STORRE Collection: Electronic theses of Aquaculture Students.
http://hdl.handle.net/1893/13
Electronic theses of Aquaculture Students.2024-03-18T08:54:44ZSafeguarding the welfare of Scottish farmed Atlantic salmon: current practices and future prospects
http://hdl.handle.net/1893/35812
Title: Safeguarding the welfare of Scottish farmed Atlantic salmon: current practices and future prospects
Author(s): Wiese, Timothy
Abstract: Farmed fish welfare has become a growing priority as aquaculture continues to expand to meet global demand. The Scottish salmon farming industry is a prime example of this growth, reaching record highs in production and intensification over recent years. The compelling evidence for fish sentience highlights the ethical imperative of safeguarding the welfare of the millions of animals involved. Achieving appropriate levels of salmon welfare, however, presents considerable challenges. Animal welfare is a complex, multi-faceted concept, the intricacy of which is only further amplified when dealing with the anadromous life cycle of Atlantic salmon. The aim of this PhD was to provide industry-relevant contributions towards the monitoring and safeguarding of farmed salmon welfare. An additional aim was to validate or further refine a novel on-farm welfare assessment tool that provides the most benefits in this manner. Chapter 1 provides the context for this study, outlining key concepts of animal welfare, the importance of farmed salmon welfare, and various factors, indicators, and considerations that are important for farmed salmon welfare. Chapter 2 addresses the complexity of enhancing farmed salmon welfare by conducting a survey on the Scottish salmon farming sector, consulting industry professionals to better understand their current welfare concerns and research priorities. Chapter 3 investigates what role welfare standards can play in providing assurances for farmed salmon welfare, as well as how welfare practices within the industry have changed over the years, through examining changes in farm site compliance to these standards. Chapter 4 assessed the effectiveness of Qualitative Behavioural Assessment (QBA) in capturing changes in the behavioural expressions of Atlantic salmon following exposure to a stressful event. Chapter 5 summarises the findings from these studies, outlining how Chapters 2 and 3 informed the development of the QBA experiment conducted in Chapter 4 and the significance of QBA’s validation. Chapter 5 then develops on these findings, proposing a direction for future research regarding the potential for behavioural welfare assessment tools to utilise computer vision and machine learning technologies. The results from this thesis highlight the potential that non-intrusive, remote, animal-based welfare indicators have in improving the monitoring and management of farmed salmon welfare. In particular, QBA shows great potential as a unique welfare indicator within aquaculture. This is the first study to demonstrate QBA’s sensitivity to changes in the behavioural expressions of Atlantic salmon and highlight the unique insights it offers into salmon welfare.2023-07-01T00:00:00ZAssessing the environmental impacts and nutritional outcomes of Tilapia farming in Bangladesh
http://hdl.handle.net/1893/35811
Title: Assessing the environmental impacts and nutritional outcomes of Tilapia farming in Bangladesh
Author(s): Horn, Stephanie
Abstract: There is an urgent need to transform global food systems into sustainable models which provide affordable, healthy, and micronutrient rich foods for all. This requires data-driven interventions and policies guided by rigorous food system performance assessments. Life Cycle Assessment (LCA) modelling is increasingly being used to evaluate the combined environmental and nutritional performance of food systems, known as nutritional Life Cycle Assessments (n-LCA). This thesis utilises novel n-LCA methodology to assess tilapia aquaculture and integrated agriculture-aquaculture systems in Bangladesh.
The environmental and nutritional performance of fishponds, rice-fish co-culture, and poultry-fish co-culture was assessed by combining a nutrition metric, the Potential Nutrient Adequacy (PNA) metric, with LCA methods. Affordability assessments and food and nutrition security assessments were also performed to evaluate the economic and nutritional performance of the farming systems. Additionally, on-station experimental trials compared the environmental footprint and nutritional quality of four different tilapia strains cultured under intensive and semi-intensive feeding and harvesting regimes. A nutritional composition analysis was performed for tilapia taken from different farming systems across Bangladesh with results showing small tilapia, typically consumed whole, and large tilapia, from which only the flesh is eaten, have different nutrient contents due to the differences in consumption practices. Furthermore, diet, seasonality, and farm type significantly impact the level of nutrients in both small and large tilapias.
Fishponds were found to have an overall better environmental performance compared to the rice-fish and poultry-fish farms. Results show feeds, fertilisers, energy, and chemical inputs have higher environmental impacts compared to other material inputs across all farm types. Result from the affordability assessment identified tilapia and two other fish species (Cirrhinus mrigala and Esomus danricus) as the most affordable sources of essential micronutrients and has shown these three fish species have a better environmental footprint compared to the other 17 fish species found in the farming systems and considered in this study.
Results from the experimental trial, found the local strain had better productivity compared to the three genetically improved strains, and the intensively managed treatments performed better compared to the semi-intensive treatments in terms of nutritional quality and economic returns. When the nutrition metric was integrated into the LCA, results showed intensive treatments also performed better than semi-intensive treatments for several environmental impact categories.
