Potential of a trap-fishery for deep-water rock lobster Palinurus delagoae off South Africa

1997 ◽  
Vol 48 (8) ◽  
pp. 993 ◽  
Author(s):  
J. C. Groeneveld ◽  
A. C. Cockcroft
Keyword(s):  
South Africa ◽  
South African ◽  
Deep Water ◽  
Linear Models ◽  
Depth Interval ◽  
Suitable Habitat ◽  
Rock Lobster ◽  
Experimental Phase ◽  
Trap Fishery ◽  
Catch Rates

An experiment to investigate the potential of a trap-fishery for deep-water rock lobster Palinurus delagoae was conducted off the east coast of South Africa between 1994 and 1996. The 75–425 m depth interval between 27°S and 32°S was stratified according to depth and latitude, and three regions (North, Central and South) were sampled systematically over the three years. Sampling by commercial vessels operating long-lines and traps included an experimental phase (fixed fishing positions) and a commercial phase (no restriction on fishing location). Generalized linear models were used to investigate the influence of year, region, sampling phase, month and soak time. Sampling phase was significant, with traps set during the commercial phase catching more than those set in the experimental phase. The effect of soak time on catch rates was not significant. The almost-50% decrease in the combined abundance index combined with a marked decrease in mean lobster size over the study period suggests a relatively low fisheries potential for this species in South African waters; this may be attributable to the relative scarcity of suitable habitat in the area.

Fishery for the deep-water spiny lobster Palinurus delagoae in Mozambique, 1980 to 1999

2001 ◽  
Vol 52 (8) ◽  
pp. 1535 ◽  
Author(s):  
Barbara Palha de Sousa
Keyword(s):  
Shallow Water ◽  
Deep Water ◽  
Linear Models ◽  
Spiny Lobster ◽  
Catch Rate ◽  
Rapid Decline ◽  
Adult Size ◽  
Size Category ◽  
Trap Fishery ◽  
Catch Rates

Catch and effort data collected from 1980 to 1999 from the commercial trap fishery for Palinurus delagoae off Mozambique are presented.Generalized linear models, using the variables year, month, area, and depth, indicate a marked decline in catch rate with time.Intensive exploitation has led to a rapid decline in catches (102 to 48 tonnes) and catch rates (0.74 to 0.33 kg/trap haul) during the last five years. This decline indicates that the population is sensitive to the high fishing levels (over 200000 trap hauls), particularly since 1993. As these lobsters are generally slow growing and long lived, recovery is expected to take a number of years, provided that fishing stays relatively low. Studies of different size categories show that juvenile catch rate was highest in deep water and during summer after the moult in August to October, whereas the larger adult size category was caught more in shallow water during spring, probably during the mating aggregation. These catch rates reflect an inshore migration of juveniles from deep to shallow water. The decline in catch rate appeared greater amongst the small (juvenile) and medium lobsters because these more abundant categories are more often the target of the fishery.

scholarly journals Abundance indices for long-lived tropical snappers: estimating standardized catch rates from spatially and temporally coarse logbook data

2013 ◽  
Vol 71 (3) ◽  
pp. 618-627 ◽  
Author(s):  
Ross J. Marriott ◽  
Michael F. O'Neill ◽  
Stephen J. Newman ◽  
Craig L. Skepper
Keyword(s):  
Linear Models ◽  
Fish Population ◽  
Large Area ◽  
Daily Data ◽  
Trap Fishery ◽  
Annual Time Series ◽  
Spatio Temporal ◽  
Age Structured ◽  
Catch Rates ◽  
Annual Time

Abstract The Northern Demersal Scalefish Fishery has historically comprised a small fleet (≤10 vessels year−1) operating over a relatively large area off the northwest coast of Australia. This multispecies fishery primarily harvests two species of snapper: goldband snapper, Pristipomoides multidens and red emperor, Lutjanus sebae. A key input to age-structured assessments of these stocks has been the annual time-series of the catch rate. We used an approach that combined Generalized Linear Models, spatio-temporal imputation, and computer-intensive methods to standardize the fishery catch rates and report uncertainty in the indices. These analyses, which represent one of the first attempts to standardize fish trap catch rates, were also augmented to gain additional insights into the effects of targeting, historical effort creep, and spatio-temporal resolution of catch and effort data on trap fishery dynamics. Results from monthly reported catches (i.e. 1993 on) were compared with those reported daily from more recently (i.e. 2008 on) enhanced catch and effort logbooks. Model effects of catches of one species on the catch rates of another became more conspicuous when the daily data were analysed and produced estimates with greater precision. The rate of putative effort creep estimated for standardized catch rates was much lower than estimated for nominal catch rates. These results therefore demonstrate how important additional insights into fishery and fish population dynamics can be elucidated from such “pre-assessment” analyses.

scholarly journals Making management procedures operational—innovations implemented in South Africa

