Drupella, Thiele, 1925

Scott, C. M., Mehrotra, R., Hein, M. Y., Moerland, M. S. & Hoeksema, B. W., 2017, Population dynamics of corallivores (Drupella and Acanthaster) on coral reefs of Koh Tao, a diving destination in the Gulf of Thailand, Raffles Bulletin of Zoology 65, pp. 68-79 : 70

Drupella and Acanthaster abundance relative to reef threats. Abundances of Drupella and Acanthaster individuals were then plotted against published descriptions of diving pressure, level of use, and degree of reef protection on Koh Tao ( Weterings, 2011; Lamb et al., 2014; Hein et al., 2015). The study by Weterings (2011) used dive school questionnaires to quantify the number of dives being conducted at any single site and used weighted equations to create a relative scale of dive site use, with the maximum value (i.e., most dived site) set to 20. The values for dive site pressure were plotted against both Drupella and Acanthaster abundances at sites that overlapped with EMP monitoring, and linear regression analyses were performed to investigate the significance of these relationships. A study by Lamb et al. (2014) used the data by Weterings (2011) and local knowledge of reef sites to identify five ‘high-use’ and five ‘low-use’ sites around the island. They looked at 10,499 coral colonies at those sites to identify the percent of corals as ‘Healthy’, ‘Diseased’, ‘Compromised Health’, or ‘Physically Damaged,’ in order to assess the impact of diving on these reef areas. The total percent of corals coded as non-healthy between both high- and low-use sites overlapping with this study was plotted against both Drupella and Acanthaster abundances. Again, linear regression analyses were performed to test the significance of the relationships between coral health categories and Drupella and Acanthaster abundances, respectively. A 1-way analysis of variance was also used to compare differences in abundances between both taxa found in overlapping high-use and low-use sites respectively. Finally, the study by Hein et al. (2015) categorised sites based on their protection through the local zoning and coastal regulations implemented in 2012 ( Platong, 2012). Abundances of Drupella and Acanthaster were plotted against overlapping sites in MPA and non-MPA respectively and 1-way analyses of variances were used to determine the significance of these relationships.