Seasonal sampling was carried out between spring 2005 and winter 2007, always choosing days with calm sea conditions. Sampling units (10 m * 1 m each, separated by ≥15 m) located along three replicated transects (five sampling units per one of the three transects analyzed in each of the four seasons) were assessed. Within sampling units one scientific SCUBA diver (always the same) recorded the water depth and frequency of habitat type.