Factors affecting recapture rates of raggedtooth sharks Carcharias taurus tagged off the east coast of South Africa
- Authors: Dicken, Matthew L , Booth, Anthony J , Smale, Malcolm J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124493 , vital:35618 , https://doi.10.2989/AJMS.2009.31.3.9.997
- Description: Understanding differences in the recapture rate between different tags (A-, B- and C-types), capture methods (rock-and-surf anglers, scientific divers and Natal Sharks Board protection nets) and life-history stages (juvenile and adult) is critical in evaluating the results obtained from cooperative tagging programmes (CTPs). A generalised linear modelling approach, using a log-linear model, was used to determine significant differences in the probability of recapture between these various factors using data from the Oceanographic Research Institute and Port Elizabeth Museum CTPs. Between 1984 and 2004, a total of 3 385 raggedtooth sharks Carcharias taurus was tagged by volunteers from both programmes along the east coast of South Africa. A likelihood ratio test indicated significant differences in the probability of recapture between A- and C-type and B- and C-type tags (p < 0.01), between different capture methods (p < 0.05) and between juvenile and adult sharks (p < 0.01). A comparison of recapture rates between members of the CTPs also indicated a marked variability in the performance of individual taggers. The study highlights important data-quality issues inherent in large CTPs.
- Full Text:
- Date Issued: 2010
Seasonality, behaviour and philopatry of spotted ragged tooth sharks Carcharias taurus in Eastern Cape nursery areas, South Africa
- Authors: Smale, Malcolm J , Dicken, Matthew L , Booth, Anthony J
- Date: 2015
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126672 , vital:35910 , https://doi.10.2989/1814232X.2015.1043342
- Description: Spotted ragged-tooth sharks Carcharias taurus occur along the southern and eastern coasts of South Africa. We report on movements of juveniles and adults within a known nursery area on the Eastern Cape coast using acoustic telemetry. The focus area of the study was Algoa Bay, where six VEMCO VR2 ultrasonic receivers were placed at known shark aggregation sites. An additional receiver was placed at Thunderbolt Reef, approximately 2 km southwest of Cape Recife, the south-western tip of Algoa Bay. Single receivers were also deployed at Port Alfred and East London, some 45 and 170 km north-east of Algoa Bay, respectively. VEMCO acoustic V16 tags were either surgically implanted (n = 37) or attached externally using dart heads (n = 6) between January 2003 and March 2006. Surgically implanted tags were recorded over multiple months and years, whereas external tags were probably lost shortly after tagging because they were detected for very short periods. Sharks moved extensively between the sites and revisited monitored reefs over time-periods of months and years, demonstrating philopatry. Departures from and arrivals at reefs were more frequently recorded at sunset and sunrise, respectively. Sharks were detected throughout the year but they spent more time at aggregation sites during summer and autumn, indicating seasonal abundance in agreement with previous findings. Movements away from study reefs were attributed to either foraging or movements to other reefs. Despite extensive movements around the bay and beyond, both juveniles and adults exhibited philopatry to the study area over multiple years.
- Full Text:
- Date Issued: 2015
Long-term catch and effort trends in Eastern Cape Angling Week competitions
- Authors: Dicken, Matthew L , Smale, Malcolm J , Booth, Anthony J
- Date: 2012
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/124931 , vital:35711 , https://doi.org/10.2989/1814232X.2012.709961
- Description: Recreational shore-based angling is one of the most popular sport and outdoor activity pastimes in South Africa with an estimated 412 000 fishers (McGrath et al. 1997). It is a form of linefishing where fish are caught using a hook and line and comprises a social as well as a more formal organized competitive sector (van der Elst 1989). Similar to other components of the linefishery, which include the subsistence as well as boat-based commercial sectors, excessive shore-fishing effort along the Eastern Cape has resulted not only in declining catches (Bennett 1991, Griffiths 1997, Brouwer and Buxton 2002, Pradervand and Govender 2003) but also changes in the species composition of catches (Bennett et al. 1994, Brouwer et al. 1997, Attwood and Farquhar 1999). Stock assessments indicate that many important linefish species are severely overexploited (Griffiths 1997, Hutchings 2000, Mann 2000) and that continued fishing pressure threatens endemic linefish populations. In 1996, shore-anglers alone were responsible for an annual catch of approximately 4.5 million fish, weighing around 3 000 tonnes (Brouwer et al. 1997).
