Dissertations / Theses: 'Aquaculture'

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Erzini, Gabriel de Castro. "Automatic control of an aquaculture system." Master's thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/16545.

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Mestrado em Engenharia Mecânica
This thesis covers the automated aquaculture scenario around the world and speci cally Portugal. With research done, a case study and laboratory work, the goal is to create a reliable remote control system capable of not only controlling the physical variables within an aquaculture system but monitor and rectify unwanted situations.
Esta tese trata-se de aquacultura pelo mundo e Portugal especi camente. Com uma pesquisa feita, um "case study" e trabalho laboratorial, o objetivo é criar um sistema de controlo remoto capaz de controlar as variáveis físicas dentro de um sistema de aquacultura e monitorizar e reti car situações indesejadas.

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Switz, Theodore R. "Sustainability of applied aquaculture in the US." Online pdf file accessible through the World Wide Web, 2007. http://archives.evergreen.edu/masterstheses/Accession86-10MES/Switz_T%20MESThesis%202007.pdf.

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Stewart, J. Alan. "Assessing sustainability of aquaculture development." Thesis, University of Stirling, 1995. http://hdl.handle.net/1893/2164.

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Aquaculture, as an aquatic based economic activity, has risen from relative obscurity to a position of global recognition in just over two decades, and is forecast to become increasingly important in the next century. This growth, however, has been accompanied by increasing concerns over the environmental and social costs associated with the exploitation of the natural resource base on which it depends. This occurs in the broader context of increasing awareness of the finite capacity of the global system, and the need for development of more sustainable resource management regimes. The objective of the study is to examine if and how 'sustainability' can be brought into assessment for aquaculture development. The main concepts of sustainability are discussed, and key issues for assessment identified. The range of impacts associated with aquaculture development is reviewed, and broad categories of sectoral sustainability indicators proposed. Specific issues and assessment approaches are examined in three case studies, focusing on environment interactions, resource use assessment, and the rural development context, respectively. There follows a structured analysis of applicability of selected generic appraisal methods, concluding that while all may contribute, none is sufficiently broad to account for all sustainability perspectives. A more comprehensive framework for the assessment is therefore proposed, by which sustainability features of any system can be described, potential indicators and methods of assessment identified, and results communicated to the decision making process. This does not offer a definitive judgement on sustainability, but presents an holistic view, allowing explicit recognition of trade-offs involved between conflicting sustainability objectives. It is concluded that sufficient information is available for this approach to be developed and applied on a wider basis. Constraints to more sustainable development relate more to the social, political and economic environment than to problems of uncertainty in forecasting biological and physical systems.

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Dieta, Romeo Esquivel. "Aquaculture development in the Philippines." Thesis, University of Hull, 1997. http://hydra.hull.ac.uk/resources/hull:4708.

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Philippine aquaculture is a dynamic industry and a fast growing sector of the economy. Tremendous progress in production and technology has been achieved during the past decade. However, the country is experiencing a fish production shortfall which the aquaculture sector is expected to address. Given the proper support and direction, the aquaculture industry in the Philippines has great potential for growth and development. The Philippines has the principal attributes necessary for expansion of aquaculture production (e. g. important aquaculture species, ideal climatic conditions, existing fish farms and large water resources, expertise and manpower, markets, technologies). As part of the present research, several production-oriented studies were conducted for the development of the brackishwater aquaculture sector. The studies have shown that aquaculture technologies are available (e. g. milkfish - semi-intensive culture in ponds and marine cage culture, salt-tolerant tilapia hybrid - pond-based and marine-based cage culture, grouper - pond culture, shrimp - semiintensive culture) which are technically feasible and financially viable under present economic and environmental conditions. However, there are several important aquaculture constraints (e. g. seed supply and quality, feed supply and quality, government policies, marketing and post-harvest, environmental degradation and diseases, aquaculture credits) that must be overcome in order for the country to attain the maximum benefit from the potential of aquaculture. The study also identifies the important socio-economic benefits that can be derived (e. g. contribution to Gross Domestic Product, fish food supply, foreign exchange earnings, employment opportunities, tax revenues) from the development of the aquaculture sector. Finally, the study provides some strategies for the development of the brackishwater aquaculture sector with emphasis on the culture of milkfish, salt-tolerant tilapia hybrid, grouper and shrimp.

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Gyllander, David. "Ethical Aspects of Norwegian Aquaculture." Thesis, Linköpings universitet, Institutionen för kultur och kommunikation, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-124237.

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The Norwegian government has submitted a report to the Norwegian parliament, concluding that raw oil export can no longer sustain economic growth. Norway is therefore seeking other industries to minimize the economic loss this is causing. Norway is already the largest exporter of salmon and trout in the world. The report states that the government's goal is to increase production to five times today's production by 2050. The ability and desire to grow has its backing from a handful of large companies dominating the aquaculture business and a newly recognized right-wing government eager to make the playroom larger for the aquaculture industry. This paper analyzes the report, using an ethical matrix, looking for ethical arguments from the government as well as defining the stakeholders affected by the government's goal. This thesis' aim is to analyze and discuss the broad range of ethical concerns, based on an ethical matrix, so that a variety of ethical perspectives can be included in an evaluative discussion.

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Yoshida, Grazyella Massako. "Mate selection in aquaculture species." Universidade Estadual Paulista (UNESP), 2018. http://hdl.handle.net/11449/153170.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
Os objetivos deste trabalho foram: (i) testar a eficiência do algoritmo de seleção de acasalamento (MS) em controlar o nível de endogamia e coascendência, além de aumentar os ganhos genéticos; (ii) incluir a variabilidade genética da futura progênie como componente de otimização na função objetiva de seleção de acasalamento usando dados de dois programas de melhoramento aquícolas; e (iii) comparar a MS com a seleção truncada (TS) e contribuição genética ótima (OCS), combinados com diferentes estratégias de acasalamentos para controlar a endogamia e manter os mesmo níveis de ganhos genéticos. Para os objetivos (i) e (ii), o total de 8.782 tilápias do Nilo (NT) de cinco gerações e 79.144 salmões coho (CS) de oito gerações foram utilizados para otimizar as funções objetivos e vinte gerações discretas foram simuladas para o objetivo (iii), considerando 50 famílias e 2.000 filhos por geração, e uma característica com herdabilidade igual a 0.30. As OFs foram otimizadas considerando a coascendência média dos pais, o mérito genético esperado, a endogamia da futura progênie para os objetivos (i) e (iii) e a variabilidade genética da futura progênie foi adicionada na OF para o objetivo (ii). Para o objetivo (i), a MS permitiu reduzir a endogamia em até 73% para tilápia do Nilo, em comparação com a seleção truncada e até 20% para o salmão coho, em comparação com o cenário real de acasalamento. No objetivo dois, a MS permitiu produzir progênie com maior (DP = 0.77 e 0.30 para NT e CS, respectivamente) ou menor (DP = 0.25 e 0.14 para NT e CS, respectivamente) dispersão dos valores genéticos, dependendo da função objetivo otimizada. A seleção de acasalamentos superou a seleção truncada e o cenário real de acasalamento e também foi possível alterar a variabilidade genética da futura progênie, quando esse componente foi considerado na OF utilizado os dados reais. Para os dados simulados, a MS teve melhor performance comparada com a TS e a OCS combinada com acasalamentos aleatórios. A curto-prazo, a MS foi mais eficiente do que a OCS combinada com os acasalamentos que minimizam a endogamia em controlar a endogamia sob o mesmo nível de ganho genético. Porém, a longo prazo os resultados entre as duas estratégias foram muito semelhantes. De forma geral, o algoritmo de seleção de acasalamentos foi eficiente e flexível em otimizar a função objetiva usando diferentes componentes, em diferentes aplicações práticas na aquicultura.
The aims of this work were: (i) test the efficiency of mate selection (MS) algorithm in controlling the inbreeding and coancestry level, as well, increase the genetic gain; (ii) include the genetic variability of the future progeny as component for the optimization of the MS objective function in two aquaculture real dataset; and (iii) compare MS among truncation selection (TS) and optimum contribution selection (OCS) scenarios combined to different mating strategies to assess the best method in controlling inbreeding and maintain the genetic gain, for aquaculture breeding using simulated dataset. For objective (i) and (ii), a total of 8,782 Nile tilapias (NT) from five generations and 79,144 coho salmon (CS) from eight generations were used to optimize the objective functions (OF) and twenty discrete generations were simulated for the objective (iii), considering 50 families and 2,000 offspring per generation, and a trait with heritability of 0.30. The OFs were optimized accounting to coancestry of parents, expected genetic merit and inbreeding of the future progeny for the objective (i) and (iii) and in addition the genetic variability of the future progeny was considered for the objective (ii). For the objective (i), the mate selection allowed reducing inbreeding up to 73% for NT, compared with truncation selection, and up to 20% for CS, compared with realized scenario. In the objective (ii), MS allowed producing animals with higher (SD = 0.77 and 0.30 for NT and CS, respectively) or lower (SD = 0.25 and 0.14 for NT and CS, respectively) dispersion of estimated breeding value, depending on the objective function optimized. For real data set the MS outperformed the real mates and truncation selection and in addition the genetic variability of the future progeny could be changed when this component was considered in the OF. For the simulated dataset, the MS outperformed the TS and OCS followed by random mating. In the short-term, MS was more efficient than OCS + inbreeding minimizing in controlling inbreeding under the same genetic gain. However, in the long-term, OCS and MS resulted in similar genetic progress and average inbreeding, under the same weight on coancestry. In general, the mate selection algorithm was efficient and flexible to optimize objective functions accounting for different components, under practical applications in aquaculture breeding.
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Huang, Ying. "Antibiotic Resistance in Aquaculture Production." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1417709599.

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CHEMELLO, GIULIA. "Application of nanotechnologies in aquaculture." Doctoral thesis, Università Politecnica delle Marche, 2018. http://hdl.handle.net/11566/252915.

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Le nanotecnologie possiedono un vasto potenziale nella produzione di materiali con nuove ed uniche proprietà attraverso il controllo e la manipolazione della materia su scala atomica e molecolare. Le nanoparticelle giocano un ruolo importante nello sviluppo della nanotecnologia, grazie alle loro caratteristiche uniche hanno favorito la crescita nella produzione di materiali su nanoscala e il loro impiego in molteplici settori. I principali vantaggi derivanti dall’uso delle nanoparticelle sono rappresentati dalle loro ridotte dimensioni ed il loro elevato rapporto superficie/volume che le rendono promotori chiave nella crescita di molti settori industriali e di ricerca. L’acquacoltura rappresenta il settore in più rapida crescita nell’industria alimentare a livello mondiale, contribuendo in modo significativo alla fornitura mondiale di pesce per il consumo umano. Per garantire una crescita sostenibile in grado di soddisfare le richieste del mercato globale, l’acquacoltura deve superare gli aspetti negativi legati alla sua stessa attività tra i quali, l’elevata concentrazione di composti organici nelle acque reflue non trattate, l’uso diffuso di antibiotici e la proliferazione di alcuni vettori di malattie. L’utilizzo delle nanotecnologie potrebbe offrire diverse soluzioni per risolvere tali problematiche permettendo uno sviluppo sostenibile dell’attività di acquacoltura. Grazie ad un approccio multidisciplinare che include analisi molecolari, chimiche e microscopiche, questo studio è stato in grado di testare l’utilizzo sicuro e innovativo di due diversi tipi di nanoparticelle in diversi settori dell’acquacoltura. Sono stati scelti diversi organismi modello (Danio rerio, Sparus aurata, Aedes aegypti e Escherichia coli) considerati come le specie più rilevanti ed utili per questa ricerca. Questa tesi di dottorato, ha evidenziato sia la grande versatilità sia il sicuro impiego di questi due tipi di nanomateriali per la risoluzione di diverse problematiche legate all’attività dell’acquacoltura. Tutti gli esperimenti sono stati condotti in ambiente controllato e ponendo le basi per studi futuri e possibili applicazioni pratiche nel settore dell’acquacoltura.
Nanotechnology has a great potential to create new materials with enhanced properties through the control and manipulation of the matter at the atomic and molecular level. Nanoparticles (NPs) play an important role in nanotechnology advances, unique NPs characteristics have accelerated the growth in the production of nanoscale materials and the rapid increase of their application in many areas. The major advantages of NPs are represented by their small size and high surface/volume ratio, which make them the key promoters of several industries and research sectors growth. Aquaculture represents the fastest growing food-producing sector in the world and significantly contributes to the world’s supply of fish for human consumption. In order to guarantee a sustainable growth that meets the global needs, aquaculture activity has to overcome some disadvantageous aspects deriving from its own practices, such as the high number of organic compounds in untreated wastewater, the large use of antibiotics and the proliferation of disease vectors. Nanotechnology application could offer different solutions to solve such issues and ensure the sustainable development of aquaculture activity. Thanks to a multidisciplinary approach that includes molecular, chemical and microscopy analysis, this study was able to test the innovative and safe application of two different types of nanotechnology on different aquaculture aspects. Different model organisms (Danio rerio, Sparus aurata, Aedes aegypti, and Escherichia coli) were chosen as the most relevant and useful species to the present research. This doctoral thesis highlighted at first, the great versatility and the safe application of these two types of nanomaterial to solve different aquaculture problems. All the experiments were conducted in a controlled aquatic environment laying the foundations for future studies aiming to a practical consequence in aquaculture activity.

