NOAA Coral Reef Watch Satellite Bleaching Alert System (SBA)

NOAA Coral Reef Watch Satellite Bleaching Alert

5-km Satellite Regional Virtual Stations

Bleaching or no bleaching, please report to your regional network or to Coral Reef Watch!

Alert Changes Summary

Based on data from 19 Mar 2025

No Stress

Watch

Warning

Alert Level 1

Alert Level 2

(↑) or (↓) indicates an increase or decrease in the heat stress level

Alerts are for reef regions, archipelagos or jurisdictions, not for individual data grid points


Atlantic Ocean
Eastern Atlantic
Sao Tome and Principe	↓ Watch
Caribbean
Belize	↑ Watch
Brazil
Abrolhos Reefs, Brazil	↑ Alert Level 2

Pacific Ocean
Polynesia
Pitcairn Islands	↓ Watch
Melanesia
Fiji	↑ Alert Level 1
Western New Caledonia	↑ Warning
Chesterfield Islands	↓ Warning

Southeast Asia
Coral Triangle
West Sulawesi	↓ Watch
South Sulawesi	↓ Watch

Australia
Great Barrier Reef
Northern GBR	↓ Watch
Central GBR	↓ Watch
Northern Coral Sea Islands	↓ Watch
Other Australia Stations
Hamelin Pool	↑ Alert Level 2

Indian Ocean
South Asia
Gulf of Mannar	↑ Watch
Western Indian Ocean
Kenya	↑ Warning
Central Mozambique	↓ Watch
Bassas da India, France	↓ Watch
Southwestern Madagascar	↓ Watch
Northern Mauritius	↑ Alert Level 2

