https://commons.ru.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://commons.ru.ac.za/vital/access/manager/Repository/vital:4639 Wed 12 Oct 2022 12:31:41 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5746 0.05). At a constant temperature (20°C), the oxygen consumption rate of M. wooldridgei decreased with an increase in salinity. Salinity tolerance of the mysid was strongly modified by temperature. At 5‰ and 30°C, mysids exhibited mass mortality. The Q10 value for M. wooldridgei at 15, 25 and 35‰ was estimated at 2.34, 1.44 and 2.14, respectively. Results of the study suggest that M. wooldridgei is well adapted to surviving in environments characterised by variations in temperature and salinity. Within the Great Fish Estuary, total chl. a concentration ranged between 2.68 μg L-1 and 31.12 μg L-1 and was always dominated by large phytoplankton cells (>5 μm). Average zooplankton abundance ranged between 62 and 28 917 ind. m-3 and biomass between 10 and 203 mg Dwt m-3. The zooplankton community was numerically dominated by the calanoid copepod Pseudodiaptomus hessei, which comprised up to 100% (range between 12 and 100%) of the total zooplankton counted. Total zooplankton biomass during the day was dominated by copepods and by mysids during the nighttime. Among the mysids, M. wooldridgei was the most numerically abundant mysid and comprised <10% of the total zooplankton abundance. Numerical analysis found no seasonal pattern in the total zooplankton abundance (including mysids). The lack of any seasonality could be attributed to the continuous freshwater inflow into the estuary due to the inter-basin transfer of water from the Gariep Dam to the Fish River system. A distinct spatial pattern in the zooplankton community structure was evident with the upper stations almost entirely dominated by the copepod P. hessei, while at stations occupied in the lower reaches of the estuary, the zooplankton community comprised a mixture of freshwater, estuarine and marine breeding zooplankton species. The mysids also demonstrated a distinct spatial pattern in their distribution. Mysids were generally absent from the upper reaches, while in the middle reaches Rhopalophthalmus terranatalis and M. wooldridgei were numerically dominant. Gastrosaccus brevifissura dominated in the lower regions of the estuary. Stable isotope analysis (δ13C) indicated that the dominant source of carbon utilised by the numerically dominant copepods and juvenile M. wooldridgei within the estuary was derived from the extensive phytoplankton stocks within the system. In contrast, sub-adult and adult mysids (R. terranatalis, M. wooldridgei and G. brevifissura) appeared to consume a combination of phytoplankton and copepods. The contribution of the various sources of carbon to the total carbon intake of the mysid remains unknown.]]> Wed 12 May 2021 23:42:36 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4192 Wed 12 May 2021 23:18:25 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4687 Wed 12 May 2021 23:14:39 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3168 Wed 12 May 2021 23:04:23 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3990 Wed 12 May 2021 22:59:27 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5511 Wed 12 May 2021 22:45:13 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5684 Wed 12 May 2021 22:44:38 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3833 Wed 12 May 2021 22:38:20 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4412 Wed 12 May 2021 22:37:27 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5704 7mm) were equivalent to ≈10% and ≈5% of body dry weight, respectively. The von Bertalanffy growth curve parameters were empirically identified, by cohort analysis of data collected during 4 years, as K = 0.22239/year, L[subscript]∞ = 14.05789mm, t₀ = -0.05174, L₀ = 0.16083mm. N. marionis can survive up to seven years under natural conditions.]]> Wed 12 May 2021 22:28:01 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4742 Wed 12 May 2021 20:27:36 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5698 Wed 12 May 2021 19:49:58 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5223 Wed 12 May 2021 19:29:46 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3956 Wed 12 May 2021 19:06:36 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3941 Wed 12 May 2021 18:57:34 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5938 120kg), adult (41%) and male (39%) and the five most commonly killed species (kudu, black wildebeest, warthog, bushbuck and Blesbuck) comprised 67.9% of all kills and 67.8% of total biomass consumed. In an attempt to overcome the problem of gaps in the kill lists, a subset of data, which excluded kills more than five days apart, was analyzed and this gave similar results to analysis of the full kill lists. Mean daily intake rates varied annually between 2.26 and 5.23kg.FEQ⁻¹ for the full data set and 4.53 and 1 0.46kg.FEQ⁻¹ for the subset. The