Conditions as at 20 December 2009

Current bleaching forecast

On the basis of seasonal temperature trends, the risk of widespread coral bleaching in the Great Barrier Reef region is currently rated as LOW.
 

Sea surface temperature (SST) anomaly forecasts for the Great Barrier Reef Marine Park suggest that SSTs are expected to remain at or below the long-term summer averages during December 2009 and January 2010.  These forecasts, produced by the Bureau of Meteorology (BOM) and the Australian Commonwealth Scientific and Research Organisation (CSIRO), indicate that conditions are unlikely to cause coral bleaching in early summer. However the forecasts do indicate above average SSTs in the southern Great Barrier Reef between February and April 2010, which could elevate the bleaching risk in this area.

The risk of severe coral bleaching in the southern Great Barrier Reef may also be heightened by the damage caused by Tropical Cyclone Hamish in March 2009, and the high SSTs (+1-2°C above average) in the region in winter 2009. Research indicates that cumulative stress such as physical damage and warm winter SSTs may predispose corals to bleaching and disease. Consequently the legacy of impacts from last summer, coupled with the high winter temperatures may increase the susceptibility of some sections of the Reef to coral bleaching over the coming summer.

Predicting coral bleaching

Current bleaching status

Overall, reports from the BleachWatch network indicate that the current levels of coral bleaching across the entire Great Barrier Reef are LOW.

Each summer, the Great Barrier Reef Marine Park Authority works with the BleachWatch network of volunteers to detect any early signs of coral bleaching on the Reef. A number of Bleachwatch reports have already been received for summer 2009/10, including observations of coral paling at a small number of locations.  Paling can lead to coral bleaching if stressful conditions continue, however if these conditions improve then corals can recover. Given the potential for increased bleaching susceptibility outlined above, conditions at these locations will be monitored closely.

For more information on BleachWatch program contact the BleachWatch coordinator at bleachwatch@gbrmpa.gov.au. 

Report signs of coral bleaching
Causes of coral bleaching
Monitoring coral bleaching