Date of Award

Spring 2006

Document Type

Legacy Thesis

Degree Name

Master of Science in Coastal Marine and Wetland Studies

Department

Coastal and Marine Systems Science

College

College of Science

First Advisor

Keith R. Walters

Second Advisor

Daniel C. Abel

Third Advisor

Robert F. Young

Additional Advisors

Dennis M. Allen

Abstract

Artificial reefs specifically constructed to attract fishes to areas that previously were devoid of structural habitat have been successful in increasing species abundance and diversity. Recent offshore projects managed by the South Carolina Department of Natural Resources have been expanded into inshore waters and in March 2004, two artificial reefs were constructed in Winyah Bay, a northeastern South Carolina estuary. Differences in nekton and macroepifaunal community associated with inshore reefs were evaluated at one of the reef sites; approximately 110 m in diameter and a non-reef site, without structural habitat. Habitat trays containing oyster shells were deployed in an effort to quantify both the effects of the artificial reef and smaller vertical structure on the associated community. Replicate trays (1 m2) were sampled on a weekly basis from June to September 2005. Habitat tray treatment levels included an empty tray, oyster shells arranged flat and oyster shells arranged into a vertical structure. Reef and non-reef sites did not exhibit any differences in total abundance of fishes and macroinvertebrates, but abundances did tend to be greater on the non-reef site. Comparison of the habitat treatment levels indicated that the presence of structure, especially vertical structure can significantly increase community abundances of small demersal fishes and macro invertebrates but not species richness. One of the reasons organisms are attracted to more complex habitats is likely related to both refuge and predation. Potential effects of predation by reef associated fishes may account for the lower abundances at the reef site. However, the absence of any visible reef structure on the reef site may suggest that the reef structures may have buried via sedimentation. In an effort to identify a rationale for the differences in taxa richness found at the non-reef site, a separate experiment was conducted from October to November 2005 to assess the possibility of tidal influence on the non-reef site. Data indicated that sampling at low tide could have potentially influenced the composition of fishes and macro invertebrates found at the non-reef site. In light of the results from this study, we concluded that although habitat complexity may be an important factor affecting the structure of an estuarine fish and macroinvertebrate community, the placement of reef macrostructure within an estuarine system may require substantial forethought to insure that reef structures can be utilized by estuarine fauna.

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