Effect of competition on dark spot syndrome in Stephanocoenia intersepta

Corals are frequently in competition with other benthic organisms, as space on the coral reef is highly sought after. With increased coral cover loss, and a possible coral-algal phase shift on reefs, competition between corals and other benthic organisms may become increasingly common. Competition between coral and other organisms, such as algae, other corals, and sponges may be a stressor for corals and possibly lead to increased disease prevalence and severity. Dark spot syndrome (DSS) is a highly prevalent disease in Bonaire and is found in the coral species Stephanocoenia intersepta and Siderastrea siderea. Some studies show that competition in corals increases their susceptibility to disease. This study investigates the correlation between coral competition and disease severity of dark spot syndrome in S. intersepta. One reason for this is that energy is allocated for competition rather than immune function and thus the coral’s ability to fight off disease is lowered. No significant correlation was found between the amount of competition (measured by the percent edge of the coral in competition) and the level of disease (measured by the percent of the coral with DSS). The mean disease level of all coral colonies is 2.56 (±0.34). There was also no correlation found between depth and severity of disease. Although no correlation was found, longer and more intensive studies are suggested to better understand the effect of competition on dark spot syndrome.

This student research was retrieved from Physis: Journal of Marine Science XIV (Fall 2013)19: 118-123 from CIEE Bonaire.