Increased domestic and international demand for aquatic foods have greatly enhanced aquaculture practices and production in Bangladesh, which is reflected in the national economy. However, the impacts of a fast growing aquaculture sector through the involvement of stakeholders, poorer sections throughout the value chain and broader rural livelihoods are largely underdeveloped and have frequently been ignored. The present study explores the impacts of dynamic aquaculture sector on stakeholders at production level and supply chain and test the hypothesis that aquaculture is enhancing rural livelihoods and benefiting the poor. Three aquaculture production systems in three areas of Bangladesh were selected for the study. These were prawn production in gher system in Jessore, pond fish culture in Mymensingh and rice-fish farming in Dinajpur. This selection allowed analysis both the impacts of domestic and export marketing of aquaculture products. Participatory research data collection tools; focus group discussions and participatory mapping were commonly used along with questionnaire surveys to ensure participation of stakeholders. Aquaculture, in general, found to have had significant impacts on rural livelihoods. The greatest effect of aquaculture on farming households were observed in income and consumption. Integrated aquaculture systems were the regular source of fish and vegetables and constitute more than half of the fish and vegetables consumed by farming households. While income from aquaculture was the highest among the several household income sources, the main cash crop differed between the systems studied. Prawn, fish and rice was the main cash earning crops for gher farming, fish farming and rice-fish farming respectively. Qualitative investigation suggested that aquaculture not only increased income through greater production volume, but also improved farmers’ assets through income diversification to farm and non-farm sources. The other important outcomes of aquaculture were the enhancement of social safety nets through increased sharing of inputs and labour among farmers. Commonly the aquaculture systems were found to be more intensive with an increasingly commercial attitude over the last ten years, which affected the intra-household labour distribution leading to a greater role for women in production management. While the three activities; fish feed preparation, feeding and growing vegetables performed by vast majority of women could be attributed to their inherent involvement with agriculture, hard physical work like harvesting ponds and pond construction were mostly carried out by the women from poor households as a strategy to reduce hired labour cost. The women’s’ increased involvement in aquaculture not only increased their overall workload, but also empowered them in household decision making to some extend. However, involvement in decision making was related to the level of involvement in production activities. The impacts of aquaculture spread beyond the farming households to the broader rural livelihoods. Wage labourers and fishers (harvesting teams) two of the poorest groups of people directly involved were benefited most over the last ten years. Intensification of aquaculture increased the demand for hired labour leading to a structural shift in the agricultural wage labour market in farming communities. About half of the agricultural labourers were found part-time employed in aquaculture activities in Jessore and Mymensingh. In Dinajpur intensification of rice cultivation had a much higher effect on the demand for labour than aquaculture. Increased employment in rural areas increased real labour wages by about one fifth over the last ten years and subsequently improved livelihood outcomes. Declining fish catch due to both decreased natural fish stocks and more restricted property rights, professional fishers benefited by diversifying their livelihoods into the aquaculture sector. While, many of the fishers permanently changed their profession to prawn marketing in Jessore, the rest were full-time or part-time employed in harvesting ponds and/or retailing fish in markets. Such diversification of income greatly reduced seasonal vulnerability and improved livelihood outcomes. The role of fish marketing, which is a critical institution in rural livelihoods, was found to facilitate the growth of the aquaculture sector. High demand of aquatic products and the diverse options of marketing fisheries enabled farmers to meet their initial requirements. More commercial operations of aquaculture increased farmers’ awareness and linkages to markets. However, typically the worse-off farmers were the slowest to capture new market opportunities, often due to their poor resources and human capital. Fish marketing was found to be run by the private sector and government provided the infrastructure facilities, except prawn processing plants, which were developed by private sector. While the fish market transactions were fairly efficient, markets facilities and infrastructure were commonly poor and need of government investment for improvement. A gradual growth of fish and markets in the rural areas was observed in the study; this was driven by the increased demand for fish through increased population and supply from aquaculture. The marketing intermediaries provided important services despite their small share of consumers’ price and ensured a fair share for farmers. The auctioneers provided a vital role in running the supply chain with investment and credits, which ensured fair competition in the pricing process. Marketing of aquatic products was not only a mechanism of product transaction, but also provided critical livelihoods for rural poor. On average about one hundred people, including retailers were involved in auction markets and eight people in prawn depots. Importantly the number of people in marketing was found to have increase over the years. Access for different groups of poor people to marketing jobs was found to be significant in rural livelihoods. The asset base and daily earning indicates that more than three quarters of the marketing intermediaries were poor; some of them were from poorest and low cast Hindu society. Greater flexibility of entry and exit to the jobs enabled the poorer sections to diversify their livelihoods, which enabled to cope with seasonal variability of opportunities and stable income. The marketing employment provided then increased livelihood welfare and social security. Finally, it can be concluded that the promotion of aquaculture not only increased much needed food availability but also generated critical livelihoods and marketing is not just a mechanism of product flow, but also providing livelihoods welfare to poorest sections of the society. The micro level findings of the study regarding impacts of aquaculture indicate that aquaculture production and marketing have significant impacts on enhancing rural livelihoods in Bangladesh.

