Thesis (M.S.)--University of West Florida, 2008. / Title from title page of source document. Document formatted into pages; contains 0 pages. Includes bibliographical references.

Thirteen elasmobranch species were collected during a four year seine-net survey of the intertidal margins of Moreton Bay, a large subtropical embayment in southeast Queensland, Australia. The inshore elasmobranch fauna of Moreton Bay is relatively species rich in comparison to sites elsewhere in Australia, emphasising the regional importance of this ecosystem. Stingrays were the most common large predators in the intertidal, with overall catches dominated numerically by the blue-spotted maskray Neotrygon kuhlii (53.8%) and the estuary stingray Dasyatis fluviorum (22.2%). The biological and demographic characteristics of these two species were examined in detail. Neotrygon kuhlii ranged in size from 11.5 – 46.5 cm disc width (WD), with 50% maturity in females at 31.4 cm WD and 6.32 years old and at 29.4 cm WD and 3.95 years in males. Neotrygon kuhlii has a synchronous annual reproductive cycle, producing one litter of 1 – 3 pups (mean of 1.67 ± 0.71 S.D.) in the late Austral summer after a four month gestation. Maximum age estimates of 13 and 10 years were obtained from females and male N. kuhlii, respectively. Annual band pair deposition was confirmed through the recapture of four wild calcein-injected individuals from 22.7 to 30.2 cm WD. A three parameter power function provided the best statistical fit to age-at-size data for both sexes, providing parameter estimates of y0 = 163.13, a = 58.52 and b = 0.58 for females and y0 = 165.13, a = 59.02 and b = 0.54 in males. Individual growth rates obtained from tagged specimens were not qualitatively different to modelled growth predictions. Tagging studies produced a total recapture rate of 16.1%, with individual rays at liberty for up to 1081 days. Direct estimates of instantaneous mortality for N. kuhlii were derived by creating catch curves for both sexes from age-frequency keys. Mortality was estimated at 0.171 ± 0.024.yr-1 S.E. in females, corresponding with a population growth rate of 1.00.yr-1 based on deterministic matrix demographic model predictions, and 0.345 ± 0.022.yr-1 S.E. in males. Seven age-independent and two age-dependent indirect mortality estimates produced negative population growth rates of 0.84 to 0.98.yr-1. Elasticity results were relatively robust to mortality estimates, with juvenile survivorship contributing 74-75% of total elasticity under all scenarios. Dasyatis fluviorum is endemic to near-shore, estuarine and riverine habitats along the eastern coast of Australia. Previous records of the species from northern Australia and New Guinea appear to be misidentifications of other, similar species. Dasyatis fluviorum was caught at 15.5 cm to 76.2 cm WD in Moreton Bay, with 50% maturity occurring at 63 cm WD (13.40 years) in females and 41.2 cm WD (6.97 years) in males. Maximum age estimates of 21 and 16 years were obtained from females and males, respectively. The Gompertz growth function provided the best fit to estimated age data in female D. fluviorum, providing parameter estimates of WD∞ = 100.3 cm, k = 0.09.yr-1 and t0 = 5.66. The modified two-parameter von Bertalanffy growth function provided the best fit to male size-at-age data, providing parameter estimates of WD∞ = 73.4 cm, k = 0.10.yr-1 and b = 0.86. An annual reproductive cycle in female D. fluviorum was hypothesised based on preliminary reproductive data. Fecundity estimates were derived from the related D. americana for input into deterministic and stochastic demographic models. Six out of nine indirect mortality estimates produced positive population growth in deterministic models, with a probabilistic estimate of 1.02.yr-1. Elasticity results were robust to model structure, mortality and fecundity estimates, with juvenile survivorship comprising 74-78% of total elasticity under all scenarios. Both N. kuhlii and D. fluviorum provide interesting case studies in elasmobranch conservation. Neotrygon kuhlii is a common bycatch of demersal prawn-trawl fisheries in Australia. Although mandatory turtle exclusion devices (TEDs) exclude most large vertebrates from trawl catches in Australian waters, their benefits in the reduction of smaller elasmobranch bycatch has not been empirically tested. The results of deterministic demographic models show that TEDs can, in principle, mitigate the impacts of trawl fisheries by partially excluding highly-elastic large juvenile age-classes. However, N. kuhlii is the largest of the four Neotrygon species found in Australian