Munin: Browsing Doktorgradsavhandlinger (BFE-fak) by Author

Management of the alien invasive red king crab Integrating natural and social science perspectives

Falk-Petersen, Jannike (Doctoral thesis; Doktorgradsavhandling, 12-Jun-2012)

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Abstract:	The red king crab (Paralithodes camtschaticus) is a highly valuable resource that also represents a potential threat since it is an alien invasive species in the Barents Sea ecosystem. This thesis explores the use of different interdisciplinary frameworks to analyse how ecological, social and economic concerns could be accounted for in deciding on how the king crab should be managed in the Norwegian part of the Barents Sea. Clarification of terminology used in invasion biology and systematisation of ecological information in order to establish the ecological knowledge base for management forms the basis for further analysis. Bio-economic modelling and discourse analysis are used to explore how uncertainty and the range of services the ecosystem provides can be incorporated in management. Finally the use of ecosystem service frameworks to integrate ecosystem and social science research in ecosystem based management is discussed. The ecological review revealed numerous knowledge gaps in our understanding of how the king crab interacts with native biota. It also identified negative impacts on benthic ecosystems that provide supporting services, and on provisioning services through predation on eggs of commercial fish. Bio-economic analysis illustrated the need to identify the correct relationship between crab stock size and ecosystem damage. It also showed that optimal harvest of king crab cannot be reconciled with the Barents Sea management goal of securing the ecosystem structure. The discourse analysis showed that people recognise both positive and negative impacts of the crab on supporting, provisioning and cultural services. In addition the impacts on ecosystem services we do not have the knowledge to value today, or option values, were important in forming people’s perception on how the crab should be managed. This thesis demonstrates that while the natural sciences have a clear role to play in establishing the ecological knowledge base, uncertainty and the need to account for stakeholder concerns calls for integration of social science research in the management process. Ecosystem service frameworks can be useful tools for identification, integration and evaluation of such information.
Description:	The papers of this thesis are not available in Munin: 1. Falk-Petersen, J, Bøhn, T. and Sandlund, O.T.: 'On the numerous concepts in invasion biology', Biological Invasions (2006), 8: 1409-1424. Available at http://dx.doi.org/10.1007/s10530-005-0710-6 2. Armstrong, C.W. and Falk-Petersen, J.: Habitat-fisheries interactions : a missing link?', ICES Journal of Marine Science (2008), 65: 817-821. Available at http://dx.doi.org/10.1093/icesjms/fsn092 3. Falk-Petersen, J., Renaud, P. and Anisimova, N.: 'Establishment and ecosystem effects of the alien invasive red king crab in the Barents Sea', ICES Journal of Marine Science (2011), 68 (3): 479-488. Available at http://dx.doi.org/10.1093/icesjms/fsq192 4. Falk-Petersen, J. and Armstrong, C.: 'To have one’s cake and eat it : managing the alien invasive red king crab stock' (submitted manuscript). 5. Falk-Petersen, J.: 'Option lost or opportunity gained? Perceptions on the Barents Sea red king crab invasion', (submitted manuscript).
URI:	http://hdl.handle.net/10037/4236

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thesis.pdf (1.101Mb)

Reproductive behaviour and sex trait allocations in an external fertilizer – the Charr (Salvelinus alpinus)

Figenschou, Lars (Doctoral thesis; Doktorgradsavhandling, 12-May-2010)

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Abstract:	This thesis illuminates several aspects of mate choice and sexual selection in a species with external fertilization and no parental care. At a general level we have contributed to the basic framework within evolutionary biology and ecology and at a more specific level, as the proximate mechanisms controlling the associations between immune response, parasite intensities and traits indicative of sperm quality are not straightforward, we examined the effect of increased immunological activity on sperm traits. Our results have established the significance of male social status, and in the two inter-disciplinary studies, showed that parasitized and infected males seem to invest more in sperm quality, less in ornamental development and adapt to sperm competition (i.e., subordinate mating tactic). Thus, as reproductive decisions in charr seem to be strongly influenced by parasites and antigens, host parasite co-evolution may have been a significant mechanism in the maintenance and evolution of both male sexual behaviour and ornamentation.
Description:	Papers number 1, 3, 4, 5 and 6 of the thesis are not available in Munin: 1. Figenschou, L., Folstad, I. & Liljedal, S.: «Lek fidelity of male Arctic charr», Canadian Journal of Zoology, 82(2004): 1278-1284 (National Research Council Canada - publisher's restrictions). Available at http://dx.doi.org/10.1139/z04-106 3. Rudolfsen, G., Figenschou, L., Folstad, I., Tveiten, H. & Figenschou, M.: «Rapid adjustments of sperm characteristic in relation to social status», Proceedings of the Royal Society of London, Series B-Biological Sciences, 273(2006): 325-332 (publisher's restrictions). Available at http://dx.doi.org/10.1098/rspb.2005.3305 4. Figenschou, L., Rudolfsen, G., & Folstad, I.: «Female Arctic charr do not show apparent benefits from exposing their eggs to sperm from dominant males», Journal of Fish Biology, 71(2007): 284–289 (Wiley - publisher's restrictions). Available at http://dx.doi.org/10.1111/j.1095-8649.2007.01477.x 5. Figenschou, L., Skau, P.A., Folstad, I., Rudolfsen, G., Hanssen, S.A., Kortet, R., Killie, J.E., Oskam, I. & Strand, H.: «Parasite intensities and male social status as modifiers of sperm production and sperm swimming speed in the Arctic charr (Salvelinus alpinus)» (manuscript) 6. Figenschou, L., Skau, P.A., Folstad, I., Rudolfsen, G., Hanssen, S.A., Kortet, R., Killie, J.E. & Strand, H.: «Immune activation leads to reproductive compensation in Arctic charr (Salvelinus alpinus)» (manuscript)
URI:	http://hdl.handle.net/10037/2639

File(s) in this item: 2

paper_2.pdf (286.0Kb)

thesis.pdf (2.009Mb)

PLGA and PLA particles as vaccine delivery systems for Atlantic salmon : a study on formulation and use with an emphasis on immune responses

Fredriksen, Børge Nilsen (Doctoral thesis; Doktorgradsavhandling, 07-Jun-2012)

