Browsing Master's theses in international fisheries management by Author
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- Browsing Master's theses in international fisheries management by Author
Browsing Master's theses in international fisheries management by Author
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Agbenya, Lilian (Master thesis; Mastergradsoppgave, 22-May-2009)[+][-]
Abstract: Abstract Child labour trafficking in the Lake Volta fishery of Ghana is one of the prominent issues receiving immense attention from various organizations, NGOs, Civil society within and outside Ghana and the government of Ghana. This is due to the adverse impact on the children’s developments. This thesis sought to find out the major causes of this phenomenon, tasks performed by these victims, the recruitment processes involved in this human trade and the condition under which these children work. It further seeks to investigate the measures and interventions put in place to curb this unabated problem. An exploratory study approach was adopted which led to the selection of Ogetse, one of the receiving communities along the Lake Volta in the Krachi West district of the Volta region. The data was collected using different data collection strategies and was analyzed qualitatively. Various theories of poverty were used in this study to explain the findings. The findings of this study reveal that poverty plays a major role in fuelling this problem however, other complex factors such as cultural norms, migration and institutional failures also contributes enormously to the problem. The children who are mostly boys between the ages of six and seventeen years performed tasks, such as fishing, mending of nets, diving and household chores. These children are made to work under extreme harsh conditions, waking up very early in the mornings at 3am or 4am and going to bed late in the evenings (11pm, 12am) mostly throughout the week without going to school and having little to eat and sometimes being flogged by their masters at the little offence. It also indicates that parents, family members, the fishers and agents are involved in this human trade. In addition the study also revealed that some effort is being made by government, NGOs, Civil Organizations and other institutions to combat this problem. Abstract Child labour trafficking in the Lake Volta fishery of Ghana is one of the prominent issues receiving immense attention from various organizations, NGOs, Civil society within and outside Ghana and the government of Ghana. This is due to the adverse impact on the children’s developments. This thesis sought to find out the major causes of this phenomenon, tasks performed by these victims, the recruitment processes involved in this human trade and the condition under which these children work. It further seeks to investigate the measures and interventions put in place to curb this unabated problem. An exploratory study approach was adopted which led to the selection of Ogetse, one of the receiving communities along the Lake Volta in the Krachi West district of the Volta region. The data was collected using different data collection strategies and was analyzed qualitatively. Various theories of poverty were used in this study to explain the findings. The findings of this study reveal that poverty plays a major role in fuelling this problem however, other complex factors such as cultural norms, migration and institutional failures also contributes enormously to the problem. The children who are mostly boys between the ages of six and seventeen years performed tasks, such as fishing, mending of nets, diving and household chores. These children are made to work under extreme harsh conditions, waking up very early in the mornings at 3am or 4am and going to bed late in the evenings (11pm, 12am) mostly throughout the week without going to school and having little to eat and sometimes being flogged by their masters at the little offence. It also indicates that parents, family members, the fishers and agents are involved in this human trade. In addition the study also revealed that some effort is being made by government, NGOs, Civil Organizations and other institutions to combat this problem. URI: http://hdl.handle.net/10037/1866 File(s) in this item: 1
thesis.pdf (2.470Mb) -
Agulló Núñez, Lara (Master thesis; Mastergradsoppgave, 06-Jun-2012)[+][-]
