Nursery grounds, movement patterns and growth rates of dusky sharks, Carcharhinus obscurus: a long-term tag and release study in South African waters

2009 ◽  
Vol 60 (6) ◽  
pp. 571 ◽  
Author(s):  
Nigel E. Hussey ◽  
Ian D. McCarthy ◽  
Sheldon F. J. Dudley ◽  
Bruce Q. Mann
Keyword(s):  
South African ◽  
Growth Rates ◽  
Movement Patterns ◽  
Small Scale ◽  
Shark Species ◽  
Early Life Stages ◽  
Kwazulu Natal ◽  
Management Plans ◽  
Carcharhinus Obscurus

Knowledge of movement patterns of sharks in coastal waters is critical for the structuring of regional management plans. Through a long-term tag–recapture program, 9716 dusky sharks (Carcharhinus obscurus) were tagged and released along the east coast of South Africa. A total of 648 C. obscurus, principally small sharks (<100 cm PCL), were recaptured. Most recaptures were within 100 km of the tagging location in the nursery habitat in KwaZulu-Natal (KZN) with small scale movements occurring throughout the year. Forty-eight C. obscurus undertook movements >200 km that indicated a southerly migration between KZN and Eastern/Southern Cape (E/SC) between June and November. Seasonal northerly migrations were less well defined. The largest southerly and northerly movements were 1323 km and 1374 km, respectively. For sharks moving 1–100 km south from their tagging locality in KZN, an increase in displacement occurred between June and September identifying animals beginning their migration to the E/SC. With increasing displacement, there was also an increase in minimum swimming speed. Calculated growth rates of small sharks of 10.3–11.5 cm year–1 were in agreement with current literature values. Established tag–recapture programs provide an important tool in understanding the ecology of early life-stages of coastal shark species.

scholarly journals Online appendix 1:Collection stewardship constrained by resources: The management of religious archives in Pietermaritzburg, KwaZulu-Natal region

2013 ◽  
Vol 34 (1) ◽  
Author(s):  
Francis Garaba
Keyword(s):  
South Africa ◽  
South African ◽  
African Society ◽  
The South ◽  
South African Society ◽  
Online Appendix ◽  
Kwazulu Natal ◽  
To Come ◽  
The Voice

A survey using questionnaires, observation and interviews was conducted in 2011 to ascertain the collection stewardship strategies of archival repositories with religious archives in Pietermaritzburg. The study concluded that there was a need to establish a religious archives group in order for the voice of ecclesiastical archives to resonate across South Africa. Through this group, it is hoped that there will be greater coordination and networking amongst the archival repositories. The help of associations such as the South African Society of Archivists, the Oral History Association of South Africa and the South African Preservation Group could greatly assist in fostering best practices in archival management. To champion this worthwhile cause, it would be ideal to come up with an Open Day on religious archives to serve as an advocacy platform. These recommendations are made against a backdrop of the poor state of religious archives in Pietermaritzburg, resulting from acute underfunding and which threatens the survival of this record in the long term.

scholarly journals Online appendix 2:Collection stewardship constrained by resources: The management of religious archives in Pietermaritzburg, KwaZulu-Natal region

2013 ◽  
Vol 34 (1) ◽  
Author(s):  
Francis Garaba
Keyword(s):  
South Africa ◽  
South African ◽  
African Society ◽  
The South ◽  
South African Society ◽  
Online Appendix ◽  
Kwazulu Natal ◽  
To Come ◽  
The Voice

A survey using questionnaires, observation and interviews was conducted in 2011 to ascertain the collection stewardship strategies of archival repositories with religious archives in Pietermaritzburg. The study concluded that there was a need to establish a religious archives group in order for the voice of ecclesiastical archives to resonate across South Africa. Through this group, it is hoped that there will be greater coordination and networking amongst the archival repositories. The help of associations such as the South African Society of Archivists, the Oral History Association of South Africa and the South African Preservation Group could greatly assist in fostering best practices in archival management. To champion this worthwhile cause, it would be ideal to come up with an Open Day on religious archives to serve as an advocacy platform. These recommendations are made against a backdrop of the poor state of religious archives in Pietermaritzburg, resulting from acute underfunding and which threatens the survival of this record in the long term.