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Cross, Stephen F. "Marine finfish and suspended shellfish aquaculture : water quality interactions and the potential for integrated aquaculture." Thesis, University of Stirling, 2005. http://hdl.handle.net/1893/1861.

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The objective of this study was to quantitatively document the culture performance and tissue quality of commercially important deepwater shellfish species (i. e., Pacific oyster, Crassostrea gigas; and Japanese scallop, Patinopecten yessoensis) cultured adjacent to marine finfish aquaculture operations, and to determine (from a production viability and seafood safety perspective) whether integrated finfish-shellfish Multi- Trophic Aquaculture (MTA), or polyculture, is a viable option for the aquaculture industry of temperate regions. Two study sites were employed for this research, one comprising an Atlantic salmon production facility and the other a Pacific salmonf arm. A 2-year assessment program for these sites detailed: (i) oceanographic and physiographicc haracteristics;( ii) organic waste flux, composition and dispersion; (iii) shellfish uptake and contaminant persistence; and (iv) shellfish culture performance. Organic waste flux ranged from 17.11 g/m2/day to 18.35 g/m2/day at the study sites. Phosphorus, calcium, carbon, zinc, cadmium, and strontium were waste constituents that were found at elevated levels at the farm sites with significant declines in concentrations with distance downstream (maximum effect to 100-115 meters). A mass balancee stimation suggested that 85.1% of the organic material (feed) entering the cage was used for fish growth/respiration, 6.8% was lost as settlable solids to the seafloor, and the remaining 8.1% was retained in the water column and a fraction that could affect non-target species (e. g., polyculture candidates) either directly or indirectly. A similar mass balance evaluation for trace metal and chernotherepeutic constituents indicated that 12.9% of the zinc, and an estimated 98.6% of the oxytetracycline contained in feed (during treatment), was released to the water column for potential uptake by co-cultured shellfish. The shellfish monitoring component of this study revealed that trace metal constituents of the feed did become available to the shellfish, although the quantifiable accumulation of trace metals in these non-target species occurred only in close proximity to the cage system and only for the tested scallops (Patinopectin yessoensis). Uptake rates of OTC by shellfish ranged from 0.056 - 0.100 ug/g/day with an associated clearance rate of 0.016 - 0.109 ug/g/day for the respective treatment periods. The comparison of uptake-clearance dynamics suggested asignificant seasonal component to these processes. The physical and biological processes affecting contaminant uptake and clearance rates were identified as important considerations in the management of a proposed integrated-MTA system. A simple Probable Effects Duration (PED) model was developed on the basis of Uptake-Clearance-Persistence plots, illustrating the basis upon which temporal effects of water quality deterioration could be managed in such a system. Shellfish growth was neither impeded nor enhanced as a result of being cultured directly within the influences of a salmon aquaculture facility. An organoleptic test demonstrated that shellfish palatability was not negatively impacted as a consequence of culture proximity to a finfish aquaculture facility. Results of this research suggested that two options are available for developing MTA in coastal temperate waters, i. e., an integrated MTA system and/or an adjacent MTA system. A wide range of MTA social, technical and economic benefits were identified and discussed as a result of this research. It was concluded that the development of a balanced MTA could add measurable environmental benefits to existing aquaculture systemss, setting the stage for future production efficiencies and growth. Given a proper regulatory framework, including seafood (MTA products) and environmental quality surveillanc, the potential water quality impacts on the shellfish component of a finfish-shellfish MTA (identified in this research initiative), and the associated risks over seafood safety, could be effectively managed to support this aquaculture evolution.

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Legault, Michel. "Détermination des répercussions de l'élevage en pisciculture du saumon atlantique (Salmo salar L.) sur son comportement et ses performances dans une rivière naturelle /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1985. http://theses.uqac.ca.

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Bélanger, Bernard. "Étude de certains aspects du développement larvaire chez le doré jaune (Stizostedion vitreum vitreum) /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1992. http://theses.uqac.ca.

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Zhao, Yanlai. "Integrated systems analysis for coastal aquaculture." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26824.

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This paper presents a model for the evaluation of coastal zone sites in conjunction with supporting decision making on the use of potential sites for aquaculture as well as other site activities including commercial fisheries, and as reserves for natural resources. The decision support model captures site specific data in the form of a geographical information system that overlays selected geographical regions with natural resource dynamics, habitat, commercial activities including aquaculture, and influence plumes including toxicology. Descriptive data for selected regions including system overlays and interactions are then evaluated to provide input to a multicriteria analysis that positions decision makers with respect to the relative importance of resources, habitat, commercial activities, and influence plumes. The model compares alternative evaluations of selected regions among diverse users., as well as providing a group decision evaluation procedure to assist in coastal zonal governance decision makers such as the awarding of fish farm site applications. The model is applied to the coastal zone of Grand Manan Island, New Brunswick situated in the Bay of Fundy.

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Robinson, Georgina. "Microbial-deposit feeder aquaculture bioremediation systems." Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3706.

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Edattukaran, Margaret P. "Aquaculture in the sultanate of Oman." Thesis, Boston University, 1999. https://hdl.handle.net/2144/28564.

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Boston University. University Professors Program Senior theses.
PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you.
This thesis is a story of Oman. It will lightly touch the rich fabric of Oman's history. It will chart through some of Oman's modernization as a cohesive Arab state into the new era under the reign of Sultan Qaboos bin Said. The thesis will emphasize Oman's potential as a young entrepreneur, and discuss the pathways and decisions made over the last two decades bringing Oman to the forefront of economic progress and social development while maintaining its cultural heritage. As Oman continues to look for revenue sources other than oil through industrialization, the thesis will focus on Oman's Fisheries industry and discuss the gradual depletion of its marine food resources--a consequence of over-fishing. The thesis will debate whether an aquaculture industry is the next step up from Oman's Fisheries sector and can Oman used the development of its aquaculture sector to increase its revenues. The analysis of an aquaculture sector for Oman will involve evaluating the economic, scientific, environmental and ecological factors dictating the success of entering this industry. It will focus on aquaculture of shrimp and the reasons why Oman would consider using this species to develop its aquaculture sector. The thesis will lay out various approaches to practicing sustainable aquaculture and focus on three potential options to develop the aquaculture sector. This section will canvass the critical factors that should drive the decision making process in selecting the optimal aquaculture approach that will yield Oman the revenue sources it seeks while minimizing any damage to the environment. The three choices are developed with an across the border measuring device with which Oman can evaluate the socio-economical and ecological pros and cons of selecting any of the three options.
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Franco, Sofia Cota. "Aquaculture of stalked barnacles (Pollicipes pollicipes)." Thesis, University of Newcastle upon Tyne, 2014. http://hdl.handle.net/10443/2631.

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The stalked barnacle, Pollicipes pollicipes, is considered a delicacy on the Iberian Peninsula and has a high market value. Despite being a dangerous activity, increased collection efforts and associated stock shortage have raised awareness of the need for effective conservation and stock management policies. Accordingly, aquaculture has received interest as an alternative to supply the market and for re-stocking programmes. However, knowledge on the aquaculture requirement of this species and applicable production cycles is limited. Research challenges span the entire P. pollicipes life cycle, from adult reproduction to larval settlement. Though adults have been kept in culture, the conditions required for broodstock reproduction and larval release remain poorly studied and larvae have been routinely extracted from wild-collected adults and reared to cyprids. Optimization of larval culture is essential for the production of high-quality larvae and avoidance of high mortality. Furthermore, cyprid settlement on artificial substrata presents a bottleneck to production, with settlement occurring mostly on conspecific adults. The conditions that mediate settlement on preferential substrata have yet to be established. Though juvenile behaviour and growth in the wild have been the subject of ecological studies, research on culture conditions is limited and the influence of environmental factors is poorly understood. In the present work, the effect of environmental conditions on the behaviour and development of P. pollicipes was tested throughout the life cycle to identify optimal culture conditions and assess potential for larger-scale culture. Research focused on broodstock reproductive conditioning, larval culture, larval settlement and juvenile culture and behaviour. Broodstock reproductive conditioning was investigated by monitoring larval production and nauplius quality from adults reared under different temperature regimes. P. pollicipes larvae were also cultured under different conditions of temperature, food quality, photoperiod and salinity, and monitored for growth and survival. Larval attachment and metamorphosis on adults were tested for cyprids of different age and batch, and according to environmental factors such as temperature, salinity, hydrodynamics and light conditions. Optimal conditions were then used for investigating settlement on substrata in culture, and natural and artificial structures were ii tested for settlement in the wild. Juvenile feeding behaviour and performance in culture were investigated in relation to hydrodynamics, temperature, food quality and quantity.

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Farzad, Razieh. "Novel Aquafeed Towards A Sustainable Aquaculture." Diss., Virginia Tech, 2018. http://hdl.handle.net/10919/103810.

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With World Health Organization estimation of population increase to over 9 billion by 2050, malnutrition and food insecurity are predicated to be two of the main challenges facing the world in the future. Fish is a source of protein that can have a significant contribution for solving the global food crisis. Fish for human consumption is provided by both the aquaculture industry and the capture fisheries, however, the flat-lined production of seafood from capture fisheries means aquaculture production should double in number to provide enough protein by 2050. Culturing fish at higher densities is being used as a way to increase the global aquaculture production. Modern aquaculture intensified practices expose the fish to various stressors that can negatively impact their welfare. Good nutrition can improve the health status of aquacultured fish while accumulation of specific nutrient can add value to the fillet. In line with that, the studies described in this dissertation aimed to examine the vital role of fish in human health and evaluate strategies to improve the sustainable aquaculture production of fish using novel aquafeeds. This was completed by conducting a survey of the essential minerals and heavy metals of commercially available catfish, salmon, and tilapia fillets in the United States marketplace and three fish nutritional trials to evaluate the impacts of novel aquafeeds on production and health of fish and the food quality of their respective fillets. Selenium with the established health benefit for human and fish was the trace mineral of interest in this dissertation. This element is the main component of a group of selenium containing proteins called selenoproteins that are antioxidant and maintain oxidative homeostasis of fish and human. Additionally, selenium is an antagonist for many heavy metals such as mercury. The market study revealed that catfish, salmon and tilapia samples available in United States marketplace are good source of selenium, zinc and phosphorous. The concentration of heavy metals in all the samples were lower than safety standards. Nile tilapia (Oreochromis niloticus) and rainbow trout (Oncorhynchus mykiss), which are two economically important aquacultured fish, were used as animal models in the fish nutritional trials. Different forms of selenium supplemented to Nile tilapia diet. The form of Dietary Se form did not have any significant (p>0.05) effect on growth, and plasma and hepatic GPX activity of Nile tilapia. However, organic selenium supplement showed significantly (p<0.05) higher bioavailability and accumulated in the fillets at the significantly higher concentration. In the second fish trial selenoneine, a novel selenium containing compound, was supplemented at various concentrations to rainbow trout diet. Other than growth parameters multiple other health biomarkers (lysozyme, glutathione peroxidase, superoxide dismutase activities) were examined to determine whether selenoneine supplementation had a positive impact on fish health. Selenoneine enriched diet significantly(p<0.05) increased the weight gain, lysozyme and oxidative enzymes activities of rainbow trout. Lastly rainbow trout feed was supplemented with commercially available probiotic (Actisaf), prebiotic (Safmmann), and their mixture (synbiotic). These dietary supplements did not have any significant effect on fish production but led to a significant increase in activity of oxidative enzymes in plasma when compared to control diet. These results suggest that feed supplements used in this dissertation can be used to promote the fish health raised in recirculating aquaculture systems and support an economically and environmentally sustainable aquaculture.
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Budhabhatti, Jennifer. "Integrating agriculture and aquaculture in Arizona." Diss., The University of Arizona, 1991. http://hdl.handle.net/10150/185676.

