Hypoxia in coastal estuaries is a topic of increasing concern, as the magnitude and frequency of hypoxic events have increased over the past several decades. These hypoxic events are highly detrimental to the coastal biota, particulary fish. The hypoxia-inducible factor 1α (HIF-1α) protein was used as a candidate biomarker for deciphering exposure of fish to hypoxic events. In chapter one, Spot (Leiostomus xanthurus) were exposed to three treatment groups of DO (means 7.32 ± 0.18, 5.15 ± .37, and 2.57 ± 0.01 mg Lˉ¹ DO) and sampled (n = 5) at time zero, 36 and 72-h for each treatment. The results of the laboratory trials suggested that duration had a significant effect (F = 28.9, p < .001) on concentration of HIF-1α protein, however, the DO treatment group did not have a significant effect (F = .739, p = .546) on the concentration of HIF-1α protein. L. xanthurus were also analyzed for HIF-1α from field sites of varying DO concentrations (7.0, 5.2, 4.8, and 3.3 mg Lˉ¹ DO), with no significant differences (F = 1.621, p = .208) between sample sites, and with a negative relationship between DO and HIF-1α protein (p = .197) from these sites. Leiostomus xanthurus were exposed to either constant or diel-cycling hypoxia, and HIF-1α expression was compared to normoxic control over three days. The results indicated that HIF-1α protein significantly (p = 0.02) increased in muscle tissue after three days exposure to both constant and a simulated diel-cycling hypoxic event in a laboratory setting when compared to normoxic control animals. It was also found that body mass (measured in wet weight, grams) was a significant covariate for the concentration of HIF-1α produced under normoxia (p = 0.04) and constant hypoxia (p = 0.03), but did not affect the diel-cycling (p = 0.83) groups, suggesting that body mass is a confounding factor when measuring HIF-1α. The correlation of HIF-1α with body mass is likely due to the different tolerances to hypoxia between small and large young-of-year L. xanthurus, an effect that was possibly overshadowed by the acclimation response under diel-cycling hypoxia.

A gopher tortoise population on the campus of University of North Florida is part of an ongoing study initiated during the early 1990s, and this project presents data on this population collected during the 2009-2011 field seasons. The project has three major objectives: 1) measure population demographics including density and structure to assess long-term viability and recruitment, 2) evaluate decadal growth rates of individuals by comparing measurements of tortoises captured and marked in the 1990-1994 study done at the same site with those tortoises recaptured during the current study, and 3) assess the effect of prescribed burning on vegetation. In total, 141 individuals were caught from 2009-2011: 32 adult females, 28 adult males and 17 young adults, 43 juveniles and 21 hatchlings. Of these, 39 are recaptures from the research performed in the early 1990s. Adult burrow aprons were probed using a wire survey flag in an attempt to locate nests. In 2010 we found two intact nests with this technique and recorded two other depredated nests that were unassociated with any burrow. In 2011 we found one nest and a clutch that was laid on the ground’s surface. Four 100m transects were established before prescribed burning began. Vegetation analyses were done bi-monthly and all plants were recorded as well as their percent of each plot. The most abundant plant was milkpea. Preliminary analysis of postburn response has indicated increased groundcover in all burned transects.

