El Nino is heating up the oceans. Could India's fish supplies be at risk?

CMFRI warns that strengthening El Niño conditions could reduce India's oil sardine availability in 2027. The concern is linked to warming spreading from the Pacific toward the northern Indian Ocean. It does not mean India's entire fish supply will collapse, but it could pressure an important fishery and the livelihoods connected to it.

The likely mechanism is increased ocean heat. CMFRI says El Niño-related warming could intensify marine heatwaves. INCOIS also warns that thermal stress in the Arabian Sea and Bay of Bengal may affect sardines and Indian mackerel. Fish could move toward cooler or more suitable habitats, become scarcer in fishing grounds, or fail to reach their usual size.

The possible reduction could reach the northern Indian Ocean around April–May 2027. Its consequences will depend on how large the decline becomes, alongside demand, alternative supplies, fishing pressure and fishers' ability to adapt. Monitoring temperatures, productivity and landings will be crucial.

Indian oil sardines and Indian mackerel are the main Indian species identified as potentially affected by warming. These small pelagic fish support fishing activity, coastal markets and affordable seafood supplies. Their response matters because changes in abundance, location or size can quickly affect catches and fishing incomes.

INCOIS warns that the Arabian Sea and Bay of Bengal could face thermal stress. El Niño-related warming may also affect the northern Indian Ocean, where the possible sardine reduction could become evident around April–May 2027. Warmer conditions can push fish toward more suitable habitats, reduce their presence in familiar fishing grounds or limit their usual growth.

The article also highlights Indian oil sardine fisheries along with small-pelagic fisheries on the Malabar Coast. Research has linked changes in sardine and mackerel landings to environmental conditions. Still, the fish response will reflect several pressures, including fishing intensity and broader ocean warming.

El Niño begins with unusual warmth in the central and eastern tropical Pacific, but its consequences can extend far beyond that region. The article links strengthening conditions to warming in the northern Indian Ocean, where Indian sardine and mackerel fisheries may be affected. This creates a chain from ocean conditions to fishing grounds, coastal livelihoods and seafood markets.

Peru's anchoveta fishery provides a wider example. El Niño can weaken upwelling, reducing plankton and fish production along South America's Pacific coast. A major anchoveta catch decline can reduce fishmeal supplies. Because fishmeal is used in aquaculture feed, costs may rise for fish farmers elsewhere.

In India, lower sardine or mackerel availability could reduce fishing incomes and affect coastal markets and affordable fish supplies. Price effects are uncertain. They depend on the decline's size, consumer demand, alternative supplies and how effectively fishers and traders adapt.

Reduced sardine and mackerel catches would affect more than the boats that land them. Fishing incomes could fall when fish become less abundant in familiar grounds. Coastal markets might receive less supply, and consumers could face less access to affordable fish. The article presents these as possible pressures, not a guaranteed collapse.

The mechanism is straightforward. Warming and marine heatwaves can make usual habitats less suitable. Fish may move elsewhere, become harder to catch or fail to reach their usual size. A smaller catch means less product entering markets. If demand remains strong while alternatives are limited, traders may pass higher costs on to consumers.

The eventual price change is uncertain. It depends on the scale of the decline, consumer demand, alternative supplies and the ability of fishers and traders to adapt. Long-term warming, overfishing and habitat degradation could also compound El Niño's effects.

El Niño occurs when surface waters in the central and eastern tropical Pacific become unusually warm. This is not simply a local temperature change. The added heat alters ocean circulation and atmospheric patterns, changing how water, winds and weather behave across connected parts of the climate system.

One important consequence is weaker upwelling. Winds normally help lift cold, nutrient-rich deep water toward the surface. When El Niño disrupts this process, less nourishment reaches surface waters along South America's Pacific coast. Phytoplankton, which form the base of the marine food chain, may grow less strongly. That reduces food available to fish and other marine animals.

The effects can also matter for India. The article reports that strengthening El Niño conditions could contribute to warmer waters and marine heatwaves in the northern Indian Ocean. This may affect sardine and mackerel habitats, catches and coastal livelihoods. El Niño is therefore both an ocean event and a wider climate influence.

Ocean upwelling is the movement of cold, nutrient-rich water from deeper layers to the surface. Winds help drive this process. It matters because surface waters need those nutrients to support phytoplankton, microscopic organisms that form the base of the marine food chain.

During El Niño, warming can disrupt the winds and circulation that support upwelling. Along South America's Pacific coast, weaker upwelling means fewer nutrients reach the sunlit surface. Phytoplankton growth can decline, leaving less food for fish and other marine animals. The article describes this as a pathway through which warming can starve marine life.

The effects can build through the ecosystem. A December 2025 study of Peru's anchoveta fishery found that powerful El Niño events in 1982–83 and 1997–98 disrupted the timing between plankton blooms and fish larvae feeding. Poor timing can reduce larval survival and eventually fishing yields.

Fish catches respond to many forces, so every change cannot be assigned to El Niño. The article points to research on Indian oil sardines and Malabar Coast small-pelagic fisheries that examined environmental and human pressures. Catch fluctuations may reflect several influences acting together rather than one climate event.

Long-term ocean warming and marine heatwaves can alter habitats and create thermal stress. Overfishing can reduce populations or increase pressure on already changing stocks. Habitat degradation can remove or damage places fish use. These pressures may compound natural climate variability, making catches harder to interpret and fisheries harder to manage.

That is why researchers and agencies emphasize tracking ocean temperatures, marine productivity, fish habitats, fishing pressure and landings together. Better predictions of suitable sardine habitats are needed. For India, continued monitoring will help distinguish El Niño-related effects from longer-term environmental and human impacts.