difference between estimated (calculated using daily intake rates of 5 and 7.12kg.FEQ⁻¹) and observed offtake for each ungulate species reflected the preference ratings for that species. Analysis of bone marrow indicated that: lions killed ungulates in moderate to good condition; condition of culled animals was lower than that of kills; distal bones could be used in analyses; and that that bones exposed to the environment for at least a week could be used to analyze condition of prey. Home ranges and activity centers ranged from 21.42km² to 73.27km² and 2.7lkm² to 17.47km² respectively, which was smaller than expected from previous studies. Although, lions at K wandwe and Shan1wari preferred different vegetation types, at both reserves they generally occupied areas that were structurally similar to what has previously been reported. Continuous monitoring and analyses of diet, including condition of the prey, and habitat use will provide reserve managers with some of the necessary information to enable them to effectively manage their lion populations and to predict and minimize potential problems.]]> Wed 12 May 2021 18:47:34 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4074 Wed 12 May 2021 18:22:11 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5742 0.05 in all other cases). There were two distinct spatial patterns in the distribution of the larger ichthyofauna (>50mm SL). These corresponded to a grouping associated with the mouth region and a grouping associated with the remaining regions of the estuary. Stable isotope analysis indicated that the primary source of carbon utilised by the ichthyofauna of the Kasouga estuary was derived from the channel, most likely microphytobenthic algae. The contributions of the riparian and salt marsh vegetation to the total carbon flow appear to be minimal.]]> Wed 12 May 2021 18:18:06 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3797 Wed 12 May 2021 17:14:56 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4603 Wed 12 May 2021 16:51:19 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3954 Wed 12 May 2021 16:30:02 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3948 Wed 12 May 2021 16:14:46 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3946 Wed 12 May 2021 16:14:37 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5315 0.05; n=150). Pigmented puerulus (p<0.05; n=566) and juveniles (p<0.05; n=3528) preferred structurally complex structures that provided better shelter such as crates, which were more sheltered from sea swells, compared to oyster bags. Among oyster rafts, pigmented puerulus and juveniles preferred occupying the sheltered and centred raft areas, which provided better protection from wave action, compared to exposed raft areas, which were exposed to the incoming swell. Puerulus and juvenile lobster appeared to recolonise adjacent bags and crates, and possibly migrate to the substrate and off the farm due to the disturbance of the habitat during harvesting. The booth crevice collector was more efficient in collecting puerulus possibly due to the high structurally complex habitat and the better shelter they provided compared to the hogshair collector. The occupation of structurally complex habitats by early benthic stages may be related to morphological changes associated with metamorphosis. Puerulus settlement peaked during early spring (August-September) and was related to low sea surface temperatures (12.3°C), strong south winds, and moderate swells in the week preceding settlement. These conditions are synonymous with the “spring upwelling” season of the Lüderitz upwelling cell in the central Benguela current region. Puerulus nutritional condition peaked during this period possibly due to high levels of planktonic food (due to high nutrients from upwelling) that was available to the late stage phyllosoma larvae further offshore. A “good” puerulus settlement year during 2000 was associated with lower than average SST (11.6°C) and strong south winds and was followed by “poor” puerulus settlement years during 2001 and 2002 when higher than average SST were experienced with below average wind speeds experienced during 2001 only. Puerulus of J. lalandii recruited in high numbers into Lüderitz Bay during the new moon, full moon and last quarter moon phases by making use of the increased tides during these phases of the lunar cycle. Peak juvenile abundance during early summer (November-December) lagged by 8 weeks was significantly correlated with peak puerulus abundance. Puerulus size was similar (8.5–9.7mm CL) over the study period. Juvenile cohorts, 9.9-20.6mm CL in size recruited in 2 distinct waves in August 2001-June 2002 and July 2002-February 2003. The 2001/2002 recruits had higher monthly growth increments and better nutritional condition compared to 2002/2003 recruits. Peak frequencies of 2nd moult juveniles (9.9- 10.8mm CL) occurred in September of both recruitment events with nutritional condition