<p>The intent of the work discussed in this dissertation is to apply the engineering methods of theory/modeling, numerics/computation, and experimentation to a diverse assemblage of projects. Several projects are discussed: probabilistic modeling of decompression sickness, comparative hydrodynamics of cetacean flippers, optimization of CT/MRI protocols, evaluation of modified catheters, rudder cavitation, and modeling of mass transfer in amphibian cone outer segments. </p><p>The first project discussed is the probabilistic modeling of decompression sickness (DCS). This project involved developing a system for evaluating the success of decompression models in predicting DCS probability from empirical data. Model parameters were estimated using maximum likelihood techniques, and exact integrals of risk functions and tissue kinetics transition times were derived. Agreement with previously published results was excellent including maximum likelihood values within one log-likelihood unit of previous results and improvements by re-optimization, mean predicted DCS incidents within 1.4% of observed DCS, and time of DCS occurrence prediction. Alternative optimization and homogeneous parallel processing techniques yielded faster model optimization times. The next portion of this project involved investigating the nature and utility of marginal decompression sickness (DCS) events in fitting probabilistic decompression models to experimental dive trial data. Three null models were developed and compared to a known decompression model that was optimized on dive trial data containing only marginal DCS and no-DCS events. It was found that although marginal DCS events are related to exposure to decompression, empirical dive data containing marginal and full DCS outcomes are not combinable under a single DCS model; therefore, marginal DCS should be counted as no-DCS events when optimizing probabilistic DCS models with binomial likelihood functions. The final portion of this project involved the exploration of a multinomial DCS model. Two separate models based on the exponential-exponential/linear-exponential framework were developed: a trinomial model, which is able to predict the probabilities of mild, serious and no-DCS simultaneously, and a tetranomial model, which is able to predict the probabilities of mild, serious, marginal and no-DCS simultaneously. The trinomial DCS model was found to be qualitatively better than the tetranomial model, for reasons found earlier concerning the utility of marginal DCS events in DCS modeling. </p><p>The next project discussed is comparative hydrodynamics of cetacean flippers. Cetacean flippers may be viewed as being analogous to modern engineered hydrofoils, which have hydrodynamic properties such as lift coefficient, drag coefficient and associated efficiency. The hydrodynamics of cetacean flippers have not previously been rigorously examined and thus their performance properties are unknown. By conducting water tunnel testing using scale models of cetacean flippers derived via computed tomography (CT) scans, as well as computational fluid dynamic (CFD) simulations, a baseline work is presented to describe the hydrodynamic properties of several cetacean flippers. It was found that flippers of similar planform shape had similar hydrodynamic performance properties. Furthermore, one group of flippers of planform shape similar to modern swept wings was found to have lift coefficients that increased with angle of attack nonlinearly, which was caused by the onset of vortex-dominated lift. Drag coefficient versus angle of attack curves were found to be less dependent on planform shape. Larger cetacean flippers were found to have degraded performance at a Re of 250,000 compared to flippers of smaller odontocetes, while performance of larger and smaller cetacean flippers was similar at a swim speed of 2 m/s. Idealization of the planforms of cetacean flippers was found to capture the relevant hydrodynamic effects of the real flippers, although unintended consequences such as the lift curve slope changing from linear to nonlinear were sometimes observed. A numerical study of an idealized model of the humpback whale flipper showed that the leading-edge tubercles delay stall compared to a baseline (no tubercle) flipper because larger portions of the flow remaining attached at higher angles of attack. </p><p>The third project discussed is optimization of CT/MRI protocols. In order to optimize contrast material administration protocols for Computed Tomography (CT) and Magnetic Resonance Imaging (MRI), a custom-built physiologic flow phantom was constructed to model flow in the human body. This flow phantom was used to evaluate the effect of varying volumes, rates, and types of contrast material, use of a saline chase, and cardiac output