waters and bycatch of the three smaller species may be less reduced by current bycatch reduction technologies. Dasyatis fluviorum is affected by a suite of anthropogenic threats in its near-shore and estuarine habitats including commercial and recreational fisheries, habitat modification and pollution. Within Moreton Bay, 10.8% of the surveyed population bore evidence of past interactions with fisheries as evidenced by retained hooks or mutilated tails. Deep-hooking resulted in significant pathological effects including fibrocollagenous scar tissue masses, peritonitis and hepatitis. Stochastic demographic scenarios were created to model the potential effects of low (0.02 yr-1), medium (0.05 yr-1) and high (0.10 yr-1) rates of additive anthropogenic mortality to simulate stage-specific conservation interventions on D. fluviorum. Removing anthropogenic mortality on juvenile age-classes provided the largest benefits in terms of reducing population decline. The probability of the species’ conservation status declining further to Endangered, based on IUCN criteria, ranged from 39% to 100% under these mortality scenarios if no conservation measures were applied.

Thirteen elasmobranch species were collected during a four year seine-net survey of the intertidal margins of Moreton Bay, a large subtropical embayment in southeast Queensland, Australia. The inshore elasmobranch fauna of Moreton Bay is relatively species rich in comparison to sites elsewhere in Australia, emphasising the regional importance of this ecosystem. Stingrays were the most common large predators in the intertidal, with overall catches dominated numerically by the blue-spotted maskray Neotrygon kuhlii (53.8%) and the estuary stingray Dasyatis fluviorum (22.2%). The biological and demographic characteristics of these two species were examined in detail. Neotrygon kuhlii ranged in size from 11.5 – 46.5 cm disc width (WD), with 50% maturity in females at 31.4 cm WD and 6.32 years old and at 29.4 cm WD and 3.95 years in males. Neotrygon kuhlii has a synchronous annual reproductive cycle, producing one litter of 1 – 3 pups (mean of 1.67 ± 0.71 S.D.) in the late Austral summer after a four month gestation. Maximum age estimates of 13 and 10 years were obtained from females and male N. kuhlii, respectively. Annual band pair deposition was confirmed through the recapture of four wild calcein-injected individuals from 22.7 to 30.2 cm WD. A three parameter power function provided the best statistical fit to age-at-size data for both sexes, providing parameter estimates of y0 = 163.13, a = 58.52 and b = 0.58 for females and y0 = 165.13, a = 59.02 and b = 0.54 in males. Individual growth rates obtained from tagged specimens were not qualitatively different to modelled growth predictions. Tagging studies produced a total recapture rate of 16.1%, with individual rays at liberty for up to 1081 days. Direct estimates of instantaneous mortality for N. kuhlii were derived by creating catch curves for both sexes from age-frequency keys. Mortality was estimated at 0.171 ± 0.024.yr-1 S.E. in females, corresponding with a population growth rate of 1.00.yr-1 based on deterministic matrix demographic model predictions, and 0.345 ± 0.022.yr-1 S.E. in males. Seven age-independent and two age-dependent indirect mortality estimates produced negative population growth rates of 0.84 to 0.98.yr-1. Elasticity results were relatively robust to mortality estimates, with juvenile survivorship contributing 74-75% of total elasticity under all scenarios. Dasyatis fluviorum is endemic to near-shore, estuarine and riverine habitats along the eastern coast of Australia. Previous records of the species from northern Australia and New Guinea appear to be misidentifications of other, similar species. Dasyatis fluviorum was caught at 15.5 cm to 76.2 cm WD in Moreton Bay, with 50% maturity occurring at 63 cm WD (13.40 years) in females and 41.2 cm WD (6.97 years) in males. Maximum age estimates of 21 and 16 years were obtained from females and males, respectively. The Gompertz growth function provided the best fit to estimated age data in female D. fluviorum, providing parameter estimates of WD∞ = 100.3 cm, k = 0.09.yr-1 and t0 = 5.66. The modified two-parameter von Bertalanffy growth function provided the best fit to male size-at-age data, providing parameter estimates of WD∞ = 73.4 cm, k = 0.10.yr-1 and b = 0.86. An annual reproductive cycle in female D. fluviorum was hypothesised based on preliminary reproductive data. Fecundity estimates were derived from the related D. americana for input into deterministic and stochastic demographic