On 02 October 2008, ten pairs of small focal patch reefs (2–6 square meters in area) were selected that were predominately (80 %) live Porites lobata and separated from nearest neighbouring reefs by at least 0.5 m of sand. One member of each pair of reefs lacked populations of adult C.maximum; the other member of the pair had C.maximum adults present. Although these were not quantified, densities appeared approximately similar to densities on P. lobata reefs reported elsewhere (e.g., Shima et al. 2010). These reefs also had corresponding morphological differences: i.e., reefs without vermetids were rounded, and those with vermetids were flattened (see Shima et al. 2010).
On the same reefs, and over the same time period, two haphazardly positioned 15 x 15 cm quadrats (each with 100 % live coral cover) were marked on each reef by embedding a cable tie into marine epoxy in each of the four corners. One quadrat on each reef was left with 100 % coral cover (called ‘unmanipulated’). In the other, 50 % of the live coral (evenly distributed through the quadrat) was chipped and scraped away with a geology hammer to mimic disturbance to live coral (e.g., due to fish grazing or anchor chains); we refer to these as ‘scarred’ quadrats. Each quadrat was photographed. Six months later (April 2009), quadrats were photographed again, the vermetids were counted and identified, and the substrate they were on (e.g., live coral, non-living substrate - bare/dead patch, marine epoxy).