The Epizootiology of Coral Diseases in South Florida Research and Development EPA/600/R-05/146 May 2006 The Epizootiology of Coral Diseases in South Florida by Deborah L. Santavy1, Jed Campbell1, Robert L. Quarles1, James M. Patrick1, Linda M. Harwell1, Mel Parsons2 , Lauri MacLaughlin3 , John Halas3, Erich Mueller4, 5, Esther C. Peters4, 6, Jane Hawkridge4, 7 1United States Environmental Protection Agency National Health and Environmental Effects Research Laboratory Gulf Ecology Division 1 Sabine Island Drive Gulf Breeze, FL 32561 2United States Environmental Protection Agency, Region 4 Science and Ecosystems Support Division 980 College Station Road Athens, GA 30605 3NOAA, Florida Keys National Marine Sanctuary Upper Region, MM 95 Overseas Highway Key Largo, FL 33037 4Mote Marine Laboratory Center for Tropical Research 24244 Overseas Highway (US 1) Summerland Key, FL 33042 5Perry Institute for Marine Science 100 N. U.S. Highway 1, Suite 202 Jupiter, FL 33477 6Tetra Tech, Inc. 10306 Eaton Place, Suite 340 Fairfax, VA 22030 7Joint Nature Conservation Committee, Monkstone House, City Road Peterborough, United Kingdom PE1 1JY Notice The U.S. Environmental Protection Agency (U.S. EPA), Office of Research and Development (ORD), National Health and Environmental Effect Research Laboratory (NHEERL), Gulf Ecology Division (GED), the U.S. Department of Commerce (U.S. DOC) National Oceanographic and Atmospheric Association (NOAA) National Marine Sanctuary Program Florida Keys National Marine Sanctuary (FKNMS), and the U.S. Department of Interior (DOI) National Park Service (NPS) Dry Tortugas National Park (DTNP) jointly conducted this program. The report has undergone U.S. EPA’s peer and administrative reviews and has received approval for publication as a U.S. EPA document. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. The recommendations expressed in this publication are solely those of the authors and do not necessarily reflect those of the sponsoring agencies. The appropriate citation for this report is: Santavy, D.L., J. Campbell, R.L. Quarles, J.M. Patrick, L.M. Harwell, M. Parsons, L. MacLaughlin, J. Halas, E. Mueller, E.C. Peters and J. Hawkridge. 2006. The Epizootiology of Coral Diseases in South Florida. EPA/ 600/R-05/146. U.S. Environmental Protection Agency, Gulf Ecology Division, Gulf Breeze, Florida. ii Abstract The mortality of reef-building corals has increased at unprecedented rates during the past three decades. It is widely accepted among the scientific community that pristine reefs no longer exist anywhere on earth. Some scientists are forewarning of ecological extinction for region-wide coral reefs within this century if current trends persist. This report summarizes the condition of South Florida reefs by providing an overview of historical studies published in the scientific literature and a synopsis of collaborative field investigations by EPA, NOAA and Mote Marine Laboratory. The study’s objectives were to establish the current status of coral health and disease and detect changes over time. Four epizootiological surveys were conducted: (1) spring 1998, (2) summer 1998, (3) spring 1999, and (4) August 2000. We surveyed sites in the Upper, Middle and Lower Florida Keys, the New Grounds of the Florida Keys National Marine Sanctuary, Biscayne National Park, and Dry Tortugas National Park. All surveys were conducted using a radial arc transect method developed for the coral disease assessment. Only the 2m-wide segment, 8-10m from the center of the radial arc transect, was surveyed at each site (area surveyed = 113m2). Twenty-two species of scleractinian corals and gorgonian sea fans were inspected for 11 coral diseases described in the literature, plus two additional syndromes. A probabilistic survey design in August 2000 generated areal estimates of the extent and intensity of coral disease in South Florida. At least one coral colony was affected by active disease at any single location in 85 ± 9% (95% confidence interval) of the area sampled; 15 ± 9% (662 ha) of the area sampled contained no coral disease. Coral disease was widely dispersed throughout South Florida reefs and was not confined to a particular region. Although disease was widespread, maximum disease prevalence at a site was 13%, representing 2.2 ± 4% (97 ha) of the sampling area. This study established a baseline so that future probabilistic surveys can examine changes and trends in coral condition. Annual disease prevalence from 1998 through 2000 ranged from 0 to 43% among all the sites surveyed. No hot spots were found where a high level of disease was sustained at the same site for multiple survey periods. The highest disease prevalence was observed at Looe Key (LK03) back reef site in summer 1998, where 42.9% of the colonies were diseased, with white pox affecting 41.4% of the monitored species. White pox and aspergillosis were the most abundant diseases observed at sites, where greater than 20% of the colonies were diseased. The dominant diseases found among all the sites were white pox, aspergillosis, dark spots disease, white-band disease, and white plague. Species with significant declines over the course of the study were Acropora palmata, Acropora cervicornis, Montastraea annularis complex, and Colpophyllia natans. This report compares spatial and temporal distribution of species composition and disease prevalence among regions, reef types, and between survey periods. The highest level of disease prevalence was recorded in 1998 and 1999, with lower or no disease prevalence observed in subsequent years. Overall, the greatest destruction of coral colonies occurred during the summer of 1998, when a period of high disease prevalence, massive bleaching, and a powerful hurricane passed over this area causing great destruction of the reefs. Non-parametric multivariate analyses did not reveal any logical spatial correlations between disease distribution and geographical regions, reef type, or water depth. Future research will evaluate geospatial relationships between stressors, including water quality, and trends in coral health on the Florida reef tract. iii iv Contents Abstract ........................................................................................................................................... iii Figures ............................................................................................................................................. vi Tables .............................................................................................................................................. vii Site Names and Codes .................................................................................................................... viii Acronyms and Abbreviations ............................................................................................................ ix Acknowledgements .......................................................................................................................... x Introduction ...................................................................................................................................... 1 Documented Declines in Coral Coverage.................................................................................... 1 Diseases of Reef-Building Corals...................................................................................................... 3 Distribution and Frequency of Coral Diseases ............................................................................ 4 Epizootiological Assessment of Coral Disease ................................................................................. 5 Background ............................................................................................................................... 5 Approach ................................................................................................................................... 5 Sampling Selection ................................................................................................................ 7 Survey Methodology ............................................................................................................... 7 Statistical Analysis ................................................................................................................. 9 Results and Discussion ................................................................................................................... 10 Species Composition and Disease Prevalence ........................................................................... 11 Principal Component Analysis ................................................................................................... 14 Spatial Distribution of Diseases ................................................................................................. 16 Conclusions ..................................................................................................................................... 16 References ....................................................................................................................................... 17 Appendices A. All sites sampled during surveys, including regions, site names, codes, latitude and longitudes, and depths .............................................................................. A-1 B. Coral diseases sampled for the study during the 1998-2000 surveys............................. B-1 C.