Florida’s recreational bonefish fishery generates substantial economic benefits to the region; however, the resource has never been adequately assessed to determine standard benchmarks for sustainability. The situation offered a unique opportunity to address unresolved issues in sustainability for a valuable recreational fishery that is almost exclusively catch and release. The goal of this dissertation was three-fold: (1) to develop a comprehensive framework for conducting rigorous stock assessments on recreational catch-and-release fisheries; (2) to apply these methods to the Florida bonefish fishery to compare results against internationally-recognized sustainable fishery benchmarks; and, (3) provide recommendations for longer-term assessment strategies and management efforts. Due to the dearth of available bonefish information, existing literature were synthesized and new quantitative data and models concerning bonefish demographics (i.e. growth, survivorship) and population dynamics were developed. Data for age-and-growth were collected with a focus on both small (< 100 mm FL) and large (>650 mm FL) bonefish which had been under-sampled in previous research. A two-stage growth model was developed that allowed predictions of size-at-age over the complete life history of the species. Evidence from multiple analyses suggested a single species of bonefish in the Florida fishery. A mail survey of bonefish captains (guides) acquired baseline statistics on the south Florida bonefish fishery. Fleet fishing effort is mostly concentrated in the northern Florida Keys (Biscayne Bay to Islamorada) and reflects to some extent bonefish spatial population abundance. The majority of the respondents indicated the stock had declined over the past few decades. A sized-based mortality estimator was used to determine mortality. Changes in current population size from 2003-2010 were determined from a visual survey. Historical stock size was inferred from a relative abundance index from standardized tournament catch rates. Annual trends of the mortality estimates implied a stable population that is not declining which contrasts with the index of abundance and visual survey results. Both the index of abundance and visual survey displayed overall declining trends in recent years. Bonefish movements were determined from anchor tag and acoustic telemetry. Anchor tagging data were analyzed to evaluate movements, stock size structure and mortality. Results revealed no significant relationships between distance moved and days at large or days at large and length at tagging; however, significant individual movements (>100 kilometers) were recorded. Use of acoustic telemetry showed frequent movements around the barrier islands, schooling behavior, and a possible spawning effect with movements to offshore reef habitats. Stock status was addressed with two different classes of assessment models: REEFS, a length-based model which estimated the stock as moderately exploited with the current fishing mortality rate less than the maximum sustainable yield fishing mortality rate; and a “catch-free” age-structured model which indicated a large stock decline over the past 40 years with the stock currently bordering an overfished benchmark. The age-structured model was assumed to be the most robust method because it incorporated the majority of the research data (age and growth, selectivity, mortality, visual survey, CPUE standardization, vessel effort). In conclusion, the stock’s productivity has been significantly reduced over the past 50 years due to fishing, but also degradation of key prey populations, habitats, and water quality, resulting in a current bonefish population that is bordering an overfished state. Recommendations are provided for improving future stock assessments and management approaches. The assessment framework and quantitative methods and models developed here are broadly applicable to bonefish stocks around the world.