on aortic enhancement characteristics. For CT, reducing the volume of contrast material decreased duration peak enhancement and reduced the maximum value of peak enhancement. Increasing the rate of contrast media administration increased peak enhancement and decreased duration of peak enhancement. Use of a saline chase resulted in an increase in peak enhancement. Peak aortic enhancement increased when reduced cardiac output was simulated. For MRI, when the same volume of contrast material was injected at the same rate, the type of contrast material used has a significant effect on the greatest peak signal intensity and duration peak signal intensity. A higher injection rate of saline chaser is more advantageous than a larger volume of saline chaser to increase the peak aortic signal intensity using low contrast material doses. Furthermore, for higher volumes of contrast material, the effect of increasing the volume of saline chaser makes almost no difference while increasing the rate of injection makes a significant difference. When a saline chaser with a high injection rate is used, the dose of the contrast material may be reduced by 25-50% and more than 86% of the non-reduced dose peak aortic enhancement will be attained.</p><p>The next project discussed is evaluation of modified angiocatheters. In this study, a standard peripheral end hole angiocatheter was compared to those modified with side holes or side slits by using experimental techniques to qualitatively compare the contrast material exit jets, and by using numeric techniques to provide flow visualization and quantitative comparisons. A Schlieren imaging system was used to visualize the angiocatheter exit jet fluid dynamics at two different flow rates, and a commercial computational fluid dynamics (CFD) package was used to calculate numeric results for various catheter orientations and vessel diameters. Experimental images showed that modifying standard peripheral intravenous angiocatheters with side holes or side slits qualitatively changed the overall flow field and caused the exiting jet to become less well-defined. Numeric calculations showed that the addition of side holes or slits resulted in a 9-30% reduction of the velocity of contrast material exiting the end hole of the angiocatheter. With the catheter tip directed obliquely to the wall, the maximum wall shear stress was always highest for the unmodified catheter and always lowest for the 4 side slit catheter. Modified angiocatheters may have the potential to reduce extravasation events in patients by reducing vessel wall shear stress. </p><p>The next project discussed involves studying the effect of leading-edge tubercles on cavitation characteristics for marine rudders. Three different rudders were constructed and tested in a water tunnel: baseline, 3-tubercle leading edge, and 5-tubercle leading edge. In the linear (non-stall) regime, tubercled rudders performed equally to the smooth rudder. Hydrodynamic stall occurred at smaller angles of attack for the tubercled rudders than for the smooth rudder. When stall did occur, it was more gradual for the tubercled rudders, whereas the smooth rudder demonstrated a more dramatic loss of lift. At lower Re, the tubercled rudders also maintained a higher value of lift post-stall than the smooth rudder. Cavitation onset for the tubercled rudders occurred at lower angles of attack and higher values of cavitation number than for the smooth rudder, but cavities on the tubercled rudders were localized in the slots as opposed to the smooth rudder where the cavity spread across the entire leading edge. </p><p>In the final project discussed, modeling of mass transfer in amphibian cone outer segments, a detailed derivation of a simplified (continuum, one-dimensional) mathematical model for the radio-labeled opsin density profile in the amphibian cone outer segment is presented. This model relies on only one free parameter, which was the mass transfer coefficient between the plasmalemma and disc region. The descriptive equations were nondimensionalized, and scale analysis showed that advective effects could be neglected as a first approximation for early times so that a simplified system could be obtained. Through numeric computation the solution behavior was found to have three distinct stages. The first stage was marked by diffusion in the plasmalemma and no mass transfer in the disc region. The second stage first involved the plasmalemma reaching a metastable state whereas the disc region density increased, then involved both the plasmalemma and disc regions increasing in density with their distributions being qualitatively the same. The final stage involved a slow relaxation to the steady-state solution.</p> / Dissertation

