Fish associated with artificial reefs in False Bay, South Africa: a preliminary survey

Abstract

This study compares the suprabenthic fish assemblages inhabiting eight shipwrecks in False Bay with those found on adjacent natural reefs. 3411 fishes of 18 species were recorded on the wrecks. Species densities recorded on wrecks in both shallow and deep water (1.05 ± 0.07 and 1.01 ± 0.43 species/100 m²) were lower than those for natural reefs within the same depth zones (1.15 ± 0.21 to 1.81 ± 1.40 species/100 m²). In shallow water, reef teleost densities were lower on the wrecks (13.02 ± 2.56 fishes/100 m²) than on natural reefs (44.02 ± 28.72 to 58.42 ± 24.15 fishes/100 m²), while in deep water the difference was smaller (61.99 ± 51.61 fishes/100 m² compared to 40.57 ± 20.64 to 62.92 ± 20.77 fishes/100 m²). These results suggest that artificial reefs provide limited benefits to False Bay reef fishes and fisheries. In part this is due to their inappropriate location. Should future artificial reefs be deployed at more optimal sites, their benefits to reef fishes could be enhanced, without affecting their popularity as scuba dive sites.