Groupers (Epinephelidae: Epinephelinae) are apex predators within many reef communities worldwide. Grouper landings contribute significantly to global fisheries, and many populations are suffering from unsustainable levels of exploitation. The large size, site specificity and catchability of most groupers increase susceptibility to fishing pressure, and a large number of grouper species throughout the world are currently overfished. Multiple species are listed as endangered or threatened, and many have suffered local extirpations across their range. Removal of these upper level predators can significantly alter community structure and result in second order effects that may have critical ecological implications. The economic and ecological value of groupers is significant, and data regarding the abundance, habitat and behavior of these exploited species are necessary in order to implement realistic and effective management strategies. Atlantic Goliath Grouper (Epinephelus itajara) historically occurred in tropical and subtropical waters from the west coast of Africa to the east coast of Florida, south to Brazil, and throughout the Caribbean Sea and Gulf of Mexico. As one of the world's largest groupers, individuals are known to reach at least 37 years of age, and may grow to sizes exceeding 2.5 meters and 400 kilograms. The life history and behavioral characteristics of this species amplify vulnerability to exploitation, and Atlantic Goliath Grouper harvest was banned in U.S. waters in 1990 after a noted sharp decline in population numbers. The species has responded encouragingly to protective measures; however, the population's recovery and present status with U.S. waters should be thoroughly evaluated before altering regulatory guidelines. Traditional fishery-dependent data are not available (i.e., landings data); thus estimates of population demographics and recovery are dependent upon directed, fishery independent research efforts. It was the goal of this project to provide information regarding demographics, movement patterns, effects of catch and release angling, and feeding behavior of Atlantic Goliath Grouper within the central eastern Gulf of Mexico. The majority of research involving Atlantic Goliath Grouper began after the stock was already overfished, resulting in the absence of an existing "baseline" with which to compare current population parameters. Replication of visual surveys over a range of depths and habitat types provided an index of abundance for specific sites, and allowed for quantification of the size distribution of individuals. Atlantic Goliath Grouper were most abundant at high relief, high volume artificial reefs within the study area, and the majority of individuals observed were 80 - 160 cm in total length. Knowledge of fish movement, behavior and habitat associations has been used to exploit many species of fish; thus, this knowledge is critical for the creation of regulatory guidelines regarding conservation. Protection from harvest does not immediately imply that fishing mortality is negligible. As opportunistic ambush predators, Atlantic Goliath Grouper are relatively easy to catch on hook and line, and the species is often targeted for sport or caught incidentally during angling efforts for other reef fish species. Acoustic tracking allowed for continuous monitoring of individuals for several years after catch and release events. Barotrauma severity increased with capture depth, but immediate mortality was not observed during this study. Additionally, the length of total monitoring period was not affected by the severity of barotrauma, which suggests that with proper handling, Atlantic Goliath Grouper are not subject to high levels of release mortality in the study area (at depths < 40 m). However, strong site fidelity of Atlantic Goliath Grouper to artificial reefs increases susceptibility to fishing pressure and amplifies interactions with anglers, so the chronic effects of repeated capture remain unclear. Description and quantification of goliath grouper feeding behavior may allow for innovative suggestions to decrease the probability of catch and release mortality, and potentially offer new tactics to reduce opportunistic predation upon hooked fish. Kinematic analysis of Atlantic Goliath Grouper feeding sequences demonstrated that they are capable of modulating feeding behavior based upon prey activity level and position within the water column. Individuals exhibited larger maximum gapes and more rapid feeding sequences when presented with mobile live food. Immobile (dead) food was primarily consumed through suction, and strikes upon these items were characterized by slower, closer approaches, smaller maximum gapes and longer bite durations. It is hopeful that the information presented herein will provide insight regarding the ecology of Atlantic Goliath Grouper and can be applied to future management efforts involving this protected species.

