Orientador: Miguel Petrere Júnior / Banca: Roberto Goitein / Banca: Paulo Emílio Vanzolini / Banca: Otto Bismarck Fazzano Gadig / Banca: Teodoro Vaske Junior / Doutor

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Mobile Bay is a dynamic estuary home to a diverse faunal assemblage, which includes several species of batoid fishes (Chondrichthyes: Batoidea). To better understand the dynamics of this batoid assemblage, batoids were opportunistically sampled from 440 trawls performed in and around Mobile Bay from 2016 to 2017. The species Hypanus sabinus and Gymnura lessae were the most common batoids collected (86% of catch). PERMANOVA analysis found the variables day length, location, year, and water temperature best described catch variability. Furthermore, stomach contents from Gymnura lessae were sampled to investigate its diet. Most prey were heavily degraded, thus DNA metabarcoding was used to enhance prey identification. Most prey (88.3%) were from the families Sciaenidae and Engraulidae, and the variables season and sex best explained the dietary variability. These data will be necessary for modeling potential habitat and dietary shifts of Mobile Bay’s batoids as climate change and anthropogenic disturbances alter estuaries.

Fishes are the most speciose group of living vertebrates, making up more than half of extant vertebrate diversity. They have evolved a wide array of swimming modes and body forms, including the batoid elasmobranchs, the dorsoventrally flattened skates and rays, which swim via oscillations or undulations of a broad pectoral fin disc. In this work I offer insights into locomotion by an undulatory batoid, freshwater stingray Potamotrygon orbignyi (Castelnau, 1855), combining studies of live animals, physical models, and preserved specimens. In Chapter 1, I quantify the three-dimensional kinematics of the P. orbignyi pectoral fin during undulatory locomotion, analyzing high-speed video to reconstruct three-dimensional pectoral fin motions. A relatively small portion (~25%) of the pectoral fin undulates with significant amplitude during swimming. To swim faster, stingrays increase the frequency, not the amplitude of propulsive motions, similar to the majority of studied fish species. Intermittently during swimming, a sharp, concave-down lateral curvature occurred at the fin margin; as the fin was cupped against the pressure of fluid flow this curvature is likely to be actively controlled. Chapter 2 employs a simple physical model of an undulating fin to examine the ground effects that stingrays may experience when swimming near a substrate. Previous research considering static air- and hydrofoils indicated that near-substrate locomotion offers a benefit to propulsion. Depending on small variations in swimming kinematics, undulating fins can swim faster near a solid boundary, but can also experience significant increases (~25%) in cost-of-transport. In Chapter 3, I determine how pectoral and pelvic fin locomotion are combined in P. orbignyi during augmented punting, a hybrid of pectoral and pelvic fin locomotion sometimes employed as stingrays move across a substrate. The timing of pectoral and pelvic fin motions is linked, indicating coordination of thrust production. Chapter 4 discusses pectoral fin structure and morphological variations within the fin, correlating morphology with the swimming kinematics observed in Chapter 1. Passive and active mechanisms may stiffen the anterior fin to create the stable leading edge seen during swimming; stingrays have converged on several structural features (fin ray segmentation and branching) shared by actinopterygian fishes.