being poorest during the 2002/2003 event. The nutritional condition of the settling puerulus did not appear to be related to the subsequent growth of juvenile lobster. These preliminary results suggest that pueruli recruit once a year mainly during late winter/ early spring under conditions typical of coastal upwelling in the Benguela current near Lüderitz. It appears that puerulus settlement is driven by favourable shoreward currents, which help in transporting puerulus to their settlement grounds. Puerulus supply is highly variable between years, which appears to be consistent with a highly variable Benguela environment. The oyster farm supported a substantial standing stock averaging 123 800 lobster per day (range: 22 600-325 300 lobster per day) of which 26 600 were puerulus and 97 200 were juveniles, that may have been harvested once off on any given day during the sample period. Monthly harvesting of the total lobster standing stock during the one and a half year sampling period was just over 2 million lobsters (505 700 pueruli and 1.85 million juveniles) and would potentially have been sufficient seed for a 200 ton lobster production in puerulus lobster growout facilities. In the light of high inter-annual variation in puerulus settlement observed at Lüderitz, the seed supply at the Lüderitz oyster farm is clearly limited and therefore it is prudent that other sites of high puerulus settlement is established before large commercial scale lobster growout can commence. The migration of lobster off the farm suggested that these lobsters potentially recruit to the fishery and therefore harvesting the entire standing stock on the farm may have adverse negative effects on the wild fishery. A policy decision will be required as to whether more efficient harvesting of lobster from the farm should be allowed. If puerulus removal in J. lalandii for aquaculture is allowed in the near future, it should be conducted on an experimental scale or small commercial scale until the potential effects on recruitment into the fishery are clearer.]]> Wed 12 May 2021 16:07:37 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3953 Wed 12 May 2021 15:53:29 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4256 Wed 12 May 2021 15:46:14 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5232 Thu 13 May 2021 10:47:23 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4631 Thu 13 May 2021 08:16:07 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:6032 Thu 13 May 2021 08:11:28 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3986 Thu 13 May 2021 08:03:28 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5832 Thu 13 May 2021 07:35:55 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5328 Thu 13 May 2021 07:25:33 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3839 Thu 13 May 2021 06:47:49 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5112 1800mm). The musculoskeletal responses indicated that Tall subjects were forced to adopt the most awkward general body postures as a result of the low computer screen. However, the low screen allowed for the Short subjects to adopt the most natural general body postures, although levels of muscular activity in the upper trapezius suggest that the muscular load imposed on both Short and Tall subjects was significantly greater than that imposed on the Medium subjects. In addition, the Medium subjects’ perceptions of the Standard workstation dimensions support the fact that this workstation was better suited to users with “average” morphologies. The responses elicited in the Personalised and Wrist Support workstations were improved significantly when compared to the Standard workstation. Joint angles were more natural, upper trapezius EMG was reduced, standard of performance improved and perceptual responses indicated a diminished incidence of body and visual discomfort, as well as greater perceived satisfaction with these workstation dimensions. The improved physical responses suggest a decrease in the risk of developing cumulative trauma disorders. Although subjects were unaccustomed to the wrist support device, this workstation demonstrated a further reduction in the range of wrist angles, as well as a general positive attitude towards the concept.]]