Global ETD Search

1	Management of the Seychelles artisanal fishery Wakeford, Robert Charles January 2001 (has links) No description available. 577
2	A distribuição espacial e a composição das capturas de elasmobrânquios pela frota de emalhe de Passo de Torres - SC na costa sul do Brasil, no verão de 2004/2005 Galina, André Beal January 2006 (has links) Dissertação(mestrado) - Universidade Federal do Rio Grande, Programa de Pós–Graduação em Oceanografia Biológica, Instituto de Oceanografia, 2006 / Submitted by Cristiane Gomides (cristiane_gomides@hotmail.com) on 2013-11-18T15:49:45Z No. of bitstreams: 1 Beal.pdf: 944473 bytes, checksum: b8b64f4df525f2ad19ff1c3207ace0e6 (MD5) / Approved for entry into archive by Angelica Miranda (angelicacdm@gmail.com) on 2013-11-18T19:23:31Z (GMT) No. of bitstreams: 1 Beal.pdf: 944473 bytes, checksum: b8b64f4df525f2ad19ff1c3207ace0e6 (MD5) / Made available in DSpace on 2013-11-18T19:23:31Z (GMT). No. of bitstreams: 1 Beal.pdf: 944473 bytes, checksum: b8b64f4df525f2ad19ff1c3207ace0e6 (MD5) Previous issue date: 2006 / Os elasmobrânquios são explorados por várias artes de pesca no Rio Grande do Sul. Com o intuito de caracterizar a frota pesqueira de emalhe sediada na fronteira sul do Estado de Santa Catarina, descrever as capturas e a distribuição espacial das espécies de elasmobrânquios na plataforma continental do Rio Grande do Sul, bem como descrever a estrutura populacional de Carcharhinus sp., foram realizadas 34 amostragens de desembarques pela frota pesqueira de Passo de Torres (SC), e nove embarques em viagens de pesca dessa frota, entre novembro de 2004 e março de 2005. O tamanho da frota foi de 30 embarcações, com comprimento total variando entre 10 e 20 m. Neste período, foram utilizadas redes de emalhe de superfície (cação e enchova) e de fundo (corvina, viola e papa-terra). Quinze espécies de tubarões e 12 de raias foram registradas. Entre os elasmobrânquios, Sphyrna lewini teve o maior peso total desembarcado, seguida de Rhinobatos horkelii. Dentre os peixes ósseos, Micropogonias furnieri apresentou os maiores valores de peso total desembarcado. As redes de emalhe de fundo, em especial a de corvina, foram as que mais capturaram exemplares de Carcharhinus sp., que utilizam a área como berçário durante o verão. Os principais problemas para a conservação dos tubarões na região, são a sobrepesca e a captura acidental, que atinge elevado número de neonatos. Sugere-se para a preservação dos tubarões no sul do Brasil, a proibição das redes dirigidas aos elasmobrânquios e a exclusão da pesca nas áreas de hábitat críticas para os neonatos, jovens e adultos. / The elasmobranch fishes are exploited by many fisheries gears in Rio Grande do Sul state. The purposes of this study were to describe the inshore fishery of Passo de Torres (SC), south frontier with Rio Grande do Sul state, to assess the elasmobranchs catches and its composition, and to deliniate their spatial distribution in south continental shelf. Thirty-four landings and nine fishing trips as observer in commercial fishing vessel were monitored, between November 2004 and March 2005. The fleet was compounded by 30 fishing vessels, with size between 10-20 m, and utilized surface and bottom gillnets to capture teleosts and elasmobranch fishes. Fifteen shark and 12 ray species were recorded in this study. Sphyrna lewini had the highest landing in total weight, followed by Rhinobatos horkelii. Among teleosts, Micropogonias furnieri had the highest landing in total weight. The bottom gillnets, specially the one directed for M. furnieri, had the highest capture of Carcharhinus sp., which utilize the area as nursery grounds during the summer. Others elasmobranchs were also by-catch from gillnets. In the study area, the main problems to shark conservation are heavy fishing pressure and by-catch, that capture high numbers of newborn. To shark management in south Brazil, we suggest the exclusion of fisheries with directed gears for elasmobranchs, and the creation of fisheries reserves in these critical habitats for newborn, young and adults. Pesca costeira Emalhe Elasmobrânquios Carcharhinus sp. Berçários Inshore fisheries Gillnet Elasmobranchs Nursery