Fish meals (FM) and fish oils (FO) are used extensively as the main protein and lipid sources respectively in industrially compounded salmon feeds, mainly due to their excellent nutritional properties. Nevertheless, several reasons dictate the utilisation of sustainable alternative protein and lipid sources and the subsequent reduction in the reliance on fishery-products in aquafeeds. Soy protein concentrate (SPC) is a very promising alternative to FM Hence, the main objective of the present thesis was to investigate the effects of the increased substitution of FM withSPC, lysine and methionine on the growth performance and immune responses of early and late stage Atlantic salmon parr prior to and after vaccination with commercial vaccines (Experiments II and V presented in Chapters 4 and 6). Furthermore the effects of increasing dietary levels of SPC with consistent and/or increasing dietary supplementation of phosphorus on the Atlantic salmon parr’ body proximate and mineral composition or the skeletal mineral composition respectively, prior and post-vaccination with commercial vaccines; under continuous light or under 12 hours light: 12 hours dark photoperiod (Experiments I and V presented in Chapters 3 and 5 respectively). Lastly the impact of FM-, FO- and fishery-free diets on the growth, carcass proximate composition and immune status of Atlantic salmon post-smolts was investigated (Experiment III presented in Chapter 7). In the latter experiment six diets were tested including: two commercially applied marine based diets, one with partial inclusion of vegetable proteins (VPs) and oils (VOs) according to the EU standards (2011-12) (MBE) and one with partial inclusion of VPs, VOs and land animal-by product (ABP) proteins according to the non-EU standards (MBABP); a fully vegetable protein (VP) diet; a fully algal and vegetable oil (VO) diet; a marine-free VP and VO and algal oil diet (VP/VO) diet; and a marine-free diet with a mix of VPs and land ABP proteins and lipid from VOs and algal oils (MFABP). The results of the Experiments I and II (Chapters 3 and 4) show that late Atlantic salmon parr can grow efficiently on SPC80 diets, however, they require longer periods to adapt to these diets compared to fish fed diets containing lower levels of SPC as a protein source. Decreased mineralisation of body cross-section was observed for salmon fed increasing dietary SPC. Vaccination improved mineralisation for the high dietary SPC salmon groups. However, continuous light exposure promoting fast growth appeared to be detrimental for Atlantic salmon body cross ash, Ca, Mg, Mn, P and Zn. Moreover, it was demonstrated that substitution of up to 50% of high quality FM protein with SPC and constantly added P has the minimum possible impact on late salmon parr growth, whereas it stimulates several immune parameters prior to immunisation. Immunostimulatory effects were also shown for the diets with higher dietary SPC levels. It is not clear if these results were an effect of increased FM replacement with SPC or not properly balanced levels of dietary P. The Experiments III and IV (Chapters 5 and 6) illustrated that early stage Atlantic salmon parr can accept diets with up to 58% protein from SPC without serious effects on body growth. However, higher levels can severely affect salmon growth performance. Moreover, it was shown that long-term feeding of salmon with increasing dietary SPC combined with increasing phosphate supplementation, alone or in combination with vaccination can actually be beneficial for Atlantic salmon parr bone mineralisation. However, mineralisation in vaccinated fish was higher than in PBS-injected fish. This could be linked to the slower growth of vaccinated salmon allowing their developing bones to mineralise properly. Changes in the modulation of the different components of the complement activity was revealed in Atlantic salmon fed increasing dietary levels of SPC. The modulation of complement activity was demonstrated at both studies utilising increasing dietary SPC concentrations, indicating that complement componenets are among the most prominent immunological markers upon dietary FM replacement with SPC. However, overall no differences in total complement activity and therefore the immune capacity and resistance against Aeromonas salmonicida were observed among the salmon groups receiving increasing levels of SPC. Lastly in Experiment V (Chapter 7) higher growth performance indices (weight gain, SGR and TGC) were evident in the MBE salmon compared to the MBABP group, salmon fed diets with complete eleimintion of FM or FO (VP and VO respectively) and fish fed two diets with total substitution of both marine derived feed ingredients, three months after the start of the feeding trial. Higher feed intake was demonstrated for both MBE and VP salmon compared to the other groups for the duration of the first period. The above results could have been influenced by discrepancies in the size of the fish at the start ofthe trial, revealing flaws in the experimental design. Both MBE and VP salmon groups also presented the highest feed conversion ratios, revealing the lowest efficiency in dietary nutrient utilisation in comparison to the rest of salmon which exhibited no differences in feed efficiency, revealing an overall better performance of the MBABP and diets with low levels of marine feedstuffs. Improved FI compared to the values of the first period and higher SGR and TGC values were demonstrated for salmon from the latter treatments compared to MBE and VP salmon, during the second part of the study, revealing compensatory growth for these groups. VP salmon demonstrated the highest and VO salmon the lowest condition factor values. The former finding might possibly be related with higher fat accumulation in the viscero-hepatic tissues. No differences were observed in carcass moisture, protein, fat and ash concentrations among the dietary groups of fish. Furthermore, no differences were demonstrated in terms of total and differential leucocyte counts, plasma haemolytic activity, plasma protein and total IgM levels, stimulated and non-stimulated HKM burst activity among the different dietary groups. However, lower haematocrit values were observed in the MB and VO-fed groups compared to the MFABP and VP/VO groups. Furthermore, decreased lysozyme activity was observed for all diets in contrast to the control groups, whereas FM-free diets promoted plasma anti-protease activity. The former result could have been an effect of either immune or stress induction, whereas the second is regarded as an immunostimulatory effect. The results suggest that marine-oil, marine-protein and marine-free diets could be satisfactorily used for Atlantic salmon post-smolts without severe reductions in their innate immune responses, although longer adaptation periods might be required for the fish to fully accept these diets.

