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1
McCafferty, James Ross. "An assessment of inland fisheries in South Africa using fisheries-dependent and fisheries-independent data sources." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1005072.
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The role of inland fisheries as contributors to local and national economies in developing African countries is well documented. In South Africa, there is increasing interest in inland fisheries as vehicles for achieving national policy objectives including food security, livelihoods provision, poverty alleviation and economic development but there is surprisingly little literature on the history, current status, and potential of inland fishery resources. This lack of knowledge constrains the development of management strategies for ensuring the biological sustainability of these resources and the economic and social sustainability of the people that are dependent on them. In order to contribute to the knowledge base of inland fisheries in South Africa this thesis: (1) presents an exhaustive review of the available literature on inland fisheries in South Africa; (2) describes the organisation of recreational anglers (the primary users of the resource); (3) compiles recreational angling catch records and scientific gill net survey data, and assesses the applicability of these data for providing estimates of fish abundance (catch-per-unit effort [CPUE]); and finally, (4) determines the potential for models of fish abundance using morphometric, edaphic, and climatic factors. The literature review highlighted the data-poor nature of South African inland fisheries. In particular information on harvest rates was lacking. A lack of knowledge regarding different inland fishery sectors, governance systems, and potential user conflicts was also found. Recreational anglers were identified as the dominant user group and catch data from this sector were identified as potential sources of fish abundance and harvest information. Formal freshwater recreational angling in South Africa is a highly organised, multi-faceted activity which is based primarily on angling for non-native species, particularly common carp Cyprinus carpio and largemouth bass Micropterus salmoides. Bank anglers constituted the largest number of formal participants (5 309 anglers affiliated to formal angling organisations) followed by bass anglers (1 184 anglers affiliated to formal angling organisations). The highly structured nature of organised recreational angling and dominant utilisation of inland fisheries resources by this sector illustrated not only the vested interest of anglers in the management and development of inland fisheries but also the role that anglers may play in future decision-making and monitoring through the dissemination of catch data from organised angling events. Generalised linear models (GLMs) and generalised additive models (GAMs) were used to standardise CPUE estimates from bass- and bank angling catch records, which provided the most suitable data, and to determine environmental variables which most influenced capture probabilities and CPUE. Capture probabilities and CPUE for bass were influenced primarily by altitude and conductivity and multiple regression analysis revealed that predictive models incorporating altitude, conductivity, surface area and capacity explained significant (p<0.05) amounts of variability in CPUE (53%), probability of capture (49%) and probability of limit bag (74%). Bank angling CPUE was influenced by conductivity, surface area and rainfall although an insignificant (p>0.05) amount of variability (63%) was explained by a predictive model incorporating these variables as investigations were constrained by small sample sizes and aggregated catch information. Scientific survey data provided multi-species information and highlighted the high proportion of non-native fish species in Eastern Cape impoundments. Gillnet catches were influenced primarily by species composition and were less subject to fluctuations induced by environmental factors. Overall standardised gillnet CPUE was influenced by surface area, conductivity and age of impoundment. Although the model fit was not significant at the p<0.05 level, 23% of the variability in the data was explained by a predictive model incorporating these variables. The presence of species which could be effectively targeted by gillnets was hypothesised to represent the most important factor influencing catch rates. Investigation of factors influencing CPUE in impoundments dominated by Clarias gariepinus and native cyprinids indicated that warmer, younger impoundments and smaller, colder impoundments produced higher catches of C. gariepinus and native cyprinids respectively. A predictive model for C. gariepinus abundance explained a significant amount of variability (77%) in CPUE although the small sample size of impoundments suggests that predictions from this model may not be robust. CPUE of native cyprinids was influenced primarily by the presence of Labeo umbratus and constrained by small sample size of impoundments and the model did not adequately explain the variability in the data (r² = 0.31, p>0.05). These results indicate that angling catch- and scientific survey data can be useful in providing predictions of fish abundance that are biologically realistic. However, more data over a greater spatial scale would allow for more robust predictions of catch rates. This could be achieved through increased monitoring of existing resource users, the creation of a centralised database for catch records from angling competitions, and increased scientific surveys of South African impoundments conducted by a dedicated governmental function.
2
Mbane, Nontuthuzelo Nosisa. "The South African marine fisheries policy since 1994." Thesis, Cape Technikon, 2004. http://hdl.handle.net/20.500.11838/1664.
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Dissertation (MTech( Public Management))--Cape Technikon, Cape Town, 2004Marine resources play a major role in sustaining the economy and social development of the nation and contribute to national economy, to employment and security of the local community. The South African fisheries management was conducted largel)' with political default. This denied most fishers access to marine resources. Since the democratic election of 1994, the government was left with the challenge to re-allocate rights in a way that would ensure that the under-presentation of historical disadvantaged individuals (HDl's) in the fishing industry would be corrected. The laws and regulations related to marine fisheries were also revised. The Marine Living Resources Act, No. 18 of 1998 attempted transformation in the fishing industry but lacked clear guidelines which led to litigation and crises in the fishing industry as many fishers were unhappy with the whole process. Marine fisheries policy was established and published in 1997 to address those historical imbalances by introducing the fishing right system of allocating rights to represent the national demographics of the country. This report seeks to describe the theory of the South African fishing industry, policy developments and the current status of permit allocation in South Africa. It will also examine the effectiveness in the implementation of the marine fisheries policy for South Africa. It will focus on the distribution of marine resources for commercial fishing purposes.
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Hutton, Trevor Patrick. "Fisheries management policy in South Africa : an evaluation of alternative management strategies for the Hake and Linefish fisheries." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape2/PQDD_0020/NQ56561.pdf.
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Mather, Diarmid John. "Fishing rights, redistribution and policy : the South African commercial T.A.C. fisheries." Thesis, Rhodes University, 2005. http://hdl.handle.net/10962/d1007531.
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The main objective of this thesis is to provide an analysis of the economic logic behind fisheries policy and redistribution in South African. An examination of the institutional and organizational evolution reveals that South African fisheries policy followed the world trend in the movement toward quota management systems. However, it is argued that due to the peculiarities of the Apartheid political system, South Africa developed a unique and persistent structure of individual fishing rights that resulted in a transfer of power from the fisher to monopsonistic, and subsequently vertically integrated, fish processing companies. Problems, however, arose with the need to redistribute fishing rights to previously repressed racial groups. It is proposed that, within a specific form (TAC), the structure of individual fishing rights can be decomposed into four operational rules, namely, the right of participation, asset size, tradability and duration of term. Policy design is restricted to a feasible set of rules that impact on the flexibility of the system, the incentives facing private fishing companies and fishers, the efficiency of the fisheries management plan and finally the effect it has on a redistribution strategy. Within this analytical framework, South Africa's policy yields a very flexible system favourable to monopsonistic industrial organisation. However, by adding a redistribution constraint, this structure has a number of important effects. First, as new quota holders are added the information costs for effective fisheries management increase exponentially. Second, the transaction costs to private fishing companies are increased. Third, only the resource rent is redistributed (weak redistribution). Next, the micro to small vessel fisheries, the medium vessel fisheries and the large vessel fisheries are examined separately. The major aim is to determine, within the available data, the effect that a weak redistribution policy (redistribution of the resource rent), has on strong redistribution (redistribution of fishing capital and skills). The evidence definitely supports the analytical framework and suggests that fundamentally the structure of individual fishing rights, which evolved in response to a monopsonistic industrial organisation during the apartheid era in South Africa, works against strong redistribution. Also, that different fisheries face different constraints and that these should in certain instances be treated separately.
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Ngqongwa, Abongile. "Small-scale fisheries governance in South Africa using information management systems." Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/15586.
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Conventional management approaches, focused primarily on stock status and top-down driven regulatory measures, such as are employed in many commercial fisheries across the globe, have proven to be inadequate in managing small-scale fisheries and have contributed to marginalisation of this sector. In South Africa, small-scale fisheries have been increasingly recognised since the abolishment of Apartheid and the advent of democracy in 1994. Nevertheless, the management approaches implemented have been largely top-down, natural science-driven and single-species approach. South Africa's fishery sector is currently going through a historic moment where all small-scale fishers are awaiting implementation of a new Small-Scale Fisheries Policy that will see it endorsing the holistic, multi-species and people-centred approach and the recognition of local and indigenous knowledge of fisheries and addressing the complex socio-economic needs of the fishers. However, in order to implement this policy using a co-management and EAF approach, Government and fishing communities will need to set up the required information-gathering and monitoring tool that would be in line with the principles and objectives of the South African Small-Scale Fisheries Policy as careful assessment of social and economic outcomes of fisheries policies is required to support and sustain livelihoods of these fishers. A proper information management system (IMS) would further ensure that the new approaches to small-scale fisheries management are practical and effective in managing this sector. In investigating the small-scale fisheries information management system, the researcher conceptualised and designed an IMS and further conducted case studies by analysing and work-shopping results of analysed catch data recorded by an independent service provider to Doringbaai small-scale fishers, and analysed catch data of East Coast Rock Lobster in the Eastern Cape of South Africa. Based on the results of the conceptualised and designed IMS and that of the analysed catch data, it is clear that there is a need for the IMS to be converted into a web-based system and further accommodate more indicators that would assist in equipping fishers and fisheries authorities with relevant decision-making. It is also clear that there is a need for an urgent overhaul in how catch data is gathered and packaged as there were numerous errors in the data that could affect how small-scale fisheries should be managed. One of the interventions urgently needed is implementation of an electronic data capturing and instant synchronisation of data into the IMS which would present live data through a web interface customised per user type. Such tool would improve the current management measures and further contribute to improving governance of small-scale fisheries when the Small-Scale Fisheries Policy is implemented.
6
Brouwer, Stephen Leonard. "An assessment of the South African east coast linefishery from Kei Mouth to Stil Bay." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1005076.
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During the period April 1994 and February 1996 as part of an investigation into the national Iinefishery, the east coast shore fishery and the recreational and commercial ski-boat fisheries were surveyed, at eight sites between Kei Mouth in the East and Stil Bay in the West. Roving creel, access point and aerial surveys were used. A questionnaire was developed for each sector to gather data on catch and effort, fisher demographics, economics, fisher attitudes towards, and knowledge of, the current management regulations and assess the efficacy of the fisheries inspectorate. During the access point survey the catch of 3273 fishers was inspected and 1556 interviews were conducted. Questionnaires were conducted on 118 recreational ski-boaters and the catch of 165 boats was inspected. 96 commercial skippers were interviewed and 230 had their catch inspected. Three aerial surveys of the entire area were conducted during which a total of 1067 shore fishers were counted giving a shore fisher density of 0.39 fishers.km⁻¹. The majority (99%) of participants in all sectors of the linefishery were male. The greatest number of participants were white, shore fishery 77% recreational ski-boat 98% commercial skiboat 89%, followed by coloured, asian and black people. To a large extent this reflects the income of various racial groups. Most fishers supported the current linefish management plan. However, when tested on their knowledge of the size limits, bag limits and closed seasons of their target species many shore fishers (59%) did not know them and a high proportion of fishers in all sectors had disobeyed at least one of the regulations (shore 50%, recreational ski-boat 70%, commercial ski-boat 56%). When compared to historical data the present catch per unit effort (CPUE) in all sectors has decreased. Most interviewees in the various sectors did not accept responsibility for the decline in CPUE, but attributed it to three principal reasons vis their perceived direct competitors, trawling and pollution. Analysis of the catch revealed that all sectors were multispecies fisheries, with each sector being characterised by a small number of target species. Catch composition differed significantly between the shore and ski-boat sectors, but there was significant overlap between the two skiboat sectors. Analysis of the catch in comparison to that reported to the National Marine Linefish System (NMLS) revealed that there was a substantial degree of under-reporting. There was little seasonal difference in effort in the shore fishery while the recreational ski-boat effort was highest in the summer and the commercial ski-boat effort was high in the winter. Effort in the shore and recreational ski-boat fisheries was concentrated over weekends while the commercial ski-boat effort was highest during weekdays. Total effort for the entire area was estimated at 903 186 (±1913) fisher days per annum in the shore fishery, 24 357 (±685) recreational ski-boat fisher days and 64 266 (±1686) commercial ski-boat fisher days. Expenditure and capital investment in the various sectors was calculated, as were earnings of the participants in the commercial ski-boat sector. The linefishery in the Eastern Cape was estimated to have a minimum capital investment in excess of R210 million and more than R32 million is spent annually on running costs. The commercial ski-boat fishery directly employed an estimated 3184 people. The economic implications of changes in CPUE for the commercial ski-boat fishery are considered, as are the benefits of a recreational angling licence. Management of the linefishery is discussed in relation to the findings of this study.
7
Japp, David William. "An assessment of the South African longline fishery with emphasis on stock integrity of kingklip, Genypterus capensis (Pisces : ophidiidae)." Thesis, Rhodes University, 1989. http://hdl.handle.net/10962/d1004660.
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The South African demersal longline experiment is assessed with emphasis on the target species, kingklip Genypterus capensis. The hypothesis that kingklip on the South African coast comprise a unit stock is tested. Recommendations for the management of the fishery are made. Longlining was found to be commercially viable. Techniques have been developed to target on either kingklip or the Cape hakes, Herluccius capensis and H. paradoxus. Longline fishermen exploit the kingklip spawner stock from August to No v ember by taking advantage of prespawning aggregations on the South-East Coast . Effort switches to the West Coast in late summer and early winter where kingklip are less abundant and a larger proportion of hake is caught. Catch rates of kingklip on the South Coast have declined sharply and the resource there has been exploited at a rate greater than that required to retain 50% of the unexploited biomass . There is a 17,6% probability that the spawner biomass on the South Coast has already been depleted below its pristine level. On the West Coast the catch rates of kingklip are lower than on the South Coast and have not changed significantly, although within the 95% confidence limits there is a possibility that the resource there has also been depleted below 50% of its pristine level. Genypterus capensis on the South African coast comprise a unit stock. Comparison of kingklip morphology using multivariate and discriminant function analysis and of otolith morphology using univariate statistics shows that there are no significant differences between the fish on the West and South Coasts. They are a slow growing species and were aged up to 25 years. Kingklip on the West Coast are smaller and have a lower L~ than those on the South Coast, but this is not a characteristic of discrete stocks. Kingklip on the South Coast mature earlier than those on the West Coast and aggregate to spawn on the South - East Coast in spring. There is no obvious spawning period on the West Coast. It is hypothesized that kingklip spawning on the South-East Coast is in response to favourable environmental conditions that enhances the survival of their eggs and larvae. It is recommended that demersal longlining be established as a permanent kingklip-directed fishery but that effort should not be allowed to increase. The West and South Coasts should be managed .separately. A TAC of 5 OOOt for kingklip should be introduced for 1989 of which 2 OOOt should be allocated to the West Coast and 3 OOOt to the South Coast . A closed season for kingklip from 1 August to 30 September on the South-East Coast is recommended. Hake-directed longlining should not be allowed as its effect on the hake spawner stocks are unknown and could be a potential threat to the stability of the demersal trawl fishery.