Common bottlenose dolphins (Tursiops truncatus) are apex predators and indicators of localized ecosystem health. Accurate characterization of population demography is crucial to parameter predictions. However, descriptions of age growth investigations of odontocetes are limited to the postnatal life. In contrast, the modeled scenario for terrestrial mammalian growth has been described along a continuum of pre- and postnatal data. Few age distribution data exist for the western Gulf of Mexico despite the fact that life tables enable demographic comparisons among populations. The objective of this study was to characterize age, growth, and population-level behavior of bottlenose dolphins along Texas. This objective was accomplished by two discrete studies: age analysis, and population-level behavior. Teeth from 290 stranded individuals were extracted for the purposes of age determination. Curvilinear models (the Gompertz and the von Bertalanffy) were fit to postnatal length-at-age data. Fetal age was determined for 408 suspected fetal length records using validated fetal growth trends and empirical measurements from late-term fetuses. Growth analysis indicated that a Gompertz model fit length-at-age data better than a von Bertalanffy model. A postnatal Gompertz model explained less variation than a combined pre- and postnatal model (R2 = 0.9 and 0.94 respectively). The absolute growth rate and rate of growth decay tripled with the inclusion of fetal length and age data. In the second study, life tables were constructed for 280 individuals. Survivorship curves, mortality rates, intrinsic capacity for increase, and the population growth rate were calculated. Bottlenose dolphin mortality did not differ significantly by sex or age class. Survivorship was best characterized by a type III curve. Analyses indicated no substantial increase (r = -0.07), and that the population is not replacing itself in the next time-step (y = 0.93). Bottlenose dolphins conform to a number of eutherian mammalian trends: the production of precocial young, calving seasonality, and rapid fetal growth rate. Population level behavior suggests a population retraction possibly as a compensatory response to ecosystem perturbation rather than a population decline. Reproductive information will confirm population status and stability in the future. This study is the first to demonstrate a significant impact of cetacean fetal growth parameters on postnatal growth trajectory.

An important step for protecting Endangered species is the identification of critical habitat. This can be especially challenging for deep ocean species. Northern bottlenose whales (Hyperoodon ampullatus) are deep-diving beaked whales of the North Atlantic. A population of this species occurs along the edge of the Scotian Shelf primarily in three submarine canyons that have been identified as critical habitat for the population: the Gully (the largest submarine canyon off eastern North America), Shortland Canyon and Haldimand Canyon. The Scotian Shelf population is considered Endangered mainly due to its small numbers and the anthropogenic threats it faces. The primary objective of my research was to further identify critical habitat of the population using passive acoustic monitoring, increasing knowledge of how the whales use the canyons and adjacent areas throughout the year. A review of the literature on cetacean associations with submarine canyons indicates that various mechanisms may act to attract cetaceans to these features. While many different species occur in canyons globally, they appear to be particularly important habitat for beaked whales. I developed an automated click detection algorithm customized for detecting northern bottlenose whale echolocation clicks, and long-term acoustic recordings were analyzed to examine the presence and relative abundance of northern bottlenose whales on the Scotian Slope over various spatial and temporal scales. The whales occurred in the area consistently throughout the year and all three canyons, as well as the area between canyons, appeared to be important foraging grounds for the population. The whales displayed diurnal foraging patterns. I also investigated niche separation between northern bottlenose whales and sperm whales (Physeter macrocephalus), another deep diving species. The presence of the two species was positively correlated over all spatial and temporal scales examined. These results indicate that areas within and adjacent to the Gully are important foraging grounds for northern bottlenose whales throughout the year. Furthermore, in addition to the canyons themselves, the shelf-edge areas between the Gully, Shortland and Haldimand canyons may constitute critical habitat for the whales. This research will be used to inform management measures relevant to the protection and recovery of this Endangered population.

