The Cape fur seal : monitoring and management in the Benguela Current ecosystem

Includes abstract.Includes bibliographical references.At the root of this thesis was the Benguela Current Large Marine Ecosystem (BCLME) Programme’s project "Top Predators as Biological Indicators of Ecosystem Change in the BCLME" (LMR/EAF/03/02). The objectives of this project were to assess the utility of top predators as biological indicators of ecosystem change in the Benguela Current Ecosystem, and implement an appropriate, integrated, system-wide monitoring programme based on top predators, to support ecosystem-based management in the Benguela Current Ecosystem

Assessing the hunting practices of Namibia's commercial seal hunt

Following mounting public concerns regarding the treatment of animals in recent years, there has been increasing interest in the development of science-based guidelines for animal welfare in industries such as agriculture and hunting.1,2,3 In the latter case, for example, the European Food Safety Authority (EFSA) was requested by the European Commission, in 2007, to issue a scientific opinion regarding welfare aspects of seal hunting and to assess the most appropriate killing methods, to reduce unnecessary suffering. As part of its assessment, EFSA's Scientific opinion4 compared seal hunting to the killing of livestock in abattoirs. It noted that while slaughter conditions vary considerably, the goal should be the same: to kill animals with the minimum amount of pain, distress and fear and without causing any avoidable suffering. The report concluded that there was strong evidence that effective killing is not always practiced during seal hunts and that unnecessary and avoidable pain and suffering occurs. Subsequently, Russia ended its commercial hunt for harp seals Pagophilus groenlandicus in the White Sea in February 20095 and banned the killing of all seals under the age of one year in March of 2009.6Two months later, the European Parliament voted 550-49 in favour of a resolution banning the importation of seal hunt products, which comes into effect in 2010.7 Canada and Norway have subsequently lodged challenges against the EU ban with the World Trade Organization

SURFACE PHYSICS MODELLING AND EVALUATION OF 6H-SILICON CARBIDE METAL-OXIDE-SEMICONDUCTOR FIELD EFFECT TRANSISTORS WITH EXPERIMENTAL CORROBORATION

The relatively recent commercial availability of silicon carbide (SiC) wafers has significantly increased the possibility of electronics based on SiC metal-oxide-semiconductor field effect transistor (MOSFET) design. However, current state-of-the-art SiC MOSFETs possess interface deformities that not only severally degrade SiC MOSFET performance but also complicate the modelling of the surface scattering mechanisms, rendering the conventional modelling techniques insufficient. At the time of this writing, little research towards developing tools that characterize the transport physics of experimentally observed SiC MOSFET behavior has been done. In this work I develop and implement a methodology capable of providing insight into the performance of this promising technology. In order to bridge the gap between theoretical physics and real world experimentation, I have developed a simulation tool capable of solving the drift-diffusion heat flow equations specialized for SiC MOSFETs. The simulator utilizes techniques such as finite difference approximation, linear iteration, and the Smart Newton method. With this simulator I am able to determine and predict details about the surface transport that are not readily accessible using conventional experimental techniques. Using the methodology presented above, I have succeeded in developing a tool that characterizes the physical transport mechanisms indigenous to current state-of-the-art SiC MOSFETs and achieves agreement with experimental data. In short, the gap between theory and experiment has been bridged, and its results provide valuable insight into the roles of various surface scattering mechanisms, including interface trap occupation, surface roughness, and temperature effects

The foraging ecology of female Cape fur seals (Arctocephalus pusillus pusillus) in South Africa