Abstract: Greenland halibut (Reinhardtius hippoglossoides, Walbaum) is a commercially important fish species in the Barents Sea. This fishery has been strongly regulated, including a fishing ban from 1992 to 2009. Studies of fish reproduction are needed to extend the knowledge about this species in order to improve management and to avoid another decay of the stock. This Master Thesis describes the relationships between fecundity (thousands oocytes per female) and length (cm) ("Fecundity=2 ×" 〖"10" 〗^"-6" " × " 〖"Length" 〗^"3.9418" ) and fecundity (thousands oocytes per female) and weight (g) (Fecundity=0.003 × Weigth^1.1251) for Northeast Arctic Greenland halibut based on 138 females taken in November-December 2011 on the continental slope of the Barents Sea. Fecundity was compared to previous data from the same area and it was found to be in the same range as data from 1996, 1997 and 1998. Maturity stages were stated using the new scale proposed by Kennedy et al. (2011) based on oocyte diameter measurements. These data were compared with the maturity stages given at sea, using both a standard macroscopic scale and the macroscopic scale special for Greenland halibut. Differences were found, both with regard to stating of maturity stages and the boundary between mature and immature individuals. Spawning stock size and total egg production were calculated using both methods, and an overestimation of the spawning stock size, as well as of the total egg production, was found when the macroscopic scale was used. Due to the fact that it is difficult to implement the microscopic scale at sea, it is proposed that when using the special macroscopic scale for Greenland halibut females, the boundary of immature females is moved from stage 1 to also include stage 2. URI: http://hdl.handle.net/10037/4355 File(s) in this item: 1
thesis.pdf (1.388Mb) -
Ali, Abdurhman Kelil (Master thesis; Mastergradsoppgave, 03-Jun-2002)[+][-]
Abstract: A resource management system combines a set of regulatory scheme within a particular resource to achieve a management outcome. The effectiveness of these regulatory measures depends on the support gained from the resource user group and the way they themselves define their problem, their involvement in the decisionmaking process, in installing and enforcing the regulations. Through semi-structured interviews, this study investigated what resource users think about: the status of stocks and the reason for any change, fisheries management issues and measures and management in partnership on Lake Zeway fisheries. It is found out that sample respondents understand and agree the resource is in undesirable state mainly due to increasing number of fishers and/or gears beyond the capacity of the lake, use of small mesh size/fishing for juveniles and on the breeding grounds. They expect a continued pattern of decline unless some possible measures undertaken to curb the problem. Respondents are, for most part, supportive of management. Most of them understand the importance of the variables that management can manipulate and agree on some fundamental element of a common management strategy but lack incentive for compliance due to the absence of property right. Moreover, they showed motivation and willingness to share management responsibility with fisheries officials. Consolidation of the community coupled with local control of resource base access and active involvement in the management thereof, are important ingredients for achieving true success – i.e. long term sustainability – in the exploitation of the fishery resources. URI: http://hdl.handle.net/10037/304 File(s) in this item: 1
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Alves, Dário Mendes (Master thesis; Mastergradsoppgave, 05-Jun-2003)[+][-]
Abstract: Analysis of video recordings performed by the submersible “Nautile” in the Bay of Biscay, NE Atlantic indicated that demersal fish species are associated to different types of deep-sea habitats. Four different dive transects were analysed with respect to environmental characteristics. A total of 19 fish groups were ordinated by means of canonical correspondence analysis, and the investigation was performed at the individual fish level. Microhabitat fauna was dominated by a diversity of suspension feeders indicating different gradients of bottom hydrology, particularly vertical and horizontal current flow. Physical, geological and biological factors revealed different strategies of habitat selection in fish. The most represented species, the orange roughy (Hoplostethus atlanticus) showed a clear association with complex bottoms, including coral reefs. Others, such as Coryphaenoides rupestris and Synaphobranchus kaupi, showed higher flexibility of adjustment to changing environments. These traits can be utilised in the study of the environmental impact of deep-sea fishing. Based on the same dives, the locomotory behaviour of 13 fish species was studied with basis on a qualitative analysis of selected individuals. The main swimming modes used in shallow waters were also detected in the demersal environment. Clear differences in locomotory behaviour were found among fish species, reflecting both convergence and diversity of strategies of utilization of the demersal niche space. URI: http://hdl.handle.net/10037/321 File(s) in this item: 1