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Abstract:	Vaccines are regarded as the safest and most cost-effective strategy to prevent infectious diseases. For some diseases, vaccine improvements are required as protection levels are still inadequate. The key to solving this challenge might lie in the development of more efficacious vaccine delivery systems and adjuvants. Poly (lactide-co-glycolide) (PLGA) is a biodegradable polymer which has an extensive safety record in biological systems and possesses immunological adjuvant properties as injectable particles. In the present work, micro- and nanoparticles of PLGA and PLA were explored as a vaccine delivery system in Atlantic salmon (Salmo salar). The overall objectives were to investigate their adjuvant abilities in provoking innate and adaptive immune responses, forming antigen depots and inducing protective immunity in a challenge test with infectious pancreatic necrosis virus (IPNV). Formulation parameters in preparation of polymeric particles were systematically optimized (paper IV) to achieve stable PLGA particle products containing co-entrapped model antigens and β-glucan (paper I and II), or virus particles of infectious pancreatic necrosis virus (IPNV) (paper III). Post immunization potency of nanoparticles (300-400 nm) was demonstrated by their ability to induce early innate responses (day 2, 4 and 8) at transcription levels equal to or higher than the oil-adjuvanted formulation (paper I). Temporal differences in expression levels of innate markers were observed, suggesting rapid systemic distribution of particles (paper I). By tracing of isotope labelled proteins, nanoparticles (˂ 1000 nm) were found to localize antigens in the head kidney while micro-sized (~ 8 µm) particles generally retained antigen at the injection site. Irrespective of size, particles made of polymers with high molecular weight (MW) generally had superior depot capabilities compared to their low MW counterparts (paper II). Adaptive immune responses to immunization were assessed by QPCR and ELISA. T cell markers were not differentially expressed at the selected early time points (paper I), but at day 60 and 75 antibody responses were found to be elevated (paper II and III). In a dose-response study, micro- but not nanoparticles were demonstrated to be equally potent compared to the oil-adjuvanted control group with regard to induction of antibody responses. Long-term antibody responses induced by particles were generally less robust and therefore declined towards the end of the experimental period (120 days), while responses induced by the oil-adjuvanted formulation progressively increased. Following immunization, antibody responses were not related to polymer qualities or the ability of particles to depot or distribute antigens. Scoring of side effects demonstrated excellent safety profiles for the particle formulations (paper II and discussed in paper V). In paper III, vaccine efficacy was tested in a cohabitation challenge with IPN. Survival rates for the nanoparticle vaccinated groups were comparable to the non-vaccinated control fish and demonstrated that their ability to induce protection against IPN was inferior to the oil-adjuvanted vaccines. Virus re-isolation from head kidney and blood during the challenge period did however demonstrate some level of protection as the nanoparticle vaccinated groups were able to delay the IPNV infection. In the presented studies, the principal adjuvant properties of PLGA particles in Atlantic salmon have been demonstrated to include their capacity to induce strong innate responses and provide antigen depots for long-term delivery of antigens. In addition, indication of particle presence in lymphoid organs was an interesting finding that could suggest a certain targeting effect to phagocytic cells. To achieve a better understanding of how PLGA particles may be used to direct immune responses in salmon, more detailed studies on particle qualities-cell interactions/responses are required.
Description:	Papers 1-4 of this thesis are not available in Munin: 1. B.N. Fredriksen, K. Sævareid, L. McAuley, M.E. Lane, J. Bøgwald and R.A. Dalmo.: 'Early immune responses in Atlantic salmon (Salmo salar L) after immunization with PLGA nanoparticles loaded with a model antigen and β-glucan', Vaccine (2011) 29(46):8338-8349. Available at http://dx.doi.org/10.1016/j.vaccine.2011.08.087 2. B.N. Fredriksen and J. Grip.: 'PLGA/PLA micro- and nanoparticle formulations serve as antigen depots and induce elevated humoral responses after immunization of Atlantic salmon (Salmo salar L)', Vaccine (2012) 30(3):656-667. Available at http://dx.doi.org/10.1016/j.vaccine.2011.10.105 3. H.M. Munang‟andu, B. N. Fredriksen, S. Mutoloki, B. Brudeseth, T.Y. Kuo, I. S. Marjara, R.A. Dalmo and Ø. Evensen.: 'Comparison of vaccine efficacy for different antigen delivery systems for infectious pancreatic necrosis virus vaccines in Atlantic salmon (Salmo salar L)' (submitted manuscript). 4. B.N. Fredriksen, L.B. Hølvold, J.Bøgwald and R.A. Dalmo.: 'Optimization of formulation variables to increase antigen entrapment in PLGA particles' (submitted manuscript).
URI:	http://hdl.handle.net/10037/4153

File(s) in this item: 2

paper_5.pdf (223.3Kb)

thesis.pdf (1.720Mb)

Plant regulatory networks : RNA binding proteins as mediators of communication between DNA containing compartments by dual targeting

Fuss, Janina (Doctoral thesis; Doktorgradsavhandling, 11-May-2012)

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Abstract:	The endosymbiosis-derived organelles within a plant cell, plastids and mitochondria, have to be equipped with a certain set of proteins to be fully functional. This set of proteins is encoded by different genomes: the organellar genomes and the nuclear genomes. This setup poses some interesting challenges for the regulation of gene expression and protein transport. On the one hand, the targeting signals that transport proteins to the organelles have to be highly specific and on the other hand, the communication between the DNA containing compartments to coordinate their gene expression has to be transmitted somehow, not only from the nucleus but also from the organelles back to the nucleus. In this thesis, two prediction programs are introduced. One of them can predict dual targeted proteins to both organelles (ATP, ambiguous targeting predictor) and the other one is species- specific for Physcomitrella patens (GTP_Pp; green targeting predictor – P. patens-specific). The first predictor can help to gain a more complete picture of the proteins potentially present in the organelles. With the help of that predictor, we predicted that the amount of proteins with dual targeting signals is higher than anticipated and that we to date know only a minor part of actually dual targeted proteins. The second predictor can help to answer the question on the evolutionary consistency of targeting signals within the plant kingdom and the importance of having species-specific approaches in analyzing protein targeting. We actually observed a surprisingly big difference in composition and recognition of mitochondrial and dual-targeting protein signals, which led to the conclusion, that species-specific approaches always should be considered as the optimal option for both, in silico and in vivo experiments. The second part of this thesis focuses the mechanisms of communication between nucleus and the organelles, especially the plastid possibly mediated by dual targeting. We chose several plastid RNA-/DNA-binding proteins to analyze their sub-plastidic localization and their potential additional nuclear localization. Those candidates were AtWHY1 (Arabidopsis thaliana Whirly1), four members of the AtcpRNP (chloroplast ribonucleoprotein) family and AtEF-Tu (elongation factor thermo-unstable). The analyzed members of the AtcpRNP family reflect their described multiple functions within the plastid also in a multiple localization pattern. Furthermore, we were able to show interactions of different members of the AtcpRNP family by yeast-two-hybrid interaction assays. The localization pattern of AtEF-Tu was very similar to the one observed for the AtcpRNPs, which indicated, together with a confirmed localization within the transcriptionally active chromosome, a multiple function for AtEF-Tu. The sub-plastidic localization data suggest overlapping networks of activity for the proteins by observed co-localizations. This was also shown with respect to several marker proteins for plastid functions. For AtEF-Tu and the AtcpRNPs, we also showed experimentally that a second localization in the nucleus is possible for the mature protein, which makes them interesting candidates for a possible mediation of plastid signals to the nucleus next to AtWHY1. For AtWHY1, we were able to show an effect of the DNA binding domain on the known localization pattern which seemed to reflect an aberration in transport processes through the envelope. This offers a potential regulatory mechanism that needs to be explored in detail in the future.
Description:	Papers 1, 3, 4 and 5 are not available in Munin: 1. Mitschke J, Fuss J, Blum T, Hoglund A, Reski R, Kohlbacher O and Rensing SA.: 'Prediction of dual protein targeting to plant organelles', New Phytologist (2009), 183(1): 224-235. Available at http://dx.doi.org/10.1111/j.1469-8137.2009.02832.x 3. Herrmann U, Fuss J, Krupinska K and Krause K.: 'Moonlighting in plastids : translation elongation factor EF-Tu is a component of chloroplast transcriptionally active chromosomes' (manuscript I submitted to Current Genetics). 4. Fuss J, Krause K.: 'Co-Localization and interaction of ribonucleoproteins in chloroplasts of Arabidopsis thaliana' (manuscript II). 5. Fuss J, Liegmann O, Krause K and Rensing SA.: 'Can Arabidopsis thaliana read the messages from Physcomitrella patens and vice versa? : an analysis on the conservation of targeting signals' (manuscript III submitted to New Phytologist). 6. Fuss J, Krause K.: 'The DNA binding domain of a Whirly protein from Arabidopsis thaliana is engaged in protein translocation across the plastid envelope membrane' (manuscript IV).
URI:	http://hdl.handle.net/10037/4154

