Abalone poaching is a major problem in South Africa. The South African abalone, Haliotis midae, rates as an extreme example of high levels of illegal harvesting. The research aimed at examining the role of the different role players in preventing poaching of the species in the East London area of the Eastern Cape Province of South Africa and determining the challenges the officers faced as there was an increase in poaching in the area. To achieve this aim, the research techniques including questionnaires, interviews and focus groups were used. Fisheries compliance and enforcement faces challenges of the illegal harvesting of abalone since 1994. In the past 18 years (1994-2012), and more specifically in the past nine years (2004-2012), poaching of abalone has increased at an alarming rate along the East London coastline. The failure of the state to issue fishing rights and conduct effective sea-based compliance, combined with the incentives to fish abalone created the conditions for rapid emergence of illegal harvesting. The uncontrolled fishing had a dramatic effect on the stock, and the average size of abalone decreased significantly. The Eastern Cape Province abalone cultivation industries were developed due to the decline in harvesting of abalone. Government departments such as the Department of Agriculture, Forestry and Fisheries; the Department of Economic Development, Environmental Affairs and Tourism; the South African Police Services together with the Eastern Cape Parks and Tourism Agency have conducted joint operations to combat the illegal harvesting of abalone. These operations have led to many arrests of abalone poachers along the East London coastline. The quantity of confiscated abalone has increased from 2007 to 2011. The positive results achieved by the departments during joint operations showcase robust efforts to eradicate the environmental transgression in the East London Coastline. Joint operations are encouraged by all the departments to save the species for future generations. Workshops involving different stakeholders had to take place and the policies in place must have a bottom-up approach where communities are involved.

ENGLISH ABSTRACT: The first successful captive spawning of the South African abalone Haliotis midae occurred in the 1980’s and subsequently the commercial abalone industry in South Africa has developed, with an estimated investment of US$ 12 million and annual output of 500 to 800 tons by 2001, making South Africa the biggest abalone producer outside of Asia. Natural kelp is currently the major feed and the development of a suitable substitute, and improved disease management in abalone culture are seen as the primary factors limiting expansion of the industry in South Africa. Further, abalone growth rates are very slow and improvements in growth rate will lead to shortened production times with benefits to producers. Diseases in aquaculture have traditionally been combated using antibiotics as treatment (therapeutic usage) and preventative measure (prophylactic usage). In terrestrial livestock management, antibiotics are also used as growth promoters. The use of antibiotics in aquaculture has recently sparked concerns about the development of antibiotic resistance in pathogens of humans and aquaculture organisms, and alternative strategies to using antibiotics mainly focus on manipulating the microbial composition in the host organism, in order to establish a beneficial microbial population to prevent disease. The role that organic acids and their salts can play as growth promoters in the South African abalone Haliotis midae, and as manipulators of the gut microflora of this species of abalone was investigated and compared to the effects of antibiotics. Three different treatments were tested against a negative control and a positive control containing 30ppm avilamycin, a commercial antibiotic growth promoter (AGP) used in the pig and poultry industry. The 3 treatments consisted of 1% acetic and 1% formic acid (treatment AF), 1% sodium benzoate and 1% potassium sorbate (treatment SBPS), and 1% benzoic and 1% sorbic acid (treatment BS). Three different experiments were conducted to test the effects of the different acids and salts. The first experiment was under controlled optimum water temperature conditions (16.5ºC), another at elevated water temperature (20.5ºC) in order to test response during temperature stress conditions, and the final trial was conducted under uncontrolled practical production conditions. In an attempt to establish the mechanism by which the treatments have their effects (if any), the composition of the gut microflora of the abalone was monitored. It was found that the organic acids and salts investigated can enhance the growth rate of Haliotis