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This research project was designed to test the feasibility of growing catfish (Ictalurus punctatus) in cages at two densities in three types of irrigation waters in Arizona in 1989 and 1990. The types of waters studied were a pre-irrigation flowing water ditch, an irrigation return water sump and a pre-irrigation stationary water reservoir. Cages were designed for each type of water. The duration of the experiment was 76 days in 1989 and 117 days in 1990. Growth of fish was poor at both densities in pre-irrigation flowing water in 1989. Poor growth was probably due to the velocity of water and size variability of fish at stocking (coefficient of variability = 48%). Hand grading and the addition of baffles to cages resulted in increased growth and decreased size variability (25%) in 1990. Poor growth and low food conversion (5.2) were seen at both densities in irrigation return waters in 1989. Reduced growth and poor feed conversion were due in part, to wild fish bumping cages until food was lost. High variability in final weight (48.9%) was due to stocking of ungraded fish. In 1990, wild fish were removed from the pond and catfish were handgraded at stocking. These procedures resulted in higher final weights (660 g), lower conversion ratios (1.3) and lower size variability (31%). In 1989, poor growth and high size variation (55.4%) also occurred at both densities in pre-irrigation standing water. In 1990, grading fish at stocking and lowering stocking densities resulted in increased growth (570.6 g) and a lower coefficient of variability (28.7%). However, the food conversion ratio (2.6) was still high, due to food loss from cages, a disease outbreak and the associated mortality. Growing fish in all three types of irrigation waters appears to be biologically feasible. Fish in irrigation return flow waters had better growth rates than fish in flowing pre-irrigation water or in stationary pre-irrigation water. However, questions concerning the possible addition of contaminants to the system from agriculture effluent and the economics of integrating aquaculture into agriculture requires further study.

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McIntosh, Dennis. "Reducing the environmental impact of aquaculture." Diss., The University of Arizona, 2002. http://hdl.handle.net/10150/289234.

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Aquaculture has great potential to help supply the nutritional needs of a growing population. To date, however, the benefits that aquaculture can have, have largely been overshadowed by the environmental degradation some segments of the industry have caused. The following body of work describes my efforts to help reduce the environmental impacts of aquaculture. By integrating aquaculture production into traditional agriculture, the impact of farming on already limited water resources and the reliance on chemical fertilizers can be reduced. Recent expansion of the aquaculture industry in Arizona has made it possible to study the integration of olive groves with marine shrimp culture. In chapter 3, I describe the characterization and evaluation of the effluent from an inland, low-salinity shrimp farm as a potential source of irrigation water. I found that 0.41 kg of ammonia-nitrogen, 0.698 kg of nitrite-nitrogen, 8.7 kg of nitrate-nitrogen and 0.93 kg of total phosphorus (TP) were made available as fertilizer each day in the effluent water. Based on the results of this first study, I decided to conduct a farm trial to quantify the effects of these shrimp farm effluents on olive trees. This work is described in chapter 4. Trees in all treatment groups grew an average of 40.1 cm over the four month study period. While growth of trees irrigated with shrimp farm effluent did not improve in respect to the other treatments, our results do indicate that irrigating with low-salinity water had no noticeable negative effects. Chapter 5 describes work conducted in Idaho, as part of a larger study aimed at reducing the effluent loads of phosphorus (P) from high density, flow-through aquaculture facilities. Research steps were taken to establish a relationship between TP and the carbon 12/13 isotope ratio (δ¹³C) and/or the nitrogen 14/15 isotope ratio (δ¹⁵N). Our findings suggest that both δ¹⁵N and δ¹³C are good better proxies for P, after correcting for P retention. A linear regression of %P (corrected) on δ¹³C and δ¹⁵N resulted in R2 values of 0.843 and 0.8622, respectively. This suggests that by tracking δ¹⁵N and/or δ¹³C through a high-density, flow-through aquaculture facility over time I will be able to determine the residence time of P with a high degree of accuracy.

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MELIGRANA, MARINA CONCETTA TERESA. "A scientific contribution towards sustainable aquaculture." Doctoral thesis, Università degli Studi di Camerino, 2019. http://hdl.handle.net/11581/428746.

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The present PhD project has been made possible thanks to the support and collaboration of the major rainbow trout (Oncorhynchus mykiss, Walb.) farm in Europe. It was initially based on the original research proposal aimed at examining rainbow trout aquaculture in order to find alternative raw materials to be utilized in the formulation of feed for all the stages of breeding of this important salmonid. However, in 2017 the farm which funded the research project began rearing marine fish species in the Adriatic Sea and it was, therefore, decided to widen the scope of the study to include European gilthead sea bream (Sparus aurata, L.). During the course of the PhD triennium various activities relating to the above two species were carried out. With regard to rainbow trout, the first of the tree main studies focused on the effects on broodstocks of a diet which included materials of vegetable origin; the second assessed the supplementation of an innovative emulsifier into the diet of juveniles to improve the assimilation of lipids; the last one examined the qualitative traits of by products obtained by rainbow trout processing for their possible reutilization. In particular, a trial was carried out employing 4-year-old broodstocks of rainbow trout – both females and males – fed on a diet which totally substituted fish meal with vegetable meal and partially substituted (50%) fish oil with linseed oil. The effects of this diet, compared to a control diet containing fish meal and fish oil, were evaluated in terms of reproductive performances: quality of eggs, hatching and fingerling survival rate and mean body weight. Based on the results of this trial, it was possible to assume that feedstuffs containing vegetable protein and fat administered to broodstocks, negatively affected the quality of gametes and the progeny of rainbow trout. The second trial was performed in order to investigate the effects on the growth performance and feed conversion rate of diets supplemented, at two different doses, with a new emulsifier aimed at increasing lipid assimilation in rainbow trout juveniles. After 90 days of experimental feeding, the overall results of rainbow trout fed on the supplemented diets, can be considered satisfactory and within the normal range for the species size. Concerning the histology of the intestinal tract, a lower degree of irritation was observed in the trout fed on the experimental diets compared to those fed on the diets without the additive. The emulsifier supplemented in the feeds, resulted in beneficial effects together with a better welfare status of the rainbow trout. The research went on to consider the qualitative traits of by-products obtained by rainbow trout processing, including muscle meat and skin. This issue has become more pressing worldwide due to the ever-increasing amount of waste and wastewater. Recently, attention has been focused on the possibility of extracting precious nutrients from rendered fish proteins. In this study, the proximate composition and the fatty acid profile of rendered rainbow trout were evaluated and compared with the traits of the trimmed fillet. The results showed that rendered fish from rainbow trout processing still contains valuable nutrients, which could be successfully considered as possible feedstuff and also employed in various sectors and in innovative ways as, for example, in the production of finger food and fish burgers. Concerning sea bream, our research assessed the effects on the growth of juveniles of a partial substitution of fish meal with insect meal in their diet. Furthermore, the possibility of eliminating the use of antibiotics in sea bream rearing was also examined. In the last few years, insect meal has become one of the most studied sources of protein feedstuffs as an alternative to fish meal. A growing trial was performed in order to evaluate the efficacy of the inclusion of chironomid meal in the feed of gilthead sea bream juveniles. To this aim, samples of chironomid midges at larval stage were collected from aquatic environments, converted into meal and analysed from a qualitative point of view. Two experimental feeds with a different percentage of replacement were tested and compared to a control diet where the chironomid meal was absent. The experimental diets resulted in excellent palatability and led to satisfactory growth performances. The research also considered the possibility of rearing gilthead sea bream without the use of antibiotics. In recent years, the issue of antimicrobial resistance has become of prime importance at an international level. The possibility of rearing antibiotic free fish is the challenge we face in the twenty-first century. In this context, the company involved in this Eureka project, has decided to work towards the improvement of rearing techniques, biosafety and the management of environmental parameters, in order to reach high standards of animal welfare, from breeding to transportation and subsequent stages, in the hope that this will result in a successful battle against antibiotic-resistance. To this goal, a trial was performed monitoring the production cycle of gilthead sea bream that were farmed adopting an antibiotic free protocol in an offshore cage plant. Their growth performance, health status and flesh quality were then compared with conspecific wild fish. The antibiotic free sea bream were fed on a diet that contained not only raw materials of aquatic origin – which constituted the main source of essential fatty acids of the omega 3 series – but also those of vegetable origin, in full respect of environmental sustainability. There was a strong similarity between the morphometric parameters and somatic indices of the two fish groups of different origin. Moreover, the antibiotic free sea bream displayed a very low lipid fraction similar to that of the fish captured in the Adriatic Sea, which classified them in the category of lean fish. Data concerning the omega 3 content, demonstrated that the antibiotic free samples could be defined either as “Rich in omega 3”, or as an “Omega-3 source”.

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van, der Blom Daan Wilhelmus. "Aquaculture in Sweden : Sustainability of land-based recirculation aquaculture as a future alternative for Swedish fish farmers." Thesis, Linköpings universitet, Tema vatten i natur och samhälle, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-94683.

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With the world’s population expanding rapidly and estimated to reach nine billion in 2050, the demand for food will increase. Therefore the need for more sustainable ways of food production, in particular meat, poultry and fish are needed. Aquaculture can significantly contribute to this. This thesis focuses on Swedish aquaculture and in particular the increasingly used method of food fish farming in Recirculation Aquaculture Systems (RAS). The aim of the thesis is to analyze and discern the possibilities and challenges of RAS in Sweden, with particular focus on Östergötland. Furthermore it examines if and how aquaculture can contribute to an economical, social and ecological more sustainable Swedish aquaculture sector. The methods used are semi-structured interviews with stakeholders and actors at different governmental levels and fish farmers, participation in stakeholder meetings and literature research. The results show that Swedish aquaculture has overtime developed a negative image among consumers, politicians, government officials and investors. Today Swedish aquaculture faces threats that need to be addressed and opportunities that should be taken. In order to succeed with RAS in Sweden solid business plans, conservative production/ profit estimates and marketing are essential. Feed sources remain a concern from an environmental and economical point of view. Lack of financing from banks, investors and insurance companies, threatens Swedish aquaculture sector at the moment. Furthermore a lack of knowledge and capacity among lower government levels negatively influences aquaculture developments and this needs attention. The Östergötland region should concentrate on RAS and mussel farming and has the potential to become an example for the rest of Sweden. Aquaculture positively contributes to regional and rural development of the Swedish-country side by job creation and stimulation of local economies which is important for Östergötland and applicable to other regions of Sweden.

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Tiu, Laura G. "Assessment and Future Direction of The Ohio State University Aquaculture Program." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1276543251.

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Clausen, Rebecca J. "Social and ecological transformations of global marine fisheries /." Connect to title online (ProQuest), 2008. http://proquest.umi.com/pqdweb?did=1588418301&sid=4&Fmt=2&clientId=11238&RQT=309&VName=PQD.

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Thesis (Ph. D.)--University of Oregon, 2008.
Typescript. Includes vita and abstract. Includes bibliographical references (leaves 198-211). Also available online in ProQuest, free to University of Oregon users.

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23

Martins, Patrícia Tavares. "Molecular characterization of microbial communities in aquaculture." Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/16504.

