Implications of Natural Variation of Fish Assemblages to Coral Reef Management

In order to evaluate the impact of a planned beach renourishment project we obtained baseline data on hardbottom coral reef fish assemblages adjacent to the beach. During the summers of 2001 and 2003 we conducted 92 and 89 visual transect-counts, respectively, each 30x2x1m. Fish were recorded by species, abundance, and size class. Fish exhibited a 62.8% decrease in abundance between the 2001 and 2003 surveys. Juvenile Haemulon spp. (\u3c5cm total length, TL) alone decreased 72.8% in abundance and, due to their predominance, primarily drove the decrease seen for total abundance. The second most abundant species Halichoeres bivittatus, also primarily juveniles (\u3c5cm TL), contributed 8% of the total abundance and also showed a significant decrease between the 2001 and 2003 surveys. Even after removal of the two most abundant taxa, total abundance remained significantly lower the second survey year, suggesting the possibility of a community-wide decrease in abundance. However, the decrease between years was mainly due to a decrease in juveniles. When fish less than 5cm TL were removed from the dataset, no significant difference in abundance between years was detected. Species richness also declined significantly with fewer species noted in 2003 and eight fewer total species between years. Nonetheless, multivariate examination of assemblage structure did not indicate a difference between years. These results have important implications for determining potential anthropogenic change in fish assemblages (e.g. caused by beach renourishment)

Fish Assemblages Associated with Artificial Reefs of Concrete Aggregates or Quarry Stone Offshore Miami Beach, Florida, USA

Few studies have compared the suitability of different artificial reef construction materials in terms of their efficacy in acquiring diverse faunal assemblages. We compared the fishes associated with 12 co-located reefs constructed of limestone quarry boulders, concrete-gravel aggregate, or concrete-tire aggregate (four of each substrate) in 7 m of water, 200 m offshore Miami Beach, Florida, USA. All 12 reefs were deployed 100 m apart the same day in two lines of six. The four quarry stone reefs consist of a pile of 50 boulders each. The remaining eight reefs, of concrete-gravel aggregate and concrete-tire aggregate, were each constructed with 25 1.5 m edge and 25 1.2 m edge tetrahedron modules. Every two months from October 1998 to February 2001, SCUBA divers recorded fish species, abundance, and length, as well as spiny lobster, Panulirus argus, abundance. One hundred and forty-six species of fishes were recorded during the study period. The abundance and species richness of fish on each treatment exhibited a significant (p\u3c0.05) seasonal variation with summer months having the greatest numbers and winter the lowest. There was no significant difference in total fish or spiny lobster abundance or fish biomass amongst the three reef types (p\u3e0.05). Likewise, multi-dimensional scaling of Bray-Curtis dissimilarity indices did not indicate clustering of fish assemblages by reef type. Comparison of pre-deployment fish counts from the reef sites and neighboring hard bottom and jetty with counts from the same sites two years post-deployment indicate the artificial reefs increased both fish abundance and richness in the local area

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

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 was 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 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 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

Characterization of the Marine Fish Assemblage Associated with the Nearshore Hardbottom of Broward County, Florida, USA

Some shallow (\u3c7 m, water depth) nearshore hardbottom areas of southeast Florida have been reported to function as important juvenile fish habitat. Much of this area has been impacted by one or more local beach renourishments (sand fill to offset erosion). We characterized the nearshore fish communities and compared the fish assemblages adjacent to renourished beach to those adjacent to never-renourished beach along a 30-km stretch of coastline, primarily in Broward County, using three visual census methods. Two hundred transect-counts, 100 point-counts and 98 rover-diver counts were completed during June–August 2001. In transect- and point-counts, abundance of all fish species and their sizes were recorded; the rover-diver counts consisted of a simple species list. In total, 164 species and over 72,000 fish were recorded. The highest number of species (145) was recorded with the rover-diver counts. The transects-counts had 118 species and 109 species were recorded on the point-counts. With either all the sites adjacent to renourished beach pooled and compared to the pooled never-renourished sites or individual comparisons amongst renourished and neighboring never-renourished sites, no consistent differences were noted in fish abundance or species richness (ANOVA) or among fish assemblage structure (MDS plot of Bray–Curtis dissimilarity indices). However, although the data show no obvious distinct difference between the renourished and never-renourished sites, due to several important confounding factors (e.g., census methodology, longshore movement of sand fill) and the absence of baseline data prior to any renourishment, it would be premature to translate these results into management strategies. The assemblage structure, in terms of percentage of juvenile fish (\u3c5 cm) as well as percent contributions by family, was similar for the point-counts and transect-counts. However, in mean density per m2 of substrate, greater abundance and greater species richness values were recorded with the transect-counts than with the point-counts. Newly settled and early juveniles were the dominant component (\u3e84%) of the inshore fish community, consisting primarily (\u3e90%) of grunts (Haemulidae). After the grunts, the wrasses (Labridae) at about 5%, and damselfish (Pomacentridae) at roughly 2% were the predominant families. It is clear from this study and others that the nearshore hardbottom of Broward County is an important juvenile fish habitat, especially for grunts. However, the nearshore hardbottom does not appear to be obligate habitat for these fishes as fishes associated with this area are, apparently, not unique to the nearshore hardbottom either in species or ontogenic stage