thesis.pdf (4.325Mb) -
Amoako, Mary (Master thesis; Mastergradsoppgave, 08-Jun-2006)[+][-]
Abstract: A survey was carried out to investigate the prevalence and mean intensities of ectoparasites infestation on the gills and skin mucus of Nile tilapia (Oreochromis niloticus) in some selected fish farms in the Ashanti region of Ghana. Pond water quality was also determined. Oral on-farm interviews on pond management practices were carried out on the farms. The results obtained revealed three types of ectoparasites namely; Trichodina sp., monogeneans and Tetrahymena sp. of which the first two were prevalent on most farms. Tetrahymena sp. was found on one farm. The physico-chemical parameters and management practices were very similar in all farms. There were no strong relationships between ectoparasite prevalence and intensity and the physico-chemical properties and the management practices on the farms. the ectoparasites occurrences in infected farms might have been due to a chance effect. The general low prevalence and intensities of ectoparasites recorded in the infected farms is an indication that the Nile tilapia has a biotic mechanism which might have enabled it to reduce the growth rate of ectoparasite intra-population. The ectoparasites do not seem to pose a threat for the aquaculture industry in the Ashanti region as observed in this study, but measures have to be taken to secure the industry from unforeseen incidents, for instance in the introduction of non-endemic parasite species in the future. URI: http://hdl.handle.net/10037/297 File(s) in this item: 1
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Andrade Rodriguez, Hector Antonio (Master thesis; Mastergradsoppgave, 05-Jun-2003)[+][-]
Abstract: The rose-spotted snapper, Lutjanus guttatus, seems to be sequentially exploited by the shrimp trawler and the artisanal fleet along the Pacific Coast of Guatemala. The growth parameters of the snapper were estimated in the present study with basis on material collected in two fishing harbours. Other biological and fishery information was compiled to simulate stock dynamics with a yield-per-recruit model. This single-species model allowed the evaluation of possible outcomes of fleet interactions, in terms of relative yield, spawning stock development and profit. A large emphasis was put in the evaluation of skeletal structures, otoliths and vertebrae, to determine age. Vertebrae seem to be the best structure for ageing, as they revealed better ring definition, and resulted in more adequate growth patterns and plausible Von Bertalanffy growth parameters. The VBGF (total length-at-age) obtained with vertebrae was Lt = 66.4(1-exp(-0.13(t-0.03))). The age of first-capture (Tc) for the trawl and the artisanal fleets were estimated to be about 1 and 3 years, respectively. The age-dependent mortality was suggested to follow unimodal curves for the two fleets, owing to the patterns of selectivity of the gear and availability of the fish. The yield-per-recruit scenarios showed that for the suggested biological and fishery parameters, the highest yield of snapper is not being attained. Further, the model suggests that with the present fishing pattern high rates of fishing mortality could deplete the spawning stock. Implementation of size-selective practices that minimise the trawlers’ by-catch of L. guttatus, and an increase of the artisanal Tc (to above the maturation age, Tm, about 4.5 years) are likely to result in increased yield, total profit, and prevent recruitment overfishing. URI: http://hdl.handle.net/10037/299 File(s) in this item: 1
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Ardiansyah, Hasyim (Master thesis; Mastergradsoppgave, 30-May-2007)[+][-]
Abstract: The tsunami disaster in NAD province has affected and reduced significantly the social and ecological resilience of coastal communities. The ‘huge aid’ and large number of parties involved during fisheries rebuilding process are essential in supporting the rehabilitation of fisheries infrastructure and knowledge transfer in order to improve fishers and fish-farmers capacity in dealing with ecological feedback. This process is potential to present either the effective or the ineffective responses. The effectiveness is essential since the tsunami is seen as an opportunity for building resilient within coastal communities and better future of fisheries governance. However, tsunami occurred in the context of vulnerability and its impacts have caused the vulnerability, since the fisheries production assets wiped out by tsunami. The effective response is influenced by the ability of the disaster authorities and other parties involved providing a properly action and mechanisms that represents in the implemented policies. This ability also influenced by the previous experiences in designing the policy, as a mean to