Data collected by fisheries observers aboard U.S. pelagic longline vessels were examined to quantify and describe elasmobranch bycatch off the southeastern U.S. coast (22° - 35° N, 71° - 82° W). From 1992 to 1997, 608 "sets" or gear deployments were observed which resulted in the capture of 2649 elasmobranchs (17.5 percent of the total catch). Of the 21 elasmobranch species observed, silky sharks, Carcharhinus falciformis, were numerically dominant (34.4%) followed by dusky, C. obscurus (16.3%), blue, Prionace glauca (8.9%), unidentified sharks (6.4%), tiger, Galeocerdo cuvier (5.9%), and scalloped hammerhead, Sphyrna lewini (5.7%). The catch status of the animal (alive or dead) when the gear was retrieved varied widely depending on the species, with high mortalities seen for the commonly caught silky and dusky sharks and low mortalities for rays, blue sharks, and tiger sharks. Discard percentages depended mostly on the marketability of the species, ranging from low discards (20.4 %) for shortfin mako, Isurus oxyrhinchus, to high discards for blue (99.5 %), tiger (96.7 %), and rays (100 %). Percentages of live and dead discards also varied considerably among species. Analysis of variance indicated significant catch rate differences among seasons for silky, dusky, blue, oceanic whitetip (C. longimanus), sandbar (C. plumbeus), and shortfin mako sharks. Mean fork lengths indicated the majority of the observed bycatch, regardless of species, was immature, and significant seasonal variation in fork length was found for several species including silky, dusky, blue, night (C. signatus), and oceanic whitetip sharks. While sex ratios overall were relatively even, blue and tiger shark catches were dominated by females. Only silky sharks showed significant seasonal sex ratio variation, with a higher proportion of males observed in the winter. Bootstrap methods were used to generate yearly mean catch rates (catch per unit effort) and 95 % confidence limits. Catch rates were in turn used to generate an overall estimate of the numbers of elasmobranchs discarded dead and alive during 1992-1997. These estimates predict 38,775 (18,780 and 63,751, lower and upper 95 % confidence limits) and 31,859 (13,837 and 56,712, lower and upper 95 % confidence limits) sharks were discarded alive and dead, respectively, during this time period. Possible implications of the results of this study for shark fishery management are discussed for the most common bycatch species.

Sessile marine invertebrates often exhibit non-random distributions both horizontally and vertically. The larvae of scleractinian corals settle and metamorphose in response to numerous environmental stimuli including substrate composition and the presence of chemical signals, such as extracts of certain red crustose coralline algae. In this study, seven different substrates common to past research efforts were infused with an extract from the red crustose coralline alga, Hydrolithon boergesenii, and placed on the bottom of the ocean, as were similar plates containing no extract. Substrate plates were deployed during the months following the August 1999 coral-spawning event on a reef near Fort Lauderdale, Florida. Larvae settled on plates placed on the shoreward side of the reef 2.12 times as often as plates placed on the seaward side of the reef. This difference was significant whether the plates contained algal extracts (p=0.004 by two-way ANOVA) or did not contain algal extracts (P = 0.003 by Two-way ANOVA). Reef location also influenced settling independent of plate composition. Peak settlement was observed on unglazed ceramic tiles on the shoreward side of the reef, while the lowest settlement was observed on glass plates on the shoreward side of the reef. Two-way ANOVA with replication showed significant differences in plate material (P = 0.031), presence or absence of algal extract (P = 0.002), and in the interaction of these variables (P = 0.009). Larvae settled on plates containing the algal extracts 2.60 times as often as plates without algal extract. Multiple analysis of variance (MANOVA) for the interaction of all variables indicated significant interactions for extract presence (P = 0.002), reef zone location (P = 0.036), and plate material (P = .031). The interactions between algal extract presence and reef zone were also significant (P = 0.009), as were the interactions between plate material and algal extract presence (P = 0.009). Simultaneous MANOVA for all variables was not significant (P = 0.071), probably due to large variation in settling plate composition, variation in the concentration and activity of the algal extracts applied to the plates, as well as variation in the microhabitat across the reef.