2007 ◽  
Vol 64 (4) ◽  
pp. 626-632 ◽  
Author(s):  
Éva E. Plagányi ◽  
Rebecca A. Rademeyer ◽  
Doug S. Butterworth ◽  
Carryn L. Cunningham ◽  
Susan J. Johnston
Keyword(s):  
South Africa ◽  
South African ◽  
Ecosystem Approach ◽  
Management Tool ◽  
Rock Lobster ◽  
Single Model ◽  
Short Term ◽  
The Past ◽  
Management Procedures ◽  
Operational Management

Abstract Plagányi, É. E., Rademeyer, R. A., Butterworth, D. S., Cunningham, C. L., and Johnston, S. J. 2007. Making management procedures operational — innovations implemented in South Africa. – ICES Journal of Marine Science, 64: 626–632. Operational management procedures (OMPs) have become an indispensable fisheries management tool in South Africa in light of their ability to consider the consequences of the main sources of assessment uncertainty. An overview is provided of the MP approaches applied to the major South African fisheries for hake, sardine and anchovy, and west coast rock lobster. As these are among the first OMPs to be implemented worldwide, some for periods longer than 10 y, they provide useful examples of some of the successes and problems encountered with the approach. Particular emphasis is given to some recent innovations and adaptations. These include moves to (i) joint two-species OMPs for the hake and sardine/anchovy resources; (ii) a reference set of weighted operating models for primary testing and tuning in preference to a single model; (iii) consideration of a “research-conditional” approach for hake to allow greater catches in the short term, conditional on research being implemented to resolve a key uncertainty; and (iv) incorporation of some ecosystem considerations by developing appropriate robustness tests (which link with moves towards an ecosystem approach to fisheries). Key lessons gained from experience over the past decade of OMP implementation in South Africa are summarized.

Combining field phenological observations with distribution data to model the potential distribution of the fruit fly Ceratitis rosa Karsch (Diptera: Tephritidae)

2012 ◽  
Vol 103 (1) ◽  
pp. 60-73 ◽  
Author(s):  
M. de Villiers ◽  
V. Hattingh ◽  
D.J. Kriticos
Keyword(s):  
South Africa ◽  
South African ◽  
Relative Abundance ◽  
Potential Distribution ◽  
Fruit Fly ◽  
Global Distribution ◽  
Biological Information ◽  
Distribution Data ◽  
Suitable Habitat ◽  
Independent Distribution

AbstractDespite the potential for phenological and abundance data to improve the reliability of species niche models, they are seldom used. The aim of this study was to combine information on the distribution, relative abundance and seasonal phenology of Natal fruit fly, Ceratitis rosa Karsch (Diptera: Tephritidae), in South Africa to model its potential global distribution. Bucket traps, baited with Biolure, were used to trap C. rosa in different climatic regions of South Africa over a two-year period. A CLIMEX niche model of the potential global distribution of C. rosa was fitted using the collected trapping data and other distribution records from South Africa. Independent distribution records for elsewhere in Africa were reserved for model validation. The CLIMEX model results conformed well to the South African trapping data, including information on relative abundance and seasonal phenology, as well as to the pattern of presence records of the species elsewhere in Africa. The model suggests that under recent historical conditions a large part of South America, Central America, Mexico and southern USA may be climatically suitable for establishment of C. rosa. In Europe, climatically suitable habitat is restricted to coastal regions of the Mediterranean, in Asia, mostly to the southern and south eastern countries, and in Australia mostly to the wetter south and east. The independent cross-validation provided by South African relative abundance and seasonal phenology data, central African distribution data and relevant species specific biological information provides greater confidence in the modelled potential distribution of C. rosa.

Review of the Fishery for and Biology of the Cape Rock Lobster Jasus lalandii with Notes on Larval Recruitment

1986 ◽  
Vol 43 (11) ◽  
pp. 2107-2117 ◽  
Author(s):  
David E. Pollock
Keyword(s):  
South African ◽  
Size Range ◽  
Fishing Mortality ◽  
Age At Maturity ◽  
Rock Lobster ◽  
Larval Recruitment ◽  
Stock Recruitment ◽  
Larval Production ◽  
Catch Rates ◽  
High Level

The South African fishery for the rock lobster Jasus lalandii currently yields about 3800 metric tons (8.4 million animals) of which more than 90% are males. Males grow much faster than females, and a size limit which is fairly large in relation to the size and age at maturity protects females from exploitation for most of their lifespans, thereby ensuring a high level of larval production from the population. Exploitation rates in the fishery are controlled by means of quotas on fishing companies, as well as catch limits on individual fishing grounds. Quotas are reassessed annually to maintain instantaneous fishing mortality rates of approximately 0.3 on all grounds. Catch rates on most grounds have been increasing since area catch limits were introduced in 1980, and seasonal averages now vary between 4 and 12 kg∙trap-day−1. Although annual indices of puerulus larval recruitment are not available, and the stock–recruitment relationship is unknown, it appears that relatively stable yields can be maintained despite fluctuations in puerulus recruitment. Density-dependent regulatory mechanisms operative in juvenile and young adult stages tend to dampen large variations in the numbers of adults entering the fishable size range each year. Variations in puerulus recruitment are likely to result from changes in the paths and velocities of extensive offshore currents which eventually return larvae toward the coast of South Africa after many months of pelagic existence.