The Atlantic salmon (Salmo salar) is an iconic species that dominates the global finfish production sector with increasing market demand. The Scottish industry and government alone aspires for expansion of the sector to 210,000 t by 2020 with 154, 000 t produced in 2013. As such, there are pressures to improve sustainable development in particular to minimise the genetic impact of escapees on wild populations and reduce sea lice infection which are required for the granting of “green licenses” in Norway. The use of triploidy has been tested in the 1980’s with little success owing to suboptimal rearing conditions leading to elevated mortalities, poorer growth and a higher prevalence of deformities, in particular of the skeleton. Collectively: recent success of triploid trout farming, expansion to the salmon production sector and potential resulting pressure on wild stocks through escapee increases have reinstated interest to implement artificially induced triploid Atlantic salmon in commercial production. As diploid Atlantic salmon have undertaken extensive domestication to achieve the high quality production and welfare standards observed to date, triploid conspecifics too require husbandry optimisation to realise potential. In particular, industrialisation requires that higher observations of deformities and inconsistent growth trajectories during seawater ongrowing be resolved through optimisation of rearing regimes and subsequent standardization of husbandry protocols. Triploids possess additional genomic material and increased cell size yet reduced frequency that reflects known differences in physiology and supports that, in effect, triploids should be considered as a new species relative to diploid conspecifics. Therefore, this doctoral thesis aimed to study nutrition and temperature effects on triploid Atlantic salmon traits throughout the production cycle from ‘egg to plate’. Nutrition trials aimed to improve growth potential and mitigate skeletal deformities both in freshwater (FW) and saltwater (SW) whilst attempts were made to define a window of smoltification to ensure optimal ongrowing performance. Finally, impacts of embryonic temperature regimes that are known to impact long term performance and deformity development in triploids, were examined in relation to DNA regulation and yolk composition in an attempt to underpin potential mechanisms for the environmental impact of temperature on developmental phenotype. One of the main restrictions to triploid Atlantic salmon implementation is the increased prevalence and severity of skeletal deformities, particularly after the maring phase. The work performed in this thesis first demonstrated that protein and/or phosphorous (P) supplementation throughout SW ongrowing not only reduced the level of severely deformed (≥ 10 deformed vertebrae observable by x-radiography) individuals by 30 % but also sustained 6.8 % faster growth and improved harvest grade compared to triploids fed a standard grower diet (chapter 2). Comparison of x-radiography and severely deformed individuals between harvest and sea transfer highlighted that protein and P supplementation arrested deformity development whereas prevalence increased in triploids fed a standard grower diet. This implied that severe deformities were of FW origin and strongly suggest requirement for improved nutrition in FW to optimise SW performance. Therefore investigation of higher dietary P inclusion in FW was investigated and results showed significantly reduced number of deformed vertebrae and no severely deformed individuals in those fed 19.7 g total P Kg-1 compared with those fed 13.0 & 16.7 g total P Kg-1 (chapter 3). Most deformities were localised in the central (vertebrae 27 – 31) and caudal (vertebrae 52 – 57) regions for all treatments. However, triploids fed lower dietary P displayed a particular increase in prevalence within the tail region (vertebrae 32- 47) which is consistent with SW ongrowing reports and results from chapter 2, further highlighting FW origin of higher vertebral deformities reported in SW ongrowing in triploids. Higher P supplementation in FW also significantly improved growth in triploid parr compared to diploids and lower supplementation. However, this effect did not transpire in later FW smolt stages where weights were significantly higher in triploids fed lower compared to higher P supplementation. Expression of target genes involved in osteogenesis and bone P homeostasis in vertebrates were then analysed and a ploidy effect of osteogenic genes alp, igf1r and opn as well as a dietary effect on P homeostasis gene fgf23 was apparent in the parr stages but not smolt. In addition, stronger ploidy-diet effects were also observed in parr stages for whole body mineral concentrations. Collectively, growth, gene expression and whole body mineral content results indicate these earlier parr life stages may be more sensitive to P supplementation. This pronounced effect may be a consequence of seasonal accelerated growth associated with this period, where higher temperatures were also observed. The potential for shorter P supplementation windows in commercial production was addressed in chapter 4 with hope to cut economic cost to raw mineral inclusion in feed and also mitigate potential anthropogenic eutrophication on the environment that may be induced by P leached through uneaten feed and faeces. Triploids were fed higher dietary P (17.4 g total P Kg-1) until either early (5 g) or later (20 g) parr stages, or smolt (83 g) and monitored for performance throughout freshwater (FW) development. During later parr development (30 g), x-radiography assessment demonstrated that increased dietary P reduced the number of deformities and severely deformed individuals with no indication that feeding P for shorter windows improved skeletal integrity. Hence, P supplementation may be required throughout FW development for optimal skeletal performance. In addition, no differences in deformities were observed between triploid treatments at smolt. An effect of dietary P supplementation on whole body mineral concentration was observed in the early and later parr stages that was