The effects of artificial reef vertical profile and hole diameter on fishes off South Carolina

Attraction of demersal finfish to six artificial reef designs off Charleston, South Carolina, was studied using a SCUBA visual census technique. The experiment was designed to examine the effect of (1) increased vertical profile and (2) hole diameter on the recruitment and retention of demersal finfish to each of the six artificial reef designs. Increased vertical profile was accomplished through the addition of fish aggregation devices (FADs) to half of the benthic artificial reef units, which were concurrently equipped with large diameter holes (25.4 cm diameter), small diameter holes (12.7 cm diameter), or no holes. Mean abundances of demersal finfish individuals were significantly greater on FAD units than on units lacking FADs. Hole diameter was only occasionally a significant factor affecting mean total number of demersal individuals and species and did not significantly affect estimated average total lengths of species present. Hole presence (both hole diameters) had a positive significant affect on mean numbers of demersal individuals and species. The dominant species observed on the reefs included Decapterus punctatus, Stenotomus chrysops, Centropristis striata, Monacanthus hispidus, and Haemulon aurolineatum. Early observations of the unit designs have already prompted the South Carolina Marine Artificial Reef Program to deploy artificial reef units of the same design in a permitted reef site.