Introduction

Hard coral disease is abundant and diverse on the Great Barrier Reef. Yet little is known about its role in shaping the coral reef community. Perhaps, even more surprisingly, it is only in recent decades that coral disease has become a topic of interest to reef ecologists generally. This is despite the fact that the first disease of reef building corals was described in the Caribbean some forty years ago¹. Over the next thirty years only four new diseases were documented (all in the Caribbean).

However this changed with the realization that in parts of the Caribbean populations off hard corals were being decimated by disease^2,3,4. In turn this led to an increase in research and as a result there was a proliferation of reports with a total of between 18 and 29 new diseases described by 2002^5,6 and a new appreciation of the important role disease can play in structuring coral communities.

The Caribbean experience has been reflected to some extent in the Indo-Pacific where there was an initial complacency towards the threat posed, despite coral disease being first reported from the Indo-Pacific in 1985⁷.

On the Great Barrier Reef the first recorded occurrence of disease was in the early nineties8,9 and since this time, and particularly in recent years, there has been increasing attention given to the phenomenon. Though to date coral disease has not had a large-scale impact on reefs in the GBR (as opposed to the Caribbean "hot spot") there is no guarantee this will be the case in the future. The AIMS long-term monitoring program (LTMP) has recognized the important role disease plays in shaping coral communities and has been conducting disease surveys since the late nineties. These surveys detected a large increase in the number of coral colonies affected by signs of disease on the GBR in 2003 that provided impetus for further research into the phenomenon.

Image 1 AIMS divers routinely visually search for signs of coral mortality caused by disease and other factors while conducting surveys of corals and other benthic organisms. There is a body of evidence that suggests the prevalence of hard coral disease and marine diseases in general (particularly in the Caribbean) has increased over the last twenty years. Photograph AIMS LTMP Click here for a larger view

Summary

• Diseases are an integral component of the reef ecosystem though the exact role they play in the reef community is still to be elucidated.
• At least seven clearly identifiable diseases of hard corals are recognized on the GBR but there is likely to be more discovered as research into coral disease on the GBR gains momentum.
• Incidence of disease is generally low with the exception of 2003 when a spike in disease activity (particularly white syndrome) was identified on the GBR.
• White syndrome is the most commonly encountered disease on the GBR and appears to affect mainly Acropora spp. hard corals and in a density dependent manner.
• The Cooktown Lizard Island and Capricorn-Bunker sectors are the regions of the GBR where most disease activity has been observed by the LTMP.

 CONTENTS
   Introduction | Black Band Disease | White Syndrome | Skeletal Eroding Band
  Brown Band | Skeletal tumours | Atramentous necrosis
  Porites Pinking | Vibrio Induced Bleaching
  References | Content navigation