This study investigates the effects of sediment stress on tissue and cellular structure in the cultured coral Monastraea cavernosa. The goal of this research is to quantify fine and ultrastructural data and examine potential correlation between sediment stress and changes in coral tissues and associated zooxanthellae dinoflagellate cells. An experiment in which colonies of this species were exposed to sediment stress provided the samples for this study (Vargas-Angel et al., in press). In that experiment, sediment stress was induced by the application of sediment (approximately 200-225 mg/cm2) twice daily over a four-week period. At the end of each week, a colony from each experimental tank was sacrificed and prepared for histological analysis. In the present study the paraffin blocks from this experiment were re-sectioned and stained for additional analysis. The sections were then examined for variability in the following stress parameters: 1) Symbiotic zooxanthellae and mucosecretory cell size (coenosarc, oral disk, and the middle polyp), 2) Epithelium thickness (coenosarc and oral disk), and 3) Zooxanthellae mitotic index (cell doublets) of cells (coenosarc and oral disk). Transmission electron microscopy (TEM) was also utilized for an ultrastructural study of coenosarc tissue and associated zooxanthellae. These included: 1) Zooxanthellae size comparisons with cells assessed using histological measurements, 2) Zooxanthellae accumulation vacuole size, and 3) Zooxanthellae nuclei chromosome bundle number. Significant differences were found in the tissues and cells examined from different areas of the polyp as well as with duration of sanding treatment. In sanded corals, zooxanthellae, mucosecretory cell sizes, and the mitotic index increased significantly through week three, and decreased significantly in week four. In addition, the epithelium thickness decreased significantly throughout the study and indicates that sedimentation causes atrophy (thinning) of the epithelium. Sediment stress related increase in mucosecretory cell (MSC) size indicates that coral mucus production increased under sediment stress. This increase in MSC cell size is correlated with subsequent increase in both zooxanthellae size and mitotic index. These effects may be a result of nutrient enrichment due to the chemistry of the mucus. In addition, this study also demonstrates that zooxanthellae sizes are distinct in different areas of the polyp and may respond differently to sanding stress. Therefore, current protocols for extracting zooxanthellae from corals, which results in combining cells from several sections of the polyp, may not discriminate tissue-specific zooxanthellae characteristics. Future culture-work in which examination of mucus related nutrient enrichment effects, and ultrastructural/ biochemical tissue-specific characteristics of the zooxanthellae are proposed.

This study was survey of disease distribution and abundance relating to coral diseases present in Broward County. Data of the 1330 scleractinian coral individuals found, 88 showed signs of disease. 19 coral species, 3 diseases and bleaching were represented. Diseases affected 9 of the species. Bleaching was the most common disease noted in this survey, followed by dark spot, red band, and yellow band. Disease distribution appears to be scattered on the reef system. No apparent patterns were found when grouped by reef or corridor locations. MDS cluster analysis revealed a clumping of disease, but this was not correlated with location. Sites with more disease susceptible species tended to be clumped together. Species diversity may play a role in the amount of disease present. Lower species diversity may cause an area to me more susceptible to disease. The more species located within an area, the less affect a disease affecting a subset of species would have.

The yellow stingray, Urobatis jamaicensis, displays an aplacental viviparous mode of reproduction. Although each embryo is initially nourished only from a yolk sac, later trophonemata within the maternal uterus secrete histotroph to provide further nutritional sustenance. Histotroph in some stingray species is thick and may be ingested orally. However, the uterine fluid of U. jamaicensis remains thin and watery throughout gestation. It is hypothesized that the internal gill vasculature of U. jamaicensis embryos may be involved in nutrient uptake. The purpose of this study was to provide an anatomical basis for future physiological tests of this hypothesis. I examined the development of gill vasculature in the yellow ray throughout gestation. Corrosion casting with Mercox™ was utilized to create replicas of the vasculature within embryo gills and maternal uteri at various stages of gestation. Examination of these casts under scanning electron microscope revealed variation in the density of capillaries among trophonematal samples, though correlation of density with gestational stage could not be determined. The most marked changes in vascular configuration of the gills occur in the earliest castable stages of gestation. These changes included development of afferent external gill filament vessels and progression from paired dorsal aortae to a single fused dorsal aorta. Internal gill vasculature was found to nearly match that of an adult by the time the external gill filaments had fully regressed and yolk sac had been exhausted. Confirming the correlation that internal gill vasculature is fairly well developed by the time initial nutrient structures have regressed provides support for the hypothesis that these vessels may be involved in nutrient uptake in later stage embryos, providing sufficient surface for exchange. Physiological investigation is needed to examine their possible function in this role. Examination of embryo casts also revealed characteristics of the branchial vasculature not previously reported in adult specimens. These include the presence of prelamellar sph2 sphincters, intertrematic branches, afferent distributing arteries which supply blood to many afferent filament arteries, resulting in greater interconnection of the filaments, and observation that the afferent branchial artery in the first hemibranch supplies blood directly to the afferent filament arteries on the dorsal half of this arch.