Reef Fish Assemblage Structure Affected by Small-Scale Spacing and Size Variations of Artificial Patch Reefs

To examine how varying the distance between patch reefs affects reef fish assemblage structure, replicate concrete reef modules (∼ 1 m3 each) were deployed on sand bottom at 8 m depth off Ft. Lauderdale, Florida, USA (26°07N, 80°05W). Modules were positioned at the apices of one of four differently sized equilateral triangles. Triangular configurations had side lengths of: 25 m, 15 m, 5 m, and 0.33 m; each treatment with two replicates. Two additional configurations: (1) a solitary module (Single) and (2) two modules side by side (Double), also with two replicates, were deployed in order to examine the interaction of reef size with fish assemblages. SCUBA divers censused fishes monthly, for 2 years, recording the species present, their abundance and sizes (TL). Fishes were assigned to one of five length categories: \u3c 2 cm, \u3e 2–5 cm, \u3e 5–10 cm, \u3e 10–20 cm, and \u3e 20 cm. In general and excluding the smallest three-module spacing treatment (0.33 m treatment), which may have provided unique treatment-specific refuge, total fish abundance and richness were shown to increase when isolation distance increased. However, there were also species-specific and size class differences in response to isolation distance. The second part of this study indicated varying reef size, by doubling and tripling the number of reef modules, increased total fish abundance and species richness. Nevertheless, fish abundance and species richness did not change by an identical multiplier (e.g., doubling modules ≠ double abundance). These results suggest that scientists and marine managers alike should consider reef size and isolation as habitat attributes capable of altering the structure and dynamics of reef fish assemblages

Coral Reef Conservation Program (CRCP) Local Action Strategy (LAS) Project 3B “Southeast Florida Coral Reef Fishery-Independent Baseline Assessment” – 2012-2013 Interim Report

Reef fishes are important biologic, ecologic, and economic resources of the marine ecosystem which must be managed for sustainability. Until recently there was no long-term monitoring program in place to assess the condition of fish resources of the northern Florida Reef Tract (FRT) (northern Miami-Dade, Broward, Palm Beach, and Martin counties). An assessment/monitoring plan for the northern Florida reef tract was designed through a joint cooperative effort by scientists at the University of Miami Rosenstiel School of Marine and Atmospheric Science, NOAA-Southeast Fisheries Science Center and Nova Southeastern University Oceanographic Center (NSUOC). This report is a synoptic compilation of the two-year data collection from all partner agencies, and includes data from the 234 and 354 sites or Primary Sampling Units (PSUs) sampled in 2012 and 2013, respectively. The majority of the field work was accomplished through funding granted to NSUOC. Significant amounts of data were also collected by multiple partner agencies that were able to dedicate their time and resources to the project. In 2012 funding for the first year of data collection was awarded by Florida Department of Environmental Protection (FDEP) to NSUOC on July 1st, 2012. Funding for a second year of sampling was awarded by National Oceanic and Atmospheric Administration (NOAA) Coral Reef Conservation Program (CRCP) to NSUOC through the National Coral Reef Institute Cooperative Agreement on June 18, 2013. Field sampling for each year began in May and ran through October. Funding for a third year of data collection (2014) and a final report was awarded by NOAA CRCP to NSUOC. Over the course of the two-year study period for this interim report, \u3e170,000 individual fish of 266 species were recorded. Total mean density for all sites and strata combined for both years was 162 fishes/SSU. For 2012, mean density was 151 fishes/SSU; in 2013 it was 168 fishes/SSU. However, in general, 2012 counts were higher at most sites. When low vs. high slope strata were compared, the high slope strata showed higher fish density. Likewise, species richness was higher at most sites in 2012 than 2013 and was also significantly higher for both years on sites with high slope. Multivariate analyses showed patterns in the reef fish communities associated with benthic habitats. Water depth was a primary determinant of fish distribution with differences in assemblages between shallow and deep sites. Also most of the surveys in the southern regions (Broward-Miami, Deerfield, and South Palm Beach) clustered tightly together indicating high similarity between communities in the deep habitats within these regions. Conversely, fish communities in North Palm Beach and Martin were much more variable and mostly separated in disparate areas of the plot. This suggests that the Martin and North Palm Beach fish communities are distinctly different from the southern regions. The dataset, in its entirety, provides the opportunity for further mining to examine individual species and reef fish assemblage correlations with a host of abiotic and biotic variables. Thus, from both management and ecological-sciences perspectives, it is a valuable resource. It is already clear there are significant differences in the geographic distribution of reef fishes at local and regional scales. There are interacting strata and latitudinal differences in total reef fish abundance, species distribution, sizes, and assemblage structure. The combination of data from all three years will provide a complete regional baseline fishery-independent assessment