- Full Text:
- Date Issued: 2012
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
- Authors: Dicken, Matthew Laurence , Booth, Anthony J , Smale, Malcolm John
- Date: 2006
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/125774 , vital:35816 , https://doi.10.1016/j.icesjms.2006.06.009
- Description: Mark-recapture models do not distinguish how ‘‘deaths’’ accrue to marked animals in the population. If animals lose their tags, then recaptures will be fewer than expected and estimates of survival will be underestimated (Arnason and Mills, 1981; McDonald et al., 2003). Similarly, if the non-reporting rate is unknown and assumed to be negligible, as is the case in some tagging studies (e.g. Cliff et al., 1996, for white sharks Carcharodon carcharias), the probability of capture can be underestimated. The effects of both these problems, inherent in cooperative tagging programmes, lead to too few tagged fish being recovered, with a positive bias on the estimation of population size. These effects are most pronounced when capture probability is low and fewer tags are available for recapture (McDonald et al., 2003).
- Full Text:
- Date Issued: 2006
Spatial and seasonal distribution patterns of the ragged-tooth shark Carcharias taurus along the coast of South Africa
- Authors: Dicken, Matthew L , Booth, Anthony J , Smale, Malcolm J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/127008 , vital:35943 , https://doi.10.2989/18142320609504210
- Description: Off South Africa, the ragged-tooth shark Carcharias Taurus has been occasionally reported from the West Coast, but it is more commonly found along the East and South coasts from Cape Town to northern KwaZulu-Natal (KZN) (Bass et al. 1975, Smale 2002). Mating is thought to occur off the south coast of KZN from October to late November (G Cliff, Natal Sharks Board, unpublished data). Pregnant females then move northward to spend the early part of their gestation in the warmer waters of northern KZN and possibly southern Moçambique. During July and August, the near-term pregnant females begin to move southwards towards the cooler waters of the Eastern Cape (Wallett 1973, Bass et al. 1975, G Cliff, unpublished data), where they give birth from September to November (Smale 2002). After parturition, many of the females migrate back to KZN. The whereabouts of mature males outside of the mating season is unclear. These broadscale distribution and migratory habits for C. taurus have been inferred from limited catch records obtained for only parts of its range along the South African coast.
- Full Text:
- Date Issued: 2010
Shark fishing effort and catch of the ragged-tooth shark Carcharias taurus in the South African competitive shore-angling fishery
- Authors: Dicken, Matthew L , Booth, Anthony J , Smale, Malcolm J
- Date: 2010
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/126944 , vital:35937 , https://doi.10.2989/18142320609504209
- Description: In South Africa, Carcharias taurus is commonly known as the ragged-tooth shark or raggie. The species is also referred to as the sand-tiger shark in North America and as the grey-nurse shark in Australia. It is a long-lived species with an estimated longevity of up to 40 years (Goldman 2002). Female sharks reach sexual maturity at approximately 10 years (Goldman 2002), and they exhibit a biennial reproductive cycle (Branstetter and Musick 1994, Lucifora et al. 2002, G Cliff, Natal Sharks Board, unpublished data). Intra-uterine cannibalisation results in a maximum fecundity of two pups per litter after a gestation period of approximately 9–12 months (Bass et al. 1975, Gilmore et al. 1983). These life-history characteristics make this species particularly susceptible to overexploitation.
- Full Text:
- Date Issued: 2010
Pessimistic assessment of white shark population status in South Africa: comment on Andreotti et al.(2016)
- Authors: Irion, Dylan T , Noble, Leslie R , Kock, Alison A , Gennari, Enrico , Dicken, Matthew L , Hewitt, Adrian M , Towner, Alison V , Booth, Anthony J , Smale, Malcolm J , Cliff, Geremy
- Date: 2017
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/${Handle} , vital:35799 , https://doi.10.3354/meps12283
- Description: Andreotti et al. (2016; Mar Ecol Prog Ser 552:241−253) estimate an abundance (N) of 438 white sharks Carcharodon carcharias and a contemporary effective population size (CNe) of 333 individuals along the South African coast. N was estimated by using a mark-recapture analysis of photographic identification records from a single aggregation site (Gansbaai). CNe was calculated based on the levels of pairwise linkage disequilibrium of genetic material collected from 4 aggregation sites across approximately 965 km of South African coastline. However, due to the complex stock structure of white sharks and the model assumptions made by Andreotti et al. (2016), the conclusions drawn cannot be supported by their methods and data.