In conclusion, this thesis provides an important example of how nutrition can be combined with Life Cycle Assessments and offers insight into the impacts nutrition metrics can have on the overall results of performance assessments. Utilising the potential nutrient adequacy metric as a nutritional functional unit provides a more transparent approach to food system LCAs, although further development, testing, and validation of n-LCA methodology is needed to refine the process. This thesis also shows the nutritional quality of tilapia has been undervalued in the literature and that tilapia can provide sustainable, affordable nutrition to populations across Bangladesh.2023-06-01T00:00:00ZEstimating the dispersal capacity of Scottish blue mussel (Mytilus edulis): From hydrodynamic modelling to genetic population structures
http://hdl.handle.net/1893/35695
Title: Estimating the dispersal capacity of Scottish blue mussel (Mytilus edulis): From hydrodynamic modelling to genetic population structures
Author(s): Corrochano - Fraile, Ana
Abstract: The blue mussel (Mytilus edulis) and the Mediterranean mussel (Mytilus galloprovin-
cialis) are the primary bivalve species in Europe, with France and Spain being the top
producers. In recent years, Scotland has also seen a significant increase in mussel pro-
duction due to a higher settlement of mussel larvae onto suitable surfaces, which is
crucial for cultivation. However, despite the growth of natural spatfall, limited re-
search on mussel farming methods in dynamic areas has led to inefficiencies and fluc-
tuations in production. As a result, there is a pressing need for improved management
practices to ensure sustainable growth in the industry.
This study seeks to address knowledge gaps concerning mussel dispersion, crucial for
effective mussel farming management, by investigating population genetics and em-
ploying hydrodynamic modelling. Presented is a comprehensive genome assembly
of the blue mussel, M. edulis, identifying multiple whole genome duplication events.
This assembly facilitates the development of precise genetic markers, contributing to
an improved understanding of the intricate genetic structure of Scottish mussel popu-
lations. Additionally, the study utilises a biophysical model to illustrate the high con-
nectivity of M. edulis populations, influenced by the rapid water currents and wind
direction on Scotland’s dynamic West Coast. This interdisciplinary approach inte-
grates population genomics and biophysical modeling, providing valuable insights
into various mussel farming areas across Scotland.
The findings suggest that understanding the connectivity of mussel populations and
the gene flow is essential for effective management practices. The population study
shows a mussel gene flow between key areas, leading to a rapid change in local pop-
ulations, exemplified by the noticeable alteration of genotypes from one generation
to the next. The ocean currents help mussels move around and spread their genes,
which creates a complicated network of mussel populations. By understanding this
connectivity, mussel farmers can make informed decisions on stocking and harvesting
strategies to ensure the sustainability of mussel farming practices in the long term.2023-05-04T00:00:00ZNutrition-sensitive solutions for aquaculture development in Africa
http://hdl.handle.net/1893/35684
Title: Nutrition-sensitive solutions for aquaculture development in Africa
Author(s): Kaminski, Alexander M
Abstract: Commercial aquaculture in Africa has boomed in recent years. The capital-intensive growth of tilapia aquaculture in countries like Zambia and Kenya is supplying thousands of tonnes of fish to markets. This has caught the attention of governments, donors and experts who have renewed calls for greater efforts to develop aquaculture in the region. Much of the focus is on defining and measuring production systems and pushing for improvements in production efficiency. While such approaches are important, an overfocus on production and productivity threatens to overshadow approaches that may be more beneficial for human nutrition and health outcomes. A fixation on commercial growth can disaffect smallholders and lower-income consumers who struggle to access the value chain efficiently. This thesis argues for a refocus of the current productivist paradigm towards more nutrition-sensitive aquaculture. It begins with a quantitative assessment of smallholder tilapia farmers in Zambia, teasing out the role of aquaculture to household livelihoods, dietary diversity, and food security; going beyond production potential by assessing the value of fishponds to farming systems and human wellbeing. This is followed by a chapter that introduces a nutrition-sensitive pond polyculture technology trialled in the same rural communities. The results show that cultivating multiple species and promoting intermittent harvesting of various micronutrient-rich fish increases nutrition security for households. The second part of the thesis assesses the oft-overlooked consumer preferences for tilapia compared to other animal-source foods, and why they are important to incorporate into value chain developments. A quantitative consumer study set in Kenya shows how a preference for small tilapia, especially among poorer people, can allow producers to redesign their production systems and target markets. A follow up chapter introduces a nutrition-sensitive solution for commercially-oriented production systems in Kenya, based on the results of a trial that purposively grew small tilapia by increasing stocking densities and shortening production cycles. The thesis concludes with an argument for inclusive value chains and greater food sovereignty where the needs of poor and vulnerable communities are included, and where nutrition and health outcomes are prioritised.2023-03-31T00:00:00Z