Depth-Variable Settlement Patterns and Predation Influence on Newly Settled Reef Fishes (Haemulon spp., Haemulidae)

During early demersal ontogeny, many marine fishes display complex habitat-use patterns. Grunts of the speciose genus Haemulon are among the most abundant fishes on western North Atlantic coral reefs, with most species settling to shallow habitats (≤12 m). To gain understanding into cross-shelf distributional patterns exhibited by newly settled stages of grunts (\u3c2 cm total length), we examined: 1) depth-specific distributions of congeners at settlement among sites at 8 m, 12 m, and 21 m, and 2) depth-variable predation pressure on newly settled individuals (species pooled). Of the six species identified from collections of newly settled specimens (n = 2125), Haemulon aurolineatum (tomtate), H. flavolineatum(French grunt), and H. striatum (striped grunt) comprised 98% of the total abundance; with the first two species present at all sites. Prevalence of H. aurolineatum and H. flavolineatumdecreased substantially from the 8-m site to the two deeper sites. In contrast, H. striatum was absent from the 8-m site and exhibited its highest frequency at the 21-m site. Comparison of newly settled grunt delta density for all species on caged (predator exclusion) and control artificial reefs at the shallowest site (8-m) revealed no difference, while the 12-m and 21-m sites exhibited significantly greater delta densities on the caged treatment. This result, along with significantly higher abundances of co-occurring piscivorous fishes at the deeper sites, indicated lower predation pressure at the 8-m site. This study suggests habitat-use patterns of newly settled stages of some coral reef fishes that undergo ontogenetic shifts are a function of depth-variable predation pressure while, for at least one deeper-water species, proximity to adult habitat appears to be an important factor affecting settlement distribution

Southeast Florida Coral Reef Fishery-Independent Baseline Assessment

Reef fishes are important biologic, ecologic, and economic resources of the marine ecosystem which must be managed for sustainability. Until recently, there was no long-term monitoring program in place to assess the condition of reef fish resources of the northern Florida Reef Tract (FRT) (northern Miami-Dade, Broward, Palm Beach, and Martin counties). An assessment/monitoring plan for the northern portion of the Florida reef tract was designed through a joint cooperative effort by scientists at the University of Miami, Rosenstiel School of Marine and Atmospheric Science (RSMAS), National Oceanic and Atmospheric Administration (NOAA)-Southeast Fisheries Science Center (SEFSC) and Nova Southeastern University Oceanographic Center (NSUOC). This report is a synoptic compilation of a three-year data collection from all partner agencies, and includes data from the 232, 324, and 308 sites or Primary Sampling Units (PSUs) sampled in 2012, 2013, and 2014, respectively. The majority of the field work was accomplished through funding provided to NSUOC by the NOAA Coral Reef Conservation Program (CRCP), with supplementary funding provided by FDEP-CRCP. Significant amounts of data were also collected by multiple Southeast Florida Coral Reef Initiative (SEFCRI) partner agencies that were able to dedicate their time and resources to the project. Field sampling for each year began in May and ran through October. During the three-year study period, \u3e560,000 individual fish of 289 species were recorded. Total mean density for all sites and strata combined for all three years was 170 fishes/SSU (Second-Stage Sample Unit = SSU or site, 177 m2). For 2012, mean density was 151 fishes/SSU; in 2013 it was 168 fishes/SSU; and in 2014 it was 186 fishes/SSU. When low vs. high slope strata were compared, the high slope strata showed higher fish density. Multivariate analyses showed patterns in the reef fish communities associated with benthic habitats. Water depth was a primary determinant of fish distribution with differences in assemblages between shallow and deep sites. Also most of the surveys in the southern regions (Broward-Miami, Deerfield, and South Palm Beach) clustered tightly together indicating high similarity between communities in the deep habitats within these regions. Conversely, fish communities in North Palm Beach and Martin were much more variable and mostly separated in disparate areas of the plot. This suggests that the Martin and North Palm Beach fish communities are distinctly different from the southern regions. The dataset, in its entirety, provides the opportunity for further mining to examine individual species and reef fish assemblage correlations with a host of abiotic and biotic variables. Thus, from both management and ecological-sciences perspectives, these data are a valuable resource. It is already clear there are significant differences in the geographic distribution of reef fishes at local and regional scales. There are interacting strata and latitudinal differences in total reef fish abundance, species distribution, sizes, and assemblage structure. The combination of data from all three years provides a complete regional baseline fishery-independent assessment