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Schön, Pieter-Jan. "An investigation into the influence of the environment on spawning aggregations and jig catches of chokka squid Loligo Vulgaris reynaudii off the south coast of South Africa." Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1016369.
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Erratic and highly variable catches in the South African chokka squid Loligo vulgaris reynaudii fishery, cause socio-economic hardship for the industry and uncertainty for resource managers. Catch forecasting can reduce this problem as it is believed that catch variability is strongly influenced by environmental factors. In this study, data were collected at varying temporal and spatial scales. Data for the hourly time-scale study were collected from 1996-1998, aboard commercial vessels, whilst for the longer time-scales, data were extracted for Kromme Bay (a single fishing area) from existing databases (1991-1998) that were comprised of compulsory catch returns and oceanographic data. The environment-catch relationship for chokka squid on the inshore spawning grounds was then investigated using multiple correlation and regression analysis, analysis of variance, contingency table analysis and cross-correlation statistical techniques. This simple, direct, 'black box' statistical approach was relatively successful in developing a predictive capability. On a short time-scale (hourly), the regression model accounted for 32% of the variability in catch, with turbidity the main determinant (13%). On a daily monthly time-scale, the best prediction model was on a monthly scale, accounting for 40% of the variability in catch. The principal determinant, bottom temperature anomaly (11 %), was found to lag one month forward. Seasonal and diel catch variations induced changes in the relative importance of turbidity, water temperature and wind direction on catches. A strong, positive relationship was found between easterly winds (which cause upwelling) and catch, particularly in summer. Catch rates, however, decreased with an increase in turbidity. The correlation between temperature and catch was generally negative, however, higher catches were associated with a temperature range of 13-18°C. Highest catch rates were associated with easterly winds, zero turbidity conditions and sea surface temperatures from 15.0-16.9°C. Selected case studies (in situ observations) suggested that upwelling and turbidity events act as environmental triggers for the initiation or termination of the spawning process, respectively. A holistic approach is required to improve predictive capability of chokka squid abundance. Although short-term predictability remains essential (i.e. hourly-scale), future research should concentrate on long-term prediction models (e.g., monthly time-scales) involving greater spatial variation, which are the most important for management.
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Walmsley, Sarah Ann. "The assessment and management of bycatch and discards in the South African demersal trawl fishery." Thesis, Rhodes University, 2005. http://hdl.handle.net/10962/d1005071.
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Over the past few decades it has become recognised that an ecosystem approach is required to manage world fisheries. Management strategies must ensure that non-target (bycatch) as well as target catches are sustainable. To achieve this, detailed commercial catch and biological information is required. The composition of catches made by trawlers operating off the south and west coasts of South Africa was investigated. Distinct fishing areas were identified on each coast, based on target species and fishing depth. Catch composition differed markedly among the areas defined. Although hake Merluccius sp. dominated South Coast catches, a large proportion of the catch was composed of bycatch. On the West Coast, hake dominated catches and this domination increased with increasing depth. On both coasts approximately 90% of the observed nominal catch was processed and landed. Estimates of annual discards suggested that the fishery discarded 38 thousand tons of fish per annum (16% of the nominal trawl catch). The data also indicated that hake discarding, the capture of linefish and the increased targeting of high value species might be cause for concern. Spatial analysis indicated that a variety of factors such as trawling position, catch size and catch composition affects bycatch dynamics. The monkfish Lophius vomerinus is a common bycatch species that has been increasingly targeted by demersal trawlers. This study showed that L. vomerinus is a slow-growing, long-lived species (West Coast males L∞ = 68.50cm TL, t₀ = -1.69yr, K = 0.10yr⁻¹; West Coast females L∞ = 110.23cm TL, t₀ = -1.54yr, K = 0.05yr⁻¹; South Coast sexes combined L∞ = 70.12cm TL, t₀ = - 0.80yr, K = 0.11yr⁻¹), that matures at approximately 6 years of age. These traits could have serious management implications for the species. Per-recruit analysis suggested that the stock might be overexploited, although further investigation is required to confirm this. Solutions were suggested for each of the concerns raised, taking cognisance of the differences observed between the South and West Coasts and the economic dependence of South Coast companies on bycatch. The needs of future research were considered.
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Martin, Lindsay. "Fisheries management, fishing rights and redistribution within the commercial chokka squid fishery of South Africa." Thesis, Rhodes University, 2005. http://hdl.handle.net/10962/d1007500.
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The objective of this thesis is to analyse the management and redistribution policies implemented in the South African squid industry. This is done within the broader context of fisheries policies that have been implemented within the South African fishing industry as the squid industry has developed. The study therefore has an institutional basis, which reviews the development of institutional mechanisms as they have evolved to deal fisheries management problems. These mechanisms (which can either be formal or informal) consist of committees, laws and constitutions that have developed as society has progressed. Probably the most prominent of these, in terms of current fisheries policy, is the Marine Living Resources Act (MLRA) of 1998. The broad policy prescription of the MLRA basically advocates the sustainable utilisation of marine resources while outlining the need to restructure the fishing industry to address historical imbalances and to achieve equity. It is this broad objective that this thesis applies to the squid fishery. The primary means of achieving the above objective, within the squid industry, has been through the reallocation of permit rights. These rights also provide the primary means by which effort is managed. A disruption in the rights allocation process therefore has implications for resource management as well. Permits rights can be described as a form of use right or propertY right. These rights are structured according to their operational-level characteristics, or rules. Changing these rules can thus affect the efficiency or flexibility of a rights based system. This is important because initial reallocation of rights, by the Department of Environmental Affairs and Tourism (DEAT), was based on an incomplete set of rights. This partly led to the failure of early redistribution attempts resulting in a "paper permit" market. Nevertheless, this thesis argues that redistribution attempts were based on ill-defined criteria that contributed to the failure described above. In addition to this the method through which redistribution was attempted is also questionable. This can be described as a weak redistribution strategy that did not account for all equity criteria (i.e. factors like capital ownership, employment or relative income levels). This thesis thus recommends, among other things, that an incentive based rights system be adopted and that the design of this system correctly caters of the operational-level rules mentioned above. In addition to this a strong redistribution, based on fishing capital, ownership, income and the transfer of skills, should be implemented.KMBT_363
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Maree, R. C. "Environmental influences on the daytime vertical distribution of Cape hakes and implications for demersal trawl estimates of hake abundance off the west coast of South Africa." Thesis, Rhodes University, 2000. http://hdl.handle.net/10962/d1005122.
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The demersal fishery off the west coast of South Africa experiences decreased catches per unit effort of hake, Merluccius capensis and M. paradoxus, following the onset of strong south easterly winds. Research has demonstrated that, during daylight hours, Cape hakes migrate vertically in the water column in response to strong south easterly winds, decreasing their availability to the bottom trawl. Hydroacoustic, trawl and environmental data were collected off the West Coast during both calm and wind-swept periods in an attempt to understand the forces that initiate this behaviour, its spatial variability and the implications for demersal trawl estimates of abundance. Near-bottom currents appear to be the primary factor influencing the vertical distribution of the demersal fish community, of which hake constitutes a large proportion, during daylight hours. Correlation between wind and near-bottom currents suggest that the poleward component of the currents increase in velocity within eight hours following the onset of south easterly winds. The fish avoid boundary layers where currents change direction and speed dramatically, and seem to concentrate in waters with relatively stable current regimes. This result questions the assumption of CPUE-based assessment models that hake availability to the bottom trawl is constant or varies randomly. The incorporation of acoustic assessment techniques to demersal surveys has potential, but may be most valuable by supplementing swept-area estimates of abundance, since the sampling efficiency of these methods varies within the water column. The incorporation of wind indices and gear performance data to Cape hake assessment models have been identified as useful considerations for the future.
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Schell, Natalie. "Small-scale fisheries in South Africa : stakeholder's understandings and perceptions of co-management." Master's thesis, University of Cape Town, 2011. http://hdl.handle.net/11427/11172.
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Includes bibliographical references (leaves 154-166).Co-management, which boasts sharing of power and responsibilities amongst all stakeholders involved, has been adopted as an approach to small-scale fisheries management in South Africa. However, the relative success of co-management differs between provinces, provinces which also have different institutional arrangements supporting co-management. In KwaZulu-Natal, arrangements continue to function whereas in the Eastern and Western Cape many have collapsed. Increasing research indicates that fostering shared perceptions (of objectives, approach, desired outcomes and communication infrastructure) towards resource management can improve management practices by obtaining greater community support, increasing understandings of site-specific conditions and improving conflict resolution amongst stakeholders. Thus it is the overall aim of this research project to identify stakeholders’ perceptions towards co-management theory and practice at four case study sites (Mfazazana, Nonoti, Swartkops, Ebenhaeser) to decipher any differences in perceptions and to discuss factors that are influencing these perceptions towards co-management. This has been achieved through a review of the relevant literature, a series of interviews with 40 different stakeholders (primarily fishers and government) and visits to the four case study sites.
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Mullins, Rachel Brenna. "Population genomics analysis of yellowfin tuna Thunnus albacares off South Africa reveals need for a shifted management boundary." Thesis, Rhodes University, 2017. http://hdl.handle.net/10962/57819.
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Yellowfin tuna Thunnus albacares is a commercially and economically important fisheries species, which comprises the second largest component of South Africa’s catch of tuna and tuna-like species. Catches of the species off South Africa are treated as two discrete stocks by the two tuna Regional Fisheries Management Organisations (tRFMOs) under whose jurisdictions they fall. Individuals caught off the Western Cape, west of the boundary between the tRFMOs at 20°E, are included in assessment and management of the Atlantic Ocean yellowfin tuna stock by the International Commission for the Conservation of Atlantic Tunas (ICCAT), and those caught east of this boundary are assessed and managed as part of the Indian Ocean stock by the Indian Ocean Tuna Commission (IOTC). The boundary between these stocks is based on the confluence of the two oceans in this region and does not incorporate the population structure of species. For sustainable exploitation of fisheries resources, it is important that the definition of management stocks reflects species’ biological population structure; the fine-scale stock structure of yellowfin tuna off South Africa is therefore a research priority which this study aimed to address by means of population genomics analyses. Yellowfin tuna exhibit shallow genetic differentiation over wide geographic areas, and as such traditional population genetic approaches have limited power in resolving fishery significant population structure in the species. Herein, a population genomic approach was employed, specifically, genome-wide analysis of single nucleotide polymorphisms (SNPs) discovered using a next-generation DNA sequencing approach, to confer (i) increased statistical power to detect neutral structuring reflecting population connectivity patterns and (ii) signatures of local adaptation. The mitochondrial Control Region (mtDNA CR) was also sequenced to compare the resolving power of different approaches and to permit coalescent based analyses of the species evolutionary history in the region. Neutral SNP loci revealed significant structure within the dataset (Fst=0.0043; P<0.0001); partitioning of this differentiation within the dataset indicated significant differentiation between yellowfin tuna from the Western Cape and the Gulf of Guinea in the eastern Atlantic Ocean, with no significant differentiation between individuals from the Western Cape and Western Indian Ocean regions. This indicates two population units wherein there is a separation of the Gulf of Guinea from the remaining samples (Indian Ocean including Western Cape) that are largely derived from a single genetic population. This pattern was also supported by assignment tests. Positive outlier SNPs, exhibiting signatures of diversifying selection, suggest that individuals from these regions may be locally adapted, as well as demographically isolated. The mtDNA CR did not reveal any significant genetic structure among samples (Fst=0.0030; P=0.309), demonstrating the increased resolving power provided by population genomics approaches, but revealed signatures of historical demographic fluctuations associated with glacial cycles. Based on the findings of this study, it is suggested that yellowfin tuna caught off the Western Cape of South Africa are migrants from the Indian Ocean population, exhibiting significant genetic differentiation from the Atlantic Ocean Gulf of Guinea individuals, and should thus be included in the assessment and management of the Indian Ocean stock. It is therefore recommended that the boundary between the Atlantic and Indian Ocean yellowfin tuna stocks, under the mandates of ICCAT and the IOTC respectively, should be shifted to approximately 13.35°E to include all individuals caught in South African waters in the Indian Ocean stock.
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Fairweather, Tracey Pamela. "An analysis of the trawl and longline fisheries for Merluccius capensis off the west coast of South Africa." Thesis, Rhodes University, 2002. http://hdl.handle.net/10962/d1005061.
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The South African hake resource faces divergent fishing pressures and management issues. Although the resource consists of two species, management was simplified because the resource was only subject to trawl effort and because of the similarity in population parameters, single species assessment models could be adopted. The impact of trawling on the stock is considered to be well understood and the resource has shown recovery since exclusion of foreign vessels. The 1990s were punctuated by major political change and the need for transformation has resulted in an expansion of the number of fishing rights holders. Longlining has been reintroduced and there is no clear understanding of how the combined fishing pressures will affect the population structure of either Merluccius capensis or M. paradoxus. Information is vital to successful management. Fisheries are complex and intricate, and at times appear impossible to control or monitor. An integrated information system provides easily understood graphical explanations of complex issues. This thesis assessed the dynamics of the trawl and longline fisheries between 1994 and 1999 using a geographical information system (GIS). The accessability of a GIS incorporates the needs of scientists, managers and fishing communities. The simple GIS developed in this study revealed shifts in effort, facilitated the calculation of spatially precise catches and biomasses and highlighted the inadequacy of current sampling coverage. Trawlers were shown to fish the same areas consistently during the years investigated, with highest fishing intensity and average CPUE achieved at depths between 300 and 500m. Analysis of the longline sector revealed several similarities to the trawl sector, fishing intensity was highest between 301 and 500m, suggesting that both sectors face a "friction of distance" dilemma. The distribution and abundance of hake, in particular the exploitable proportion of the population, was determined by a combination of depth and substrate type. The selectivity patterns of trawlers and longliners were briefly investigated with the results illustrating that gear selectivity of the M. capensis stock was depth dependent. The deeper fishing occurred, the larger the length-at-selection. As a result, the M. capensis parental stock faces unprecedented fishing pressure. In the absence of reliable species-specific catch data, logistic and linear regression models were developed to split the hake catch into its respective species components. Large discrepancies between the predicted M. capensis catch for the two models were noted. Regression estimates constructed at a finer spatial scale may provide a better fit than the current depth logistic employed by Marine and Coastal Management. A first attempt at assessing the M. capensis resource on the West Coast using an age-structured production model was presented. It was found that a lengthy and accurate M. capensis catch series is required before it is possible to successfully model the dynamics of the stock. It is necessary to incorporate finer spatial detail in the collation of catch data and collection of sampling data. It would be unadvisable to assume that the stock is stable or recovering. The implications of a size/sex relationship must be investigated and properly appraised.