Understanding the life history of marine wildlife is essential for the management of both commercial and recreational fisheries. Bonnetheads (Sphyrna tiburo) are a component of the small coastal shark (SCS) fishery complex, and are caught regularly in both types of fisheries. Despite being well studied in the Gulf of Mexico, little is known about bonnetheads from the U.S. Atlantic coast. The goal of the first component of this study was to provide new, key information on their life history to improve management of U.S. Atlantic populations, particularly by identifying reproductive seasonality, periodicity and fecundity. This was accomplished by examining sexually mature male and female bonnetheads, collected monthly (2012-2014) from South Carolina, Georgia, and Florida waters, and monitoring changes in reproductive tract morphology. Changes reflected a seasonal reproductive cycle with an annual breeding periodicity. Histology was used to confirm events and identify other important periods in the reproductive cycle, such as sperm storage in females. Overall, Atlantic coast bonnetheads were found to exhibit reproductive patterns similar to those reported in the Gulf with slight temporal shifts in the time of mating and ovulation and slightly lower fecundity ranging between 1 and 12 with an average (±SE) of 7±3.8. Additionally, the second component of this study aimed to understand gonadal sex hormone regulation in S. tiburo reproduction with a particular focus on female sperm storage. Circulating plasma sex hormones increased in association with specific reproductive events. Plasma 17β-estradiol and testosterone concentrations increased during sperm storage, whereas progesterone levels increased near the end of this stage. Immunocytochemical analysis of androgen, estrogen, and progesterone receptors in the oviducal viii gland, the organ that stores sperm in female bonnetheads, demonstrated that epithelial cells of sperm storage tubules and spermatozoa itself are direct targets for these hormones, playing a role in regulating this poorly understood process.

Sharks often bioaccumulate mercury (Hg) concentrations in their muscle to levels that threaten the health of human consumers. However, few published studies have examined if the high Hg levels seen in shark muscle also occur in the shark brain, or if Hg accumulation affects shark neurophysiology. Therefore, this study examined if shark brains accumulate significant levels of Hg, if Hg accumulation occurs in certain subcomponents of the brain, and if Hg accumulation is associated with oxidative stress effects on the shark central nervous system, with special focus on the Atlantic sharpnose shark (Rhizoprionodon terraenovae). Sharks were collected along the U.S. Southeastern coast throughout most of the shark’s geographical range. Known biomarkers of Hg-induced neurological effects (markers of glial cell damage, S100b, and markers of oxidative stress) in the shark cerebrospinal fluid were examined. Brain Hg levels were correlated with muscle Hg levels, but were significantly lower and did not exceed most known thresholds for neurological effects, suggesting limited potential for such responses. Data on known biomarkers of Hg-induced neurological effects support this premise, because they were not correlated with brain Hg levels. Organic methylmercury did not compose of a high percentage of the total mercury in the brain, indicating demethylation of Hg is occurring in the brain. Higher Hg levels were measured in the forebrain of the shark in comparison with the midbrain and hindbrain, but levels in both were below threshold levels for effects. This study is the first to demonstrate the correlation and significant difference of Hg in the brain and muscle of sharks, and it identifies significantly higher Hg levels in the forebrain; making this study one of the most extensive analysis of Hg in a single shark species.

The goal of this study was to examine the potential health effects of organochlorine (OC) and polycyclic aromatic hydrocarbon (PAH) exposure on Atlantic stingray populations in Florida’s St. Johns River (SJR). Special emphasis was placed on identifying OC- and/or PAH-related effects in stingrays from areas of the lower (LSJR) and middle (MSJR) basins shown to possess elevated levels of these compounds, as well as characterizing baseline levels of pollutant exposure in the SJR shipping channel, which may be subjected to dredging in the near future, potentially resuspending and redistributing contaminated sediments and increasing pollutant-associated effects. To accomplish this, we measured OC and PAH biomarker levels in stingrays collected from contaminated and reference sites. We specifically examined the phase I detoxification enzyme, cytochrome P4501a1 (CYP1a1); the phase II detoxification enzymes, glutathione-S-transferase (GST) and uridine 5’-diphosphate glucuronosyltransferase (UGT); fluorescent aromatic compounds, PAH bile metabolites; and lipid peroxidation (LPO), cell membrane damage. Biomarker values collected between 2014 and 2016 were compared by site. Detoxification enzyme activity and LPO values from individuals collected from the three MSJR lakes between 2002 and 2005 were compared to those collected between 2014 and 2016. The data suggested that biomarker values from the SJR were variable, with elevated levels from Lake Jesup. Compared to reference estuaries, the LSJR has low biomarker values. This indicates that residing in certain portions of the MSJR is detrimental to stingray health, while residing in the LSJR is not. Lake Monroe and Lake George biomarker levels indicated reduced contaminant input over time, whereas Lake Jesup biomarker levels suggested the opposite. This study has developed a baseline for biomarker levels in the LSJR, allowing for the identification of dredging-induced changes to the system, and has identified temporal changes in biomarker levels from three MSJR lakes.