The marine environment is spatially and temporally dynamic and many marine ecosystems are experiencing impacts of broad-scale climate change. Within these ecosystems, marine predators play a crucial role in ecosystem function through their top-down influences on prey populations. These predators may also respond to bottom-up influences and changes at lower trophic levels. A thorough understanding of marine predator foraging ecology is thus important to improve our understanding of ecosystem function, inform conservation and management measures, and to predict the response of predators to future environmental change. The Cape fur seal (Arctocephalus pusillus pusillus) comprises a major proportion of the southern African marine predator biomass. However, little is known about the foraging distribution and behaviour of the species, despite its obvious importance within the ecosystem and increasing concerns regarding seal-fisheries conflict. Using a variety of technologies, including, GPS and satellite-linked tags, dive behaviour recorders, accelerometers and stable isotope analysis, this thesis investigated the foraging ecology of female Cape fur seals breeding on the coast of South Africa. First, to identify important foraging areas and assess the influence of geographic, temporal and environmental factors on these areas, lactating females from three breeding colonies were fitted with GPS or Argos-linked tracking devices, while individuals from two of these colonies were also fitted with dive behaviour recorders. Results revealed geographic differences in the foraging distributions and ranges of individuals between breeding colonies, which likely reflects a combined influence of ecological setting and density dependant competition. In addition, dive behaviour recorders revealed the occurrence of benthic foraging at both sites where they were deployed, and the dominance of this strategy in some individuals.Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 202

The foraging ecology of female Cape fur seals (Arctocephalus pusillus pusillus) in South Africa

The marine environment is spatially and temporally dynamic and many marine ecosystems are experiencing impacts of broad-scale climate change. Within these ecosystems, marine predators play a crucial role in ecosystem function through their top-down influences on prey populations. These predators may also respond to bottom-up influences and changes at lower trophic levels. A thorough understanding of marine predator foraging ecology is thus important to improve our understanding of ecosystem function, inform conservation and management measures, and to predict the response of predators to future environmental change. The Cape fur seal (Arctocephalus pusillus pusillus) comprises a major proportion of the southern African marine predator biomass. However, little is known about the foraging distribution and behaviour of the species, despite its obvious importance within the ecosystem and increasing concerns regarding seal-fisheries conflict. Using a variety of technologies, including, GPS and satellite-linked tags, dive behaviour recorders, accelerometers and stable isotope analysis, this thesis investigated the foraging ecology of female Cape fur seals breeding on the coast of South Africa. First, to identify important foraging areas and assess the influence of geographic, temporal and environmental factors on these areas, lactating females from three breeding colonies were fitted with GPS or Argos-linked tracking devices, while individuals from two of these colonies were also fitted with dive behaviour recorders. Results revealed geographic differences in the foraging distributions and ranges of individuals between breeding colonies, which likely reflects a combined influence of ecological setting and density dependant competition. In addition, dive behaviour recorders revealed the occurrence of benthic foraging at both sites where they were deployed, and the dominance of this strategy in some individuals.Thesis (PhD) -- Faculty of Science, School of Environmental Sciences, 202

Overlap in utilization of juvenile Cape Horse Mackerel by Cape Fur Seals and the purse-seine fishery in Namibia

The Cape horse mackerel Trachurus trachurus capensisis one of Namibia's most valuable fish stocks, and an important component to the diet of Cape fur seals, Arctocephalus pusillus pusillus, off northern Namibia. The level of overlap in the utilization of this resource between seals and the purse-seine fishery was investigated using two overlap indices. For high overlap measures, seals and the purse-seine fishery utilized age-2 horse mackerel. For low overlap measures, seals mainly consumed age-0 fish whereas the fishery caught age-2 fish. Both indices were adjusted by the proportion of horse mackerel in the seal diet, with the assumption that the proportion consumed by the seals reflects the abundance of horse mackerel in the coastal waters of Cape Cross, Namibia. Both unadjusted and adjusted overlap indices showed that overlap between seals and the fishery in their utilization of juvenile horse mackerel was high only at times when horse mackerel abundance was high, and low when abundance was small. Confidence intervals and significance testing were included. Overall, there was little overlap between seals and the purse-seine fishery. This study provides important information that should be taken into account in the management of the horse mackerel resource

First African Marine Mammal Colloquium, South Africa, May 2010

The African Marine Mammal Colloquium (AMMC) was initiated to provide a platform for increased collaboration and communication between researchers working on marine mammals in and around Africa. The first meeting of the AMMC was held at Kleinbaai, South Africa, in May 2010. Talks were presented by each of the 48 participants and a number of discussion groups were held. Several countries were represented but most presentations and discussions were centred on research within the host country. In all, 13 papers that were based on presentations at the AMMC were selected after peer-review to appear in a special issue of the African Journal of Marine Science. Its theme, ‘Conservation biology of marine mammals in the southern African subregion’, reflects both the geographical area represented in these papers and their common subject.http://www.tandfonline.com/loi/tams2