models. Six out of nine indirect mortality estimates produced positive population growth in deterministic models, with a probabilistic estimate of 1.02.yr-1. Elasticity results were robust to model structure, mortality and fecundity estimates, with juvenile survivorship comprising 74-78% of total elasticity under all scenarios. Both N. kuhlii and D. fluviorum provide interesting case studies in elasmobranch conservation. Neotrygon kuhlii is a common bycatch of demersal prawn-trawl fisheries in Australia. Although mandatory turtle exclusion devices (TEDs) exclude most large vertebrates from trawl catches in Australian waters, their benefits in the reduction of smaller elasmobranch bycatch has not been empirically tested. The results of deterministic demographic models show that TEDs can, in principle, mitigate the impacts of trawl fisheries by partially excluding highly-elastic large juvenile age-classes. However, N. kuhlii is the largest of the four Neotrygon species found in Australian waters and bycatch of the three smaller species may be less reduced by current bycatch reduction technologies. Dasyatis fluviorum is affected by a suite of anthropogenic threats in its near-shore and estuarine habitats including commercial and recreational fisheries, habitat modification and pollution. Within Moreton Bay, 10.8% of the surveyed population bore evidence of past interactions with fisheries as evidenced by retained hooks or mutilated tails. Deep-hooking resulted in significant pathological effects including fibrocollagenous scar tissue masses, peritonitis and hepatitis. Stochastic demographic scenarios were created to model the potential effects of low (0.02 yr-1), medium (0.05 yr-1) and high (0.10 yr-1) rates of additive anthropogenic mortality to simulate stage-specific conservation interventions on D. fluviorum. Removing anthropogenic mortality on juvenile age-classes provided the largest benefits in terms of reducing population decline. The probability of the species’ conservation status declining further to Endangered, based on IUCN criteria, ranged from 39% to 100% under these mortality scenarios if no conservation measures were applied.

Chondrichthyans are cartilaginous fishes that include the extant chimaeras, sharks, and batoids, and their extinct relatives. In this dissertation, I examined the growth, development, and relationships of extinct and extant chondrichthyans. I reexamined the skeleton of fossil and fetal specimens of the angel sharks (Squatiniformes) and reanalyzed the current morphologically based hypothesis of chondrichthyan evolution, which conflicts with the current molecular based hypothesis. I did this by including extinct taxa and new characters based on dentition, and the ethmoid, occipital, pectoral, and vertebral skeleton. My results supported the pre-existing morphological hypothesis that angel sharks, saw sharks, and batoids form a clade. However, some of my new characters, particularly those based on the vertebral morphology, indicate that fetal and juvenile angel sharks do not share as many apomorphies with batoids as previously hypothesized from the examination of adults. I also examine the relationships of major groups within batoids, beginning with the construction of a hypothesis of the evolutionary history of electric rays (Torpediniformes). My results are consistent with previous rank-based classifications. However, they deviate from previous classifications depending on the criteria used to generate the hypothesis and on which taxon, or combination of taxa, were used to root the ingroup phylogeny. Because pectoral and vertebral morphology are so critical to morphological hypotheses, I also examined the growth and development of the synarcual cartilage in batoid fishes, with particular emphasis on the synarcual of skates (Rajiformes). My results demonstrate that calcification and chondrification do not proceed in the same order, temporally and spatially. Finally, I redescribe the extinct batoid †Cyclobatis, known only from the Cretaceous, and evaluate its phylogenetic position. My results indicate that †Cyclobatis, the oldest known rajid, is also the sister taxon to a clade of all known extant members of Rajidae. Furthermore, the inclusion of new characters, mainly derived from the synarcual, help to resolve the interrelationships of Rajidae. / text