3	The Nearshore Hardbottom Fishes of Broward County, Florida USA Baron, Robert M. 01 July 2002 (has links) Some shallow (<7m, water depth) nearshore hardbottom areas of Southeast Florida have been reported to function as important juvenile habitat. I characterized the nearshore fish communities along a 30km stretch of coastline of Broward County, Florida from visual census data. Two-hundred transect-counts, 100 point-counts and 98 rover-diver counts were completed by myself and others during June-August, 2001. The abundance of all fish species and their sizes were recorded. The transects (30m long, 2m wide, 1m high) were laid perpendicular (compass heading 90°) to the innermost edge of hardbottom. Transects were placed every 152m of coastline. Altemately, a point-count or 20 min rover-diver count was also performed over the hard bottom just north of the 30m transect. All counts occurred between approximately 2m and 6m water depth. One hundred-sixty nine species and over 72,000 fish were recorded. Recently settled juveniles (≤ 5cm) were the dominant component (>80%) of the inshore fish community, consisting primarily (>90%) of grunts (Haemulidae). Visual Census Inshore Reef Juvenile fish habitat Marine Biology
4	The distribution, movements and abundance of Heaviside's dolphins in the nearshore waters of the Western Cape, South Africa Elwen, Simon Harvey 06 January 2009 (has links) Heaviside's dolphin (Cephalorhynchus heavisidii) is a poorly studied coastal delphinid with a limited inshore distribution off the west coast of southern Africa where it is sympatric with the similar sized dusky dolphin (Lagenorhynchus obscurus). It is exposed to an unknown level of bycatch particularly in near-shore set-net fisheries and is also potentially impacted by the growing boat-based whale watching industry in South Africa. In this thesis I describe the results of a study investigating the distribution, movements, behaviour and abundance of Heaviside's dolphins in the near-shore environment of the Western Cape of South Africa as a precursor to assessing its potential vulnerability to anthropogenic threats. Data were gathered using three different approaches in the field; diurnal shore based observations, boat based photo-ID surveys along ~390 km of coastline and satellite telemetry. Data were collected for dusky dolphins where feasible. Heaviside’s dolphins exhibited a strong pattern of resting inshore during daytime and foraging offshore at night that was presumed to be related to the movement of juvenile hake (Merluccius capensis) closer to the surface at night. In addition, despite near-shore observations failing to indicate feeding, dolphins were consistently found to be more abundant along regions of the coast which over the long term had higher levels of small hake available offshore. In contrast the near-shore distribution of dusky dolphins varied considerably between years possibly due to the very near-shore environment being at the edge of their habitat. A tendency for dusky dolphins to move offshore during upwelling conditions was observed from shore in St Helena Bay, the site of a strong predictable upwelling cell. However this was the only location in which very large groups of animals (50-500) were seen during coastal boat surveys suggesting this pattern may have been area specific and feeding strategies may vary throughout their range. Sympatric appears to be mediated by differences in overall range and prey type and size differentiation. Heaviside’s dolphins were found to have small home ranges and show a high degree of site fidelity over several years, at least during summer months. Dolphins fitted with satellitelinked transmitters used only limited home ranges (~876 to 1990 km2) which scaled positively with body size within the ~50 day tracking period, while photographically identified animals did not disperse significantly further than this over 3 years. The maximum coastwise displacement observed for an individual (88.4 km after 1 year) was considerably less than the 390 km length of the overall study area, and equivalent to the maximum coastwise movement seen during satellite-tagging (83.1 km). This suggests that measured home ranges may be stable over several years, although the number of resighted individuals (n = 76) was small and (as data collection was restricted to summer months) seasonal differences in movements or migrations cannot be ruled out. Associations among photographically identified animals did not differ from a random mixing of individuals, suggesting that this species has a fission-fusion type social structure at least over the short term. The abundance of Heaviside's dolphins was calculated from photo-ID mark-recapture data at three spatial scales using Chapman’s modified Petersen estimators. The proportion ofdistinctively marked individuals in this species is low (14 - 17%) reducing sample sizes and introducing a large extrapolation factor, both of which contribute to an increase in the variance of any resultant population estimate. Using resightings after one year, the total number of animals over the whole 390km study area was calculated to be 6345 (CV = 0.26, CI = 3573 – 11 267) while using same-season re-sightings the total number of