Worldwide declines in populations of large elasmobranchs and the potential cascading effects on marine ecosystems have garnered considerable attention. Far less appreciated are the potential ecological impacts of changes in abundances of small to medium bodied elasmobranchs mesopredators. Crucial to elucidating the role of these elasmobranchs is an understanding of their habitat use and foraging ecology in pristine conditions. I investigated the trophic interactions and factors driving spatiotemporal variation in abundances of elasmobranch mesopredators in the relatively pristine ecosystem of Shark Bay, Australia. First, I describe the species composition and seasonal habitat use patterns of elasmobranch mesopredator on the sandflats of Shark Bay. Juvenile batoids dominated this diverse community and were extremely abundant in nearshore microhabitats during the warm season. Stomach content analysis and stable isotopic analysis revealed that there is a large degree of dietary overlap between common batoid species. Crustaceans, which tend to be found in seagrass habitats, dominated diets. Despite isotopic differences between many species, overlap in isotopic niche space was high and there was some degree of individual specialization. I then, investigated the importance of abiotic (temperature and water depth) and biotic (prey and predator abundance) factors in shaping batoid habitat use. Batoids were most abundant and tended to rest in shallow nearshore waters when temperatures were high. This pattern coincides with periods of large shark abundance suggesting batoids were seeking refuge from predators rather than selecting optimal temperatures. Finally, I used acoustic telemetry to examine batoid residency and diel use of the sandflats. Individual batoids were present on the sandflats during both the warm and cold seasons and throughout the diel cycle, suggesting lower sandflat densities during the cold season were a result of habitat shifts rather than migration out of Shark Bay. Combined, habitat use and dietary results suggest that batoids have the potential to seasonally impact sandflat dynamics through their presence, although foraging may be limited on the sandflats. Interestingly, my results suggest that elasmobranch mesopredators in pristine ecosystems probably are not regulated by food supply and their habitat use patterns and perhaps ecosystem impacts may be influenced by their predators.

This bachelor thesis explores the threat of Stingrays, fake cell towers, to the mobile network. The increasing availability of open-source technology and hardware has made it easier to build Stingrays. Stingrays can threaten the privacy and security of individuals and their devices, making it critical to understand the effectiveness and practicalities of the attack. This study evaluates the feasibility and the practical danger of Stingrays using open-source software and available hardware, filling a gap in research on the subject. First, a literature study was made to understand the mobile network, security vulnerabilities and existing countermeasures to achieve this. Thereon, a Stingray was constructed, and attacks were simulated with different settings and scenarios to determine their practical and effective use. The results show the possibility of Stingray attacks with the mentioned equipment, but underline the need for a more advanced system for real-world attacks. / Denna kandidatuppsats utforskar hotet från Stingrays, falska mobiltorn, på mobilnätet. Den ökande tillgängligheten av öppen-källkod teknologi och hårdvara har gjort det lättare att bygga Stingrays. Stingrays kan hota integriteten och säkerheten av individer och deras enheter, vilket gör det avgörande att förstå effektiviteten och praktikaliteter av attacken. Studiens mål är att utvärdera möjligheten och den praktiska faran med Stingrays genom att använda programvara med öppen källkod och tillgänglig hårdvara, vilket fyller en lucka i forskning inom ämnet. Först gjordes en litteraturstudie för att förstå mobila nätverket, säkerhetssårbarheter och befintliga motåtgärder för att uppnå detta. Därefter konstruerade vi en Stingray och simulerade attacker med olika inställningar och i olika scenarier för att avgöra deras praktiska och effektiva användning. Resultaten visar möjligheten av Stingray-attacker med den nämnda utrustningen men understryker behovet av ett mer advancerat system för verkliga attacker.

