The data presented in this file have been published in: Tsounis, G., Steele, M. A., & Edmunds, P. J. Elevated feeding rates of fishes within octocoral canopies on Caribbean reefs.Coral Reefs (2020) 39:1299-1311, doi: 10.1007/s00338-020-01963-1.

Surveys were conducted at octocoral communities in St John, US Virgin Islands, in February and March 2016. Building on our previous studies on the environmental impact of octocoral community structure (Tsounis and Edmunds 2017; Tsounis et al. 2018), the present study was conducted at East Cabritte, Europa Bay, and East Tektite, within the Virgin Islands National Park, along the south shore of St. John.

Hypothesis (3) was tested: the role of competition in algal turf and macroalgae in determining the success of octocoral and scleractian recruits.

Methods: A “focal individual” sampling technique was used to quantify the bite rate of individual herbivorous fishes as a function of proximity to octocoral colonies. In this approach, the behavior of a haphazardly selected focal fish (belonging to one of two important and abundant groups, surgeonfishes and parrotfishes) was recorded until either it was lost from view or the observation period ended (5 min duration). During the observation period, the number of bites on benthic surfaces by the focal fish was counted and summed by location relative to the nearest octocoral colony of at least average size at each site (> 19.5 cm at Europa Bay and East Tektite; > 31.8 cm at East Cabritte, hereafter referred to as “large” colonies). Sizes of colonies were estimated by eye. Proximity to the nearest octocoral colony was categorically distinguished as “close” or “far” based on distances estimated by eye to the nearest 0.1 m, with these categories determined by the average colony height for the site (i.e., close was within ~20 cm at Europa Bay and East Tektite; and ~32 cm at East Cabritte). Consequently distances between fish and large octocorals were considered far if they were > 20 cm at Europa Bay and East Tektite; and > 32 cm at East Cabritte.

To compare demersal fish feeding behavior within octocoral communities versus at the edges of these communities, locations within ("in canopy") octocoral communities were defined as > 5 m from the edge ("edge").