Chapter 1 The only coral reef ecosystem in the continental USA occurs off southeastern Florida and is under considerable strain due to intense urbanization and coastal development in this region. Coherent management and conservation efforts for this rapidly degrading ecosystem will benefit from knowledge about the patterns of genetic connectivity along the entire Florida reef tract. Because of their substantial biomass and extensive species diversity, the Porifera are an important model for investigating connectivity among coral reefs in Florida. We determined the genetic population structure of a common brooding species, the branching vase sponge, Callyspongia vaginalis, along 465 km of the Florida reef system from Palm Beach to the Dry Tortugas based on sequence data from the mitochondrial cytochrome oxidase subunit 1 (COI) gene. Populations of C. vaginalis were highly structured (overall ΦST=0.33), in some cases over distances as small as tens of kilometers. However, nonsignificant pairwise ΦST values were also found between a few relatively distant sampling sites suggesting that some long distance dispersal, perhaps by means of larval transport via sponge fragments, may occur along continuous, shallow coastlines. Indeed, sufficient gene flow appears to occur along the Florida reef tract to obscure a signal of isolation by distance, but not to homogenize COI haplotype frequencies. There was strong genetic differentiation among most of the sampling locations highlighting the fact that recruitment in this species is largely locally source-driven and that management needs to occur on a local scale. The C. vaginalis population at the northern end of the Florida reef tract (Palm Beach) had the lowest genetic diversity observed. This portion of the reef tract generally receives much less management attention than the southern reefs of the Florida Keys National Marine Sanctuary, and may require targeted conservation efforts for biodiversity preservation. Chapter 2 The Porifera constitute a substantial part of the biomass on coral reefs, frequently have higher species diversity than corals and algae, and promote species richness through the fauna they support, making this phylum an important model for investigating connectivity among coral reefs. However, sponges have been neglected in population level genetic studies, particularly in the Caribbean. We determined genetic connectivity among populations of the branching vase sponge (Callyspongia vaginalis) by analyzing DNA sequence variation in 511bp of the mitochondrial cytochrome oxidase (COI) gene from 401 sponges sampled at 14 locations in Florida and the Caribbean. A significant signal of isolation by distance (P < 0.0001) was detected and an analysis of molecular variance (AMOVA) showed a pattern of high genetic structure among populations (ΦST = 0.57, P < 0.0001) with 82 of 91 pairwise comparisons being significant. Statistical parsimony analysis revealed two highly divergent haplotypes, suggestive of cryptic speciation. Inferences from a nested clade analysis suggested a northward movement out of the hypothesized ancestral population in Central America and into the Gulf of Mexico and Florida. The strong genetic structure observed Caribbean-wide indicates that there is little gene flow among populations and that recruitment of C. vaginalis is driven largely from local sources. As a result, recovery of this species on degraded reefs by seeding from distant, healthier reefs is unlikely. These results underscore the need for reef management and conservation efforts on small spatial scales.

This work examined the leucothoid amphipods collected during the Hourglass cruises (R/V Hernan Cortez 1965 – 1967) across the West Florida Shelf (Joyce et al., 1969), focusing on species identification and distributional patterns. Five of the six species identified were known from Caribbean and eastern Atlantic waters. This collection expands the known range of all five species to the Gulf of Mexico. The sixth species, Leucothoe L, is diagnosed as new. Although 16 stations were sampled, data was analyzed statistically only from the 10 stations where leucothoids were found, (stas. A-E and I-M). A SIMPROF dendogram generated from relative abundance data identified three groups of stations with similar community composition (Group 1 - I, A, J at the 100% level; Group 2 - D, C, L at the 83% level, and Group 3 - E, M, B, K at the 87% level). A SIMPER analysis revealed that L. kensleyi was the most statistically influential species in community composition when comparing groups 1 versus 2 and 1 versus 3, while L. ashelyae, L. barana, L. kensleyi, and L. urospinosa contributed equally to the difference seen between groups 2 and 3.