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Potts, Warren Mason. "Towards the development of species-specific fish production models for small reservoirs in Southern Africa." Thesis, Rhodes University, 2004. http://hdl.handle.net/10962/d1005176.
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The fish populations in small southern African reservoirs are largely unexploited and there is potential for fisheries development. However, the development of sustainable fisheries requires reliable estimates of potential yield or production. Empirical models that have been developed to predict fish production only apply to large water bodies and only predict total fish production, not the production of individual species. Small reservoirs generally have few commercially important species and therefore species-specific fish production models are an alternative approach. The small reservoirs of the Eastern Cape are dominated by the moggel (Labeo umbratus). The principal objectives of this thesis were to gain an understanding of the ecology of small reservoirs and the function of moggel in these systems. This information was used to design a research approach to rapidly develop species-specific models for small reservoirs in southern Africa. The limnology of two small reservoirs was compared. During the study period the reservoirs were turbid and showed a warm, monomictic pattern of thermal stratification. Anthropogenic pressure in the reservoir catchments appeared to be the overriding factor increasing the nutrient input to the reservoirs and consequently, influencing the biomass of algae in the reservoirs. The feeding biology of moggel in Katriver and Laing reservoirs was examined. Moggel are detrivorous and successfully digested diatoms. The slower growth rate of moggel in Katriver reservoir was attributed to the poorer nutritional value of the diet as a consequence of the lower concentration of diatoms in the detrital aggregate. The reproductive characteristics of moggel were examined in four reservoirs. Moggel were able to reproduce successfully in the reservoirs. This could be attributed to their r-selected reproductive strategy, with a high fecundity and an extended spawning season and their ability to spawn in a floodplain environment. Differences in recruitment success between years were found to be a consequence of the timing and duration of seasonal rains. The number of mature females in a population and the availability of suitable spawning habitat influenced recruitment success. The life history of the moggel in five reservoirs was compared. Growth appeared to be related to food availability, while mortality was lower in the populations where food was abundant and there were less predatory species. Size and age at maturity were not affected by environmental factors, but were dependent on growth and mortality. Three contrasting methods were used to estimate moggel gillnet selectivity. The Sechin, direct fyke net method and length-structured model all yielded similar results and correction factors obtained from the selectivity study were applied to the gillnet data to estimate the fish population size and structure in each reservoir. Using information from the life history and selectivity studies, the biomass and production of five moggel populations was estimated and related to abiotic and biotic factors in the reservoirs and their catchments. Moggel biomass and production was dependent on the biomass of algae, which was dependent on morphoedaphic characteristics of the reservoirs. Small, shallow reservoirs with a reasonable amount of human habitation in their catchments would sustain the highest algal biomass and provided they had adequate spawning habitat would also have the highest moggel biomass and production. The future research requirements for small reservoir fisheries are outlined and include a three-year program to develop a species-specific production model for any of the dominant species.
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Oosthuizen, Ané. "A development and management framework for a new Octopus vulgaris fishery in South Africa." Connect to this title online, 2003. http://eprints.ru.ac.za/21/.
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Wickens, Patricia Anne. "Interactions of the South African fur seal and fisheries in the Benguela ecosystem." Doctoral thesis, University of Cape Town, 1989. http://hdl.handle.net/11427/22566.
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Bibliography: pages 168-180.This thesis adopts an holistic approach to evaluation of the "seal problem", which encompasses the operational and biological interactions between the South African fur seal and fisheries in the Benguela Ecosystem. The operational interactions are examined using a qualitative assessment, and speculative, single-species simulation models are developed to improve understanding of seal population dynamics, present options for seal management and explore seal-fishery interactions. The models show that the probability of a seal living longer than 20 years is 14%; that the population has increased at a rate of 5.1 % p.a. since the last major census in 1983; that in 1988 there were an estimated 1.5 million seals that consumed over 2 million tons of fish; that although seal population size is usually estimated by multiplying the number of pups by a factor of 4, this factor is very variable and under different culling regimes is usually greater than 4; that historically, the mean population : pup ratio is 4.55. The most effective means of reducing the population is to cull both pups and bulls (the population decrease resulting mainly from reduced pup production caused by disturbance during bull culling). Culling pups is the least effective means of population control. Culling cows alters the population sex ratio drastically and is considered undesirable. To achieve a small or negative population growth rate, more bulls and pups need to be culled than have been taken historically. Each of the fisheries is found to be subject to operational interactions with seals, this being most severe for the purse-seine fishery. The per capita consumption of fish by seals is similar under any management regime so it is not justified to adopt a particular culling strategy to reduce overall consumption. When either seal predation or fishing mortality is reduced, the model simulates an increase in fishery yield of Cape hakes. But there is inadequate understanding of hake population dynamics at present, and depending on the interactions between species, decreased predation may result in increased or decreased fishery yields. This study shows that operational interactions are a real problem and this biases the opinion of fishermen towards seals as competitors for fish resources.
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Godfrey, Brian Peter. "The potential of abalone stock enhancement in the Eastern Cape Province of South Africa." Thesis, Connect to this title online, 2003. http://eprints.ru.ac.za/23/.
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Marire, Juniours, Jen Snowball, and Gavin Fraser. "Regulatory incoherence and economic potential of freshwater recreational fisheries: the trout triangle in South Africa." Routledge, 2014. http://hdl.handle.net/10962/68621.
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Publisher versionWe apply John R. Commons’s negotiational psychology, specifically his principle of sovereignty, to the development of a discordant regulatory culture and its likely impact on the economic potential of recreational fishing. Using South African environmental judicial precedents and other documentation, we formulate six plausible hypotheses. We argue that regulatory incoherence, entitlement insecurity, corporate-dominated social valuation, strategic power coalitions, lack of procedural fairness, and the extent of judicial enforcement of environmental rights help explain the economic potential and isolation of the freshwater recreational fisheries sector. We find a consistent pattern of extraction and monopolization of sovereign power by the Department of Mineral Resources from propertied parties. Thus, regulatory domination is a major mechanism affecting the economic potential of recreational fisheries in the Trout Triangle. While Commons postulated that private property is a sufficient condition for participation in the determination and use of sovereign power, we argue that private/public property is only a necessary condition. The conjunctive sufficient condition is the existence of both regulatory coherence between spheres of government and property.
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Van, der Vyver Johan Samuel Frederik. "The geographic stock structure of chokka squid, Loligo Reynaudi, and its implications for management of the fishery." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1012973.
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It is currently hypothesised that the chokka squid (Loligo reynaudi) consist of a single stock. This was tested through a spatial comparison of the morphology of this species. Forty three morphometric characters were measured from 1079 chokka squid collected from three regions: the south coast of South Africa, the west coast of South Africa, and southern Angola. While no significant differences were found for the hard body parts, results from discriminant function analyses showed the soft body morphometric characters from each of the three regions differed, with an overall correct classification rate of 100% for males and 99% for females in all three regions. Due to the existing model being used to assess the resource currently being updated it was not feasible to apply this model to the area-disaggregated data from this study. Rather, the CPUE trends and catches from the area-disaggregated data were compared against those of the area-aggregated data, as a first attempt to discern any appreciable differences which would suggest the use of disaggregated data in future assessments. Both the trawl and jig CPUE trends from the area-disaggregated analysis differed only slightly from those of the area-aggregated data. Similarly, the spring and autumn biomass trends for the main spawning area (east of 22°E) followed the same trends as for the full area. It is therefore concluded that there is currently no need to assess the resource on an area-disaggregated basis.
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Oosthuizen, Ané. "A development and management framework for a new Octopus vulgaris fishery in South Africa." Thesis, Rhodes University, 2004. http://eprints.ru.ac.za/21/1/A.Oosthuizen_PhD.pdf.
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A new policy incorporating an operational protocol was developed for the establishment of new fisheries in South Africa. The common octopus, Octopus vulgaris was used as a candidate species for the project. The operational protocol consisted of a three-phased development framework, namely information gathering (Phase 0), an experimental fishery (Phase 1) and the final implementation of a commercial fishery (Phase 2). The present study focussed on phase 0 of this theoretical framework and protocol and was implemented by using a proposed octopus pot fishery in South Africa as a case study. Phase 0 included a desktop study, information gathering in the field, an economic feasibility study and the formulation of a Fishery Management Plan and experimental design for the fishery. Information gaps identified during the desktop study were addressed during field investigations into the population structure and biology of O. vulgaris along the southeast coast. Immature females were found to use the intertidal area to feed and grow before migrating to the subtidal area to mature and spawn. Mean size differed substantially between intertidal and subtidal areas, with larger octopus found subtidally. Age and growth trials using tetracycline as a marker showed that O. vulgaris deposit daily growth lines in their beaks. A genetic study showed that there is most likely only one panmitic population along the coast. The economic feasibility study indicated that a longline pot fishery could be feasible provided a 30% catch in 6600 pots/month is attained. Only existing, debt-free vessels should be used in this fishery. The Fishery Management Plan proposed in this study includes management measures such as effort limitation of licences and gear, size restrictions, vessel monitoring systems, and observer programmes. Based on the population dynamics and biology of O. vulgaris it is suggested that a precautionary approach to developing fisheries for this species in both the inter- and subtidal areas along the South African coast.
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De, Greef Kimon. "Booming illegal abalone fishery in Hangberg: Tough lessons for small-scale fisheries governance in South Africa." Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/9187.
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Includes bibliographical referencesMarine capture fisheries around the world are widely perceived to be in a state of crisis, with growing recognition that conventional resource-centred management strategies are insufficient to counter ongoing problems of overexploitation. This is considered particularly true in the small‐scale sector, which employs the overwhelming majority of the world’s fishers but has historically been overlooked. To manage marine resources more sustainably, new approaches to fisheries governance have been sought that recognise the complex nature of fisheries systems, paying attention to the social dimensions of fisheries management in addition to important ecological processes. In South Africa, many of these new approaches have been embraced in a recently adopted policy for the small-scale sector. Attempts to reform marine fisheries have been ongoing in the country since the end of apartheid (a system of legalised racial segregation and white supremacy that ruled for almost 50 years) but have largely failed to bring meaningful change to impoverished fishing communities. Frustration at ineffective reform has contributed to widespread non-compliance – most notably in the abalone fishery, which has collapsed in the face of rampant poaching, driven by a lucrative, illegal export market to the Far East. Although the new small-scale fisheries (SSF) policy has been hailed as a progressive shift in thinking, questions remain about how it is to be implemented. One major challenge will be dealing with illegal fishing. The purpose of this study, was to profile the human dimensions of abalone poaching in the Cape Town fishing community of Hangberg and to draw lessons for implementing the new SSF policy. A qualitative multi-method research approach, based mainly on unstructured interviews and participant observation, was used to access the clandestine fishery and investigate its historical development, current structure, scale and methods of operation and main socio-economic drivers and impacts. It was found that abalone poaching has become deeply embedded in Hangberg, having evolved into a highly organized boat-based fishery in a period of less than 15 years. At least five local poaching groups – representing some 250 individuals in total – currently used dedicated high-powered vessels to access reefs around the Cape Peninsula. Profits earned from poaching are substantial but vary, with poachers operating according to a loose hierarchy and performing a range of different tasks in the fishery. This variation notwithstanding, the illegal fishery appears to have become a mainstay of the impoverished local economy, funding poachers’ expensive lifestyles, in addition to contributing more meaningfully to the livelihoods of an estimated 1000 residents.
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Duna, Elethu Zamandlane Lona. "Progress in implementing the ecosystem approach to fisheries in South Africa in principle and in practice." Thesis, Rhodes University, 2017. http://hdl.handle.net/10962/44879.
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Over the last century, the population of the world has more than doubled, resulting in an increase in seafood consumption (FAO 2010), and placing strain on fisheries wild stocks, their habitats, and the coastal communities that rely on them for food and survival. The ecosystem approach to fisheries (EAF) differs from other management approaches by combining all aspects of ecosystem management, and strives to conserve ecosystem structure, maintain diversity, productivity, and integrity, and to meet human food and economic needs. This study aims to assess how South Africa is progressing in implementing EAF in principle and in practice, to identify challenges, and suggest solutions, where appropriate. The law sets precedence on governance. An assessment of the Marine Living Resources Act, (MLRA) and the South African Policy for Small-scale Fisheries (SSFP) revealed that, although these instruments recognise and contain elements of EAF, this management approach has not been adequately implemented. In practice, the status of implementation of EAF was assessed through the Southern African Sustainable Seafood Initiative (SASSI) and the Ecological Risk Assessments (ERA). The scores of 65 assessments, conducted in 2013 and 2014, were obtained from SASSI. Of the 65 species assessed; 18.4% were listed as Green, 50.8% were listed as Orange and 30.8% were listed as Red. Two methods were used to analyse the data; non-metric multidimensional scaling (NMDS), and cluster analysis in the statistical program R. Analysis of the SASSI assessments indicates that there has been progress in implementing EAF since the World Summit on Sustainable Development in 2002. The high number of Orange and Red listed species however, indicate that major sustainability issues still exist. Species in commercially important fisheries enjoy the bulk of research and management attention compared to other species, including bycatch species, as reflected by a high proportion of Green-rated commercially important species. Based on these results, four fisheries were chosen for further indepth analysis using additional information found in ecological risk assessments: offshore demersal trawl, inshore demersal trawl, West Coast rock lobster fishery and the line fishery. The documents and published literature of the Department of Agriculture, Forestry and Fisheries Internal Scientific Working Groups provided further information. A Wilcoxon signed rank test conducted in the programme R on the results of the ERAs showed that there was a decline in implementation of EAF and reinforced the earlier conclusion that large commercial fisheries, offshore and inshore demersal trawl, were progressing in implementing EAF faster than West Coast rock lobster and line fisheries, which are examples of smaller-scale fisheries that are more accessible to many resource users. Both progress and challenges appeared to be largely influenced by several common factors, which include the presence or absence of positive incentives, co-management, management plans, access, compliance, economic importance, capacity, and the interests of rights holders and other stakeholders.