midae in the size class 23 mm to 33 mm mean length significantly when compared to both control treatments. It was further found that the tested AGP had no effect on growth rate. None of the treatments had a significant effect on feed conversion ratio (FCR), Incidence cost (IC) or feed intake. It could also not be shown that the treatments affected the intestinal microflora of the abalone, although this might be due to inadequate microbiological methods. The mechanism by which the acids and salts have their effects could not be established. It was found that the animals in the controlled system underwent an initial adaptation period, which led to improvement in specific growth rate (SGR), FCR and IC as the experiment progressed during the controlled optimal conditions experiment. Large differences in FCR and IC was seen for controlled optimal conditions and production conditions which means that there is still a large scope for developing methods to improve practical on-farm feed utilisation by abalone. SGR, FCR and IC were negatively influenced by raising water temperature from 16.5ºC to 20.5ºC. The composition of the gut microflora of the abalone also changed significantly after the water temperature was raised. It appears that animal weight gain and shell growth respond differently to changing water temperatures, which is reflected in a change in Fulton condition factor. A relationship between the length and weight of abalone between 15 mm and 47 mm was established and it was found that Haliotis midae does not follow an isometric growth relationship. This relation can be used as a tool to improve farm management and therefore also profitability. Various micro-organisms were isolated from Haliotis midae during the trial, but their relationship and interaction with abalone is not clear. Clear dominance by specific species of bacteria was observed during certain periods. The current research has clearly showed the potential of organic acids and their salts to act as growth promoters in the South African abalone Haliotis midae, with application in both the local aquaculture and feed manufacturing industries. The possibility further exists that some aspects of the current research can be adapted to be applicable in other abalone species and even in other aquaculture species. / AFRIKAANSE OPSOMMING: Die eerste suksesvolle aanteel van die Suid-Afrikaanse perlemoen Haliotis midae in gevangeskap is in die 1980’s gerapporteer, waarna ‘n suksesvolle akwakultuur industrie ontwikkel het met ‘n geskatte produksievermoë van 500 tot 800 ton en kapitaalbelegging van US$ 12 miljoen in 2001. Suid-Afrika is tans die grootste perlemoen-produserende land wat buite Asië geleë is. Die ontwikkeling van ‘n geskikte alternatiewe voedselbron vir natuurlike kelp (tans die algemeenste voedselbron wat gebruik word in die kweek van perlemoen), sowel as verbeterde siektebestryding word tans gesien as die hooffaktore wat verdere uitbreiding in die Suid-Afrikaanse industrie beperk. Perlemoen het verder baie stadige groeitempo’s en enige verbetering in hierdie verband sal produksietye verkort en dus produsente bevoordeel. Siektes in akwakultuur word tradisioneel bestry deur gebruik te maak van antibiotiese behandeling (terapeutiese bestryding) of van voorkomende behandeling (profilaktiese bestryding). In gewone diereproduksie-sisteme (bv. varke en hoenders) word antibiotika ook gebruik as groeistimulante. Die gebruik van antibiotika in akwakultuur het onlangs die bekommernis laat ontstaan dat sekere menslike en dierepatogene weerstand kan ontwikkel teen sommige middels, wat die behoefte laat ontstaan het om siektebestryding sonder die gebruik van antibiotika te ontwikkel. Alternatiewe strategieë fokus grootliks daarop om die samestelling van die mikrobiese bevolking van die gasheer te manipuleer en sodoende ‘n voordelige bevolking in die gasheer te vestig, wat dan siektes voorkom. Daar is ondersoek ingestel na die rol van organiese sure en hul soute as groeistimulante en manipuleerders van die mikrobiese bevolking in die Suid-Afrikaanse perlemoen Haliotis midae. Drie verskillende behandelings is getoets en vergelyk met beide ‘n negatiewe- en positiewe kontrole (wat 30 dele per miljoen van ‘n kommersiële antibiotiese groeistimulant bevat het). Die drie formulasies het onderskeidelik bestaan uit ‘n mengsel van 1% etanoëen 1% metanoësuur (behandeling AF), 1% bensoë- en 1% sorbiensuur (behandeling BS) en 1% natriumbensoaat en 1% kaliumsorbaat (behandeling SBPS). Om die effekte van hierdie formulasies te toets, is daar 3 proewe gedoen. Een proef is gedoen onder temperatuurbeheerde toestande teen ‘n optimum watertemperatuur van 16.5ºC terwyl ‘n ander gedoen is onder onbeheerde, praktiese produksie-omstandighede. ‘n Verdere beheerde proef is gedoen