Food organism production on artificial reefs: roles of sedentary fauna for spatial heterogeneity

Abstract

Secondary production on two types of artificial reefs are compared from the aspects of the roles of sedentary epifauna to increase spatial heterogeneity. Food organisms for reef fish were more abundant on a steel reef made of reinforcing rods than on a concrete reef with flat surfaces. On the steel reef, deposit feeding Polychaeta increased as Ascidiacea and Bryozoa densities increased. Maxillpoda and Demospongeae were abundant on the concrete reef while they could not grow on the iron rods of the steel reef. Although their role to offer habitats for small mobile epifauna is important on the concrete reef with flat surface, they kept the faunal community on the concrete reef in an early stage of succession and thus made the secondary production lower than the steel reef. Artificial reef design should consider the attachment of primary inhabitants in terms of community maturing process, too.