Coral disease

Coral diseases are normal in reef ecosystems. Like all animals, corals can be affected by diseases, especially if they are under stress. For example, corals that survive bleaching caused by heat stress are more susceptible to disease.

To date, coral disease outbreaks on the Great Barrier Reef have not caused widespread damage. Between 1995 and 2009 only 6.5 per cent of the mortality recorded on the Great Barrier Reef was attributed to coral disease. Experience in other countries has shown that the incidence of disease is higher on coral reefs that have become degraded by human activities.

Climate change, stress and coral disease

The risk of coral disease outbreaks on the Great Barrier Reef is likely to increase as the impacts of climate change place reefs under additional stress. Rising sea surface temperatures may increase the frequency and severity of coral disease outbreaks throughout the Great Barrier Reef Marine Park.

On regional scales, disease outbreaks can occur following extensive coral damage caused by severe storms or exposure to fresh water, nutrient, sediment and pesticide runoff that reaches the Reef.

On individual coral reefs, pollutants and physical injury to corals may also contribute to an increased incidence of disease at local scales.

Management actions

The GBRMPA works closely with research partners and key stakeholders to better understand and manage the risk of coral disease outbreaks. As part of our Reef Health Incident Response System, we have a Coral Disease Response Plan for detecting and responding to coral disease on the Great Barrier Reef.

The resilience of coral reefs to coral disease can be improved by reducing the impact of other threats such as:

  • Improving water quality of the Reef by reducing the amount of pesticide, nutrient and sediment run-off
  • Educating Reef users about best practices in the Marine Park
  • Reducing interference at reefs recovering from other climatic events such as storms.