Made available in DSpace on 2015-04-22T22:12:46Z (GMT). No. of bitstreams: 1 Jefferson Lemos.pdf: 576722 bytes, checksum: a07c5844d483e717217e6bc8fd31e3fb (MD5) Previous issue date: 2011-06-01 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This work studied the parasite fauna and the health status of cururu stingray, Potamotrygon cf. hystrix, the middle Rio Negro, Amazonas, Brazil, during a hydrological cycle and stages of the extraction of ornamental fish (nature, post-transport, 48 hours in quarantine and 15 days of quarantine), through the identification and quantification of parasites and the correlation of parasite abundance with health indicators for fish. The parasitic index and health indicators were assessed in relation to water level and between stages. The health indicators used included the relative condition factor (Kn), the hepato somatic index (HSI), spleen (SSI) and epigonal organ (ISEO), and erythrocyte parameters and biochemical blood analysis. We found two species of Cestoda, unidentified specimens of Nematoda and Achantocephala, two species of Monogenoidea and five species of Branchiura. The Monogenoidea and Cestoda occurred in all periods of the hydrological cycle, the Nematoda and Branchiura not occurred at high water. The Acanthocephala were recorded during periods of drought and flood. The abundance of Cestoda positively correlated with the HSI, ISEO, hematocrit, erythrocyte number, hemoglobin and glucose. The abundance of Monogenoidea and Branchiura positively correlated with hematocrit and MCH, respectively. In the post-transport were observed critical values in dissolved oxygen and high ammonia levels in water. The Kn in nature was higher than post-transport, 48 hours in quarantine and 15 days of quarantine. The SSI and HSI were minor in nature. There was a reduction in red blood cells, hemoglobin and MCHC, and increased MCV, post-transport in relation to nature. In 48 hours and 15 days of quarantine, there was an increase in hemoglobin and MCH, besides the reduction in MCV in relation to post-transport. Glucose and total protein were lower in post-transport in relation to nature and 48 hours of quarantine, respectively. The Cestoda and Monogenoidea showed the highest prevalences in nature and post-transport. Cestoda abundance was higher in nature and post-transport in relation to 48 hours and 15 days of quarantine. Monogenoidea intensity was higher in post-transport than in other stages. It s the first seasonal study of parasites at a stingray of middle Rio Negro and pioneer in correlate the parasite abundance with health indicators in potamotrygonids. The post-transport was the most critical stage in the chain to the extractive cururu stingray. / Este trabalho estudou a fauna parasitária e o estado de saúde da arraia cururu, Potamotrygon cf. histrix, do médio Rio Negro, Amazonas, Brasil, durante um ciclo hidrológico e em etapas da cadeia extrativista de peixes ornamentais (natureza, pós-transporte, 48 horas de quarentena e 15 dias de quarentena), por meio da identificação e quantificação dos parasitos e a correlação da abundância parasitária com os indicadores de saúde para peixes. Os índices parasitários e os indicadores de saúde foram avaliados em relação ao nível hidrológico e entre as etapas citadas acima. Os indicadores de saúde utilizados incluíram o fator de condição relativo (Kn), a relação somática do fígado (RHS), baço (RES) e órgão epigonal (RSOE), além de parâmetros eritrocitários e da bioquímica do plasma. Foram encontradas duas espécies de Cestoda, espécimes não identificadas de Nematoda e Achantocephala, duas espécies de Monogenoidea e cinco espécies de Branchiura. Os Cestoda e Monogenoidea ocorreram em todos os períodos do ciclo hidrológico, os Nematoda e os Branchiura não ocorreram na vazante. Os Acanthocephala foram registrados nos períodos de seca e enchente. A abundância de Cestoda correlacionou positivamente com a RHS, RSOE, hematócrito, número de eritrócitos, níveis de hemoglobina e glicose. A abundância de Monogenoidea e Branchiura correlacionou positivamente com o hematócrito e o HCM, respectivamente. No pós-transporte observaram-se valores críticos no oxigênio dissolvido e níveis elevados de amônia na água. O Kn na natureza foi maior em relação ao pós- transporte, 48 horas de quarentena e 15 dias de quarentena. As RES e RHS foram menores na natureza. Houve redução no número de eritrócitos, concentração de hemoglobina e CHCM, além de aumento do VCM, no pós-transporte em relação à natureza. Em 48 horas e aos 15 dias de quarentena, houve aumento na hemoglobina e HCM, além de redução no VCM em relação ao póstransporte. Glicose e proteínas totais foram menores no pós-transporte em relação à natureza e 48 horas de quarentena, respectivamente. Os Cestoda e Monogenoidea apresentaram as prevalências mais elevadas na natureza e no pós-transporte. A abundância de Cestoda foi maior na natureza e no pós-transporte em relação às 48 horas e 15 dias de quarentena. A intensidade de Monogenoidea foi maior no pós-transporte que nas demais etapas. Este é o primeiro estudo sazonal de parasitos em uma arraia do médio Rio Negro e pioneiro ao correlacionar a abundância parasitária com indicadores de saúde em potamotrigonídeos. O pós-transporte foi a etapa mais crítica da cadeia extrativista para a arraia cururu.