Residency, space use and movement patterns of juvenile sandbar sharks (Carcharhinus plumbeus) within a Virginia summer nursery area

2010 ◽  
Vol 61 (2) ◽  
pp. 223 ◽  
Author(s):  
C. L. Conrath ◽  
J. A. Musick
Keyword(s):  
Movement Patterns ◽  
Nursery Area ◽  
Small Scale ◽  
Shark Species ◽  
Eastern Shore ◽  
Carcharhinus Plumbeus ◽  
Near Shore ◽  
Passive Acoustic ◽  
Conservation And Management ◽  
Juvenile Sharks

Neonates and juveniles of many large coastal shark species occupy shallow inshore nursery areas during portions of the year. The identification of how these areas are used by large coastal shark populations is an important consideration in conservation and management efforts. An array of passive acoustic receivers was utilised to track the movements of 64 neonate and juvenile sandbar sharks within the Eastern Shore of Virginia summer nursery during the summers of 2003–2005. Residency patterns were variable during each year of the study, with younger sandbar sharks spending more time within the array area than older sharks. The number of detections was positively related to the distance of the receiver inshore from the inlet, indicating that young sandbar sharks preferentially utilise protected, shallow near-shore waters. Neonate and juvenile sandbar sharks tended to be detected more frequently within all areas of the inlet at slack tides, during the night and during early dawn hours. Periodogram analyses indicated that juvenile sharks tend to move in the direction of tidal currents. The present study documents large- and small-scale movement patterns of juvenile sandbar sharks and emphasises the importance of nursery-area habitats for this species.

scholarly journals Collection stewardship constrained by resources: The management of religious archives in Pietermaritzburg, KwaZulu-Natal region

2013 ◽  
Vol 34 (1) ◽  
Author(s):  
Francis Garaba
Keyword(s):  
South Africa ◽  
Best Practices ◽  
South African ◽  
African Society ◽  
The South ◽  
South African Society ◽  
Kwazulu Natal ◽  
To Come ◽  
The Voice

A survey using questionnaires, observation and interviews was conducted in 2011 to ascertain the collection stewardship strategies of archival repositories with religious archives in Pietermaritzburg. The study concluded that there was a need to establish a religious archives group in order for the voice of ecclesiastical archives to resonate across South Africa. Through this group, it is hoped that there will be greater coordination and networking amongst the archival repositories. The help of associations such as the South African Society of Archivists, the Oral History Association of South Africa and the South African Preservation Group could greatly assist in fostering best practices in archival management. To champion this worthwhile cause, it would be ideal to come up with an Open Day on religious archives to serve as an advocacy platform. These recommendations are made against a backdrop of the poor state of religious archives in Pietermaritzburg, resulting from acute underfunding and which threatens the survival of this record in the long term.

scholarly journals What can be learned from fishers’ perceptions for fishery management planning? Case study insights from Sainte-Marie, Madagascar

PLoS ONE ◽  
2021 ◽  
Vol 16 (11) ◽  
pp. e0259792
Author(s):  
Thaïs A. Bernos ◽  
Clodio Travouck ◽  
Naly Ramasinoro ◽  
Dylan J. Fraser ◽  
Barbara Mathevon
Keyword(s):  
Fishery Management ◽  
Fishing Effort ◽  
Local Context ◽  
Small Scale ◽  
Factors Influencing ◽  
Ecological Changes ◽  
Local Support ◽  
Management Plans ◽  
The Individual