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Watt-Pringle, Peter Andrew. "Movement bahaviour of three South African inshore sparid species in rocky intertidal and shallow subtidal habitats." Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1005147.
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This study investigated the movement behaviour of three inshore South African sparids – blacktail (Diplodus sargus capensis), zebra (Diplodus cervinus hottentotus) and white musselcracker (Sparodon durbanensis), popular inshore fishery species caught in appreciable numbers along much of the South African coast. The first study component examined movements of juveniles in a rocky intertidal nursery area at Schoenmakerskop near Port Elizabeth. Juveniles in a single gully were tagged with Visible Implant Elastomer (VIE) and resighted at the study site on snorkelling gear over a seven-month period. Tagged zebra and musselcracker displayed limited movement between potential low tide refuges, being observed repeatedly in the same gully over the full duration of the study. However, blacktail displayed greater movements and were seen infrequently in the later period of the study, probably having undergone an ontogenetic habitat shift to subtidal areas. There was evidence that blacktail maintain use of their intertidal nursery over high tide, during which the other two species moved into shallower areas adjacent to their low tide refuge. The results of three national tagging programs were analysed to determine the movement patterns of adolescent and adult fishes. The coast-wide ORI-WWF National Voluntary Tagging Program and two dedicated research programs in marine protected areas (MPAs) at De Hoop MPA and Tsitsikamma National Park (TNP) recorded few large-scale movements of tagged adult blacktail, zebra and juvenile musselcracker. High spatial-resolution data from the TNP suggested movements were usually on scales far smaller than one km. Together with long periods at liberty for many recaptured individuals, this suggests these fishes are longterm residents of small home range areas. However, tagged musselcracker over 600 mm forklength (adults) were observed to make large-scale movements, including some in excess of 800 km from Eastern Cape to KwaZulu-Natal waters. Predominantly eastward movements of adults recaptured during the spawning season indicate seasonal spawning migrations that occur in different regions of the coast. These enable the use of prevailing oceanographic currents to disperse eggs and larvae to suitable rocky nursery habitat. The third component of this study made use of high-resolution data on the temporal and spatial distribution of catches by scientific angling in the TNP to examine the daily activity patterns of the study species in relation to diel and tidal cycles, and habitat use. Blacktail capture probability was correlated with the diurnal light cycle, with peaks close to twilight suggesting elevated crepuscular foraging activity. Catches of blacktail, zebra and small musselcracker were correlated with the tidal cycle, foraging peaking over high tide periods. All three species used shallow inshore habitats extensively for foraging, blacktail showing a preference for sandy areas, while zebra and small musselcracker preferred shallow reef. Capture probability of larger musselcracker, however, was unrelated to habitat, possibly evidence of increasing area and habitat use with an ontogenetic change in diet. The lifetime movement patterns of these three species are discussed in relation to conservation measures and their management in South African fisheries. Restricted movement throughout post-settlement life for blacktail and zebra, and during the juvenile phase for musselcracker, makes local populations vulnerable to overexploitation. At present, MPAs probably play an important role in protecting local blacktail and zebra populations from overexploitation, and limited post-settlement movements mean the degree of larval dispersal between protected and adjacent areas will likely determine the effectiveness of MPAs in enhancing fisheries for these species. By contrast, MPAs likely provide recruits to fisheries for musselcracker during ontogenetic movements and dispersal from MPAs during spawning migrations. MPAs only offer partial protection to adult musselcracker populations in the spawning season, but this could nevertheless be significant under high levels of exploitation.
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Gerber, Werner Hugo. "Enhancing the competitive advantage of the South African cultivated abalone industry." Thesis, Stellenbosch : Stellenbosch University, 2004. http://hdl.handle.net/10019.1/49946.
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Thesis (MSc(Agric))--University of Stellenbosch, 2004.ENGLISH ABSTRACT: The pnmary alm of this study was to investigate the national competitive advantage of the South African abalone industry. A further aim was therefore to investigate the environment, in which the South-African abalone industry operates. Secondary aims included presenting a detailed description of the roleplayers in the South African abalone industry, and considering whether the South African abalone industry can be made more competitive and, if so, how this can be achieved. The achievement of these aims required a framework to establish which data is necessary for the task. The framework selected involved a combination of Porter's Five Forces analysis and Diamond Model. The study suggests that South African abalone firms should promote South African abalone more actively, invest more funds in human resources, and that the industry's faith in government needs to be restored, which can be achieved by improving the services offered by public institutions like the South African Bureau of Standards (SABS), the Department of Trade and Industry (DTI) and Marine and Coastal Management (M&CM).
AFRIKAANSE OPSOMMING: Die doel met die studie was om die nasionale kompeterende voordeel van die Suid Afrikaanse perlemoen industrie te ondersoek. Om dit te bereik, moes die omgewing waarin die industrie fuksioneer ontleed en die rolspelers in die industrie deeglik beskryf word. 'n Verdere doel was om te bepaal of dit moontlik is om die kompeterendheid van die industrie te verhoog, en indien wel, hoe dit bereik kan word. Die raamwerk wat gekies is om die doelstellings te bereik bestaan uit 'n kombinasie van Porter se "Five Farces" analise en "Diamond Model". Die resultate dui aan dat die industrie Suid-Afrikaanse perlemoen meer aktief moet bekendstel, individuele ondernemings meer in hul menslike hulpbronne moet investeer, en dat die industrie se vertroue in die nasionale regering herstel moet word, deur die dienste te verbeter wat deur publieke instellings soos die Suid-Afrikaanse Buro van Stanaarde (SABS), Departement Handel en Nywerheid en Mariene- en Kusbestuur verskaf word.
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Donovan, Bruce. "A retrospective assessment of the Port Alfred linefishery with respect to the changes in the South African fisheries management environment." Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1008298.
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Since the study on the Port Alfred/Kenton-on-Sea/Boknes linefishery by Hecht and Tilney (1989) there have been substantive changes to the linefish management environment in South Africa. Using the Port Alfred linefishery as a model, the aim of this study was to evaluate the effectiveness of the linefish management regulations that were implemented by Marine and Coastal Management (MCM) since 1992, and to assess the behaviour and 'status' of the fishery in response to these changes. Changes to both the licensing structure and catch regulations have had a significant effect on the functioning of many aspects of the Port Alfred linefishery (fishing effort, catch composition, cpue) as well as on the structure of the fishery and its socio-economic profile. Overall commercial cpue decreased from 1985 to 1998. Since 1998 there has been a significant increase in cpue (from 2.3 Kg.fisher⁻¹ hour⁻¹ to a peak of 4.8 Kg.fisher⁻¹.hour⁻¹ in 2005. This was attributed to good catches of geelbek, particularly in 2005, 2007 and 2008 (during these years geelbek contributed an average of 35% to the total landings in comparison to a mean contribution of II % between 1985 and 2004). However, size spectra analysis suggests that the increase in overall cpue since 1998 misrepresents the actual status of the fishery. If geelbek is excluded from the analysis on the grounds that it is the only species in the fishery that is highly migratory, susceptible to recruitment fluctuations and it does not contribute to the catches on a year round basis, then the results suggest that the fishery is still in a declining phase despite the 80% reduction in commercial effort and numerous stricter catch regulations (e.g. size/bag limits). Furthermore, the cpue of silver kob, which has been the "mainstay" species of the fishery, has consistently declined over the last 23 year period (from 1.69 Kg.fisher⁻1 .hour1 in 1986 to 0.86 Kg.fisher⁻1.hour⁻1in 2007). The substantial reduction in commercial effort in the fishery from 33 vessels in 2001 to 13 in 2002 resulted in a shift from commercial to recreational fishing. The number of active commercial vessels in Port Alfred alone decreased from 29 in 1989 (Hecht 1993) to four in 2008. During the same timeframe, the number of regularly active recreational vessels had almost doubled (16 in 1989 to 26 in 2008). Despite the greater number of recreational boats in the fishery they only landed approximately half the average yearly tonnage of the commercial vessels (21,5 and 44,7 tonnes,annum-I , respectively) between 2006 and 2008, This was ascribed to the differences in catch regulations for the two sectors, Furthermore, it was speculated that increasing operating costs and narrowing profit margins have contributed to lower levels of compliance in both the commercial and recreational sectors since 2006, For example, 16% of silver kob landed during 2006-08 were under the minimum size, Despite the changes made to the regulations since 1998 and the 60,6% reduction In legislated commercial effort in the fishery between 2001 and 2002 it was concluded that the fishery has continued to decline, Except for the good recruitment of geelbek (which may be due to regulatory changes made in 1992) the changes in the management environment have had no measurable positive effect on this fishery, It is recommended that commercial effort should not be allowed to increase beyond the current number of active boats, that there should be an area restriction on all commerciallinefish vessels, that the current recreational bag limit for silver kob should be re-assessed, there should also be a concerted and nationally funded effort to educate recreational anglers about the merits of catch and release, and the frequency of catch inspections of both sectors should be increased,KMBT_363
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De, Kock Leon. "Development of abalone and sea turtle aquaculture ventures for export purposes : a technical, marketing and financial feasibility analysis." Thesis, Stellenbosch : Stellenbosch University, 1998. http://hdl.handle.net/10019.1/50932.
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Thesis (MBA)--Stellenbosch University, 1998.ENGLISH ABASTRACT: The techniques for animal reproduction and husbandry for both abalone and sea turtle farming have been well established and researched over the last decade. Although market related data seems to be scarce, marketing analysis reviewed and conducted as part of this study suggests that extensive markets exist for live cocktail size abalone and sea turtle products, especially in the East Asian countries. A decline in natural resources and increased demand resulted in a fast expanding niche market for these products. This study shows that development of an abalone farm in South Africa for the production of cocktail size (±80 mm; ±100 g) is a highly profitable venture. Economic feasibility analysis indicated that the development of an abalone farm capable of producing 150 tons annually should result in a rate of return in excess of 50% over a seven-year investment period. On the other hand, sea turtle farming is a less profitable investment with Green turtle farming yielding a return of approximately 25% and Hawksbill farming yielding a return closer to 30% over a seven-year investment period. According to the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), all sea turtle species have been listed as endangered or threatened. Currently all countries who are members of CITES are prohibited from international trade in sea turtles or sea turtle products. Prospective entrepreneurs wishing to establish a sea turtle farming venture have to adhere to stringent regulatory and control measures, a major obstacle in the development of a profitable enterprise. Both abalone and sea turtle farming have long payback periods, due to the slow growth-rates of the investigated species. In order to produce animals in a time frame that is economically viable, artificially formulated feeds have to be used. The usage of artificially formulated feeds proved to be a major expense, especially in the case of sea turtle farming.
AFRIKAANSE OPSOMMING: Die tegnieke vir die reproduksie, onderhoud en groei van beide perlemoen en seeskilpad akwakultuur boerderye is goed gevestig en nagevors oor die afgelope dekade. Alhoewel mark verwante data skaars is, dui bemarking analises aan dat 'n enorme mark bestaan vir lewendige "cocktail" grootte perlemoen en seeskilpadprodukte, veral in Oos Asie. 'n Afname in natuurlike hulpbronne en 'n toename in aanvraag, het 'n vinnige "nis" mark vir die produkte tot gevolg gehad. Die ontwikkeling van 'n perlemoen boerdery vir die produksie van "cocktail" grootte (±80 mm; ±100 g) perlemoen kom voor as 'n hoogs winsgewende onderneming. 'n Ekonomiese winsgewindheidsanalise het getoon dat die ontwikkeling van 'n perlemoenplaas, met 'n produksie van sowat 150 ton perlemoen jaarliks, 'n opbrengs van oor die 50% oor 'n sewe jaar investeringsperiode teweeg sal bring. Seeskilpad boerdery, aan die ander kant, kom as 'n minder winsgewende belegging voor, waar Groen seeskilpad boerdery 'n opbrengs van ongeveer 25% en Hawksbill boerdery 'n opbrengs van min of meer 30% oor 'n sewe jaar beleggings periode toon. Volgens CITES (Convention on International Trade in Endangered Species of Wild Fauna and Flora) is alle seeskilpaaie gelys as bedreig. Alle lande wat huidiglik lede is van CITES, word van die reg voorbehou om internasionale handel te dryf in seeskilpaaie of seeskilpadprodulcte. Voorgenome entrepeneurs met die begeerte om 'n seeskilpadboerdery te begin, sal voor streng maatreels en beheer- maatstawwe te staan kom, wat 'n groot stuikelblok is in die ontwikkeling van 'n winsgewende seeskilpadplaas. Beide perlemoen- en seeskilpadboerderye het lang terugbetalingsperiodes, 'n waameming wat verduidelik kan word aan hand van die stadige groei-tempo's van die bestudeerde spesies. In orde om diere in 'n spesifieke tydsperiode te produseer wat ekonomies winsgewend is, moet daar van artifisieel geformuleerde voeding gebruik gemaak word. Die gebruik van geformuleerde voeding. is egter duur, veral in die geval van seeskilpadboerderye.
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Raemaekers, Serge. "Rethinking South Africa's small-scale fisheries management paradigm and governance approach : evidence from the Eastern Cape." Thesis, Rhodes University, 2010. http://hdl.handle.net/10962/d1003921.
