Estimates of juvenile and adult raggedtooth shark (Carcharias taurus) abundance along the east coast of South Africa

2008 ◽  
Vol 65 (4) ◽  
pp. 621-632 ◽  
Author(s):  
Matthew Laurence Dicken ◽  
Anthony John Booth ◽  
Malcolm John Smale
Keyword(s):  
South Africa ◽  
East Coast ◽  
Adult Survival ◽  
Juvenile Survival ◽  
Tag Loss ◽  
Oceanographic Research ◽  
The Mean ◽  
Juvenile Sharks ◽  
Carcharias Taurus ◽  
Probability Of Capture

A Cormack–Jolly–Seber model was developed to estimate abundance, survival, and probability of capture for juvenile (<1.8 m total length, TL) and adult (>1.8 m TL) raggedtooth sharks (Carcharias taurus) along the east coast of South Africa. Model estimates were adjusted to account for tag loss, nonreporting, and after release mortality. The model was constructed using mark–recapture data from the Oceanographic Research Institute and Port Elizabeth Museum cooperative tagging programs from 1984 to 2004. The adjusted estimate for juvenile survival was 0.56 and that for adult survival was 0.89. The adjusted estimate of probability of capture for juvenile sharks ranged from 0.06 to 0.17, while that for adult sharks was from 0.02 to 0.04. The mean annual abundance of juvenile sharks was 6800 (coefficient of variation, CV = 13%) and adult sharks 16 700 (CV = 9%). The accumulated effect of tag loss, nonreporting, and after release mortality were to reduce the overall estimate of juvenile and adult abundance by approximately 50%. The adjusted estimate of population size for both juvenile and adult sharks over the last decade appears to have remained constant (P > 0.05).

scholarly journals Preliminary observations of tag shedding, tag reporting, tag wounds, and tag biofouling for raggedtooth sharks (Carcharias taurus) tagged off the east coast of South Africa

2006 ◽  
Vol 63 (9) ◽  
pp. 1640-1648 ◽  
Author(s):  
M.L. Dicken ◽  
A.J. Booth ◽  
M.J. Smale
Keyword(s):  
South Africa ◽  
East Coast ◽  
Telephone Survey ◽  
Total Length ◽  
Significant Difference ◽  
Juvenile Sharks ◽  
Carcharias Taurus ◽  
Tag Shedding

Abstract A double-tagging experiment and integrated on-site questionnaire and telephone survey were used to investigate aspects of tag shedding, tag reporting, tag wounds, and tag biofouling for the raggedtooth shark (Carcharias taurus), tagged off the east coast of South Africa. Between 2002 and 2004, 84 juvenile (<1.8 m total length, TL), and 24 adult (>1.8 m TL) C. taurus were double-tagged. Of these, 11 juvenile and six adult double-tagged sharks were recaptured. Significantly, more tags were shed from adult than from juvenile sharks, and there was also a significant difference between the number of anterior and posterior tags shed. Rates of tag reporting were estimated from a survey of 477 randomly selected shore-anglers, and they varied both temporally and spatially from 27% to 100%. In all, 93 tag recaptures were reported in the survey, most (75.3%) with some biofouling. Tag-inflicted damage was reported in 35.5% of recaptured sharks, and the incidence of tag-inflicted damage was greater for disk (77.8%) than for dart tags (25.3%).

Spatial and seasonal distribution patterns of juvenile and adult raggedtooth sharks (Carcharias taurus) tagged off the east coast of South Africa

2007 ◽  
Vol 58 (1) ◽  
pp. 127 ◽  
Author(s):  
M. L. Dicken ◽  
A. J. Booth ◽  
M. J. Smale ◽  
G. Cliff
Keyword(s):  
South Africa ◽  
East Coast ◽  
Average Rate ◽  
Anthropogenic Activities ◽  
Average Distance ◽  
Movement Patterns ◽  
Release Site ◽  
Distribution Patterns ◽  
Juvenile Sharks ◽  
Carcharias Taurus