animals using a 20km long section of coastline in the centre of the study area was calculated as 527 (CV = 0.35, CI = 272 – 1020). These estimates may be significantly biased downwards by the effects of heterogeneity in the capture probability of individuals which it was not possible to account for analytically due to small sample sizes. Sympatry of Heaviside's and dusky dolphins appears to be mediated by differences in the overall range and in the type and size of prey consumed. From a conservation point of view, our findings for Heaviside's dolphins are encouraging in that they indicate a relatively large population size, although their strong site fidelity does make them more vulnerable to localised impacts than a more widely ranging species like dusky dolphins and this needs to be considered during management of the population. / Thesis (PhD)--University of Pretoria, 2009. / Zoology and Entomology / unrestricted Western Cape Province, South Africa Offshore Inshore Dusky dolphins UCTD
5	Modelo paramétrico regional da corrente do Brasil na Bacia de Campos / Regional parametric model of the Brazil Current in the Campos Basin Costa, Thiago Podadera 09 February 2012 (has links) Um modelo paramétrico regional tridimensional da Corrente do Brasil (CB) foi construído com o objetivo de investigar se o meandramento frontal da CB domina a variabilidade subinercial na Bacia de Campos. A parametrização da CB normal à costa seguiu a formulação proposta por Schmidt et al. [2007]. Os parâmetros da CB foram estimados a partir dos perfis de velocidade quase-sinóticos durante a amostragem do cruzeiro OCEANO SUDESTE II (OCSEII) da Marinha do Brasil. A frente térmica costeira (FTC), facilmente detectado na superfície do mar por imagens de satélite, é tida como a fronteira costeira do CB com velocidades desprezíveis. A FTC padrão é, então, inferida pelo método do gradiente máximo em uma data escolhida. Com a localização da FTC, várias radiais são projetadas normalmente à frente e os perfis de velocidades da CB são ajustados a estas radiais. O próximo passo é interpolar objetivamente o campo de velocidade para obter uma CB tridimensional. A variabilidade espacial da CB neste mapa é, portanto, unicamente devido à arqueamento da velocidade/ FTC, e os padrões de velocidade são devidos apenas ao meandramento frontal. Estes foram identificados nas séries temporais das FTC e o modelo foi computado para dois eventos separados no inverno de 2007 e comparados com os dados de ADCPs da PETROBRAS montados em quatro plataformas de petróleo. A comparação foi feita usando compósitos semanais e médias para isolar movimentos de mesoescala. Isso mostra que há um acordo muito favorável entre o modelo e as medições de velocidade de mar aberto em ambas as magnitudes e direções. Este assegura que os meandros frontais, ou mais especificamente, o meandro de São Tomé domina a variabilidade subinercial ao longo do talude continental e do platô de São Paulo. A única exceção é para o ADCP montado sobre uma plataforma de petróleo em plataforma continental. O modelado e as observações in situ discordam e indicam que outros fenômenos, tais como ondas de plataforma, devem ser contabilizados na parte costeira / A regional three-dimensional parametric model of the Brazil Current (BC) was built with the goal of investigating whether or not the BC frontal meandering dominates the subinercial current variability in the Campos Basin. The BC cross-stream parametrization followed the formulation proposed by Schmidt et al. [2007]. The BC parameters were estimated from quasi-synoptic velocity profiling sampled during the Brazilian Navy cruise OCEANO SUDESTE II (OCSEII). The surface inshore thermal front (ITF),easily detected in sea surface temperature satellite images, is taken as the inshore border of the BC jet with negligible velocities. The ITF spatial pattern is then inferred by the maximum gradient method on a chosen date or period. With the ITF location, several BC cross-strem profiles are projected normally to it. The next step is to objectively interpolate the velocity field to obtain a three-dimensional BC. The spatial variability of the BC in this map is therefore solely due to the arching of the velocity/ITF front, and therefore, the velocity patterns are due to frontal meandering only. Meandering events were identified in the IFT time series, the model computed the BC frontal patterns for two separate events in the winter of 2007 and compared with PETROBRAS\' ADCP records mounted on four oil rigs. The comparison was done using weekly composites and averages to isolate mesoscale motions. It shows that there is a very favorable agreement between between the model and the open sea velocity measurements in both magnitude and direction. This reassures that the frontal meandering, or more specifically, the S~ao Tom´e Meander formation dominates the subinertial variability over the continental slope and the S~ao Paulo Plateau. The only exception is for the ADCP mounted on an oil rig on the continental shelf. The modeled and in situ observations disagree and indicate that other phenomena, such as shelf waves, should be accounted in the coastal ocean in addition to the BC meandering. Brazil current Corrente do Brasil Frente Térmica Costeira frontal meandering inshore thermal front meandramento frontal Modelo Paramétrico parametric model