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Doutoramento em Biologia
Microorganisms play key roles in fish production and in the maintenance of fish health in aquaculture systems. However, there is still a lack of fundamental knowledge regarding the bacterial composition and diversity of these systems. The general goal of this study is to gain fundamental knowledge on the bacterial communities of different aquaculture systems using molecular techniques. Furthermore, we evaluate the use of molecular methodologies to detect potential fish pathogens and develop a new molecular approach for early detection of a fish pathogen (Photobacterium damselae) in aquaculture systems. In the intensive aquaculture, we assessed the composition of bacterial communities inhabiting recirculating aquaculture systems (RAS) of turbot (Scophthalmus maximus) and sole (Solea solea). Both molecular approaches, DGGE profiles and barcoded-pyrosequencing of 16S rRNA gene fragments, revealed differences between the bacterial communities of both RAS, suggesting that the fish species being cultured promoted a strong effect on water bacterial communities. Several potential pathogenic species were detected, however despite the presence of these pathogens, no symptomatic fish were observed during the study. In this study barcoded pyrosequencing showed to be an unprecedented technique for assessing bacterial communities and reveal potential pathogens. In the second phase of this study, we investigated seasonal patterns of bacterioplankton (free-living and particleassociated bacteria) composition and their putative function in a semi-intensive European seabass (Dicentrarchus labrax) aquaculture system located at Ria de Aveiro. The results indicated that shifts in the bacterioplankton communities are driven by seasonal changes of abiotic characteristics of the estuarine water. Furthermore, the use of bioinformatics tools such as PICRUSt to predict metagenome functional content allowed us a better understanding of microbial quality in this aquaculture system. Given the impact of disease outbreaks in the development of aquaculture sector, we developed a new molecular approach for fast detection of Photobacterium damselae subspecies, responsible for major economic losses in the aquaculture systems in Mediterranean countries of Europe. Specific primers targeting the toxR gene were designed for overall quantification of P. damselae species and specific detection of its subspecies (P. damselae piscicida and P. damselae damselae) based on real time PCR (RT-PCR) and PCR denaturing gradient gel electrophoresis (PCR-DGGE), respectively. This approach showed good specificity for quantification and detection of P. damselae subspecies in estuarine and aquaculture water samples. The molecular approach developed here can contribute for a more effective long-term management of fish health in aquaculture systems.
Os microrganismos têm um papel fundamental no processo de produção de peixes, bem como na manutenção da saúde dos mesmos nos sistemas de aquacultura. Contudo, existe ainda falta de informação acerca da composição e diversidade bacteriana destes sistemas. O objetivo principal deste estudo é adquirir conhecimento fundamental acerca das communidades bacterianas de dois sistemas distintos de aquacultura (sistema intensivo e semiintensivo) recorrendo a técnicas de biologia molecular. Adicionalmente, avaliou-se também a utilização de técnicas de biologia molecular para detetar potenciais bactérias patogénicas e desenvolvemos uma nova abordagem molecular para deteção rápida de uma espécie bacteriana patogénica de peixes (Photobacterium damselae) em sistemas de aquacultura. Na aquacultura intensiva estudou-se a composição das comunidades bacterianas presentes num sistema de aquacultura em recirculação (RAS) com produção de pregado (Scophthalmus maximus) e linguado (Solea solea). As técnicas de biologia molecular utilizadas, eletroforese em gel de gradiente desnaturante (DGGE) e pirosequenciação de fragmentos do gene 16S, revelaram diferenças entre as comunidades bacterianas dos dois sistemas de produção, sugerindo que as espécies produzidas promovem um efeito acentuado nas comunidades bacterianas presentes na água. Várias espécies potencialmente patogénicas foram identificadas, contudo nenhum peixe demonstrou sinais de doença durante o estudo. Neste estudo, a pirosequenciação mostrou ser uma técnica sem precedente para estudar as comunidades bacterianas e revelar potenciais espécies patogénicas. Na segunda fase deste estudo, investigámos padrões sazonais na composição do bacterioplâncton e na sua função num sistema de aquacultura semi-intensivo de produção de robalo (Dicentrarchus labrax) localizado na Ria de Aveiro. Os resultados indicaram que as alterações nas comunidades do bacterioplâncton foram provocadas pelas variações sazonais dos fatores abióticos da água do estuário. Além disso, a utilização de ferramentas bioinformáticas para prever o conteúdo funcional do metagenoma, como o PICRUST, permitiu-nos conhecer melhor a qualidade microbiológica deste sistema de aquacultura. Tendo em conta o impacto dos surtos de doenças no crescimento do sector da aquacultura, desenvolvemos uma nova abordagem utilizando métodos moleculares para uma rápida deteção de subespécies de Photobacterium damselae responsávies por enormes perdas económicas em sistemas de aquacultura nos países mediterrâneos da Europa. Foram desenvolvidos primers específicos utilizando o gene toxR para quantificar a espécie P. damselae e detetar as suas subespécies (P. damselae piscicida and P. damselae damselae) utilizando a técnica de PCR em tempo real (RTPCR) e PCR – eletroforese em gel de gradiente desnaturante (PCR-DGGE), respetivamente. Esta abordagem mostrou elevada especificidade para a quantificação e deteção das subespécies de P. damselae em amostras de água provenientes de um estuário e de um sistema de aquacultura.

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Dlaza, Thembinkozi Steven. "Growth of juvenile abalone under aquaculture conditions." Thesis, University of the Western Cape, 2006. http://etd.uwc.ac.za/index.php?module=etd&amp.

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The aim of this research was, first to test the suitability of different seaweeds and formulated feeds as food for post-weaning juvenile South African abalone and secondly, to test the effects of basket design on the growth of grow-out juvenile abalone in both flow-through and re-circulation systems.

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Longdill, Peter. "Environmentally Sustainable Aquaculture: An Eco-Physical Perspective." The University of Waikato, 2008. http://hdl.handle.net/10289/2604.

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The New Zealand aquaculture industry during the late 1990s and early 2000s experienced a significant and sustained period of growth. Greenshell mussels (Perna canaliculus) are proving to be a popular and valuable cultured species, with large domestic and international markets. Traditionally, these bivalves have been farmed within enclosed embayments and on relatively small scales (~3 Ha). The recent expansion of the industry coupled with the near saturation of existing 'traditional' sites and new culture technologies has led the industry toward alternate environments, notably exposed offshore sites. Initial proposals within the Bay of Plenty have included multiple farms of ~4500 Ha each. This novel approach to shellfish culture created uncertainty with respect to potential environmental impacts, cumulative effects, and sustainable carrying capacities within these exposed open-coast locations. In zoning for Aquaculture Management Areas (AMAs), environmental managers must be informed of each of these aspects to ensure the rational and sustainable use of the coastal-marine space. The overall goal of this study is to determine the potential for environmentally sustainable large-scale offshore mussel culture within the Bay of Plenty marine environment. The long term sustainability of aquaculture development on an open coast is a function of many influences which can vary in both time and space. The benthic environments of the Bay of Plenty exhibit great variability in their ability to assimilate waste inputs from suspended mussel culture; a direct function of the variability in sedimentary environments and benthic habitats within the region. Specifically, silty sediments with low natural organic contents, generally found between 40 and 100 m depths are the most suitable locations for sustainable mussel aquaculture from an environmental impact perspective. Both observations and model predictions indicate productivity potential within the region to be greatest within neritic zones of the western Bay of Plenty. Local wind forcing is the predominant mechanism forcing local shelf currents. Current meter data and numerical modelling tests from this study indicate that local winds explain the majority of water current variability on the shelf, generate the delivery of new nutrients to the shelf through upwelling, and hence create the variability in productivity potential. Complicating the AMA zoning process for environmental managers, however, are existing uses of, and societal values toward, the coastal-marine environment. GIS planning tools have been shown to be effective at minimising conflicts and maximising sustainability potential through informed site selection. Within the Bay of Plenty, these preferential sites are located on the mid-shelf (60-80 m depths) offshore from Pukehina, Matata, and Whakatane. This study shows that the simulated cumulative lower trophic-level depletion impacts of two large (~5000 Ha) proposed offshore mussel farms vary seasonally as a result of subtle changes in ecosystem dynamics and mussel feeding patterns. At proposed stocking densities, largest relative impacts are expected during autumn and winter, when relative phytoplankton biomass is low and growth rates slow. During spring, while absolute impacts are greater than those during autumn/winter, greater phytoplankton-zooplankton biomass and faster growth rates result in quicker recovery times and reduced 'depletion halo' extents. Year-long predicted impacts are below those applied as 'acceptable limits of change', both within New Zealand and internationally, indicative of the ecological carrying capacity.

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Linnér, Johan. "Arctic charr growth regulators : implications for aquaculture /." Umeå : Swedish Univ. of Agricultural Sciences (Sveriges lantbruksuniv.), 2000. http://epsilon.slu.se/avh/2000/91-576-5778-5.pdf.

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ramezaniakhmareh, alireza. "Autonomous environmental monitoring probe for aquaculture sites." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for teknisk kybernetikk, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-20733.

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This project aims to develop an instrument that is capable of moving vertically in a controlled manner along a taut string from the sea surface to a predetermined depth while measuring pertinent seawater parameters. The main focus will be to specify, design and implement an embedded computer system that realizes the instrument.

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Clarkson, Alexander Ross. "The jurisdiction to regulate aquaculture in Canada." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/46455.

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Canadian aquaculture regulations need reform. Aquaculture regulations are constitutionally unsound and environmentally inconsistent. The federal government regulates aquaculture in British Columbia but the provinces regulate aquaculture in the Atlantic provinces despite the fact that similar provincial regulations were struck down as unconstitutional in British Columbia in Morton v British Columbia (Minister of Agriculture and Lands). No appeal court in Canada has ruled on the constitutionality of provincial aquaculture laws. As a result, provincial aquaculture laws are vulnerable to attack and aquaculturists face uncertainty. The environment also suffers from different environmental standards from province to province. In British Columbia, the federal government applies stringent disease and escapee regulations whereas in the Atlantic provinces disease and escapee regulations vary greatly. The purpose of this thesis is to clarify the scope of the federal and provincial legislative powers to regulate aquaculture. I conclude that the Morton decision interpreted the federal “sea coast and inland fisheries” power too broadly, incorrectly including net-pen aquaculture as a “fishery”. I then apply the pith and substance analysis to the provincial aquaculture laws impugned in Morton and I conclude that provincial escapee regulations are likely ultra vires but that provincial seafloor pollution regulations are likely intra vires. I also apply the pith and substance analysis to the aquaculture regulations in the Atlantic provinces and conclude that their property rights laws are likely ultra vires but their disease laws are likely intra vires. This review of escapee and disease regulations exposes unacceptable discrepancies in the standards between the provinces. In addition, I clarify jurisdictional issues that may arise regarding shellfish, plant, on-land, and offshore aquaculture. Finally, I critique the federal Pacific Aquaculture Regulations created in response to the Morton decision. I conclude that they lack transparency and they permit the release of deleterious substances that are, at the same time, prohibited by the Fisheries Act. By articulating the scope of legislative power relevant to aquaculture, this thesis defines a foundation upon which Canada and the provinces can build sustainable and consistent aquaculture regulations for future generations.

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Tollervey, Alan. "Algal nutrient uptake in recirculating aquaculture systems." Thesis, Heriot-Watt University, 1985. http://hdl.handle.net/10399/1651.

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Branfield, G. R. "Thermal charcteristics of a greenhouse for aquaculture." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019.1/1794.

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Thesis (MScEng (Mechanical and Mechatronic Engineering))--University of Stellenbosch, 2006.
Successful housing and breeding of exotic animals or plants often requires an environment that is quite different to the ambient conditions present. The current study approached the problem of sub-optimal water temperatures experienced by Central African Bream (Tilapia) housed within a South African greenhouse during winter months. A theoretical and experimental study of fundamental heat and mass transfer processes relevant to an aquacultural greenhouse was conducted. Experimental results were generally in agreement with those of previous researchers; while evaporation tests were found to concur particularly well with an analytical equation developed. The experimental results were used to develop a simple glass greenhouse model to evaluate the expected thermal behaviour during the coldest time of the year. Manipulation of the model revealed that water has the ability to absorb large quantities of solar radiation and regulate temperature fluctuations within such a system, and that the appropriate use of thermal insulation during both the night and day can maintain acceptable water temperatures for extended periods of time. With the conclusions drawn from the experimentation and modelling done, an optimised conceptual greenhouse design was presented, along with associated guidelines and principles for attaining the required water temperatures, and consequently providing the exotic fish specie with a healthy environment.

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Jaritkhuan, Somtawin. "Thraustochytrids as a food source in aquaculture." Thesis, University of Portsmouth, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343334.

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Anoh, Kouassi Paul. "Pêche, aquaculture et développement en Côte d'Ivoire." Nantes, 2007. http://www.theses.fr/2007NANT3001.

