The Indian National Centre for Ocean Information Services (INCOIS) has warned that the ongoing El Nino event could significantly reduce fish catch along India's coastlines, particularly in the Bay of Bengal and the Arabian Sea, according to the agency's first specialised El Nino bulletin released on Tuesday, 23 June 2026. The bulletin marks the beginning of a dedicated series aimed at alerting maritime sectors to the cascading effects of the developing climate phenomenon.

El Nino Peak and Ocean Temperature Outlook

According to the bulletin, the El Nino event is still developing and is expected to peak during the winter season between November 2026 and January 2027. As a consequence, sea surface temperatures across the Indian Ocean are projected to remain above normal through April or May 2027, placing sustained thermal pressure on marine ecosystems in the northern Indian Ocean.

Impact on Marine Ecosystems and Fish Catch

The bulletin warns that the marine ecosystem across both the Arabian Sea and the Bay of Bengal is likely to face significant thermal stress, particularly between March and May 2027. This elevated ocean heat is forecast to trigger increased coral reef bleaching, more frequent marine heat waves, and a notable reduction in catch volumes — especially for sardine and mackerel species.

The decline in catch is attributed to two key mechanisms: fish stocks migrating toward cooler, more suitable habitats, and a drop in fish recruitment — meaning fewer juvenile fish surviving to harvestable size. Additionally, INCOIS has flagged that fish may fail to reach commercially viable sizes due to altered marine environmental conditions driven by the developing El Nino.

Coastal Erosion and Sea State Warnings

The east coast faces a different set of risks. The bulletin states that sea conditions in the Bay of Bengal will remain rough through the monsoon season, raising the probability of increased coastal erosion and flooding along India's east coast. In contrast, the Arabian Sea and the west coast are expected to experience calmer-than-usual sea states, which could widen the operational window for marine sector activities and reduce coastal inundation risks on the west coast during the current monsoon season.

INCOIS Advisory and Next Steps

The first specialised bulletin was formally released by Konda Vishweshwar Reddy, Bharatiya Janata Party (BJP) Member of Parliament from Chevella, Telangana. INCOIS has advised all maritime operators to closely monitor its ongoing alerts, warnings, and advisories. The next specialised El Nino bulletin is scheduled for release in the second week of July 2026.

This bulletin series represents a proactive step in translating large-scale climate signals into sector-specific guidance — a critical need for India's fishing communities, coastal administrators, and maritime operators who remain directly exposed to El Nino's downstream effects.