6	Modelo paramétrico regional da corrente do Brasil na Bacia de Campos / Regional parametric model of the Brazil Current in the Campos Basin Thiago Podadera Costa 09 February 2012 (has links) Um modelo paramétrico regional tridimensional da Corrente do Brasil (CB) foi construído com o objetivo de investigar se o meandramento frontal da CB domina a variabilidade subinercial na Bacia de Campos. A parametrização da CB normal à costa seguiu a formulação proposta por Schmidt et al. [2007]. Os parâmetros da CB foram estimados a partir dos perfis de velocidade quase-sinóticos durante a amostragem do cruzeiro OCEANO SUDESTE II (OCSEII) da Marinha do Brasil. A frente térmica costeira (FTC), facilmente detectado na superfície do mar por imagens de satélite, é tida como a fronteira costeira do CB com velocidades desprezíveis. A FTC padrão é, então, inferida pelo método do gradiente máximo em uma data escolhida. Com a localização da FTC, várias radiais são projetadas normalmente à frente e os perfis de velocidades da CB são ajustados a estas radiais. O próximo passo é interpolar objetivamente o campo de velocidade para obter uma CB tridimensional. A variabilidade espacial da CB neste mapa é, portanto, unicamente devido à arqueamento da velocidade/ FTC, e os padrões de velocidade são devidos apenas ao meandramento frontal. Estes foram identificados nas séries temporais das FTC e o modelo foi computado para dois eventos separados no inverno de 2007 e comparados com os dados de ADCPs da PETROBRAS montados em quatro plataformas de petróleo. A comparação foi feita usando compósitos semanais e médias para isolar movimentos de mesoescala. Isso mostra que há um acordo muito favorável entre o modelo e as medições de velocidade de mar aberto em ambas as magnitudes e direções. Este assegura que os meandros frontais, ou mais especificamente, o meandro de São Tomé domina a variabilidade subinercial ao longo do talude continental e do platô de São Paulo. A única exceção é para o ADCP montado sobre uma plataforma de petróleo em plataforma continental. O modelado e as observações in situ discordam e indicam que outros fenômenos, tais como ondas de plataforma, devem ser contabilizados na parte costeira / A regional three-dimensional parametric model of the Brazil Current (BC) was built with the goal of investigating whether or not the BC frontal meandering dominates the subinercial current variability in the Campos Basin. The BC cross-stream parametrization followed the formulation proposed by Schmidt et al. [2007]. The BC parameters were estimated from quasi-synoptic velocity profiling sampled during the Brazilian Navy cruise OCEANO SUDESTE II (OCSEII). The surface inshore thermal front (ITF),easily detected in sea surface temperature satellite images, is taken as the inshore border of the BC jet with negligible velocities. The ITF spatial pattern is then inferred by the maximum gradient method on a chosen date or period. With the ITF location, several BC cross-strem profiles are projected normally to it. The next step is to objectively interpolate the velocity field to obtain a three-dimensional BC. The spatial variability of the BC in this map is therefore solely due to the arching of the velocity/ITF front, and therefore, the velocity patterns are due to frontal meandering only. Meandering events were identified in the IFT time series, the model computed the BC frontal patterns for two separate events in the winter of 2007 and compared with PETROBRAS\' ADCP records mounted on four oil rigs. The comparison was done using weekly composites and averages to isolate mesoscale motions. It shows that there is a very favorable agreement between between the model and the open sea velocity measurements in both magnitude and direction. This reassures that the frontal meandering, or more specifically, the S~ao Tom´e Meander formation dominates the subinertial variability over the continental slope and the S~ao Paulo Plateau. The only exception is for the ADCP mounted on an oil rig on the continental shelf. The modeled and in situ observations disagree and indicate that other phenomena, such as shelf waves, should be accounted in the coastal ocean in addition to the BC meandering. Corrente do Brasil Frente Térmica Costeira meandramento frontal Modelo Paramétrico Brazil current frontal meandering inshore thermal front parametric model