abstract: Whale watching has been hailed by environmental non-governmental organizations like Greenpeace and the International Fund for Animal Welfare as a responsible form of tourism that has the potential to enhance conservation outcomes for cetaceans, while also supporting the economic development of coastal communities. Tourism research suggests that while it is possible for whale watching to provide these benefits, it may also have considerable costs to members of host communities and cetaceans. My dissertation sought to gather data on the economic, ecological, and social impacts of whale watching in the Caribbean in order to evaluate the industry's performance in the region. My project thus took the form of three sub-projects. The first used an ordinary least squares analysis to examine the relationship between Caribbean country characteristics and whale watching expenditures. This analysis showed that a country's level of development changes the strength of correlations, that mass tourism development is negatively associated with whale watching profits, and that cetacean biodiversity and whale watching regulations designed to protect cetaceans both had positive relationships with the whale watching industry. In the second sub-project, I developed an index of Caribbean cetacean vulnerability to the negative impacts of whale watching with a traditional literature review informed by systematic methods. The index illustrated that both target and non-target species had vulnerabilities, and that regulations addressing these issues in the Caribbean were lacking overall. Considerable gaps in data were also identified. Finally, I used qualitative interviews in Dominica and the Dominican Republic to gather information on resident perceptions of whale watching. This analysis revealed overall positive perceptions of the industry in both countries, but also uncovered considerable levels of social conflict surrounding whale watching. Taken together, the results of my study suggest that better regulatory structures, investment in the local community, and efforts to maximize cooperation are needed in order for the Caribbean whale watch industry to better serve local communities, while mitigating its impacts on cetaceans. / Dissertation/Thesis / Doctoral Dissertation Environmental Social Science 2017

Marine mammal mass strandings have been documented for centuries, even going as far back as Aristotle. For just as long, the causes of these mass strandings have been questioned. With every species of cetacean known to have stranded, it is important to find trends to understand and prevent these strandings from occurring. With a heightened awareness of this issue, leading to the creation of marine mammal stranding networks throughout the United States in the 1990s, a more comprehensive approach to data collection has helped with the study. Issues such as seasonality, weather, topography, and disease have all been observed as a potential cause of these events. This study attempted to look at the Atlantic Coast of the United States, and its documented mass strandings from 1997-2011. Stranding data taken from the Northeast and Southeast US Marine Mammal stranding network database provided a basis for the study of these mass strandings. Many of the possible causes of these strandings, including seasonality, location, and species were studied. There was some correlation found between seasons and stranding, meaning there are certain times of the year when a cetacean pod may be more likely to strand.

The bycatch of cetaceans in fishing gear is considered to be one of the biggest conservation threats to these species. Gear modifications have the potential to reduce these bycatches in global fisheries but there is little available information on how such modifications may change the fishing performance of gear, or indeed the behavior of cetaceans interacting with fishing gear. Generalized linear models (GLMs) were used to identify factors related to cetacean bycatches in UK bottom set gillnets. Rigged net height had a significant positive relationship with harbour porpoise (Phocoena phocoena) bycatch in ICES Area VII suggesting that lowering the profile of gillnets may have the potential to reduce bycatch rates. Modifications to gillnets, such as changing the amount of floatation or increasing the density of the meshes, were found to have significant effects on the active fishing heights of these nets. However, results from a bycatch mitigation trial in Argentina showed that the reduced fishing profile of one experimental net did not result in a concurrent reduction in the bycatch rate of Franciscana dolphins (Pontoporia blainvillei). While there was no significant difference in the rate, length or intensity of harbour porpoise encounters in the presence or absence of gillnets, the proportion of fast echolocation click trains were significantly higher when a net was present, indicating that porpoises either increased acoustic inspection of the net or foraging in the vicinity of the net. An analysis of underwater video footage collected inside trawl nets in an Australia fishery showed that bottlenose dolphins (Tursiops sp.) were present inside nets more frequently than they were caught and were actively foraging inside these nets. The orientation of dolphins inside these nets indicates that the current design of excluder devices used in this fishery could be improved to further reduce bycatch rates.

