No description available.

The Roe’s abalone (Haliotis roei) fishery near Perth, Western Australia, is uniquely accessible, and highly vulnerable to overexploitation. The sustainability of this intensively utilized fishery requires robust assessment. To facilitate an assessment, this research aimed to provide rigorous and detailed biological information with appropriate interpretation. Four critical aspects of the species’ biology and population dynamics were investigated: (1) the stock structure; (2) the recreational catch; (3) an appropriate growth curve and description of size at age; and (4) abundance measures against which to assess the impact of fishing mortality. Allozyme electrophoresis was used to investigate stock structure across the species’ distribution. Standardized variance in allelic frequencies between 10 sites in south-western Australia indicated high levels of gene flow across the 3000 km sampled (mean FST = 0.009). An isolation-by-distance was evident when pairwise measures of GST were related to geographic distance (r=0.45, P<0.001). The area of complete genetic mixing was estimated from samples within the Perth fishery to be less than the distance between the two nearest sites, or 13 km. Consequently, the Perth fishery comprises numerous discrete stocks, each requiring independent assessment. A possible mechanism for this population structure is the retention of larvae in the wind driven currents oscillating in the near-shore lagoons, with rare pulses of long distance dispersal via the southerly Leeuwin current, running further offshore. The presumed impact of intensive recreational fishing, combined with substantial commercial quotas for the Perth fishery, had led to tight restrictions on fishing effort, without any quantitative measure of the recreational catch. A stratified creel survey was adapted to estimate the effort, catch rate and mean weight of abalone harvested by the recreational sector. Catches were estimated for reef complexes, or stocks, of less than 10 nautical miles (18.5 km) of coast. Between 1997 and 2000 the recreational catch varied from 30 to 45 tonnes whole weight, approximately equivalent to the commercial quota of 36 tonnes. On average 88% of the recreational catch came from two stocks, while 98% of the commercial catch came from these two, and one additional, stocks. The incidental mortality from recreational fishing, measured as the number of abalone left dead on the reef as a proportion of the estimated catch, was approximately 7% and 20% at two sites surveyed. Spatial and temporal patterns of growth were examined on the west coast of Western Australia. Growth increments were measured for abalone larger than about 30 mm from tagging studies at five sites in the Perth fishery, a site at the northern extent of the species’ distribution and a site in the southwest. Mean annual growth increments of the 0+ year class were obtained by fitting components to length frequencies from five sites in the Perth fishery, and combined with growth increments from each Perth tag site for model fitting. A von Bertalanffy growth curve provided a slightly better fit to the tag data, but a Gompertz growth curve was a much better fit when the mean increment from the 0+ to 1+ cohort was included, with the inflection occurring at about 40 mm, the size at sexual maturity. There was no difference in annual growth between the two years studied. There was significant variation in growth between the reef platform and adjacent sub-tidal reef, but this variation was site specific and faster growth rates were not consistently associated with either habitat. There was no latitudinal trend in growth rate. Growth at the Perth sites was the fastest and similar at all five sites with growth increments greater in summer than in winter. Size and abundance of abalone were measured using fixed transects and quadrats. Abalone densities were highest on the outer edge of the platform, intermediate in the middle of the reef platform, and lowest on both the inner platform and the sub-tidal reef. The pattern of mean lengths of abalone was the inverse of the density. Mean length and abundance were driven by the presence of post-settlement juveniles on the outer and middle reef habitats. There was a high spatial variation in abundance, with densities varying between transects at the same site, but the trend between years for each transect at a site was not significantly different. Abalone abundances, by size class, were examined from sites sampled between 1996 and 2002. A low density of post-settlement juveniles at all sites in 1997 was reflected in low densities of the 1+ and 2+ year classes in subsequent years. Abalone abundances at an unfished site were steady over the seven years. Two sites were located within each of the main stocks utilised by the recreational fishery. Abundance was stable or increasing in one stock, corresponding to a stable total catch. In the second stock the total catch increased over time and abundances declined. Perth is the focus of the Roe’s abalone fishery, with recreational and commercial fishers take about equal shares of the annual catch. Stocks are highly subdivided, with most of this catch coming from only 3 stocks occupying about 20 nautical miles of coast. Growth rates were found to be lower than previous estimates, and more similar to other commercial species of abalone. All life history stages are highly habitat specific, particularly the recruits, and the distribution and abundance through time indicate that the main stocks are near, or slightly over, the limit of sustainable fishing.