deal with social and ecological problems in the past. The response to this disaster has indicated to have potential to create vulnerability within survivors as well, which lower the ability to adapt to and cope with disasters. These, in the long-term goals, may promote less incentive to the resilient communities and preserve the status quo. The effectiveness can be achieved by understanding the diversity and coping strategies in the fisheries capture and aquaculture that mainly characterized by the livelihood strategies. On the other hand, understanding and strengthening the social capital of the individuals, households, fisher groups, and local institutions are essential, which enable to provide effective responses and adaptive capacity. These can be addressed through allowing the social learning framework to take place during rebuilding fisheries process. These frameworks also enable to provide feedback for the governance structure as an evaluation to ineffective response and as a tool to deal with the complexity of integrated intervention, including resource management after the tsunami. Keywords: Tsunami, rebuilding fisheries, vulnerability, social capital, effective intervention, learning framework, resilience. URI: http://hdl.handle.net/10037/995 File(s) in this item: 1
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Bampoe, Audrey Anima (Master thesis; Mastergradsoppgave, 15-May-2011)[+][-]
Abstract: The management of multi-species fisheries is usually challenging because of the high number of fleets and gears targeting numerous species. In recent times, the concept of metiers has been used to enable further understanding of spatio-temporal variation of species and behaviour of fishers. In the present study, an output-based approach (i.e. the use of landing data) was used to identify potential metiers in the artisanal fisheries of the Central region of Ghana. The landing data was over a five-year period – 2004-2008 and based on species caught by five main gears, namely Ali-Poli-Watsa (a type of purse seine net), beach seine, drift gill net, hook and line and set net gears. Multivariate analyses, namely Canonical Correspondence Analysis, Redundancy Analysis (RDA) and Generalized Additive Models (GAM) – were used to analyze catch per unit effort (CPUE) and revenue per unit effort (RPUE) on yearly and monthly basis respectively. The environmental variables used in the multivariate analyses were gear, year, month and temperature. It was observed that changes in catch and revenue rates followed seasonal patterns, with some gears recording their maximum revenue rates in the second semester of the year. Initially, three major gear groups were identified. Subsequent analyses led to the generation of two models – prey-gear niche and niche timeline – to further explain the interactions of the various gears across months and the implications of these to fisheries management was discussed. The results from the multivariate analyses were supplemented with data obtained from interviews of fishers in Winneba fishing community. It was observed that even though fishers had high fidelity to particular gears during fishing seasons, they sometimes diversified their target species. Lack of an alternative occupation to fishers threaten their livelihoods, thus it was recommended that fisheries managers or scientists explore ways of enhancing the resilience of fishers. URI: http://hdl.handle.net/10037/3527 File(s) in this item: 1
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Bantikova, V. Elena (Master thesis; Mastergradsoppgave, 14-Jun-2002)[+][-]
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Belandria Ojeda, Alexa (Master thesis; Mastergradsoppgave, 25-May-2007)[+][-]
Abstract: When conducting social research in the four communities located in North-East Venezuela, it was understood through the course of communication that there was a very important issue affecting, in one way or another, the development of the sardine fishery: Governance. New formal fisheries institutions have been established since 1999 related with the election of the president Hugo Chavez in 1998. When studying governance it is the belief of the researcher that political principles and values give structure to the system. On that account, the question of how the existing fisheries governance has been formed as a result of the socio-political reforms taking place in Venezuela since 1998 becomes central. The State remains as the principal actor and controller of the interactions. Therefore, special attention is paid to the interactions between the State and the civil society, including the market. The organization of cooperatives and the supply of financial resources for fish extraction represent the base of the State’s programs. The future of governance in Venezuela is unclear, but signs that Venezuela might be moving towards “cooperativism” with high participation of the State exist. Nevertheless, the system can have its pitfalls. For that reason, the construction of partnerships between the State and cooperatives is a strategic alliance that might be successful if the relation is based on trust, equality, and mutual understanding and obligations. URI: http://hdl.handle.net/10037/999 File(s) in this item: 1
