery Information Source Hub (FISH) app goes a step further by allowing users to share catch records, biodiversity sightings and local observations directly with researchers. “This participatory approach combines traditional wisdom with modern ocean science, improving the accuracy and relevance of future advisories,” says Nair.
Scientists, however, caution that current assessments capture only part of the picture, with many users falling outside formal evaluations, while the ecological consequences of wider adoption require further study. The challenge ahead, they say, is to balance greater fishing efficiency with long-term protection of fish stocks and marine ecosystems.
The study also involved INCOIS scientists Dhanya M. Lal, Bhagyashree Dash, Sanjiba Baliarsingh, Alakes Samanta, N. Swetha, Sudheer Joseph and M. Nagaraja Kumar.
Published - July 17, 2026 09:13 pm IST