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Elasmobranchs play ecologically important roles in coastal environments. Unfortunately, the basic distribution and movement patterns of these species, particularly rays, remain relatively unknown. This is especially true for the Whitespotted Eagle Ray (Aetobatus narinari), a protected species in Florida with poorly described migratory and habitat use patterns. I employed a combination of acoustic telemetry techniques to reveal multi-scale spatial patterns of A. narinari around Florida. Movement patterns between the east and west coast individuals were distinct; a majority of west coast tagged A. narinari exhibited migratory or transient behavior while most east coast tagged individuals remained resident in the Indian River Lagoon. Fine-scale tracking of A. narinari revealed individuals spent a large percentage of time in the inlets and channels and frequently reused habitats parallel to the shore. This study fills a knowledge gap on the species ecology which may be used for adaptive management strategies throughout A. narinari’s range. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection

The central importance of vision to an organism is evident in the anatomical and physiological adaptations within the eye that can be correlated to the organism's behavior and ecology. The goal of this study was to perform a functional analysis of adaptations within the elasmobranch visual system. An integrative approach was used to examine morphological and physiological adaptations in several species and link these adaptations to phylogeny, locomotion, habitat, behavior and ecology. Functional aspects investigated were eye position, pupil shape, spectral sensitivity, temporal resolution, the extent of the visual field and ultimately the integration of the visual and electrosensory systems. The elasmobranch eye adapts to the light environment of its habitat. Sharks from similar habitats had similar spectral sensitivities such as the bonnethead and blacknose sharks, both maximally sensitive to blue light of 480 nm. The spectral sensitivity of the scalloped hammerhead, which lives in a different environment, was maximally sensitive to green light (530 nm). The temporal characteristics of the eye also matched habitat and lifestyle. Species experiencing variable light conditions exhibited increased critical flicker-fusion frequencies, such as the bonnethead (31 Hz) and scalloped hammerhead (27 Hz), in contrast to deeper or more nocturnal species such as the blacknose shark (18 Hz). Elasmobranch visual fields correlated to each species' lifestyle, habitat and foraging strategy. Expansive monocular views, including a 360° panoramic view in the yellow stingray, were measured in species that rely on vision for vigilance against predators. / The Atlantic stingray possessed large binocular overlaps (72°), which provided depth perception useful for tracking prey. By comparison, the frontal binocular overlaps of hammerhead species were larger than sharks with a more conventional head shape.This study quantified the range of the electrosensory system and the exte the visual field of several shark species, confirming both systems overlap around the head facilitating near seamless visual and electrosensory sensory function relevant to prey detection. The findings of this study indicate that ambient environmental light strongly influenced the function of the elasmobranch eye and that the extent of species' visual fields correlated with aspects of their morphology, locomotion and ecology. / by Dawn Michelle McComb. / Thesis (Ph.D.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

As estruturas com maior possibilidade de fossilização do esqueleto dos Chondrichthyes são aquelas mais mineralizadas, tais como dentes, escamas, espinhos cefálicos e de nadadeiras. Na Formação Rio do Rasto, os Chondrichthyes estão representados predominantemente por dentes e espinhos de nadadeiras. Na presente dissertação, foram estudados espécimes coletados em um afloramento do Membro Serrinha da Formação Rio do Rasto próximo ao quilômetro 20 da BR-153 no Município de Jacarezinho, Estado do Paraná, Brasil. O material corresponde a dois conjuntos, um representado por dois espinhos de nadadeira e o outro por vários dentes, todos depositados no Museu de Ciências Naturais do Setor de Ciências Biológicas da Universidade Federal do Paraná. No primeiro conjunto as características apresentadas pelos espinhos permitiram atribuí-los a uma nova espécie de Sphenacanthidae, enquanto que as características do segundo conjunto permitiram atribuir os dentes a uma nova espécie de Xenacanthidae. A associação fóssil na localidade-tipo e no mesmo horizonte estratigráfico da Formação Rio do Rasto indica que estas ocorrências de tubarões podem representar mais um registro de água doce para os xenacantídeos e esfenacantídeos. / The chondrichthian skeletal structures with greater potential of fossilization are the most mineralized such as teeth, scales, fin spines and cephalic spines. In the Rio do Rasto Formation the Chondrichthyes are represented by fin spines and teeth. The studied material came from an outcrop of Serrinha Member of the Rio do Rasto Formation, close to km 20, by the road BR-153 in the city of Jacarezinho, State of Paraná, Brazil. The studied material are two sets, one represented by two fin spines and the other by several teeth, all housed in the “Museu de Ciências Naturais do Setor de Ciências Biológicas da Universidade Federal do Paraná” - UFPR Natural Sciences Museum. In the first set, the features shown allow to ascribe the finspines to a new species of Sphenacanthidae, while the features of the second set allow to ascribe the teeth a new species of Xenacanthidae. The fossil association in the type locality and in the same stratigraphical horizon in the Rio do Rasto Formation indicates that these shark occurrences could represent another freshwater record for the xenacanthids and sphenacanthids.