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thesis.pdf (1.509Mb)

Vole population cycles and the role of colonisation

Glorvigen, Petter (Doctoral thesis; Doktorgradsavhandling, 06-Dec-2012)

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Abstract:	The multiannual population cycles in small rodents have triggered an intense debate between proponents of population-intrinsic and community-extrinsic factors as the cycle generating mechanisms. A well-known challenge is the apparent absence of vole individuals during the low phase of the population cycle and the fact that most studies addressing vole and lemming behaviour and demography are conducted at high to moderate population densities. Overall this thesis aim to (1) present new insight for the least studied phase(s)of the vole population cycles: specifically the role of colonisation processes in the transition from small isolated populations in the low-phase to the spatially extensively distributed populations in the peak phase of the cycle, and (2) provide an updated view on how population-intrinsic and community-extrinsic processes may interact during the vole population cycles. The first experiment documented that colonisation is a beneficial strategy in female bank voles (Myodes glareolus) compared to immigration. The second experiment demonstrated that the first born cohort of root voles (Microtus oeconomus) emigrating in early summer have large capacity for colonising spatially scattered habitat patches – a capacity that explains the fast recolonistation of empty habitat space following crashes in cyclic populations. These experimental results also gave evidence for presence of social fences around high quality habitats at low population density. Hence, in the increase phase voles seem to actively search for vacant habitats and settle in them conditional on habitat quality and population density. An observational study of a riparian mainland-island root vole metapopulation confirmed that such patchy populations with cyclic dynamics may be subject to extensive occupancy dynamics. However, owing to high capacities for dispersal and habitat tracking, voles rapidly colonised the high quality islands across the entire metapopulation landscape that previously had gone extinct due to demographic (small population size) and environmental (high water levels) stochasticity. In total, the experimental and observational studies show that spatially scattered (sub)populations that have survived the crash phase are able to provide colonists to remote habitat patches embedded in hostile matrix and thus pave the way to a new increase and peak phase. The updated view on the causes of population cycles in voles emphasises the important role of dispersal (colonisation) and sociality in all phases of the cycle. It is not claimed that intrinsic mechanisms, either alone or in interactions with extrinsic factors, are necessary for generating multiannual cycles. Rather that the interaction between extrinsic and intrinsic factors likely contribute to shape rodent population dynamics, and that different innate propensities for sociality and dispersal among different rodent species may be related to interspecific variation in topology of the cycles (i.e. cycle shape and amplitude) and degree of spatial population synchrony.
Description:	The papers of this thesis are not available in Munin: 1. Glorvigen, P., Bjørnstad O.N., Andreassen, H.P. and Ims, R.A.: 'Settlement in empty versus occupied habitats : an experimental study on bank voles', Population Ecology (2012), vol. 54:55-63. Available at http://dx.doi.org/10.1007/s10144-011-0295-0 2. Glorvigen, P., Gundersen, G., Andreassen, H.P. and Ims, R.A.: 'The role of colonization in patchy population dynamics of a cyclic vole species' (manuscript). 3. Glorvigen, P., Andreassen, H.P. and Ims, R.A.: 'Relative importance of habitat geometry, habitat quality, population size and environmental stochasticity on occupancy dynamics in a riparian mainland-island root vole metapopulation', (manuscript). 4. Andreassen, H.P., Glorvigen, P., Rémy, A. and Ims, R. A.: 'New views on how population-intrinsic and community-extrinsic processes interact during the vole population cycles' (manuscript)
URI:	http://hdl.handle.net/10037/4655

File(s) in this item: 1

thesis.pdf (2.547Mb)

Staying alive : the survival and importance of Atlantic salmon post-spawners

Halttunen, Elina (Doctoral thesis; Doktorgradsavhandling, 19-Aug-2011)

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Abstract:	Summary Atlantic salmon (Salmo salar L.) repeat-spawners might play an important role in population persistence by increasing both total recruitment and long-term stability of a population. This is because repeat spawners return at larger sizes and with greater fecundity than first time spawners, and the large majority of repeat-spawners are females. Nevertheless, little knowledge exists of this potentially significant population sub-unit. We conducted a four-year field study in the River Alta, Northern Norway, using acoustic and radio telemetry combined with scale sample analysis and mark recapture, with the aim of 1) assessing the survival and migration patterns after spawning, 2) assessing the post and repeat-spawner mortality in the fisheries, and 3) quantifying the returning rate of post spawning females. These results were further used in combination with historical catch-records from both sea and in-river fisheries to 4) model the repeat spawning rate in the female population and the significance of repeat spawning for egg production during fluctuating maiden runs. We found that 1) survival after spawning and early marine migration was high (63-80% and 96%, respectively), and that the post-spawners (kelts) in best condition waited longest in the river before migrating. 2) The fisheries mortality was low (4%) when exiting the river and fjord, and moderate (11 %) when re-entering the fjord and river upon return. 3) Female survival until spawning was on average 32 %, and 4) according to model simulations, on average 20% of the female population consisted of repeat-spawners, which might have an important stabilizing function reducing fluctuations in a population by contributing an average of 27% (2%-59%) of all the eggs spawned in the river. We conclude that the post-spawners have high survival both in the river and the sea despite their weakened condition after spawning and overwintering in the river, and that repeat-spawners might contribute significantly to Atlantic salmon production. Their numeric and genetic contribution might be especially important during declining and fluctuating populations as a buffer against poor maiden recruitment years. Therefore post- and repeat-spawners are worthy of special conservational attention and management measures.
Description:	The papers of this thesis are not available in Munin: 1. Elina Halttunen, Audun H. Rikardsen, Jan G. Davidsen, Eva B. Thorstad and J. Brian Dempson: 'Survival, migration speed and swimming depth of Atlantic Salmon Kelts during sea entry and fjord migration', Reviews: Methods and Technologies in Fish Biology and Fisheries (2009) Volume 9, Part I, Part 1, 35-49. Available at http://dx.doi.org/10.1007/978-1-4020-9640-2_3 2. Elina Halttunena, Audun H. Rikardsen, Eva B. Thorstad, Tor F. Næsje, Jenny L.A. Jensen and Øystein Aas: 'Impact of catch-and-release practices on behavior and mortality of Atlantic salmon (Salmo salar L.) kelts', Fisheries Research (2010) vol 105, 141–147. Available at http://dx.doi.org/10.1016/j.fishres.2010.03.017 3. Elina Halttunen, Jenny Lovisa Alexandra Jensen, Tor Fredrik Næsje, Jan Grimsrud Davidsen, Eva Bonsak Thorstad, Cedar Marget Chittenden, Sandra Hamel, Raul Primicerio and Audun Håvard Rikardsen: 'State-dependent migratory behaviour of post-spawned Atlantic salmon (Salmo salar)' (unpublished paper). 4. Elina Halttunen, Audun Håvard Rikardsen, Ola Ugedal, Eva Bonsak Thorstad, Jenny Lovisa Alexandra Jensen and Tor Fredrik Næsje: 'The significance of repeat spawning for the production of Atlantic salmon (Salmo salar)' (unpublished paper).
URI:	http://hdl.handle.net/10037/3536

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thesis.pdf (6.563Mb)

Cellular responses induced by environmental stress factors in Arctic Seabird chicks : Responses of the antioxidant defense system and autophagic lysosomal processes related to contaminant exposure and food restriction

Hegseth, Marit Nøst (Doctoral thesis; Doktorgradsavhandling, 29-Nov-2011)