Local support is critical to the success and longevity of fishery management initiatives. Previous research suggests that how resource users perceive ecological changes, explain them, and cope with them, influences local support. The objectives of this study were two-fold. First, we collated local fishers’ knowledge to characterize the long-term socio-ecological dynamics of the small-scale fishery of Sainte-Marie Island, in Madagascar. Second, we empirically assessed the individual- and site-level factors influencing support for fishery restrictions. Our results indicate that fishers observed a decline in fish abundance and catch sizes, especially in nearshore areas; many also perceived a reduction in fish sizes and the local disappearance of species. To maintain their catches, most fishers adapted by fishing harder and further offshore. Accordingly, fishers identified increased fishing effort (number of fishers and gear evolution) as the main cause of fishery changes. Collectively, our results highlight that the transition from a subsistence to commercial fishery, and resulting changes in the relationship between people and the fisheries, was an underlying driver of fishery changes. Additionally, we found that gender, membership to local associations, coping mechanisms, and perceptions of ecological health, were all interlinked and significantly associated with conservation-oriented attitudes. Conservation-oriented attitudes, however, were not associated with fishers’ willingness to decrease fishing. In the short-term, area-based restrictions could contribute to building support for conservation. In the long-term, addressing the underlying causes of the decline will necessitate collaborations among the various groups involved to progressively build livelihood flexibility. Collectively, our study provides additional insights on the individual- and site-level factors influencing support for fishery restrictions. It also highlights the importance of dialoguing with fishers to ensure that fishery management plans are adapted to the local context.

scholarly journals Movement patterns and growth rate of cavebass Dinoperca petersi (Pisces: Dinopercidae) in the iSimangaliso Marine Protected Area, South Africa

2021 ◽  
Vol 19 (2) ◽  
pp. 45-59
Author(s):  
Bruce Q. Mann ◽  
Gareth L. Jordaan ◽  
Ryan Daly
Keyword(s):  
South Africa ◽  
Growth Rate ◽  
Protected Area ◽  
Marine Protected Area ◽  
Movement Patterns ◽  
Home Range Size ◽  
Average Growth ◽  
Kwazulu Natal ◽  
High Site

Dinoperca petersi is a relatively common fish species caught in the line-fishery in KwaZulu-Natal (KZN), South Africa. Yet, little is known about the biology and ecology of this species. Movement patterns and growth rate of this species were studied based on data obtained from a long-term tag-recapture study conducted in the iSimangaliso Marine Protected Area in northern KZN between 2001-2019. Results showed that D. petersi is a highly resident species with a linear home-range size of 290-405 m. While most fish showed high site fidelity, 8.8 % of the tagged fish showed wider ranging movements of 2.4-90 km. However, only 5 fish showed movements out of no-take zones into adjacent exploited areas, suggesting limited adult spillover. Growth rate of tagged fish was found to be reasonably slow compared to other sympatric predatory reef fish with an average growth rate of 61.76 mm y–1 for smaller fish (gα = 300) and 9.58 mm y–1 for larger fish (gβ = 550). Based on these life history characteristics, options for the future conservation and management of this species are discussed.

Population status of 14 shark species caught in the protective gillnets off KwaZulu - Natal beaches, South Africa, 1978 - 2003

2006 ◽  
Vol 57 (2) ◽  
pp. 225 ◽  
Author(s):  
Sheldon F. J. Dudley ◽  
Colin A. Simpfendorfer
Keyword(s):  
South Africa ◽  
Potential Effect ◽  
Catch Rate ◽  
Population Increase ◽  
Shark Species ◽  
Population Status ◽  
Carcharhinus Leucas ◽  
Kwazulu Natal ◽  
Carcharhinus Obscurus ◽  
Catch Rates

Shark nets have been set off the beaches of KwaZulu–Natal, South Africa, since 1952 to reduce the risk of shark attack. The nets fish in fixed localities 400 m from shore and both directly affect local shark populations and act as fisheries-independent monitoring devices. Reliable catch information at the species level was available for the period 1978–2003. Trends in catch rate and size were used to assess the population status of 14 commonly caught shark species. In addition, a demographic modelling approach was used in conjunction with the catch information to assess the potential effect of the nets on populations. Catch rates of four species (Carcharhinus leucas, C. limbatus, Sphyrna lewini and S. mokarran) showed a significant decline, as did the mean or median length of three species (Carcharhinus amboinensis, C. limbatus and female Carcharodon carcharias). For three species that showed declining catch rates or length the potential effect of the shark nets was assessed to be low, suggesting that other sources of catch were responsible for the declining status. The potential effect of the shark nets was assessed to be high for two species (Carcharhinus obscurus and Carcharias taurus, neither of which showed declines in catch rate or length), because of very low intrinsic rates of population increase.