not as pronounced as smolt, which is consistent with results in chapter 3. Together, these results indicate that skeletal assessment during early developmental stages may not reflect smolt performance most likely as a consequence of seasonal effects of improved linear growth in the cooler winter temperatures prior to smolt where reversible deformities observed at parr may also be alleviated. In the same study (chapter 4), the inclusion of the probiotic Pediococcus acidilactici (Bactocell™) was also tested as a means to enhance gut assimilation as suggested in previous studies and therefore reduce the levels of P supplementation. Results clearly indicate superior skeletal performance in parr (30 g) as well as significantly less deformed vertebrae and no severely deformed individuals. However, at smolt (~83g), no effects of the dietary probiotic treatment were observed which may also be attributed to seasonal effects. Overall, nutritional research clearly indicate triploids require higher dietary P for optimal growth and skeletal development, which although is not consistent between life stages, is ultimately required throughout FW for optimal skeletal development at smolt. The use of probiotics offer a promising avenue for reduced P requirement in FW feed and further research should verify results and assess long-term performance. Timing of SW transfer according to correct parr-smolt transformation (PST) is essential for survival and growth performance in ongrowing where feeding and growth rate accelerate post-transfer. So far, SW transfer regimes and in particular the smoltification ‘window’ remains loosely defined in triploid Atlantic salmon and it is crucial that this be addressed to ensure optimal ongrowing survival and performance.

Sur la période 2006-2008, les prix de la plupart des produits agricoles ont connu une hausse spectaculaire. Un des facteurs explicatifs de cette flambée des prix est le changement climatique. En effet, l’instabilité pluviométrique et les températures extrêmes affectent négativement les récoltes agricoles et entraînent une baisse de l’offre alimentaire sur les marchés internationaux qui contribue à la hausse des prix agricoles. La flambée des prix agricoles et le changement climatique soulèvent de sérieuses préoccupations en ce qui concerne l’inflation et le bien être des populations dans le monde et surtout dans les pays pauvres dépendants des marchés internationaux. Dans un premier chapitre, nous montrons à partir de modèles économétriques sur séries temporelles que la hausse du prix du pétrole et les fluctuations du dollar américain sont les principaux facteurs de la hausse des prix internationaux agricoles. Dans un deuxième chapitre, à l’aide d’un modèle de cointégration non linéaire, nous mettons en évidence le fait que les hausses du prix du riz sur le marché international se transmettent plus rapidement aux marchés intérieurs du Burkina Faso que les baisses. Dans un troisième chapitre, nous montrons que la hausse du prix international du riz a un effet négatif sur la pauvreté et les inégalités de revenu au Burkina Faso. Le quatrième chapitre met en évidence l’effet négatif et significatif de la variabilité climatique sur la sécurité alimentaire dans les pays en développement. Cet effet apparait plus élevé dans les pays africains. Il ressort de cette thèse que les pays en développement et plus particulièrement les pays africains sont fortement vulnérables aux chocs de prix alimentaires et au changement climatique. Cette vulnérabilité s’explique par le fait que ces pays dépendent des importations alimentaires et ont un secteur agricole sensible au climat. Des initiatives de protection sociale des populations pauvres sont nécessaires compte tenu de l’accès limité à la nourriture engendré par la flambée des prix alimentaires. Des investissements viables pour une croissance agricole soutenue sont aussi nécessaires. Il peut s’agir d’investissements pour l’amélioration des infrastructures rurales et des services agricoles ainsi que pour la recherche de nouvelles pratiques agricoles moins sensibles aux aléas climatiques. / Over the period 2006-2008, the prices of most of agricultural commodities considerably increased. One of the explanatory factors of this surge in prices is climate change. Indeed, rainfall instability and extreme temperatures negatively affect agricultural crops and lead to reduced food supply in international markets, which contributes to the rise in food prices. Soaring food prices and climate change raise serious concerns regarding inflation and welfare of households in the world and especially in poor countries that depend on food imports. In a first chapter, using econometric models applied to temporal series, we show that rising oil prices and fluctuations in the U.S. dollar are the main causes of the rise in world food prices. In a second chapter, using the threshold cointegration tests, we highlight the fact that the imported rice prices in the local markets of Burkina Faso respond more rapidly to increases than to decreases in the world price. In a third chapter, we show that the increase in the world rice price has a negative effect on poverty and income inequality in Burkina Faso. The effect is lower in the rice-producing areas but remains negative. The fourth chapter highlights the significant and negative effect of climate variability on food security in developing countries. The effect is higher in African countries than in other countries. The main message of this thesis is that developing countries and especially African countries are highly vulnerable to food price shocks and to climate change. This vulnerability might be explained by the fact that these countries depend on food imports and have an agricultural sector sensitive to climate variability. Initiatives for the social protection of poor households are required due to limited food access caused by soaring food prices. Investments for sustained agricultural growth are also required. These are for example investments for the improvement of rural infrastructure and agricultural services as well as development of new agricultural practices less sensitive to climate.