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Abstract:	This PhD study has investigated how two commonly occurring environmental stress factors in the Arctic (periods with little food and exposure to halogenated organic contaminants) have had an impact on two important cellular defense mechanisms in Arctic seabirds. The antioxidant defense system and autophagic lysosomal responses in liver cells of Arctic seabird chicks have been studied. Samples were collected from three seabird species at Svalbard and Tromsø area: Black-legged kittiwake (Rissa tridactyla), northern fulmar (Fulmarus glacialis) and herring gull (Larus argentatus ), as well as samples from a feeding experiment with herring gull chicks. The findings show that there are major species differences, and that the antioxidant defense system and autophagic lysosomal responses in the seabird chicks are affected by factors such as diet, species-specific physiology and fasting, as well as high-grade contaminant exposure. Some of the effects of contaminant exposure were dose-dependent. The contaminant concentrations found in the birds in this study were relatively low. Hence, more pronounced effects could therefore be present in wild-living birds that have higher contaminant concentrations than birds in this study. Some of the cellular effects observed in this study have been associated with adverse health effects in other animal species. Additional studies of these cellular systems in seabirds are recommended in order to implement such analysis in regularly monitoring of seabird health status in the future and may contribute to improved management of the important seabird populations in these areas.
Description:	The papers of this thesis are not available in Munin: 1. Marit Nøst Hegseth, Lionel Camus, Lisa Bjørnsdatter Helgason, Raffaella Bocchetti, Geir Wing Gabrielsen and Francesco Regoli: 'Hepatic antioxidant responses related to levels of PCBs and metals in chicks of three Arctic seabird species', Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology (2011) 154: 28-35. Available at http://dx.doi.org/10.1016/j.cbpc.2011.02.008 2. Marit Nøst Hegseth, Lionel Camus, Stefania Gorbi, Francesco Regoli and Geir Wing Gabrielsen: 'Effects of exposure to halogenated organic compounds combined with dietary restrictions on the antioxidant defense system in herring gull chicks', Science of the Total Environment (2011) 409 (14):2717-24. Available at http://dx.doi.org/10.1016/j.scitotenv.2011.04.004 3. Marta K. Jansen, Marit Nøst Hegseth, Raffaella Bocchetti, Francesco Regoli, Geir W. Gabrielsen and Lionel Camus: 'Impact of Halogenated Organic Contaminant Exposure and Fasting on Antioxidant Defence System on the Kidney of Herring Gull Chicks' (manuscript) 4. Marit Nøst Hegseth, Francesco Regoli, Stefania Gorbi, Raffaella Bocchetti, Geir Wing Gabrielsen and Lionel Camus: 'Lysosomal and lipid-associated parameters in the livers of three species of arctic seabird chicks : Species differences and relationships with contaminant levels', Marine Pollution Bulletin (2011) 62(8): 1652-60. Available at http://dx.doi.org/10.1016/j.marpolbul.2011.06.011 5. Marit Nøst Hegseth, Stephania Gorbi, Raffaella Bocchetti, Geir Wing Gabrielsen, Francesco Regoli and Lionel Camus: 'Effects of contaminant exposure and food restriction on hepatic lysosomal and lipid associated parameters in Herring gull chicks' (submitted manuscript to Environmental Research)
URI:	http://hdl.handle.net/10037/3780

File(s) in this item: 1

thesis.pdf (1.633Mb)

Female life-history parameters in the introduced red king crab (Paralithodes camtschaticus, Tilesius 1815) in the Barents Sea : a study of temporal and spatial variation in three Norwegian fjords.

Hjelset, Ann Merete (Doctoral thesis; Doktorgradsavhandling, 28-Aug-2012)

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Abstract:	The red king crab (Paralithodes camtschaticus) was deliberately introduced to the Barents Sea by Russian scientists during the 1960s, with the purpose to improve coastal fishery and thus improve the local economy. Since the red king crab was caught for the first time in the Varangerfjorden area, the stock has increased in abundance and expanded westward inhabiting coastal areas along the coast of Finnmark from the Russian border in east to the area around Hammerfest in west. Today the population of red king crab supports a valuable fishery in the Barents Sea, representing an ex-vessel value of 150 million NOK in 2011. Several challenges are related to management of the red king crab, since it is an introduced species. The Norwegian management regime today has two goals, one is to keep a long term harvest within a geographical limited area and the second is to limit further spread of the crab. Basic knowledge is needed to meet both objectives, particularly knowledge on life-history traits. The main study area in this thesis has been three large fjords in Finnmark in northern Norway. There is a historical westward spread of the crab along the Norwegian coast, and it has been present in Varangerfjorden, Tanafjorden and Laksefjorden for about 35, 25 and 15 years respectively. Crabs have been sampled annually during scientific autumn cruises from 1994 until 2011. Size at maturity is a key life-history parameter in fishery management and should be monitored routinely. For female red king crabs this means the recording of presence or absence of eggs. In paper I the size at maturity was estimated in female crabs from each of the three fjords which constitute the main study area in this thesis. No temporal differences were seen and the size at maturity varied from 108 to 111 mm carapace length in the three fjords and was found to be generally higher than in native areas. Knowledge about the species individual fecundity gives information on size and number of offspring produced. Fecundity is closely related to life-history traits such as size at maturity, life-span and egg size. In this study both spatial and temporal patterns in fecundity and a reduction in individual egg weight was found. A main finding in paper II was a reduction in the individual fecundity during a part of the study period. An average female produced about 30 % less eggs in 2007 compared to 2002. Fecundity is the life-history parameters that respond most rapidly to changes in environment or other factors, such as fishery. The abundance estimates of red king crab females have increased in our area during the study period, but in the last two years, a decrease was observed in Tanafjorden and Laksefjorden. The stock size composition and the individual fecundity parameters established in paper II has been used in paper III to obtain a reproductive potential of the crab stock for the period 1995 to 2011. The male-only fishery and introduction of a female quota has had influence on the size composition and fecundity, and thus on the potential egg production in the stock. The study also showed that an observed reduction in size of large males was correlated to a size reduction of large females with a one year lag.
Description:	The papers of this thesis are not available in Munin: 1. Hjelset, A.M., Sundet, J.H. and Nilssen, E.M.: 'Size at sexual maturity in the female red king crab (Paralithodes camtschaticus) in a newly settled population in the Barents Sea, Norway', Journal of Northwest Atlantic Fishery Science (2009), 41:173-182. Available at http://dx.doi.org/10.2960/J.v41.m633 2. Hjelset, A.M., Nilssen, E.M. and Sundet, J.H.: 'Reduced size composition and fecundity related to fishery and invasion history in the introduced red king crab (Paralithodes camtschaticus) in Norwegian waters', Fisheries Research (2012), 121–122:73-80. Available at http://dx.doi.org/10.1016/j.fishres.2012.01.010 3. Hjelset, A.M.: 'Red king crab (Paralithodes camtschaticus) recruitment potential in Norwegian fjords' (manuscript)
URI:	http://hdl.handle.net/10037/4561

File(s) in this item: 1

thesis.pdf (2.496Mb)

Primary production and the relevance of small autotrophic and heterotrophic cells in marine arctic ecosystems

Hodal, Helene (Doctoral thesis; Doktorgradsavhandling, 02-Dec-2011)