teen ‘n watertemperatuur van 20.5ºC om die effek van die verskillende formulasies te toets wanneer die diere aan temperatuur-spanning blootgestel word. Die samestelling van die mikrobiese bevolking in die dunderm van die perlemoen is deurentyd gemonitor in ‘n poging om die meganisme vas te stel waarvolgens die sure en soute hul effek het, indien daar enige effek waargeneem word. Daar is gevind dat die onderskeie sure en suursoute die groeitempo van Haliotis midae met ‘n gemiddelde lengte van 23 mm tot 33 mm beduidend kan verhoog in vergelyking met die groeitempo’s van beide kontroles. Daar is gevind dat die antibiotiese groeistimulant geen effek het op die groei van die diere nie en dat geen behandelings ‘n beduidende effek op voeromsetting, voerkoste of voerinname gehad het nie. Daar kon nie bewys word dat enige van die formulasies of die antibiotika ‘n effek gehad het op die mikrobes in die spysverteringskanaal van die perlemoene in die sisteem nie, alhoewel die gebrek aan ‘n effek moontlik toegeskryf kan word aan die onakkurate en onvoldoende mikrobiologiese metodes wat gebruik is tydens die studie. Die meganisme waarvolgens die sure werk kon nie vasgestel word nie. Daar is verder gevind dat die diere in die temperatuur-beheerde eksperiment aanvaklik deur ‘n aanpassingsperiode gegaan het, wat tot gevolg gehad het dat die spesifieke groeitempo, voeromsetting en voerkoste verbeter het met die verloop van die eksperiment. Daar is groot verskille gevind in die voeromsetting van beheerde optimale toestande en onbeheerde produksietoestande, wat impliseer dat daar nog baie ruimte en geleenthede is om metodes te ontwikkel wat beter voeromsetting bewerkstellig tydens perlemoenproduksie. Spesifieke groeitempo, voeromsetting en voerkoste is nadelig beïnvloed toe die watertemperatuur verhoog is vanaf 16.5ºC na 20.5ºC. Die samestelling van die mikrobiese bevolking in die spysverteringskanaal van die perlemoen het ook beduidende veranderinge ondergaan tydens hierdie temperatuur verhoging. Dit wil voorkom asof die lengtegroei van die dop en die toename in massa verskillend reageer op ‘n verandering in watertemperatuur en hierdie effek word weerspieël in die verandering in Fulton-kondisiefaktor. ‘n Verwantskap tussen totale doplengte en totale gewig van Haliotis midae kon vasgestel word vir diere tussen 15 mm en 47 mm en daar is gewys dat H. midae nie ‘n isometriese groeipatroon volg nie. Hierdie verwantskap kan aangewend word tydens produksiebestuur om produksie te verbeter en daardeur ook winsgewendheid te verhoog. Verskeie mikrobes is tydens die verloop van die proef geïsoleer, maar die rol van en interaksie tussen hierdie mikrobes en die Suid-Afrikaanse perlemoen is nie duidelik nie. Sekere bakterieë het die mikrobiese bevolking in die spysverteringskanaal van die perlemoen in hierdie proef oorheers tydens sekere groeiperiodes. Die huidige navorsing het duidelik aangetoon dat organiese sure en hul soute as groeistimulante kan optree in die Suid-Afrikaanse perlemoen Haliotis midae, met toepassings in die plaaslike akwakultuur- en voervervaardigins-industrieë. Dit beskik verder oor die potensiaal om aangepas te word sodat dit toepaslik is in ander perlemoenspesies en selfs ander akwakultuur organismes.

Thesis (PhD (Genetics))--University of Stellenbosch, 2009. / ENGLISH ABSTRACT: South African abalone, Haliotis midae, has been the subject of major concern regarding its survival and conservation over the last decade or more. Being the only one of five endemic species with commercial value, there is considerable interest and urgency in genetic management and improvement of this species. Limited genetic information and the increasing conservation concern of this species are considered the key motivations for generating information on the micro- and macro-evolutionary processes of H. midae, the overall objective of this study. This study reported the first microsatellite and Single Nucleotide Polymorphism (SNP) markers developed specifically for Haliotis midae. Both these marker types were applied to elucidate the degree of gene flow in nine natural abalone populations whilst testing for two contrasting hypotheses; panmixia versus restricted gene flow. Data was analysed using a series of methodological approaches ranging from traditional summary statistics to more advanced MCMC based Bayesian clustering methods with and without including spatial information. Using only microsatellite data, the historical demography of the species was also examined in terms of effective population size and population size fluctuations. Finally, the evolutionary positioning and origin of Haliotis midae with regards to other Haliotis species was investigated based on mitochondrial and nuclear sequence data. Both microsatellite and SNP data