Beach erosion is an ongoing problem in South Florida. Beach replenishment has been the primary means of maintaining these economically important beaches, and dredging offshore sand deposits, adjacent to reef tracts, has been the pervasive method since the 1970's. Over the past ten years, greater attention has been paid to potential impacts dredging can have on adjacent reef communities, which has led to increased monitoring efforts. With the increase in monitoring efforts, scope has expanded from a strict focus on the benthic community to include the fish communities. This study evaluates the effects of dredging on reef fish communities associated with two separate beach replenishment projects, offshore of Miami-Dade County, Florida, U.S.A. Monitoring programs were developed and conducted by the Miami-Dade, Department of Environmental Resources Management (DERM). Monitoring took place between March 1997 and September 2000, with one project in northern portion of the county, off offshore of Golden Beach, and the other in the southern portion offshore of Key Biscayne. Both monitoring programs employed a Before After Control Impact design, with established test and control reef stations. Eight reef fish visual point count censuses (Bohnsack and Bannerot, 1986) were performed at each station prior to dredging, immediately following dredging, and three periods at bi-quarterly intervals after that. In general evaluations of both project,s showed no indications that dredging activities had major impacts on the fish communities of adjacent reefs. For the Golden Beach project, there was one aspect of the analysis, which may be indicative of dredging related impacts; was species richness at one test station declined significantly following dredging activities (ANOVA p=0.047). However, in terms of abundance, diversity and Multidimensional scaling (MDS) plots of the Bray-Curtis dissimilarity index did not indicate that dredging activities impacted the test station. During the monitoring period of the Key Biscayne project, the south Florida region was impacted by two tropical storm events, which obscures the isolation of impacts associated with dredging. Changes in the reef fish communities, consistent with the impact and recovery of the tropical storms are evident in species richness, abundance, and MDS plots of the Bray-Curtis dissimilarity index, at both the test and control stations.

Differences in whistle types between species and populations of dolphins may arise from differences in body size, environmental conditions, geographic separation, and vocal learning between animals. Assessing vocalization differences between populations of delphinids, as well as the mechanism of divergence, has become a subject of interest since acoustic differences may help to distinguish between populations at sea. In this study, bottlenose dolphin (Tursiops truncatus), Atlantic spotted dolphin (Stenella frontalis), and pilot whale (Globicephala sp.) populations in U.S. waters were quantitatively compared to determine if differences in whistle structure exist between both neighboring and geographically separated populations. Comparisons were made for nine whistle characteristics between northern Gulf of Mexico and western North Atlantic populations of bottlenose dolphins and pilot whales and between continental shelf and offshore populations of Atlantic spotted dolphins in the western North Atlantic. Whistle characteristics were measured for 3,836 pilot whale whistles, 1,703 Atlantic spotted dolphin whistles, and 2,715 bottlenose dolphin whistles recorded between 2002 and 2004. Differences between groups were evaluated using principal components analysis and discriminant analysis. Bottlenose dolphin whistles in the Atlantic were significantly different (Hotelling's T-squared, p < 0.0001) from those in the Gulf of Mexico, differing chiefly in the whistle characteristics of end frequency, duration, and the number of inflection points. Offshore Atlantic spotted dolphin whistles were significantly different (Hotelling's T-squared, p < 0.0003) from those of the continental shelf population, differing principally in high frequency, central frequency, and bandwidth. No significant difference was found between pilot whale whistles in the two ocean basins. The whistle differences demonstrated in this study indicate that acoustic divergence exists between distinct populations and may arise from geographic isolation or due to habitat separation between neighboring but genetically distinct groups. This study suggests that acoustic studies are an excellent and costefficient method to assess population structure.

Ecological communities consist of multiple predators and prey, in which predators have varied hunting strategies and foraging preferences and the prey have varied antipredator responses. Multiple predators can combine to have linear or non-linear effects that can either enhance or reduce the risk of predation experienced by prey. How this occurs in novel systems where predators and prey lack a coevolutionary history, and thus prey may be naïve to predation threats posed by non-indigenous predators, is not well understood. This study examined the predatory effect of two non-native fishes, the African jewelfish (Hemichromis letourneuxi) and the Mayan cichlid (Cichlasoma urophthalmus) and the behavioral responses of a native Everglades prey assemblage. We used an in situ enclosure experiment to compare predation rates and prey selectivity, followed by behavioral trials in the laboratory to examine predator foraging tactics and prey responses to predation (microhabitat use and activity levels). When both predator species were present, we found no evidence that native prey experience a release from predation resulting from interference competition. C. urophthalmus exhibited a higher predation rate and different foraging preferences than H. letourneuxi. Overlap in habitat domain of predators and prey was important in predicting prey consumption, as prey were most often consumed when they occupied the same space in the water column as predators. The predators were found to be functionally different and the behavioral responses of prey varied among species in response to the non-native predators. It is important to examine the behavior of predators and the responses of prey to determine the nature of these multiple predator interactions and the resulting impacts of non-native predators, especially as these predators continue to spread in the Everglades ecosystem.