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Les questions relatives à la pêche et à l'aquaculture en Côte d'Ivoire ont fait l'objet de nombreuses études scientifiques et techniques, mais les problématiques développées ne permettent pas toujours de cerner toute la complexité du secteur de l'exploitation des ressources aquatiques. D'ailleurs, ces études n'évoquent que très rarement les interactions, pourtant nombreuses, entre ce secteur d'activité et le processus de développement. Cette thèse veut engager une réflexion sur les relations entre développement d'une part et pêche et aquaculture de l'autre. En travaillant à différentes échelles d'analyse (de la locale à l'internationale), l'objectif de la recherche est d'étudier : - les contraintes, les problèmes et les facteurs qui déterminent le développement de ces activités, - l'organisation des territoires de pêche, des structures aquacoles et les stratégies de gestion mises en oeuvre par les principaux acteurs, - l'impact des activités sur les sites qui les accueillent, en terme de peuplement, d'emploi, d'aménagement, d'urbanisation et de dévelopement, - les limites des pratiques de pêche et de production aquacole actuelles et les conditions de l'instauration d'une pêche et d'une aquaculture durables. Cette thèse qui s'inscrit dans une démarche de géographie sociale autour du concept de développement durable, s'int éresse aux relations entre la croissance économique, la gestion de l'environnement et l'équité sociale dans la pêche et l'aquaculture en Côte d'Ivoire.

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Vdovenko, Natalia. "Ukrainian aquaculture steady development in market economy." Thesis, Видавництво СумДУ, 2011. http://essuir.sumdu.edu.ua/handle/123456789/10279.

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Evans, Oliver Graham Evans. "Modeling the Light Field in Macroalgae Aquaculture." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1542810712432336.

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35

Oliveira, Rhaul. "Effects assessment of chemicals used in aquaculture." Doctoral thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/16297.

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Doutoramento em Biologia
Aquaculture provides food and income for millions of families worldwide being an activity with a high growth rate and with a strong potential for further expansion. Both producers and consumers are interested in a sustainable model of aquaculture development covering social, economic and environmental aspects. Such model implies to cope with the environmental impacts generated by aquacultures. The main objective of this work was to evaluate the use of chemicals applied in aquaculture farms and their harmful effects to aquatic organisms. Since more than 80% of global production of aquatic organisms is concentrated in Southwest Asia, special attention was given to the aquaculture in this region, particularly Thailand. Three different types of aquaculture scenarios were studied: shrimp farms and tilapia farms in cages and in earth ponds. Surveys and monitoring campaigns were conducted in several farms and the fate, use and application patterns of chemicals were identified. In cage farms the results indicated overuse/misuse of antibiotics, in shrimp farms the major group of chemicals used were disinfectants whereas in earth pond farms 1,7α-methyltestosterone (MT) was the most used. The results from the monitoring campaigns showed that the excessive use of chemicals was correlated to contamination of the surrounding environment namely with the antibiotics oxytetracycline (OTC) and enrofloxacin (ENR) in the cage farms, and with MT in the earth pond farms. In the laboratory, ecotoxicity assays were performed with antibiotics, disinfectants and pesticides using organisms belonging to different trophic levels. The disinfectants benzalkonium chloride (BKC), chlorhexidine gluconate (ChD) and glutaraldehyde (GA) were tested. BKC and ChD demonstrated to be very toxic to primary and secondary consumers. Moreover, an approach based on the species sensitivity distributions (SSD) was used to estimate the hazardous concentrations for 5 and 50 % of the species after BKC and GA exposure highlighting the sensitivity of primary producers to BKC exposure (HC5 = 10.8 μg/l). In the case of GA, different trophic levels showed similar sensitivities and a general HC5 = 300 μg/l was obtained. Additionally, a probabilistic environmental risk assessment was performed indicating a PAF (potentially affected fraction) of species > 5% for adverse effects of BKC in effluents and surface water. Concerning pesticides, both trichlorfon (TCF) and ivermectin (IVM) were studied. TCF showed to be extremely toxic to daphnids (48h- LC50 = 0.29 μg/l) and affected the acetilcolinesterase activity in D. magna and D rerio. IVM showed to be acutely toxic to D. rerio life stages (96h-LC50 = 18.5 μg/l for juveniles) and affected their development and biomarkers. In chronic exposures, IVM led to changes in the behaviour and growth of D. rerio juveniles (21d-LOEC < 0.25 μg/l). The antibiotics amoxicillin and OTC were not acutely toxic to aquatic organisms but both induced oxidative stress related enzymes of adults and embryos of D. rerio. Globally, most of the tested chemicals showed to compromise at least a particular group of organisms or sub-lethal parameters, requiring further long term studies so that the environmental risk assessment of these compounds can be refined. Lethal and sub lethal effects obtained to non-target organisms suggest a potential biodiversity loss in the aquatic ecosystems which might, thus, compromise the services provided by the ecosystems in a near future. Since the aquaculture relies directly on these services (e.g. high water quality) to succeed, there is an urgent need of control/education measures both in the use of chemicals in aquaculture and monitoring/mitigation of adverse impacts in natural ecosystems.
A aquacultura fornece sustento para milhões de famílias, sendo uma actividade em crescimento e com um forte potencial de expansão em todo o mundo. Há um interesse por parte de produtores e consumidores em desenvolver modelos sustentáveis de aquacultura abrangendo aspectos sociais, económicos e ambientais. Tais modelos implicam lidar com os impactos ambientais gerados pela aquacultura. O principal objectivo deste trabalho foi estudar o uso de produtos químicos usados nas aquaculturas e avaliar os seus efeitos nocivos para organismos aquáticos. Uma vez que mais de 80% da produção mundial de organismos aquáticos está concentrada no sudoeste da Ásia, foi dada especial atenção à aquacultura nessa região, particularmente na Tailândia. Três diferentes cenários foram considerados: aquaculturas de camarão, aquaculturas de tilápias cultivadas em gaiolas e em tanques escavados no solo. Em cada tipo foram realizados inquéritos e campanhas de monitoramento em várias aquaculturas nas quais foram averiguados o uso, destino e forma de aplicação de químicos. Os resultados indicaram o uso excessivo/inapropriado de alguns compostos, nomeadamente de antibióticos (em aquaculturas em gaiolas), de desinfectantes (em aquaculturas de camarão) e de 1,7α-metiltestosterona (MT) (em aquacultura de tilápias em tanques escavados). Os resultados das campanhas de monitorização mostraram que o uso excessivo de produtos químicos resulta na contaminação do meio ambiente com antibióticos (oxitetraciclina (OTC) e enrofloxacina (ENR)) nas aquaculturas em gaiola, e com MT nas aquaculturas de tilápias em tanques escavados. No laboratório, foram realizados ensaios de ecotoxicidade com antibióticos, desinfectantes e pesticidas usando organismos modelo pertencentes a diferentes níveis tróficos. Foram testados os desinfectantes, cloreto de benzalcónio (BKC), gluconato de clorexidina, e glutaraldeído (GA) sendo que os dois primeiros demonstraram ser muito tóxico para consumidores primários e secundários. Para uma análise integrada foi utilizada uma abordagem baseada nas distribuições de sensibilidade das espécies (DSE) com a qual se estimaram as concentrações perigosas (CP) para 5% e 50% das espécies após e exposição ao BKC e GA. O grupo dos produtores primários foi o grupo mais sensível à exposição ao BKC com CP5% = 10,8 μg/l enquanto para GA não foram encontradas diferenças de sensibilidade entre os grupos tróficos e, assim sendo, um valor geral de CP5% = 300 μg/l foi obtido. Além disso, uma análise probabilística dos riscos ambientais indicou uma fracção de espécies potencialmente afectada (FAPE) pelo BKC > 5% em efluentes e águas superficiais. Os pesticidas estudados foram o trichlorfon (TCF) e a ivermectina (IVM). O TCF foi extremamente tóxico para dafnídeos (48h-LC50 = 0,29 μg/l) e afectou também a actividade de acetilcolinesterase em D. magna e D. rerio. A IVM foi tóxica para adultos, juvenis e embriões de D. rerio (96h- CL50 = 18,5 μg/l para os juvenis) afectando o seu desenvolvimento e actividade de biomarcadores. Em exposições crónicas, IVM causou alterações no comportamento e crescimento em D. rerio juvenis (21d-LOEC <0,25 μg/l). Os antibióticos amoxicilina e OTC apresentam baixa toxidade para os organismos aquáticos, mas ambos induziram enzimas relacionadas estresse oxidativo em adultos e embriões de D. rerio. Em geral, a maioria dos químicos testados apresentaram toxicidade para algum grupo de organismo da cadeia trófica ou tiveram efeito a nível de parâmetros sub-letais, sendo portanto recomendados estudos de exposição crónica para que se possa refinar a avaliação de risco ambiental destes compostos. Os efeitos letais e sub-letais observados nos organismos não-alvo sugerem que pode haver uma perda da biodiversidade nos ecossistemas aquáticos, e assim, comprometer os serviços prestados pelos ecossistemas num futuro próximo. Sendo o sucesso da aquacultura dependente directo destes serviços (por exemplo, água de alta qualidade), há uma necessidade urgente de medidas de controlo/educação, tanto no uso de produtos químicos na aquacultura e monitoramento/mitigação dos impactos negativos destes nos ecossistemas naturais.

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Gonzalez-Alanis, Pablo. "The Inactivation of Pathogens in Aquaculture Systems." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/195899.

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As aquaculture has become a significant provider of the human diet, the interest to have better quality of sea and fresh products has been increasing. However the potential hazards associated with pathogenic agents resulting in losses to the industry are major concerns that provided the motivation for this study.The use of ultraviolet irradiation is an alternative to disinfect water in inlet and outlet water sources. However the ultraviolet disinfection method has some drawbacks including no disinfectant residuals and high cost of lamp fouling and replacement. The ultraviolet system needs to be calibrated according with the life time of the ultraviolet lamps.The MS-2 coliphage in this study is an approach to determine a good indicator for determining if an ultraviolet system can be effective in an aquaculture recirculation system. The susceptibility of this system can provide an indication if WSSV can be inactivated and possible other pathogenic agents.The WSSV experiment was successful in reducing mortality. Further studies have to be completed and analyzed before recommending for control of other pathogens.

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37

Brooks, George Benjamin Jr. "Dissolved Nitrogen Compounds in Integrated Aquaculture Effluent." College of Agriculture, University of Arizona (Tucson, AZ), 1992. http://hdl.handle.net/10150/208657.

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Integrated aquaculture utilizing pre- irrigation water will hypothetically increase the levels of dissolved nitrogen products in the resulting effluent. Research was performed to assess the levels of additional nutrients added. The results suggest however, that integrated aquaculture may reduce the amount of nitrogen as nitrate applied to the fields.

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Mateus, Lília Cristiana da Silva. "Phage therapy in aquaculture : use of phage cocktails and lysozyme." Master's thesis, Universidade de Aveiro, 2013. http://hdl.handle.net/10773/13268.