All Station Alert Levels

Google Earth KMZ

5-km Satellite Regional Virtual Station Bleaching Alert Details

Based on data from 19 Mar 2025



Sao Tome and Principe	↓ Watch
Satellite Observations: (description)
Degree Heating Week	0.4°C-weeks
Coral Bleaching HotSpot	0.9°C
Sea Surface Temperature (SST)	29.9°C
SST Anomaly	1.0°C
Maximum Monthly Mean SST Climatology	28.9°C
Most Recent Alert Level Changes:
03/19/2025	Watch
03/02/2025	Warning
01/29/2025	Watch
01/26/2025	No Stress
12/29/2024	Watch
Map and Gauge
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Belize	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.0°C
Sea Surface Temperature (SST)	28.2°C
SST Anomaly	1.4°C
Maximum Monthly Mean SST Climatology	28.9°C
Most Recent Alert Level Changes:
03/19/2025	Watch
12/04/2024	No Stress
10/27/2024	Watch
06/19/2024	Alert Level 2
06/02/2024	Alert Level 1
Map and Gauge
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Abrolhos Reefs, Brazil	↑ Alert Level 2
Satellite Observations: (description)
Degree Heating Week	8.2°C-weeks
Coral Bleaching HotSpot	1.8°C
Sea Surface Temperature (SST)	28.9°C
SST Anomaly	1.8°C
Maximum Monthly Mean SST Climatology	27.0°C
Most Recent Alert Level Changes:
03/19/2025	Alert Level 2
03/02/2025	Alert Level 1
02/12/2025	Warning
02/02/2025	Watch
01/19/2025	Warning
Map and Gauge
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Pitcairn Islands	↓ Watch
Satellite Observations: (description)
Degree Heating Week	4.9°C-weeks
Coral Bleaching HotSpot	0.8°C
Sea Surface Temperature (SST)	27.6°C
SST Anomaly	0.9°C
Maximum Monthly Mean SST Climatology	26.8°C
Most Recent Alert Level Changes:
03/19/2025	Watch
03/05/2025	Alert Level 1
02/26/2025	Warning
02/23/2025	Watch
01/29/2025	Warning
Map and Gauge
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Fiji	↑ Alert Level 1
Satellite Observations: (description)
Degree Heating Week	5.5°C-weeks
Coral Bleaching HotSpot	1.0°C
Sea Surface Temperature (SST)	28.6°C
SST Anomaly	1.1°C
Maximum Monthly Mean SST Climatology	28.4°C
Most Recent Alert Level Changes:
03/19/2025	Alert Level 1
03/09/2025	Watch
02/19/2025	Alert Level 1
01/22/2025	Warning
12/01/2024	Watch
Map and Gauge
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Western New Caledonia	↑ Warning
Satellite Observations: (description)
Degree Heating Week	3.7°C-weeks
Coral Bleaching HotSpot	1.0°C
Sea Surface Temperature (SST)	28.0°C
SST Anomaly	1.5°C
Maximum Monthly Mean SST Climatology	27.2°C
Most Recent Alert Level Changes:
03/19/2025	Warning
03/16/2025	Watch
03/05/2025	Alert Level 1
02/26/2025	Watch
02/19/2025	Alert Level 1
Map and Gauge
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Chesterfield Islands	↓ Warning
Satellite Observations: (description)
Degree Heating Week	3.0°C-weeks
Coral Bleaching HotSpot	1.0°C
Sea Surface Temperature (SST)	28.6°C
SST Anomaly	1.5°C
Maximum Monthly Mean SST Climatology	27.2°C
Most Recent Alert Level Changes:
03/19/2025	Warning
03/09/2025	Alert Level 1
02/09/2025	Watch
02/02/2025	Alert Level 1
01/15/2025	Warning
Map and Gauge
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West Sulawesi	↓ Watch
Satellite Observations: (description)
Degree Heating Week	0.1°C-weeks
Coral Bleaching HotSpot	0.6°C
Sea Surface Temperature (SST)	29.9°C
SST Anomaly	0.9°C
Maximum Monthly Mean SST Climatology	29.2°C
Most Recent Alert Level Changes:
03/19/2025	Watch
03/12/2025	Warning
12/15/2024	Watch
11/13/2024	Warning
10/20/2024	Watch
Map and Gauge
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South Sulawesi	↓ Watch
Satellite Observations: (description)
Degree Heating Week	0.1°C-weeks
Coral Bleaching HotSpot	0.6°C
Sea Surface Temperature (SST)	29.9°C
SST Anomaly	1.1°C
Maximum Monthly Mean SST Climatology	29.3°C
Most Recent Alert Level Changes:
03/19/2025	Watch
03/12/2025	Warning
12/11/2024	Watch
11/27/2024	Alert Level 1
10/30/2024	Warning
Map and Gauge
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Northern GBR	↓ Watch
Satellite Observations: (description)
Degree Heating Week	10.2°C-weeks
Coral Bleaching HotSpot	0.2°C
Sea Surface Temperature (SST)	29.2°C
SST Anomaly	1.1°C
Maximum Monthly Mean SST Climatology	28.7°C
Most Recent Alert Level Changes:
03/19/2025	Watch
03/09/2025	Alert Level 2
03/02/2025	Watch
02/09/2025	Alert Level 2
01/19/2025	Alert Level 1
Map and Gauge
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Central GBR	↓ Watch
Satellite Observations: (description)
Degree Heating Week	7.7°C-weeks
Coral Bleaching HotSpot	0.2°C
Sea Surface Temperature (SST)	28.3°C
SST Anomaly	0.8°C
Maximum Monthly Mean SST Climatology	28.3°C
Most Recent Alert Level Changes:
03/19/2025	Watch
03/09/2025	Alert Level 1
02/26/2025	Watch
02/16/2025	Alert Level 1
02/12/2025	Watch