This thesis had two overriding aims. The first was to describe the biology of Samson Fish Seriola hippos and therefore extend the knowledge and understanding of the genus Seriola. The second was to uses these data to develop strategies to better manage the fishery and, if appropriate, develop catch-and-release protocols for the S. hippos sportfishery. Trends exhibited by marginal increment analysis in the opaque zones of sectioned S. hippos otoliths, together with an otolith of a recaptured calcein injected fish, demonstrated that these opaque zones represent annual features. Thus, as with some other members of the genus, the number of opaque zones in sectioned otoliths of S. hippos are appropriate for determining age and growth parameters of this species. Seriola hippos displayed similar growth trajectories to other members of the genus. Early growth in S. hippos is rapid with this species reaching minimum legal length for retention (MML) of 600mm TL within the second year of life. After the first 5 years of life growth rates of each sex differ, with females growing faster and reaching a larger size at age than males. Thus, by 10, 15 and 20 years of age, the predicted fork lengths (and weights) for females were 1088 (17 kg), 1221 (24 kg) and 1311 mm (30 kg), respectively, compared with 1035 (15 kg), 1124 (19 kg) and 1167 mm (21 kg), respectively for males. Despite these differences, female and male S. hippos attained similar maximum age, i.e. 29 (1470 mm FL) and 28 years (1280 mm FL), respectively. The maximum age determined for S. hippos is greater than that recorded for any other Seriola spp. The largest female and male S. hippos recorded during this study were encountered during the tagging component and had fork lengths of 1600 mm and 1380 mm, respectively. Seriola hippos has a protracted spawning period, ca four months, which starts in late spring and continues through summer into early autumn during which time many individuals engage in large spawning aggregations on the lower west coast of Australia. The length at which 50 % of the females in the population reached maturity was 831 mm FL (888 mm TL) and approximately 4 years of age, whilst all females over 950 mm FL were mature. Whilst aggregated for spawning S. hippos ceases feeding, however, during the non-spawning period this species can best be described as an opportunistic carnivore which feeds on a variety of pelagic and demersal prey. This study has greatly increased our understanding of S. hippos movement on the west and south coasts of Australia and has documented, for the first time, the migratory behaviour of a carangid in these waters. Many S. hippos individuals undertake long distance migrations to join spawning aggregation sites near Rottnest Island. Individuals tagged at these aggregation sites where recaptured throughout this species distribution along the south coast of Australia, some after travelling distances of over 2400 km. Many S. hippos individuals displayed strong temporal and spatial spawning ground fidelity as numerous fish released at the spawning aggregations were recaptured at the exact same spawning site at similar times in subsequent years. Tagging data suggest that on the completion of spawning S. hippos individuals return to a resident location and remain in that general vicinity over the winter months. This study has developed a hypothesis describing larval dispersal associated with the S. hippos spawning behaviour exhibited near Rottnest Island. It is proposed that variations in the prevailing ocean currents, at this important spawning location throughout the protracted spawning period, leads to high intra and inter-annual variation in larval distribution and survival. The affect of this variation on the evolution of the spawning and migratory behaviour displayed by S. hippos is discussed. A recent increase in the popularity of S. hippos as a catch-and-release sportfish has led to concerns by some anglers about post release survival of this species, particularly due to the depth of capture. Short term mortality of S. hippos capture at the sportfishing sites was assessed by monitoring fish held within an enclosure near the site of capture for up to 31 hours post release. The total hooking mortality of S. hippos subjected to catch-and-release angling within the Rottnest Island sportfishery is approximately 8%. Most of this observed mortality is delayed and occurs sometime after release. Although best handling practises require ongoing development, the current level of mortality associated with this catch-and-release fishery is considered acceptable. Furthermore, this mortality is likely to have little effect on the S. hippos population due to the high abundance of this species and the fact that even the highest fishing effort yields a relatively low catch. Seriola hippos exhibits a typical teleost neuroendocrine stress response associated with catch-and-release. The physiological dysfunction associated