CONTENTS
-
Description and status of
commonly recognized coral
diseases on the GBR
 Introduction
Black
Band Disease
White
Syndrome
Skeletal
Eroding Band
Brown Band
Skeletal
tumours
Atramentous
necrosis
Porites
Pinking
Vibrio
Induced Bleaching
References
Content
navigation
Research
 Coastal
processes
Conservation
& biodiversity
- Biodiversity
assessment
-
Environmental change
and impacts
- Status
and trends
Marine
biotechnology
Reef monitoring
 Index
Project information
Reef issues
Data
animations
Survey archives
Survey results
Reef
by name
Reef
by location
Biodiversity surveys
Cairns
fringing reefs
Resources
 ProjectNET
for schools
Links
to relevant sites
Research
plan 2007-11
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Coral Diseases
on the Great Barrier Reef
Patterns of distribution and changes
in abundance
of Hard Coral Disease
White Syndrome
"White" type diseases were first described in the Caribbean as
far back as the late seventies with the initial discovery of White
Plague Type I disease in 197720.
This was soon followed by an ever-growing list of other "white" type
diseases identified by differing signs of mortality on affected
corals. These include Shut Down Reaction21
(1977), White Band Type I22
(1982), White Pox23 (1996),
White Plague Type II24
(1998), White Band Type II25
(1998), Skeleton Eroding Band26
(1999) and White Plague Type III27
(2001). With the exception of skeleton eroding band disease, these
were all described from the Caribbean.
At present there is no known relationship between the "white"
diseases described from the Caribbean and those encountered on the
GBR.
| This is
because pathogens infecting GBR corals have not been isolated
and compared to those producing white syndromes in the
Caribbean. The term
‘white-syndrome" (WS) was coined by the AIMS LTMP in recognition
of the difficulty in diagnosing a disease(s) of unknown
pathology based simply on visual field characters or signs.
Typically WS is expressed on a coral as a white band sharply
cutting across live coral tissue with a clear area of necrosis
where the dead white coral skeleton and the living coral colony
meet (Image 4).
The progression of the band is
generally slow enough that an area of coral with an increasing
density of turf algae is seen, as you look further away from the
freshly dead white part of the colony. Within this general
pattern the symptoms can vary considerably depending on the
progression of the disease and the amount of the colony it
infects.
The LTMP has been collecting data
on WS since 1999 and despite the fact that many "white" diseases
had been described from the Caribbean, a lack of research into
diseases of corals on the GBR means that there remains great
difficulty relating symptoms observed on corals on the GBR with
their counterparts in the Caribbean.
In contrast to BBD, WS is
relatively common on the GBR and is usually associated with the
fast growing Acropora spp. hard corals (pers obbs). LTMP
data shows a fluctuation in the presence of the disease on the
GBR over time and that in 2003 there was a large spike in the
occurrence of WSD on the GBR
(Graph 5). |
Image 4 Tabulate Acropora sp. hard coral colony
showing the typical signs associated with White Syndrome.
These are in order, a line of recently dead necrotic tissue
where the disease is active, a line of white denuded coral
skeleton that has been recently killed, and a following area
of increasingly darkened dead coral as filamentous algae
begins to grow on the dead part of the colony.
Photograph AIMS LTMP
Click here for a larger view
Image 5 Photograph of a massive Goniastrea sp. hard
coral showing the typical signs of white syndrome.
Photograph AIMS LTMP
Click here for a larger view
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Fortunately this increase was short lived and has not continued
in subsequent years. The exact reason(s) for this apparent increase
in the incidence of the disease is not known though it was apparent
in all sectors of the reef surveyed with the exception of the
Townsville sector that has historically recorded the lowest
incidence of WS.
Analysis of data collected by the LTMP since 1999 indicates that
there is clear evidence for a significant relationship between the
occurrence of white syndrome on the log scale and coral cover in
each year (i.e. increases in coral cover are associated with a
proportional increase in white syndrome disease). Given this result
it is not surprising that much of the observed mortality was
observed in areas characterised by a high cover of tabulate
Acropora spp. hard corals particularly in the Cooktown/Lizard
Island sector to the north and Capricorn –Bunker sector to the south
(Graph 6).
Of particular interest is the strong cross-shelf pattern in
occurrence of WS that is far more common on outer shelf reefs than
midshelf and inshore reef
(Graph 7). This is in complete contrast to
the distribution of BBD. The lack of anthropogenic impacts to these
relatively isolated reefs suggests that changes in WS abundance are
unlikely to be driven by terrestrial sources of pollution or other
human activities. Rather changes in abundance would appear to be
driven by simple changes in coral cover. For instance increasing
coral cover would be reflected in increased occurrence of WS through
easier disease transmission or susceptibility through crowding or as
colonies age6. In terms of
presence around the reef the reef perimeter analysis showed no
evidence for differences in the occurrence of WS among zones
(Graph 8).
This is despite the fact that coral cover is generally lower on the
back reef.
Graph 5. Mean (SE) number of colonies recorded as showing
signs of WSD per survey reef from 2000 to 2005.
Graph 6. Mean (SE) number of colonies recorded as showing
signs of WSD per survey reef for each of the six LTMP survey
sectors. CL = Cooktown/Lizard Island, CA = Cairns, TO =
Townsville, WH = Whitsunday, SW = Swain, CB = Capricorn-Bunker.
Graph 7. Mean (SE) number of colonies recorded as showing
signs of WSD per shelf position.
Graph 8. Presence absence data recorded during manta
tow surveys. Although WSD appears to be more commonly
encountered on the front reef slope this is not significant
(Pearson Chi-square P = 0.91).
CONTENTS
Introduction | Black
Band Disease | White
Syndrome | Skeletal
Eroding Band
Brown Band | Skeletal
tumours | Atramentous
necrosis
Porites
Pinking | Vibrio
Induced Bleaching
References |
Content navigation
For further information contact
Ian Miller, AIMS
Telephone: +61 7 4753 4471
Email:
i.miller@aims.gov.au
December 18, 2008
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