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.

Thesis (MPhil (Animal Sciences. Aquaculture))--University of Stellenbosch, 2006. / T. heterouncinata is a sabellid polychaete endemic to South Africa and found primarily in the shells of the abalone Haliotis midae. With the intensification of abalone aquaculture around the world, T. heterouncinata has become a problematic pest by causing shell deformities, reducing abalone growth rates and, in some instances, high abalone mortalities. The problem of this sabellid was first noticed in Californian in the early 1980’s in Red abalone (Haliotis rufescens) production facilities. Many mitigation methods have been tested over the years and this paper investigates another two methods; a reduction in particulate load in the tank to reduce the food source of the sabellid which perhaps will reduce fecundity, and to use ultrasound as a possible mitigation method. This study found that filtration and reduction in suspended particles did not have a significant effect, but that ultrasound did have a significant effect in reducing T. heterouncinata populations.

Thesis (MBA (Business Management))--Stellenbosch University, 2008. / ENGLISH ABSTRACT: This report begins with a look at the ever increasing world population and the effect this is having on the world's food production. While the demand is increasing with the rise in population, the supply side is finding it difficult to produce enough food due to a number of pressures. The report then goes further by suggesting a source of food that holds great potential for the future which, if it reaches its full potential, could go a long way in providing a sustainable source of food for the next generation. This source is Aquaculture, which is discussed through a look at both the advantages it provides and the challenges involved within this industry. Furthermore, the report takes an in depth look at a sub-section of the aquaculture industry, namely the farming of abalone, firstly in general, but then also more specifically the farming of abalone in South Africa. Abalone are mostly sold in Asia as a high priced delicacy and occurs naturally off the coast of South Africa, however, due to over fishing and poaching over the past three decades, the South African government has now introduced a total ban on the diving and selling of wild abalone, or as it is commonly known in South Africa, Perlemoen. It is therefore now up to the small number of abalone farms on South Africa's coast to fill the void left in the international abalone market for Haliotis midae. The second half of this report looks at one company in particular, Aquamart, which was a company established in 2003 by 5 MBA students with an ambitious plan of setting up an abalone farming facility. All of Aquamart's aspects are discussed, including its business plan, financials, senior management and its strategy. These areas are then critically reviewed in order to try and establish what Aquamart succeeded in, but also what went wrong, and why the company ultimately had to be closed down in 2005. This report aims to identify some of the barriers within this industry and also for Small and Medium Enterprises (SMEs) in general, which can hopefully be used by future entrepreneurs in order not to repeat the mistakes made by Aquamart. / AFRIKAANSE OPSOMMING: Die verslag begin deur te kyk na die al groeiende wereldbevolking en die druk wat dit plaas op die wereld se voedselvervaardiging. Saam met die druk van die groeiende vraag, is daar ook verskeie eksterne vorme van druk op die aanbod van voedsel. Die verslag gaan verder deur een moontlike bron van voedsel voor te stel wat sal kan help om aan die vraag te voldoen, maar slegs indien dit korrek aangewend word. Die bron is akwakultuur, en die verslag kyk na die industrie se voordele asook na van die uitdagings wat die sukses van die industrie kan beinvloed. Verder ondersoek die verslag oak een van akwakultuur se sub-industriee, naamlik die boer met perlemoen, eers op 'n globale skaal, en dan spesifiek in Suid-Afrika. Die perlemoen wat grotendeels as 'n luukse voedsel op die Asiatiese mark verkoop word kom natuurlik op die kus van Suid-Afrika voor, maar as gevolg van die swak bestuur van die natuurlike hulpbron, gepaard met die onwettige smokkeling van perlemoen, is die natuurlike perlemoen nou 'n bedreigde spesie in Suid-Afrika, en het die land se regering 'n verbod geplaas op die uithaal en verkoop van wilde perlemoen. Dit is dus in die hande van die Suid Afrikaanse perlemoenplase om in die wereld se vraag na H. midae te voorsien. Die tweede helfte van die verslag doen 'n gedetailleerde ondersoek op die maatskappy Aquamart, wat in 2003 gestig was deur 5 MBA studente met die oog om 'n perlemoenplaas in Suid-Afrika op te rig. Die vernaamste aktiwiteite van Aquamart word in die gedeelte bespreek, insluitende, onder andere, die besigheidsplan, finansies, algemene bestuur en Aquamart se besigheidstrategie. Die verslag doen dan 'n kritiese ondersoek op Aquamart om te probeer vasstel hoekom die bestuur in 2005 geforseer was om Aquamart se deure te sluit. Die hoop is om lesse te leer uit Aquamart se mislukking wat kan dien as 'n riglyn vir toekomstige perlemoenboere, asook klein en medium-besighede in die algemeen.