The main purpose of this study was to produce and test the reliability of predictive models of cetacean distributions off the west coast of Scotland. Passive acoustic and visual surveys were carried out from platforms of opportunity between 2003 and 2005. Acoustic identifications were made primarily of harbour porpoises (Phocoena phocoena), delphinids, and sperm whales (Physeter macrocephalus). Generalised Additive Models (GAMs) were used to relate species’ distributions to a range of environmental variables over a range of temporal and spatial scales. Predictive models of delphinid distributions showed both inter-annual and inter-month variations. Combining all data for all months and years resulted in a model that combined the environmental influences from each monthly and yearly model. Overall, delphinids were found to associate with the deep (> 400m) warm water (10.5°C-12.5°C), and in areas of deep thermocline. Relationships between sperm whales and environmental variables were consistent over changes in grain size (9 km or 18 km), but not between areas. Although sperm whales were distributed in deep water characterised by weak thermoclines and strong haloclines in the most northerly area (Faroe-Shetland Channel), they were found in deep productive areas with cold surface temperature in the more southerly waters (Rockall Trough). Within the southern Inner Hebrides, high use areas for harbour porpoises were consistently predicted over time (in years) and with differing survey techniques (acoustic versus visual), but not over space (southern Inner Hebrides versus whole of the Inner Hebrides). Harbour porpoises were mainly distributed in areas with low tidal currents and with higher detection rates during spring tides. The use of prey as a predictor variable within models of delphinid distribution shows some promise: there were correlations between delphinid and herring (Clupea harengus) in shelf-waters in 2005 but not in 2004. These models can be used in mitigating acoustic threats to cetaceans in predicted high use areas off the west coast of Scotland.

Submitted by Verena Bastos (verena@uefs.br) on 2015-09-21T14:21:13Z No. of bitstreams: 1 DISSERTA??O_Mariana Santos de Jesus_2013_v.FINAL.pdf: 2182580 bytes, checksum: 54eae6f08c950fc41cd0623949c61663 (MD5) / Made available in DSpace on 2015-09-21T14:21:13Z (GMT). No. of bitstreams: 1 DISSERTA??O_Mariana Santos de Jesus_2013_v.FINAL.pdf: 2182580 bytes, checksum: 54eae6f08c950fc41cd0623949c61663 (MD5) Previous issue date: 2013-03-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The Brazilian semiarid region undergoes seasonal distribution of rainfall that is concentrated in short periods of the year, combined with shallow and stony soils with low organic matter content and ability to retain moisture. Given these limitations, has intensified in this region the use of cactus as a food source herd due to its high capacity to adapt to the climate of this region. This study evaluated for agronomic characteristics, chemical characteristics and chromosome 20 clones preselected by Oliveira 2010, forming part of the breeding program of cactus pear State University of Feira de Santana, in existence since December 2008. Two experiments were conducted. In the first containing palm girl (Nopalea cochenillifera & Salm Dyck) and the second with giant cactus (Opuntia ficus-indica Mill). The experimental design was randomized blocks with five replicates, the spacing was 0.5 x 1.0 m (x plant rows) and fertilization administered 30 t/ha-1 of manure. Data were submitted to ANOVA and Tukey test (p <0.01 and p <0.05). For agronomic characteristics, the tiny palm clones showed no significant differences between the observed means. For the giant cactus, clone 4:06 stood out compared to the other featuring the best averages for the number of cladodes per plant. In assessing chemical was observed on average 69.91% NDF, 13.09% ADF and 8.49% CP for Palm kid. For giant cactus values were 45.63% NDF, 18.20% ADF and 9.18% PB. Chromosome analysis revealed that the numbers ranged from 2n = 22 in the palm girl to 2n = 88 in the giant cactus, without occurrence of disploidias or aneupoidias plants analyzed. It was found that clones are