gave evidence for subtle differentiation between West and East coast populations that correlates with a hydrogeographic barrier in the vicinity of Cape Agulhas. Population substructure was supported by AMOVA, FCA and Bayesian clustering analysis. Clustering utilizing spatial information further indicated clinal variation on both sides of the proposed barrier with a region in the middle coinciding with a secondary contact zone, indicating possible historical isolation during glacial periods. Overall, the similar degree of substructure observed with both microsatellites and SNPs supported the existence of contemporary and/or historical factors with genome-wide effect on gene flow. The population expansion measured with the microsatellites was inconsistent with the known recent decline but taking the species’ life cycle and large effective population size into account, a shrinkage in population size will probably only be apparent in a few generations time. On a macro-evolutionary scale, this study presents the first classification of South African abalone as a monophyletic group within the Haliotidae family. The topology based on the combined mitochondrial and nuclear dataset is highly suggestive of a relatively recent radiation of the SA species from the Indo-Pacific basin. The study concludes by describing the most likely factors that could have affected overall population structure and makes suggestions on how the given genetic information should be incorporated into strategies aimed towards the effective management and conservation of Haliotis midae. / AFRIKAANSE OPSOMMING: Die Suid-Afrikaanse perlemoen, Haliotis midae, is oor die laaste dekade of meer die onderwerp van groot bekommernis betreffende die spesie se oorlewing en bewaring. Aangesien dit die enigste van vyf endemiese SA spesies is met kommersiёle waarde, is daar besonderse belang en erns in die genetiese beheer en verbetering van die spesie. Beperkte genetiese inligting en ‘n toenemende behoefte om die spesie te bewaar is die hoof motivering agter die generering van informasie rakende mikro- en makro-evolusionêre prosesse in Haliotis midae en is die oorhoofse doel van hierdie studie. Hierdie studie beskryf die eerste mikrosatelliete en enkel basispaar polimorfismes wat ontwikkel is spesifiek vir Haliotis midae. Beide tipe merkers is aangewend om die mate van gene vloei in nege wilde perlemoen populasies te ondersoek terwyl twee hipoteses ondersoek is; panmiksie versus beperkte gene vloei. Data is geanaliseer deur gebruik te maak van ‘n reeks metodieke benaderings wat wissel van tradisionele opsommings statistieke tot meer gevorderde MCMC gebasseerde groeperings metodes met of sonder die gebruik van geografiese data. Mikrosatelliet data is ook aangewend om die historiese demografie van die spesie te bepaal in terme van effektiewe populasie grootte asook veranderinge in populasie groottes. Laastens is die evolusionêre posisionering en oorsprong van Haliotis midae teenoor ander Haliotis spesies ondersoek deur gebruik te maak van mitokondriale en nukleêre DNA volgorde data. Beide mikrosatelliet en enkel basispaar polimorfisme data lewer bewys van ‘n subtiele genetiese verskil tussen wes en ooskus populasies wat verband hou met ‘n hidrografiese skeiding in die omgewing van Kaap Agulhas. Populasie struktuur is ondersteun deur die analise van molekulêre variansie (AMOVA), faktoriale komponente analise asook Bayesiese groeperings analise. Groeperings analise wat geografiese informasie insluit dui klinale genetiese variasie aan beide kante van die skeiding aan met ‘n area in die middel wat ooreenstem met ‘n sekondêre kontak gebied. In totaal, ondersteun die soortgelyke mate van struktuur verkry met beide die mikrosatelliete en enkel basispaar polimorfismes die bestaan van hedendaagse en/of historiese faktore met genoom wye invloed op gene vloei. Die toename in populasie grootte vasgestel deur die mikrosatelliet data stem nie ooreen met die onlangse afname waargeneem in die spesie nie, maar met inagneming van Haliotis midae se lewenssiklus en groot effektiewe populasie grootte, sal die afname in populasie grootte moontlik eers oor ‘n paar generasies na vore kom. Op ‘n makro-evolusionêre skaal lewer hierdie studie die eerste klassifikasie van Suid-Afrikaanse perlemoen as ‘n monofiletiese groep binne die Haliotidae familie. Die topologie gebaseer op ‘n gesamentlike mitkondriale en nukleêre datastel is hoogs aanduidend van ‘n relatiewe onlangse verspreiding van die Suid-Afrikaanse spesies uit die Stille-Indiese Oseaan. Die studie sluit af deur die mees algemene faktore te bespreek wat populasie struktuur kon beïnvloed het en maak voorstelle op watter wyse hierdie genetiese inligting aangewend kan word vir die effekiewe beheer en bewaring van Haliotis midae.