Mobility and Pathways to Autonomy of Women: A study of informal workers in fisheries sector in Kerala, India Mobility defined as the freedom and ability to move has intrinsic and instrumental values in promoting human development. Paid work which involves mobility associated with work can be a ‘capability-enhancing’ experience when such mobility improves opportunities and enhances freedoms. However, the existing studies have neither examined nor measured mobility with its multiple domains for women. My thesis fills this gap in research by exploring the multiple domains of gendered mobility by measuring mobility as a single construct and analysing whether mobility is a ‘capability’ for women workers which improves autonomy and agency. It is inter-disciplinary as it is situated at the confluence of development studies, human geography and sociological disciplines. The following features of the thesis make it unique in the development studies discipline. First, the contextual setting is unique as it is based in Kerala, which is a socially progressive state in India. The thesis unearths the underlying structural constraints in the Kerala model of social development for transformation of women workers under patriarchy. It is a comparative study which examines the household autonomy and agency of two types of informal women workers in the post-harvest fisheries, namely ‘peeling workers’ linked to production chains and ‘fish vendors’ who are self-employed. Second, the capability approach provides the theoretical framework for the analysis of mobility of women as capability and it introduces a new concept of ‘transformational mobility’. By examining mobility using the Rasch Rating Scale Model (RSM) for the first time in development studies, the thesis operationalises capability measurement by introducing the measurement scale of mobility of women workers which empirically delineates the multiple domains of mobility based on the constraints faced by women. Third, the mixed methods research design using survey data and qualitative interviews of women workers provide better insight and contextual understanding of women’s work. An innovative method, namely, the Crisp set Qualitative Comparative Analysis (CsQCA), explores the causal mechanisms that bring about ‘transformational mobility’ in women workers. The thesis empirically proves the significance of social and human capital factors like caste, low education of spouse and marital status along with the underlying patriarchal structures that determine pathways to transformational mobility and decision making of women. Lastly, the qualitative analysis using classic grounded theory contributes to the emergence of substantive theories for women workers which reflect contrasting agentic behaviour of peeling workers and fish vendors in the context of Kerala. The lack of collective agency among peeling workers questions the claims of Kerala model of development in improving the agency of women. The findings confirm that work mobility associated with informal low paid work is not necessarily a capability for women in fisheries.

Over the last 3 decades, freshwater aquaculture has become one of the most important food industries. However the constant introduction of a reduced number of very successful species for aquaculture has been identified as one of the main activities related to the alarming decline of fish biodiversity worldwide. This issue has raised awareness amongst the scientific community, governmental authorities and the general public towards freshwater fish biodiversity. This new awareness has promoted the development of “green” markets and environmentally friendly strategies, aiming for a reliable production of protein sources. The development of native species aquaculture has been presented as a strong alternative for sustainable aquaculture and the protection of biodiversity. However, it seems clear that unplanned native species aquaculture developments can be as detrimental on local biodiversity as the introduction of exotic fish, if not more dangerous. Therefore, the advantages and disadvantages of native species aquaculture have to be clearly analysed before any aquaculture development. This study aimed to establish a philosophical background regarding the use of native fish species in aquaculture in contrast to the introduction of exotic species that may compete for a similar niche as food in local markets. The main ecological impacts that exotic fish species may have on natives, such as competition, predation, and hybridization were discussed. In addition, a well planned native species Aquaculture Strategy for the Protection of Biodiversity was produced, at catchment level, within a Geographic Information System (GIS). For the development of the native species aquaculture strategy in central Mexico, four species of Atherinids (Chirostoma estor, C. Jordani, C. promelas and Atherinella balsana) and two species of native Ictalurids (Ictalurus balsanus and Ictalurus dugesii) were included in this study. These six species are relatively new to aquaculture and they were selected on the basis of their importance in local fisheries and markets in their native basins of the Lerma-Santiago and Balsas rivers. Both of these basins are of great importance in central Mexico, not only because of their biodiversity but also because of their high human population densities and socio-economic status. The use of Geographic Information Systems was a fundamental factor in the development of the native species aquaculture strategy at catchment level, consisting of site suitability models (SSM) for each species in their corresponding native catchments. Overall, SSM identified 13,916 km2 and 11,178 km2 highly suitable for aquaculture of the studied Atherinids and Ictalurids respectively, based on Water, Soil and Terrain, Infrastructure and Risk sub-models. A set of predictive species distribution models (PSDM), which related ecological characteristics for each studied species with relevant environmental and topographic parameters into a GIS, were also produced. Such models were developed for the establishment of potential natural ranges of distribution for each species, as well as their potential to become exotic in new environments, as a potential for invasion model (PI). Based on a partial verification, both PSDM and PI models produced results that were satisfactorily consistent with the known distribution of each modelled species. The combination of SSM and PSDM produced an Aquaculture Strategy for the Protection of Biodiversity model (ASPB) which identified the most environmentally friendly suitable areas for aquaculture sites. In contrast, the combination of the SSM with PI models into an ASPB model identified the site suitability potential for non-native species that are genetically close to native ones, in an attempt to reduce the known impacts that exotic species have on local biodiversity. In this way the ASPB model identified 7,651 km2 suitable for aquaculture of I. balsanus in its native Balsas basin and 15,633 km¬2 suitable for aquaculture of the non-native I. dugesii. ASPB models were produced for all the studied species. The final results were used to produce a set of guidelines for the development of sustainable aquaculture of native species at catchment level that cover genetic and ecological implications, as well as a well planned decision making tool produced in a GIS.