A collaborative project examined the disease status of dolphins that stranded along the coastline of Florida from 1996 to 2002. This study reviewed 68 freshly dead stranded dolphins (57 Tursiops truncatus and 11 others from four species). Analysis of stranding demographics and histopathologic data from the Southeastern United States Stranding Network provided important information on the prevalence of lesions in relation to sex, geographic location, season, and length in T. truncatus. The histopathologic results obtained from the other species were from an extremely small sample size and thus only provided limited insight into the diseases impacting them. Cardiomyocyte degeneration and lymphoid depletion were found in all five species examined. Some of the pathologic findings found in >20% of the T. truncatus tissues examined included pneumonitis, pulmonary fibrosis, edema, angiomatosis, nematodiasis, hepatic fibrosis, hepatocellular atrophy, glomerulonephritis, cardiomyocyte degeneration, cardiac fibrosis, lymphoid depletion, lymphadenitis, lipid depletion, gastritis, and enteritis. There were no trends seen in the histopathologic data related to sex, geographic area, or season. There were however differences in the prevalence of some lesions in relation to length class in the lung, spleen, kidney, and heart. There was a significant difference between length classes in the prevalence of the following lesions, angiomatosis (p=0.0062) in the lung, lymphoid depletion (0.043) in the spleen, glomerulonephritis (p=0.00009) in the kidney, and cardiomyocyte degeneration (p=0.022) and fibrosis (p=0.0021) in the heart, with a tendency towards more lesions in larger animals. The results of this investigation suggest that these lesions are more prevalent in larger, presumed to be older, stranded T. truncatus. The histopathologic results presented here provide important information on the diseases impacting T. truncatus around Florida, which can be used as a basis for future comparisons.

The occurrence of stranded cetaceans has been of interest since Aristotle and numerous theories have been advanced to explain stranding phenomena. The causes(s) of mass strandings remain unresolved, but recent investigations suggest the importance of environmental rather than biological aspects. Little emphasis has been placed on the importance of seasonal fluctuations in the number of mass strandings. Stranding data for the past 20 years in Florida, collected by the Southeastern U.S. Marine Mammal Stranding Network, show a peak in mass strandings on the Florida east coast during the winter and spring and on the Florida west coast and Keys during the summer and fall. The infrequency of mass strandings suggests that a number of factors must coexist for a stranding to occur. Correlations were found between downwelling-favorable wind conditions and stranding events. Seasonal variations in wind speed and direction create frontal convergences in the ocean environment, which can be tracked by cetaceans. Such wind induced physical oceanographic changes, if followed by cetaceans, may explain why species move from the shelf-break to the near shore environment. In addition, strandings are more likely to occur on beaches that slope gently until a point of more rapid drop-off, allowing deep water to be located nearshore. This analysis suggests that the prevailing winds and high relief areas located close to shore are important factors in the initial stages of a stranding due to their causative effect on frontal structures the week prior to an event.

Long term monitoring of coral reefs on the northwest coast of Roatán, Honduras, has documented significant changes in coral cover over a seven-year period. Twenty photographic quadrats were permanently installed at approximately 12 m depth at each of three study sites located on the northwest coast of Roatán. Photographs were taken at six or twelve month intervals from 1996 through 2003. This observation period included a massive bleaching event which began in late-September of 1998, and Hurricane Mitch which struck in October of the same year. A measurement of projected surface area (PSA, cm2) was used to estimate total coral coverage. Changes in colony number, percent cover, species diversity and recruitment of all scleractinian corals were monitored within the quadrats. During the seven-year period, living coral cover decreased significantly from 30-34% to 17-20%. This represents net losses ranging between 32% and 50%. The greatest loss occurred in the year following the bleaching event and Hurricane Mitch and was largely due to the decline of the dominant reef building species Montastrea annularis, M. faveolata, and M. franksi. These three species accounted for 56% of total hard coral cover in 1996 and only 32% at the conclusion of the observation period. A sharp reduction in the total number of living colonies in the quadrats was observed with 217 of the 532 original colonies (41%) suffering complete mortality. While 117 coral recruits were identified during this period, recruitment mortality was high (40%) with only two cases of the massive frame building Montastrea species recruiting into the photostations. A combination of at least three factors have contributed to changes in the benthic community observed during this investigation: (1) the massive coral bleaching event in the fall of 1998 which disproportionately affected Montastrea spp.; (2) a category 5 hurricane; and (3) increased anthropogenic stress in the form of sedimentation and nutrient enrichment as the result of new and unregulated development.

