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Information about Coral Disease
Coral disease was first recognized as a threat to Caribbean reefs in 1972 when Antonius
(Antonius, 1973) reported the discovery of black band disease. Since that time the
prevalence and incidence of coral disease has been reported in an ever-increasing
frequency. The most comprehensive record of coral disease resides in the WCMC Global Disease Database.
Although coral reefs have been severely impacted in the Caribbean by disease over
the past few decades, the Pacific reefs were considered relatively unaffected. Recently
a workshop held in Hawaii, Coral Health and Disease in the Pacific: Vision for
Action (Galloway et al., 2009) synthesized the state of knowledge of
Pacific coral diseases and set a Strategic Research Plan for that region.
What is Coral Disease?
Disease is any deviation from, or interruption of, the normal structure or function
of any body part, organ, or system that is manifested by a characteristic set of
signs and whose etiology, pathology, and prognosis may be known or unknown (Dorland,
2006). Coral disease is often manifested as either color change or skeletal damage
and may be accompanied by tissue loss.
Coral Disease Nomenclature
The nomenclature for coral disease has evolved from field descriptions of gross visible
signs of change from the ‘normal’ appearance of the coral
holobiont. The Coral Disease and Health Consortium (CDHC) has attempted
to standardize the nomenclature (Galloway et al., 2007) used to describe specific
field conditions and further to differentiate between a
field diagnosis, a morphologic diagnosis
and an etiologic diagnosis during
several workshops. The terminology used in this webpage reflects the consensus opinion
of the coral research community and is taken from two recent field guides to the
identification of coral disease in the field (Bruckner, 2009; Weil and Hooten, 2010)
Biotic Diseases of the Western Atlantic
Non-Biotic Diseases Of The Western Atlantic
Diseases, that are described in detail in the peer-reviewed literature or at formal
workshops, are defined by agreed upon characteristics that descibe their field and
morphologic diagnoses using standard terminology. The final step of confirming a
disease state involves collecting sufficient information that may include performing
a test of Koch’s postulates, identifying the causative agent or identifying a significant
compendium of evidence indicating the presumed disease state.
Many coral diseases have not been characterized under peer-reviewed venues. At the
present time much confusion and disagreement exists about these diseases within
the non-peer reviewed literature. Contradictory descriptions are found on various
disease identification cards and web sites (for example, the same name of “red band
disease” has been given to five very different observations of cyanobacteria on
corals). To ensure high quality presentation of coral disease knowledge, we have
chosen a path no less than that of coral disease journals; namely, to focus only
on disease characterizations supported by documented (peer-reviewed) data.
The Environment and Coral Disease
One of the most important, yet least understood, aspects of coral disease is the
relationship between disease incidence and the environment. While it has been suggested
that the recent increase in coral diseases is associated with a decline in reef
environmental quality, very little quantitative work has been carried out in this
area. We now know that five coral diseases are positively correlated with high water
temperature – these are bacterial bleaching, black band disease, plague, aspergillosis
and dark spots disease.
Nutrient (sewage) input, sedimentation, and runoff have
all been cited as correlated with disease incidence, however in almost all of these
reports no data are provided. Only two quantitative studies to date have revealed
statistical relationships between water quality factors and disease prevalence.
Kim and Harvell (2002) demonstrated positive correlations between the prevalence
of aspergillosis and both elevated dissolved inorganic nitrogen and slightly lower
water clarity. Kuta and Richardson (2002) found that black band disease incidence
was correlated with elevated concentrations of nitrite (and lower concentrations
of soluble reactive phosphate). This research area is critical.
Antonius A. (1973) New observations on coral destruction in reefs, Abstract, Tenth
Meeting of the Association of Island Marine Laboratories of the Caribbean, University
of Puerto Rico, Mayaguez, PR. pp. 3-3.
Bruckner A.W. (2009) Field Guide to Western Atlantic Coral Diseases, USDC National
Oceanic and Atmospheric Administration, Silver Spring, MD.
Dorland W.A.N. (2006) Dorland's Illustrated Medical Dictionary, Saunders, W.B. .
Galloway S., Work T., Bochsler V., Harley R., Kramarsky-Winters E., Mc Laughlin S.,
Meteyer C., Morado J., Nicholson J., Parnell P., Peters E., Reynolds T., Rotstein
D., Sileo L., Woodley C. (2007) CDHC Workshop: Coral Histopathology II, NOAA Technical
Memorandum NOS NCCOS 56 and CRCP 4, National Oceanic and Atmospheric Administration,
Silver Spring, MD. pp. 83.
Galloway S.B., Bruckner A.W., Woodley C.M. (2009) Coral Health andDisease in the
Pacific: Vision for Action NOAA Technical Memorandum NOS NCCOS 97 and CRCP 7, National
Oceanic and Atmospheric Administration, Silver Spring, MD. pp. 314.
Kim K., Harvell C.D. (2002) Aspergillosis of sea fan corals: disease dynamics in
the Florida Keys, in: J. W. Porter and K. G. Porter (Eds.), The Everglades, Florida
Bay, and coral reefs of the Florida Keys: an ecosystem sourcebook., CRC Press, Boca
Raton, London. pp. 813-824.
Kuta K.G., Richardson L.L. (2002) Ecological aspects of black band disease of corals:
relationships between disease incidence and environmental factors. Coral Reefs 21:393-398.
Weil E., Hooten A.J. (2010) Underwater Cards for Assessing Coral Health on Caribbean
Reefs, in: GEF, et al. (Eds.).