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Abstract:	The Arctic is one of the least studied regions in the world and large changes in marine ecosystem dynamic are expected here because of the increasing air and ocean temperature. The central Arctic Ocean has for a long time been considered as a very low productive ecosystem, but recent estimates of primary production gives relatively high values. The shelves surrounding the Arctic Ocean are highly productive areas, especially the Barents Sea region, and a large part of arctic primary production occurs in these seasonally ice-covered regions. The relevance of small cells in arctic ecosystems has received increased attention the last two decades, and it is now accepted that the microbial food web play an important role also in the Arctic. To increase the knowledge on primary production and the relevance of small autotrophic and heterotrophic cells in the Arctic different field studies were conducted. Spring bloom dynamics (nutrients, phytoplankton, protozoans and in situ primary production) were investigated in Kongsfjorden (Svalbard) in April and May in 2002. During the multidisciplinary CABANERA-project three field campaigns in 2003-2005 to the marginal ice zone of the northern Barents Sea were conducted. Primary production was measured in situ for 24 hours at different stages of ice-edge blooms. Primary production and chlorophyll a measurements were fractionated in small (<10µm) and large cells (>10µm). During an expedition across the Arctic Ocean in August and September 2005 different biological parameters were measured (chlorophyll a, biogenic silica, particulate carbon and nitrogen, few zooplankton samples) together with the distribution of autotrophic and heterotrophic microbial biomass. Bacteria abundance was estimated using flow-cytometry and protists abundance was analyzed by epifluorescence microscopy after staining with DAPI. Protists were divided in different size categorize: < 2µm, 2-5µm, 5-10µm and 10-20µm. A seasonally study (January-September) of bacteria community structure and activity was conducted in a cold high latitude fjord (Balsfjord, northern Norway) in 2009 using fluorescence in situ hybridization (FISH) combined with microautoradiography (micro-FISH). In Kongsfjorden we found that the onset of the spring bloom was linked to the hydrographical situation during the sea ice break up. The peak of the spring bloom was found to vary between different years in both timing and intensity but will most probably occur between the middle-end of April and the middle of May. Primary production in 2002 persisted for a long time due to mixing with nutrient rich water masses. The ice edge phytoplankton bloom in the marginal ice zone of the northern Barents Sea was very heterogenic and no patterns in integrated primary production could be assigned to stages or latitudes. Subsurface (20-60m) primary production contributed with 24% to the total integrated primary production during ice edge blooms in the marginal ice zone, illustrating the importance of sampling in subsurface maxima. Small cells contributed with 46% to total primary production during ice edge blooms underlining the important role small cells can play as primary producers. Picoplankton (<2µm) abundance was high in the Arctic Ocean, and in the central part heterotrophic cells dominated (72%). Bacteria abundance was very low in the central part of the Arctic Ocean, but it is unknown whether this was caused by low growth rates or by high predation pressure. Bacteria were found to be highly active during summer in the Balsfjord underlining the important role they play in carbon turnover in the ocean. Bacteria belonging to Roseobacter were very active in assimilating DOM but they were not very abundant. This suggests that species specific predation may regulate the abundance of active bacteria. The main conclusion from the work included in this synthesis is that small cells are an important component of arctic food webs. Small cells need to be considered as important primary producers, also during spring blooms and ice edge blooms. We also found that bacteria need to be studied on single cell level to understand the underlying reasons for the dynamics that are observed on community levels.
Description:	Papers 2,3 and 4 are not available in Munin: 2. Hodal H and Kristiansen S.: 'The importance of small-celled phytoplankton in spring blooms at the marginal ice zone in the northern Barents Sea', Deep-Sea Research Part II (2008) 55: 2176-2185. Available at http://dx.doi.org/10.1016/j.dsr2.2008.05.012 3. Kristiansen S, Hodal H and Reigstad M.: 'Autotrophic and heterotrophic microbial biomass across the Arctic Ocean' (manuscript) 4. Hodal H, Kirchman D, Kristiansen S, Straza T.: 'Bacteria diversity and single-cell activity in a cold high latitude fjord (Balsfjord) from winter to late summer 2009' (manuscript)
URI:	http://hdl.handle.net/10037/3783

File(s) in this item: 2

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Metabolic fingerprinting applied in diatom taxonomy

Huseby, Siv (Doctoral thesis; Doktorgradsavhandling, 18-Jun-2012)

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Abstract:	The main aim of this thesis was to investigate if and how metabolic fingerprinting can be applied in diatom taxonomy. Even though both morphology and gene sequences have been shown to be appropriate tools in diatom taxonomy there are cases where these give contradicting results, like in the case of cryptic species. Cryptic species have similar morphology but are genetically different. Another issue with these two tools is that they do not offer much information about the function of a species, information that is interesting in light of for example ecology and management. Metabolomics investigates the metabolites synthesized by an organism. The metabolites synthesized at a certain moment in time will be a reflection of what genes are expressed at that time and will be a product of the organisms response to the environmental and biological conditions prevailing. Direct injection mass spectrometry was used to investigate the metabolic fingerprints of different, commonly occurring, northern diatom species. The method produces mass-to-charge ratios (markers) normally with a mass precision of four decimals. Reproducibility of the method was 80% with the direct injection method applied, using a decimal precision of 0.1. The results of the analysis showed that the different species shared between 26-67% of the total markers. Even species of the same genera showed a high diversity. The two species Chaetoceros furcellatus and Chaetoceros socialis only shared 30% of the total markers. For four out of six species the difference between species increased with decreasing temperature. The expected phylogeny of these six species could not be reflected by the metabolite data. Cryptic diversity has been documented within the so-called cosmopolitan species Chaetoceros socialis. We investigated this diversity between strains collected from two geographic areas; the northeast Atlantic and Arctic and from Mediterranean waters. Monoclonal cultures were cultivated at three different temperatures, and analyzed with the aid of morphology, LSU rRNA sequencing, growth rates, photosynthetic maximum quantum yield and metabolic fingerprinting. Comparison of gene sequences of the two groups showed an unequivocal difference, while only small morphological differences in spore morphology (not in the morphology of the vegetative cells) could be found between the two groups. At all three temperatures there were clear differences in growth and maximum quantum yield. The results from the metabolic fingerprinting also supported these findings. The clear genetic as well as functional differences does not support the cosmopolitan distribution of C. socialis and we therefore conclude that this species should be revised. The results, both from the comparison of metabolic fingerprinting between diatom species as well as within a pseudo cryptic diatom species, in my opinion, is in support of the use of metabolomics in diatom taxonomy. Our results underline the need of metadata, e.g. growth rates, in metabolomics studies. I also think that increased knowledge of functional traits of species, like metabolomics, could be implemented in ecological modeling, building a bridge between taxonomy and ecology. The results of this thesis are also relevant to bioprospecting. The higher chemical diversity between species found at the lower temperatures, would indicate that it could be beneficial to cultivate diatoms at low temperatures, close to zero, in search for bioactivities.
Description:	The papers of this thesis are not available in Munin: 1. Eilertsen H.C., Huseby S., Degerlund, M., Eriksen, G.K., Ingebrigtsen, R.A. and Hansen, E.: 'Sample storage effects on reproducibility of direct infusion high-resolution mass spectrometry (HRMS) microalgae extract analysis', (manuscript submitted to Limnology and Oceanography Methods). 2. Huseby, S., Hansen, E., Degerlund, M., Eriksen, G. K., Ingebrigtsen, R.A and Eilertsen, H.C.: 'Chemical diversity of six northern diatoms', (manuscript submitted to Journal of Applied Phycology). 3. Degerlund, M., Huseby, S., Zingone, A., Sarno, D. and Landfald, B.: 'Functional diversity in cryptic species of Chaetoceros socialis Lauder (Bacillariophyceae)', Journal of Plankton Research (2012), vol. 34, no. 5:416-431. Available at http://dx.doi.org/10.1093/plankt/fbs004 4. Huseby S., Degerlund M., Zingone, A. and Hansen. E.: 'Metabolic fingerprinting reveals differences between northern and southern strains of the cryptic diatom Chaetoceros socialis', (manuscript in revision in European Journal of Phycology)
URI:	http://hdl.handle.net/10037/4269