Reframing Xenophobia in South Africa as Colour-Blind: The Limits of the Afro Phobia Thesis

2020 ◽  
Vol 17 (3) ◽  
pp. 433-444
Author(s):  
Amanuel Isak Tewolde
Keyword(s):  
South Africa ◽  
South African ◽  
Analytical Framework ◽  
Conflict Theory ◽  
Black African ◽  
South Africans ◽  
Theoretical Perspectives ◽  
Online Newspaper ◽  
Close Proximity ◽  
Realistic Conflict Theory

Many scholars and South African politicians characterize the widespread anti-foreigner sentiment and violence in South Africa as dislike against migrants and refugees of African origin which they named ‘Afro-phobia’. Drawing on online newspaper reports and academic sources, this paper rejects the Afro-phobia thesis and argues that other non-African migrants such as Asians (Pakistanis, Indians, Bangladeshis and Chinese) are also on the receiving end of xenophobia in post-apartheid South Africa. I contend that any ‘outsider’ (White, Asian or Black African) who lives and trades in South African townships and informal settlements is scapegoated and attacked. I term this phenomenon ‘colour-blind xenophobia’. By proposing this analytical framework and integrating two theoretical perspectives — proximity-based ‘Realistic Conflict Theory (RCT)’ and Neocosmos’ exclusivist citizenship model — I contend that xenophobia in South Africa targets those who are in close proximity to disadvantaged Black South Africans and who are deemed outsiders (e.g., Asian, African even White residents and traders) and reject arguments that describe xenophobia in South Africa as targeting Black African refugees and migrants.

Region of Birth and Child Mortality among Black Migrants to South Africa: Is there a foreign-born advantage?

2016 ◽  
Vol 13 (3) ◽  
pp. 359-376 ◽  
Author(s):  
Tiffany L Green ◽  
Amos C Peters
Keyword(s):  
South Africa ◽  
South African ◽  
Child Mortality ◽  
Southern Africa ◽  
Strong Relationship ◽  
Developed Countries ◽  
Black Immigrants ◽  
Foreign Born ◽  
Region Of Origin ◽  
Child Deaths

Much of the existing evidence for the healthy immigrant advantage comes from developed countries. We investigate whether an immigrant health advantage exists in South Africa, an important emerging economy.  Using the 2001 South African Census, this study examines differences in child mortality between native-born South African and immigrant blacks.  We find that accounting for region of origin is critical: immigrants from southern Africa are more likely to experience higher lifetime child mortality compared to the native-born population.  Further, immigrants from outside of southern Africa are less likely than both groups to experience child deaths.  Finally, in contrast to patterns observed in developed countries, we detect a strong relationship between schooling and child mortality among black immigrants.

Some Reflections on Reparation in Post-Apartheid South Africa, using a Couple Therapy Intervention as a Microcosm of South African Society

2011 ◽  
Vol 1 (2) ◽  
Author(s):  
Andrea Hill ◽  
Sylvia Poss
Keyword(s):  
South Africa ◽  
South African ◽  
Couple Therapy ◽  
South African Society ◽  
Depressive Position ◽  
Central Hypothesis ◽  
Transference And Countertransference ◽  
Constructive Engagement ◽  
The Impact ◽  
Therapy Intervention

The paper addresses the question of reparation in post-apartheid South Africa. The central hypothesis of the paper is that in South Africa current traumas or losses, such as the 2008 xenophobic attacks, may activate a ‘shared unconscious phantasy’ of irreparable damage inflicted by apartheid on the collective psyche of the South African nation which could block constructive engagement and healing. A brief couple therapy intervention by a white therapist with a black couple is used as a ‘microcosm’ to explore this question. The impact of an extreme current loss, when earlier losses have been sustained, is explored. Additionally, the impact of racial difference on the transference and countertransference between the therapist and the couple is explored to illustrate factors complicating the productive grieving and working through of the depressive position towards reparation.

The Final ‘Thank You’

Derrida Today ◽  
2010 ◽  
Vol 3 (1) ◽  
pp. 21-36
Author(s):  
Grant Farred
Keyword(s):  
South Africa ◽  
South African ◽  
Jacques Derrida ◽  
Political Transition ◽  
The Other ◽  
World Cup ◽  
The Core ◽  
Nelson Mandela ◽  
Black President ◽  
The Moment

‘The Final “Thank You”’ uses the work of Jacques Derrida and Friedrich Nietzsche to think the occasion of the 1995 rugby World Cup, hosted by the newly democratic South Africa. This paper deploys Nietzsche's Zarathustra to critique how a figure such as Nelson Mandela is understood as a ‘Superman’ or an ‘Overhuman’ in the moment of political transition. The philosophical focus of the paper, however, turns on the ‘thank yous’ exchanged by the white South African rugby captain, François Pienaar, and the black president at the event of the Springbok victory. It is the value, and the proximity and negation, of the ‘thank yous’ – the relation of one to the other – that constitutes the core of the article. 1

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