Understanding the movement patterns of raggedtooth sharks (Carcharias taurus) is crucial in defining habitat use and evaluating the effects of exploitation and anthropogenic activities. Between 1984 and 2004, 1107 C. taurus juveniles (<1.8-m TL) and 2369 C. taurus maturing subadults and adults (>1.8-m TL) were tagged and released along the east coast of South Africa. In total, 125 C. taurus juveniles and 178 C. taurus maturing subadults and adults were recaptured, representing recapture rates of 11.2% and 7.5% respectively. The average distance travelled by juvenile sharks was 18.7 km (95% CI = 10.8–26.6 km). Juvenile sharks displayed site fidelity to summer nursery areas. The average distance travelled by maturing and adult sharks was 342 km (95% CI = 275–409 km). One female shark, however, was recaptured 1897 km from its original release site. The average rate at which pregnant sharks moved south from their gestation to pupping grounds was 2.6 km day–1 (95% CI = 2.04–3.16 km day–1). This study highlights the differences in movement patterns between C. taurus juveniles and adults and suggests philopatric behaviour in both life-history stages.

Possible maternal offloading of metals in the plasma, uterine and capsule fluid of pregnant ragged-tooth sharks (Carcharias taurus) on the east coast of South Africa

2017 ◽  
Vol 24 (20) ◽  
pp. 16798-16805 ◽  
Author(s):  
Kristina Naidoo ◽  
Anil Chuturgoon ◽  
Geremy Cliff ◽  
Sanil Singh ◽  
Megan Ellis ◽  
...  
Keyword(s):  
South Africa ◽  
East Coast ◽  
Carcharias Taurus

Laparotomy for Abdominal Stab Wound With Combined Omental and Organ Evisceration: 10-Year Experience From a Major Trauma Centre in South Africa

2021 ◽  
pp. 000313482110318
Author(s):  
Victor Kong ◽  
Cynthia Cheung ◽  
Nigel Rajaretnam ◽  
Rohit Sarvepalli ◽  
William Xu ◽  
...  
Keyword(s):  
South Africa ◽  
Small Bowel ◽  
Large Bowel ◽  
Major Trauma ◽  
Stab Wound ◽  
Length Of Hospital Stay ◽  
Trauma Centre ◽  
Major Trauma Centre ◽  
The Mean ◽  
Overall Mortality

Introduction Combined omental and organ evisceration following anterior abdominal stab wound (SW) is uncommon and there is a paucity of literature describing the management and spectrum of injuries encountered at laparotomy. Methods A retrospective study was undertaken on all patients who presented with anterior abdominal SW involving combined omental and organ evisceration who underwent laparotomy over a 10-year period from January 2008 to January 2018 at a major trauma centre in South Africa. Results A total of 61 patients were eligible for inclusion and all underwent laparotomy: 87% male, mean age: 29 years. Ninety-two percent (56/61) had a positive laparotomy whilst 8% (5/61) underwent a negative procedure. Of the 56 positive laparotomies, 91% (51/56) were considered therapeutic and 9% (5/56) were non-therapeutic. In addition to omental evisceration, 59% (36/61) had eviscerated small bowel, 28% (17/61) had eviscerated colon and 13% (8/61) had eviscerated stomach. A total of 92 organ injuries were identified. The most commonly injured organs were small bowel, large bowel and stomach. The overall complication rate was 11%. Twelve percent (7/61) required intensive care unit admission. The mean length of hospital stay was 9 days. The overall mortality rate for all 61 patients was 2%. Conclusions The presence of combined omental and organ evisceration following abdominal SW mandates laparotomy. The small bowel, large bowel and stomach were the most commonly injured organs in this setting.

scholarly journals 24-Hour Measurement of Gastric pH in Rural South Africa

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Alastair M. Sammon ◽  
Eugene J. Ndebia ◽  
Ekambaram Umapathy ◽  
Jehu E. Iputo
Keyword(s):  
South Africa ◽  
Ambulatory Monitoring ◽  
Duodenogastric Reflux ◽  
Lower Oesophageal Sphincter ◽  
Gastric Ph ◽  
Night Time ◽  
High Incidence ◽  
The Mean ◽  
H Pylori ◽  
High Level