- Full Text:
- Date Issued: 2017
The disparities arising in the policing of consumptive and non-consumptive marine activities
- Authors: Tembo, Danai
- Date: 2010
- Subjects: Marine resources conservation -- South Africa , Fishery law and legislation -- South Africa
- Language: English
- Type: Thesis , Masters , MBA
- Identifier: vital:8649 , http://hdl.handle.net/10948/1383 , Marine resources conservation -- South Africa , Fishery law and legislation -- South Africa
- Description: The South African marine environment is utilised for both consumptive and non-consumptive activities and for those activities to continue sustainably it is important that these activities be monitored and policed. South Africa's environmental legislation is structured to do just that; outlining specific regulations for all consumptive and non-consumptive activities that can be conducted in the marine environment. Some disparities have been observed regarding the policing of consumptive and non-consumptive marine activities, and these disparities were analysed by means of several case studies and semi-structured key informant interviews. Case studies covered both consumptive (abalone poaching and Illegal, Unreported and Unregulated fishing) and non-consumptive activities (the sardine run and tiger shark diving) currently being conduct in the marine environment. Key informant interviews collected opinions from legal practitioners who felt that the legislation was solid but poorly implemented; and non-consumptive operators who felt that the legislation was implemented in a way that made it difficult for non-consumptive and ecotourism activities to thrive. The poor implementation has resulted in a situation which seems to promote consumptive crimes instead of curbing them.
- Full Text:
- Date Issued: 2010
Group problem solving among community activists in a South African setting: an everyday cognition approach
- Authors: Van Vlaenderen, Hilde
- Date: 1998
- Subjects: Group problem solving Group problem solving -- South Africa Cross-cultural studies -- Methodology Cognition Cross-cultural studies Cognition -- Research
- Language: English
- Type: Thesis , Doctoral , PhD
- Identifier: vital:3080 , http://hdl.handle.net/10962/d1002589
- Description: The study focuses on the everyday problem solving processes of a group of community activists in a rural setting in the Eastern Cape Province of South Africa. It aims to uncover: first, the local knowledge of the participants of the study with reference to the concepts problem and problem solving; second, the participants' group problem solving procedure; and third, the dialectical interrelation between the participants' knowledge and practice with reference to everyday group problem solving. It is contended that the mainstream cognitive approach and the cross-cultural tradition are inappropriate for the study of everyday cognitive processes. A ‘situated cognition’ approach, based on the notions of activity and cultural mediation, is proposed as a theoretical framework for the study. The ontological and epistemological assumptions underpinning the empirical study were derived from a scientific realist and a hermeneutical paradigm. Data for the inquiry into the local knowledge of the participants was collected through individual interviews. The data was interpreted, using the grounded theory techniques of constant comparison, coding and compiling theoretical diagrams. Data for the inquiry into the participants' group problem solving practice consisted of video-taped group problem solving processes. This data was analysed, using a multi layered process of progressively deeper interpretation, employing a reading guide technique. Analysis of the research data revealed that the participants perceived a problem as an impediment to satisfactory participation in society. Problem solving was considered as an emotive, cognitive and inter-active process, involving particular role players. This process had a certain structure, involved attitudes and actions and relied on particular resources. Successful problem solving was perceived to result in restoration of social equilibrium. The group problem solving procedure used by the participants consisted of a process of developing a common understanding and group consensus. The strategies employed in the process, the roles played by the participants, the rules adhered to by the participants and the structure underlying the process were all congruent with these aims. There was a mutually reinforcing interrelation between knowledge and practice with reference to the participants’ problem solving.
