DEVELOPMENT OF FISH ASSEMBLAGES AT ARTIFICIAL REEFS IN SINGAPORE AND ITS EFFECT ON A NEARBY PATCH REEF

Abstract

Two small artificial reefs of concrete blocks and tyre modules were established on the seafloor, 20-30m away from a patch reef, Terumbu Pempang Tengah (TPT), in Sep'89. Visual monitoring revealed that both species richness and fish abundance increased at the artificial reef sites from 1991-94. Average species richness per census at the artificial reefs was comparable to the 10m depth of TPT. Fish density but not fish abundance was higher at the artificial reefs than TPT. Fish fauna at the artificial reefs was similar to TPT. The concrete blocks appeared to be a better artificial reef structure. Although species richness per census was similar at both types of artificial reef, fish abundance and densities were higher at the concrete reef. The concrete reef also attracted greater numbers of economically important fishes. Larger-sized fishes were more common at the concrete reef, while smaller-sized fishes and juveniles were more abundant at the tyre reef. The presence of the artificial reefs did not decrease species richness or fish abundance at the adjacent patch reef. Results of this study show that artificial reefs can enhance fish populations in the vicinity, without diminishing those on nearby reefs. Artificial reefs placed in close proximity to natural reef areas could function as an extension of the natural habitat.