The hearing abilities of elasmobranch fishes were examined in response to several types of stimuli using auditory evoked potentials (AEP). Audiograms were acquired for the nurse shark, Ginglymostoma cirratum, the yellow stingray, Urobatis jamaicensis, in a controlled environment using a monopole underwater speaker. A dipole stimulus was used to measure the hearing thresholds of the horn shark, Heterodontus francisi, and the white-spotted bamboo shark, Chiloscyllium plagiosum. The dipole experiments yielded much lower thresholds than any other experiment, suggesting that this type of sound specifically stimulated the macula neglecta by creating a strong velocity flow above the head of the shark. A shaker table was created to measure the directional hearing thresholds of the C. plagiosum and the brown-banded bamboo shark, C. punctatum. This experiment showed that these sharks could sense accelerations equally in all directions suggesting that they have omnidirectional ears. The results also yielded higher thresholds than with the dipole, suggesting that the macula neglecta was not stimulated as the sharks were being accelerated. An audiogram was also acquired for the Atlantic sharpnose shark, Rhizoprionodon terraenovae, using a monopole speaker in the field. This experiment revealed that the hearing thresholds did not appear to be masked by ambient noise levels, and resulting thresholds yielded the lowest levels detected by any elasmobranch using AEPs. Taken together, these experiments show that sharks are most sensitive to low frequency sounds in the near field and use both their otoconial endorgans as well as the macula neglecta to sense particle motion.

Although DNA repair capacity has been correlated with lifespan in terrestrial vertebrate species, it remains unknown how evolutionarily conserved the process is across all vertebrate taxa. In particular, chondrichthyan fishes have lifespans that range from 3-350 years and they are evolutionarily separated from modern humans Homo sapiens by approximately 400 million years. We hypothesized that chondrichthyan fishes would show significant homology in nuclear excision repair (NER) genes with humans, and that the expression of NER genes will correlate with the lifespan of the respective assessed species. For this study, DNA repair gene homology and expression was performed on the nurse shark Ginglymostoma cirratum (n=3) and yellow stingray Urobatis jamaicensis (n=3). The five main NER pathways were analyzed and compared to see the differences in both elasmobranch species, then compared with human foreskin fibroblast samples (n=3). RNA sequencing was used to determine the extent of gene expression in each species, comparing the read counts in each gene and comparing between the two species. The elephant shark Callorhinchus milii reference genome was used to align the nurse shark and yellow stingray samples. Homology of each gene of the NER pathways was assessed by the NCBI BLAST software. Results show that the MMR pathway has all the significant genes in higher frequencies in the nurse shark than in human. Within elasmobranchs in the five DNA repair pathways, the longer-lived species (nurse shark) has a significant higher gene expression than shorter-lived species (yellow stingray). Genes involved in the NER and BER pathways showed significantly lower expression in elasmobranch than in humans. However, there were significantly higher expression of more genes for the HR and MMR pathways in elasmobranchs than in humans.

Submitted by (edna.saturno@ufrpe.br) on 2017-02-23T13:49:46Z No. of bitstreams: 1 Ilka Siqueira Lima Branco Nunes.pdf: 2141818 bytes, checksum: 9aa7bf11d864f1e1ce580f338251fe3c (MD5) / Made available in DSpace on 2017-02-23T13:49:46Z (GMT). No. of bitstreams: 1 Ilka Siqueira Lima Branco Nunes.pdf: 2141818 bytes, checksum: 9aa7bf11d864f1e1ce580f338251fe3c (MD5) Previous issue date: 2015-05-29 / The south stingray is commonly captured as by-catch in different fisheries, not only in Brazil but also in some parts of South America, and due to the deficiency of available data, there is now a considerable deficit of information to evaluate the population status of the specie. In this context, the main goal of this study was to investigate aspects related to the ecology of the D. americana along the coast of the metropolitan area of Recife, from capture data and acoustic monitoring, and in the Biological Reserve of Atol das Rocas, from