with the stress of capture in this species does not appear to cause any post release mortality. Instead, most mortality was attributable to barotrauma, however, although mortality in S. hippos increases with capture depth, this species is much less susceptible to depth induced mortality than other commonly targeted species in which barotrauma has been observed. This study developed key handling protocols for fishers who catch-and-release S. hippos at the Rottnest Island aggregation sites. These protocols cover aspects of catch-and-release fishing such as hook type, water depth, time at surface, release method and shark predation. Almost all S. hippos observed during capture from deep water released large quantities of gas from the opercular region, particularly during the last 10 to 20 m before reaching the surface. This phenomenon has also been witnessed by divers and fishers to occur under natural conditions. Investigations into this release of gas revealed this physoclistous species to exhibit unique swim bladder characteristics. Seriola hippos possess a membranous tube that connects the posterior-dorsal surface of the swim bladder internally to a region under each operculum externally. This connection, termed the swim bladder vent, allows the escape of expanding swim bladder gases on rapid ascent. The presence of the swim bladder vent provides an explanation as to why the incidence of external barotrauma symptoms in S. hippos captured from the deepwater was low. The ability to expel excess swim bladder gases during rapid ascent whilst retaining full swim bladder function is likely to offer this semi-pelagic species considerable advantages when hunting prey, avoiding predators and engaging in spawning activities. Preliminary estimates of total mortality indicated that S. hippos is not currently subjected to a high level of fishing pressure. However, managers must remain mindful of the fact that the size at which females reach sexual maturity, i.e. 888 mm TL, is greater than the current minimum legal length, i.e. 600 mm, and thus fishers are currently allowed to harvest sexually immature fish. Furthermore, the effectiveness of future conservation measures must consider the large scale migration and spawning strategy undertaken by this species in order to ensure its protection. The collaborative research approach undertaken during this study demonstrated that a high level of community engagement produced a large amount of research interest, increased stakeholder satisfaction from project input, improved understanding of research outcomes, and increased research uptake, all of which has led to increased stewardship and conservation of the S. hippos fishery and fisheries resources in general. Indeed, projects of this nature would not be possible without this type of approach.

An investigation into the spatial ecology and effects of catch-and-release angling on the physiology and behavior of striped bass was conducted. Fine-scale behavior was assessed by tagging fish with acoustic transmitters equipped with pressure and tri-axial accelerometer sensors and tracking them within a fixed array (n=34 receivers) in a Massachusetts estuary. Activity space changed significantly over the course of the season and increased with water temperature. Striped bass most frequently exhibited low levels of locomotory activity representing 67% of total activity measurements, with occasional high activity and burst swimming, often within the upper 3 m of the water column. Depth distribution of striped bass remained shallower when temperatures peaked at over 21 oC. Diel vertical migration was present with shallowest depths observed during the day and greatest depths during high tide. To investigate catch-and-release consequences, 102 striped bass were angled and blood sampled between July and November 2011. A subsample of 35 striped bass (July n=11, August n=11, September n=13) were implanted with tri-axial acoustic accelerometers to assess relative behavior and survival post-release. Results from principle component analyses produced five factors describing 72.7% of the variance for blood physiology parameters, total length, and water temperature. Subsequently, only eigenvalues from PC1, with high loading for blood lactate, plasma sodium and chloride, and total length, were significantly correlated with fight time. Eight individual fish were detected within 12 hours of release and exhibited their greatest mean daily activity space estimate within that time (1.5 km2 ± 0.6, 50%; 5.6 km2 ± 2.2, 95%). Depth ranged from 0-6.15 m (1.89±1.3 m) and acceleration ranged from 0.095-3.51 ms-2 (0.95±0.33). In summary, no observed mortality suggests that fish were able to recover from the physical and physiological impacts of angling. This thesis has increased the understanding of striped bass ecology and will help promote future conservation and management initiatives for striped bass and facilitate additional research.