- Full Text:
- Date Issued: 1998
TB spine children on their frames at St Matthews Hospital
- Subjects: St. Matthew's College (Keiskammahoek, South Africa) -- Photographs St. Matthew's Mission (Keiskammahoek, South Africa) -- Photographs Tuberculosis in children -- South Africa -- Keiskammahoek -- Photographs St. Matthew's Hospital (Eastern Cape, South Africa) -- Photographs St. Matthew's Mission School (Keiskammahoek, South Africa) -- Athletics -- Photographs St. Matthew's Mission School (Keiskammahoek, South Africa) -- Sports -- Photographs
- Type: Image
- Identifier: http://hdl.handle.net/10962/35747 , vital:24396 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017 , PIC 5013
- Description: A photograph album showing views of buildings and people at St Michaels and St. Matthews Missions in Keiskammahoek, South Africa. The album was donated to Cory Library by Mariaan George of Roeland Street, Cape Town. This photograph shows nurses and children who suffered from spinal tuberculosis lying on their special orthopedic frames at St Matthews Hospital
- Full Text: false
Sports Day at St. Matthews Mission School - spectators
- Subjects: St. Matthew's College (Keiskammahoek, South Africa) -- Photographs St. Matthew's Mission (Keiskammahoek, South Africa) -- Photographs St. Michael's Mission (Eastern Cape, South Africa) -- Photographs St. Matthew's Hospital (Eastern Cape, South Africa) -- Photographs St. Matthew's Mission School (Keiskammahoek, South Africa) -- Athletics -- Photographs St. Matthew's Mission School (Keiskammahoek, South Africa) -- Sports -- Photographs
- Type: Image
- Identifier: http://hdl.handle.net/10962/35705 , vital:24391 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017 , PIC 5012
- Description: A photograph album showing views of buildings and people at St Michaels and St. Matthews Missions in Keiskammahoek, South Africa. The album was donated to Cory Library by Mariaan George of Roeland Street, Cape Town. This photograph shows spectators watching sports event at St Matthews Mission during their annual sports day
- Full Text: false
Women and child at Sports Day in St. Matthews
- Subjects: St. Matthew's College (Keiskammahoek, South Africa) -- Photographs St. Matthew's Mission (Keiskammahoek, South Africa) -- Photographs St. Matthew's Hospital (Eastern Cape, South Africa) -- Photographs St. Matthew's Mission School (Keiskammahoek, South Africa) -- Athletics -- Photographs St. Matthew's Mission School (Keiskammahoek, South Africa) -- Sports -- Photographs
- Type: Image
- Identifier: http://hdl.handle.net/10962/35771 , vital:24398 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017 , PIC 5014
- Description: A photograph album showing views of buildings and people at St Michaels and St. Matthews Missions in Keiskammahoek, South Africa. The album was donated to Cory Library by Mariaan George of Roeland Street, Cape Town. This photograph shows two local African women wearing their traditional garb, and an infant sleeping on the ground. They have come to watch sport events at St Matthews
- Full Text: false
Children's Christmas Party - smiling boy
- Subjects: St. Matthew's College -- Photographs St. Matthew's Mission (Keiskammahoek, South Africa) -- Photographs St. Michael's Mission (Eastern Cape, South Africa) -- Photographs St Matthew's Hospital (Eastern Cape, South Africa) -- Photographs
- Type: Image
- Identifier: http://hdl.handle.net/10962/34391 , vital:24241 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017 , PIC 5003
- Description: A photograph album showing views of buildings and people at St Michaels and St Matthews Missions in Keiskammahoek, South Africa. The album was donated to Cory Library by Mariaan George of Roeland Street, Cape Town
- Full Text: false
Hospital washing
- Subjects: St. Matthew's College -- Photographs St. Matthew's Mission (Keiskammahoek, South Africa) -- Photographs St. Michael's Mission (Eastern Cape, South Africa) -- Photographs St Matthew's Hospital (Eastern Cape, South Africa) -- Photographs
- Type: Image
- Identifier: http://hdl.handle.net/10962/34423 , vital:24244 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017 , PIC 5006
- Description: A photograph album showing views of buildings and people at St Michaels and St Matthews Missions in Keiskammahoek, South Africa. The album was donated to Cory Library by Mariaan George of Roeland Street, Cape Town. This photograph is showing three African women, hospital workers doing laundry outside
- Full Text: false
Xhosa beauty (woman)
