Persistent El Niño could disrupt Indian Ocean marine ecosystems, scientists warn
Scientists at India’s INCOIS say current El Niño conditions may persist until at least April 2027, raising the risk of marine heatwaves and ecological damage across the northern Indian Ocean. They warn that reduced coastal upwelling could affect fish habitats, productivity and catches of key species.
Current El Niño conditions are likely to remain dominant until at least April 2027 and could adversely affect marine ecosystems, scientists at the Indian National Centre for Ocean Information Services said on Monday. INCOIS estimated the probability of El Niño conditions continuing through that period at between 80% and 100%. El Niño is associated with warmer sea-surface temperatures in the central and eastern equatorial Pacific and can influence weather and ocean conditions far beyond that region.
The scientists said the phenomenon can weaken the Indian summer monsoon and affect rainfall patterns, with consequences for agriculture and the economy. It can also produce stronger and longer-lasting marine heatwaves in the northern Indian Ocean. Such heatwaves may damage coral reefs, disrupt marine ecosystems and affect fisheries.
The scientists said El Niño had strengthened and was expected to remain strong from August 2026 through March 2027. Its persistence is expected to bring higher sea-surface temperatures, increased heat in the upper ocean, stronger water-column stratification and widespread marine heatwaves. Moderate to extreme heatwave conditions are already affecting large parts of the Arabian Sea and the Bay of Bengal, while the affected area has expanded compared with 2025.
The ongoing conditions have also significantly reduced coastal upwelling along India’s west coast. Upwelling brings nutrient-rich water to the surface and supports marine productivity. Its reduction, combined with warmer waters, could damage fish habitats and lower productivity.
P.A. Francis, a senior scientist and head of INCOIS’s Ocean Modelling and Data Assimilation Centre, said historical fishery records since 1950 showed that marine catches across the Indian Ocean generally declined during El Niño phases, although effects differed by region. Studies covering 1985 to 2023 also found negative effects on the maturation and recruitment of Indian oil sardine and Indian mackerel in Kerala and Karnataka.
Francis said fish populations could be pushed into deeper or more northerly waters, while El Niño could also alter extreme wave conditions.
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