The objectives of this study were to measure injuries and impairments directly observed from gags Mycteroperca microlepis caught and released within a large-scale recreational fishery, develop methods that may be used to rapidly assess the condition of reef fish discards, and estimate the total portion of discards in the fishery that suffer latent mortality. Fishery observers were placed on for-hire charter and headboat vessels operating in the Gulf of Mexico from June 2009 through December 2012 to directly observe reef fishes as they were caught by recreational anglers fishing with hook-and-line gear. Fish that were not retained by anglers were inspected and marked with conventional tags prior to release. Fish were released in multiple regions over a large geographic area throughout the year and over multiple years. The majority of recaptured fish were reported by recreational and commercial fishers, and fishing effort fluctuated both spatially and temporally over the course of this study in response to changes in recreational harvest restrictions and the Deepwater Horizon oil spill. Therefore, it could not be assumed that encounter probabilities were equal for all individual tagged fish in the population. Fish size and capture depth when fish were initially caught-and-released also varied among individuals in the study and potentially influenced recapture reporting probabilities. The Cox proportional hazards regression model was used to control for potential covariates on both the occurrence and timing of recapture reporting events so that relative survival among fish released in various conditions could be compared. A total of 3,954 gags were observed in this study, and the majority (77.26%) were released in good condition (condition category 1), defined as fish that immediately submerged without assistance from venting and had not suffered internal injuries from embedded hooks or visible damage to the gills. However, compared to gags caught in shallower depths, a greater proportion of gags caught and released from depths deeper than 30 meters were in fair or poor condition. Relative survival was significantly reduced (alpha (underline)<(/underline)0.05) for gags released in fair and poor condition after controlling for variable mark-recapture reporting rates for different sized discards among regions and across months and years when individual fish were initially captured, tagged and released. Gags released within the recreational fishery in fair and poor condition were 66.4% (95% C.I. 46.9 to 94.0%) and 50.6% (26.2 to 97.8%) as likely to be recaptured, respectively, as gags released in good condition. Overall discard mortality was calculated for gags released in all condition categories at ten meter depth intervals. There was a significant linear increase in estimated mortality from less than 15% (range of uncertainty, 0.1-25.2%) in shallow depths up to 30 meters, to 35.6% (5.6-55.7%) at depths greater than 70 meters (p < 0.001, R2 = 0.917). This analysis demonstrated the utility of the proportional hazards regression model for controlling for potential covariates on both the occurrence and timing of recapture events in a large-scale mark-recapture study and for detecting significant differences in the relative survival of fish released in various conditions measured under highly variable conditions within a large-scale fishery.

Abstract: Recreational fishing is one of popular outdoor activities and a growing business in Sweden. However, preceding researches had shown that recreational fisheries may contribute to overfishing as much as commercial fisheries. One of the ways to reduce anglers’ impact on fish populations is the practice of releasing caught fish (catch and release; C&amp;R). C&amp;R is often seen as an ethical and sustainable way of fishing that supports fish conservation. Anglers may obtain C&amp;R information and guidelines from different sources, such as fishing club, fishing magazines, state agencies. As the internet is increasingly becoming an important source for anglers to obtain updated fishing information, fishing tourism operators could be a principal actor to provide C&amp;R information and guidelines through their websites. At the same time there is lack of information on the presence and quality of C&amp;R information at Swedish websites. As international tourists are important group of anglers that use tourism operators’ services, and due to the language limitation of the author, this study focused on websites in English language. Therefore, this study aimed at investigating the presence and quality of C&amp;R information and guidelines in English language provided by fishing tourism operators’ websites in Sweden. The study followed the quantitative content analysis approach by assigning categories and counting the frequencies in the text found on the fishing tourism operators’ websites. First, the websites were scanned to check if C&amp;R information was present. Then, the number of clicks needed to retrieve this information was counted to measure its accessibility. Finally, a C&amp;R information quality score was calculated by adding up scores based on different type and quality of the information found on the websites, including 12 criteria of the C&amp;R best practice guidelines developed by Sims and Danylchuk (2017). The study found that 66 out of 151 analyzed websites provided C&amp;R information and guidelines which generally easily  accessed (two clicks on average). However, in general the websites had a low average quality score of the C&amp;R information and guidelines. Moreover, there was a high variability in how the information was presented on the websites, suggesting lack of standardized guidelines that fishing tourism operators could refer to. Consequently, there is a need to encourage and support more fishing tourism operators to provide a high quality C&amp;R information and guidelines on their websites.