Effects of Flooding on the Longleaf Pine-Wiregrass Ecosystem

Proceedings of the 1995 Georgia Water Resources Conference, April 11 and 12, 1995, Athens, Georgia.Flood waters associated with Tropical Storm Alberto inundated 21 km2 of uplands at Ichauway, a 115 km 2 ecological reserve located in southwestern Georgia. At the landscape scale, sink holes were formed, landslides and erosion occurred along riverine bluffs and terraces, and sediment deposition occurred along all riparian corridors. Xeric habitats, dominated by longleaf pine-wiregrass and scrub-shrub, were disproportionately affected by flooding on an area basis. Longleaf pine seedlings and saplings with apical meristems above high water always survived. Mortality of submerged longleaf pine and wiregrass was positively related to flooding depth and duration. Treefall in bluff riparian zones and hardwood hammocks reflected species composition within the two habitats although oaks and southern red cedar were the most commonly downed trees in both habitats. Higher treefall was observed in bluff riparian zones and may be related to constrained stream channel geomorphology. Although infrequent, flooding appears to be important in governing the structure and function of the longleaf pine-wiregrass ecosystem and, along with other disturbances, should be explicitly incorporated into reserve and riparian corridor planning and design.Sponsored and Organized by: U.S. Geological Survey, Georgia Department of Natural Resources, The University of Georgia, Georgia State University, Georgia Institute of TechnologyThis book was published by the Carl Vinson Institute of Government, The University of Georgia, Athens, Georgia 30602 with partial funding provided by the U.S. Department of Interior, Geological Survey, through the Georgia Water Research Institute as authorized by the Water Resources Research Act of 1990 (P.L. 101-397). The views and statements advanced in this publication are solely those of the authors and do not represent official views or policies of the University of Georgia or the U.S. Geological Survey or the conference sponsors

Accuracy of ARGOS Locations of Pinnipeds at-Sea Estimated Using Fastloc GPS

Background: ARGOS satellite telemetry is one of the most widely used methods to track the movements of free-ranging marine and terrestrial animals and is fundamental to studies of foraging ecology, migratory behavior and habitat-use. ARGOS location estimates do not include complete error estimations, and for many marine organisms, the most commonly acquired locations (Location Class 0, A, B, or Z) are provided with no declared error estimate.Methodology/Principal Findings: We compared the accuracy of ARGOS locations to those obtained using Fastloc GPS from the same electronic tags on five species of pinnipeds: 9 California sea lions (Zalophus californianus), 4 Galapagos sea lions (Zalophus wollebaeki), 6 Cape fur seals (Arctocephalus pusillus pusillus), 3 Australian fur seals (A. p. doriferus) and 5 northern elephant seals (Mirounga angustirostris). These species encompass a range of marine habitats (highly pelagic vs coastal), diving behaviors (mean dive durations 2&ndash;21 min) and range of latitudes (equator to temperate). A total of 7,318 ARGOS positions and 27,046 GPS positions were collected. Of these, 1,105 ARGOS positions were obtained within five minutes of a GPS position and were used for comparison. The 68th percentile ARGOS location errors as measured in this study were LC-30.49 km, LC-2 1.01 km, LC-1 1.20 km, LC-0 4.18 km, LC-A 6.19 km, LC-B 10.28 km. Conclusions/Significance: The ARGOS errors measured here are greater than those provided by ARGOS, but within the range of other studies. The error was non-normally distributed with each LC highly right-skewed. Locations of species that make short duration dives and spend extended periods on the surface (sea lions and fur seals) had less error than species like elephant seals that spend more time underwater and have shorter surface intervals. Supplemental data (S1) are provided allowing the creation of density distributions that can be used in a variety of filtering algorithms to improve the quality of ARGOS tracking data.<br /