Abstract

The importance of near-shore reefs in providing habitat for adult and juvenile fishes and macro-invertebrates has been well established, but the differences between natural and artificial reefs in providing this habitat function is poorly understood. The overall objective of this study was to determine seasonal fish and macro-invertebrate assemblage differences between shallow (6-12 m deep), near-shore natural and artificial reefs in an effort to gain insight into how the functions of these reef types differ. This report describes preliminary data on the seasonal distribution and abundance of fishes among 3 reef types (high-relief natural (>0.5 m), low-relief natural (< 0.5 m), and artificial reefs) in four blocks, in addition to the living and structural habitat characteristics of those sites. The location of the study was off the eastern end of St. George Sound, Florida (SW of Florida State University Coastal and Marine Laboratory (FSUCML)) just offshore of extensive seagrass habitat. Around each reef site a 1-km x 1-km area was mapped with sidescan sonar which provided the exact positions of habitat structures within the sites. Five sampling stations were randomly selected within each of the three reef types in each zone (= 15 sampling stations within each zone). Stations were surveyed seasonally using the point-count method of Bohnsack-Bannerot (1989) plus drop cameras to assess fish diversity and abundance. Sessile macro-invertebrates, also surveyed seasonally, were quantified from quadrat photos taken along three randomly chosen 30-m transects in each of the three habitat types of each zone. Preliminary results suggest differences in fish communities between natural and artificial reefs as well as among different types of artificial and natural reef structures. The temporal relationships between habitat type and community composition are complex, but we expect that our approach to this problem will reveal community patterns and lead to hypotheses on the processes driving those patterns

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