Marshall, 2002:

2001/2002 Mass bleaching event

The unusually warm water experienced over the summer of 2001/2002 has lead to a mass bleaching event on the GBR. This is the second mass-bleaching event to affect the GBR in five years. While most reefs have escaped without extensive death of corals, the extent of bleaching indicates that the majority of reefs within the Great Barrier Reef Marine Park were exposed to stressful conditions. The potential for bleaching to cause severe ecological damage to entire coral reef ecosystems was seen during the 1998 bleaching event at several locations worldwide, including the Maldives, Tanzania and Sri Lanka. In both recent bleaching events (1998 and 2002), the GBR has been fortunate to escape with extensive mortality of corals seen at only a few inshore reefs. 

Keppel Islands, 2006

Coral communities that experienced mild bleaching are expected to regain their zooxanthellae and survive, with few cases of mortality. Sites where bleaching was both extensive and severe (Far Southern Region) were closely monitored for survival and mortality rates in the months that followed the surveys presented in this report. Surveys in June 2006 estimated coral mortality among the Keppel Islands sites to be 31 per cent, with over 33 per cent unbleached (having regained their zooxanthellae) and 10 per cent still showing signs of bleaching.  A further survey by the Australian Institute of Marine Science in August 2006 recorded 40 per cent mortality of corals in the Keppel Islands.  Importantly, reefs in the Keppel Island region have experienced bleaching before with up to 100 per cent of corals affected during the 1998 and 2002 bleaching events.  Following these events though survival rates were far higher than in the 2006 event and very little mortality was observed.