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Mestrado em Microbiologia
Aquaculture is one of the fastest growing food industry sectors in the world in recent years. However, the appearance of pathogenic microorganisms, including multirresistant bacteria, and their dissemination in the environment has become a problem for the aquaculture industry. This means that it is necessary to develop less harmful strategies to the environment to allow a sustainable growth of the aquaculture systems. Phage therapy emerges as a potential alternative to inactivate pathogenic bacteria in aquaculture. The main objective of this study was to assess the efficacy of phage therapy to inactivate fish pathogenic bacteria. The use of phage cocktails and lysozyme was also evaluated on the efficiency of phage therapy. The phage therapy assays were performed with the bacterium Vibrio parahaemolyticus and with three phages produced on this bacterium (VP-1, VP-2 and VP-3). The dynamics of phage-bacteria interaction was characterized in Tryptic Soy Broth through host and phage quantification, respectively by pour plate and by the double-layer agar technique. The three phages were tested alone and in cocktails of two or three phages. The efficiency of the bacterial inactivation by the phages was tested at different lysozyme concentrations (range 0.8 μg mL-1 to 20 mg mL-1). As the selection of bacteriophages is a key factor for the success of phage therapy, the host range, their survival in aquaculture water, as well as the burst size and the explosion time, were determined. The cross-infection was used to determine the phage host range. To determine the survival of the phages in marine water, the double-layer agar technique was used. The burst size and the explosion time were calculated by the one-step growth curve analysis. The use of cocktails of two and three phages was significantly more effective (reduction of 4 log at 2 h of treatment) than the use of the VP-1, VP-2 and VP-3 phages alone (reductions of about 0.6, 0.8 and 2.6 log, at 2 h of treatment respectively for the VP-1, VP-2, and VP-3 phages). The combination of phage plus lysozyme showed a better inhibitory activity when compared with the activity of the phage alone. The VP-1 and VP-2 phages were more efficient to inactivate the Vibrio (reduction of about 4 log after 6 - 8 h treatment), in the presence of high concentrations of lysozyme, than the VP-3 phage. However, the VP-3 phage was more efficient in the presence of low concentrations of lysozyme (reduction of 3.2 log after 2 h of incubation). The results of the cross-infection showed that the phages of Vibrio parahaemolyticus also infect Vibrio anguillarum and Aeromonas salmonicida with high efficiency. The assays of phage survival in aquaculture water showed that the phages remain viable for long time periods (more than 5 - 7 months). The VP-3 phage presented a higher burst size and a shorter latent period (42 and 40 min, respectively) than the other two phages (9 and 15 and 120 min and 90 min, respectively, for the VP-1 and VP-2 phages). In conclusion, the use of phage cocktails appears to be an effective approach to treat vibriosis. Bacterial inactivation is more efficient and occurs earlier when the phage cocktails are used, but their use in vitro does not prevent bacterial regrowth after treatment. However, the use of phage cocktails retarded the regrowth of the bacteria. The application of phages with lysozyme to eliminate or reduce fish pathogenic bacteria in aquaculture can be a promising strategy, namely when less effective phages are available. Besides, the use of phages with a high burst size and a short latent period clearly increase the efficiency of phage therapy.
A aquacultura é um dos setores da área alimentar que mais tem crescido nos últimos anos. No entanto, o aparecimento de microrganismos patogénicos, incluindo bactérias multirresistentes, e a sua disseminação no meio ambiente tornou-se um problema para a indústria de aquacultura. Este facto leva a que seja necessário o desenvolvimento de estratégias menos lesivas para o ambiente de forma a permitir o crescimento sustentável da aquacultura. A terapia fágica surge como uma alternativa potencialmente viável e eficaz para inativar bactérias patogénicas em aquacultura. O principal objetivo deste trabalho consistiu na avaliação da eficácia da terapia fágica para inativar bactérias patogénicas de peixes. Foi avaliado o efeito do uso de cocktails de fagos e de lisozima na eficiência da terapia fágica. Os ensaios de terapia fágica foram realizados com a bactéria Vibrio parahaemolyticus e com três fagos produzidos sobre esta bactéria (VP-1, VP-2 e VP-3). A dinâmica de interação fago-bactéria foi caracterizada em meio de cultura Tryptic Soy Broth através da quantificação do hospedeiro por incorporação e da quantificação dos fagos pela técnica da dupla camada de agar. Os três fagos foram testados isoladamente e em cocktails de dois ou três fagos. A eficiência de inactivação bacteriana pelos três fagos foi testada com diferentes concentrações de lisozima (gama 0,8 μg mL-1 a 20 mg mL-1). Como, para aplicar com sucesso a terapia fágica, é importante ter informação sobre as características dos fagos, a gama de hospedeiros, a sua sobrevivência na água da aquacultura, bem como o seu número e tempo de explosão, foram determinados. Para o estudo da gama de hospedeiros de bacteriófagos usou-se a infeção cruzada. Para determinar a sobrevivência dos fagos na água marinha foi usada a técnica da dupla camada de agar. O número e o tempo de explosão foram determinados através da determinação das curvas de crescimento síncrono. O uso de cocktails de dois e três fagos foi significativamente mais eficaz (redução de 4 log após 2 h de tratamento) do que o uso dos fagos VP-1, VP-2 e VP-3 sozinhos (redução 0,6, 0,8, e 2,6 log para os fagos VP-1, VP-2 e VP-3, respectivamente, após 2 h de tratamento). A combinação de lisozima e fago apresentou melhor atividade inibidora em comparação com a atividade do fago sozinho. Os fagos VP-1 e VP-2 foram mais eficazes na inativação bacteriana (redução de cerca 4 log após 6 - 8 h de tratamento) na presença de altas concentrações de lisozima do que o fago VP-3. No entanto, o fago VP-3 foi mais eficaz na presença de baixas concentrações de lisozima (redução de 3,2 log, depois de 2 h de tratamento). Os resultados da infeção cruzada mostraram que os fagos de Vibrio parahaemolyticus inoculados noutras bactérias infetaram também Vibrio anguillarum e Aeromonas salmonicida, apresentando uma eficiência de infeção elevada. Os ensaios de sobrevivência dos fagos na água de aquacultura mostraram que estes permanecem viáveis por longos períodos de tempo (mais de 5 - 7 meses). O fago VP-3 apresentou um número de explosão maior e um período latente menor (42 e 40 min, respetivamente), do que os outros dois fagos (9 e 120 min e 15 e 90 min, respetivamente, para o fago VP-1 e VP-2). Em conclusão, a utilização de cocktails de fagos parece ser uma abordagem eficaz para o tratamento de vibrioses. A inativação bacteriana é mais eficiente e ocorre mais cedo quando são usados os cocktails de fagos, mas a sua utilização in vitro não impede o recrescimento bacteriano após o tratamento, retardando, no entanto, o recrescimento da bactéria. A aplicação de fagos com lisozima, para eliminar ou reduzir bactérias patogénicas de peixes em aquacultura, pode ser uma estratégia promissora, nomeadamente quando os fagos disponíveis são menos eficientes. A utilização de fagos com um alto número de explosão e um período latente curto aumenta claramente a eficiência da terapia fágica.

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Luckhoff, Paul Daniel. "Application of the condition factor in the production of African sharptooth catfish Clarias gariepinus." Thesis, Stellenbosch : University of Stellenbosch, 2005. http://hdl.handle.net/10019.1/3421.

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Thesis (MPhil (Animal Sciences. Aquaculture))--University of Stellenbosch, 2005.
In recent years there has been a renewed interest in the commercial culture of African Sharptooth Catfish. Its robust characteristics and its air breathing capabilities makes the African catfish a good candidate for culture in intensive recirculating systems. In light of the size variation in offspring spawned from undomesticated fish, that may eventually increase cannibalism, suitable methods for the quantification of some production performance parameters such as growth and health measurements need to be established for application in intensive catfish culture. In fish the condition factor (CF) reflects information on the physiological state of the fish in relation to its welfare. This factor is expressed as Fulton’s condition index, or the K-factor. African Sharptooth Catfish fry with average weight of 1.9g ± 0.7867 and average length of 59.375mm ±8.812 were equally allocated into ten 1000L-recirculating tanks. The fish were fed a commercial feed to apparent saturation at a frequency of 5 times per day. Sixteen fish were sampled out of each treatment. Weight (g) and length (mm) of each fish were recorded every seven days over a trial period of 175 days from which Fulton’s condition index K was calculated. Results were analysed for significant differences using one-way ANOVA and Tukey’s pair wise comparison test for the various parameters. Growth parameters (a = -5.083, b = 3.004, R2 = 99.4%) derived from the logarithmic relationship between body weight (W) and standard length (L) indicated an isometric growth through the duration of the trail. No significant differences (P>0.05) in condition factors between treatments were found at the beginning of the trail. Significant differences (P<0.05) were found at the end of the trail for weight between ponds and condition factor between treatments. No significant difference (P> 0.05) between length and treatments were found at the end of the trial. Mean condition factor was 0.856 ± 0.187. By using this information on condition factor for African catfish a K-factor calculation chart for African catfish could be calculated, to be used as a practical measurement tool to measure performance goals on catfish farms.

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Chen, Yrong-Song. "Waste outputs and dispersion around marine fish cages and the implications for modelling." Thesis, University of Stirling, 2000. http://hdl.handle.net/1893/26683.

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Aquaculture plays an increasingly important role in food production as the catches of wild fish stocks continue to decline on a global scale through overfishing. However, the rapid development of intensive cage aquaculture in particular, which requires high inputs of energy, food and capital, can result in adverse effects on the environment. While spatial distribution and sediment loading models for particulate wastes from marine fish cages have been under development for more than 10 years, the models still contain numerous assumptions that limit their usefulness. These include the use of very limited data for fish feed and faecal pellets sinking rates that take no account of food manufacturer, type or size or environmental conditions. The present study provides information on a range of pellet types for three of the most important European farmed fish species (i.e. Atlantic salmon Salmo salar L., sea bream Sparus aurata, sea bass Dicentrachus labrax) that may be readily incorporated into models. Such data, combined with validation of predictions through in situ field investigations is designed to help improve the accuracy and usefulness of solid waste dispersal models. The studies comprise four main sections, i.e., quantifying food and faecal pellet characteristics, examining nutrient leaching rates from uneaten food and fish faeces, determining resuspension characteristics of uneaten food, modelling of solid wastes dispersion and thus the development of environmental tools. Existing literature relating to environmental impacts of cage aquaculture is reviewed and the key factors highlighted. Two preliminary studies provided information on the influence of gravity acceleration on settling velocity determination and appropriate techniques for monitoring the rate of nutrient leaching from faecal wastes. Settling velocities of Atlantic salmon diets were significantly greater at 20 psu salinity than at 33 psu and significantly higher for most pellet types at 10°C than, at 20°C. Settling velocities for unsoaked salmon diets were found to increase with pellet size, from a mean of 5.6 cm s-1 for the smallest pellet (2 mm) to 13.9cm s-1 for the 10 mm standard (20 to 24% fat) pellets. Settling velocities of extruded diets for sea bream and sea bass diets ranged from 3.9 to 10.6 cm s-1, broadly similar to those for salmonid diets. Settling velocities of salmon pellets were not significantly affected by immersion time (0 - 15 min). Given the water depths at fish cage sites and the settling times involved, it is concluded that it is unnecessary to take account of changes in food pellet settling velocity as a result of immersion. Freshly net-collected salmon faecal pellets appeared to consist of fine solid material approximately the size of the formulated diets. The range of salmon faecal settling velocities was 3.7 to 6.2 cm s-1 (mean = 5.3 cm s-1) at 15°C and 33 psu. There are no significant differences in nutrient leaching of carbon and nitrogen from all six salmon diets after 20 min immersion in sea water. However, a rapid loss of faecal nutrients occurred 2.5 to 10 min after immersion in sea water. Total C and total N were found to leach by as much as 22% and 26%, respectively, after 5 min immersion during one sampling occasion. Experiments conducted in a large-scale flume tank showed the critical resuspension velocities of a range of commercial fish feeds were between 8.63 cm s-1 and 9.53 cm s-1. Above the critical resuspension speed, pellets moved by saltation, i.e. traveling along the sediment by rolling, sliding or hopping on the bed. The velocities of pellet resettlement ranged between 0.79 cm s-1 and 3.98 cm s-1 under the critical resuspension speeds. Field trials, involving the deployment of sedimentation traps, showed a general relationship between sedimentation of material and distance from cages, i.e. more sedimented material was associated with sampling sites closest to the cages. The spatial changes in sedimentation rates in the first trial were between 15.4 and 31.7 g DW m-2 d-1 at 30 m and 10 m stations, respectively. Values in the second trial (38.5-65.5 g DW m-2 d-1) were twice those in the first trial, but followed the same pattern. The model presented in this thesis is a combination of a spreadsheet model (Microsoft Excel 6.0) and Surfer plot program (Golden Software Ltd., ver. 6.04). Excel is used to prepare basic mathematical operations behind the model, including a mass balance submodel and use of a formula for calculating dispersion of uneaten food and faeces on the sea bed developed by Gowen et al. (1989). The operation of the waste dispersion model for marine cages takes into account the various settling characteristics of waste particles. It was verified with a set of in situ sedimentation data obtained from the field trial described above. Results described the waste dispersal around the vicinity of the cage farm. For the future, it is intended that further validation and optimisation of the model will be carried forward by a combination of both increasing user involvement and incorporation of data from comprehensive studies as these become available. Together, these will contribute to reducing and remedying the environmental impacts of future development.

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Hunter, Donna-Claire. "A GIS-based decision support tool for optimisation of marine cage siting for aquaculture : a case study for the Western Isles, Scotland." Thesis, University of Stirling, 2009. http://hdl.handle.net/1893/2332.

