HCNSO Student Theses and Dissertations

Defense Date

2007

Document Type

Thesis

Degree Name

M.S. Marine Biology

First Advisor

Richard E. Spieler

Second Advisor

Paul T. Arena

Third Advisor

Robin L. Sherman

Abstract

A beach renourishment project was initiated in May 2005 and completed in February 2006 to restore 11.1 km of shoreline in Broward County, Florida, USA. For mitigation of predicted nearshore hardbottom burial, a boulder reef totaling 3.6 ha was deployed in 2003. To examine the replacement value of the mitigation relative to fishes, this study compared fish assemblages on boulder reef to those on adjacent natural hardbottom. Twenty-five natural hardbottom sites and twenty-five boulder reef sites were surveyed six times between March 2005 and August 2007. Two non-destructive visual census methods, a transect count (30 m long x 2 m wide x 1 m high) and a 20 minute rover diver count (approximately 30 m x 30 m), were conducted at each site to assess abundance and species richness. On transect counts, 7,117 fishes of 96 species were counted on natural hardbottom, while 11,769 fishes of 119 species were counted on boulder reef. Across both survey types, a total of 271 species was recorded. Significant differences among reef fish assemblages were found in both abundance and species richness (pHaemulon spp., while boulder reef showed higher densities of early juvenile (2-5 cm TL) Haemulon spp. Boulder reef also had a higher abundance of fishes greater than 5 cm and piscivorous fishes in general. While boulder reef may provide a suitable habitat for many fishes, it does not mimic natural hardbottom-associated fish assemblages, nor does it provide a similar nursery habitat for juvenile fishes.

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