This study measured certain biological characteristics (zooxanthellae concentrations and diameters, pigment concentrations, and colony color) of Montastrea cavernosa from the outer reef (16.8 - 26.5 m) in Broward County, FL in response to reduced light and elevated temperature stresses. The low light treatment simulated a lowering of light in the summertime (possibly associated with a turbidity increase from an event such as a hurricane, ship grounding, or dredging). The high temperature treatment was set at the maximum expected anomaly (3°C above the average summer maximum) to simulate the effect of warmer than normal seawater. The combination treatment tested for synergistic effects. Zooxanthellae concentrations and cell sizes were measured microscopically. Photosynthetic pigment (chlorophyll a, chlorophyll c, peridinin, diadinoxanthin, and β-carotene) concentrations were measured by high performance liquid chromatography. Significant decreases were found in zooxanthellae and pigment concentrations due to the elevated temperature treatments. No significant changes in zooxanthellae and pigment concentrations were observed due to the low light conditions or due to interactions from the combined stresses. Zooxanthellae cell sizes-did not change significantly, regardless of treatment. Coral color change, "bleaching", was measured by a novel RGB color analysis method. Significant decreases were found in coral color due to the elevated temperature treatments. No significant changes were observed due to the low light conditions or due to interactions from the combined stresses. These results agreed with those for zooxanthellae and pigment concentrations, indicating that RGB color analysis was an acceptable, non-destructive method to quantify coral bleaching. RGB color analysis has benefits over qualitative visual observations that include (i) the reproducibility of color values despite differences in color perception and changes in ambient lighting and (ii) comparisons of color change within variable-colored coral species (e.g. Montastrea cavernosa) and between two or more species of different colors (e.g. Acropora cervicornis and Siderastrea radians).

It was the focus of this manuscript to use passive optical remote sensing to classify the benthic facies of a large study area such as the southeastern Arabian Gulf. Landsat TM and Quickbird sensors were also evaluated for the determination of benthic facies. Spatial distributions were further examined from the classified image to study facies patterns. It was found that Landsat TM sensors could be used to accurately classify benthos of a large study area such as the southeastern Arabian Gulf if sufficient ground control data was available. This was determined by using both the unsupervised and supervised classification techniques in the ENVI 4.1 program. When discussing the issue of scale in relevance to classification for small areas considered in isolation (i.e. Butina Island), the Landsat TM sensor returned classification results comparable to those obtained with a higher spatial resolution (Quickbird sensors). By using the classification results from the southeastern Arabian Gulf, the patch frequency of the facies concluded that patch frequency and area were inversely related, with smaller areas being more common and larger areas rare. The data showed a linear relationship on log-log plots and therefore could be termed a power function. Due to the linear relationship, perhaps patch frequency and area follow a power function.

Novel predator introductions are thought to have a significant impact on the survival and fitness of naïve prey, especially in freshwater systems. The ability of prey to recognize and respond appropriately to these novel threats may depend on the prey’s use of general or specific cues to detect predation threats. We used laboratory behavioral experiments to examine the ability of three native Everglades prey species (Eastern mosquitofish, Gambusia holbrooki, flagfish, Jordanella floridae, and riverine grass shrimp, Palaemonetes paludosus) to respond to the presence and to the sensory cues of a native predator (warmouth, Lepomis gulosus) and those of a recently introduced non-native predator (African jewelfish, Hemichromis letourneuxi). Specifically we examined: (1) the predation threat of the non-native jewelfish (2) the combined mortality affect of the native and non-native predator (3) the ability of the prey to respond the non-native predator and (4) the prey species use of chemical and visual cues to detect predation threats. Despite its novelty, our results indicated that the native warmouth and non-native jewelfish had similar predatory effects, although these effects may be somewhat prey specific. For mosquitofish, the novel predator represented less of a predation risk, while predation rates were similar for flagfish and grass shrimp. All three prey species showed surprisingly strong responses to the non-native jewelfish, which were comparable to the responses exhibited to the native predator. This would suggest that prey are relying on general cues for predator detection. However, during the predator cue experiments two of the naïve prey species, mosquitofish and flagfish, were able to respond to the specific chemical cues of the non-native predator with an equal intensity to that of the native predator. These broad response may indicate that some native Everglades prey have a greater behavioral plasticity or more experience with novel predators that allow them to detect and respond to a novel predation threat.

A series of mass strandings caused by a morbilli virus epizootic in 1987/88 were estimated to have caused the mortality of between 10 and 50 percent of the Atlantic bottlenose dolphin, Tursiops truncatus, population along the Atlantic coast of the United States. In addition, the stranding provided further evidence of two distinct stocks of dolphins, one inshore and one offshore. Subsequently the coastal stock of bottlenose dolphins was declared depleted under the Marine Mammal Protection Act and holds that status today. From April 1982 to August 1984 aerial sightings were recorded seasonally along the continental shelf from Cape Hatteras, NC to Key West, FL. These data were collected in conjunction with the Southeast Turtle Surveys (SETS) conducted by the National Marine Fisheries Service along random aerial line transects. These datasets were analyzed using the computer program Distance v5.0 to determine population density and abundance across locations, seasons, and years. Covariates, including temperature and sea state, which may affect the ability of observers to sight the dolphins, were considered. Numbers were pooled to determine population abundance prior to the 1987 mass stranding event to determine density change, if any. To visually demonstrate density the sightings and tracklines were mapped using the computer program Global Mapper v7.0. Results demonstrate the dolphins follow similar migratory patterns as currently observed including a shift of animals north in the summer and south \n the winter. The total abundance of dolphins in this area in the 1980's was significantly (p = 0.0014) less than that found in the 2002 dolphin surveys with a total number in the summer of the early 1980's of 10,102 (CV = 0.1445) and a current estimate of21,527 (CV = 0.2427). In 1995 the Southeast cetacean aerial survey, a replicate study of SETS, was completed in the winter and found 20,005 individuals, a significantly (p = 0.0456) larger number than estimated in SETS. These abundance estimates indicate that the mortality caused by the morbillivirus in 1987/88 did not significantly decrease the overall population of bottlenose dolphins in United States' waters south of Cape Hatteras, NC.