In the summer of 1997, 217 fishes of different species (Raja erinacea, R. radiata, R. ocellata, Malacoraja senta, and Squalus acanthias) were collected from the West Isles of the Bay of Fundy, New Brunswick. / Parasites belonging to 13 species were found: 10 Cestoda; 2 Nematoda; and 1 Acanthocephala. Of the 10 cestodes, five are described as new species. The remaining five re-described in detail and compared to similar worms reported in the literature. None of the eight tetraphyllidean cestodes was found in more than one host species, thereby supporting current dogma that the Tetraphyllidea are species specific with respect to their definitive hosts. / There is a close relationship between the topography of the spiral-valve mucosa of the preferred attachment-site and that of the inner-bothridial tegument. This provides further evidence supporting the strict morphological specificity proposed by Williams (1960).

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.

Submitted by Alberto Vieira (martins_vieira@ibest.com.br) on 2018-01-12T20:14:53Z No. of bitstreams: 1 542803.pdf: 14910345 bytes, checksum: 5018a3eea3a8fe15263592b5816521bb (MD5) / Made available in DSpace on 2018-01-12T20:14:53Z (GMT). No. of bitstreams: 1 542803.pdf: 14910345 bytes, checksum: 5018a3eea3a8fe15263592b5816521bb (MD5) Previous issue date: 2001-04-27 / O gênero Psammobatis Günther, 1870 é endêmico da América do Sul, estando representado nas duas costas do continente. Foi revisado por McEACHRAN (1983), que dividiu o gênero em dois subgrupos monofiléticos. O subgrupo I composto por P. bergi Marini, 1932; P. glansdissimilis McEachran, 1983; P. lentiginosa McEachran, 1983 e P. rutrum Jordan, 1890, inclui espécies que ocorrem na plataforma continental do sudeste/sul do Brasil, Uruguai e norte da Argentina. O subgrupo II é formado por P. normani McEachran, 1983; P. parvacauda McEachran, 1983; P. rudis Günther, 1870 e P. scobina (Philippi, 1857), cuja área de distribuição se restringe a plataforma continental sul da Argentina e Chile, no Pacífico Leste meridional. Erros na identificação das espécies do subgrupo I de McEACHRAN (1983) são freqüentes, principalmente entre indivíduos de P. extenta e P. rutrum. Essas duas espécies são muito semelhantes entre si e sua distinção, em adultos, se faz pela presença de aguilhões na margem do sulco espermático dos mixopterígios. Como este caráter não pode ser observado em machos jovens e fêmeas, a identificação de exemplares destas espécies é geralmente problemática. Problemas relativos à identificação das espécies do subgrupo I de McEACHRAN (1983) foram revistos e novos caracteres foram definidos de modo a possibilitar a identificação por meio de caracteres externos. Uma chave de identificação para as espécies do subgrupo foi elaborada com base nos caracteres revelados, de modo a viabilizar a identificação de indivíduos adultos e jovens, de ambos os sexos, inclusive no campo. / The genus Psammobatis Günther, 1870 is a South American endemic represented in both the Atlantic and Pacific coasts of the continent. It has been recently reviewed by McEACHRAN (1983), who divided the genus in two monophyletic groups. Subgroup I, composed of P. bergi Marini, 1932; P. glansdissimilis McEachran, 1983; P. lentiginosa McEachran, 1983 and P. rutrum Jordan, 1890 includes species which occur off the coast of southeastern/southern Brazil, Uruguay and northern Argentina. Subgroup II is formed by P. normani McEachran, 1983; P. parvacauda McEachran, 1983; P. rudis Günther, 1870 and P. scobina (Philippi, 1857), the distribution of which is restricted to shelf waters off the southern coasts of Argentina and Chile, the latter in the eastern South Pacifíc. Misidentifications among species of subgroup I are frequent, particularly between individuals of P. extenta and P. rutrum. These two species are remarkably similar, the separation of adult specimens being nevertheless possible by the presence of thorns in the spermatic duct of the mixopterygia. Since this character can not be observed in young males and females, the identification of specimens of the above species is often problematical. Problems related to the identification of the species included in subgroup I of McEACHRAN (1983) were reviewed, and new characters were defined in order to turn practical the separation of the four species of the subgroup by means of the examination of external characters. An identification key for the species of the subgroup based on external characters is presented, and its use turns possible the ready identification of young and adults of both sexes, both in the laboratory or in the field.