> Thu 13 May 2021 05:56:42 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4068 Thu 13 May 2021 04:58:30 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3869 Thu 13 May 2021 04:37:15 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5913 0.05). The multivariate analysis identified two interacting mechanisms controlling the distribution patterns, abundance and biomass of the various euphausiid species, namely (1) diel changes in abundance and biomass, (2) and restricted distribution patterns associated with the different water masses. Ingestion rates were determined for five euphausiid species. E. triacantha was found to have the highest daily ingestion rate ranging from 1 226.1 to 6 029.1 ng pigm ind⁻¹d⁻¹, while the lowest daily ingestion rates were observed in the juvenile Thysanoessa species (6.4 to 943.0 ng pigm ind⁻¹ d⁻¹). The total grazing impact of the selected euphausiids ranged from < 0.1 to 20.1 μg pigm m⁻²d⁻¹, corresponding to < 0.15 % of the areal chl-a biomass. The daily ration estimates of autotrophic carbon for the euphausiids suggested that phytoplankton represented a minor component in their diets, with only the sub-adult E. vallentini consuming sufficient phytoplankton to meet their daily carbon requirements. A cyclonic cold-core eddy spawned from the region of the APF located in the southwest Indian sector of the PFZ was the dominant feature during the 2005 survey. The total areal chl-a biomass throughout the region was low, ranging between 5.6 and 11.4 mg chl-a m⁻², and was significantly higher within the core of the eddy compared to the surrounding waters (p < 0.05). RMT-8 and WP-2 total euphausiid abundance and biomass estimates were high, and ranged from 0.004 to 0.36 ind m⁻³ and 0.065 to 1.21 mg dwt m⁻³, and from 0.01 to 18.2 ind m⁻³ and 0.01 to 15.7 mg dwt m⁻³, respectively. A distinct spatial pattern in the euphausiid community was evident with the Antarctic species, Euphausia frigida, E. triacantha and E. superba predominating within the core of the eddy, while the PFZ waters were characterized by the sub-Antarctic species, E. longirostris, Stylocheiron maximum, Nematoscelis megalops and Thysanoessa gregaria. The eddy edge acted as a transition zone where species from both regions co-occurred. Within the survey area the combined ingestion rate of the six numerically dominant euphausiid species ranged between 0.02 and 5.31 μg pigm m⁻²d¹, which corresponded to a loss of between < 0.001 and 0.11 % of the available chl-a biomass. E. triacantha and juvenile T. macura were identified as the dominant grazers. There was no apparent spatial pattern in the grazing activity of the euphausiids within the region of investigation. The average daily rations of the euphausiids examined were < 2 % of their body carbon. The low daily ration of the euphausiids could be ascribed to the predominance of small picophytoplankton in the region of investigation, which are too small to be grazed efficiently by larger zooplankton. The marked spatial patterns in species composition and the elevated abundance and biomass of euphausiids, suggest that the mesoscale eddies contribute to the spatial and temporal heterogeneity of the planktonic community of the PFZ and may represent important foraging regions for many of the apex predators within the region.]]> Thu 13 May 2021 04:21:56 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:6031 Thu 13 May 2021 02:16:01 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4772 Thu 13 May 2021 02:09:29 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4188 Thu 13 May 2021 01:17:07 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3779 Thu 13 May 2021 01:14:36 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4686 Thu 13 May 2021 01:02:12 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3841 Thu 13 May 2021 00:55:31 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4964 0.60) and are poorly mineralized. The low D-values «0.40) of the well mineralized vein systems reflect the higher degree of fracture connectivity. These vein systems were capable of efficiently draining and localizing large volumes of mineralizing fluids from crustal-scale structures. A metamorphic devolatization model is proposed where the entire Damaran metasedimentary and meta-volcanic package is seen as a large source area of very low concentrations of Cu, Au and other metals. Localization of deformation into crustal-scale faults and shear zones led to regional-scale hydrothermal fluid flow and focussing into the upstream fracture networks of the Onguati study area. Strong mineralization resulted when fluids encountered the reactive marble lithologies]]> Thu 13 May 2021 00:43:54 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4436 67 > 66. Comparing porphyrazine complexes (63, 64 and 65), 63 with benzene attached to the ring, has higher triplet state lifetime (420 μs) compared to 64 and 65 containing long alkyl chain and tertbutyl substituents, 350 and 360 μs,respectively). The observed Φ[subscript]f values for 68 and 63 were quiet suprising, since low values are observed compared to the rest of the complexes (e.g 0.03 and 0.02 respectively). Although these values seem so low, they are sufficient for fluorescence imaging applications. The Φ[subscript]f values for the complexes under study are within the range reported for complexes currently used for PDT.]]> Thu 13 May 2021 00:21:54 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:4004 Thu 13 May 2021 00:20:34 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:5651 Thu 13 May 2021 00:19:52 SAST ]]> https://commons.ru.ac.za/vital/access/manager/Repository/vital:3987 Thu 13 May 2021 00:11:24 SAST ]]>