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Scotland’s coastal environment has many areas which are potentially suitable for sustainable aquaculture development. However previous studies have shown that aquaculture may have a detrimental impact on sensitive environments. The main objective of this study is to develop a holistic management tool for sustainable coastal marine aquaculture in the Western Isles of Scotland through development of a multi-faceted holistic model that allows consideration of sensitive environments. As the Scottish Government promotes better collaboration and integration of all involved in coastal zone governance (Baxter et al, 2008) this study illustrates the benefits to be gained from harmonized management of information in a Geographical Information System. GIS models are strong support tools designed to aid decision-making. The main strengths are that GIS can generate easily understandable visual displays of results which are based on robust models capable of incorporating vast amounts of spatial data and which can be predictive and can simulate future coastal environment scenarios. Within this study it is demonstrated that GIS-based models can successfully manage and manipulate a wide range of datasets that are essential components in the determination and management of suitable aquaculture locations. The GIS decision support tools evaluated and integrated in this study were based on four main sub models. These were Cage Site Suitability, Particulate Dispersion, Sensitivity Biodiversity Indicators and Visual Landscape Capacity. Exploration of a combination of these sub-models into an overall decision support system was also completed. All sub models developed were flexible, instrumentally coherent and communicatively balanced for the management and planning of the coastal environment . A sub-model was designed to evaluate and optimize the location of marine cage systems. This required development of data layers and modelled sub-components relevant to the important environmental and engineering factors affecting cage designs which included wave climate, bathymetric and substrate profiles. Three cage types were explored; those designed for sheltered, semi-exposed and exposed areas. These environmental factor layers were combined through weighting and Multi criteria evaluation consideration for each cage type. The resulting three sub-models indicated that while the archipelago has quite restricted development potential for cages designed for sheltered environments (91km2), there is a limited development potential for cages designed for semi exposed environments (1543km2) and an optimal potential for aquaculture development with cages designed for exposed environments (3103km2). The greatest potential environmental impact from aquaculture comes from particulate dispersion. Currently, assessing footprints of effect from fish farms is carried out on an individual site basis mostly at ten metre resolution. The sub-model successfully developed in this work resulted in a partially validated multisite particulate sub model at one metre resolution which implemented maximum current velocity as the friction/force image. The sub-model was run on a range of coastal loch fjord systems and demonstrated the variation in particulate dispersion patterns in each fjord system. In all the fjord systems modelled, even where farm sites are close neighbours, there appears to be minimal interaction in the particulate dispersion. While the particulate sub-model is effective and rapid to deploy for multiple sites, it requires further development in order to incorporate the quantitative aspects of particulate dispersion. Aquaculture biodiversity sensitivity indicators were evaluated and five main sub-components were developed; Species sensitive to Aquaculture, Endangered species, Species important to the Western Isles, important spawning and nursery areas and Protected Areas. The sub-model was constructed by combining these layers through weighting and Multicriteria evaluation. The outcomes indicated that within the study area there are 1168km2 (4% of study area) which are highly sensitive to aquaculture activity, although 20595km2 (65% of study area) has a biodiversity that is much less sensitive to aquaculture. This sub-model, and some of its components, can operate as a “stand alone” tool or can be combined into a larger framework. Little modification and re-parameterisation would be required to enable models to be developed to cover the whole of the Scottish coastline, or other coastal locations. Aquaculture can visually affect landscapes, seascapes and can adversely affect visual capacity of different areas. GIS was successfully applied to investigate this contentious issue. This comprehensive and flexible sub-model successfully develops Seascape and Landscape sensitivity analysis of aquaculture structures and also incorporated a novel approach to visual assessment through use of proportional assessment. Combining the sensitivity layers, 6448km2 of the waters of the archipelago (20% of study area) were categorized as having high capacity to incorporate new aquaculture developments, whilst 3301km2 (10% of study area) have a moderate capacity for new aquaculture structures and 1324km2 (4% of study area) have a low capacity for new developments. An overall conceptual framework was designed to explore two methods for the combination of the major sub-models in order to identify the most appropriate areas for sustainable aquaculture with consideration of possible conflicts including conservation issues. Initial evaluations involved the extraction of information from the component GIS sub-models into a structured database. The extracted data provides a range of information that can be used for statistical analysis and decision support, but which leaves the evaluation of the optimal siting of aquaculture at any location in the Western Isles in the hands of the database interrogator. The second method involved combining the sub-models within GIS whole considering trade offs in relation to conservation. This GIS combination of models indicated that, taking many factors into consideration, the Western Isles has 748km2 (2.5% of study area) appropriate for aquaculture development when implementing the C315 and whilst considering the interactions with conservation areas. There were 498km2 (1.6% of study area) appropriate for development when implementing the intermediate C250 cage types but only 15km2 (0.04% of study area) were appropriate for development based on the LMS cage designs for sheltered environments. Both analytical approaches had strengths and weakness and clearly both need to be used in combination to maximise the benefit of the GIS model outcomes. This study has demonstrated the ability to apply scientific rigour to spatial modelling of aquaculture problems including site suitability, biodiversity, landscape capacity and multi-site particulate dispersion. The various sub-models and their components sub-models can be stand-alone decision-making tools or combined into a holistic model which incorporates a flexible method of trade-off management. The range of GIS-based coastal analytical tools developed form the core of a decision support system that can enable the objective management of the increasing demands on the coastal zone, while having the capacity to bring together stakeholders, multiple agencies and governing bodies that are responsible for management and use of these precious and sometimes threatened resources.

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42

Du, Plessis Darren Scott. "Chemosensory properties of different Ulva extracts and their effects on Tripneustes gratilla." Bachelor's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/12766.

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Includes bibliographical references.
Identifying the chemical compounds that attract urchins to seaweeds will increase sea urchin aquaculture efficiency as these compounds can be utilized in the production of artificial feeds enhancing their attractiveness and palatability. This study investigated the chemosensory preferences of the tropical sea urchin Tripneustes gratilla for four crude extracts of Ulva as well as Fresh Ulva and an artificial feed. The four crude extracts of Ulva (Methanolic, Ethanolic, Chloroform and Chloroform-Methanol extracts) were tested by pair-wise chemosensory trials in a Y shaped maze. Urchins were significantly deterred by both the Chloroform and Chloroform- Methanol extracts as well as the solvent controls and artificial feed, however T. gratilla was significantly attracted to both the Methanolic and Ethanolic extracts. These two extracts were tested individually against Ulva and the urchins could not distinguish between Ulva and the extracts. When these two extracts were tested against one another it was found that the urchins were significantly attracted to the Methanolic extract. The Methanolic extract was then added to the artificial feed and significantly improved the feeds attractability. This indicates that these extracts, or the compounds which are responsible for this effect, can be incorporated into artificial feeds thereby making them more attractive to the sea urchin. The percentage yield of Ulva that each solvent extracted was different, although only the Ethanolic extract was found to be significantly different from the Chloroform and Chloroform-Methanol extracts. Future studies are needed to examine the chemical composition of these specific chemosensory compounds. By incorporating these attractive extracts into artificial feeds, South Africa can potentially improve the cultivation success of T. gratilla therefore expanding the economy of the local aquaculture industry through the export of this highly valued seafood product.

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Ginindza, Nhlanhla Joseph. "Effect of lipid inclusion levels in aquafeed on carcass composition, quality change during storage and nutrient excretion in dusky kob (Argyrosomus japonicus)." Thesis, Rhodes University, 2016. http://hdl.handle.net/10962/d1020854.

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Dusky kob, Argyrosomus japonicus, is an aquaculture species in South Africa that is in pilot commercial production. While the major nutrient requirements of the species are known, the advantages of incorporating formulated feeds into the diet of the species has yet to be fully explored. Research on formulated feed composition is required to: minimise input costs; improve the organoleptic properties and meat quality; and minimise nutrient loss, which contributes to environmental pollution. This study sought to test the impact of different lipid levels in aquafeeds fed to dusky kob juveniles by determining: (i) growth performance, feeding efficiency, proximate and fatty acid composition; (ii) chemical changes and shelf-life of refrigerated fish fillets; and (iii) metabolic rates and nitrogen excretion of juvenile dusky kob. And more...

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Lazo, Zamalloa Oxana. "Development of new products from aquaculture fish species." Doctoral thesis, Universitat de Girona, 2018. http://hdl.handle.net/10803/471460.

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Europeans are regular consumers of fish and aquaculture products. Therefore, five species of potential aquaculture rearing named: Meagre, Pikeperch, Grey Mullet, Greater Amberjack and Wreckfish were selected for new product development. This work incorporated opinions of both experts and naïve assessors thus, including specific demands and consumer preferences, in selected markets of the European Union (UK, Germany, Spain, France and Italy). Different fish product prototypes were developed from the fish species accordingly with suggested ideas and based on the physicochemical and sensory properties of the selected species. Six of these products were chosen, based on their level of processing and addressed market. Consumers perception of all six of them was also assessed in the five selected countries. As it turned out the image/perception of the different products, differed in an important way between countries, as well as their impact on the product acceptance and purchase probability
Los pasíses de la Unión Europea son consumidores habituales de productos de acuicultura. Es por ello que, se seleccionaron cinco especies con potencial acuícola: Corvina, Lucioperca, Mújol, Seriola y Cherna para el desarrollo de nuevos productos. Este trabajo incluyó opiniones tanto de expertos como de consumidores habituales, incluyendo asñi demandas específicas y preferencias en mercados seleccionados de la UE (Alemania, España, Francia, Italia y Reino Unido. Se desarrollaron distintos prototipos de productos basados en ideas sugeridas y en las propiedades fisicoquímicas y sensoriales de las especies. Seis de estos fueron seleccionados basados en su nivel de procesamiento y mercado. La percepción de consumidores sobre los productos fue evaluada en los 5 países de la UE.La percepción de la imagen de los productos difirió notablemente entre países, así como en la aceptabilidad e intención de compra

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Cordero, Francisco Javier Martinez. "Regional economic planning of shrimp aquaculture in Mexico." Thesis, University of Hawaii at Manoa, 2003. http://hdl.handle.net/10125/995.

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Aquaculture plays a critical role in alleviating demand pressures caused by increasing fish consumption and over-exploitation of fishery stocks. While aquatic foods are generally considered low-revenue generators in comparison to other protein-sources, aquaculture products help to support food security, income, and higher standards of living, particularly in developing countries. Decision makers, i.e. policy-makers and farmers, are challenged with the responsibility of planning and conducting aquaculture development in a sustainable way whereby social, environmental and economic goals are simultaneously satisfied. Existing studies that economically evaluate the industry for its current and historical performance, and future development scenarios are invaluable to sustainable planning, but have not been developed in Mexico. This dissertation is comprised of two essays applying Economics and Operations Research theory to regional economic planning for the sustainable development of shrimp farming in northwest Mexico. The analyses are carried out both at the micro (farm) and macro (industry planning and development) levels based on an unbalanced panel of shrimp semi-intensive farms containing primary-source information at pond level for the period 1994, 1996-1998. Using an input distance function approach, the first essay examines total factor productivity (TFP) and technical efficiency (TE) using both traditional (T) and environmentally-adjusted (EA) indicators. The reduction in TFP was determined to be due to a technological regression as reflected by increased input-intensive production technology resulting in an increase in undesirable outputs. The learning curve resulting from a shift from white shrimp to blue shrimp production species resulted in higher FCRs, water exchange and pollution emissions, despite increasing shrimp yields. In all years except 994, EA TE and EA TFP were lower than the traditional TE and TFP scores. TE and TFP had an opposite behavior than yields in this period of time. In order to improve the technological change (TC) component of TFP in light of stable TE scores, increased government assistance in disseminating technological know-how is necessary to improve TFP at a faster rate during the transition period. A sensitivity analysis also revealed the economic feasibility of the implementation of pollution abatement technology based on the calculated shadow price of N and P pollutants at USD $6.35/kg and $8.3/kg respectively. In the second essay, a multi-criteria decision making (MCDM) model was developed to evaluate the sustainable development of shrimp farming in the northwest region of Mexico (States of Sonora, Sinaloa and Nayarit) based on government objectives for aquaculture development in Mexico. Three possible production systems among two species were investigated. The optimal combination of new shrimp farms within 22,500 ha over a five-year period is determined. The planning objectives assumed in the MCDM model are maximization of employment (E), foreign exchange earnings (XG), and economic rent (ER), and total pollution (TOTALPOLL) minimization, subject to land availability and local market demand constraints. Under a preliminary evaluation of single objective optimization, XG and ER maximization produce similar results: USD $888.6 and $322.5 million in foreign exchange earnings and economic rent respectively, and the creation of 6,150 jobs. The MCDM model was implemented using Feasible Goals, which allows for the simultaneous graphical evaluation of decision maps arising from trade-offs among efficient solutions. When fully allocating the available land (22,500 ha), the multiobjective development of the shrimp farming industry produces 7,490 new jobs, ER and XG of USD $204.5 and $497.6 million respectively, with a total pollutant discharge of 2,000 tons. The multiple-criteria optimization strongly favors semi-intensive systems (93% of the total 466 new farms), producing 57,119 tons of shrimp by 2005. The sustainable development of the industry based on the assumptions of this analysis does not suggest intensification of systems. Rather, the results of the MCDM analysis support the claim that semi-intensive farms, which are more common in Mexico, promote sustainability. Based on the findings of each of the essays, it is suggested that production performance indicators are needed on a periodic basis for the evaluation of the shrimp industry of Mexico. Production performance measurements may better assist farmers in the decision-making for industry sustainability and growth. Moreover, direct determination of N and P discharges by farms are recommended in future studies as well as incorporating risk and employing longer time series.