thesis.pdf (1.515Mb) -
Berachi, Isaac Ghebregziabher (Master thesis; Mastergradsoppgave, 28-May-2003)[+][-]
Abstract: Artisanal marine fisheries of Tanzania involve the majority of the coastal population whose survival is entirely dependent on the coastal fishery resources. In this paper the artisanal sector of the marine fisheries for the period 1987 -2000 is analysed by applying Gordon-Schaefer Surplus Production Model on time series of total catch and standardised effort. Static reference points such as open access equilibrium, maximum economic yield and maximum sustainable yield are established in addition to the more dynamic optimal yield solution. The results show that the fishery has expanded beyond the economically optimum point where the current level of effort is further beyond that of maximum sustainable yield resulting in suboptimal yield, i.e. it has been evident that there is already overfishing in the inshore waters where majority of artisan fishermen concentrate. The major constraint is assumed to be the inadequate institution and legal framework for fisheries management. Also social and equity considerations have been the bottlenecks for the implementation of regulatory measures which would cause further unemployment. Thus, the present study calls for policy intervention to rescue the stock from the existing high fishing pressure that would lead to depletion. URI: http://hdl.handle.net/10037/303 File(s) in this item: 1
thesis.pdf (159.7Kb) -
Borit, Melania (Master thesis; Mastergradsoppgave, 15-May-2009)[+][-]
Abstract: Two of the three new pillars of the European Union Common Fisheries Policy (EU Regulation 1005/2008; EU Regulation Proposal 2008/0216 (CNS)) were explicitly developed to address the illegal, unreported and unregulated fishing concern. These regulations attempt to introduce market monitoring measures that prevent IUU fish from entering legitimate trade channels in the Community. The leading purpose of this study was twofold: to analyse if the traceability related provisions of these two legal documents are relevant for IUU fishing deterrence, and to test if they fulfil de lege lata the traceability requirements of the chain of custody. In order to achieve these aims, a novel analytical tool that was suitable for the dual purposes had to be constructed. Model 1 was conceived to identify the overlapping of the necessary data for identifying IUU components (actors or products) with the traceability data recorded in the documentation imposed by the legal provisions at each critical traceability control point. Model 2 was designed to identify the fulfilment of the chain of custody requirements along the traceability control points. The present findings indicate that the traceability data retained according to the new legal EU norms have little relevance to be used effectively in deterrence of IUU operations. Similarly, the system put into place by both legal documents does not fulfil the requirements of a traceability scheme. Although the two analytical models utilized are preliminary, they can be further developed to improve comprehensiveness and depth of scrutiny. The models developed and the main findings of the study are of interest to both Community and third-country entities involved in a way or another in IUU fishing deterrence, traceability in fish supply chains or legislation development. Future studies should focus on the design of a traceability system for fishery products that fits the purpose of IUU fishing deterrence under a de lege ferenda approach. URI: http://hdl.handle.net/10037/2002 File(s) in this item: 1
thesis.pdf (2.460Mb) -
Bortier-Verstraaten, Mabel Borteley (Master thesis; Mastergradsoppgave, 31-May-2002)[+][-]
Abstract: The commercial tuna fishery of the East Atlantic and like wise the Ghanaian tuna fishery are based on the harvests of Bigeye, Skipjack and Yellowfin. In Ghana, baitboats and purse seiners commercially harvest these species of tuna. This study analysed the CPUE for the Ghanaian tuna fishery. The analysis was made for the three species and also for the two vessel types. The effort was standardized to large purse seiner days. The results when compared to the CPUE per species for the East Atlantic revealed that the Ghanaian vessels (1980 – 2000) were in some cases up to 40 times more efficient than large purse seiners in the East Atlantic (1967-1980). A single species bioeconomic analysis was conducted for each of the three species using biological parameters adopted from Conrad and Adu-Asamoah (1986). This showed that present harvest levels of Skipjack and Yellowfin for the East Atlantic region were in excess of the open access equilibrium. Thus a decline in future harvest levels of Skipjack and Yellowfin is expected. Sustainable economic rents calculated for the two-vessel types revealed that, bioeconomically, baitboats are more profitable than purse seiners. It was observed that the FAD’s might be the main cause of changes in the species composition ratio of the tuna catches over the past decade. URI: http://hdl.handle.net/10037/305 File(s) in this item: 1