File(s) in this item: 1

thesis.pdf (2.740Mb)

Bacterial flagellin : a novel adjuvant for vaccine strategies

Hynes, Natasha (Doctoral thesis; Doktorgradsavhandling, 18-Oct-2011)

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Abstract:	Flagellin is the principal structural protein in the locomotive organ flagellum present on flagellated bacteria, and is known to be an important evolutionarily conserved PAMP. Flagellin has been shown to bind to the PRR TLR5 which induces innate immune system responses and signaling pathways. In mammals, much focus has been placed on this protein in vaccine studies for its possible function as an adjuvant. Flagellin (FlaD from Vibrio anguillarum) was recombinantly produced in two forms, full-length (FDL) and a truncated form (FDS) with portions of the N- and C-termini removed to prevent polymerization. Both forms of flagellin were tested alone and in combination with an antigen in a dose response study to determine the most effective dosage to produce a strong immune response. A polyclonal antibody for FDS was produced and showed good specificity in immunoblot testing. Cell culture was used to compare the NF-κB response after stimulation with FDL versus FDS and resulted in a significantly larger response in cells stimulated with FDL. QPCR mRNA gene expression results showed a strong innate immune response with a number of genes known to be induced downstream by the TLR signaling pathway up- regulated including important TLR5S and inflammatory cytokines and chemokines (TNFα, IL-6, IL-8, IL-1β). Microarray analysis of salmon injected with flagellin caused reproducible gene up-regulation of inflammatory cytokines, chemokines and receptors (IL-8, TNFRSF11B, IL-1R), antimicrobial peptides (hepcidin, cathelicidin), immune genes (C/EBP, thioredoxin, C-type lectin receptor B), complement genes (complement component C7 and C7-1), peptidases (MMP-9) and genes involved in the Ras/MAPK pathway (Ras-related proteins). Down-regulation of interesting immune genes also occurred including myxovirus resistance 1, clusterin-1 and LPS-induced TNF-α homolog. Some genes exhibited early, delayed or extended response over the sampling time and flagellin seemed to be the key component to eliciting a response. Flagellin was shown to induce innate immune responses in Atlantic salmon.
Description:	The papers of this thesis are not available in Munin: 1. Natasha A. Hynes, Clemens Furnes, Børge Nilsen Fredriksen, Tori Winther, Jarl Bøgwald, Atle N. Larsen, Roy A. Dalmo: 'Immune response of Atlantic salmon to recombinant flagellin', Vaccine (2011) vol. 29, no 44, pp 7678–7687. Available at http://dx.doi.org/10.1016/j.vaccine.2011.07.138 2. Natasha A. Hynes, Tiago S. Hori, Roy A. Dalmo and Matthew L. Rise: 'Functional genomics analysis of the immunological responses of Atlantic salmon (Salmo salar) spleen to injection with recombinant flagellin from Vibrio anguillarum' (manuscript)
URI:	http://hdl.handle.net/10037/3798

File(s) in this item: 1

thesis.pdf (1.079Mb)

The immune system of Atlantic cod : with emphasis on intestinal immunology

Inami, Makoto (Doctoral thesis; Doktorgradsavhandling, 08-Apr-2011)

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Abstract:	Torskeoppdrett er en lovende industri i Norge, men problemer med blant annet bakteriesykdommer gjør at næringen fortsatt har problemer med å etablere seg. For å få kontroll med sykdomsproblemene i næringen, er grunnleggende kunnskap om hvordan torsken beskytter seg mot infeksjoner nødvendig. Hensikten med dette doktorgradsarbeidet har vært å studere forsvarssystemet hos torsk, med et spesielt fokus på immunologiske celler og vev i tarmen. Arbeid i avhandlingen viser at torskens tarm er inndelt forskjellig fra for eksempel laks, noe som kan ha betydning dersom en på et senere stadium ønsker å utvikle vaksiner som kan gis til torsken via fôret. De viktigste sykdommene som har rammet torsk de seneste årene er vibriose og francisellose. Vibriose kontrolleres delvis med vaksiner, mens for francisellose er det fortsatt ingen effektive tiltak. For å vite mer om hvordan torsken responderer mot disse sykdomsfremkallende bakteriene, er genuttrykket av cytokiner og antimikrobielle peptider studert i ulike organer fra torsk i løpet av et infeksjonsforløp. Særlig ble responsen i tarmvev viet oppmerksomhet, og også i disse studiene er det vist at tarmens oppbygging er noe annerledes enn en har sett hos andre fiskearter. Også antistoffresponsen i torsk mot bakterien som forårsaker francisellose ble undersøkt, og det kom fram at levende bakterier forårsaker en mye sterkere respons i torsk enn bakterier som var inaktivert før torsken ble eksponert for dem. Resultatene fra disse studiene har gitt nye og viktige svar på hvordan torskens forsvarssystem responderer mot bakterier, og vil kunne bidra i arbeidet med hvordan en bør utvikle en vaksiner mot sykdommen francisellose. I samarbeid med Veterinærinstituttet har en i tillegg studert sykdomsinduserte forandringer, såkalt patologiske forandringer, i vev fra torsk som er smittet med francisellose, og dette har større kunnskap om sykdomstegnene som observeres hos torsk smittet med francisellose. Funnene fra studiet viser at de granuloma-lignende betennelsesområdene som er karakteristisk for sykdommen er dominert av makrofag-lignende celler, pleomorfe celler og granulocytt-like celler.
Description:	Papers 1, 2 and 4 of the thesis are not available in Munin: 1. Makoto Inami, Jan H.W.M. Rombout, Viswanath Kiron and Merete Bjørgan Schrøder: 'Immune gene expression in the initial phase of Vibrio auguillarum infection in cod (Gadus morhua L.)' (manuscript) 2. Makoto Inami, Anja J. Taverne-Thiele, Merete Bjørgan Schrøder, Viswanath Kiron and Jan H.W.M. Rombout: 'Immunological differences in intestine and rectum of Atlantic cod (Gadus morhua L.)', Fish & Shellfish Immunology (2009) 26; 751-759. (Publisher's restriction). Available at http://dx.doi.org/10.1016/j.fsi.2009.03.007 4. Makoto Inami, Sein Tore Solem, Trond Ø Jørgensen and Atle N Larsen: 'Characterization of an antiserum against Atlantic cod (Gadus morhua L.) g-type lysozyme', Fish & Shellfish Immunology (2010) 29; 1106-1109 (Publisher's restriction). Available at http://dx.doi.org/10.1016/j.fsi.2010.08.021
URI:	http://hdl.handle.net/10037/3374

File(s) in this item: 3

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Upstream vertical integration and financial performance : the case of the Norwegian fish processing industry

Isaksen, John R. (Doctoral thesis; Doktorgradsavhandling, 08-Jun-2007)

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Abstract:

In this thesis, four different articles address the correlation between vertical integration and profitability in the Norwegian fish processing industry. By vertical integration we mean the ownership and control of one firm over different stages in the value chain. Firms within this industry consider the uncertain supply of fish as a main challenge. Literature prescribes vertical integration as an organisational form that can enable industries to overcome uncertainties in raw material supply, and, hence, increase profitability. Therefore, upstream vertical integration, i.e. ownership in – and supply from own – fishing vessels or fish farms, is expected to influence profitability positively in this industry.
Detailed firm and industry data, from the period 1977–2002, reveals a great diversity of firms, with varying profitability. Also, their organisation towards the fishing fleet varies. A central conclusion from this work is that no clear correlation can be revealed between the profitability of firms and their degree of upstream vertical integration toward their raw material source.
The study also demonstrate that the key to success in this industry seem to be connected to the resources firms possess, which enables them to make the most of the advantages – and minimise the disadvantages – of their choice of strategy. While successful integrated firms utilise a continuous production and reduced transaction costs, firms without ownership in – and supply from – fishing vessels have to develop alternative relations towards the fishing fleet, and exploit the advantages from a flexible production to succeed.
A central part of the thesis has concentrated on developing adequate measures for evaluating the degree of vertical integration in firms in this industry – related to prior research and methodologies. Analyses show that in this particular industry, there exist effective and profitable alternatives which firms can utilise in order to handle the inherent uncertainty in the raw material markets.