L’aquaculture des ormeaux (Haliotis spp.) fournit un bon cas étude des défis techniques, sociaux et environnementaux concernant l'introduction d’organismes marins nouvellement domestiqués sur le marché. En effet, l'élevage de l'ormeau a débuté au Japon au cours des années 1960 et, d'après la FAO (2012), est aujourd'hui l'une des industries aquacoles les plus dynamiques dans le monde. Pourtant, toutes les tentatives n'ont pas connues le même succès. Cette dissertation vise à comprendre les facteurs qui ont permis ou entravé le succès environnemental, social et technique de l’halioticulture, en mettant l'accent sur la France. Plus précisément, nous examinons trois grandes catégories de facteurs qui peuvent expliquer son évolution: - L'importance des facteurs socio-écologiques dans la gestion de la ressource en ormeaux - Les facteurs socioculturels qui étayent le statut de l'ormeau en tant que ressource éligible pour l'aquaculture. - Le rôle de la science dans l'industrialisation de l'élevage d'ormeaux. / Abalone aquaculture (Haliotis spp.) or halioticulture provides a good case study of the technical, social and environmental challenges of introducing newly domesticated marine organisms into the market. Abalone farming began in Japan in the 1960s and, according to FAO (2012), is now one of the most dynamic aquaculture industries in the world. Yet all attempts have not met with the same success. This essay aims to understand the factors that have allowed or hindered the environmental, social and technical success of halioticulture, with an emphasis on France.More specifically, we examine three main categories of factors that may explain its evolution:- The importance of socio-ecological factors in the management of abalone resource.- Socio-cultural factors that support the status of the abalone as an eligible resource for aquaculture.- The role of science in the industrialization of abalone farming.

This thesis focussed on the effects of a range of trace metals on various stages of Haliotis rubra development. The trace metals assessed in this thesis were the essential metals Cu, Zn and Fe; and, the non-essential metals Hg, Cd and Pb. Copper and Hg proved to be the two most toxic metals to the life stages of H. rubra studied. The concentrations affecting normal development of the fertilised egg exposed for 48h showed a decreasing order of toxicity with 48hEC50 recorded at 7µg Cu/L, 20µg Hg/L, 42µg Zn/L, 4,102µg Fe/L, 4,515µg Cd/L, and 5,111µg Pb/L. Settlement and metamorphosis occur in normal larvae when aged 5 days, and exposure of the 5 day old larvae to the metals for 48h resulted in impaired crawling success at 128µg/L Cu and Hg, and 1250µg Cd/L. Settlement was inhibited after exposure to 128µg Cu/L, 32µg Hg/L, and 1250 Cd/L. Metamorphosis of larvae 96h after exposure was inhibited by 32µg Cu/L, 512µg Zn/L, 32µg Hg/L and 625µg Cd/L. The rate of meta morphosis was enhanced after exposure to Cu and Hg at 0.5µg/L and 64 - 256µg Zn/L. Exposure to Zn at concentrations 64, 128 and 256 µg Zn/L caused an increased rate of settlement and metamorphosis. Juvenile H. rubra exposed to the six metals for 96h were most sensitive to Cu, which produced a 96hLC50 of 87µg Cu/L compared to Hg with a 96hLC50 of 173µg Hg/L. Juvenile H. rubra were relatively insensitive to Zn and Cd with the 96h LC50 of 1730µg Zn/L and 3700µg Cd/L, respectively. Exposure to individual solutions of Cu, Zn, and Cd for 28 days resulted in juvenile H. rubra bioaccumulating significant concentrations of metals in the visceramantleedible foot muscle. Accumulation of Hg was greater in the mantle-viscera-edible foot muscle. Following exposure, depuration in clean seawater for 28 days produced varying decreases in metal concentrations for each tissue compartment. Sodium-potassium activated ATPase (Na+,K+-ATPase) activity in the gills of juvenile H. rubra was significantly affected following expos ure to the trace metals for 28 days, with a decreasing order of effect on enzyme activity of Hg-Cu-Cd-Zn. Depuration of H. rubra in clean seawater for 28 days resulted in the recovery of Na+,K+-ATPase activity to varying degrees. The recovery of ATPase activity was more efficient following exposure to Cd-Zn-Cu-Hg. The overall results of this thesis provide initial baseline information to evaluate the sensitivity of H. rubra to trace metal toxicants, and these results may be utilised by regulators for establishing marine water quality guidelines to protect H. rubra and other abalone species in their natural habitats.