Thesis (PhD (Genetics))--University of Stellenbosch, 2010. / Includes bibliography. / ENGLISH ABSTRACT: The slow growth rate of Haliotis midae impedes the optimal commercial production of this most profitable South African aquaculture species. To date, no comprehensive effort has been made to identify genes associated with growth variation in farmed H. midae. The aim of this study was therefore to investigate growth variation in H. midae and to identify and quantify the expression of selected growth-related genes. Towards this aim, molecular methodologies and cell cultures were combined as a time-efficient and economical way of studying abalone transcriptomics and cell biology. Modern Illumina sequencing-by-synthesis technology and subsequent sequence annotation were used to elucidate differential gene expression between two sibling groups of abalone demonstrating significant growth variation. Following transcriptome sequencing, genes involved in growth and metabolism, previously unknown in H. midae, were identified. The expression of selected target genes involved in growth was subsequently analyzed by quantitative real-time PCR (qPCR). The feasibility of primary cell cultures for H. midae was furthermore investigated by targeting embryo, larval and haemolymph tissues for the initiation of primary cell culture. Larval cells and haemocytes could be successfully maintained in vitro for limited periods. Primary haemocyte cultures demonstrated to be a suitable in vitro system for studying gene expression and were subsequently used for RNA extraction and qPCR, to evaluate differential growth induced by bovine insulin and epidermal growth factor (EGF). Gene expression was thus quantified in fast and slow growing abalone and in in vitro primary haemocyte cultures treated with different growth stimulating factors. The results obtained from transcriptome analysis and qPCR revealed significant differences in gene expression between large and small abalone, and between treated and untreated haemocyte cell cultures. Throughout in vivo and in vitro qPCR experiments, the up-regulation of genes involved in the insulin signaling pathway provides evidence for the involvement of insulin in enhanced growth rate for various H. midae tissues. Besides the regulation of target genes, valuable knowledge was also gained in terms of reference genes, during qPCR experimentation. By quantifying the stable expression of two genes (8629, ribosomal protein S9 and 12621, ornithine decarboxylase) in various tissues and under various conditions, suitable reference genes, that can also be used in future H. midae qPCR studies, were identified. By providing evidence at the transcriptional level for the involvement of insulin, insulin-like growth factors (IGFs) and insulin-like growth factor binding proteins (IGFBPs) in improved growth rate of H. midae, the relevance of investigating ways to stimulate insulin/IGF release in aquaculture species was again emphasized. As nutritional administration remains the most probable route of introducing agents that can stimulate the release of insulin-related peptides, continuous endeavours to stimulate abalone growth through a nutritional approach is encouraged. This is the first time next generation sequencing is used towards the large scale transcriptome sequencing of any haliotid species and also the first time a comprehensive investigation is launched towards the establishment of primary cell cultures for H. midae. A considerable amount of sequence data was furthermore annotated for the first time in H. midae. The results obtained here provide a foundation for future genetic studies exploring ways to optimise the commercial production of H. midae. / AFRIKAANSE OPSOMMING: Die stadige groeitempo van Haliotis midae belemmer die optimale kommersiele produksie van hierdie mees winsgewende Suid-Afrikaanse akwakultuur spesie. Tot op hede is geen omvattende poging aangewend om gene verwant aan groeivariasie in H. midae te identifiseer nie. Die doel van hierdie studie was dus om groeivariasie in H. midae te ondersoek en om spesifieke groei-gekoppelde gene te identifiseer en hul uitdrukking te kwantifiseer. Ter bereiking van hierdie doel is molekulêre metodes en selkulture gekombineer as 'n en tydsbesparende en ekonomiese manier om perlemoen transkriptomika en selbiologie te bestudeer. Moderne Illumina volgordebepaling-deur-sintese tegnologie en daaropvolgende annotasie is gebruik om verskille in geenuitdrukking tussen naby-verwante groepe perlemoen, wat noemenswaardige groeivariasie vertoon, toe te lig. Na afloop van die transkriptoom volgordebepaling is gene betrokke by groei en metabolisme, vantevore onbekend in H. midae, geïdentifiseer. Die uitdrukking van uitgesoekte teikengene betrokke by groei is vervolgens ge-analiseer deur kwantitatiewe "real-time PCR" (qPCR). die lewensvatbaarheid van 'n primêre selkulture vir H. midae is ook ondersoek deur embrio, larwe en hemolimf weefsels te teiken vir die daarstelling van primêre selkulture. Larweselle en hemosiete kon in vitro suksesvol onderhou word vir beperkte periodes. Primêre hemosietkulture het geblyk 'n gepaste in vitro sisteem te wees om geenuitdrukking te bestudeer en dit is vervolgens gebruik vir RNS ekstraksie en qPCR, om differensiële groei, geïnduseer deur insulien en epidermale groeifaktor (EGF), te evalueer. Geenuitdrukking is dus gekwantifiseer in vinnig- en stadiggroeiende perlemoen en in in vitro primêre hemosiet selkulture wat behandel is met verskillende groei stimulante. Die resultate wat verkry is van transkriptoomanalise en qPCR het noemenswaardige verskille in geenuitdrukking tussen groot en klein perlemoen, en tussen behandelde en onbehandelde hemosiet selkulture uitgelig. Die op-regulering van gene betrokke by die insulien sein-padweg, tydens in vivo en in vitro qPCR eksperimente, bied getuienis vir die betrokkenheid van insulien in die verhoogde groeitempo van verskeie H. midae weefsels. Benewens die regulering van teikengene is waardevolle kennis ook ingewin in terme van verwysingsgene tydens qPCR eksperimentering. Deur die stabiele uitdrukking van twee gene (8629, ribosomale proteien S9 en 12621, ornitien dekarboksilase) te kwantifiseer in verskeie weefsels en onder verskeie kondisies is gepaste verwysingsgene, wat ook in toekomstige H. midae qPCR eksperimente aangewend kan word, geïdentifiseer. Deur getuienis vir die betrokkenheid van insulien, insuliensoortige groeifaktor en insuliensoortige groeifaktor-bindingsproteïene by verbeterde groei van H. midae op transkripsievlak te bied, is die toepaslikheid van bestudering van maniere om insulienvrystelling in akwakultuurspesies te stimuleer, beklemtoon. Aangesien voeding die mees waarskynlike roete is om middele wat insuliensoortige peptiedvrystelling stimuleer daar te stel, word vogehoue pogings om perlemoengroei deur die regte voeding te stimuleer, aangemoedig. Hierdie is die eerste studie wat volgende generasie volgordebepaling (“next generation sequencing”) gebruik vir die grootskaalse transkriptoom volgordebepaling van enige haliotied spesie. Dit is ook die eerste keer dat ‘n omvattende ondersoek geloods word na die daarstelling van primêre selkulture vir H.midae. ‘n Aansienlike hoeveelheid volgorde data is ook vir die eerste keer geannoteer in H. midae. Die resultate wat hier verkry is bied ‘n basis vir toekomstige genetiese studies wat maniere ondersoek om die kommersiële produksie van perlemoen te optimiseer.