Background. Previous studies have established norms of 24-hour gastric pH profiles for western countries. This study was designed to establish the pattern for a rural African population with a high incidence of oesophageal cancer.Methods. After lower oesophageal manometry a probe was placed 10 cm distal to the lower oesophageal sphincter. We carried out 24-hour ambulatory monitoring of gastric pH on 59 healthy subjects. This was satisfactorily completed on 26 female and 18 male (age 21–64, median 35) subjects in the Transkei region of South Africa.Results. The mean 24 hour gastric pH was 2.84 and the mean night-time pH was 3.7. 40 volunteers recorded a night-time pH reaching over 4. 33 volunteers recorded a night-time pH over 7. Night-time alkalinisation was present for 136.4 minutes (25th centile 22.8, 75th centile 208.1) at pH4 or over, and 79.3 (2.5, 122.7) minutes at pH7 or over. Episodes of rapid alkaline rise were 17 (10, 47). 21.1% of these occurred while supine. 35 of 36 tested subjects were positive forH. pyloriIgG.Conclusion. Gastric alkalinisation is common in Transkei, at a higher pH than that reported in other studies, and is sustained longer. Nighttime alkalinisation is frequent. This suggests a high level of duodenogastric reflux.

scholarly journals Population irruption of the clam Meretrix morphina in Lake St Lucia, South Africa

2017 ◽  
Vol 113 (7/8) ◽  
Author(s):  
Nelson A. F. Miranda ◽  
Nasreen Peer ◽  
Renzo Perissinotto ◽  
Nicola K. Carrasco ◽  
Salome Jones ◽  
...  
Keyword(s):  
South Africa ◽  
South African ◽  
East Coast ◽  
Severe Drought ◽  
Freshwater Input ◽  
Large Populations ◽  
Ocean Region ◽  
West Indian Ocean ◽  
First Time ◽  
Eastern Seaboard

The thick-shelled clam Meretrix morphina, previously referred to as Meretrix meretrix, now occurs in the west Indian Ocean region, along the eastern seaboard of Africa, from the Red Sea to the Mlalazi Estuary, close to the Tugela River. Its presence in South Africa is only of recent recording. Meretrix morphina was detected for the first time in Lake St Lucia in 2000. The population declined and was not detected from 2005 until 2011, most likely as a result of a severe drought that resulted in widespread desiccation and hypersalinity in the lake. The system then experienced increased freshwater input resulting in lower salinities from 2011 until 2014, during which time M. morphina reappeared and their population gradually increased. In 2015, M. morphina became abundant in St Lucia, attaining unprecedented densities of 447 ind./m2. Biomass, expressed as a fresh weight, varied in the different basins of St Lucia, ranging from 195 g/m2 at Lister’s Point to 1909.8 g/m2 at Catalina Bay. However, in 2016, when drought conditions returned, M. morphina disappeared. This species appears to thrive under brackish salinities and high temperatures. It is able to establish large populations with high biomass and can become dominant. However, M. morphina is sensitive to desiccation and hypersaline conditions. This clam has substantial commercial value and is exploited along the African east coast, particularly in Mozambique. In future, it may feature more prominently in South African estuaries. However, the ecology of M. morphina is still largely unknown.

scholarly journals Palaeoclimates: the first two billion years

2006 ◽  
Vol 361 (1470) ◽  
pp. 917-929 ◽  
Author(s):  
James F Kasting ◽  
Shuhei Ono
Keyword(s):  
South Africa ◽  
Oxygen Isotopes ◽  
Natural Explanation ◽  
Witwatersrand Basin ◽  
Late Archaean ◽  
Bacterial Sulphate Reduction ◽  
Climatic Constraints ◽  
The Mean ◽  
High Concentrations ◽  
Earth’S Climate