URI:

http://hdl.handle.net/10037/2546

File(s) in this item: 6

paper_1.pdf (59.88Kb)

paper_2.pdf (245.8Kb)

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Acute and long-term effects from petroleum discharges on temperate and Arctic Calanus species

Jensen, Louise Kiel (Doctoral thesis; Doktorgradsavhandling, 11-Nov-2011)

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Abstract:	Summary Petroleum exploitation is emerging in the Arctic. In the Norwegian Arctic the southern Barents Sea is opened for development of oil and gas fields. This same area holds some of the world's largest and well managed commercial fish stocks such as Herring (Clupea harengus), Capelin (Mallotus villosus), Haddock (Melanogrammus aeglefinus), Atlantic Cod (Gadus morhua). For the interest of the fishing industry, as well as for maintaining a healthy ecosystem, petroleum related Environmental Risk Assessments (ERA) for the Barents Sea must be based on sound scientific knowledge of the special features of the Arctic ecosystem. In colder areas the physical behavior of oil is different compared to warmer areas. The lower temperature and lack of sun light during the Arctic winter slows down the natural physical weathering process of oil. In ERA in temperate areas the effects of exposure to the most volatile fraction of the oil are neglected due to short exposure time. However, in the Arctic the exposure to biota of this volatile fraction may be prolonged due to lower evaporation rates and the volatile fraction may be an important contributor to the overall adverse effect of an oil spill. Likewise, the exposure to the heavier oil fractions may be prolonged and knowledge on the long-term effects of exposure is essential. As an adaptation to the Arctic environment species found here have longer life spans, larger body sizes and higher lipid contents compared to temperate equivalent species. Thus Arctic species may accumulate contaminants over longer time and reach higher life time body levels. Meanwhile higher lipid content implies a higher affinity of lipophilic contaminants such as polycyclic aromatic hydrocarbons (PAHs). So, Arctic species may be exposed to oil compounds for a longer time because of the prolonged phycical presence and may, due to special adaptive features, be more efficient at accumulating oil contaminants. Today the knowledge of effects of oil contaminants on Arctic biota is limited, but growing. This thesis addresses a few of the research challenges in the field and provides knowledge on some effects of petroleum exposure to two copepod species; the sub-Arctic Calanus finmarchicus and the Arctic sibling species C. glacialis. First, Calanus was cultured for a generations under sub-Arctic conditions (Paper I). This work establishes that Calanus is suitable for ecological relevant long-term experiments. In an oil spill scenario, Arctic copepods and algae may be exposed to the more volatile fraction of the oil. Paper II provides data showing that the Arctic diatom species, Fragilariopsis oceanica, was the most sensitive species to exposure to the volatile hydrocarbon xylene. Further, the smaller, less lipid rich copepod species C. finmarchicus, was more sensitive compared to the true Arctic C. glacialis. Extrapolating these results to a spill situation, C. finmarchicus and C. glacialis populations would be affected by xylene exposure through both direct exposure (mortality) and indirectly through a decline in prey organisms (algae). Sub-lethal effects after long-term exposures to low concentrations of oil compounds may also be detected in C. finmarchicus and C. glacialis. Feeding was suppressed in C. finmarchicus after exposure to 7.0 µg PAHs l-1 for 11 days (Paper III). No significant effect on feeding was detected in C. glacialis exposed to 10.4 µg PAHs l-1 for 11 days. However, the hatching success of eggs laid by females exposed to 10.4 µg PAHs l-1 for two days was significantly reduced (Paper III). The long term effects of lipophilic PAHs in biota depend on the bioaccumulation capacity and internal concentrations of the various PAHs. Accumulation of lipophilic compounds is particularly important for the lipid rich Arctic species. Paper IV examines the uptake kinetics of two PAHs in C. finmarchicus and show that the accumulation of the lighter and less lipophilic compound, phenanthrene, is faster that the uptake of the heavier and more lipophilic benzo[a]pyrene (B[a]P). Equilibrium was reached for phenanthrene within 192 h exposure while no equilibrium was detected for B[a]P. The bioconcentration factor (BCF) was higher for B[a]P, reflecting the higher affinity for lipids of B[a]P compared to phenanthrene (Paper IV). So the heavier, more lipophilic PAH accumulates slower but to a higher concentration in C. finmarchicus. This thesis shows that not only acute but also long-term exposures may affect Arctic species. In addition, exposure duration may determine which compounds are accumulated by biota. Both indirect effects, such as decrease of food items, and direct effects, such as mortality, reduced feeding and reproduction failure may have implications for population development. These findings should be taken into consideration when developing ERA for the Barents Sea area.
Description:	Papers 1 and 2 of this thesis are not available in Munin: 1. Jensen, L.K., Carroll, JL., Pedersen, G., Hylland, K., Dahle, S. and Bakke, T.: 'A multigeneration Calanus finmarchicus culturing system for use in long-term oil exposure experiments', Journal of Experimental Marine Biology and Ecology (2006) 333: 71-78. Available at http://dx.doi.org/10.1016/j.jembe.2005.12.001 2. Jensen, L.K. and Carroll, JL.: 'Effects of the volatile petroleum component xylene on Arctic algae and zooplankton' (submitted manuscript to Marine Environmental Research).
URI:	http://hdl.handle.net/10037/3794

File(s) in this item: 3

paper_3.pdf (312.1Kb)

paper_4.pdf (161.7Kb)

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Key genes and regulators associated with sexual differentiation and gonad development in Atlantic cod (Gadus morhua L.)

Johnsen, Hanne (Doctoral thesis; Doktorgradsavhandling, 17-Feb-2012)

