| Regions | Spread of Marine Heat Wave (% of Area) | Remarks | ||
|---|---|---|---|---|
| Watch | Alert | Warning | ||
| Arabian Sea | 22% | 09% | 01% | • Arabian Sea: Major Watch–Alert–Warning spread along Gujarat, Maharashtra, Goa, Karnataka, Kerala and Lakshadweep Islands, extending toward Oman — Might Impact: Coral reef stress, pelagic fisheries shift, productivity reduction. |
| Bay of Bengal | 19% | 03% | -- | • Bay of Bengal: Major Watch–Alert–Warning concentrated over Andaman and Nicobar Islands and eastern basin toward Myanmar and Thailand — Might Impact: Coral bleaching risk, reef ecosystem stress, altered plankton productivity. |
| Southern Indian Ocean | 06% | 03% | 01% | • Southern Indian Ocean: Persistent Alert–Warning south of Madagascar, Mauritius and Seychelles — Might Impact: Open-ocean productivity decline and tuna migration shift. |
| South China Sea | 03% | 02% | 02% | • South China Sea: Repeated Alert–Warning along Vietnam, Philippines and Malaysia — Might Impact: Coral bleaching and reef fish habitat stress. |
| Red Sea & Gulf of Aden | 08% | 01% | -- | • Red Sea & Gulf of Aden: Limited Watch–Alert near Saudi Arabia, Yemen and Djibouti — Might Impact: Localized coral reef stress. |
| Persian Gulf | -- | -- | -- | • Persian Gulf: No significant MHW observed during this period. |
Background: The Indian National Centre for Ocean Information Services (INCOIS) is a research organization under the Ministry of Earth Science (MoES) Government of India, has carried out research and development on Marine Heat Wave based on the prolonged anomalous temperature above the 90th percentiles of daily climatology calculated using OISST data over the Indian Ocean including south China sea. The intensity of MHW and its different categories of products such as ‘Watch’ (SST anomaly from 0 to 10), ‘Alert’ (1-2) andWarning’ (>2oC) were generated dailyand hosted on web-GIS interface https://incois.gov.in/oceanservices/mhw/index.jsp. The study area of this service is dividedinto six ocean basins (Arabian Sea, Bay of Bengal, Persian Gulf, Red Sea, southern Indian Ocean and South China Sea) and fourteen sectors off the Indian states (Gujarat, Maharashtra, Goa, Karnataka, Kerala, Lakshadweep, South Tamil Nadu, North Tamil Nadu, South Andhra Pradesh, North Andhra Pradesh, Odisha, West Bengal, Andaman and Nicobar Islands) for sectoral analysis. INCOIS also carried out on the intensity of MHW and its impact on Marine ecology such as coral reefs, seagrass, seaweeds, fishery etc. with their adverse impact on biodiversity and species shifting due to future climate change.
Based on daily MHW advisories of the past seven days, a weekly summary report was generated and presented in the form of a bulletin comprising a summary of the MHW status in each ocean basin. This will provide an overview of the MHW status in different ocean basins that help stockholders such as ecologists, fishermen, coastal managers, tourists, ocean researchers, etc.