Regulation of transcription is an important molecular mechanism through which organisms can respond to environmental change. Environmentally-related transcriptional variation can play a significant role in evolution, potentially acting as a mechanism for the formation of new adaptive phenotypes. Organisms are most sensitive to the influence of external environmental variation during development, yet very few studies have explored environmentally-related transcriptional variation in early life history stages. Marine invertebrate metamorphosis, where intimate larval-environment interactions trigger settlement onto the benthos and a drastic morphological shift from larval to adult form, exemplifies the influence of environment on development. Variation in both the timing of metamorphosis and the form of specific metamorphic inductive cues, even at an intraspecific level, suggests that larvae have molecular mechanisms for surviving settlement and metamorphosis in a range of environmental conditions. The extent of transcriptional variation at metamorphosis remains largely unknown due to limited information on both the natural inductive cues and the molecular mechanisms directing metamorphosis in marine invertebrates. Contributing to current understanding of the interplay between genes, environment and phenotype during development, I explored molecular and ecological aspects of metamorphosis in a marine invertebrate, the tropical abalone Haliotis asinina. First, I employed cDNA microarray methods to identify candidate genes and document widespread transcriptional changes occurring in Haliotis asinina larvae during larval development and metamorphosis. Microarray results reveal that as the abalone veliger larva matures, it requires coordinated regulation of temporally different gene batteries involved in a wide range of physiological and developmental processes associated with the transition to a new, benthic habitat. All candidate genes showed changes in expression following exposure of larvae to coralline algae, an external inductive cue, demonstrating the remarkable effect of environment on transcription during marine invertebrate metamorphosis. 144 genes, ~40% of which are novel, were identified as candidates for a role in H. asinina metamorphosis. This high proportion of novel genes indicates that the conserved signaling pathways operating in marine invertebrate metamorphosis likely regulate the expression of taxon-specific genes. The relationship between abalone larvae and their natural inductive cue, coralline algae, is species-specific. To characterize the metamorphic cue preferences of Haliotis asinina larvae from Heron Island Reef, Australia, I documented larval induction response to a number of different coralline algae species commonly found in adult H. asinina habitat. H. asinina larvae exhibit highly specific responses to induction of metamorphosis by different coralline algae species, with 0 – 100% metamorphosis by 48 hours post induction depending on algae species. Unlike any other abalone species studied, the most effective inducers of Heron Island Reef H. asinina are articulated corallines of the genus Amphiroa. Comparing the response of different larval families to select species of coralline algae indicated that coralline algae community composition is likely to significantly impact H. asinina population structure. Additionally, I compared larval response to dead and live coralline algae to show that induction specificity is driven by chemical, not physical, properties. Characterization of the surface cell biomarkers of three different coralline algae species indicates that algal biomolecular composition relates to variations in H. asinina induction response. To explore the influence of variation in larval induction environment, I compared transcription patterns of 17 metamorphosis-related genes in Haliotis asinina larvae induced by three different species of coralline algae. H. asinina post-induction gene expression profiles vary according to the species of coralline algae inducer. This transcriptional variation occurs in genes with diverse functions and spatial expression patterns, highlighting the global nature of the impact of benthic microhabitat on gene expression. The environment-specific modulation of gene expression in H. asinina post-induction may be a means for marine invertebrates to cope with changes in their settlement environment at metamorphosis. Genes expressed in the larval sensory structures acting to detect external metamorphic cues may be particularly good candidates for studying environmentally-related transcriptional variation. I identified three novel genes expressed in putative sensory structures of Haliotis asinina larvae just prior to metamorphosis. The spatial and temporal expression patterns of these genes correlate with changes in larval ciliation patterns throughout metamorphosis, strongly suggestive of a role in metamorphic initiation. The three genes exhibit significant overlap in spatial expression profiles, indicative of genetic crosstalk between different sensory systems at metamorphosis. Transcriptional variation in gastropod sensory system genes may have assisted the evolution of different metamorphic inductive cues for different species. The results presented here establish an important role for transcriptional variation during marine invertebrate metamorphosis. Transcriptional variation underlies the morphological change from larval to adult body plan and also appears to assist larval recruitment in variable benthic habitats. Modulation of gene expression at metamorphosis in response to the environment may ultimately influence marine invertebrate species biogeography and evolution.