As estruturas com maior possibilidade de fossilização do esqueleto dos Chondrichthyes são aquelas mais mineralizadas, tais como dentes, escamas, espinhos cefálicos e de nadadeiras. Na Formação Rio do Rasto, os Chondrichthyes estão representados predominantemente por dentes e espinhos de nadadeiras. Na presente dissertação, foram estudados espécimes coletados em um afloramento do Membro Serrinha da Formação Rio do Rasto próximo ao quilômetro 20 da BR-153 no Município de Jacarezinho, Estado do Paraná, Brasil. O material corresponde a dois conjuntos, um representado por dois espinhos de nadadeira e o outro por vários dentes, todos depositados no Museu de Ciências Naturais do Setor de Ciências Biológicas da Universidade Federal do Paraná. No primeiro conjunto as características apresentadas pelos espinhos permitiram atribuí-los a uma nova espécie de Sphenacanthidae, enquanto que as características do segundo conjunto permitiram atribuir os dentes a uma nova espécie de Xenacanthidae. A associação fóssil na localidade-tipo e no mesmo horizonte estratigráfico da Formação Rio do Rasto indica que estas ocorrências de tubarões podem representar mais um registro de água doce para os xenacantídeos e esfenacantídeos. / The chondrichthian skeletal structures with greater potential of fossilization are the most mineralized such as teeth, scales, fin spines and cephalic spines. In the Rio do Rasto Formation the Chondrichthyes are represented by fin spines and teeth. The studied material came from an outcrop of Serrinha Member of the Rio do Rasto Formation, close to km 20, by the road BR-153 in the city of Jacarezinho, State of Paraná, Brazil. The studied material are two sets, one represented by two fin spines and the other by several teeth, all housed in the “Museu de Ciências Naturais do Setor de Ciências Biológicas da Universidade Federal do Paraná” - UFPR Natural Sciences Museum. In the first set, the features shown allow to ascribe the finspines to a new species of Sphenacanthidae, while the features of the second set allow to ascribe the teeth a new species of Xenacanthidae. The fossil association in the type locality and in the same stratigraphical horizon in the Rio do Rasto Formation indicates that these shark occurrences could represent another freshwater record for the xenacanthids and sphenacanthids.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-05-10T23:18:28Z No. of bitstreams: 1 NataliaDeMedeirosPires_DISSERT.pdf: 917109 bytes, checksum: 272238860ade20f735d3f852b26b43ff (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-05-18T20:01:54Z (GMT) No. of bitstreams: 1 NataliaDeMedeirosPires_DISSERT.pdf: 917109 bytes, checksum: 272238860ade20f735d3f852b26b43ff (MD5) / Made available in DSpace on 2016-05-18T20:01:54Z (GMT). No. of bitstreams: 1 NataliaDeMedeirosPires_DISSERT.pdf: 917109 bytes, checksum: 272238860ade20f735d3f852b26b43ff (MD5) Previous issue date: 2015-02-24 / Beyond its importance in maintaining ecosystems, sharks provide services that play important socioeconomic roles. The rise in their exploitation as a tourism resource in recent years has highlighted economic potential of non-destructive uses of sharks and the extent of economic losses associated to declines in their population. In this work, we present estimates for use value of sharks in Fernando de Noronha Island - the only ecotouristic site offering shark diving experience in the Atlantic coast of South America. Through the Travel Cost Method we estimate the total touristic use value aggregated to Noronha Island by the travel cost was up to USD 312 million annually, of which USD 91.1 million are transferred to the local economy. Interviewing people from five different economic sectors, we show shark-diving contribute with USD 2.5 million per year to Noronha?s economy, representing 19% of the island?s GDP. Shark-diving provides USD 128.5 thousand of income to employed islanders, USD 72.6 thousand to government in taxes and USD 5.3 thousand to fishers due to the increase in fish consumption demanded by shark divers. We discover, though, that fishers who actually are still involved in shark fishing earn more by catching sharks than selling other fish for consumption by shark divers. We conclude, however, that the non-consumptive use of sharks is most likely to benefit large number of people by generating and money flow if compared to the shark fishing, providing economic arguments to promote the conservation of these species.