Methodology from Gambrel, B. and Lasker, H.R., 2016

While colony asymmetry was observed in many species, the planar form of G. ventalina was particularly conducive to quantifying colony size and asymmetry. The surface areas of both symmetric and asymmetric G. ventalina colonies were measured to evaluate the extent of asymmetry. We did not distinguish between intra- and inter-specific competitive interactions with asymmetric G. ventalina since our goal was to compare the sizes of asymmetric and symmetric colonies.

We sampled at Europa Bay, where similar numbers of symmetric and asymmetric G. ventalina colonies were found. We searched for G. ventalina within the same 500 m2 area as the belt transects, and we selected colonies based on their health (colonies overgrown with algae or hydrocorals were excluded from the study), size class (15−24 cm, 25−34 cm and 35−44 cm tall) and the presence or absence of asymmetry, since we wanted similar numbers of colonies in each category. A total of 142 G. ventalina colonies (78 symmetric and 64 asymmetric) were photographed. Each image included a 1 m2 quadrat and a ruler.