Effects of Refuge Size and Complexity on Recruitment and Fish Assemblage Formation on Small Artificial Reefs

There have been a number of natural and artificial reef studies examining possible correlation's between refuge size and complexity and the associated fish assemblages. Results of these studies have been contradictory indicating possible site dependent differences. We examined the role of refuge size and complexity in fish recroitment and the formation of associated fish assemblages, using artificial reef modules, at two different depths off Fort Lauderdale, Florida, USA. The 1 m3 reef modules (Swiss Cheese reefs) were constructed of poured concrete with 12 tunnels running through the block. six tunnels in each direction perpendicular to each other. Twenty replicates were constructed of each of three different refuge configurations, 12 large tunnels (square opening, 15 cm per side), 12 small tunnels (7.5 cm per side) or six large and six small tunnels. Ten replicates of each reef design were deployed at each depth (7 m and 20 m) on sandy substrate. Significant differences were found for recroits (fishes O - 5 cm TL), total fish abundance, and species richness between refuge configurations as well as depths. Additionally, this study was designed, in part, to replicate work done previously by others, in the Caribbean examining the effects of refuge size on fish abundance and species richness. Differences were found between the studies. This may be due, in part, to differences in local fish species composition and population structure.