https://vital.seals.ac.za/vital/access/manager/Index ${session.getAttribute("locale")} 5 https://vital.seals.ac.za/vital/access/manager/Repository/vital:10686 1000 per annum), inshore trawling (ca. 41 per annum), shark nets (protective gill nets) (21.6 ± 6.7 per annum) and the pelagic longline fishery (5.0 ± 4.4 per annum). In contrast, leatherbacks with a pelagic lifestyle, were mostly exposed to pelagic longline fisheries (7.8 ± 7.8 per annum). A spatial analysis of fishing activities indicated that leatherback home ranges overlapped 41percent with pelagic longline fishing activity in the SA EEZ, whereas the overlap between pelagic longliners and loggerhead home ranges was 29 percent. The quantified sources of mortality provide some explanation for the trend in the loggerhead nesting population but not the trend in the leatherback nesting population. Hatchling survivorship to adulthood was estimated to determine the viability of the two nesting populations as well as to determine whether offshore mortality was responsible for the difference in recovery of the two populations. Loggerhead hatchling survivorship to adulthood was estimated at between 2 and 10 per 1000 hatchlings, the minimum requirement for an increasing population. The adopted sophisticated model shows that leatherbacks have a survival rate of 5 to 10 per 1 000 hatchlings. However, this suggests that the population is increasing, but the leatherback population is stable. Perhaps the age to maturity of SA leatherbacks is greater than 12 years, or fisheries-related mortality affects younger age classes than initially thought. It is therefore recommended that the turtle monitoring area is extended to include other potential nesting grounds. In addition, observer or monitoring programs for commercial as well as artisanal fisheries needs to be extended throughout the SWIO to quantify sea turtle mortality. Ultimately a comprehensive multi-regional approach is required for the conservation of these highly migratory species.]]> Wed 23 Jun 2021 09:43:42 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10164 Wed 12 May 2021 23:26:02 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10667 Wed 12 May 2021 23:07:05 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10474 Wed 12 May 2021 22:48:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10152 Wed 12 May 2021 22:25:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10463 Wed 12 May 2021 20:58:20 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10717 Wed 12 May 2021 20:19:17 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10580 Wed 12 May 2021 20:12:56 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10654 Wed 12 May 2021 20:09:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10135 Wed 12 May 2021 19:42:13 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10754 Wed 12 May 2021 19:39:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:16141 Wed 12 May 2021 19:36:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10157 Wed 12 May 2021 19:28:44 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10443 Wed 12 May 2021 19:22:32 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10573 Wed 12 May 2021 19:17:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10661 Wed 12 May 2021 19:09:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9663 Wed 12 May 2021 19:07:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10428 Wed 12 May 2021 18:55:46 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10343 Wed 12 May 2021 18:12:11 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10633 Wed 12 May 2021 17:55:01 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10318 Wed 12 May 2021 17:54:43 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10625 Wed 12 May 2021 17:14:35 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10664 Wed 12 May 2021 17:11:51 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10745 Wed 12 May 2021 17:10:07 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10722 Wed 12 May 2021 16:43:18 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10508 Wed 12 May 2021 16:32:14 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10629 Wed 12 May 2021 16:19:53 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10635 Wed 12 May 2021 15:49:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10632 Wed 12 May 2021 15:44:27 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10710 Thu 13 May 2021 08:16:34 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10394 Thu 13 May 2021 08:12:30 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10758 Thu 13 May 2021 08:12:21 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10511 Thu 13 May 2021 07:43:59 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10543 Thu 13 May 2021 07:18:17 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9703 Thu 13 May 2021 06:47:31 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10622 Thu 13 May 2021 06:46:42 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:29514 Thu 13 May 2021 06:41:14 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10631 Thu 13 May 2021 06:19:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10546 Vmax was noted for the thermally stressed unit. This feature in the I-V curve may be attributed to the breakdown of the Ge subcell in the CTJ cell. Based on the results obtained from the two experimental HCPV modules, recommendations for an optimal HCPV module were made.]]> Thu 13 May 2021 06:06:50 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10316 125 μg/ml. These results suggest that the extract may be selective for specific cell types. Bio-assay guided fractionation of the S. ellipticum ethanolic extract yielded two active fractions; chloroform and ethyl acetate. Two compounds isolated from the chloroform extract were screened against the three cancer cell lines and found to be inactive. Three compounds were isolated from the ethyl acetate fraction and revealed IC50 values < 62.5 and < 31 μg/ml against MCF-7. Unfortunately these two compounds soon lost activity before any further work could be done on them and work was continued with the crude extract.]]