Thesis (Ph. D.)--University of California, Riverside, 1995. / Includes bibliographical references (leaves 342-367).

Thesis (MSc)--University of Stellenbosch, 2004. / ENGLISH ABSTRACT: The indigenous abalone, Haliotis midae has been a successfully cultured aquaculture species in South Africa since 1990. It has a slow growth rate and takes from two to five years to reach market size. Like for most other commercially important abalone species, the slow growth rate of H. midae is a cause of concern with regard to the profitability of farming and global competitiveness of the species. Ploidy manipulation of the maternal genome, a universally growing practice in shellfish culture, is considered a promising method to improve the growth rate of abalone - a desirable trait in aquaculture organisms from a commercial perspective. This manipulation technique is employed to achieve sterility, which results in limited gonad development. The consequent re-allocation of resources to somatic growth results in improved growth. The purpose of this study was to establish a viable method for the induction and validation of triploidy, on a commercial scale, in the South African abalone, H. midae. The focus was on hydrostatic pressure as a method of induction and flow cytometry as the method of validation. The results obtained confirm hydrostatic pressure as an effective method for the induction of triploidy in H. midae, delivering high percentages of triploidy (>80%) over a wide range of pressures and times, in 48 hour-old larvae. Hydrostatic pressure had a negative effect on survival in 20 hour-old larvae. Flow cytometry was validated as a reliable, fast and accurate, though expensive, method for identification of triploidy in H. midae. As an outcome of this study a manual of “Procedures for the Induction and Validation of Triploidy in the abalone” is presented (Appendix 1) together with recommendations for further studies on triploidy in the South African abalone, H. midae. / AFRIKAANSE OPSOMMING: Die inheemse perlemoen, Haliotis midae, is sedert 1990 ‘n suksesvol gekweekte akwakultuur spesie in Suid-Afrika. ‘n Kenmerk van die spesie is die stadige groeitempo van tussen twee en vyf jaar ten einde bemarkbare grootte te bereik. Soos vir die meerderheid perlemoen van kommersiële belang, is hierdie stadige groeitempo rede tot kommer met betrekking tot die winsgewende kweek en wêreldwye mededingendheid van die spesie. Die manipulasie van ploïdie van die moederlike genoom is ‘n toenemende praktyk in skulpvisboerdery en word gereken as ‘n belowende metode om die groeitempo van perlemoen te verbeter. Hierdie manipulasietegniek word gebruik om steriliteit te verkry wat manifesteer as onderdrukte ontwikkeling van die geslagsklier. Die gevolg is die herkanalisering van bronne na somatiese groei. Die doel van hierdie studie was om ‘n lewensvatbare metode vir die induksie van triploïdie op ‘n kommersiële skaal in die Suid-Afrikaanse perlemoen, H. midae, te vestig. Daar is op hidrostatiese druk as metode vir die induksie en vloei-sitometrie as metode vir die geldigverklaring van triploïdie gefokus. Die resultate van hierdie studie bevestig dat hidrostatiese druk ‘n effektiewe metode vir die induksie van triploïdie in H. midae is. Hoë persentasies van triploïdie (>80%) is oor ‘n wye reeks van drukke en tye in 48 uur oue larwes verkry. Daar is gevind dat hidrostatiese drukbehandeling ‘n negatiewe effek op die oorlewing van 20 uur oue larwes het. Vloei-sitometrie is bevestig as ‘n betroubare, vinnig en akkurate, maar duur metode vir die identifikasie van triploïdie in H. midae. As ‘n uitvloeisel van die studie word ‘n handleiding “Procedures for the Induction and Validation of Triploidy in the abalone” (Appendix 1) aangebied tesame met aanbevelings vir verdere studies rakende triploïdie in die Suid-Afrikaanse perlemoen, H. midae.