Fish growth, reproduction, and tissue production on artificial reefs relative to natural reefs

The extent towhich artificial reefsmaybe useful formitigation of environmental impacts, fisheriesmanagement, and conservation depends in part upon how well the organisms that live on them fare. We tested whether fish living on artificial reefs were in similar condition (weight-at-length), grew, foraged, reproduced, and produced tissue at rates similar to those on natural reefs. We studied five artificial–natural reef pairs spread over .200 km in the Southern California Bight. Underwater visual transects were used to quantify density and size structure of four target species (Paralabrax clathratus, Paralabrax nebulifer, Semicossyphus pulcher, and Embiotoca jacksoni), which were also collected to measure foraging success, condition, growth, reproductive output, and tissue production. Generally, fish living on artificial reefs fared as well or better than those on natural reefs, with some exceptions. Semicossyphus pulcher fared better on artificial reefs, having higher foraging success, fecundity, densities, and tissue production. Embiotoca jacksoni grew faster on natural reefs, and P. nebulifer was in slightly better condition on natural reefs. Total fish tissueproduction tended tobehigheron artificial reefs thanonnatural reefs, though this patternwasnot evidenton all reef pairs. Tissueproduction was positively correlated with the abundance of large boulders, which was higher on artificial reefs than natural reefs. The similar or greater production of fish tissue per cubic metre on artificial reefs relative to natural reefs indicates that these artificial habitats are valuable in producing fish biomass. Fish living on artificial reefs fared as well as those living on natural reefs, indicating that well-designed artificial reefs can be useful tools for mitigation, conservation, and fisheries management.