> Thu 13 May 2021 05:53:54 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10366 Thu 13 May 2021 05:24:19 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10579 Thu 13 May 2021 04:50:24 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10417 Thu 13 May 2021 04:41:08 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10517 Thu 13 May 2021 04:19:00 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10383 Thu 13 May 2021 04:14:47 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10547 Thu 13 May 2021 04:10:41 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10497 Thu 13 May 2021 04:08:55 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10721 150 percent) in the high density nesting beaches compared to the low density nesting beaches within and among seasons however further investigations are required. Artificial light (range: 0.045–0.5 lux) is an active deterrent of female emergences while ambient light, even under extreme conditions such as lightning during electric storms (up to 8.2 lux), appears to have no observable influence on the spatial or temporal distributions of emergences. Social facilitation appears unlikely as a primary nest site selection factor for loggerheads. It may however, play a minor secondary role to preferred areas or hotspots. Sea-finding in post-nesting female loggerheads appears to be driven exclusively by visual cues such as the light horizon, with minimal to no influence from other cues (the sound of the breakers, slope or smell of the ocean) which solidify the visual system’s use in sea-finding. This research on the nest site selection of loggerheads and the sensory systems involved in this process has added valuable information to the limited pool of knowledge already present and has created a solid framework on which further investigations can be based. Future work in this field should focus on integrating a suite of sensory stimuli and cues to receive a greater understanding of the sensory systems used in nest site selection.]]> Thu 13 May 2021 03:34:54 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9711 Thu 13 May 2021 03:30:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10691 Thu 13 May 2021 03:17:16 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10608 Thu 13 May 2021 03:11:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10718 Thu 13 May 2021 02:44:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10484 Thu 13 May 2021 02:40:26 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10545 Thu 13 May 2021 02:25:24 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10337 Thu 13 May 2021 02:12:58 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10421 Thu 13 May 2021 02:11:29 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:9648 Thu 13 May 2021 01:20:52 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10561 Thu 13 May 2021 01:07:12 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10623 6 mg l-1) were maintained throughout the water column mainly by wind and tidal action. However, stratification increased towards the deeper, channel-like middle and upper reaches of the estuary, followed by a significant reduction in bottom DO concentrations and development of hypoxia and anoxia. Bottom water hypoxia commonly occurs in microtidal estuaries due to the limited influence of mixing forces, mainly by wind and tidal action. The Goukamma Estuary is a channel-like microtidal estuary where stratification effectively limited oxygenation of the bottom water which resulted in frequent occurrence of bottom water hypoxia. During June 2010 when the highest local rainfall (75 mm) was recorded for the region, salinity and DO data showed that this amount of rainfall was insignificant as it did not replenish the water column of oxygen. Only the surface 0.5 m layer was fresh and oxygenated while below this, the water column was completely hypoxic. In an unimpacted state, the Goukamma Estuary is a blackwater system and is expected to be nutrient poor; however, farming activities in the catchment have resulted in elevated nutrient concentrations. This study showed that significantly higher nutrient concentrations were measured in the middle and upper reaches of the estuary, adjacent to cattle farms situated in the floodplain of these reaches. Nutrient concentrations represented mesotrophic (dissolved inorganic nitrogen [DIN] > 500 μg l-1) to eutrophic conditions (dissolved inorganic phosphorus [DIP] > 25 μg l-1). Nutrient input stimulated phytoplankton to attain a significantly high biomass, ranging between 0.3 – 112 μg l-1 (~ 7.7 ± 1.3 μg l-1; n = 128) and 0.8 – 289 μg l-1 (~ 21.1 ± 4.4 μg l-1; n = 80) during the open and closed states, respectively. High organic loads are associated with high oxygen demands which consequently result in hypoxia following decomposition. Exacerbated by natural salinity stratification which effectively limits oxygenation of the water column, unnaturally high nutrient concentrations and coinciding organic loads place the estuary at particular risk of degradation. This study captured key patterns and processes by quantifying salinity, oxygen and nutrient concentrations in addition to biological indicators (phytoplankton biomass and community composition). Considering possible budget constraints, it is recommended that monthly salinity and oxygen concentrations should be monitored as well as seasonal nutrient concentrations. It is also recommended that riparian buffer zones should be established in the middle and upper reaches of the estuary, as these vegetation buffers have been well documented to contribute to nutrient attenuation and improved water quality from agricultural run-off.]]> Thu 13 May 2021 01:05:57 SAST ]]> https://vital.seals.ac.za/vital/access/manager/Repository/vital:10649 Thu 13 May 2021 00:32:14 SAST ]]>