Graduation date: 2003

<p>The principle aim of this study was to gain insights into the perceptions of the people living in the Cape Agulhas Area of South Africa on the issues of small-scale fishing and the historical claims to fishing rights of the communities living in the fishing villages of Struisbaai and Waenhuiskrans. A further aim was to identify the gap between knowledge and the implementation of fishing rights policies by analysing existing policies on small-scale fishing and thereby identifying possible lessons and guidelines for policy formulation. Key focus areas were the historical recollections of people, their knowledge of past, current and proposed fishing legislation and their opinions, recommendations and guidelines regarding new and proposed policies. A qualitative framework was used for this study, using key informants and the taking of life histories. The two fishing communities served as case studies and life histories were documented using semi-structured interviews. The study drew on previous research in historical practices and indigenous knowledge systems and special attention was given to scientific and archaeological research. The policy processes from 1994 to the present were described and themes were identified in the literature and the life histories. The study found that many of the methods used in earlier years is still used today, passed over from generation to generation.</p>

<p>The principle aim of this study was to gain insights into the perceptions of the people living in the Cape Agulhas Area of South Africa on the issues of small-scale fishing and the historical claims to fishing rights of the communities living in the fishing villages of Struisbaai and Waenhuiskrans. A further aim was to identify the gap between knowledge and the implementation of fishing rights policies by analysing existing policies on small-scale fishing and thereby identifying possible lessons and guidelines for policy formulation. Key focus areas were the historical recollections of people, their knowledge of past, current and proposed fishing legislation and their opinions, recommendations and guidelines regarding new and proposed policies. A qualitative framework was used for this study, using key informants and the taking of life histories. The two fishing communities served as case studies and life histories were documented using semi-structured interviews. The study drew on previous research in historical practices and indigenous knowledge systems and special attention was given to scientific and archaeological research. The policy processes from 1994 to the present were described and themes were identified in the literature and the life histories. The study found that many of the methods used in earlier years is still used today, passed over from generation to generation.</p>

The predation pressures on juvenile Haliotis kamtschatkana, northern abalone, in Barkley Sound. British Columbia, were investigated. Thirty-seven potential predators were tested in the laboratory to determine if they would consume juvenile abalone 1- 25 mm shell length (SL). Six of these potential predators consumed > 10 % of the abalone offered to them and were considered major predators. Natural mortality for juvenile H. kanntschatkana was then estimated by outplanting calcein marked and bee tagged hatchery-reared abalone at field sites. Calcein concentrations between 20 40 mg/L produced clear fluorescent marks for 3- 5 mm SL abalone when exposed to a double calcein marking procedure and abalone > 15 mm SL immersed in calcein for 72 h showed the most distinct marks. Recoveries of outplanted abalone were highest (24%) for 15.1- 20 mm juvenile abalone. I recommend outplanting juvenile abalone larger than 12 mm to increase chances of survivorship in the wild.

