Disease occurs naturally in all living systems, so it is expected to be part of the Great Barrier Reef ecosystem.

Australian Institute of Marine Science researchers recently reported coral diseases were responsible for 6.5 per cent of coral death recorded on the Great Barrier Reef between 1995 and 2009.

To date, coral disease outbreaks have not caused as much widespread damage to the Great Barrier Reef as they have on some reefs around the world.

Seven coral diseases have been observed on the Great Barrier Reef. The AIMS long term monitoring and GBRMPA Eye on the Reef programs collect data on White Syndromes and Black Band Disease. GBRMPA also collects data on Brown Band and ‘other’ coral diseases.

These diseases have the fastest rates of progression and can cause considerable mortality once established.

The causes of each are also known:

The prevalence of White Syndromes and Black Band Disease increase with higher temperatures, and hence they are predicted to become more prevalent as a result of climate change.

Skeletal Eroding Band, whilst regularly observed during disease surveys, appears to be limited to a relatively narrow range of species and often only causes minor damage. Atramentous Necrosis ‘Black Death’ has often been recorded on inshore reefs affected by flood and rainfall driven low salinity stress.

Coral disease and climate change

Coral diseases can cause extensive coral mortality in reef ecosystems. Coral disease can often cause the death of coral that has been weakened from other disturbances such as bleaching, flood plumes and cyclones.

The Great Barrier Reef Outlook Report has identified these events may be more frequent under the changing climate; as such the incidence of coral disease may be increasing in some areas.

Whilst disease is a normal part of the coral life cycle, there is increasing evidence that human related activities like poor water quality due to runoff and localised anchor damage on reefs can erode coral health.