A Comparison of Reef Fish Assemblages on the East and West Sides of Central Eleuthera, Bahamas

Eleuthera is a long, narrow crescent-shaped Atlantic margin island on the eastern extremity of the Great Bahama Bank in the central Bahamas. It is 144 km long and less than 5 km at its greatest width. Fringing reefs with substantial vertical relief (to 5 m in depths of 6 m) are found approximately 500 m offshore on the eastern side of the island facing the Atlantic Ocean. The western side of the island has stretches of rock cliffs and large fallen boulders providing substrate with similar vertical relief. No open passes exist between the two sides of the island and thus no direct larval transport from one side to the other appears possible. We compared post-settlement fish assemblages and larval supply on either side of central Eleuthera near Governor’s Harbour quarterly from July 2003 until July 2004. Twelve point-counts were performed at two replicate sites on both sides of the island to census juveniles and adults. Abundance, as well as average, maximum and minimum lengths of species present were recorded. Three light traps were moored at each of the same sites 40-50 m from the reef for three to five nights around the new moon to examine larval supply. Fish collected in the light traps were preserved and transported to the lab. They were identified, enumerated, and standard length was measured. Preliminary analyses of point-count and light trap data indicate dissimilar assemblage structure between the two sides of the island, with significantly greater fish abundance and species richness on the eastern side

Marine Biological Monitoring in Broward County, Florida: Year 2 Annual Report

A study has been undertaken to monitor Broward County, Florida (southeast Florida) coral communities, reef fish assemblages and sedimentation rates in relation to possible effects from a proposed extensive beach renourishment (restoration) project. Coral communities and reef fish assemblages will be monitored at a total of 23 stations distributed offshore Broward County. This monitoring effort will characterize and quantify populations of scleractinian (stony) corals, octocorallian (gorgonian) corals, sponges, and reef fishes. In addition, sediment traps located at each station will be sampled and analyzed. This document reports the data collected during the second year of this project. Coral communities and fish assemblages were monitored at each of the 23 sites between September and October 2001. In addition, sedimentation analysis for the January, March, May, July and September 2001 collections were conducted. For September/October 2001, mean (± 1 S.D.) stony coral density for the 23 sites was 2.62 ± 1.85 colonies/m2. Mean stony coral coverage was 2.39 ± 3.96%. Mean gorgonian density was 7.91 ± 8.01 colonies/m2 and mean sponge density was 14.09 ± 6.93 colonies/m2. First Reef sites had greater mean stony coral coverage but lower gorgonian and sponge density than Second and Third Reef sites. First Reef coral cover was much lower than the Third Reef when the First reef site, FTL4, was removed from the analysis. FTL4 had much greater stony coral cover than the mean cover for the remaining First Reef sites (19.95% compared to 1.45%). Shannon-Weaver Diversity Indices performed on the overall transect data resulted in values of 1.45 ± 0.53 and 1.72 ± 0.44 for cover and number of species respectively. Overall evenness was 0.77 ± 0.14 for number of species and 0.64 ± 0.21 for cover. There was no significant difference determined between the January/February 2001 site visit data and the September/October 2001 site visit data for mean stony coral density and cover. Mean octocoral density also did not differ significantly between these site visits, but mean sponge density was significantly less in September/October 2001 than in January/February 2001. Stony coral density, stony coral coverage, gorgonian density and sponge density data collected from the 18 monitoring sites established in 1997 and visited yearly from 1997 to 1999 were analyzed. No significant difference in yearly mean stony coral density, mean stony coral cover and mean gorgonian density was determined. Mean sponge density did show significant differences with 1998 sponge density greater than 1997. Trends in fish density were similar to those trends identified within the coral community transects. The greatest density of fishes occurs on the Third Reef followed by the First and Second. A difference in richness was seen amongst the three Reefs with the First Reef having the lowest number of species. The differences noted in abundance, density, and richness between the data collected in January/February 2001 and in September/October 2001 confirm previous reports of temporal differences in the fish assemblage offshore Broward County (Spieler 1998). The First Reef had a statistically higher rate of sedimentation than both the Second and Third Reefs when data from January-September 2001 were pooled. Pooled site data showed that January 2001 and May 2001 samples had the greatest sedimentation rates. The grain size for sites on the Third Reef was significantly smaller than both the First and Second Reefs. When site data were pooled, January 2001 had a significantly larger mean grain size than the other four sampling intervals in 2001. Data collected and analyses completed during this monitoring project will be used to help evaluate effects from the proposed beach renourishment project