Thesis (MScAgric)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The abalone Haliotis midae is the most important aquaculture species in South Africa. The industry is dependent on export to Far Eastern markets in a variety of forms, including live, frozen, canned or dried. The species is considered undomesticated in the sense that the current commercial broodstock has been obtained from natural populations through a process of random collection. Global competition has necessitated the South African industry to introduce a genetic improvement program to increase biological productivity and financial profitability. The objective of this study was to assess the genetic variation and to estimate key parameters in terms of growth and yield related traits, between family groups that form part of the breeding program. The study reports on heritability estimates of growth rate (0.14 ± 0.05), canning yield (0.08 ± 0.03), and drip loss during live export (0.03 ± 0.02). The high genetic correlation (0.94 ± 0.34) between shell length and live weight enables industry to utilise either weight or shell length as a criteria during operational practices such as sorting, grading and harvesting. The correlation of 0.85 ± 0.01 between live weight and canning loss indicates that animals that weigh more have a lower dressing percentage. Based on these low heritability values obtained for yield related traits it is recommended not to include these traits in the selection program at this stage. The findings of the study were however, compromised by the availability of a limited number of family groups, the age differences between families and the effect of different locations on the variance in phenotypes. Further investigation is needed to confirm the credibility of the results. / AFRIKAANSE OPSOMMING: Die perlemoen Haliotis midae is die belangrikste akwakultuurspesie in Suid Afrika. Die industrie is afhanklik van uitvoere na markte in die Verre Ooste. ‘n Verskeidenheid van produkte word uitgevoer, insluitend lewendige, gevriesde, gedroogte en verblikte perlemoen. Die spesie word as ongedomestikeerd beskou aangesien die huidige teeldiere op ‘n lukrake wyse uit natuurlike populasies versamel is. Globale kompetisie het die Suid Afrikaanse industrie genoodsaak om ‘n genetiese verbeteringsprogram in werking te stel om sodoende die biologiese produktiwiteit en finansiële winsgewendheid te verbeter. Die studie poog om genetiese variasie in groei en opbrengsverwante kenmerke tussen familiegroepe wat deel uitmaak van die teelprogram te ondersoek. Oorerflikheid van groeitempo (0.14 ± 0.05), opbrengs na verblikking (0.08 ± 0.03), en vogverlies na lewendige uitvoer (0.03 ± 0.02) is beraam. Die hoë korrelasie (0.94 ± 0.34) tussen gewig en skulplengte stel die industrie in staat om beide massa en skulplengte as kriteria te geruik tydens operasionele praktyke van sortering, groepering en oes. Die korrelasie van 0.85 ± 0.01 tussen gewig en verlies na verblikking dui aan dat swaarder diere ‘n laer uitslagpersentasie het. As gevolg van die lae oorerflikheidswaardes vir opbrengsverwante kenmerke word daar aanbeveel dat hierdie kenmerke nie op hierdie stadium ingesluit word in die seleksieprogram nie. Resultate is egter beïnvloed deur ‘n beperkte aantal familie groepe, ouderdomsverskille tussen families en die effek van verskillende lokaliteite op die variansie in die fenotipes. Verdere ondersoeke is nodig om die geloofwaardigheid van die bevindinge te bevestig.

Thesis (MSc)--University of Stellenbosch, 2008. / ENGLISH ABSTRACT: The five leading abalone producers in South Africa have initiated a genetic enhancement program for Haliotis midae in a collaborative effort to improve economically valuable traits. Several independent objective-specific studies were initiated, including the establishment of a Performance Recording Scheme (PRS), utilised in this study, and necessary to monitor the ongoing performance of individuals as the move from mass-selection to marker assisted selection (MAS) is implemented. The primary objective of this study was parentage assignment of F1 offspring mass-selected for size at approximately one year and allocated to either a “faster” or a “slower” growth group. Nine microsatellite markers were used to genotype juveniles and potential parents, with assignment completed using CERVUS 2.0. Average growth results for Abagold and HIK were comparable for both growth groups. Slight environmental effects, although not statistically significant, were evident as growth advantages for juveniles within the faster growth group at two of the five locations and for juveniles within the slower growth group at one of the five rearing locations. Despite measures to standardise environmental influences, variables are difficult to control within the reality of a production environment; and potential genotype x environment interactions may require further investigation and factoring into future breeding programs. The additional costs associated with MAS often make the technology prohibitive to most aquaculture operations, despite the significant genetic gains to be realised from its implementation. Cost-optimising routine processes such as DNA extractions may be one approach to reduce these additional costs. Chelex®100 appears to be a