Crude oil causes both lethal and sublethal effects on marine organisms, but the impact upon sensory function remains unexplored. Elasmobranchs rely upon the effective functioning of their sensory systems for use in feeding, mating, and predator avoidance. The objective of this study was to test the effect of crude oil upon the olfactory and electroreceptive sensitivity of the Atlantic stingray, Dasyatis sabina. The magnitudes of the electro-olfactogram (EOG) responses were significantly depressed by 26% (Glutamic Acid) to 157% (Cysteine) for all amino acids when stingrays were exposed to crude oil. The shapes of the EOG responses when exposed to oil were also significantly different, exhibiting a more protracted response compared to un-exposed stingrays. Oil exposed stingrays exhibited a significant decrease in orientation distance to prey-simulating electric fields. This study is the first to quantify the effects of crude oil on olfactory and electrosensory sensitivity of marine predators. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2016. / FAU Electronic Theses and Dissertations Collection

Made available in DSpace on 2015-04-11T13:54:58Z (GMT). No. of bitstreams: 1 juliana luiza.pdf: 3875282 bytes, checksum: e88fed331ab492bec9b53ea5c76c15f5 (MD5) Previous issue date: 2013-05-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Accidents caused by freshwater stingrays are characterized by intense pain and pathological changes at the lesion site, which include edema, erythema and, in most cases, necrosis. In this study, mucus and tissue extracts from the dorsal region and sting of freshwater stingrays Potamotrygon motoro and Plesiotrygon iwamae were analyzed by electrophoresis on SDS-PAGE and zymography. The myotoxic activity (local and systemic) induced by extracts in murine model was evaluated by morphometric analysis and enzimatic activity of the phospholipase A2 (indirect hemolysis) in agarose gel. P. motorosting extract showed a diffuse band with 10 kDa, several between 58 and 27 kDa, and proteolytic components above 58 kDa, while the dorsal region extract showed a strong and diffuse band around 41 kDa and a proteolytic component with 6 kDa. P. iwamae showed, in all samples, a diffuse and intense band with 15 kDa and proteolytic components around 6 and 40 kDa. Doses of 140 μg of P. iwamae protein extracts (sting and dorsal region) induced indirect hemolysis after 24 and 48 hours, but the halo diameter was below 10 mm (minimum value set for the technical), showing a weak phospholipase A2activity. Coagulative necrosis of the muscle tissue, muscle fiber regeneration and inflammatory infiltrates, including neutrophils, macrophages and a reduced number of eosinophils and lymphocytes were observed 24 hours after injection of 400 μg of P. motoro and P. iwamae mucus extracts in mice gastrocnemius muscle. These results were also observed, in a lower proportion, in the gastrocnemius muscles of the contralateral legs, showing that extracts of both species were able to induce a systemic rhabdomyolysis when tested in BALB/c mice. / Acidentes por arraias de água doce são caracterizados por dor intensa e alterações patológicas no local da lesão, que incluem edema, eritema e, na maioria dos casos, necrose. Nesta pesquisa, os extratos de muco e tecido do dorso e do ferrão das arraias Plesiotrygon iwamae e Potamotrygon motoro foram analisados por eletroforese em SDS-PAGE e por zimografia. A atividade miotóxica (local e sistêmica) induzida pelos extratos, em modelo murino, foi avaliada por histopatologia e a atividade da enzima fosfolipase A2 (hemólise indireta), em gel de agarose. O extrato do ferrão de P. motoro apresentou uma banda difusa de 10 kDa, várias entre 58 e 27 kDa e componentes proteolíticos acima de 58 kDa, enquanto que o extrato do dorso apresentou uma banda forte difusa com cerca de 41 kDa e um componente proteolítico de 6 kDa. Em P. iwamae, todas as amostras apresentaram uma banda intensa e difusa de 15 kDa e componentes proteolíticos de 6 e 40 kDa. As doses de 140 μg de proteína dos extratos de P. iwamae induziram hemólise indireta nos intervalos de tempo de 24 e 48 horas, porém, não formaram o halo de 10 mm de diâmetro (valor mínimo definido para a técnica), demonstrando uma fraca atividade de fosfolipase A2. Necrose coagulativa do tecido muscular, regeneração das fibras musculares e presença de infiltrados inflamatórios, incluindo neutrófilos, macrófagos, e um número reduzido de eosinófilos e linfócitos foram observados 24 horas após a injeção da dose de 400 μg dos extratos de muco do dorso e do ferrão das arraias P. motoro e P. iwamae no músculo gastrocnêmio dos camundongos. Tais resultados também foram observados, em menor volume, nos músculos gastrocnêmios das patas contralaterais, demonstrando que os extratos das duas espécies foram capazes de induzir a uma rabdomiólise sistêmica quando testados em camundongos BALB/c.