Earth's climate during the Archaean remains highly uncertain, as the relevant geologic evidence is sparse and occasionally contradictory. Oxygen isotopes in cherts suggest that between 3.5 and 3.2 Gyr ago (Ga) the Archaean climate was hot (55–85 °C); however, the fact that these cherts have experienced only a modest amount of weathering suggests that the climate was temperate, as today. The presence of diamictites in the Pongola Supergroup and the Witwatersrand Basin of South Africa suggests that by 2.9 Ga the climate was glacial. The Late Archaean was relatively warm; then glaciation (possibly of global extent) reappeared in the Early Palaeoproterozoic, around 2.3–2.4 Ga. Fitting these climatic constraints with a model requires high concentrations of atmospheric CO 2 or CH 4 , or both. Solar luminosity was 20–25% lower than today, so elevated greenhouse gas concentrations were needed just to keep the mean surface temperature above freezing. A rise in O 2 at approximately 2.4 Ga, and a concomitant decrease in CH 4 , provides a natural explanation for the Palaeoproterozoic glaciations. The Mid-Archaean glaciations may have been caused by a drawdown in H 2 and CH 4 caused by the origin of bacterial sulphate reduction. More work is needed to test this latter hypothesis.

scholarly journals Prevalence of zinc deficiency among primary school children in a poor peri-urban informal settlement in South Africa

2010 ◽  
Vol 15 (1) ◽  
Author(s):  
Folake O. Samuel ◽  
Abdulkadir A. Egal ◽  
Wilna H. Oldewage-Theron ◽  
Carin E. Napier ◽  
Christine S. Venter
Keyword(s):  
Social Sciences ◽  
South Africa ◽  
Zinc Deficiency ◽  
Informal Settlement ◽  
Serum Zinc ◽  
Primary School Children ◽  
World Health ◽  
Food Sources ◽  
Cross Sectional ◽  
The Mean

This cross-sectional study assessed the risk of zinc deficiency in randomly selected children, aged between 7 and 11 years, living in a poor, peri-urban informal settlement in South Africa. Dietary intake of 149 respondents was evaluated by 24-hour recall and quantitative food frequency questionnaires. Anthropometric and biochemical indices of a subset of 113 were determined. Descriptive statistics, analysis of variance and Pearson correlations were computed using the Statistical Package for Social Sciences, version 14.0. Anthropometric data were analysed using the World Health Organization Anthro plus version 1.0.2 statistical software. Dietary data were analysed with FoodFinder® version 3. The mean age of the children was 9.0±1.1 years. Few zinc-rich sources appeared in the diet that was predominantly plant-based. Mean dietary zinc intake was 4.6±2.2 mg/day. The mean value of serum zinc was 66.4±21.5 µg/dL, with 46% of the children having values less than the 70 µg/dL cut-off. The findings indicate a high risk of zinc deficiency and suboptimal zinc status for the majority of this study population of children, possibly as a result of low consumption of food sources with high bioavailability of zinc, which invariably is a direct consequence of poverty and food insecurity.OpsommingDie doel van hierdie dwarsdeursnitstudie was die bepaling van die risiko van ’n sinktekort in ’n ewekansige steekproef van 7 tot 11 jaar-oue kinders, woonagtig in ’n arm, voorstedelike informele woonbuurt in Suid Afrika. Dieetinnames van 149 respondente is geëvalueer deur 24-uur herroep en kwantitatiewe voedselfrekwensie vraelyste. Antropometriese en biochemiese indikatore van ’n kleiner steekproef van 113 is ook bepaal. Beskrywende statistiek, analise van variansie en Pearsonkorrelasies is bepaal deur die Statistical Package for Social Sciences, uitgawe 14.0. Antropometriese data is geanaliseer deur die statistiese program, Anthro plus, uitgawe 1.0.2, van die Wêreld Gesondheid Organisasie. Dieetdata is met behulp van FoodFinder® uitgawe 3 geanaliseer. Die gemiddelde ouderdom van die kinders was 9.0±1.1 jaar. Min sinkryke voedselbronne is in die hoofsaaklik plantryke dieet waargeneem. Die gemiddelde sinkinname was 4.6±2.2 mg/dag en die gemiddelde serumsinkwaarde was 66.4±21.5 µg/dL, met 46% van die kinders se waardes onder die 70 µg/dL afsnypunt. Die bevindings dui op ’n hoë risiko vir sinktekort en suboptimale sinkstatus vir die meerderheid van hierdie kinders, moontlik as gevolg van die swak inname van voedselbronne met hoë biobeskikbare sink, wat gewoonlik ’n direkte gevolg van armoede en huishoudelike voedsel insekuriteit is.

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