The southeastern United States continental shelf supports a diverse community of recreationally and commercially important reef fish. However, little is known about the reef fish community associated with the shelf edge between the depths of 50 and 120m. Offshore of Broward County, Florida, the continental shelf is narrow and appears to provide limited natural fish habitat. Numerous artificial vessel-reefs have been deployed throughout this region to enhance local recreational fisheries. The reef fish assemblage has not been adequately described at these vessel-reefs and interactions between fish assemblages on vessel-reefs and those on neighboring natural habitat are unclear. Remotely operated vehicle (ROV) surveys, were conducted at three separate vessel-reefs along with several regions of neighboring natural substrate to determine the reef fish assemblage, species richness, and abundances. During two years of study, 785 minutes of video were recorded from vessel-reefs along with 488 minutes from natural substrate. ROV surveys along the continental shelf between 50 and 120m depths revealed no regions of exposed hardbottom with vertical relief greater than one meter. Twenty-seven different species were observed on natural substrate transects with an average of 32.0 (+/- 39.2 SD) fish per survey hour. Manmade artifacts, such as tires, were commonly observed during surveys and harbored a large percentage of the fish recorded along the continental shelf. Bank sea bass, Centropristis ocyurus, and tattler bass, Serranus phoebe, were common among tires along with occasional juvenile snowy groupers, Epinephelus niveatus. At a depth of 110m, grey tilefish, Caulolatilus microps, and tilefish burrows were observed. A majority (66%) of species observed has been recorded at depths less than 30m in Broward County, however trophic structure differs between depths. Planktivores, benthic carnivores, and piscivores numerically dominate deep regions, while herbivores and omnivores were absent. Fifty-three different fish species were observed on three vessel-reefs, Bill Boyd, Caicos Express, and Papa’s Reef, at depths between 50 and 120m. Vessel-reefs had a significantly higher species richness (21.4 +/- 4.1 SD) and abundance (255.1 +/-250.0 SD minus anthiine fishes) of fish observed per hour of video compared to natural substrate surveys (p < 0.01 and p = 0.01 respectively, T-test). Anthiine fishes, numerically dominated vessel-reefs, with several thousand (2277.8 +/-1735.9, during 2005/06) observed on each survey. Seventy percent of total species recorded are typically found as adults in less than 30m depth in Broward County. Most of these fishes were predators that were not found on the natural substrate between 50 and 120m depths during this study. Several deeper reef fish (ie. fishes that spend a majority of their adult life at depths greater than 50m) were recorded on vessel-reefs. Spotfin hogfish Bodianus pulchellus, replaced its shallow water congener spanish hogfish, B. rufus. Bank butterflyfish, Prognathodes aya were more common than reef butterflyfish, Chaetodon sedentarius. Juvenile deep reef serranids, speckled hind, Epinephelus drummondhayi and snowy grouper, Epinephelus niveatus were observed. Two deep reef lutjanids were also recorded, blackfin snapper, Lutjanus buccanella and vermilion snapper, Rhomboplites aurorubens. A Bray Curtis MDS plot of similarity indices suggested some differences in assemblage structure between the vessel-reefs (2D stress = 0.18). These differences were due to a few species. The Caicos Express, located in the shallowest depth (74m), had a large school (300+ fish) of tomtates, Haemulon aurolineatum, associated with it, while the Bill Boyd, located in 82m depth, typically had a large mixed school of amberjack, Seriola dumerili and almaco jack, Seriola rivoliana around its more extensive superstructure. Papa’s Reef had two Sciaenids, black bat drum, Pareques iwamotoi and cubbyu, Pareques umbrosus that were uncommon on other vessel-reefs. Vessel-reefs were sampled throughout the year and there was no significant change in species richness or abundance with the change of seasons ( p = 0.922 and p = 0.419 respectively, ANOVA). The deep reef fish community on small artificial structures as well as vessel-reefs was more similar to communities reported from equivocal habitats at the same depth hundreds of kilometers away than with the nearby outer reef tract in 30m depth.