Ricefield based fish seed production (RBFSP) in irrigated spring (boro) ricefields after initial introductions by external promoters has spread among farmers in parts of Northwest Bangladesh. This approach to producing juvenile fish, rather than by specialised geographically clustered hatchery and nursery enterprises, has been recognised as a strategy for decentralised production that makes large high quality seed available locally and supports food fish production. RBFSP has been promoted by the international NGO CARE as part of a process to improve rice-based livelihoods of farming households using a farmer field school (FFS) approach in two consecutive projects between 1993 and 2005. The approach is technically simple and is based on the stocking of common carp (Cyprinus carpio) eggs and Nile tilapia (Oreochromis niloticus) broodfish in ricefields. As a new approach to farmer level fish seed production, its livelihood impacts on the farming households as well as associated actors; its adoption, adaptation and rejection process in farming households; and its cost-effectives for dissemination at farmer level were not well understood. This thesis mainly applies the concept of the sustainable livelihood approach (SLA) using tools and processes of the growing family of participatory research. A systems approach was used to ensure that the key stakeholders including households, community and extension organizations were included. The study was initiated with a well-being analysis of community households to identify poorer households before exploring impacts of RBFSP on poorer producing households (RF) compared to non-producing (NRF) households based on one-off and longitudinal surveys. Livelihoods impacts on other actors linked directly and indirectly with RBFSP were also investigated. The adoption process of RBFSP at the household level and the cost-effectiveness of its promotion were assessed. Impact studies at the household level showed that RF households were significantly larger and had lower levels of formal education than NRF. Adoption of RBFSP had improved practical skills and hence substantially improved human capital in RF households. RF households tended to have more of their ricefish plots located adjacent to their households. Poor and intermediate adopters had smaller riceplots than better-off households but higher seed production efficiencies (poor-315.1 kg fingerlings/ha; intermediate-419.1 kg fingerlings/ha) than better-off households (294.6 kg fingerlings/ha). In addition to direct consumption of large fingerlings, RF households restocked them for further growth in their household ponds in doing so increasing yields by 60%. Fish consumption increased substantially in RF households based on their own production reducing their dependency on purchase from markets. The year round longitudinal survey revealed that activities for RBFSP were compatible with their existing rice-based agriculture activities for household members including men, women and children. The relatively limited income from fingerling production improved cash flow in the low income months. Consumption of large size fingerlings from ricefields provided nutrient dense food in the ‘hungry gap’ months when supplies of wild fish were poor, smoothing consumption. Apart from RF households, RBFSP extended its livelihoods impacts to a wide range of actors in and around the seed producing community. Poor fry traders were found to be key actors in the spread and support of RBFSP. On average fry traders supplied fingerlings to 35 foodfish producers within a mean distance of 5 Km from producing households in a community where RBFSP was well established. The end users (foodfish producers) included households with their own ponds, ponds with multiple ownership and larger waterbodies leased by small groups. Locally available RFBSP juveniles were attractive to each of these groups, supplementing hatchery derived seed. A large number of complex socio-cultural and technical factors were related to household level adoption of RBFSP. The major factors included use of cash generated to prevent distress sales of rice; lack of requirement to use pesticide in ricefields; meeting the household consumption demand; capacity to restock fingerlings in ponds; lack of any negative effects on rice production; increased non-stocked fish production in riceplots; simplicity of the technology; ease of fish harvest from riceplots; increased ability to gift fingerlings/foodfish to relatives and neighbours; more efficient use of both riceplot and irrigation pumps. The most important reasons for households not attempting or quickly rejecting RBFSP were labour conflicts with other activities. However, lost access to the riceplots through changes in tenure was the most common cause of late rejection by households who had practiced RBFSP for several years after withdrawal of CARE support. Location of fish seed producing plots close to the homesteads facilitated household women to contribute to seed production activities through feeding and looking after fish. Women were able to decide and control resources generated from fingerling sales as well as choosing to gift fingerlings to their relatives. Informal transfer of fingerlings in this way stimulated spread of RBFSP. Decentralised fish seed production was promoted through FFS very cost effectively. The introduction of an improved strain of Nile tilapia (GIFT) broodfish greatly enhanced the returns from decentralised seed production based on common carp alone. High levels of secondary adoption improved benefits from promoting RBFSP. The major benefit derived from the improved returns to food fish farmers using locally produced seed. Higher levels of net present value (NPV) and benefit cost ratio (BCR) were achieved based on promotion of mixed-sex tilapia in RBFSP than mono-sex tilapia produced in a large scale central hatchery. Cost-effectiveness in terms of multiplier development impacts on ramification of secondary adopters and, income of fry traders and foodfish producers, RBFSP also showed better performance than a mono-sex tilapia hatchery.