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This thesis presents a first analysis of how the South African fisheries authority (MCM) has utilised its fisheries management toolbox and governance framework in response to the emerging biological, economic and social challenges of post-apartheid fisheries in the Eastern Cape Province. Despite recognition of the socio-economic circumstances of traditional subsistence fishers in the region, the national fisheries management authority implemented a 'target resource orientated' management approach similar to that used for South Africa's rights-based commercial fisheries. Anecdotal evidence of entrenched illegal fishing for abalone, spiny lobster, and species targeted by subsistence fishers however suggested that MCM's management approach was encountering serious problems, as the needs and circumstances of inshore fishers and fishing communities were not adequately being understood and addressed. A review of fisheries management literature therefore shaped the hypothesis that an underlying governance problem was responsible for the symptoms of management failure being observed. In this regard, management is seen as more concerned with the technical and regulatory measures of the day-to-day operations of regulated fisheries, while fisheries governance needs to take account of "the sum of legal, social, economic and political arrangements used to manage fisheries ... ". Thus, governance includes policy making and management decision-making, with simultaneous recognition of issues outside of the fisheries sector. It thus appeared that the underlying problem was rather one of broader fisheries governance and inappropriate governance objectives with consequent inappropriate resource management arrangements. This thesis set out to gather evidence to test this hypothesis.
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Seti, Simpiwe. "Small-scale fisheries as a vehicle for rural development : a case study of two villages in the former Ciskei, Eastern Cape Province, South Africa." Thesis, Rhodes University, 2003. http://hdl.handle.net/10962/d1006016.
Full textAbstract:
This thesis examines small-scale rural fisheries which were initiated in two villages by the Department of Ichthyology and Fisheries in conjunction with the Institute of Social and Economic Research in 1997. The main objective for undertaking the study was to determine the potential of the fisheries to serve as viable and sustainable options that could contribute towards rural development in the area of study. To examine the contribution made by the small-scale fisheries towards rural development in the villages, it is imperative to have an understanding of the context in which they were established as well as the prospects for sustainable development. It is argued in this study that despite the significant contribution made by inland rural fisheries in improving rural livelihoods they are still accorded minimal support and attention in South Africa. As an illustration of the important role played by rural fisheries, case studies from Malawi and Zimbabwe have been drawn into the study with a view to providing lessons for rural areas of South Africa. The study took place at a time when natural resources in the villages were significantly declining and environmental degradation reaching uncontrollable proportions, so there is an urgent need to secure an alternative mode of subsistence for the population in the villages. Development interventions by the state and non-governmental organisations in the study area have not been sustainable and they collapsed within a short period of time. A case in point is the Tyefu irrigation scheme, which was initiated in the villages but, owing to various factors, it failed leaving the villagers with a diminished mode of subsistence, thus providing the impetus for the implementation of small-scale rural fisheries. In order for small-scale fisheries to be sustainable it is essential to adopt models that are aimed at sound natural resource use and management. This study has raised various issues pertinent to natural resource use and management in the study area. A model for management of natural resources that involves and aims to empower local communities in the management of the fisheries is presented in the study. It has also been demonstrated that rural fisheries in the study area comply with the model. Finally, the study draws the conclusion that small-scale fisheries in the villages contribute towards rural development, however, there are constraints that need to be eradicated.
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Esterhuyse, Willem Petrus. "The sustainability balanced scorecard : its theory and applications to companies operating within the South African fishing industry." Thesis, Stellenbosch : University of Stellenbosch, 2008. http://hdl.handle.net/10019.1/816.
Full textAbstract:
Thesis (MBA (Business Management))--University of Stellenbosch, 2008.AFRIKAANSE OPSOMMING: Verskeie korporatiewe fiaskos gedurende die afgelope dekade het wêreldwye opskudding veroorsaak met die gevolg dat daar vanaf ‘n nuwe oogpunt gekyk word na die wyses waarop korporasies bestuur word. Terselfdertyd is daar ‘n wêreldwye belangstelling gekweek in volhoubare ontwikkeling en korporasies se bydrae daartoe. Dit, tesame met korporatiewe bestuur, het tot die gevolg gehad dat die fokus vanaf die tradisionele finansiële verslaggewing geskuif het na rapportering op die sogenaamde “Tripple Bottom Line” en meer en meer maatskappye oor die wêreld genereer en publiseer deesdae op hul ekonomies-, maatskaplike-, omgewingsverantwoordelikhede en prestasies. Gou is daar egter besef dat rapportering en die opstel van beleide self nie genoeg is nie en een van die die grootste uitdagings aan korporatiewe bestuurders tans is om te verseker dat hul korporatiewe bestuurstelsels hul volhoubare strategieë ondersteun om te verseker dat die strategieë in hul maatskappystelsels en prosesse geintegreer is. Kaplan en Norton het in 1992 die Gebalanseerde Telkaart ontwikkel. Die telkaart is as instrument voorgestel om strategieë in aksie oor te skakel. Die telkaart erken dat die tradisionele finansiële maatstawwe nie voldoende is om die volhoudbare sukses van die maatskappy te verseker nie en skep ‘n balans tussen nie-tradisionele maatstawwe oor vier areas: finansieël, kliënte, interne prosesse en leer en groei. Alhoewel daar verskeie gevallestudies in literatuur voorkom waar Gebalanseerde Telkaart implementering gefaal het, het navorsing bewys dat in gevalle waar dit wel suksesvol geimplementeer is, die telkaart ‘n dramatiese verskil aan die maatskapy se prestasie gemaak het. Daar moet dus besef word dat die telkaart wel sy tekortkominge het en dat die implementering daarvan oordeelkundig moet geskied. Gedurende die 21st eeu het outeurs die potensiaal van die Gebalanseerde Telkaart om korporatiewe volhoudbaarheidsstrategië in aksie oor te skakel raakgesien om sodoende die gaping tussen volhoudbare korporatiewe bestuur en die integrasie van beleid en strategieë in die maatskappy prosesse en -stelsels te oorbrug met die integrasie van volhoudbare maatstawwe in die Gebalanseerde Telkaart. Wêreldwyd is die visvangbedryf gedurig onder die kollig vanweë sy impak op die omgewing en die Suid-Afrikaanse visvangbedryf word nie uitgesluit nie. Die visbedryf is ‘n bron afhanklike bedryf en maatskappye moet teen mekaar meeding vir toegang tot die ontgunning van die bron. Vanuit ‘n ekonomiese en ‘n omgewings oogpunt is dit dus van uiters belang dat maatskappye in die bedryf volhoudbare strategieë toepas om die hernubaarheid van die bron te verseker. Suid-Afrikaanse maatskappye bevind hulself egter in ‘n unieke situasie in terme van maatskaplike verantwoordelikheid vanweë die onregmatighede van die apartheidstelsel en maatskaplike verantwoordelikheid moet dus transformasie insluit. Daarvoor het die Departement van Handel en Industrie reeds Die Swart Ekonomiese Bemagtigings Telkaart ingestel om die vordering van maatskappye te meet. Hierdie telkaarte vorm dus ‘n uitstekende basis vir die volhoudbaarheids gebalanseerde integrasie, nie net om te voldoen aan die legislatiewe regulasies nie, maar ook om die geleenhede wat daaruit kan voortspruit ten volle te benut. Hierdie navorsingsverslag ondersoek dus die skakels tussen korporatiewe bestuur en korporatiewe volhoudbaarheid, die teorië rondom die Volhoudbaare Gebalanseerde Telkaart en die moontlike toepassing daarvan op die Suid-Afrikaanse visbedryf.
ENGLISH SUMMARY: Over the past decade outrageous corporate fiascos has resulted in a renewed interest in Corporate Governance and the way Corporates are managed. At the same time sustainable development and the Corporate contribution and Corporate sustainability has gathered worldwide interest in both institutional and corporate spheres. This has triggered new expectations for business transparency and has shifted the focus from traditional financial reporting to reporting on the organization’s impact and performance on the triple bottom line. More companies from across the globe are developing and reporting on their economic, social- and environmental responsibility and performance. It soon became clear that reporting on broad policy is simply not enough and one of the biggest challenges of corporate managers today are to ensure that their sustainable strategies and policies are integrated into their organizational governance structures and processes. Kapland and Norton have developed the Balanced Scorecard in 1992 to provide business managers with a management tool to translate their strategies into action. The scorecard recognizes that traditional financial measurements is not enough to ensure the continued success of organizations and creates a balance between non traditional measurements across four perspectives: financial, customers, internal processes and learning and growth. Although various case studies exist about Balanced Scorecard implementation, empirical research have indicated substantial performance improvement at organizations that have successfully implemented the Balanced Scorecard. Implementation thereof therefore has to be carried out with caution. During the 2000’s authors has recognized the potential of the Balanced Scorecard to translate Corporate sustainability strategies into action and bridge the gap between the way corporates are governed and sustainability by integrating sustainability measures into the Balanced Scorecard for the creation of the sustainability Balanced Scorecard. Fisheries, world wide are continually under the spotlight as a result of their impact on the environment and the South African fishing industry is certainly not excluded. Fisheries are a resource dependent industry and companies have to compete against each other for access to these resources. Apart from its environmental impact it is therefore of outmost importance that managers within the industry considers all the sustainability aspects in their organizational structures. This research report thus explores the link between Corporate Governance and Corporate Sustainability, the theory surrounding the sustainability Balanced Scorecard and the possible application thereof in order to ensure the long term sustainability of the industry.
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Kaminsky, Alexander. "Social capital and fisheries co-management in South Africa: the East Coast Rock Lobster Fishery in Tshani Mankozi, Wild Coast, Eastern Cape." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1003110.
Full textAbstract:
It is evident that natural fish stocks are in rapid decline and that millions of people around the world rely on these resources for food and for securing a livelihood. This has brought many social scientists, biologists and fisheries experts to acknowledge that communities need to take more control in managing their natural resources. The paradigm shift in fisheries management from a top-down resource orientated control to a participatory people-centred control is now being advocated in many maritime nations in facilitating community-based natural resource management. At the heart of these projects is the establishment of institutions and social networks that allow for clear communication and information sharing, based on scientific data and traditional knowledge which ultimately allow empowered communities to collectively manage their resources in partnership with government, market actors and many other stakeholders. Central to the problem is the issue of access rights. In many situations where co-management of natural resources through community-government partnerships is advocated, the failure of coastal states to provide adequate legislature and regulatory frameworks has jeopardised such projects. A second issue is the failure of many states to provide adequate investments in social and human capital which will enable communities to become the primary stakeholder in the co-management of their natural resources. Whilst investments like capacity building, education, skills training and development, communications and institution building can initially require high financial investments, the regulatory costs for monitoring, controlling and surveying fish stocks along the coastline will go down as communities take ownership of their resources under sustainable awareness. The main unit of investment therefore is social capital which allows for the increase in trust, cooperativeness, assertiveness, collective action and general capabilities of natural resource governance. High levels of social capital require good social relations and interactions which ultimately create a social network of fishers, community members and leaders, government officials, market players, researchers and various other stakeholders. Co-management thus has an inherent network structure made up of social relations on a horizontal scale amongst community members as well as on a vertical scale with government and fisheries authorities. These bonding relations between people and the bridging relations with institutions provide the social capital currency that allows for a successful co-management solution to community-based natural resource governance. The South African coastline is home to thousands of people who harvest the marine resources for food security and securing a basic income. Fishing is a major cultural and historical component of the livelihoods of many people along the coastline, particularly along the Wild Coast of South Africa located on its South-eastern shoreline. Due to the geopolitical nature of South Africa’s apartheid past many people were located in former tribal lands called Bantustans. The Transkei, one of the biggest homelands, is home to some of South Africa’s poorest people, many of whom rely on the marine resources. By 1998 the government sought to acknowledge the previously unrecognised subsistence sector that lived along the South African coastline with the promulgation of the Marine Living Resources Act. The act sought to legalise access rights for fishers and provide opportunities for the development of commercial fisheries. The act and many subsequent policies largely called for co-management as a solution to the management of the subsistence sector. This thesis largely explains the administrative and legislative difficulties in transporting the participatory components of co-management to the ground level. As such co-management has largely remained in rhetoric whilst the government provides a contradictory policy regarding the management of subsistence and small-scale fishers. This thesis attempts to provide qualitative ethnographic research of the East Coast Rock Lobster fishery located in a small fishing village in the Transkei. The fishery falls somewhere on the spectrum between the small-scale and subsistence sector as there are a basket of high and low value resources being harvested. It will be argued that in order to economically and socially develop the fishery the social capital and social networks of the community and various stakeholders needs to be analysed in order to effectively create a co-management network that can create a successful collective management of natural resources thereby sustaining these communities in the future.
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Jordan, Tia. "An assessment of the small-scale fisheries in the Kogelberg district of the Western Cape, South Africa." Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/997.
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Small-scale fisheries play a critical role in communities by contributing to food security, poverty alleviation and source of income. The study focused on the Kleinmond small-scale fishery and estimated the current economic value of the fishery as well as exploring the potential for increasing this and also whether it is being used in a way that ensures sustainable harvesting of the marine resources. It was important to evaluate the ecological, economic and social dimensions of the fishing community in order to address the problems currently facing the community. The study draws on previous research done in the Kleinmond area. Data were collected to update and complement previous research and addresses current research. In order to investigate the fisheries catch contribution in the area, data were obtained from the Department of Agriculture, Forestry and Fisheries. Three different questionnaires were developed and conducted in face-to-face formal and informal interviews with the various stakeholders (n=42) in the value-chain. Interviews were also conducted telephonically with other stakeholders and a focus group was formed to supplement previous available data. Simple economic models were developed for the fisheries working from the Kleinmond harbour, which were used to estimate the gross and net economic value of catches for individual right-holders, as well as the Kleinmond area as a whole. The economic models used in this study showed that the West Coast rock lobster Jasus lalandii, fishery was the primary source of income for small-scale fishers. This was due to the rock lobsters being sold to the export market as a high-valued commodity, whereas the linefish were sold to the local market as a lower-valued commodity. However, linefish were found to be more of a commodity to the community as a portion would be retained for personal consumption. The linefishers were concerned in that over the past couple of years, snoek Thrysites atun have been absent the Kleinmond area, resulting in and the fishing effort shifting to a resident species Cape bream Pachymetopon blochii. Whereas West Coast rock lobster were considered to be harvested sustainably under the current total allowable catch strategy, there was concern for the future of the fishery because of the occurrence of illegal fishing, both locally and nationally. Small-scale fisheries in the Kleinmond community are largely dependent on fishing resources, even though the industry is only marginally profitable. Future management measures should concentrate on optimising the value-chain to provide both sustainability for the resources and improve the livelihoods of the community.