Map and Gauge
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Northern Coral Sea Islands	↓ Watch
Satellite Observations: (description)
Degree Heating Week	13.1°C-weeks
Coral Bleaching HotSpot	0.6°C
Sea Surface Temperature (SST)	28.7°C
SST Anomaly	1.2°C
Maximum Monthly Mean SST Climatology	28.3°C
Most Recent Alert Level Changes:
03/19/2025	Watch
03/09/2025	Alert Level 2
03/02/2025	Watch
01/22/2025	Alert Level 2
01/05/2025	Alert Level 1
Map and Gauge
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Hamelin Pool	↑ Alert Level 2
Satellite Observations: (description)
Degree Heating Week	25.9°C-weeks
Coral Bleaching HotSpot	0.7°C
Sea Surface Temperature (SST)	26.4°C
SST Anomaly	0.9°C
Maximum Monthly Mean SST Climatology	25.9°C
Most Recent Alert Level Changes:
03/19/2025	Alert Level 2
03/16/2025	Watch
01/12/2025	Alert Level 2
12/25/2024	Alert Level 1
12/11/2024	Warning
Map and Gauge
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Gulf of Mannar	↑ Watch
Satellite Observations: (description)
Degree Heating Week	0.0°C-weeks
Coral Bleaching HotSpot	0.2°C
Sea Surface Temperature (SST)	30.0°C
SST Anomaly	0.9°C
Maximum Monthly Mean SST Climatology	30.1°C
Most Recent Alert Level Changes:
03/19/2025	Watch
11/27/2024	No Stress
11/17/2024	Watch
11/13/2024	No Stress
11/06/2024	Watch
Map and Gauge
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Kenya	↑ Warning
Satellite Observations: (description)
Degree Heating Week	0.2°C-weeks
Coral Bleaching HotSpot	1.0°C
Sea Surface Temperature (SST)	29.7°C
SST Anomaly	1.2°C
Maximum Monthly Mean SST Climatology	28.8°C
Most Recent Alert Level Changes:
03/19/2025	Warning
03/05/2025	Watch
01/05/2025	No Stress
12/22/2024	Watch
12/15/2024	No Stress
Map and Gauge
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Central Mozambique	↓ Watch
Satellite Observations: (description)
Degree Heating Week	7.6°C-weeks
Coral Bleaching HotSpot	0.2°C
Sea Surface Temperature (SST)	29.0°C
SST Anomaly	0.3°C
Maximum Monthly Mean SST Climatology	28.6°C
Most Recent Alert Level Changes:
03/19/2025	Watch
02/23/2025	Alert Level 1
01/22/2025	Warning
01/05/2025	Watch
12/29/2024	Warning
Map and Gauge
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Bassas da India, France	↓ Watch
Satellite Observations: (description)
Degree Heating Week	10.1°C-weeks
Coral Bleaching HotSpot	0.0°C
Sea Surface Temperature (SST)	28.1°C
SST Anomaly	-0.1°C
Maximum Monthly Mean SST Climatology	28.6°C
Most Recent Alert Level Changes:
03/19/2025	Watch
03/09/2025	Alert Level 2
03/05/2025	Watch
02/19/2025	Alert Level 2
02/09/2025	Alert Level 1
Map and Gauge
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Southwestern Madagascar	↓ Watch
Satellite Observations: (description)
Degree Heating Week	14.5°C-weeks
Coral Bleaching HotSpot	0.0°C
Sea Surface Temperature (SST)	29.5°C
SST Anomaly	0.0°C
Maximum Monthly Mean SST Climatology	29.0°C
Most Recent Alert Level Changes:
03/19/2025	Watch
03/05/2025	Alert Level 2
03/02/2025	Watch
01/19/2025	Alert Level 2
01/08/2025	Alert Level 1
Map and Gauge
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Northern Mauritius	↑ Alert Level 2
Satellite Observations: (description)
Degree Heating Week	8.1°C-weeks
Coral Bleaching HotSpot	1.0°C
Sea Surface Temperature (SST)	29.7°C
SST Anomaly	1.1°C
Maximum Monthly Mean SST Climatology	28.6°C
Most Recent Alert Level Changes:
03/19/2025	Alert Level 2
02/23/2025	Alert Level 1
01/29/2025	Warning
12/01/2024	Watch
11/24/2024	Warning
Map and Gauge
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Summary Notes

No Stress	No heat stress	HS <= 0
Watch	Low heat stress	0 < HS < 1
Warning	Heat stress accumulating	HS >= 1 0 < DHW < 4
Alert Level 1	Bleaching expected	HS >= 1 4 <= DHW < 8
Alert Level 2	Significant bleaching expected; mortality likely	HS >= 1 DHW >= 8

Bleaching alerts are only generated when there is a stress level change for a station.
The alerts are generated for affected reef regions, archipelagos, and/or jurisdictions, not for individual data grid points.
Your bleaching observations (including observations of no bleaching) are greatly
appreciated. Observations can be sent to coralreefwatch@noaa.gov and/or entered online via Coral Reef Watch.
Should you have any questions or feedback on our Satellite Bleaching Alert email system, please send an email to coralreefwatch@noaa.gov.
To view, change (stations, email type, etc), or end your subscription, please visit the Coral Reef Watch Satellite Bleaching Alert website.
Please do not reply to this email address.

Disclaimer

20-Mar-2025

Eastern Atlantic

Caribbean

Brazil

Polynesia

Melanesia

Coral Triangle

Great Barrier Reef

Other Australia Stations

South Asia

Western Indian Ocean