very promising for breeding programs, and are recommended for cultivation in the region of Feira de Santana-BA. / O semi?rido brasileiro apresenta sazonalidade na distribui??o de chuvas que s?o concentradas em per?odos curtos do ano, aliados a solos pouco profundos e pedregosos com baixo teor de mat?ria org?nica e capacidade de reter umidade. Diante destas limita??es, tem-se intensificado nessa regi?o o uso da palma forrageira como fonte de alimento do rebanho devido a sua alta capacidade de adapta??o ao clima dessa regi?o. Este trabalho objetivou avaliar quanto ?s caracter?sticas agron?micas, bromatol?gicas e cromoss?micas 20 clones pr? selecionados por Oliveira (2010), que fazem parte do programa de melhoramento gen?tico da palma forrageira da universidade Estadual de Feira de Santana, existente desde Dezembro de 2008. Foram estabelecidos dois experimentos. No primeiro contendo palma mi?da (Nopalea cochenillifera Salm & Dyck) e o segundo com palma gigante (Opuntia f?cus-indica Mill). O delineamento experimental utilizado foi de blocos ao acaso com cinco parcelas, o espa?amento foi 0,5 x 1,0 m (plantas x fileiras) e a aduba??o administrada de 30 t/ha-1 de esterco bovino. Os dados foram submetidos ? an?lise de vari?ncia e teste de Scott-Knott (p<0,05). Para as caracter?sticas agron?micas, os clones de palma mi?da foram inferiores em rela??o ?s testemunhas IPA-sert?nia e IPA-mi?da para os caracteres CC, DC e AC. Para a palma gigante, o clone 04 destacou-se em rela??o aos demais diferindo estatisticamente quanto ao n?mero de clad?dios por planta. Na avalia??o bromatol?gica observou-se em m?dia 69,91% de FDN, 13,09% de FDA e 8,49% de PB para a palma mi?da. Para palma gigante os valores m?dios foram 45,63% FDN, 18,20% FDA e 9,18% PB. As an?lises cromoss?micas revelaram que os n?meros variaram de 2n=22 na palma mi?da a 2n=88 na palma gigante, sem ocorr?ncia de disploidias ou aneupoidias nas plantas analisadas. Verificou-se que os clones s?o bastante promissores para programas de melhoramento, e s?o recomend?veis para cultivo na regi?o de Feira de Santana-BA.

Made available in DSpace on 2016-12-23T13:28:51Z (GMT). No. of bitstreams: 1 Thais de Assis Volpi.pdf: 2306298 bytes, checksum: 2140568058b31aa143951295f1f9bea4 (MD5) Previous issue date: 2012-02-28 / O golfinho-rotador-pantropical (Stenella longirostris longirostris) ocorre em águas tropicais e subtropicais de todos os oceanos. No litoral brasileiro, ocorre principalmente em águas tropicais entre 170 e 2700m de profundidade, sendo muito comum em Fernando de Noronha. Pouco se sabe sobre o seu fluxo gênico e diversidade genética no oceano Atlântico Sul. O presente estudo teve como objetivo avaliar a variabilidade genética de golfinhos-rotadores em diferentes localidades do litoral brasileiro. Duas regiões do DNA mitocondrial foram analisadas: região controle (D-loop) e citocromo oxidase subunidade I (COI). 82 indivíduos foram amostrados, correspondentes a quatro grupos de golfinhos amostrados no Nordeste do Brasil (G1), em Fernando de Noronha (G2 e G3) e no Sudeste e Sul do Brasil (G4). As amostras foram obtidas por raspagem de pele, biópsia com balestra e de animais mortos encalhados. 79 sequências com 414bp de D-loop e 48 com 714bp da região COI foram analisadas. Além destas, 45 sequências foram geradas a partir de fragmentos concatenados entre D-loop e COI. 115 sequências do GenBank (109 de D-loop e seis COI) foram incluídas para compreender a relação dos haplótipos brasileiros com outras populações mundiais. Os quatro grupos brasileiros avaliados apresentaram diferenciação genética significativa entre eles (Fst>0,05 com P<0,05) e, portanto, cada um deles foi considerado como sendo uma população diferente. G4 apresentou os maiores índices de diversidade nucleotídica e haplotípica, enquanto G2 e G3 apresentaram os menores. O baixo fluxo gênico entre as populações de golfinhos-rotadores de Fernando de Noronha em relação às populações não insulares pode indicar a fidelidade de sítio desses animais em águas insulares. As populações do litoral brasileiro são geneticamente diferentes; no entanto, todos compartilharam haplótipos com golfinhos dos oceanos Índico e Pacífico, além de animais da porção norte do