Made available in DSpace on 2015-04-11T13:56:28Z (GMT). No. of bitstreams: 1 Lorenzo Barroco.pdf: 722257 bytes, checksum: 356df29a6c95a7e03f6ab0ca96899495 (MD5) Previous issue date: 2013-05-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The expansion of recreational fishing in Brazil started in the 1990 s, when more and more people came to the Amazon in search of peacock bass (Cichla spp.). The behavior of this cichlid, which attacks lures, is especially exciting for anglers. The middle Negro River has become one of the most popular areas of sport fishing of the world, where the largest peacock bass can be found. The importance of catch-and-release fishing as an sustainable fishing strategy has been shown to directly help conserve peacock bass fish stocks in the region. In this study, peacock bass mortality was evaluated in relation to catch-and-release fishing, comparing two types of artificial lures: the jig and a traditional middle-water type. Fish, samples were collected in January/February and October/November of 2012 in the Unini River, a right margin tributary of the Negro River, in the municipal region of Barcelos in Amazonas State. A total of 191 peacock bass were caught, 90 by jig lure and the rest by the middle-water lure. Both fish groups were submitted to experimental confinement during a period of three days. In both groups, 30 fish were confined individually and 60 confined collectively. Additionally, 11 fish from the second group had radio transmitters attached to be used in telemetry. The mortality rate was calculated for each type of lure and type of confinement. No mortality was encountered for the group caught with a jig beat lure. In comparison, the middle-water lure showed a mortality rate of 1.66% for the collective confinement and 18.18% for the monitoring involving telemetry. For both types of lures, no mortality was observed for fish confined individually. The data was plotted using a Kruskal-Wallis variance analysis that showed values of X2 (1.179) = 0,502 and p= 0,478 for confined environments. The same test show values of X2 (1.179) = 1,005 e p= 0,316 for the different lures. The results indicated that neither confinement type or lure type had a significantly negative impact on the peacock bass mortality rate from the catch-and-release fishery, demonstrating that catchand- release fishing has a very small impact on peacock bass mortality. Therefore, this type of recreational fishing is beneficial as a strategy to help conserve peacock bass fish stocksfishery / A expansão da pesca amadora no Brasil teve inicio na década de 90 e tem alcançado os rios de água preta na região Amazônica, principalmente no médio Rio Negro onde são encontrados os grandes tucunarés (Cichla spp.). Com o acentuado crescimento desta atividade na região, a prática do pesque-solte vem sendo proposta como um procedimento sustentável na pesca esportiva dos tucunarés da região. Contudo, em face das dúvidas acerca da eficácia desta modalidade de pesca, avaliamos o efeito do pesque-solte sobre a sobrevivência do tucunaré, comparando dois tipos de iscas artificiais o jig e a meia-água. Foram realizados dois ensaios nos períodos de janeiro/fevereiro e outubro/novembro de 2012 no rio Unini, afluente da margem direita do rio Negro (Barcelos-AM). Em total foram capturados 191 tucunarés: 90 por iscas jig e os demais por iscas de meiaágua. Ambos os grupos de peixes foram submetidos a experimentos de confinamento por um período de 3 dias. Do primeiro grupo, 30 peixes foram confinados individualmente e 60 coletivamente. No segundo grupo, 30 foram confinados individualmente e 60 coletivamente. Adicionalmente, 11 peixes deste grupo foram marcados com transmissores de rádio para monitoramento por telemetria. A taxa de mortalidade foi calculada através do percentual dos indivíduos mortos para cada tipo de isca e ambiente de confinamento. Não houve mortalidade para o grupo de tucunaré capturado com jig. Por outro lado, a isca de meia-água apresentou taxa de mortalidade de 1,66% para o confinamento coletivo e de 18,18% para os monitorados por telemetria, não havendo, portanto mortes de indivíduos confinados individualmente. Estes dados foram analisados por meio de uma análise