Disease resistance in the threatened staghorn coral, Acropora cervicornis

Guy Harvey Oceanographic Center Facility

The staghorn coral, Acropora cervicornis, is a major reef-building scleractinian coral found throughout Florida and the Caribbean that experienced unprecedented population declines starting in the 1970s. The declines are attributed primarily to coral bleaching, white-band disease (WBD), and other tissue loss syndromes. Previous research indicates that disease-resistant genotypes exist based on research conducted in Panama. It is unknown if disease resistant genotypes exist in Florida Keys populations. We tested the potential for rapid tissue loss (RTL) resistance among 48 A. cervicornis genotypes maintained in a Florida Keys nursery by grafting active disease fragments to apparently healthy fragments. Tissue degradation was documented visually by the presence or absence of RTL (denoted by a characteristic margin where the zooxanthellate tissue is denuded from the skeleton), followed by histological analysis to further characterize potential tissue degradation. In the preliminary disease screening, 7 out of 48 genotypes showed signs of rapid tissue loss transmission after five days. Only two control fragments showed signs of disease transmission. Histological analysis revealed that transmission of RTL was significantly (p0.05) on RTL transmission (presence/absence) or time to transmission. These results provide relevant information to help improve the efficacy of future management strategies of Acropora populations, as well as better understand how this species and other scleractinian corals will respond to changing climate conditions.