suitable alternative to the CTAB method – being quick and cost-effective to perform. Applying this method in combination with the high throughput of a robotic platform warrants further evaluation. For the microsatellite development, 50% of positive recombinant clones contained inserts. Sequencing of these clones produced 16% perfect repeats and 47% imperfect repeats for which 52 primer sets were designed and tested. In total, 31 polymorphic microsatellite loci of different motifs and composition were developed. Sixty-one percent of sequenced clones were deemed redundant and pre-screening for both uniqueness and the presence of microsatellites would reduce unnecessary sequencing thus improving the efficiency of the FIASCO method and reducing costs. Nine loci were selected for parentage assignments. Null alleles were present for all the selected markers; however, frequencies were below the critical level of 5%. Parentage yielded 91% and 90% successful assignment for Abagold and HIK respectively; however, observations indicate that a measure of relatedness may exist between breeders. Recommendations with regards to future family breeding include, for both Abagold and HIK, retaining selected breeders based on their respective contributions to the F1 progeny while reassessing the potential of remaining breeding stock under more controlled breeding conditions. No obvious trends were observed for growth with most individuals producing both faster and slower growing offspring. Juveniles will be reassessed at two years to determine whether the size advantage or disadvantages were maintained and to ascertain whether growth advantages/disadvantages may be gender specific. / AFRIKAANSE OPSOMMING: Die vyf mees toonaangewende perlemoen produseerders in Suid Afrika het „n genetiese verbeteringsprogram vir Haliotis midae geinisieer in „n gesamentlike poging om ekonomiese belangrike eienskappe te verbeter. Verskeie onafhanklike fokus-spesifieke studies is geinisieer, insluitend die totstandkoming van „n groeiprestasie aantekenstelsel, soos gebruik in hierdie studie, en wat noodsaaklik is om die aaneenlopende prestasie van individue te moniteer soos daar beweeg word van massa seleksie tot merker bemiddelde seleksie. Die primêre fokus van hierdie studie was die ouerskapsbepaling van F1 nageslag wat massa geselekteer is op ouderdom 1 jaar vir grootte en as of “vinniger” of “stadiger” groeiers geklassifiseer is. Nege mikrosatelliet merkers is gebruik om jong perlemoen individue en moontlike ouers te genotipeer, met die ouerskapstoekenning bereken deur CERVUS 2.0. Groei resultate vir Abagold en HIK was vergelykbaar vir beide groei groepe op drie van die lokaliteite. Geringe omgewingseffekte, alhoewel nie statisties betekenisvol nie, was sigbaar as „n groei voordeel vir jong individue op twee van die vyf lokaliteite. Ongeag maatstawe om omgewingsinvloede te standardiseer, is varieerbares moeilik om te beheer in die produksie omgewing en genotipe x omgewings interaksies mag verdere navorsing vereis en behoort in ag geneem te word in toekomstige telingsprogramme. Die onkoste wat met merker bemiddelde seleksie geassosieer word, maak die tegniek soms onaantreklik vir die meeste akwakultuur operasies; nie teen staande die genetiese voordele wat die gebruik daarvan veroorsaak. Die koste-optimiseering van roetine prosesse, soos byvoorbeeld, DNA ekstraksies, is dalk een aanslag om die addisionele koste te verminder. Chelex®100 blyk „n geskikte alternatief tot die CTAB metode te wees – die tegniek is vinnig en koste-effektief om uit te voer. Die gebruik van hierdie metode in kombinasie met die hoë deurvloei van ‟n robotiese sisteem behoort verder ondersoek te word. Vir die mikrosatelliet ontwikkeling het slegs 50% van die positiewe rekombinante klone invoegings bevat. Nukleotiedvolgorde bepaling van hierdie klone het 16% perfekte herhalings en 47% onderbroke herhalings bevat waaruit 52 inleierstelle ontwikkel en getoets is. In totaal is 31 polimorfiese mikrosatelliet loki van verskillende motiewe en samestelling ontwikkel. Een-en-sestig persent van die volgorde bepaalde klone is oortollig geag en vooraf sifting vir beide uniekheid en die teenwoordigheid van mikrosatelliete sal onnodige volgorde bepaling verhoed, die effektiwiteit van die FIASCO tegniek verhoog sowel as addisionele koste verminder. Nege loki is geselekteer vir ouerskapsbepaling. Nul allele was teenwoordig vir al die geselekteerde merkers, maar die frekwensies was egter laer as die 5% kritieke waarde. Ouerskap is 91% en 90% suksesvol bepaal vir Abagold en HIK onderskeidelik. Waarnemings dui egter daarop dat daar verwantskappe mag wees tussen van die broeidiere. Voorstelle in terme van toekomstige familie teling sluit is, vir beide Abagold en HIK, om geselekteerde broei diere te behou gebaseer op hulle onderskeie bydraes tot die F1 nageslag asook die herevaluaring van die potensiaal van die oorblywende broei diere onder meer beheerde teling toestande. Geen voor-die-handliggende tendense is waargeneem vir groei nie met die meeste individue wat beide vinniger en stadiger groeiende nageslag geproduseer het. Jong individue moet geherevalueer word op tweejarige ouderdom om te bepaal of die groei voordeel of nadele behou is en om te bepaal om groei voordele/nadele geslagspesifiek is.