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Muller, Cuen. "Evaluating the importance of mangroves as fish nurseries in selected warm temperate South African estuaries." Thesis, Nelson Mandela Metropolitan University, 2017. http://hdl.handle.net/10948/12080.
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The value of mangrove habitats as fish nurseries was assessed by comparing communities of early stage and juvenile fishes between estuaries with and without mangroves. Early stage fishes were sampled using boat-based plankton towing while juveniles were sampled by seine netting. Sampling took place at five sites spaced 1 km apart starting near the estuary mouth in four estuaries along the temperate coastline of the Eastern Cape Province of South Africa. Four estuaries were selected based on shared similarities which included catchment area, estuarine area and shared habitats barring the presence of mangroves which occupied the river margins of two systems. Results revealed that early stage and juvenile fish communities (both marine- and estuary-spawned) were similar between systems with and without mangrove habitats. Differences in fish communities among estuaries were rather attributed to axial salinity gradients associated with greater freshwater input, while season and temperature produced significant variances in fish densities with Generalised Additive Models revealing responses of communities to these variables. A common estuarine-dependent fish, Rhabdosargus holubi (Family Sparidae), was further investigated to determine habitat use, residency and dietary patterns in different mangrove habitats. High habitat residency in this species was revealed during a short-term tagging study using Visible Implant Elastomer tags and long-term isotope analysis in juveniles sampled from two contrasting mangrove habitats. A wider feeding niche was observed in an eelgrass-red mangrove connected habitat when compared with more exposed white mangrove areas. Low dependence on mangrove habitats in temperate estuaries is likely due to their tidally dominated inundation and limited refuge potential due to smaller area coverage by mangroves in temperate estuaries. Relatively lower primary productivity in warm temperate mangrove areas, relative to their tropical counterparts, provides no significant feeding advantage or refuge opportunities relative to other available habitats in these estuaries. Warm temperate estuaries, which are both spatially and temporally highly variable, instead host species which are habitat generalists, able to capitalise on these highly dynamic environments.
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Newcombe, Hylton Cecil. "Contribution towards the development of a management plan for the baitboat and sport fishery for tuna in South Africa." Thesis, Rhodes University, 2012. http://hdl.handle.net/10962/d1005092.
Full textAbstract:
Tuna are of significant global economic importance and a prime food source. Increased levels of fishing have resulted in many stocks being under threat and a number of species are considered to be overfished. The South African tuna industry has had limited management attention from the South African fisheries management agency. A recent development has been an increase in the number of tuna caught by small vessels that target the fresh tuna market in South Africa and overseas. This has highlighted the importance of developing a holistic management plan for the sector and creating an awareness, among vessel owners, of the importance of compliance with initiatives such as the Marine Stewardship Council (MSC). The South African tuna fishery comprises three sectors: baitboat, sport and longline, all of which are currently in need of acquiring more biological and fisheries data. This project was initiated to collate existing information and to collect additional information where possible. This encompassed a qualitative and quantitative assessment of the size and shape of the tuna fishing industry, which included estimates of total catch, effort, catch-per-unit-of-effort (CPUE) and stock structure (obtained through comparative estimates of age and growth), as well as socio-economic and economic information. A technique involving an examination of specific vertebrae was used to obtain age-growth information for T. albacares. These data were used to estimate von Bertalanffy (VBGF) growth parameters: F 2 1. , k 0.1 , and t₀ -0. 1 year. No significant differences in growth parameters were found in yellowfin tuna (Thunnus albacares) from different localities around the South African coast, i.e. from the south eastern Atlantic and the south western Indian Ocean. In addition, growth did not differ between South Africa and other regions (Draganic and Pelzcarski 1984, Fonteneau 1980, Gascuel et al. 1992, LeGuen and Sakagawa 1973, Lehodey and Leroy 1999, Lessa and Duarte-Neto 2004, Shuford et al. 2007, Stequert et al. 1996, Wild 1986, Yang et al. 1969). Further substantiation of the above-mentioned observations was found by recording differences in the sizes of fish caught in the inshore (baitboat and sport fishery vessels) and offshore (large pelagic longline vessels) sectors of South African tuna fisheries. A significant difference between the regions — in terms of the size of fish caught inshore — was noted, with mostly-juvenile fish being caught in KwaZulu-Natal (5.4 ± 3.5kg), sub-adult fish in the Eastern Cape (26.2 ± 13.4kg), and adult fish in the Western Cape (42.3 ± 14.4kg). Since mostly-adult fish were caught offshore by longliners, with no significant differences between regions, it is however possible th at adult fish predominantly inhabit the offshore region. Yellowfin tuna caught by the large pelagic longline fishery in the three managerial zones (A, B and C) were predominantly adult fish of similar size, namely Zone A: 38.9 ± 6.9kg; Zone B: 28.7 ± 4.6kg, and Zone C: 36.0 ± 5.1kg. The recreational ski boat sport fishery has remained stable, in terms of participation, consisting mostly of white middle aged males in the top 25% of household income distribution, having either permanent occupational status or being retired. Fishers within this sector are willing to incur great expense to partake in the fishery and they provide an important economic contribution to coastal towns, particularly in the Eastern Cape. The total catch (of 83t) of yellowfin tuna by the competitive sport fishery within the Western and Eastern Cape regions was considerably lower than that of commercial tuna baitboat catches, which amounted to 186t, and the large pelagic longline sector that caught t in 200. It is however likely that the competitive sport fishery's total yellowfin tuna catch (of 83t in 2009) of the Eastern and Western Cape competitive sport fishery was considerably less than the total yellowfin tuna catches of the whole South African deep-sea sport fishery. Longfin tuna are the primary target species of South Africa‘s baitboat fisheries, comprising an average of 86% of the total catch and generating ZAR49 million in employment income in 2002. South Africa was responsible for 20% of the total longfin tuna annual yield in 2004 in the southern Atlantic Ocean, behind Taiwan with 59%. However, yellowfin tuna only contributes a small percentage towards total catches (8.4 ± 8.2% between 1995 and 2009), generating ZAR1.3 million in employment income in 2002. Of the four vessel categories comprising the tuna baitboat fishery, ski boats had the highest yellowfin tuna CPUE in 2009 (117 ± 62 kg.vessel⁻¹.day⁻¹) and the lowest effort. The ski boats sector is the most opportunistic fishery as they are only active when either longfin or yellowfin tuna are in high abundance. At such times catches are guaranteed, so can be expected to offset expenses. In 2009 the CPUE for yellowfin tuna for 15–19m vessels and freezer deckboats was 12 ± 20kg.vessel⁻¹.day⁻¹ and 3 ± 6kg.vessel⁻¹.day⁻¹, respectively. These vessels specifically target longfin tuna when they are in abundance. Since the start of the tuna baitboat fishery in 1995, there has been a substantial increase in the number of new entrants. In 2002 this sector had a fleet size of 82 vessels with a capital value of ZAR163 million and a total employment income of ZAR58 million, employing 2 173 fishers, of which 87% were black African. The commercial tuna baitboat fleet has subsequently grown to 200 vessels and 3600 crew, with 110 active vessels fishing for a combined fleet average of 46 days per year. There are a high number of owner-operated vessels. Since 2007 the fishery's profit to cost ratio has been low due to the low abundance of tuna stocks off the coast of South Africa, which has resulted in poor catch returns, placing economic pressure on the fishery. The baitboat industry is a low-profit-margin fishery with a total net catch value worth ZAR90 million in 2009 (Feike 2010). The abundance of yellowfin tuna influences profit margins, with very high profits being made when abundance and catches are high. The large pelagic longline fishery has a total allowable effort of 43 vessels of which only 30 vessels fished during 2009, when a reported 766t of yellowfin tuna were caught, representing a total tonnage far in excess of that obtained by the combined effort of the baitboat and sport fishery. It is, however, assumed that considerable underreporting of catches takes place within this fishery, which means that the estimated total net catch value of ZAR100 million could, in fact, be much higher. Such underreporting of catches is of great concern for this fishery, as is the high bycatch of Chondricthians spp. that significantly outweighs imposed regulatory limits (DEAT 2007). The present study demonstrates the current lack of comprehensive catch and effort data for the sport, baitboat and longline fisheries as well as the serious limitations and flaws associated with current databases. Results from the present study have drawn attention to a number of high-priority research needs, as outlined below. (1) A major lack of comprehensive catch and effort data for the sport fishery, which can be rectified by focussing on obtaining more competition data, as well as high-quality catch and effort and socio-economic information, as opposed to relying on information from non-club anglers (Gartside et al. 1999, Williams 2003, Cass-Calay 2008). Acquisition of such data is relatively inexpensive: the location of organized clubs and their frequent competition meetings provide widespread coverage along the Southern African coastline. Such data acquisition efforts have the potential to provide reliable information on spatial catch trends. (2) Validation of vessel catch return data is required for commercial fisheries and on some recent data that has emerged from studies of catch rates and trends for target species, particularly in the longline fishery. In this context it should be noted that the most recent peer-reviewed publications on this exploratory fishery were published more than a decade ago (Kroese 1999, Penny and Griffiths 1999). Additional studies need to be undertaken and journal articles published on the current stock status of South African catches of yellowfin and bigeye tuna and swordfish.
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Weyl, O. L. F., Warren Mason Potts, and Q. Rouhani. "The need for an inland fisheries policy in South Africa : a case study of the North West Province." Water SA, 2007. http://hdl.handle.net/10962/d1008056.
Full textAbstract:
In contrast to many other African countries, inland fisheries in South Africa are poorly developed and the fish populations in many of the country’s 3 000 major dams are under-utilised. While the primary purpose South Africa’s dams is to supply water for domestic and agricultural use, there has been an increasing realisation that their fish populations could make a contribution to food security through the establishment of capture fisheries. Historically, the fish in most South African dams have primarily been utilised for recreational fishing purposes, as subsistence use was criminalised by the apartheid regime in all waters except in the former homeland areas. This legacy persists as many of South Africa’s rural communities do not have a fishing tradition and there is a lack of an institutional framework to facilitate managed and sustainable access to the fish resource in inland waters. Current utilisation of many inland dams is often complicated by the existence of multiple authorities and interest groups, often with competing agendas. As a result, the economic potential of these water bodies is unknown and often grossly underutilised. Our study outlines a case study of fisheries resources in the North West Province of South Africa that could be used for the creation of income and food security for local communities through the development of subsistence, commercial, and recreational fisheries. The study identifies the lack of guidelines for the development of inland fisheries and the lack of an inland fisheries policy, both at the provincial and national level, as major bottlenecks for the sustainable development of these resources and outlines possible focal areas for intervention.
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Kemp, J. O. G. "Mariculture as a means to add value to the east coast rock lobster Panulirus homarus rubellus subsistence fishery : a physiological approach to define transport and growout protocols for wild caught juveniles." Thesis, Rhodes University, 2009. http://hdl.handle.net/10962/d1005144.
Full textAbstract:
In a context of declining capture fisheries and public pressure for greater access to marine resources, marine aquaculture is receiving increasing interest from the South African government as a means to increase the diversity of economic activities in coastal regions, thereby providing employment and reducing poverty. The east coast rock lobster Panulirus homarus rubellus is currently harvested by subsistence fisherman along the former Transkei coastline of south-east South Africa and presents a possible opportunity for ongrowing wild juvenile lobsters in culture facilities. Lack of compliance coupled with poor enforcement of the minimum size limit (65 mm carapace length) has resulted in the ongoing harvest of undersize size lobsters by subsistence fishers. Generally, fishers either consume these undersize lobsters or sell them to tourists for low prices. In line with international trends in rock lobster aquaculture, interest has subsequently arisen in the possibilities of ongrowing these undersize lobsters as a means of adding value to the P. h rubellus resource for subsistence fishers. The aim of this physiological study was to assess the biological feasibility of harvesting, transporting and culturing wild caught juvenile lobsters, thereby provide empirical data to inform the development of suitable transport and culture protocols. The experimental objectives were to asses the effect of temperature on growth and survival of P. h. rubellus, as well as the effects of a suite of extrinsic and intrinsic factors on ammonia excretion and oxygen consumption. Juvenile lobsters were collected by hand from near-shore reefs (2-15 m depth) off Mdumbi in the former Transkei, Eastern Cape Province and transported by road (7 hours) to the Port Alfred Marine Research Laboratory where they were held in a recirculating culture system. The effect of temperature over a range of 9.7 °C (18.9±0.7 to 28.6±1.5 °C) on the growth and survival of juvenile P. h. rubellus fed a diet of fresh mussel flesh was investigated. Specific growth rate (SGR) was significantly different between temperatures (p = 0.01), with the highest values recorded for the 24 °C and 28 °C treatments. There was no significant difference in moult increment (MI) between temperatures, however, intermoult period (IMP) differed significantly between temperatures (p = 0.0015) with mean IMP lowest at 24 °C, although not significantly different from the means of the 26 °C and 28 °C treatments. IMP was highest at 19 °C and 21 °C. Apparent feed intake was significantly different between treatments (p < 0.0001) and exhibited a strong positive correlation with increasing temperature. Food conversion ratio (FCR) differed significantly between temperatures (p = 0.02) with 24 °C exhibiting the most efficient FCR. The results for growth rate and food conversion efficiency suggested that 24 °C is optimal for the growout of juvenile P. h. rubellus. In the second study, the effect of body weight, emersion, daily rhythm, feeding and ambient ammonia on the total ammonia nitrogen (TAN) excretion rate was investigated. Body weight (n = 16, range of 16.8 – 322 g) was positively correlated to daytime TAN excretion rate (mg h⁻¹). Re-immersion after one hour emersion in a moist environment was characterized by a significant increase in TAN excretion rate for the first hour compared to pre-immersion levels. The amount of TAN excreted during this period was as expected if basal TAN excretion rates were maintained during emersion. TAN excretion rates returned to pre-emersion levels by the end of the second hour. There was no evidence of a daily rhythm in TAN excretion rate for P. h. rubellus. TAN excretion rates were elevated following feeding. An initial peak in TAN excretion rate after seven hours (7.58 times pre-feeding rate) was followed by a smaller peak after 13 hours (6.69 times pre-feeding rate). TAN excretion rate dropped to levels not significantly different from pre-feeding levels after 23 hours and consistently returned to pre-feeding levels after 42 hours. The TAN excretion rates of lobster exposed for two hours to an ambient TAN concentration of 1.02±0.10 mg l⁻¹ and 2.3± 0.2 mg l⁻¹ were not significantly different from TAN excretion rates recorded at low ambient water TAN prior to exposure. Exposure to an ambient TAN concentration of 4.45±0.78 mg l⁻¹ had a significant effect on the TAN excretion rate, with pronounced ammonia uptake occurring for all animals at this concentration. The third study investigated the effects of body weight, diurnal rhythm, feeding and emersion on lobster oxygen consumption. Body weight was positively correlated to both standard and active oxygen consumption (mg O2 h⁻¹) while body weight was negatively correlated to mass-specific standard oxygen uptake (mg O2 g⁻¹ h⁻¹). Diurnal rhythm exhibited a strong effect on the lobsters oxygen consumption, with average night time values 67% greater than those recorded during the day. This was related to activity driven by intrinsic nocturnal foraging behaviour. Feeding resulted in a classic specific dynamic action (SDA) response, with postprandial oxygen consumption increasing to a peak before decreasing gradually to preprandial levels. Emersion resulted in a significant increase in oxygen consumption, with lobsters rapidly recovering to pre-emersion levels after four hours. Results from these studies suggest that the capture, transport and culture of juvenile P. h. rubellus is biologically feasible. Empirical data generated were used to provide recommendations regarding species optimised transport and culture protocols. A purge time of 48 hours before transport is suggested to ensure that ammonia excretion and oxygen consumption are at basal levels. Furthermore, emersed transport for a period of one hour is characterised by rapid recovery upon re-immersion. In order to prevent the accumulation of stressors, it is suggested that consecutive periods of emersion are interjected with recovery periods (five hours) in water to allow the removal of accumulated ammonia and repayment of the oxygen debt incurred. The recorded ammonia rates indicate that a biological filter size of 4.8 m³ is recommended for 1000 kg of fed lobsters in a culture situation, although this can be reduced considerably if lobsters are being held without feeding (0.72 m³). A flow rate of 112 l kg⁻¹ h⁻¹ is required to meet the metabolic requirements of lobsters. Bottlenecks to the viable commercial culture of P. h. rubellus, and the ability of this practice to provide the socio-economic benefits that were envisioned, are discussed.
