Abstract

The inshore environment of Broward County, FL consists of three coral reef/hard bottom reef tracts, separated by sand substrate, running parallel to the coast in sequentially deepet water. At quarter nautical mile intervals, for a five mile coastline section, fishes were censused at western, eastern and crest sites of each of the three reef tracts. On SCUBA and using the Bohnsack/Bannerot point-count method, we recotded: fish abundance, species richness, size, and general habitat of an imaginary cylinder 15 m in diameter. The position of each site was recorded by DGPS after census. One hundred and eighty-one sites were censused duting a to month petiod (August 1998 to May 1999).\A total of 16,746 fish belonging to 139 species of 39 families were recorded. There were significant differences (p < 0.05, ANOVA) in the species tichness and the total abundance of fishes among the three reef tracts. There Were significantly fewer total fish (p < 0.001) and fewer fish species (p < 0.001) on the inshore reef tract as compared to either the middle or offshore reef tracts. The middle and offshore reefs tracts did not differ (p > 0.05, SNK). Diffetences were also found based on the location (edges or erest) on the reef. With all data from the three reef tracts combined, the eastern edge showed significantly fewer total fish (p < 0.001) than either the crest of the reef ot the western edge, which did not differ significantly (p> 0.05). Species richness also varied with the western edges of the tracts having significantly more species (p < 0.01) than the crests or the eastern edges, again there was no significant diffetence between these tWo (p > 0.05). Statistical analysis of a subjective complexity rating taken at each site mirrored the results of fish abundance and species richness. This supports the hypothesis that topographical complexity is, at least in part, a determinant in the differences in fish assemblages among the three reef tracts.

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