PROJECT AND FINDINGS:
Six vessel-reefs off the coast of southeast Florida were censused quarterly (two ships per month) to characterize the
associated fish assemblages. SCUBA divers used a non-destructive point-count method to visually assess the fish assemblages
over 13- and 12-month intervals (March 2000 to March 2001 and March 2002 to February 2003). During the same intervals, fish
assemblages at neighboring natural reefs were also censused. A total of 114,448 fishes of 193 species was counted on natural
and vessel-reefs combined. Fish abundance and species richness were significantly higher on vessel-reefs in comparison to
natural reef. Haemulidae (grunts), the most abundant family on vessel-reefs, represented 46% of total abundance.
On natural reefs, wrasses were the most abundant family, accounting for 24% of total abundance. The number of species also
differed among vessel-reefs, with the most recently deployed having fewer species than the earliest deployed. Fish assemblage
structure on natural versus artificial reefs exhibited a low similarity (27%). Interestingly, the juvenile phase of two
deep-water, economically important species was repeatedly recorded on vessel-reefs, but has never been observed on natural
reef in our study area. This may be an indication that vessel-reefs are supplying ancillary nursery/juvenile habitat for these
animals that may be unavailable or limited on surrounding natural reef. Further, a comparison of natural reef sites
immediately adjacent to the vessels with those more distant, does not support a simple aggregation hypothesis.
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