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Xu, Zinan. "Isolation, characterisation and application of bacteriophages in aquaculture." Thesis, University of Stirling, 2016. http://hdl.handle.net/1893/23740.

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The increasing incidence of infections due to antibiotic resistant bacteria has led to renewed interest in bacteriophages (= phages) and phage therapy. Although phage therapy has been applied to control bacterial diseases in plants, poultry, livestock and humans, its application in aquaculture is still relatively limited. The emergence of phage-resistant bacterial mutants has been considered to be one of the major limitations of phage therapy. This study aimed to (i) isolate and characterise phages; (ii) select phages and their bacterial hosts to set up in vivo phage therapy models with aquaculture animals, and estimate the efficiency of phage therapy; (iii) investigate the generation and characteristics of phage-resistant mutants, and thus estimate the consequence of applying phage therapy when phage-resistant mutants emerge; and (iv) discuss the prospects for application of phages in aquaculture. Two Vibrio isolates and their phages were isolated from a Scottish marine fish farm. Based on the results of conventional phenotype testing and 16S rRNA gene sequencing analysis, the two vibrios, V9 and V13, were identified as Vibrio splendidus and Vibrio cyclitrophicus, respectively. The bacterial characteristics including morphology, temperature and salinity range of growth, production of extracellular enzymes, and the possession of virulence genes were examined. According to the morphological characteristics observed using transmission electron microscopy by negative staining, phage PVS9 of V. splendidus V9 was identified as a myophage, while phage PVC13 of V. cyclitrophicus V13 was identified as a siphophage. The phages could only lyse one bacterial host strain and their genomic DNA was double stranded with a size of ~46 kb. The two Vibrio isolates were found to be non- or of low virulence to rainbow trout, goldsinny wrasse and Artemia in pathogenicity experiments. Thus an in vivo phage therapy model could not be set up using these Vibrio isolates and their phages. Two phages pAS-3 and pAS-6 were isolated using the Aeromonas salmonicida subsp. salmonicida Hooke strain as the host. Phages pAS-3 and pAS-6 had a similar genome size of ~50 kb, and the same relatively narrow host range within A. salmonicida subsp. salmonicida strains. The siphophage pAS-3 formed clear plaques and inhibited A. salmonicida Hooke growth in vitro completely for at least 18 hours when using MOI = 1,000, whereas the podophage pAS-6 formed turbid plaques and weakly inhibited Hooke growth. Rainbow trout exposed by intraperitoneal injection with 0.1 mL of the raw phage preparations at a concentration of 108 PUF mL-1 showed no adverse effects over 14 days. In the phage therapy trial, fish were firstly injected with 1 x 102 CFU fish-1 of A. salmonicida Hooke, then immediately injected with phage preparations of pAS-3 and pAS-6, respectively, using MOI = 10,000. Compared with the control group (which did not receive phage treatment), phage treated groups showed a delay in the time to death, and lower mortalities. However, the mortalities and time to death between phage treated and non-treated groups were not significantly different. Phage-resistant mutants of pathogenic A. salmonicida strain Hooke were induced by repeatedly challenging with phage pAS-3. One of the mutants, termed HM, was chosen to compare the characteristics with the parental wild-type strain Hooke. Test results including the formation of ‘smooth’ colonies on TSA, autoagglutination negative, the formation of creamy colonies on Coomassie Brilliant Blue agar, and the degradation of a thick/furry layered structure on the cell surface indicated a deficiency of the A-layer in the phage-resistant mutant HM. Therefore, it was deduced that the A-layer either directly acted as the receptor of A. salmonicida phage pAS-3, or was affected indirectly by the change of an unknown phage receptor. The greater wax moth larvae model was used to compare the virulence of the phage-resistant mutant HM and the parental wild-type strain Hooke, as it is an ethically acceptable animal model, which has the advantages of being low cost and convenient for injection, and is also a recognised alternative model for bacterial pathogens of fish. The results showed that virulence of the phage-resistant mutant HM did not decline in the greater wax moth larvae model compared with that of the parental wild-type strain Hooke. In conclusion, different approaches were used to isolate and characterise phages from different aquaculture environments for potential use in phage therapy. A rainbow trout model was set up using pathogenic A. salmonicida strain Hooke and two A. salmonicida phages pAS-3 and pAS-6. The use of phage treatment led to lower cumulative mortalities and delay to the time of death, although the differences between the groups were not significant, futher work is required to determine if these phages have potential in phage therapy. The consequence of applying phage therapy when phage-resistant mutants emerge was estimated based on their characteristics and virulence, and no decline in virulence of the phage-resistant mutant from this study indicates the importance of fully testing the virulence of phage-resistant mutants before carrying out large scale field trials of phage therapy. It appears feasible to use phage therapy as an alternative approach to control bacterial infections in aquaculture, but further studies are required to focus on improving effectiveness, and also to overcome the concrete limitations and hurdles in application and commercialisation. Moreover, a broader range of applications of phages in aquaculture should be explored.

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Britz, Peter Jacobus 1959. "Adventures with abalone : aquaculture, poaching, and fishery restoration." Rhodes University, Grahamstown, 2011. http://hdl.handle.net/10962/d1018943.

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[From the text] Tonight I am going to tell you about my research on a another mollusc, the humble abalone. - In contrast with the highly evolved squid, this marine snail belonging to the ancient archeogastrod lineage which has a much simpler anatomy and lifestyle. It doesn’t posses a proper brain mass, only having 4 ganglia or nerves knots at the front end. Its two simple eye spots which detect light and dark, a tough shell and a large and extremely powerful foot muscle to adhere to rocks. This simple configuration has served well for over 100 million years.

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Dorrington, Tarquin. "Recombinant antimicrobials for feed based delivery in aquaculture /." View online ; access limited to URI, 2005. http://0-digitalcommons.uri.edu.helin.uri.edu/dissertations/AAI3188058.

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Gamboa-Delgado, Julian. "Application of natural stable isotopes in aquaculture nutrition." Thesis, Bangor University, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.505985.

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Duckworth, A. R. "Aquaculture of sponges for production of bioactive metabolites." Thesis, University of Canterbury. Zoology, 2000. http://hdl.handle.net/10092/6672.

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Sponges have proved to be the best source among marine organisms of biologically active metabolites for use as drugs or biomedical tools. If successful in clinical trials, bioactive metabolites will be needed in vast quantities, but most sponges contain only trace amounts of them. Of the supply methods currently being examined, aquaculture is considered to be the most cost-effective or perhaps the only method to guarantee sufficient supplies of some sponge metabolites. Two factors restricting the commercial development of sponge aquaculture are a poor understanding of how the environment affects the growth, survival and metabolite biosynthesis of sponges, and the lack of a farming structure that can supply sufficient quantities of bioactive metabolites. This study examined these factors focusing on two species, Latrunculia brevis and Polymastia croceus, both of which contain metabolites with biomedical application. For three years the population dynamics, growth and bioactivity (measure of metabolite biosynthesis) of wild L. brevis and P. croceus were examined to further our knowledge about sponge ecology and also to provide information to help develop good methods and procedures to farm sponges. For both species, survival of adult sponges was high in all seasons, while juvenile sponges had poor survival. Recruitment of L. brevis occurred in all seasons indicating that it is reproductively active throughout the year. P. croceus recruited mostly in autumn, this observation supports previous work that found the sponge to be reproductively active in summer and early autumn only. For both species, growth rates varied greatly between individuals and were unaffected by sponge size within the range examined. Sponges generally grew during winter and spring as the water temperature rose and shrank during summer and autumn as the water temperature fell. This growth pattern may relate to seasonal variation in food abundance, and for P. croceus it may result also from seasonal differences in reproductive investment. After 2 years, L. brevis and P. croce us had on average, halved and doubled in size, respectively. This indicates that wild sponges generally grow slowly and can also shrink in size. L. brevis showed a seasonal pattern of bioactivity, being most active in spring possibly to prevent the surface overgrowth of fouling organisms. P. croceus had no seasonal pattern of bioactivity, but individuals were either very active or inactive. These patterns of bioactivity may indicate an optimal defence strategy whereby sponges increase metabolite synthesis when they are most required. The bioactive metabolites in both species probably aid in competitive interactions and prevent predation and biofouling. The major environmental factors that are likely to influence the growth, survival and metabolite biosynthesis of farmed sponges and thus directly affect the success of a farming operation are season, exposure or water movement and depth. The effect of these environmental factors were examined in a series of short-term transplant experiments. Both survival and growth of L. brevis were greatest in winter when the water temperature was lowest, which probably reduces stress during transplanting. For P. croceus, survival was similar in winter, spring and autumn, while growth was greatest in spring probably because of greater food availability. Therefore, the response to the farming season can vary greatly between sponge species. During the summer transplant the toxic alga Gymnodinium brevisulcatum bloomed, killing most farmed explants. This highlights the danger to sponge aquaculture of adverse stochastic events that cannot be planned for or controlled. Growth of L. brevis and P. croceus generally increased as exposure increased thus showing clearly that although sponges are active suspension feeders, they rely greatly on the passive flow of water to provide food. The depth range (5-15m) examined in this study had no overall effect on the growth or survival of either L. brevis or P. croceus. Explants of both species farmed in similar environmental conditions varied greatly in growth. For both species, farming promoted greater synthesis of bioactive metabolites, which may indicate an optimal defence strategy. A reciprocal transplant experiment between northern and central New Zealand indicated that P. croceus could be transplanted great distances and survive. However, growth of relocated explants is reduced until they adjust to their new environment. A series of experiments was done to develop farming structures suitable for sponge aquaculture for metabolite production. Four general methods were examined: farming explants inside mesh structures, attached to substrate, with rope threaded through them and rope wrapped around them. Each was further divided into several specific methods examining the effects of various mesh sizes and rope materials. Most methods were found to be unsuitable because the farmed explants did not attach to the substrate but instead moved away from it and dislodged themselves. The two methods that showed the most potential for farming sponges, in terms of good growth, survival and metabolite biosynthesis, were threaded PVA rope and individual mesh bags with large holes and thin strand. These were developed into "rope" and "mesh" arrays. For nine months, L. brevis and P. croceus were farmed in rope and mesh arrays and harvested at different times. Harvesting involved the removal of new tissue growth leaving the explant "core" behind to regrow. The water temperature at the time of harvesting greatly affected the survival of L. brevis but not P. croceus. This supports the results of the short-term transplant experiments. Growth after harvesting was similar between harvested and non-harvested explants, indicating that healing of cut tissue and reorganisation of the canal system is not a drain on resources. This experiment showed that sponges can have very high growth rates. For example, explants of L. brevis and P. croceus in one treatment had grown by an average of 950% and 740% of their initial volume, respectively, in six months. Both rope and mesh arrays were found to be good farming structures, but differing patterns of growth and survival indicated that the two arrays are most suited for a particular type of sponge depending on its tissue structure. Rope arrays should be used to farm firm sponges such as P. croceus that can survive the threading process, while mesh arrays are best for farming soft, fleshy sponges like L. brevis that can grow quickly through the mesh strands. In some treatments, overall tissue yields were double the initial transplanted weight. As before, farmed sponges were generally more bioactive than wild sponges. An experiment to examine whether harvesting wild sponge populations is a suitable alternative method of supplying bioactive metabolites found that individuals of L. brevis and P. croceus could survive after removal of ≥90% of their biomass. Tissue regrowth was rapid and it was estimated to take between 1-4 years for individuals to grow back to their pre-harvested size. Although this suggests that harvesting wild populations of L. brevis and P. croceus can be an alternative method of metabolite supply, it is limited because of the relative scarcity of the sponges in the natural environment. This study examined the effect of different environments on the growth, survival and metabolite biosynthesis of sponges and developed methods and structures suitable for farming sponges. The high tissue yields from some treatments and the elevated bioactivity of farmed explants suggests that sponge aquaculture is a viable commercial method of supplying bioactive metabolites.

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