Unambiguous and Low-Cost Determination of Growth Rates and Ages of Tropical Trees and Palms

Radiocarbon ◽  
2014 ◽  
Vol 56 (1) ◽  
pp. 39-52 ◽  
Author(s):  
Jorge I del Valle ◽  
Juan R Guarín ◽  
Carlos A Sierra
Keyword(s):  
Growth Rates ◽  
Sustainable Forest Management ◽  
Low Cost ◽  
Accurate Determination ◽  
Tropical Trees ◽  
Forest Inventories ◽  
Management Plans ◽  
Cost Determination

The determination of the age of tropical trees and palms is of significant importance for ecological studies and designing sustainable forest management plans. Radiocarbon is a powerful tool that can potentially help the determination of ages and growth rates of these plants. However, the application of 14C analyses has one important problem for trees without annual rings and palms: the calibration of 14C measurements with common programs such as CALIBomb or OxCal gives erroneous determinations for wood formed between AD 1954 and 1964. This problem is illustrated here using samples from a tropical tree (Otoba gracilipes) and a tropical palm (Oenocarpus bataua). This study shows how the use of two adjacent samples can help to unambiguously determine the real age of the samples and their mean growth rates. For comparison, long-term growth measurements for both species were used and it was determined that 14C analyses provide accurate determination of growth rates for tropical trees and palms. Furthermore, the application of 14C analyses in palms allows the determination of the rosette stage, rarely quantified in forest inventories and life-history studies.

Occurrence, home range and movement patterns of juvenile bull (Carcharhinus leucas) and lemon (Negaprion brevirostris) sharks within a Florida estuary

2008 ◽  
Vol 59 (6) ◽  
pp. 489 ◽  
Author(s):  
B. G. Yeiser ◽  
M. R. Heupel ◽  
C. A. Simpfendorfer
Keyword(s):  
Home Range ◽  
Coastal Lagoons ◽  
Movement Patterns ◽  
Shark Species ◽  
Convex Polygons ◽  
Negaprion Brevirostris ◽  
Large Juvenile ◽  
Carcharhinus Leucas ◽  
Coastal Species

The movement patterns of large juveniles are poorly known for many shark species. With increasing pressure on shark populations these data are critical for the management of large coastal species. A series of acoustic receivers were positioned in Pine Island Sound, Florida, USA, to passively track the long-term movements of large juvenile bull (Carcharhinus leucas) and lemon (Negaprion brevirostris) sharks. Nineteen C. leucas and five N. brevirostris were monitored during 2003 and 2004. Individual C. leucas were present for 8 to 89 days, while N. brevirostris were present for 12 to 83 days. Weekly minimum convex polygons and kernel utilisation distributions were calculated to demonstrate the home range and core areas of use of both species. Spectral analysis demonstrated that several N. brevirostris showed repetitive diel north–south movement patterns over periods of up to 28 consecutive days. C. leucas demonstrated regular use of backwater habitats. Long-term use of estuarine areas by these large juvenile sharks suggests that estuarine coastal lagoons provide an important habitat for this portion of their life history and as such, protection of these habitats may assist in shark management and conservation.

Stochastic Investment Modelling: The Case of South Africa

1996 ◽  
Vol 2 (3) ◽  
pp. 765-801 ◽  
Author(s):  
R.J. Thomson
Keyword(s):  
South Africa ◽  
Time Series ◽  
Interest Rates ◽  
South African ◽  
Growth Rates ◽  
Time Series Models ◽  
Short Term ◽  
Model Based ◽  
Inflation Rates

ABSTRACTThe purpose of this paper is to describe a methodology for determining an appropriate structure for time-series models of inflation rates, short-term and long-term interest rates, dividend growth rates, dividend yields, rental growth rates and rental yields and to demonstrate the application of that methodology to the development of a model based on South African data. It is suggested that the methodology used in this paper may be applied to other economic environments.

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