Collection and experimental setup methods extracted from Doo et al. (2018):
Colony collection: In January 2017, 48 colonies of Pocillopora verrucosa (Ellis and Solander 1786) were collected randomly on scuba from 5 m depth on the north shore of Mo’orea, French Polynesia (17° 28' 33"S, 149° 49' 20"W). Following 5 d of acclimation, 24 of the corals were selected randomly for removal of all trapeziid crabs and alpheid shrimps ("minus-ectosymbiont") by probing with a wooden stick (3 mm diameter). Crabs and shrimp were left in the other 24 corals ("plus-ectosymbiont"), which were subjected to a procedural control in which they were probed with a wooden stick.

Incubation setup: Twelve mesocosm tanks (150 L volume with sand-filtered seawater pumped from 14 m depth in Cooks’ Bay and supplied to the tanks at ~200 mL min−1) were used in this experiment, with four colonies per tank in a split-plot design contrasting plus-ectosymbiont (n = 2 colonies/tank) and minus-ectosymbiont (n = 2 colonies/tank) corals.

Daily measures of salinity, pH, and total alkalinity (TA): 
Temperature was recorded with a thermometer (± 0.05 degrees C; ThermoFisher Traceable) and salinity was measured with a bench-top conductivity meter (± 0.1 psu, YSI 3100). TA and pH were measured within one hour of sample collection. Seawater collected for TA was filtered (0.45 um; Chanson and Millero, 2007) and analyzed using potentiometric titrations with 0.1-N HCl using an automatic titrator (Mettler Toledo T50) (Dickson et al., 2007). Seawater pH was measured with spectrophotometric methods (Nemzer and Dickson, 2005).

Buoyant weight: was measured at start and end of experiment and difference between the two values was used to calculate an increase in dry skeletal weight (i.e., calcification) using the density of aragonite, and then normalized to the surface area of each coral (Davies 1989).