7	Modelling risk of chronic oil pollution from vessel operations in Canada's West Coast Serra-Sogas, Norma Sara 06 August 2010 (has links) Chronic oil pollution or frequent small-scale oil discharges from vessel operations is an important source of marine oil pollution and considered a constant threat to marine and coastal environments. In Canada’s Pacific region, evidence of such illegal discharges has been gathered by the National Aerial Surveillance Program (NASP) from 1998 to 2007. We used this information to fit Generalized Linear Models (GLMs) for offshore waters and inshore waters and explore the relationships between oil spill occurrences and four predictor variables: shipping traffic densities for different vessel types, distance to shore, distance to port and density of small harbours. The best-fit models for both regions show that areas closer to shore and with higher density of small harbours have a higher probability of oil spill occurrences. However, only in inshore waters was shipping traffic significantly related with oil spill occurrences. Tug boats and oil tanker traffic show a significant positive relationship with oil spill observations, while carriers presented a negative association. Mapped results for offshore areas depicted the highest probability of oily discharges in Barkley Sound and at the entrance of the Juan de Fuca Strait; whereas in inshore waters, oil pollution hot spots were found in the vicinity of major commercial and tourist centres. These probability maps were used to identify Coastal and Marine Protected Areas (CMPAs) and Important Bird Areas (IBAs) more likely to be exposed to chronic oil pollution during a period of 10 years. Three areas were highlighted as the most vulnerable based on their likelihood of exposure and the sensitivity of the species they contain to oil pollution. These sites are the Tofino Mudflats, Barkley Sound, Scott Islands and the Sturgeon and Robert Banks, in the Fraser River delta. Our findings provide better understanding of the relationships between oil spill occurrences and vessel operations and help us identify likely oil pollution hot spots and sites particularly vulnerable to this stressor in Canada’s Pacific region. This information can be useful to NASP in improving its efficiency and in targeting monitoring efforts to troublesome areas. Additionally, this research contributes to regional studies that focus on analyzing the distribution of anthropogenic stressors from sea-based activities in British Columbia. Finally, we highlight the importance of collecting accurate data to properly model the probability of oil spill occurrences and encourage future research aiming to better understand and ultimately reduce the chronic release of pollutants from shipping activities into the marine environment. marine oil pollution modelling Canada risk inshore waters offshore waters
8	Postglazialer Anstieg des Meeresspiegels, Paläoklima und Hydrographie, aufgezeichnet in Sedimenten der Bermuda inshore waters / Postglacial rise of sea level, palaeoclimate and hydrography, recorded in sediments of the Bermuda inshore waters Vollbrecht, Rüdiger Dr. 13 January 1997 (has links) No description available. 550 Geowissenschaften Mathematics and Computer Science Postglazial Meeresspiegel Paläoklima Hydrography Bermuda Sedimente Pleistozän Holozän Quartär Seen Küste Laminite Solarzyklen Sonnenzyklen marin lakustrin Geologie Karbonate Böden Karst Torf Isotopen-Geochemie Altersbestimmung Fazies Paläökologie postglacial sea level palaeoclimate paleoclimate hydrography Bermuda sediments Pleistocene Holocene Quaternary inshore waters lakes laminites solar cycles lacustrine marine geology carbonates soil karst peat isotope geochemistry radiocarbon dating facies palaeoecology paleoecology 38.48 Marine Geologie 38.41 Sedimentation 38.82 Klimatologie 38.19 Historische Geologie: Sonstiges 38.32 Geochemie 38.88 Regionale Hydrologie 38.47 Moore 38.90 Ozeanologie Ozeanographie VAT 250 Litorale Sedimente VCA 520 Quartärgeologie VDI 210 Pleistozän VDI 220 Holozän VEW 200 Karibischer Raum VEZ 130 Inselgruppen TWC 600 Paläoklimatologie VKB 380 Sedimente bestimmter Regionen VKB 378 Rhytmite VKB 376 Organogene Sedimentgesteine VKB 340 Fazieskunde VKB 333 Sonstige Sedimentationsprozesse VKB 332 Sedimentationsbedingungen UHA 700 Marine Geologie (Küsten Watt Inselbildung etc.) UHA 440 Schwankungen

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