The effects of Stegastes planifrons gardening on the prevalence of yellow band disease in the Montastrea annularis species complex
Yellow band disease (YBD) is a bacterial infection affecting corals of the Montastrea annularis species complex. Recent mortality rates of M. annularis spp. on Bonaire have risen due to YBD and other biotic and abiotic factors. The loss of staghorn coral, Acropora cervicornis, the preferred habitat of the threespot damselfish, Stegastes planifrons, has caused the damselfish to inhabit M. annularis spp. Unfortunately, M. annularis spp. are slower growing corals that take longer to reach reproductive maturity and are thus less able to withstand S. planifrons biting their tissues and creating algal gardens on exposed skeleton. This weakens the coral and makes it more susceptible to diseases like YBD. The objective of this study was to examine the relationship between S. planifrons gardening and YBD. Sample sites of healthy and diseased colonies of M. annularis spp. were established across depths at Yellow Sub dive site in Kralendijk, Bonaire. Sites were monitored for damselfish inhabitants and signs of coral biting. Pictures were taken of each site to chart the progress of the disease over the course of the study, and ImageJ was used to determine percent cover of healthy versus unhealthy coral. No significant relationship was found between S. planifrons activity and YBD, although S. planifrons seemed to select healthy colonies. The increase of damselfish populations and their detrimental effects on Bonaire’s reef calls attention to the need for fishing regulations of predatory species and a heavier focus on the conservation of A. cervicornis thickets.