Made available in DSpace on 2015-04-22T22:17:31Z (GMT). No. of bitstreams: 1 DISSERTACAO - WALACE BATISTA.PDF: 1407845 bytes, checksum: f0b36df932039802563ad55fc19ae923 (MD5) Previous issue date: 2008-03-31 / Fundação de Amparo à Pesquisa do Estado do Amazonas / The fish as food is a major source of high-quality protein, with a balance of essential amino acids, and the quality of lipids, great source of polyunsaturated fatty acids. Over the years the fish has been the principal source of nutrients of animal origin in the Amazon and exploitation of fishery resources in a rational way is one of the major challenges to the industry, regional beneficiary eligibility of fish. The freshwater stingrays of gender Potamotrygon and Paratrygon come in over the past five years by participating systematically landing fishing in the Amazon region, so much so that currently fishing fleets are especially equipped to perform the capture of stingrays. However, all this effort is being applied without information on the technological characteristics of the species, which could subsidize decisions on methods and processes. Therefore, the purpose of this study was to characterize technology and the profile of fatty acids of the species Paratrygon aiereba and Potamotrygon motoro aiming to contribute to a better utilization of industrial species and subsidize the formulation of diets. The two copies of freshwater stingrays had a good income meat of pectoral fin, with 35.12% for P. aiereba and 32.35% P. motoro. Data from proximate composition were close to those established for other species of fish, featuring the two species of stingrays as leanness (<1% fat). The profile of fatty acids indicated as the majority arachidonic acid (20: 4n-6) and palmitic (16: 0). The indices of arachidonic acid obtained in the two species was respectively 29.16% in individuals of P. Motoro collected in the period of flooding in the lake of Moreno Maia and 21.17% in individuals of P. Aiereba collected in the period of drought in the Purus river. / O pescado como alimento é uma das principais fontes de proteínas de alta qualidade, com um balanceamento de aminoácidos essenciais, além da qualidade dos lipídeos, grande fonte de ácidos graxos poliinsaturados. Ao longo dos anos o pescado tem sido a principal fonte de nutrientes de origem animal na Amazônia e o aproveitamento dos recursos pesqueiros de forma racional é um dos grandes desafios à indústria de beneficiamento do pescado regional. As arraias do gênero Potamotrygon e Paratrygon vêm nos últimos 5 anos participando sistematicamente do desembarque pesqueiro na região amazônica, tanto assim que atualmente frotas pesqueiras estão equipadas especialmente para efetuar a captura de arraias. Entretanto, todo esse esforço vem sendo aplicado sem informações relativas às características tecnológicas das espécies, que poderiam subsidiar decisões em métodos e processos. Neste sentido, a proposta deste trabalho foi realizar a caracterização tecnológica e o perfil de ácidos graxos das espécies Paratrygon aiereba e Potamotrygon motoro visando contribuir para um melhor aproveitamento industrial das espéciese subsidiar a formulação de dietas. Os dois exemplares de arraia apresentaram um bom rendimento cárneo das nadadeiras peitorais, com 35,12% para P. aiereba e 32,35% P. motoro. Os dados de composição centesimal ficaram próximos aos estabelecidos para outras espécies de peixes, caracterizando as duas espécies de arraias como magras (<1% de gordura). O perfil de ácidos graxos indicou como majoritários os ácidos araquidônico (20:4n-6) e palmítico (16:0). Os índices de ácido araquidônico obtidos nas duas espécies foi respectivamente 29,16% em indivíduos de P. motoro coletados no período de enchente no lago do Moreno Maia e 21,17% em indivíduos de P. aiereba coletados no período da seca no rio Purus.