thesis.pdf (1.408Mb) -
Colindres, Clarence Oliver Gonzales (Master thesis; Mastergradsoppgave, 13-Jun-2006)[+][-]
Abstract: Fishing continues to be the main source of income in the Pearl Lagoon Basin in Nicaragua. Currently the fishermen in the area have expressed growing concern about the shrimps stocks. Over the past years it has become increasingly clear that the fish and shrimp stocks are being exhausted, severely over-fished and experiencing a serious decline. This thesis examines the catch compositions (shrimps and by-catch) of three mesh sizes of the Cast net gear employed in the fishery through sampling during the months of July and August, as well as analyzes the current situation of the shrimp inside the lagoon through primary (interviews) and secondary (books, journals, articles, reports, etc.) data. The data samples of the experiment with the different mesh sizes identified in the thesis were analyzed using standard software applying a trouser trawl method to determine the selectivity curve. Single factor ANOVA tests were use to distinguish significant differences between lengths. Significant differences were also tested combining the three different mesh sizes applying the SPSS turkey multi comparison computer program model. The findings were discussed and compared with a previous selectivity study accomplished in the lagoon. The thesis concludes that gears with ½ inch mesh size were vulnerable to the species during these months by retaining low weight and smaller length shrimp compositions (70% of the capture is between 5 and 8 cm total length). 1 inch and 1½ inch mesh sizes showed a general improvement in the selective performance of the gear (approximately 90% of the captured shrimps were between 11 and 14 cm). The main secondary findings show that local people are employing small gear mesh sizes in the lagoon, especially those whose sustainability livelihoods are significantly threatened with very few opportunities of survival; most obvious those who live in the more remote areas. URI: http://hdl.handle.net/10037/313 File(s) in this item: 1
thesis.pdf (1.012Mb) -
Dyspriani, Polite (Master thesis; Mastergradsoppgave, 29-May-2007)[+][-]
Abstract: Shrimp world production in the last few years has shown very high growth rates. It is marked by an increasing of production volume, and by shifting from capture to aquaculture fisheries within the production system. This has occurred mostly regarding to the brackish water pond. For some years, the government has had to face hard choices in order to ensure shrimp aquaculture developed sustainable. The desire and temptation to pursue the excessive development of shrimp production as a source of foreign currency often conflicted with concerns for ecosystem health, social justice, food safety, livelihoods and food security. The Fisheries Revitalization Program is one of the main driving forces behind establishing a governance system that allows the stakeholders to play an effective role in managing fisheries sustainable. The program utilizes political support to encourage sustainable livelihood by creating economic growth, providing job and alleviating poverty. The Fisheries Revitalization Program focuses on the development of three important economic commodities, namely shrimp, skipjack and seaweed. The study focuses on the shrimp revitalization program, by using the governance concept to analyze how the mechanisms and effects of the program so far. The findings are the contributions and commitments from the three societal institutions (state, market and civil society) needed to play roles in the shrimp governance system, and local institution needs to be developed. Key words: governance, revitalization, sustainable, local institution URI: http://hdl.handle.net/10037/1008 File(s) in this item: 1
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Egyir, Isaac Kwasi (Master thesis; Mastergradsoppgave, 15-May-2012)[+][-]
