The Deepwater Horizon blowout occurred on April 20th, 2010, releasing 4.9 million barrels of Louisiana crude oil into the Gulf of Mexico (GoM). Subsequent to the Deepwater Horizon blowout, sediment cores revealed oil on the northern GoM seafloor and abnormal skin lesions were seen in GoM fishes. Exposure to polycyclic aromatic hydrocarbons (PAHs), a component of crude oil, in fish has been associated with many sublethal effects, including cancer and population-level effects. Using a biomarker of exposure to PAHs, this thesis evaluates inter-species, temporal and spatial differences in exposure to hydrocarbon contamination between three species of fish with varying levels of association with the sediment, that were potentially exposed to Deepwater Horizon crude oil: golden tilefish (Lopholatilus chamaeleonticeps), king snake eel (Ophichthus rex) and red snapper (Lutjanus campechanus), and examines patterns in these data using life history, behavior and environmental data. In 2011, 2012 and 2013, bile samples and biometric data were collected from fish via demersal longlining and bile was analyzed for three PAHs, naphthalene, phenanthrene and benzo[a]pyrene and their metabolites, using high performance liquid chromatography with fluorescence detection (HPLC-F). Bile of golden tilefish had significantly higher concentrations of naphthalene and phenanthrene metabolites, compared to red snapper and king snake eel. For biliary naphthalene metabolites, golden tilefish had an average concentration of 240 ug g-1, compared to 61 ug g-1 for red snapper and 38 ug g-1 for king snake eel, for the year 2012. Biliary naphthalene metabolite concentration has decreased 8% in golden tilefish samples, between 2012 and 2013, indicating continuous exposure to petrogenic pollution, while naphthalene metabolites decreased 49% over time for red snapper and 37% for king snake eel, indicating episodic exposure to elevated petrogenic pollution prior to 2011. The concentration of naphthalene metabolites measured in golden tilefish in this study are some of the highest concentrations measured in the GoM and internationally, while naphthalene metabolite concentrations for red snapper and king snake eel are similar to 1990's GoM data. In contrast, concentrations of benzo[a]pyrene metabolites were statistically similar for all three species, suggesting a difference in the disposition of or exposure to benzo[a]pyrene contamination. Concentrations of benzo[a]pyrene metabolites are relatively low when compared to other GoM and international data, for all three species. This study has identified a species of GoM fish, golden tilefish, that is exposed to a present-day source of petrogenic PAH pollution and certain fish species that were episodically exposed, in the years following the Deepwater Horizon blowout. With residual Deepwater Horizon oil still found in GoM sediments, coastal marshes and beaches, there is a need to identify these chronic exposures to persistent PAH pollution, monitor PAH concentrations in over time and evaluate the resulting sublethal effects to better understand the impacts of the Deepwater Horizon blowout on marine resources such as GoM fisheries.

Cytokines are pleiotropic and redundant signaling molecules that govern the inflammatory response and immunity, a critical ecological parameter for organism success and population growth. Produced at the site of injury or pathogen intrusion by a variety of cell types, cytokines mediate cell-signaling in either an autocrine or paracrine manner. The type and magnitude of the cytokine milieu produced subsequently dictates the strength and form of immune response. As the most diverse vertebrate group, with a high sensitivity to contaminants, fish represent an important foci for the evaluation of immune system evolution, function, and alteration upon toxicant exposure. While many cytokines have been identified in teleosts, primary study has been limited to model species (e.g. zebrafish and fugu). However, evidence exists for several variations of cytokine genes within taxa, underscoring the need for species-specific evaluation. In this study, two pro-inflammatory cytokines (IL-1β and TNFα ), one chemokine (IL-8), and one anti-inflammatory cytokine (IL-10) were cloned, sequenced, and characterized for the first time in two commercially relevant Perciformes in the Gulf of Mexico, golden tilefish (Lopholatilus chamaeleonticeps) and red snapper (Lutjanus campechanus). The complete amino acid sequence was obtained and confirmed for IL-β and IL-8 from golden tilefish and for IL-8, IL-10, and TNFα from red snapper, with partial sequences obtained for the remaining proteins. The results indicate high homology among Perciformes for all cytokines studied, but divergence with other teleost orders, and low conservation when compared to birds, amphibians, and mammals. The sequences will be used to create a multi-plexed antibody-based assay for the routine detection of cytokines in teleost serum. This would allow the biochemical response to fish health challenges, such as oil spills and other contamination events, to be monitored at the protein level, building upon the current regime of genetic biomarkers. Thus, this work will aid in the understanding of how oil spills and other contamination events may alter the immune response in fishes.