observation and movement analysis. On the coast of Recife CPUE´south stingray was higher in Boa Viagem / Piedade (0.33) than in Paiva (0.26). The average monthly CPUE on the beach of Boa Viagem / Piedade was higher in May, while on the beach of Paiva the highest value occurred in June. The annual CPUEs, to the beaches in combination, were higher at the research beginning in 2004 and 2005. Of the 85 specimens, it was possible to identify the sex in 17 animals, of which 16 were females, with DW ranging between 79.00 and 152.00 cm (124.63 ± 20.86), DL between 94.00 and 142.00 cm (113.08 ± 14.14), and TL between 97.00 and 255.00 cm (188.31 ± 54.97); and only one was male, with DW 87.00 cm. Throughout the research was also recorded the occurrence of a food item (Dasyatis marianae) unusual, never described before for D. american diet. The evaluation of the detection from the acoustic monitoring on the reef coastline, in relation to the 24 hour cycle indicated that the majority of the detections occurred over night (96.4%) (X² = 144.857; P <0.0001). The TAH values were higher in the years 2003 (0.76 ± 1.51) and 2008 (1.55 ± 1.76), observing, between 2009 (0.15 ± 0.42) and 2013 ( 0.21 ± 0.57), values consistently lower. The significant decrease of species sightings within the Rocas Atoll raised the possibility of there being a natural population decline in the region. The vertical habitat use pattern for the D. americana showed a strong preference for both tagged stingrays (91.4% and 86.3%, respectively) by hot water (above 28 ° C) and shallow (depths up to 5m) of Rocas Atoll over the monitoring period. The results showed that low depth areas as one of the essential habitats for specie inside to Rocas Atoll. Finally, it is essential that greater efforts are seeking in employees the continuation of an adequate monitoring of their populations in coastal and island waters. / A raia prego é comumente capturada como fauna acompanhante em diferentes pescarias, não apenas no Brasil mas também em grande parte da America do Sul, e devido à deficiência dos dados disponíveis, existe hoje um considerável déficit de informações que permitam avaliar o status populacional da espécie. Nesse contexto, o presente estudo teve como objetivo investigar aspectos relacionados à ecologia da D. americana, ao longo do litoral da região metropolitana do Recife, a partir de dados de captura e monitoramento acústico, e na Reserva Biológica do Atol das Rocas a partir de análises de avistagem e movimentação. No litoral de Recife a CPUE das raias prego foi maior em Boa viagem/Piedade (0,33) do que no Paiva (0,26). A CPUE média mensal na praia de Boa Viagem/Piedade foi maior no mês de maio, enquanto que na praia do Paiva o maior valor ocorreu em junho. As CPUEs anuais para as praias de forma combinada foram maiores no início da pesquisa, nos anos de 2004 e 2005. Dos 85 exemplares, foi possível a identificação do sexo em 17 animais, dos quais 16 eram fêmeas, com LD variando entre 79,00 e 152,00 cm (124,63 ± 20,86), CD entre 94,00 e 142,00 cm (113,08 ± 14,14), e CT entre 97,00 e 255,00 cm (188,31 ± 54,97); e apenas um era macho, com LD de 87,00 cm. Ao longo da pesquisa foi registrada ainda a ocorrência de um item alimentar (Dasyatis marianae) não usual, jamais antes descrito para dieta da D. americana. A avaliação das detecções do monitoramento acústico no litoral de Recife, em relação ao ciclo de 24 horas indicou que a maior parte das detecções ocorreram ao longo do período noturno (96,4%) (X²= 144,857; P< 0,0001). Os valores de TAH foram maiores entre os anos de 2003 (0,76 ± 1,51) e 2008 (1,55 ± 1,76), observando-se, entre 2009 (0,15 ± 0,42) e 2013 (0,21 ± 0,57), valores consistentemente mais baixos. A diminuição significativa das avistagens da espécie no interior do Atol das Rocas suscita a possibilidade de estar existindo um declínio natural da população na região. O padrão de uso do habitat vertical para a D. americana mostrou uma forte preferência, para ambas as raias marcadas (91,4% e 86,3%, respectivamente), pelas águas quentes (acima dos 28°C) e rasas (profundidades de até 5m) do Atol das Rocas, ao longo do período do monitoramento. Os resultados evidenciaram que as áreas de baixa profundidade como um dos habitas essenciais para espécie no Atol das Rocas. Por fim, é imprescindível que maiores esforços sejam empregados em busca da continuação de um adequado monitoramento de suas populações em águas costeiras e insulares.