Kochi: Finding a good fishing ground could soon be less of a gamble, with satellites offering fishermen clues about where the fish are likely to be. By tracking changes in ocean colour, temperature and wind patterns, scientists are learning to read the sea from space and identify waters that are more likely to yield a good catch.

India’s ocean-observation satellites are also helping track El Niño and monitor changes in marine productivity, said N Aparna, Deputy Director of the National Remote Sensing Centre (NRSC) under the Indian Space Research Organisation (ISRO). Speaking at an international symposium hosted by the ICAR-Central Marine Fisheries Research Institute (CMFRI) in Kochi on Wednesday, she said fish catches in satellite-identified potential fishing zones were found to be 1.5 to four times higher than in areas outside the recommended zones.

The technology uses data from the Ocean Colour Monitor-3 (OCM-3), aboard ISRO’s EOS-06 satellite, to track changes in chlorophyll-a, an indicator of ocean productivity. These changes offer scientists clues about the availability of phytoplankton, tiny marine organisms that form the base of the ocean food chain, and help identify potential fishing grounds.

The satellite’s observations are also being combined with wind measurements to study how El Niño affects ocean productivity. Scientists can use the data to understand how changing winds influence the movement of nutrient-rich water, which in turn affects marine life.

The technology comes at a time when the seas are becoming increasingly difficult to predict. Warming waters, marine heatwaves, coral bleaching, harmful algal blooms and shifting fish populations are posing growing challenges to marine ecosystems and fishing communities.

These concerns took centre stage at the three-day TREVOR SAFARI (Societal Applications in Fisheries and Aquaculture using Remote Sensing Imagery) symposium, which began at CMFRI on Wednesday. More than 300 scientists and experts from 30 countries are attending the event to explore how satellite technology, artificial intelligence and ocean observations can help track changes in marine ecosystems and provide timely warnings

John A Gittings of the National and Kapodistrian University of Athens, Greece, said extreme climate events, particularly marine heatwaves, were driving unusual changes in marine productivity across the world's oceans. Such events can alter the abundance, distribution and composition of marine organisms, making continuous ocean monitoring essential.

Inaugurating the symposium, Sophie Seeyavae, CEO of the UK-based Partnership for Observation of the Global Ocean (POGO), stressed the need to strengthen ocean-observation systems to improve fishing-zone forecasts, detect harmful algal blooms and predict marine heatwaves. Reliable weather and sea-condition alerts are equally important to protect fishing communities, she said.

POGO has trained nearly 1,500 early-career ocean scientists from 102 countries to strengthen global ocean-observation capabilities, Seeyavae added.

The symposium is jointly organised by CMFRI, the Department of Chemical Oceanography at Cochin University of Science and Technology (CUSAT), the Trevor Platt Science Foundation and the Marine Biological Association of India.

CUSAT Vice-Chancellor M Junaid Bushiri presided over the inaugural function. CMFRI Director Grinson George, Plymouth Marine Laboratory’s Shubha Sathyendranath and symposium convenor Shaju S S also spoke.