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Dredge, Brendon Neville. "An assessment of the invasion state and fisheries suitability in four dams and a natural lake in the Western Cape, South Africa." Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/69114.
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Despite more than a century of introductions, fish invasions are poorly understood in South Africa. This thesis aims to: (1) provide baseline information on the fish fauna in five inland water bodies (four dams: Theewaterskloof, Clanwilliam, Quaggaskloof, and Voelvlei and a natural lake, Groenvlei) in the Western Cape; (2) determine which species were established and provide a baseline of abundance and size structure for monitoring and, (3) make preliminary recommendations for a fishery. First, criteria for determining establishment were developed by undertaking a full biological assessment of bluegill Lepomis macrochirus, a data-poor species in South Africa. This included the assessment of growth rate using validated estimates of age derived from otoliths in two dams (Clanwilliam Dam: Lt=335.9(1−eo.113(t+1.06)); Groenvlei: Lt=287.2(1-e−0.171(t+0.54)). Length at 50% maturity was similar for males (146 mmFL) and females (147 mmFL). Length frequency analysis combined with data on the age and growth and reproduction demonstrated that established populations of bluegill contained several age cohorts as well as mature and juvenile fishes. A meta-analysis was conducted to: (1) compile a list of initial stocking dates for all alien fishes in each waterbody and (2) use angler tournament data to assess for additional species and persistence over time. Data from the meta-analysis was combined with ichthyological survey data to determine establishment success. These data demonstrated that nine non-native species had established in the five water bodies. Clanwilliam Dam had the largest number (7) of non-native species established, Groenvlei (5) and Theewaterskloof, Brandvlei and Voelvlei the lowest with four species. The state of invasion of each species in the province showed that all nine species are categorised as invasive. This information on establishment was then integrated into a framework for rapidly determining what type of fishery would be most suitable for the 5 waterbodies. Potential yield was estimated using morphoedaphic models, were 260 t/yr for Theewaterskloof Dam, 93 t/yr for Voelvlei, 81 t/yr for Brandvlei, 59 t/yr for Groenvlei and 55 t/yr for Groenvlei. The CPUE for Groenvlei was the highest in gill nets with 1.32 ± 1.94 kg/h, then Voelvlei 1.05 ± 1.34 kg/h followed by Brandvlei (0.84 ± 1.48 kg/h), Clanwilliam (0.71 ± 1.55 kg/h) and lastly Theewaterskloof (0.36 ± 0.41 kg/h). Only Theewaterskloof could produce in excess of 100 t/yr but less than 400 t/yr of fish making it suitable for a small scale fishery. The CPUE values of Theewaterskloof were the lowest and a gill net fishery on this water body may not produce sufficient fish for the fishery. All water bodies had a high recreational angling usage, the opening of a small scale fishery could be detrimental to this industry. Subsistence and recreational anglers should be promoted with the possibility of a long line industry targeting Clarias gariepinus.
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Da, Silva Charlene. "The status and prognosis of the smoothhound shark (mustelus mustelus) fishery in the Southeastern and Southwestern Cape coasts, South Africa." Thesis, Rhodes University, 2008. http://hdl.handle.net/10962/d1003287.
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Global trends in commercially valuable teleost fisheries point to substantial deterioration in population size, offering limited potential for increased harvests. Consequently a shift in focus towards alternative fisheries has increased fishing effort towards targeting chondrichthyans as a possible solution to meet global demands. The life-history traits of chondrichthyans make them poor candidates for resolving economic and nutritional security as these make them particularly vulnerable to anthromorphic influences. Current fisheries management approaches based on centralized government intervention have proved inadequate. This failure of current management approaches is often linked with poor co-operation by industry with government when collecting fishery-dependent data. As management decisions are based on quantitative estimates from fishery assessment modes data collected are often of poor quality. Co-management with its implied power-sharing arrangement between government and fishing communities has been proposed as a more realistic alternative. The motivation within industry to collect high quality data can only be created with a feeling of ownership. The decline in linefish species in South Africa has led to increased exploitation of demersal sharks such as Mustelus mustelus. Their status as one of the target and by-catch species of South Africa's shark fisheries necessitated resource assessment. Age, growth, maturity and mortality calculations for M mustelus were made from data collected from 1983-2006. The maximum observed age for M mustelus was 25 years. Estimated von Bertalanffy growth parameters from observed length-at-age for combined sexes, females and males were L∞ = 1946.16 mm TL, K = 0.08 year⁻' , to = -3.63 year⁻'; L∞ = 2202.21mm, K = 0.05 year⁻', to = 4.67 years; and L∞ = 1713.19 mm TL, K = 0.08 year⁻' and to = -4.36 years, respectively. Instantaneous total mortality (Z) was estimated at 0.16 y⁻', whilst natural mortality (M) for M mustelus was estimated at 0.05 y⁻'. The age and length at 50% maturity was determined for combined sexes, females and males at 1216 mm TL corresponding to an age of 9.93 years, 1234 mm (TL) and 10.75 years, and 1106 mm TL and 9.1 years respectively. The smoothhound shark resource off the south-eastern and south-western Cape coast was assessed by three dynamic pool models; yield per recruit, spawner biomass per recruit and an extended yield and spawner biomass per recruit. Due to the longevity of elasmobranches the per-recruit model was extended over a 20 year time-frame to simulate resource responses to management options. Fo.1 was estimated as 0.034 year⁻' and F MAX was estimated as 0.045 year⁻'. FsB50 was estimated as 0.031. The extended per-recruit model tested the outcome of different management scenarios, Size and effort control showed the least probability of pristine biomass falling below 20% of current levels in 20 years (where selectivity was set at 3 years). The replacement yield model showed that the average catches over the past decade are 2.5 times higher than the replacement yield is on the South Coast and 1.30 on the West Coast. A more realistic level optimising yield would be at 0.05 with a selection pattern at 3 years, where the probability of the biomass falling to below 20% of pristine pre-exploited levels in twenty years becomes negligible. A comparison of the models showed that current catches need to be halved for exploitation of smoothhound sharks to be sustainable. The results of this study indicate a need for a management intervention for M mustelus in South Africa with regards to potential overexploitation and collection of quality data for further assessments. A demersal identification key was developed as part of this study, which should aid monitoring officials in accurately identifying shark logs for collecting data. This study showed how adopting a management plan with the inclusion of comanagement concepts would improve the quality of data collected and increase monitoring of fishing activities. The inclusion of co-management is possible due to the unique bottle neck created by few demersal shark processing facilities actively exporting shark. A fishery management plan was compiled proposing several management options including size and effort controls.
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Dicken, Matthew Laurence. "Population dynamics of the raggedtooth shark (Carcharias taurus) along the east coast of South Africa." Thesis, Connect to this title online, 2006. http://eprints.ru.ac.za/247/.
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Mubaiwa, Pasipanodya. "Assessing the role played by informal traders within the snoek value chain in selected townships in Cape Town, South Africa." University of the Western Cape, 2014. http://hdl.handle.net/11394/4219.
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Magister Philosophiae (Land and Agrarian Studies) - MPhil(LAS)In the Western Cape, snoek (Thyrsites atun) is a target for small scale fisheries. This fishery is comprised of recreational, subsistence and traditional line fisheries in the province. Snoek contributes 40% to 50% of the line fish which is landed. This thesis sought to identify the roles which are performed by informal snoek traders in certain Cape Town coloured1 townships in the snoek value chain. There are various aspects of this fish which heightens its importance in the Western Cape. Snoek is significant in the provision of food security for many poor and working class individuals and households within the coloured townships of Cape Town. Snoek is an omega 3-rich fish and is one of the Cape’s most well-known gastronomic traditions. It provides affordable and easily absorbable proteins, vitamins and minerals for township people. Poor people mostly rely on starches and fail to afford the most expensive protein sources like red meat. The snoek trade also helps in the creation of jobs and enables people to earn cash income. The study revealed that there is specialisation and division of labour between snoek traders and fishers. Snoek is sold via the auction system at the various landing zones scattered all over the Western Cape. It was observed that the snoek value chain is dominated by men and there are few women in the value chain who sell or clean snoek. Informal snoek traders ply their business next to shops or on the sides of busy roads using ‘bakkies’2 from where the fish is flayed and sold to the waiting customer to emphasise its freshness. Snoek traders create convenience by bringing fresh fish to customers in the townships. They also assume risks which come with venturing in business. Some snoek traders engage in multiple livelihood strategies by diversifying income generating activities rather than relying on one income source. Among the several challenges which snoek traders confront, one pressing challenge they need to address is their lack of organisation which prohibits them from speaking with one voice. The snoek value chain should be more efficient so that it keeps supplying the much needed nutrients in the townships. Both primary and secondary data collection techniques were used. Snoek traders face a myriad of challenges which require the authorities to address. They have no access to infrastructure with sanitary facilities. The other problem they face is that they are disorganised amongst themselves which weaken their cause. Traders and fishers would like to see the real transformation taking place within this snoek fishery. Traders are convinced that there is corruption within the fisheries department and many have lost faith in the system.
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Booth, Anthony John. "Biology, stock assessment and management of the panga Pterogymnus laniarius on the Agulhas Bank, South Africa." Thesis, Rhodes University, 1998. http://hdl.handle.net/10962/d1005085.
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The panga, Pterogymnus laniarius (Cuvier, 1830), is a South African endemic sparid fish species. On the Agulhas Bank, South Africa it is a commercially important species, caught as bycatch in the hake directed trawlfisheries and targeted by offshore hook-and-linefishers. Recently there has been considerable interest shown in directing further fishing effort on this species. The lack of a suitable management procedure for teleost bycatch in South Africa was the principal reason for undertaking this study. This thesis investigates aspects the panga's life history, particularly those aspects that have management implications. A full knowledge of this species' distribution and abundance was necessary as this could highlight the existence of any nursery areas, ontogenetic migratory patterns and areas of high spawner biomass. The derived parameter estimates were then included as inputs into stock assessment models to determine the status and productivity of the resource. Growth studies based on sectioned sagittal otoliths revealed that the panga was a relatively slow growing fish with ages of 16 years being recorded. Growth was best described by the von Bertalanffy growth model as Lt=379.4(1-e⁻°·¹³⁽t ⁺ ¹·⁷⁸⁾). Total, natural and fishing mortalities were estimated at 0.36 year⁻¹, 0.28 year⁻¹ and 0.08 year ⁻¹, respectively. Detailed histological examination of the gonads revealed that panga is a late gonochorist, males and females maturing after a non-functional intersexual stage. Females mature at approximately 200 mm fork length or 4 years of age. Reproduction occurs throughout the year although there is a slight peak in winter. Gametogenesis was found to be similar to that of other sparid fishes and marine teleosts in general. The panga feeds predominantly on crustaceans with a distinct ontogenetic shift in feeding habits. Juvenile fish feed predominantly in the water column on mysids after which they move to the benthos. Subadult fish feed principally on ophiuroids and amphipods. Adult fish remain on or near the benthos, feeding predominantly on crabs, and on polychaetes, ophiuroids and fishes to a lesser extent. Several aspects of the panga's biology contribute to its ability to sustain a higher fishing pressure than other sympatric sparid species. These include its late gonochoristic reproductive style, protracted spawning season, maturation before recruitment and preference for soft substratum prey that enables it to utilise large areas of the Agulhas Bank. The panga's longevity, slow growth and low natural mortality rate, however, mitigated against these factors and were considered in the stock assessments. A heterogeneous Geographical Information System (GIS) was developed to analyse the distribution and abundance patterns of the panga. The GIS developed in this thesis makes a significant contribution towards the development of a South African Fisheries Information System to analyse and manage fish resources in general and bycatch resources in particular. The GIS developed in this study combines statistical Generalized Additive Modelling and standard GIS methods. Analysis of fourteen biannual fishery independent biomass surveys, disaggregated by life history stage, revealed that a nursery area for immature fish (<23 cm TL or < 4 years of age) exists on the Central Agulhas Bank. After sexual maturation, approximately 40% of the biomass migrated eastwards, colonising large areas of the Eastern Agulhas Bank.ilie location of the nursery area appears to be a result of the pelagic eggs and larvae being advected towards the coast in an anti-cyclonic gyre, stemming off the Agulhas current and later deposited over the Central Agulhas Bank. The weak bottom currents on the Central Agulhas Bank prevented juvenile loss to the Benguela system. The eurytopy of adult fish to various physical variables such as temperature, dissolved oxygen and stronger currents enabled it to reduce conspecific competition and migrate eastwards with distribution primarily determined by depth. Relative biomass estimates revealed a gradual increase in biomass of 5.5% per annum between 1988 and 1995. Predictions from yield-per-recruit, biomass-per-recruit and spawner biomass-per-recruit analyses showed that there was scope for further exploitation. A FSB₅₀ fishing strategy was considered to be the most appropriate fishing strategy as it did not reduce the spawner biomass-per-recruit to less than 50% of unexploited levels. Effort control was considered the most effective management tool as the age-at-50%-selectivity occurred after age-at-sexual maturity and releasing undersized fish was undesirable due to heavy mortalities resulting from severe barotrauma. The panga resource was also assessed using an age-structured production model. The values for the free parameters of the model were estimated using biomass indices derived from fishery-independent trawl surveys. Although the data were fairly uninformative about the productivity of the resource, the results indicated robustly, that the population has recovered from low levels in the mid-1970's and could sustain higher levels of fishing intensity. Risk analysis calculations were used to assess the sustainability of different catch scenarios. The level of sustainable catch was found to be sensitive to the selectivity pattern of the gear utilised. Both stock assessment methods used in this study to investigate the status of the panga resource showed that the resource could theoretically sustain higher catches. It was found that although the stock could be harvested using available fishing methods, the sympatry of this species with other commercial species was of concern as the latter would form a significant bycatch in a panga directed fishery. The failure of current harvesting methods to address the bycatch problem highlights the management problem in South Africa and stresses the need for creativity by both scientists and fishers in designing new and improved methods for selectively harvesting bycatch fish resources. Considering that no suitable method is currently available to fish the panga stock in a directed fishery the fishery should be managed as status quo until some suitable and efficient gear is developed.