There are currently over 300 sites in nearly 40 countries where a variety of marine animals are provided supplemental food by humans. The influence of this supplemental feeding on the behavior, physiology, growth, reproduction and movements of the animals involved is seldom known. Intentional supplemental feeding of the southern stingray, Dasyatis americana, has occurred at Stingray City (SC) and Stingray City Sandbar (SCS) at Grand Cayman since 1986. There are no specific regulations governing the feeding of D. americana at Grand Cayman, and neither the species nor the feeding sites are afforded any official protective status. This study investigated how supplemental feeding influences the movement patterns of D. americana at Grand Cayman, including activity spaces, rates of movement, site fidelity and diel patterns. This research is the first detailed investigation into the influence of supplemental feeding on the movement patterns of a marine animal. The objectives of this study were to investigate and compare the movement patterns of D. americana at supplemental feeding sites and non-feeding ‘wild’ control sites. Passive Integrative Transponder (PIT) tags were implanted in 327 stingrays, 183 of which were recaptured; 100% of recaptured stingrays retained their tags over the duration of the study, based on tissue sample scarring. External tags were attached to 35 stingrays. Tagging data indicate that a spatially isolated community of approximately 160 D. americana utilize SCS. Seven wild and seven provisioned stingrays were tracked manually from five to 72 h, and five mature females at SCS were tracked automatically using an array of two bottom monitors. Provisioned female stingrays at SCS utilized significantly smaller 24 h activity spaces (0.132±0.079 km2) than wild female stingrays (0.876±0.171km2). Both groups utilized significantly larger activity spaces at night than during the day. However, there was a marked difference in the diel activity levels between provisioned and wild stingrays: provisioned stingrays were active over a small area during daytime supplemental feeding, whereas wild stingrays were more active and foraged during the night (nocturnal). Average rates of movement did not significantly differ between the two groups. Tidal phase had no effect on activity space size or rate of movement for either group. The core areas of provisioned stingrays showed significantly more overlap than those of wild stingrays, indicating that supplemental feeding has disrupted the spatial distribution of the community at SCS and increased the local density of D. americana to atypical levels. Provisioned female stingrays consistently frequented SCS during periods of supplemental feeding and exhibited long term (at least up to one year) site fidelity to this site. These findings suggest that provisioned stingrays are highly conditioned to the supplemental food resources provided at SCS. Provisioned stingrays exhibited optimal foraging and have reduced and centralized their core areas and activity spaces at SCS in order to maximize their accrual of food resources. The availability of food resources is a significant factor regulating the size and location of core areas and activity spaces, population density and the diel activities (i.e. the spatial and temporal distribution) of D. americana at Grand Cayman.

The penaeid shrimp, Litopenaeus vannamei, is the most important species in the shrimp aquaculture industry in the Western Hemisphere, and its cultivation in fresh and low-salinity well waters is one of the most exciting new areas of shrimp culture research. However, no research has been carried out using South Florida aquifers. The range of salinity this species encounters in nature makes it attractive for culture in inland, low-salinity growout conditions. This study investigated the feasibility of culturing L. vannamei in low salinity and fresh well waters of South Florida. Two sets of experiments were carried out, an acclimation study and a cultivation study. In the acclimation study, a total of 150 5-day-old postlarval shrimp (PL 5) were acclimated to five water types over a 6-day period: Shallow Broward Well water (SBW), Deep Broward Well water (DBW), Shallow Broward Well water treated with agricultural Salt (SBWS), Deep Broward Well water with Salt (DBWS) and Diluted SeaWater (DSW). Each water type had three one-liter replicates stocked with 30 PL 5’s. After a two-day acclimation period, test organisms demonstrated marked differences in survival rates. Deep Broward well water was the most successful (79% survival), followed by Shallow Broward well water (68%), and diluted seawater (44%); all waters treated with agricultural salt had low survival rates. An ANOVA on the DBW and SBW data shows that survival results do not differ statistically between the two treatments. In the cultivation study, the growth of L. vannamei was monitored over a 35-day period in Shallow Broward Well water (SBW) and Deep Broward Well water (DBW). Three hundred test organisms were monitored in separate recirculating systems for each water type. Growth was measured in weight (in gm), total body length, width of head, and width of body (all in cm). Nitrite, nitrate, ammonia, dissolved oxygen and temperature were also monitored. Statistically significant growth occurred in both water types in all categories measured. Growth rates were significantly higher in DBW than in SBW in all categories measured over the 35-day study.