The Atlantic cod (Gadus morhua L.) fishery is of great economic importance to the Faroese economy. There are two separately managed cod stocks around the Faroe Islands, the Faroe Plateau and the Faroe Bank cod. Both have experienced dramatic decreases in size and informed management decisions are vital for both stock viability and exploitation. The stocks are geographically isolated by an 800 m deep channel and water temperatures are on average 1 – 2 ºC higher on the Faroe Bank than on the Faroe Plateau. There are clear phenotypic differences between the stocks; in particular, the markedly higher growth rate for the Faroe Bank cod has caught public and scientific attention. There is continuing debate regarding the relative importance of genetics and environmental contributions to the contrasting phenotypes. Analyses of reproductive parameters (field data and experimental captive spawnings) as well as analyses of microsatellite and single nucleotide polymorphism (SNP) markers were undertaken to better resolve the issue. Field data as well as data from experimental captive spawnings provided evidence of reproductive differences between Faroe Plateau and Faroe Bank cod. Peak spawning occurred earlier on the Faroe Plateau than on the Faroe Bank and this difference in timing of spawning was maintained in captivity. In particular, differences in sizes of eggs (average diameters of 1.40 and 1.30 mm for Faroe Plateau and Faroe Bank cod eggs, respectively) and indirect evidence of greater volumes spawned by the Faroe Bank females suggested stock differences with respect to egg size – egg number trade-off. It was hypothesised that the strategy adopted by cod on the Faroe Bank, with a higher number of smaller eggs, evolved in response to a more hostile environment (bare seabed and higher exposure to predators) experienced by early life stages in this area. Experimental captive spawnings with Faroe Bank cod showed a large interfamily skew in survival rates of cod eggs and fry. Egg size was identified as a useful indicator of survival rates in the egg stage, but egg survival rates could not be used to predict viability in later developmental stages, thus highlighting the importance of employing some sort of genetic monitoring of cod fry to ensure sufficient family representation in the progeny. While no tank effect was evident concerning fry survival, a significant tank effect was identified concerning body sizes of fry. Microsatellite data were analysed using large sample sizes of Faroe Plateau and Faroe Bank cod with the Faroe Plateau divided into two locations, Faroe Plateau North-East and Faroe Plateau West (cod from each of the two were known to belong to separate spawning grounds). Two Norwegian coastal cod samples were included as outlier populations. While no genetic differentiation was detected between the two Faroe Plateau locations, these analyses revealed a detectable, albeit relatively modest, degree of genetic differentiation between cod from the Faroe Plateau and the Faroe Bank (FST = 0.0014 and 0.0018; DJost_EST = 0.0027 and 0.0048; P < 0.0001 and P < 0.001 for the Faroe Plateau North-East – Faroe Bank and the Faroe Plateau West – Faroe Bank comparisons). These values were several times smaller than those between Faroese and Norwegian coastal cod (pairwise FST and DJost_EST values in the range of 0.0061 – 0.0137 and 0.0158 – 0.0386, respectively). Despite recent reductions in census population sizes for Faroe Plateau and, particularly, Faroe Bank cod, genetic diversity estimates were comparable to the ones observed for Norwegian coastal cod and there was no evidence of significant genetic bottlenecks. Lastly, data for one of the markers (Gmo132) indicated genotype-dependent vertical distribution of cod (as investigated for Faroe Plateau North-East cod). Contrary to some previously published studies, analysis of SNPs of two candidate genes for adaptive divergence, the hemoglobin gene Hb-ß1 and the transferrin gene Tf1, failed to detect differentiation between samples of Faroe Plateau and Faroe Bank cod analysed in this thesis. Of 3533 novel SNPs simultaneously discovered and genotyped by restriction-site associated DNA (RAD) sequencing, 58 showed evidence of genetic differentiation between Faroe Plateau North-East and Faroe Bank cod (P < 0.05). No single locus was fixed for different alleles between Faroe Plateau and Faroe Bank cod. A set of eight informative SNPs (FST values between Faroe Plateau and Faroe Bank samples > 0.25; P < 0.0005) were selected for validation in larger samples, that included cod from both Faroe Plateau areas and the Faroe Bank as well as Norwegian coastal and White Sea cod. Six out of the eight loci amplified successfully with a PCR-based method and there was 100 % concordance between genotypes of individuals screened by both techniques. Due to ascertainment bias, the SNPs should only be applied with caution in a broader geographical context. Nonetheless, these SNPs did confirm the genetic substructure suggested for Faroese cod by microsatellite analyses. While no genetic differentiation was evident between the two Faroe Plateau locations, significant genetic differentiation was evident between Faroe Plateau and Faroe Bank cod at five of the SNPs (FST values in the range of 0.0383 – 0.1914). This panel of five SNPs could confidently be used to trace groups of Faroe Plateau and Faroe Bank cod to their population of origin. In conclusion, multiple lines of evidence demonstrate that Faroe Plateau and Faroe Bank cod are truly two genetically distinct populations. While the findings contribute to a broader understanding of the biology and the genetics of Faroe Plateau and Faroe Bank cod, the novel SNPs developed may provide a valuable resource for potential future demands of i.e. genetic stock identification methods.