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Ketse, Noziphiwo. "The effects of selected reference toxicants on embryonic development of the freshwater shrimp caridina nilotica (Decapoda: Atyidae)." Thesis, Rhodes University, 2007. http://hdl.handle.net/10962/d1005367.
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Aquatic toxicity tests are increasingly being used in water resource management worldwide, and currently in South Africa, policy and legislation are being drafted to reflect this international trend. While standard toxicity test methods and test organisms are being considered to develop and set water quality guidelines and effluent discharge limits, it is not clear whether guidelines and discharge limits set using these standard test organisms will be sufficient to protect South Africa’s scarce water resources. As part of ongoing research to investigate the use of indigenous riverine organisms as toxicity test organisms a number of potential species have been identified, including the freshwater shrimp Caridina nilotica. For much of the history of aquatic toxicological data the bulk of the data has been generated by acute toxicity testing, based on short exposures and using mortality as the response end point. There are relatively few chronic, longterm tests with sub-lethal endpoints. However, it was recognized that information about longer exposure durations and non lethal response endpoints was needed, instead of mortality. Chronic tests can provide a more environmentally realistic measure of chemical toxicity than acute toxicity tests. Caridina nilotica has been identified as a potential standard toxicity test organism, as it is widely distributed, easy to find and it occurs in flowing waters. It is an indigenous species which can be easily cultured and maintained in the laboratory and is also ecologically important. Both adults and juveniles have been used successfully in acute toxicity tests at the Institute for Water Research (Rhodes University) and the ability to rear the organisms under laboratory conditions has allowed the development of chronic toxicity tests using C. nilotica. Chronic early life stage tests include continuous exposure of the early life stages, which are presumed to be the most sensitive for aquatic organisms. This study reports on the embryonic development of C. nilotica at the culture temperature of 24⁰C. Morphological developmental stages were monitored and measured and 7 developmental stages were identified. Based on the measurements of the features that were identified, toxicity tests using the reference chemicals sodium chloride (NaCl), sodium sulphate (Na₂SO₄) and cadmium chloride (CdCl₂) were undertaken to test the suitability of C. nilotica embryonic development for chronic toxicity tests for use in water resource management. The length, width, length:width ratios and area of the features decreased in size when exposed to the chemicals. The Lowest Observed Effect Concentration (LOEC) values were 2000mg/L for Na₂SO₄, 3000mg/L for NaCl and 0.31mg/L for CdCl₂. The No Observed Effect Concentration (NOEC) values were 1000mg/L for Na₂SO₄, 2000mg/L for NaCl and <0.31mg/L for CdCl₂. Further research on the teratogenic effects of single chemicals and industrial effluent on developing C. nilotica embryos needs to be undertaken in order to evaluate the described test protocol for use in water resource management.
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Mackenzie, Bernard Louis. "An assessment of the shore baitfishery in the Eastern Cape." Thesis, Rhodes University, 2005. http://eprints.ru.ac.za/165/.
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Sunde, Jacqueline. "Customary governance and expressions of living customary law at Dwesa-Cwebe: contributions to small-scale fisheries governance in South Africa." Doctoral thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/13275.
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Includes bibliographical references.Customary systems of marine resource governance have gained increasing attention internationally in the past three decades. Notwithstanding this, and despite the Constitutional recognition of customary governance and customary law in South Africa, the post-apartheid legislative reforms in the fisheries sector have failed to recognise customary systems of marine resource governance. Drawing on a case-study of the Dwesa-Cwebe community in the Eastern Cape, South Africa, this research aimed to describe and understand the customary marine resource governance system of this community and its relationship to living customary law. It explores how this customary system of marine resource governance has interfaced with statutory and other systems of law in the past and how it continues to develop in the current context. The findings from this research highlight the distinctive nature of the customary system of marine resource governance practiced by the community of Dwesa-Cwebe and their expressions of living customary law embedded in this governance system. The nature of this system is foundationally different to that of a Western statutory governance system. This customary system of governance has interacted with the statutory system for over a century, in part distorted by this system but retaining its integrity. In the context of the Constitutional recognition of customary systems of governance and customary law, this governance system now requires understanding and recognition in a new system of marine resource governance in South Africa. This thesis explores the contribution that this system of customary governance can make towards promoting socially just smallscale fisheries in South Africa. It argues that harmonisation of the statutory and customary system of marine resource governance demands an approach to governance theory and practice that is able to imagine an alternative ‘ecology of governance’.
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Hutchings, Kenneth. "Catch, effort and socio-economic characteristics of the gill and beach-seine net fisheries in the Western Cape, South Africa." Master's thesis, University of Cape Town, 2000. http://hdl.handle.net/11427/6271.
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Bibliography: leaves 134-143.This study was conducted with the overall objective of providing scientific infonnation relevant to the management of the gill and beach-seine net fisheries, particularly with respect to decisions about increased participation in the fisheries. Its primary aims were to provide quantitative estimates of total catch and effort, to assess the current and potential future importance of by-catch in the fisheries, to describe the socio-economic status of participants and to evaluate the management measures currently in effect.
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Mwanja, Wilson Waiswa. "Genetic biodiversity and evolution of two principal fisheries species groups, the Labeine and Tilapiine, of Lake Victoria region, East Africa /." The Ohio State University, 2000. http://rave.ohiolink.edu/etdc/view?acc_num=osu1488194825666344.
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Gatonye, Margaret. "Social Inclusivity and Equitable Development: Women in Fisheries and Aquaculture in Rural Communities of Kenya." Ohio University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1586540674871228.
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McCord, Meaghen Erica. "Aspects of the ecology and management of the Soupfin shark (Galeorhinus galeus) in South Africa." Thesis, Rhodes University, 2005. http://hdl.handle.net/10962/d1005066.
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Global trends in teleost fisheries indicate significant population declines. Thus, alternative fisheries are being developed to meet the growing economic and nutritional demands of the expanding human population. Recently, it has been established that elasmobranch fisheries may fulfill these demands. As many elasmobranchs possess life-history characteristics that make them particularly vulnerable to overfishing, it is imperative to develop management strategies prior to the inception of these fisheries to ensure sustainable resource utilisation. In South Africa, elasmobranchs have been commercially exploited since the 1930s. Although generally considered an under-exploited resource, the potential for growth within these fisheries has been recognized. In 2005, the commercial shark fishery will undergo a transition from medium to long-term rights allocations. This represents an ideal opportunity for scientists and managers to develop precautionary species-specific management plans for commercially exploitable elasmobranch species. The soupfin shark (Galeorhinus galeus) is one of the principal target species in South Africa’s shark fisheries. Given its inherent susceptibility to overexploitation, G. galeus was selected as a management priority by South Africa’s regional fisheries organisation. The purpose of this study was to examine and describe the stock status of G. galeus in South Africa, and to develop a precautionary fishery management plan to ensure the sustainability of this resource. Age, growth, and mortality calculations for G. galeus were made from research survey data collected between 1996 and 1999. A small sample size precluded independent analyses of females. The maximum recorded age for G. galeus was 33 years. Estimated von Bertalanffy growth parameters from observed length-at-age for males and combined sexes were: L∞ 1542.8 mm TL, K 0.21 year⁻¹ , t₀ -2.79 year⁻¹ and L∞ 1560.3 mm TL, K 0.19 year¹, t₀ -3.03 year⁻¹, respectively. The age-at-50% maturity was determined to be 6 years, corresponding to 1011 mm TL for males and 1100 mm TL for combined sexes. Natural mortality was calculated as 0.126 yr⁻¹. The rate of instantaneous total mortality was calculated as 0.27 yr⁻¹. Catch trend analysis showed that catches and CPUE of G. galeus are increasing in the demersal longline fishery, and decreasing in the handline fishery. Decreasing catches and CPUE were observed in fishery-independent research survey data. The status of the soupfin shark stock was modelled using per-recruit analysis. The SB/R model indicated the soupfin shark is being optimally exploited and spawner biomass is at 43% of preexploitation levels. Current fishing levels ( F = 0.14 yr⁻¹) approximate the Fsb₄₀ level (F = 0.17 yr¹); thus, an increase in fishing pressure may lead to stock collapse. It was determined that the current age-at-capture (7.9 years) should be increased to 10 years, or 1420 mm TL, to maximize yield and minimize the possibility of recruitment failure. The results of this study indicate a need for immediate scientific and management intervention in South Africa’s soupfin shark fishery. An assessment report and fishery management plan for G. galeus was compiled, and several management options were proposed. These include the implementation of licence and size restrictions, as well as seasonal/area closures. The potential for an experimental gillnet fishery should be investigated.
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Nicholson, Gareth Hurst. "Towards understanding the effects of stocking density on farmed South African abalone, Haliotis Midae." Thesis, Rhodes University, 2014. http://hdl.handle.net/10962/d1015646.
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The profitability of abalone farms is heavily influenced by their production per unit of grow-out space. With farms having physically expanded to the maximum, and with increasing production costs, one of the most realistic ways for farms to increase their production is through optimizing stocking densities. The effect of stocking density on Haliotis midae performance is undocumented and optimal stocking densities for this species have not been determined. Experiments were conducted under farm conditions to investigate the effects of four different stocking densities (16 %, 20 %, 22 % and 24 % of available surface area) on growth, production and health of three different size classes of abalone (15-35 g, 45-65 g, and 70-90 g start weight). Each treatment was replicated four times and trials ran over a period of eight months with measurements being made at four month intervals. Abalone behaviour was observed during the trials in the experimental tanks. Weight gain per abalone decreased with an increase in density for all tested size classes (5.04 ± 0.18 to 2.38 ± 0.17; 5.35 ± 0.21 to 4.62 ± 0.29; 7.97 ± 0.37 to 6.53 ± 0.28 g.abalone-1.month-1 for the 15-35, 45-65 and 70-90 g classes respectively, with an increased density of 16 to 24 %). Individual weight gain of 15-35 g abalone was similar at stocking densities of 16 % and 20 % while weight gain of 45-65 g and 70-90 g abalone decreased when density was increased above 16 %. Biomass gain (kg.basket-1.month-1) was not affected by stocking density in the 15-35 g and 45-65 g size classes (1.29 ± 0.02 and 0.97 ± 0.02 kg.basket-1.month-1 respectively). However, the biomass gained by baskets stocked with 70-90 g abalone increased with stocking density (1.08 ± 0.02 to 1.33 ± 0.02 kg.basket-1.month-1) with an increased density of 16 to 24 %) and did not appear to plateau within the tested density range (16 to 24 %). Food conversion ratio did not differ significantly between densities across all size classes. Stocking density did not have a significant effect on abalone condition factor or health indices. The proportion of abalone above the level of the feeder plate increased with density (7.26 ± 1.33 to 16.44 ± 1.33 with an increased density of 16 to 24 %). As a proportion of abalone situated in the area of the basket, the same proportions were situated on the walls above the feeder plate and on the feeder plate itself irrespective of stocking density (p > 0.05). Higher proportions of animals had restricted access to feed at higher stocking densities (p = 0.03). The amount of formulated feed available on the feeder plate did not differ between stocking densities throughout the night (p = 0.19). Individual abalone spent more time above the feeder plate at higher stocking densities (p < 0.05). The percentage of time above the feeder plate, spent on the walls of the basket and on the feeding surface was not significantly different at densities of 20 %, 22 % and 24 % (p > 0.05) but abalone stocked at 16 % spent a greater percentage of time above the feeder plate on the feeding surface (83.99 ± 6.26 %) than on the basket walls (16.01 ± 6.26 %). Stocking density did not affect the positioning of abalone within a basket during the day or at night. Different size H. midae are affected differently by increases in stocking density in terms of growth performance. Findings from this research may be implemented into farm management strategies to best suit production goals, whether in terms of biomass production or individual weight gain. The fundamental mechanisms resulting in reduced growth at higher densities are not well understood, however results from behaviour observations suggest that competition for preferred attachment space and feed availability are contributing to decreased growth rates. With knowledge of abalone behaviour at different densities, innovative tank designs may be established in order to counter the reduction in growth at higher densities.
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Turay, Foday. "An economic analysis of artisanal fisheries management alternatives in west Africa : the case of the marine pelagic fishery in Sierra Leone." Thesis, University of Portsmouth, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.306941.
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