Abstract: Ghana’s find of oil and gas in commercial quantities marks the beginning of a billion-dollar industry. The exploration and production of it is a major industrial development but its negative impacts on fisheries can never be underestimated. The research questions to be answered are: how is it likely that the fisheries in Ghana will be affected by the expanding oil and gas activities? What kinds of measures have been introduced to safeguard the fisheries? What can be done to mitigate harms and to secure a peaceful co-existence between the petroleum and the fisheries sectors? Purposive and random samplings were used to select one hundred and eighty respondents in the Cape Three Points community during field survey in the month of June and July 2011. Key informants were interviewed and field observations were also made. The result shows that standard of living of respondents is generally low and they lack social amenities in the community. The general perception of the respondents (75.6 %) is positive because they are expecting the oil and gas activities to boost their livelihood activities and increase income. The majority of the respondents with positive perception are women engaged in fish related activities, petty trading and farming. 36.2% of respondents asserted that the oil and gas activities would bring great loss in the quantity of fish catch. These were mostly fishermen and fishmongers. Even though the 36.2% is quite marginal, it still confirms the assertion that fish catch may reduce. Restriction imposed by naval officials in charge of the rigs, the incident of oil spillage and pollution are other major concern by the respondents. The government is enacting some laws and policies which can safeguard the fisheries if well implemented, however local communities and stakeholder involvement is not adequate. Also the institutions lack the human resources and the capacity to implement these policies. Recommendations are therefore made to ensure peaceful co-existence between fisheries and the oil and gas sector. Keywords: Oil and gas activities, fisheries, mitigation, livelihoods, Western Region, Ghana URI: http://hdl.handle.net/10037/4356 File(s) in this item: 1
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Elago, Panduleni N. (Master thesis; Mastergradsoppgave, 07-Jun-2002)[+][-]
Abstract: Two hake species are caught off the coast of Namibia. These are Merluccious capensis and Merluccius paradoxus, and they are not distinguished between in catches . Two fishing fleets harvest hake, these are trawlers and longliners. In this study, the focus has been on the biological and economic characteristics of two different fishing methods. The Pella and Tomlinson surplus production model was used, and the parameters estimated by applying time series of catch and effort data. Revenue and cost were estimated in order to do an economic assessment of the hake fishery. The results from the model analysis suggests a higher benefits (economic rent) from the longline fishery only, with high catch rates, high effort, revenue. The model indicates that the level of stock from both longlining and trawling are operating under a sustainable level of fishing effort. The maximum theoretical resource rent of the trawl and longline fisheries amounts to N$891 million and N$1,7 billion respectively. However from the current hake stock we will expect a decrease in catch in a long run (trawl fishery) with a stable or even a decreased effort from today’s fishery for Namibian hake to be at the level of maximum economic yield of effort and catch. The higher rent generated by longliners is due to the high price they receive for their landings which is usually exported; and the different selection pattern from the two fishing fleets. Thus, a difference of N$802 million will accrue to longliners according to the model results. URI: http://hdl.handle.net/10037/312 File(s) in this item: 1
thesis.pdf (347.1Kb) -
Falk-Petersen, Jannike (Master thesis; Mastergradsoppgave, 28-May-2004)[+][-]
Abstract: Barents Sea ecosystem is limited. Due to the information available on benthos the Ecopath model of Sørfjord, Northern Norway, was used to investigate possible trophic changes with introduction of king crab to the model. A literature study of the king crab was conducted to find information on diet, mortality, consumption rate and other life history parameters required by the model. A short introduction to biological invasions was also included. The Ecopath with Ecosim software was used as a modelling tool to investigate factors allowing for growth of king crab as well as potentially controlling their biomass. Possible food-web effects of king crab invasion on the Sørfjord ecosystem was also investigated. Knowledge gaps identified through the exercise and management implications were discussed. A biomass of 1.2 t km-2 small and 2.8 t km-2 large king crabs was introduced to the Sørfjord model. The modelling exercise indicated that a resource opportunity, in the form of benthic production, could allow for growth of the king crab in Sørfjord. Mammals could have a negative impact on large king crab abundance through