Development of benthic and fish assemblages on artificial reef materials compared to adjacent natural reef assemblages in Miami-Dade County, Florida

The Bal Harbour Artificial Reef was constructed with 176 prefabricated modules and 8000 t of limerock boulders as mitigation for natural reef impacts sustained during a beach renourishment project. A long-term monitoring program was developed and initiated in 1999 to evaluate the effectiveness of these artificial reef materials as mitigation for natural reef impacts. Benthic and fish assemblages on the modules, boulders, and two adjacent natural reefs were monitored and compared. The natural reef areas showed stable fish and benthic populations with consistent levels of similarity and abundance throughout the period of comparison. During the first 4 yrs, the benthic assemblages on the artificial reefs changed significantly, with increasing density and diversity, and increasing similarity to the natural reef areas. After 5 yrs, the density and diversity of the benthic assemblages on the artificial reef materials appear to be stabilizing. In contrast, fish assemblages differed significantly between the two different artificial reef materials as well as between the artificial and natural reefs. Differences in the physical characteristics between artificial and natural reef materials (i.e., shape, relief, cryptic space, etc.) have and will continue to affect the extent to which the reefs can become similar.