The potential for aquaculture development to make up for an annual 400,000mt shortfall in domestic fish supply was investigated. This involved an overview of the sector to determine its trends and operations and identifying strengths and constraints, a financial viability assessment of the sector, based on mode and levels of operation of existing farms, an assessment of the market and trade for cultured fish with a focus on Oreochromis niloticus, and finally, a GIS approach to update and reassess the potential for aquaculture development in Ghana. Data were obtained from both primary and secondary sources, the former, via fish farmer, dealers and consumer questionnaire surveys. Results of the study showed that interests in fish farming continue to grow with an overall annual average growth rate of 16% since 2000. The existing farms, 1300 in number were however very small with a mean farm size of 0.36ha and a median 0.06ha of which commercial farms accounted for less than 3%. Based on sizes, mode of operation and levels of input and output, five subsistence farm types were identified. Mean production from these pond-based farms ranged from 1436kg/ha/yr- to 4,423kg/ha/yr while that of a medium sized intensive commercial pond farm was 45,999kg/ha/yr. Commercial farming accounted for about 75% of 2006 aquaculture production. The main strength identified was the growing interest in both commercial and non-commercial fish farming and the main constraints were lack of quality seed, low levels of technical support and of knowledge in fish farming practices among non-commercial farmers. Net profits of commercial farms ranged from GH¢ 3,341 (US$3480)/ha/yr to GH¢ 51,444 (US$ 53,587)/ha/yr with payback from 1 to 4yrs, IRR at 35% to 105% and NPV from GH¢ 5,898 to GH¢ 236,412. By contrast, only two of the five non-commercial farm types made positive net returns ranging, from GH¢158 to GH¢1100/ha/yr, with minimum payback period of 14yrs, NPVs of less than 1 and the best IRR being just 4%, when initial capital requirements are full costed. Uncosted family labour inputs and negligible land opportunity costs improved viabilities for two farm types, where net returns/ha/yr increased by more than 50%, minimum payback dropped to 2 years, NPV from GH¢ 4839 to GH¢ 9330 and minimum IRR of 45%. Main constraints identified as affecting the profitability of subsistence farming were the relatively low prices of fish and the low levels of output which could be improved through better farming practices. From the market survey, a huge market potential for tilapia was identified with a current supply deficit of 41,000mt. The most preferred sizes by consumers and with potentially good market price for traders were those weighing at least 200g. For dealers, trading in cultured fish was found to be more profitable than trading wild capture tilapia because of lower wholesaler prices, gross profit margins were GH¢ 0.49/kg and GH¢ 0.25/kg respectively. Preference for tilapia was influenced by taste, availability, and its perceived health benefit. A key constraint to the sector was poor post-harvest handling and preservation of the fish resulting in shorter shelf life. From the GIS study, 2% (3,692 km2) of available land area was identified as very suitable for subsistence and about 0.2% (313.8km2) for commercial farming. A further 97.4% and 84.0% were identified as suitable for subsistence and commercial farming respectively. Areas with potential for cage culture were also identified, which were largely in the southern and mid-sections of the country. The overall conclusions are that based on natural resource requirements, market potential and financial viability, Ghana has the potential to totally make up the shortfall in domestic fish supply through aquaculture production. The current 400,000mt shortfall in domestic fish production can be achieved by 2020 by increasing overall aquaculture production by 60% per annum.

Over the past two decades, environmental history as an approach to the understanding and explanation of historical processes has become gradually fashionable amongst academics; empirical data collected over the North Atlantic proposed new trends with regards to economic patterns during the Viking Age. The increasing number of Viking Age sites exposed in Iceland, the amount of zooarchaeological collections highlighting an abundant presence of fish bones in the overall archaeofauna, together with one’s expertise in environmental history as well as a strong interest in socio-economic development during the Viking Age and medieval periods were many factors which help identify strengths and weaknesses with regards to the understanding of the emergence of commercial fish trade in Iceland, and to a lesser extent, the Faeroe Islands. The thesis proposes a new theory with regards to human adaptation to new environments, and subsequent economic developments based on the commercial exploitation of fish. The interdisciplinary aspect of this project using cultural sediment analysis and zooarchaeology, as well as concepts from anthropology and economic anthropology, allows for the theory to be tested by empirical data.