Atlântico. G4 mostrou maior similaridade genética com golfinhos de outros oceanos do que com as populações de outros golfinhos-rotadores brasileiros. A população G2 (com maior número de amostras) apresentou maior similaridade genética com a população do Pacífico, mesmo quando comparado com a outra população de Fernando de Noronha (G3). Assim, é possível que o fluxo gênico de golfinhos no Brasil não é atribuído a distância geográfica entre eles, mas por outros fatores históricos, ecológicos e comportamentais / The pantropical spinner dolphin (Stenella longirostris longirostris) occurs in tropical and subtropical waters of all oceans. In the Brazilian coast, it occurs mainly in tropical waters between 170 and 2700m depth, being very common in Fernando de Noronha Archipelago. Little is known about its gene flow and genetic diversity in South Atlantic Ocean. The present study aimed to evaluate the genetic variability of spinner dolphin in different localities of the Brazilian coast. Two regions of the mitochondrial DNA were analyzed, control region (D-loop) and cytochrome Oxidase subunit I (COI). 82 individuals were sampled, corresponding to four putative groups of dolphins sampled in Northeast Brazil (G1), in Fernando de Noronha (G2 and G3) and in the Southeast and South of Brazil (G4). The samples were obtained by skin swabbing, skin biopsy, and dead animals found stranded. 79 sequences with 414bp for D-loop and 48 with 714bp for COI region were analyzed. In addition to these, 45 sequences were generated from the link between fragments of D-loop and COI. 115 GenBank sequences (109 of D-loop and six of COI) were included to understand the relationship of Brazilian haplotypes with other world populations. The four Brazilian groups evaluated showed significant intergroup genetic differentiation (Fst>0.05 with P<0.05), therefore, each one of them was considered to be a different population. G4 presented the highest nucleotide and haplotypic diversity indices, while G2 and G3 showed the lowest. The low gene flow between the spinner dolphin populations from Fernando de Noronha in relation to the non insular populations may indicate site fidelity of these animals to insular waters. The populations in the Brazilian coast are genetically distinct; however all share haplotypes with dolphins from Indian and Pacific oceans, in addition to animals of the northern portion of the Atlantic. G4 showed more genetic similarity with dolphins from other oceans than with other spinner dolphin Brazilian populations. The population G2 (with the highest number of samples) showed greater genetic similarity with the Pacific population, even when compared with another population of Fernando de Noronha (G3). Thus, it is possible that the gene flow of spinner dolphins in Brazil is not given by the geographical distance among them, but by other historical, ecological and behavioral factors

Since the 1950s, more than 6 million dolphins have died as by-catch in the American yellowfin tuna fishery. These deaths were not caused by accidental incidents between fishermen and dolphins but resulted from a method of fishing that purposefully targeted these animals in order to catch yellowfin tuna. Referred to as “fishing on porpoise,” this technique remained an industry secret for decades. By the early 1970s, however, dolphin by-catch had become a major environmental issue in the United States, thanks to the work of William F. Perrin. In the following years, politicians, scientists, environmentalists, and members of the tuna industry struggled with how best to resolve the problem. While the debates that arose from the “tuna-porpoise controversy” helped to dramatically reduce dolphin by-catch, these solutions did not come easily. This thesis looks to bring this forgotten moment in American environmental history to the historical forefront by exploring the origins and early years of the tuna-porpoise controversy. By examining this period, this thesis will show why fishermen first used dolphins to catch tuna in the 1950s, how and why dolphin by-catch became such a major environmental issue in the 1970s, and what various groups and individuals did to ameliorate the problem during the period. / Graduate