Klebsiella pneumoniae is an opportunistic pathogen responsible for lobar pneumoniae, liver abscess, and septicemia. Clinical isolates are found to be extended spectrum beta lactamase positive with differential expression of the two classical porins, OmpK35 and OmpK36. Porin loss is associated with increased minimum inhibitory concentrations of beta lactam, cephalosporin, and carbapenem antibiotics that target the peptidoglycan. However, little is known about how porin loss affects other aspects of the cell envelope. The focus of this study was to characterize clinical isolates exhibiting differential porin expression and determine if the cumulative changes altered the resistance to phagocytosis by macrophages. The results support the hypothesis that porin loss significantly impacts the overall cell envelope composition, which in turn alters interactions with macrophages.

In animals, the accepted model of carbohydrate digestion and absorption involves reduction of disaccharides into the simple sugars glucose, fructose and galactose. Previous studies have shown the presence of disaccharides maltose and trehalose in the blood of several crab species, the crayfish and the American lobster. In 2011, a gene for a distinct disaccharide sucrose transporter (SCRT) was first found in Drosophila melanogaster and characterized using a yeast expression system. The purpose of the current study was to identify and characterize a putative disaccharide transporter analog in crustaceans using the American lobster, Homarus americanus. Brush border membrane vesicles purified from the hepatopancreas were utilized. After identification of a sucrose transporter in the brush border membrane of the hepatopancreas, transport kinetics experiments were used to characterize it using 14C radio-labeled sucrose and a Millipore filter isolation technique. Lack of glycyl-sarcosine inhibition of sucrose uptake into vesicles indicated that the highly non-specific dipeptide transporter PEPT1 was not the functional transporter of sucrose. A more acidic pH of 4 was shown to drive sucrose transport in the absence of sodium. Sodium was then shown to also significantly stimulate sucrose uptake, which resulted in an overshoot at 1 minute over a hyperbolic potassium uptake curve, suggesting that both sodium and acidic pH were capable of driving disaccharide transport. Experiments that used a variety of monosaccharides and polysaccharides indicated that the disaccharides maltose and trehalose were the only sugars to significantly inhibit carrier-mediated sucrose transport (maltose P = 0.017, trehalose P = 0.023 using a one-way ANOVA) (Km = 0.1951 ± 0.0630 mM sucrose, Jmax = 0.5884 ± 0.0823 nmol/mg protein x 1 minute), suggesting specificity of the transporter. Sucrose in the presence of 20 mM maltose had a Km of 0.5847 ± 0.1782 mM sucrose (P = 0.030) and a Jmax of 0.6536 ± 0.1238 nmol/mg protein x 1 minute (P = 0.006). ANOVA P-values indicate the difference between the sucrose control curve and the maltose curve. The highly significant reduction between the Km values of the control sucrose curve and the maltose curve suggests competitive inhibition between the two sugars. These two disaccharides could utilize the same transporter, and are appropriate for the physiology of the animal in this case, as lobsters commonly digest glycogen and chitin, polymers of maltose and trehalose, respectively. These findings suggest there is a brush-border proton-, or sodium-dependent, hepatopancreatic carrier process, shared by sucrose, maltose, and trehalose, that may function to absorb disaccharides that occur from digestion of naturally-occurring dietary constituents.

