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Journal of Marine Biology
Volume 2011, Article ID 490198, 8 pages
Research Article

Coral Diversity and the Severity of Disease Outbreaks: A Cross-Regional Comparison of Acropora White Syndrome in a Species-Rich Region (American Samoa) with a Species-Poor Region (Northwestern Hawaiian Islands)

1Hawaii Institute of Marine Biology, Kaneohe, HI 96744, USA
2Australian Institute of Marine Science, PMB 3, Townsville, QLD 4810, Australia
3US Geological Survey, National Wildlife Health Center, Honolulu Field Station, Honolulu, HI 96850, USA

Received 16 July 2010; Accepted 27 November 2010

Academic Editor: Judith D. Lemus

Copyright © 2011 G. S. Aeby et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The dynamics of the coral disease, Acropora white syndrome (AWS), was directly compared on reefs in the species-poor region of the Northwestern Hawaiian Islands (NWHI) and the species-rich region of American Samoa (AS) with results suggesting that biodiversity, which can affect the abundance of susceptible hosts, is important in influencing the impacts of coral disease outbreaks. The diversity-disease hypothesis predicts that decreased host species diversity should result in increased disease severity of specialist pathogens. We found that AWS was more prevalent and had a higher incidence within the NWHI as compared to AS. Individual Acropora colonies affected by AWS showed high mortality in both regions, but case fatality rate and disease severity was higher in the NWHI. The site within the NWHI had a monospecific stand of A. cytherea; a species that is highly susceptible to AWS. Once AWS entered the site, it spread easily amongst the abundant susceptible hosts. The site within AS contained numerous Acropora species, which differed in their apparent susceptibility to infection and disease severity, which in turn reduced disease spread. Manipulative studies showed AWS was transmissible through direct contact in three Acropora species. These results will help managers predict and respond to disease outbreaks.