Submitted by FABIANA DA SILVA FRANÇA (fabiana21franca@gmail.com) on 2018-02-23T17:33:04Z No. of bitstreams: 1 Arquivo Total.pdf: 2718770 bytes, checksum: 9378d34888dfcacdd356cf58ac71eaa8 (MD5) / Made available in DSpace on 2018-02-23T17:33:04Z (GMT). No. of bitstreams: 1 Arquivo Total.pdf: 2718770 bytes, checksum: 9378d34888dfcacdd356cf58ac71eaa8 (MD5) Previous issue date: 2017-03-22 / The Rufford Foundation / Understanding the ecological role of species within an ecosystem depends largely on knowledge of its trophic relations. Such relations and the position of species within a foodweb are a central step in understanding the dynamics of the communities and the impacts that each species has on the trophic network compartments. The knowledge on the diet of the South American freshwater stingrays has increased considerably over the last years,but still, little is know about their ecological role. Thereby, the aim of this research is to evaluate the importance of the stingray Potamotrygon magdalenae in the structure of a freshwater food web. The feeding habits and the trophic ecology of this species were evaluated using stomach content analysis in combination with stable isotopes of carbon and nitrogen from samples collected in the middle Magdalena river basin, Colombia, and its ecological importance from topological analyzes of trophic networks. Potamotrygon magdalenae showed a specialized diet, feeding primarily on insects. No significant differences of δ13C and δ15N were observed in the muscle of the species between the hydrological periods of high and low waters. The species isotopic niche was intermediate. In terms of ecological importance, it played an intermediary role in the dispersion of indirect effects through the system, due to its intermediate values of centrality and topological importance. These results provide a starting point for further ecological studies about the South American freshwater stingray species, in order to assess their role in the ecosystem. On the other hand, theycomplement the existing studies of Potamotrygon magdalenae. / Compreender o papel ecológico das espécies no ecossistema depende amplamente do conhecimento de suas relações tróficas. Conhecer tais relações e a posição das espécies em umarede é um passo crucial para entender a dinâmica das comunidades e os impactos quecada espécie tem sobre os demais compartimentos. Oconhecimento sobre adieta das espécies de raias de água doce de América do Sul tem aumentado consideravelmente ao longo dos últimos anos, porém, é muito pouco o que se sabe sobre o papel ecológico das espécies nos seus respectivos ecossistemas. Assim, oobjetivo deste trabalho foi avaliar a importânciaecológica da raia Potamotrygon magdalenae na estrutura da rede trófica de um ecossistema de águas continentais. Foram avaliados os hábitos alimentares e a ecologia trófica da espécie através da análise de conteúdos estomacais e isótopos estáveis de carbono e nitrogênio a partir de amostras coletadas na bacia do médio rio Magdalena, Colômbia; e sua importância ecológica a partir de análises topológicas de redes tróficas. A espécie foi considerada um predador especialista de nível trófico intermediário, com preferência pelos insetos.Não foram observadas diferenças significativas de δ13C e δ15N na espécie entre os períodos hidrológicos de cheia e de águas baixas. O seu nicho isotópico foi intermediário. Em relação à importância ecológica, a espécie desempenhou um papel intermediário na dispersão de efeitos indiretos através do sistema, devido aos seus valores intermediários de centralidade e importância topológica. Estes resultadosconstituem um ponto de partida para novos estudos ecológicos das espécies de raias de água doce da América do Sul, que visem avaliar seu papel nos ecossistemas, e complementam os estudos existentes de Potamotrygon magdalenae.