Based on recognized life history traits and ecology, zoos strive to house their gorillas (Gorilla gorilla gorilla) in mixed-sex groups with one mature male or silverback, multiple females, and their offspring. However, successful captive breeding programs and a nearly 50:50 birth sex ratio has created the need to house surplus males in solitary conditions or all-male groups. It is commonly believed that male western gorillas will not tolerate one another in the presence of females; however, multi-male, mixed-sex groups have been observed in the wild. For this reason, some zoos have begun experimenting with this scenario. At the time of data collection, only four of the 51 institutions housing gorillas in the North American Species Survival Plan® population housed multi-male, mixed sex groups. Chapter one documents the activity budgets of two of these multi-male groups and compares them to those of two traditional family troops. Overall behavior repertoire was similar between group type, though more locomoting and aberrant behaviors were exhibited by individuals in the multi-silverback groups. Interaction between the silverbacks varied greatly between the multi-male groups which suggests there could be multiple models of success for these groups. However, further insight is needed to determine why some multi-male groups are successful while others are not. Therefore, the second chapter outlines the results of a multi-institutional survey which covered the recent history of multi-male, mixed-sex groups in North American zoos. The goal of the survey was to determine potential factors associated with silverback compatibility. Results indicate that there is an association between successful multi-male, mixed-sex groups and some life history factors including the relatedness of the males, their rearing histories, and the time at which they were introduced. This research offers insight into a potential gorilla social assemblage that has been underutilized in zoo settings.

From 2008 to 2012, the total U.S. commercial landings of blue crabs (Callinectes sapidus Rathbun, 1896) averaged over 173 million lbs. Chesapeake Bay and its tributaries are important contributors to this fishery, providing greater than 30% of national commercial landings annually. In Chesapeake Bay, C. sapidus exhibits a complex life cycle in which mated females migrate to the saline waters of the Bay mouth to spawn. During migration, females can traverse multiple management jurisdictions, complicating effective management of this important fishery. Sustained declines in harvest have led to management strategies focused on protecting the female spawning stock in an attempt to enhance recruitment back into the Bay. This study presents the results of a broad scale mark-recapture study (n=7,072) in 11 Chesapeake Bay subestuaries and one coastal embayment, designed to track female migration and quantify spatial variation in exploitation rates of mature female blue crabs. Tagging was conducted in fall 2014 (September and October), when most females have matured and begin to migrate to the spawning grounds, and in summer 2015 (July), when additional females mature and migrate to the spawning grounds. Approximately 8.1% of tagged females were recaptured within one year of release. Overall, the exploitation rate of the 2015 blue crab spawning stock in Chesapeake Bay was 10.5%; however exploitation varied widely among systems (4.0-28.5%). This estimate is below both the management target and threshold exploitation rates and the population grew in subsequent years, suggesting recruitment overfishing of blue crabs was not occurring in Chesapeake Bay at this time.

The St. Johns River (SJR; Jacksonville, FL, USA) is a large, brackish, estuarine system characterized by considerable anthropogenic pollution, recurrent harmful algal blooms (HABs), and diverse toxin-producing cyanobacteria. The most prevalent toxins in SJR water samples are microcystins/nodularins (MCs/NODs). Additionally, the SJR provides critical habitat for a genetically and behaviorally distinct estuarine community of bottlenose dolphins (Tursiops truncatus) that routinely uses and strands in low mesohaline and oligohaline areas of the river. This population has been subject to two unusual mortality events (UME) since 2010 and has since been described as having substantial declines in population health, characterized by widespread dermatitis and emaciation. Additionally, three dolphins have been recovered from low salinity habitats with epidermal algal mats. Because dolphin illness and strandings overlapped temporally and spatially with confirmed cyanobacterial blooms in the SJR, there is concern that estuarine dolphin health may be declining due to exposure to toxic cyanobacteria and HAB events. Specific to this study, the SJR estuarine community was considered a high-risk group for cyanotoxin exposure in relation to coastal animals. This study analyzed all available hepatic tissues for estuarine dolphins, and used samples from coastal individuals that stranded outside of the known cyanotoxin bloom season as controls. Three analytical methods were used to determine MCs/NODs presence in dolphin liver and epidermal algal mat samples. An Adda ELISA and LC-MS/MS were used to determine free MCs/NODs presence while the MMPB technique was used to determine total (bound and free) concentrations and as confirmatory analyses. ELISA analyses produced high values that were not supported by concurrent LC-MS/MS or MMPB analyses, indicative of false positives. MMPB testing resulted in low-level total MCs/NODs detection in some specimens. Results indicate that both estuarine and coastal dolphins are exposed to MCs/NODs, with potential toxic and immune health impacts.