de variância Kruskal-Wallis, onde apresentaram valores de X2 (1.179) = 0,502 e p= 0,478 para os ambientes de confinamentos. O mesmo teste apresentou valores de X2 (1.179) = 1,005 e p= 0,316 para as iscas utilizadas. Dessa forma, os resultados indicam que ambos, o tipo de ambiente e o tipo de isca, não apresentaram influencia significativa sobre a taxa de mortalidade dos tucunarés na prática do pesque-solte. Estes resultados mostram que a prática desta modalidade de pesca amadora, resulta em baixa taxa de mortalidade para os tucunarés. Sendo assim o pesque-solte se mostra uma atividade que não prejudica a sustentabilidade dos estoques pesqueiros de tucunaré. Palavras-chave: Pesque-solte; tucunaré; pesca amadora; mortalidade de peixes

Heteropolymeric O antigen (O-Ag)-capped lipopolysaccharide is the principal constituent of the Gram-negative bacterial cell surface. It is assembled via the integral inner membrane (IM) Wzx/Wzy-dependent pathway. In Pseudomonas aeruginosa, Wzx translocates lipid-linked anionic O-Ag subunits from the cytoplasmic to the periplasmic leaflets of the IM, where Wzy polymerizes the subunits to lengths regulated by Wzz1/2. The Wzx and Wzy IM topologies were mapped using random C-terminal-truncation fusions to PhoALacZα, which displays PhoA/LacZ activity dependent upon its subcellular localization. Twelve transmembrane segments (TMS) containing charged residues were identified for Wzx. Fourteen TMS, two sizeable cytoplasmic loops (CL), and two large periplasmic loops (PL3 and PL5 of comparable size) were characterized for Wzy. Despite Wzy PL3–PL5 sequence homology, these loops were distinguished by respective cationic and anionic charge properties. Site-directed mutagenesis identified functionally-essential Arg residues in both loops. These results led to the proposition of a “catch-and-release” mechanism for Wzy function. The abovementioned Arg residues and intra-Wzy PL3–PL5 sequence homology were conserved among phylogenetically diverse Wzy homologues, indicating widespread potential for the proposed mechanism. Unexpectedly, Wzy CL6 mutations disrupted Wzz1-mediated regulation of shorter O-Ag chains, providing the first evidence for direct Wzy–Wzz interaction. Mutagenesis studies identified functionally-important charged and aromatic TMS residues localized to either the interior vestibule or TMS bundles in a 3D homology model constructed for Wzx. Substrate-binding or energy-coupling roles were proposed for these residues, respectively. The Wzx interior was found to be cationic, consistent with translocation of anionic O-Ag subunits. To test these hypotheses, Wzx was overexpressed, purified, and reconstituted in proteoliposomes loaded with I−. Common transport coupling ions were introduced to “open” the protein and allow detection of I− flux via reconstituted Wzx. Extraliposomal changes in H+ induced I− flux, while Na+ addition had no effect, suggesting H+-dependent Wzx gating. Putative energy-coupling residue mutants demonstrated defective H+-dependent halide flux. Wzx also mediated H+ uptake as detected through fluorescence shifts from proteoliposomes loaded with pH-sensitive dye. Consequently, Wzx was proposed to function via H+-coupled antiport. In summary, this research has contributed structural and functional knowledge leading to novel mechanistic understandings for O-Ag biosynthesis in bacteria. / Bookmarks within the document have been provided for ease of access to a particular section in the body of the thesis. Each entry in the Table of Contents, List of Tables, and List of Figures has been "linked" to its respective position and as such can be clicked for direct access to the entry. Similarly, each in-text Figure or Table reference has been "linked" to its respective figure/table for direct access to the entry. / 1.) Canadian Institutes of Health Research (CIHR) Frederick Banting and Charles Best Canada Graduate Scholarship doctoral award, 2.) CIHR Michael Smith Foreign Study Award, 3.) Cystic Fibrosis Canada (CFC) doctoral studentship, 4.) University of Guelph Dean's Tri-Council Scholarship, 5.) Ontario Graduate Scholarship in Science and Technology, 6.) Operating grants to Dr. Joseph S. Lam from CIHR (MOP-14687) and CFC