Development of invertebrate assemblages on artificial reef cones off South Carolina: Comparison to an adjacent hard-bottom habitat

Abstract

Artificial reefs are often used to increase the amount of hard-bottom habitat in otherwise sandy areas, including parts of South Carolina's continental shelf. In 1997 and 2003, the SCDNR deployed two designed concrete reefs off the coast of Charleston, SC, for use in fishing experiments. This study was conducted to assess the development of epifaunal invertebrate assemblages on both the younger ("Area 53"—2 years old) and older ("Area 51"—8 years old) reefs. Each artificial reef was also compared to an adjacent natural reef, "Julian's Ledge", in an attempt to determine whether designed structures can form habitats that resemble natural hard-bottom areas over time.

Macrofaunal invertebrates from each of the three reef sites were collected during Spring/Summer 2005. A total of 24,940 individuals were found, comprising at least 384 motile and sessile species. Cluster analysis revealed that species composition between reef sites was distinct, with Julian's Ledge displaying higher species number and diversity; however, evidence for convergence over time included a large group of species common to all three sites, and a higher level of similarity between Julian's Ledge and Area 51 than between Julian's Ledge and Area 53. Additional sampling at a later time period could help to elucidate whether these trends may be attributed to reef age, or other environmental variables. This study provided the first catalogue of invertebrate data for any of South Carolina's designed experimental artificial reefs.