Description and status of
commonly recognized coral
diseases on the GBR
to relevant sites
on the Great Barrier Reef
Patterns of distribution and changes
of Hard Coral Disease
Skeletal Eroding Band
Skeletal Eroding Band (SEB) is somewhat unique in that it is a
disease of hard corals that was first found in the Indo-Pacific26,28
and so far has not been described from the Caribbean5.
A sessile protozoan (a folliculinid heterotrich ciliate,
Halofolliculina corallasia) that resides in a secreted black
sac-like test called a lorica is considered to be the cause of the
disease. Clusters of ciliates in lorica form a line between live
coral and dead coral giving a strong superficial resemblance to
Black Band Disease. However the empty lorica on the white coral
skeleton behind the dark band give a dotted appearance to the dead
zone and can be used to visually distinguish SEB from BBD26.
The disease progresses when the protozoan produces motile larvae
asexually. The larvae move ahead of the band onto the living coral
tissue, locate a site suitable to take up residence and proceed to
secrete a lorica of their own.
Damage to the coral’s skeleton and tissue death come about as a
result of a combination of chemicals associated with the
production of the new lorica and the physical drilling of the
lorica into the coral skeleton29.
On the GBR SEB has been observed to affect 31 species of corals
from 6 families with the majority of incidences recorded from
Acroporidae, Pocilloporidae, Poritidae and Favidae6.
The AIMS LTMP has only been monitoring SEB over the last two
years so little can be said on how the prevalence of the disease
is changing through time.
However the data set does allow a picture of the current spatial
distribution of the disease on the GBR. SCUBA search surveys in
2005 show that SEB is spread throughout the GBR.
Image 6. Close up view of skeletal eroding band disease on
Acropora sp. hard coral. From the centre the ciliates
have started to spread over all adjacent branches of the coral
simultaneously and the loricae are clearly visible.
from Winkler et al. 2004)
Click here for a larger view
It is most commonly found in the Cooktown/Lizard Island sector of
the GBR with another less intense area of activity with smaller
numbers of colonies affected in the Swain sector. Of the other reef
sectors surveyed SEB proved to be a relatively rare occurrence
(Graph 9). It is also apparent that SEB appears to be more common on
inner and midshelf reefs rather than outer shelf reefs
Mean (SE) number of colonies recorded as showing
signs of SEB per survey reef for each of the six LTMP survey
sectors in 2005. CL = Cooktown/Lizard Island, CA = Cairns, TO =
Townsville, WH = Whitsunday, SW = Swain, CB = Capricorn-Bunker.
Mean (SE) number of colonies recorded as
showing signs of SEB per shelf position in 2005.
Introduction | Black
Band Disease | White
Syndrome | Skeletal
Brown Band | Skeletal
tumours | Atramentous
Pinking | Vibrio
For further information contact
Ian Miller, AIMS
Telephone: +61 7 4753 4471
December 18, 2008