- Subjects: Xhosa (African People) -- Photographs Women, Xhosa -- Photographs St. Matthew's Hospital (Eastern Cape, South Africa) -- Photographs St. Matthew's Mission School (Keiskammahoek, South Africa) -- Athletics -- Photographs St. Matthew's Mission School (Keiskammahoek, South Africa) -- Sports -- Photographs
- Type: Image
- Identifier: http://hdl.handle.net/10962/35798 , vital:24400 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017 , PIC 5015
- Description: A photograph album showing views of buildings and people at St Michaels and St. Matthews Missions in Keiskammahoek, South Africa. The album was donated to Cory Library by Mariaan George of Roeland Street, Cape Town. This photograph shows a local Xhosa woman. She is wearing a doek around her head to show that she is married
- Full Text: false
Pupils at Armstrong House playing outside
- Subjects: St. Matthew's College -- Photographs , St. Matthew's Mission (Keiskammahoek, South Africa) -- Photographs , St. Michael's Mission (Eastern Cape, South Africa) -- Photographs , St Matthew's Hospital (Eastern Cape, South Africa) -- Photographs
- Type: Image
- Identifier: http://hdl.handle.net/10962/35411 , vital:24363 , PIC 5009
- Description: A photograph album showing views of buildings and people at St Michaels and St Matthews Missions in Keiskammahoek, South Africa. The album was donated to Cory Library by Mariaan George of Roeland Street, Cape Town. This photograph is showing pupils in one of the dormitories at St Matthews, playing outside
- Full Text: false
Healed PTB Happiness
- Subjects: St. Matthew's College -- Photographs St. Matthew's Mission (Keiskammahoek, South Africa) -- Photographs St. Michael's Mission (Eastern Cape, South Africa) -- Photographs St Matthew's Hospital (Eastern Cape, South Africa) -- Photographs
- Type: Image
- Identifier: http://hdl.handle.net/10962/34413 , vital:24243 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017 , PIC 5005
- Description: A photograph album showing views of buildings and people at St Michaels and St Matthews Missions in Keiskammahoek, South Africa. The album was donated to Cory Library by Mariaan George of Roeland Street, Cape Town. This photograph is showing a boy, one of the TB patients to be treated at St Matthews Hospital. He is smiling probably because he is now healed and is free from TB
- Full Text: false
Patients transport to hospital
- Subjects: St. Matthew's College -- Photographs St. Matthew's Mission (Keiskammahoek, South Africa) -- Photographs St. Michael's Mission (Eastern Cape, South Africa) -- Photographs St Matthew's Hospital (Eastern Cape, South Africa) -- Photographs
- Type: Image
- Identifier: http://hdl.handle.net/10962/35316 , vital:24352 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017 , PIC 5008
- Description: A photograph album showing views of buildings and people at St Michaels and St Matthews Missions in Keiskammahoek, South Africa. The album was donated to Cory Library by Mariaan George of Roeland Street, Cape Town. This photograph is showing a sledge pulled by oxen, transporting patients to hospital, with a young boy leading the sledge
- Full Text: false
Second year students at Armstrong House - trophy presentation
- Subjects: St. Matthew's College -- Photographs St. Matthew's Mission (Keiskammahoek, South Africa) -- Photographs St. Michael's Mission (Eastern Cape, South Africa) -- Photographs St Matthew's Hospital (Eastern Cape, South Africa) -- Photographs
- Type: Image
- Identifier: http://hdl.handle.net/10962/34373 , vital:24239 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017 , PIC 5001
- Description: A photograph album showing views of buildings and people at St Michaels and St Matthews Missions in Keiskammahoek, South Africa. The album was donated to Cory Library by Mariaan George of Roeland Street, Cape Town
- Full Text: false
Eric Abbhah, Dean of Westminster with Dorah John Jane watching local women stamping mealies
- Subjects: St. Matthew's College -- Photographs St. Matthew's Mission (Keiskammahoek, South Africa) -- Photographs St. Michael's Mission (Eastern Cape, South Africa) -- Photographs St Matthew's Hospital (Eastern Cape, South Africa) -- Photographs
- Type: Image
- Identifier: http://hdl.handle.net/10962/34403 , vital:24242 , This image is held at the Cory Library for Humanities Research at Rhodes University. For further information contact cory@ru.ac.za. The digitisation of this image was made possible through a generous grant received from the Andrew W. Mellon Foundation 2014-2017 , PIC 5004
- Description: A photograph album showing views of buildings and people at St Michaels and St Matthews Missions in Keiskammahoek, South Africa. The album was donated to Cory Library by Mariaan George of Roeland Street, Cape Town
- Full Text: false