predation, while fish predation is expected to have minor effects on king crab biomass. King crabs are expected to have a negative effect on the benthic community through predation, but limited impact on the pelagic community. King crab abundance could be controlled by fishing large king crabs. A change in fishing of other commercial fish species is not expected to have an impact on king crab biomass. Knowledge gaps identified from this exercise includes population structure, biology and food preference of king crab. Production and interactions within the native benthic community should also be investigated further to understand possible impacts of king crab invasion. URI: http://hdl.handle.net/10037/316 File(s) in this item: 1
thesis.pdf (1.010Mb) -
Hamenoo, Edmond Kwablah (Master thesis; Mastergradsoppgave, 13-May-2011)[+][-]
Abstract: Aquaculture in Ghana has over the years been little productive despite earlier claims about the high potential of the country. These claims are supported by an abundance of latent natural resources that can support large scale commercial production and the existence of a strong traditional market for fish products. A survey of consumer behavior in the local market for tilapia and fish in general was conducted in Ghana. The data were subjected to tabulation and multivariate analysis to assess the availability of market for tilapia and the determinants of its demand among different income earners. Local production according to the survey is not able to satisfy the market. Whereas low income earners and large families are avid fish consumers, it is mostly the relatively small group of high income earners that can afford tilapia at current retail prices. The performance of Ghana was measured in terms of the relative competitiveness of the value chain of tilapia in China, Egypt and the Philippines, as well as with prices on the global market. All the three countries profiled had a cost advantage and this was a result of wide differences in the cost of some factors of production or their relative scarcity in Ghana. The cost of importing fish feed, high interest rate on credit and poor production technology were some of the bottlenecks that greatly reflected on first sale prices. While a kilogram of fish feed for instance cost US$ 0.3 in Egypt and US$ 0.53 in China, the average price in Ghana is US$ 1.96. The export price of frozen tilapia fillet from China is about US$ 1 while the retail price of frozen whole tilapia in Ghana is about US$ 6.5. Tilapia from any of the countries surveyed would be more competitive to that of Ghana not only in the global market but also on the Ghanaian local market given the current price differences. URI: http://hdl.handle.net/10037/3530 File(s) in this item: 1
thesis.pdf (1.034Mb) -
Hamid, Lemia M.O (Master thesis; Mastergradsoppgave, 22-May-2003)[+][-]
Abstract: In recent years increased attention has been focussed on fish vaccines and vaccination against diseases in farmed fish. In this study, efficacy and side effects of vaccination against atypical furunculosis in Atlantic cod (Gadus morhua L.) were studied in an experimental trial by using different adjuvants. The different adjuvanted vaccines were administered by intraperitoneal injection (i.p.) to Atlantic cod. The adjuvants used were CpG DNA, Aluminium hydroxide (Alhydrogel), and Freunds incomplete adjuvant (FIA). Efficacy of the vaccines and side effects were determined 12 weeks post vaccination, whereas serum antibodies were measured 15 weeks post vaccination. Vaccination of Atlantic cod against atypical furunculosis protects the fish and elicits specific antibody responses to experimental infection with atypical A. salmonicida. The atypical A. salmonicida bacterin alone resulted in very good protection (RPS=75%), and addition of adjuvant alone or in combination did not improve the protection significantly. This indicates that Atlantic cod can be protected against atypical furunculosis through non-adjuvanted vaccines. The injection of FIA alone gave non-specific protection, while the adjuvants CpG DNA and Aluminium hydroxide did not give any non-specific protection. The group, which received CPG DNA alone, had a higher mortality (57%) than the saline control group (53%). High specific antibody responses were demonstrated in all groups vaccinated with A. salmonicida bacterin. The responses were strongest in the groups, which received A. salmonicida in FIA. The study also assessed the side-effects 12 weeks vaccination. The vaccines containing FIA showed the most sever side-effects among the vaccinated group. Aluminium hydroxide showed a less degree of the intraabdominal side effects compared to FIA, but a delay in fish growth was observed. URI: http://hdl.handle.net/10037/330 File(s) in this item: 1
thesis.pdf (606.3Kb)
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