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### The Great Barrier Reef Marine Park Authority
http://www.gbrmpa.gov.au/

### Summary

- In 2002 the Great Barrier Reef experienced a mass bleaching event that was more severe than the event of 1998. This makes the bleaching event of 2002 the worst ever recorded for the GBR.
- Underwater surveys found that few reefs had completely escaped the effects of coral bleaching. However, the majority of reefs appear likely to survive the bleaching event with only minimal coral death. Extensive mortality was recorded on only a few of the inshore reefs surveyed, where up to 90% of corals were dead.
- The first signs of substantial bleaching were reported in January 2002. The worst of the bleaching event was over by April 2002.
- In response to this event, the Great Barrier Reef Marine Park Authority implemented the world’s most comprehensive survey of coral bleaching in collaboration with AIMS, CRC Reef and NOAA.
- Aerial surveys found that coral bleaching was evident from the air at almost 60% of the 641 reefs surveyed.
- Inshore reefs were more severely affected by bleaching, as was the case in 1998. However, in 2002 many offshore reefs were also affected.
- The effects of bleaching were highly variable, varying from negligible to severe, even between reefs that were similar distances offshore. Bleaching was generally most severe in shallower water, and strong patterns of species susceptibilities were generally evident across the sites surveyed.
- Further surveys are planned for later in 2002 when the fate of corals that bleached during the Summer will be studied further.
- Should warm water events increase in severity, duration, or frequency in the future, coral bleaching is likely to become increasingly severe on the GBR.

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