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Abstract:	Atlantic cod (Gadus morhua L.) is a promising cold-water aquaculture species, but early sexual maturation is a major problem in today’s cod farming. Teleosts display a wide variety of sex determination and sex differentiation mechanisms, ranging from genetic to environmental factors and the sexual plasticity in gonads and brain possibly reflects on a combination of these. From a practical point of view it is crucial to identify the essential biological mechanisms to develop new methods of controlling fish reproduction in aquaculture. In this thesis, several approaches were taken in order to gain basic knowledge of factors involved in sexual differentiation and gonad development in Atlantic cod. The Doublesex and mab-3 related transcription factor 1 (Dmrt1) which is involved in testis development in a wide variety of vertebrates was characterised. The dmrt gene family consists of four additional genes in cod. In order to further clarify the evolution of the dmrt gene family members in fish, the chromosomal synteny of dmrt flanking genes in different chordate lineages was examined. A novel understanding of the gene duplications of dmrts was presented as the duplicated dmrt2a and dmrt2b were probably not a result of the fish specific whole-genome duplication. Gene expression analyses during early life and the reproductive season was conducted for a selection of genes known to be involved in sexual differentiation and gonad development. The examined genes included all five dmrts, two sox9 (SRY-related high mobility group (HMG) containing box gene 9) paralogs and two cyp19a1 (cytochrome P450, family 19, subfamily A, polypeptide 1) paralogs in addition to a single anti-Müllerian hormone (amh) gene. Altogether, the different expression patterns of the examined genes in Atlantic cod embryos, larvae and adults suggest distinct functions for all the genes examined. The findings indicated that Cyp19a1a may be an important factor in female development while it was clearly demonstrated that Dmrt1 has an important role in male development of cod.
Description:	The papers of this thesis are not available in Munin: 1. Johnsen H., Seppola M., Torgersen J.S., Delghandi M., Andersen Ø.: 'Sexually dimorphic expression of dmrt1 in immature and mature Atlantic cod (Gadus morhua L.)', Comparative Biochemistry and Physiology, Part B Biochemistry and Molecular Biology (2010) 156; 197-205. Available at http://dx.doi.org/10.1016/j.cbpb.2010.03.009 2. Johnsen H., Andersen Ø.: 'Differential expression of five dmrt genes identified in the Atlantic cod genome. The fish-specific dmrt2b diverged from dmrt2a before the fish whole-genome duplication' (accepted manuscript in Gene). 3. Johnsen H., Tveiten H., Torgersen J.S., Andersen Ø.: 'Sexually dimorphic expression of amh and paralogs of sox9 and cyp19a in Atlantic cod (Gadus morhua L.)' (manuscript prepared for submission to Molecular Reproduction and Development).
URI:	http://hdl.handle.net/10037/4117

File(s) in this item: 1

thesis.pdf (1.483Mb)

Fiskeren som forsvant? En studie av avfolking, overbefolking og endringsprosesser i norsk fiskerinæring

Johnsen, Jahn Petter (Doctoral thesis; Doktorgradsavhandling, 28-Feb-2003)

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Abstract:

Hva er en fisker? Dette er det sentrale spørsmålet i denne avhandlinga. Spørsmålet er utgangspunkt for å utforske endringsprosesser i fiskerinæringa, både i fortida og i samtida. På bakgrunn av dette drøfter avhandlinga hvilke oppfatninger, forståelser og beskrivelser som til enhver tid benyttes til å definere hva fiskere er i ulike sammenhenger. Undersøkelsen starter i det som kan kalles rekrutteringsdiskursen i fiske, som nettopp handler om hva fiskere er og hvordan de skapes. Avhandlinga fokuserer på hvilke forståelser av fiskeren som formidles i denne diskursen, og identifiserer både hvor oppfatningene kommer fra og hvordan de brukes som strategier og repertoarer for å forme fiskerinæringa. I denne avhandlinga betraktes fiskeren som en heterogen skapning som forandrer karakter og vesen alt etter hvilke heterogene forbindelser den inngår i. I stedet for substansialistiske forklaringer og analyser som henter sin forståelse i at fiskeren er noe gitt og substansielt som klart kan defineres uttømmende og en gang for alle, bygger dette arbeidet på relasjonistiske tilnærminger som følger i kjølvatnet av den postmoderne kritikken innen samfunnsvitenskapene. Med aktør-nettverk-teori som teoretisk rammeverk og ei kvalitativ tilnærming til vitenskapelige tekster, intervjuer, rapporter, statistikk og filmmateriale, undersøkes det hvordan fiskeren formes gjennom det vi kan kalle moderniseringsmaskineriet. Avhandlinga beskriver hvordan vitenskapelige, politiske, tekniske og økonomiske ressurser, mobiliseres og knyttes sammen for å modernisere fiskerinæringa. Moderniseringsprosessene har tatt utgangspunkt i tre forskjellige oppfatninger av hva fiskeren er: Fiskeren har blitt betrakta enten som en individualistisk, rasjonell aktør: som i dette arbeidet kalles Den rasjonelle fiskeren, som en strukturalistisk, verdensskapt aktør: Verden i fiskeren eller som en aktør som skapes i et gjensidig møte mellom individ og verden: Fiskeren i verden. Avhandlinga beskriver hvordan disse tre oppfatningene, som er oversettelser av filosofiske teorier om mennesket, har vært utgangspunkt for vitenskapelige og politiske analyser i fiskerinæringa. Avhandlinga beskriver hvordan oppfatningene har blitt benytta til å integrere fiskerinæringa i det moderne samfunnet og hva som har blitt konsekvensen av prosessene i forhold til spørsmålet om rekruttering og bemanning. Hovedkonklusjonen er at samtidig som fiskerinæringa er opptatt av et avfolkingsproblem, der fiskeren som et menneske forsvinner, foregår det også ei kontinuerlig overbefolking av fiskerinæringa, ikke først og fremst i form av mennesker, men av hybride forbindelser som gir grunnlag for en ny definisjon og forståelse av hva en fisker er.

URI:

http://hdl.handle.net/10037/1154

File(s) in this item: 1

thesis.pdf (1.911Mb)

The effects of behaviour on the acoustic target strength of capelin (Mallotus villosus) and implications for acoustic abundance estimation

Jørgensen, Roar (Doctoral thesis; Doktorgradsavhandling, 2004)

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Abstract:	The general objective of this thesis was to collect improved knowledge about the target strength (TS) of capelin (Mallotus villosus) through experimental studies, as well as to undertake adequate observations of behaviour of capelin during surveying situations, including the effect of different depth distributions and of vessel avoidance. Pre- and post-spawning capelin from the Balsfjord and the Barents Sea stock were observed in a net pen and in a submersible rig with a calibrated 38-kHz scientific splitbeam echo sounder. The net pen experiment showed that the acoustic TS of capelin depended on swimbladder length. In females, TS tended to be negatively influenced by condition. The experiments in the submersible rig demonstrated that the TS of capelin depends on the tilt-angle distribution and ambient pressure. The avoidance reactions of Barents Sea capelin to Norwegian research vessels were studied by means of the Bergen Acoustic Buoy (BAB), which was equipped with a 38 kHz echo sounder. BAB experiments were carried out in the capelin’s feeding area in the Barents Sea in the autumn, and on its spawning grounds in Varangerfjord in North Norway in early spring. There was no significant influence of the avoidance reactions of capelin to survey vessels on the volume scattering coefficient, either in the feeding area or on the spawning grounds. However, there were indications of changes in the centre of depth distribution (diving) before the pass, especially in dense concentrations on the spawning grounds. The findings of this thesis indicate that differences in vertical distribution of capelin in different areas and seasons, or between years with differences in oceanographic conditions or predation, may bias absolute estimates of stock abundance of capelin if the depth distribution of the fish is not taken into consideration. It is therefore recommended that the effects of ambient pressure are included in the TS equation used in surveys in order to make the acoustic stock size estimate of capelin in the Barents Sea a better absolute estimate of the stock abundance.
Description:	Papers 1-3 of this thesis are not available in Munin: 1. Jørgensen, R., and K.K. Olsen.: 'Acoustic target strength of capelin measured by single-target tracking in a controlled cage experiment', ICES Journal of Marine Science 59: 1081-1085. Available at http://dx.doi.org/10.1006/jmsc.2002.1239 2. Jørgensen, R.: 'The effects of swimbladder size, condition and gonads on the acoustic target strength of mature capelin', ICES Journal of Marine Science (2003), 60:1056-1062. Available at http://dx.doi.org/10.1016/S1054-3139(03)00115-2 3. Jørgensen, R., N.O. Handegard, H. Gjøsæter, and A. Slotte: 'Possible vessel avoidance behaviour of capelin in a feeding area and on a spawning ground', Fisheries Research (2004), 69:252-261. Available at http://dx.doi.org/10.1016/j.fishres.2004.04.012
URI:	http://hdl.handle.net/10037/4115

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