Spatial and temporal patterns of coral black band disease (BBD) prevalence were examined during the summers of 2004 to 2008 at 10 reef sites located along a sewage gradient on either side of a major marine outfall on Bermuda's south shore. The gradient was identified by current meter and drogue deployments and confirmed by a water quality monitoring using fecal indicator bacteria (gastrointestinal enterococci) as a sewage marker. BBD prevalence was also examined at 22 locations across the Bermuda platform in different physiographic reef zones, identified by reef survey techniques and analysis of community composition. BBD prevalence was generally low and was recorded in Diploria strigosa > Montastraea franksi > M. cavernosa = D. labyrinthiformis > Porites astreoides and the hydrocoral Millepora alcicornis. Most occurrences were in D. strigosa, and BBD prevalence was highest on the outer rim reef (range: 0.3 to 1.9%), followed by the outer lagoonal patch reefs (range: 0.05 to 0.8%) and the deeper terrace reefs (range: 0.1 to 0.2%). BBD prevalence levels decreased over the study period, and BBD was only rarely observed in D. labyrinthiformis, which appears to be immune to infection in Bermuda. The BBD prevalence in D. strigosa was lower on reefs regularly exposed to sewage than on the near pristine outer rim reef sites, which experience the exceptional water quality characteristics of the oligotrophic North Atlantic gyre.
KEY WORDS: Coral · Black band disease · Sewage · Bermuda
Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 462: 79-92, 2012 80 most widespread diseases in the Carib bean and adjacent waters (Antonius 1981, Weil 2004, primarily infecting massive framework building scleractinian corals, including Diploria spp., Montastraea spp., Colpophyllia natans and Siderastrea siderea (Antonius 1981, Edmunds 1991, Sutherland et al. 2004). The disease is now recognized as having a global distribution (Sutherland et al. 2004).A number of field studies have suggested a link between sewage pollution and BBD outbreaks. Taylor (1983) reported an association between BBD prevalence and sewage pollution or poor water quality, but the study does not show any data, and reference is made to other still unpublished work by the same author suggesting the association. Antonius (1985) purports to show a link between disease frequency and sewage pollution, but again, the evidence is based upon a perceptible increase in BBD frequency near a sewage outfall; no data are shown. Kaczmarsky et al. (2005) recorded a significantly higher prevalence of BBD and White Plague type II in corals at a single location compared to a single control site 2.5 km away. The site where the disease prevalence was higher was occasionally exposed to un-treated sewage (during emergency sewage bypass events). Kuta & Richardson (2002) found a positive relationship between elevated nitrite and BBD prevalence in Florida but did not find an overall positive correlation with the more readily assimilab...