The Marine Fishes of Broward County, Florida: Final Report of 1998-2002 Survey Results

Ferro, Fleur; Jordan, Lance; Spieler, Richard

We inventoried fishes associated with three hardbottom reef tracts that are separated by sand and run parallel to the coast in sequentially deeper water offshore Broward County, Florida. Using SCUBA and the Bohnsack-Bannerot visual point count method, we recorded fish abundance, species richness, sizes (TL), and general habitat characteristics within an imaginary 15m cylinder extending from the substrate to the surface. Sites were sampled along transects at quarter nautical mile intervals along 18 nautical miles of coastline at western and eastern edges, and crest of each of the three reef tracts. A total of 86,463 fishes belonging to 208 species and 52 families were censused from 667 sites over four years (August 1998 to November 2002). Mean species richness, mean total abundance and mean total biomass of fishes increased significantly on each reef tract moving offshore (p<0.05, AN OVA, SNK). Tract differences may be due to a variety of variables, such as depth, current, refuge, food availability, and other habitat preferences. Differences were found within reef tracts based on edge or crest sites and position along reefs north or south of Port Everglades and Hillsboro Inlet. Sites within 5 na. mi. south of Port Everglades had lower total abundance and species richness (p<0.05, AN OVA) than the same number of sites located within 5 nautical miles north of the port. Also, south of Port Everglades, the western edge of the reef tracts had greater abundance and richness values than the eastern edge or the crest (p<0.05, ANOVA). In contrast, the eastern edge predominated in both abundance and richness north of Port Everglades (p<0.05, ANOVA). The reason(s) for these differences may be linked to topographic variables. In general, at count sites north of Port Everglades, the eastern edges of the reef tracts had a higher amount of vertical relief, and attendant refuge, than at southern count sites. Likewise, although regressions were weak, differences in species richness and abundance were related to bottom cover, rugosity, and depth to some extent. Hillsboro Inlet showed similar patterns. Sites within 3.75 nautical miles south of the inlet had lower abundance and species richness (p<0.05, ANOV A) than the same number of sites north of the inlet. These patterns could be influenced by effluent transport by the predominantly north-bound current running parallel to the coast. Density of juvenile grunts, an important forage base, was similar on the inshore and middle reefs, but was significantly higher than on the offshore reef. Of management interest, was a scarcity or absence of groupers and snappers observed over four years. Although juvenile red grouper were frequently seen (n = 232 at 667 sites), only two were above legal minimum size. No goliath or black grouper were recorded. A total of 10 gag, yellowfin, or scamp grouper was observed; none were legal. Among six snapper species, 219 of 718 were of legal size.

The Marine Fishes of Broward County, Florida: Final Report of 1998-2002 Survey Results

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