Munin: Browsing Doktorgradsavhandlinger (BFE-fak) by Title

Risk sensitive reproductive strategies : the effect of environmental unpredictability

Bårdsen, Bård-Jørgen (Doctoral thesis; Doktorgradsavhandling, 13-Feb-2009)

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Abstract:	A crucial task in ecology is to quantify trade offs between competing demographic processes for experienced by individuals that inhabit unpredictable environments. Perhaps the most widely studied trade off is that between current reproduction and future survival (‘the cost of reproduction’). While experimental studies have been widely used to quantify life history strategies in birds, virtually no experimental studies have been carried out on large and free ranging mammals. This thesis quantifies how female reindeer Rangifer tarandus subject to variability in food availability, trade their resources between reproduction and body mass to ensure own survival. By combining two experiments, one observational study and one theoretical model, this thesis show that: (1) Individuals subject to reduced food availability in one winter feeding promptly reduced their reproductive allocation the following summer to increased their autumn body mass. On the other hand, short-term improved conditions did not result in increased reproductive allocation. (2) Long-term improved winter feeding conditions did, however, result in increased reproductive allocation. (3) Reproduction was costly, especially for smaller females, as occasional harsh winters and high population density resulted in reduced reproduction and lowered female body mass. Moreover, a successfully reproducing female produced a smaller offspring in the coming year relative to a barren one. Reindeer also differ in their intrinsic quality as successfully reproducing females’ showed an increased probability of reproducing also in the following year. (4) In harsh and unpredictable winter conditions, the optimal reproductive strategy involved a low reproductive allocation per unit female spring body mass. Under such conditions females increased their autumn body mass to enhance their own survival. Conversely, the optimal reproductive strategy in benign and predictable conditions involved a higher reproductive allocation. (5) Reproductive strategies and environmental conditions had significant effects on population dynamics. Female reindeer do not to jeopardize their own survival and adjust their reproductive allocation in order to buffer periods of low food availability in a risk sensitive manner.
Description:	Papers number 1 and 2 of the thesis are not available in Munin, due to publishers' restrictions: 1. Bårdsen, B.-J., P. Fauchald, T. Tveraa, K. Langeland, N. G. Yoccoz, and R. A. Ims: "Experimental evidence for a risk sensitive reproductive allocation in a long-lived mammal", Ecology (2008)89:829-837 (Ecological Society of America). Available at http://dx.doi.org/10.1890/07-0414.1 2. Bårdsen, B.-J., P. Fauchald, T. Tveraa, K. Langeland, and M. Nieminen: "Experimental evidence of cost of lactation in a low risk environment for a long-lived mammal", Oikos (2009)118:837-852. Available at http://dx.doi.org/10.1111/j.1600-0706.2008.17414.x
URI:	http://hdl.handle.net/10037/2807

File(s) in this item: 3

paper_3.pdf (1.666Mb)

paper_4.pdf (2.045Mb)

thesis.pdf (1.924Mb)

Scavenging amphipods in the high Arctic : Studies of benthic and sympagic amphipods in the genera Onisimus and Anonyx

Nygård, Henrik (Doctoral thesis; Doktorgradsavhandling, 02-May-2011)

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Abstract:	The main objective of this study was to increase our knowledge about the ecology of scavenging amphipods, particularly amphipods within the genera Onisimus and Anonyx. Specifically, the emphasis was to increase the knowledge of ice-associated (sympagic) Onisimus-species, but as these species are rather inaccessible, an approach using benthic congeners as proxies was chosen. By studying the shallow-water scavenging amphipods, a high temporal resolution in sampling could be achieved, resulting in detailed descriptions of life cycles and reproduction parameters of Onisimus caricus and O. litoralis. As seasonal studies on the amphipod scavenging guilds in the Arctic are rare, this study also includes a description of the seasonal variations in the amphipod scavenging guild in two fjords in Svalbard, Norway. Feeding strategies of the scavenging amphipods were studied using fatty acid composition and stable isotopes. Extrapolating the knowledge gained on benthic Onisimus-species to sympagic congeners showed that O. nanseni likely follows a similar life strategy as O. litoralis, being an income breeder. Additionally, the extended parental care by investing in a “start pack” of energy to the offspring is likely similar in these two species. Further, it could be hypothesized that O. nanseni and O. glacialis need a higher reproductive output in order to compensate for the high variation in the extent and loss of their sea ice habitat. However, further studies are needed to confirm this. A first step would be to obtain good winter samples, containing ovigerous females of O. nanseni and O. glacialis, that could give information on reproduction parameters and thus illuminate their life strategies and adaptations towards the sea ice habitat.
Description:	The papers of the thesis are not available in Munin: 1. Henrik Nygård, Mikko Vihtakari and Jørgen Berge:'Life history of Onisimus caricus (Amphipoda: Lysianassoidea) in a high Arctic fjord', Aquatic Biology (2009) 5:63-74. (Publisher's restriction). Available at http://dx.doi.org/10.3354/ab00142 2. Henrik Nygård, Jago Wallenschus, Lionel Camus, Øystein Varpe and Jørgen Berge:'Annual routines and life history of the amphipod Onisimus litoralis: seasonal growth, body composition and energy budget',Marine Ecology Progress Series (2010) 417:115-126. (Publisher's restriction) Available at http//dx.doi.org/10.3354/meps08798 3. Marek Zajączkowski, Henrik Nygård, Else Nøst Hegseth and Jørgen Berge:'Vertical flux of particulate matter in an Arctic fjord: the case of lack of the sea-ice cover in Adventfjorden 2006-2007',Polar Biology (2010), 33:223-239. (Publisher's restriction). Available at http://dx.doi.org/10.1007/s00300-009-0699-x 4. Henrik Nygård, Jørgen Berge, Janne E. Søreide, Mikko Vihtakari and Stig Falk-Petersen:'The amphipod scavenging guild in two Arctic fjords: seasonal variations, abundance and trophic interactions' (manuscript). 5. Henrik Nygård, Jørgen Berge, Bjørn Gulliksen and Lionel Camus:'The occurrence of Eualus gaimardii gibba Krøyer 1841 (Crustacea, Decapoda) in the sympagic habitat: an example of bentho-sympagic coupling', Polar Biology (2007) 30:1351-1354. (Publisher's restriction). Available at http://dx.doi.org/10.1007/s00300-007-0302-2
URI:	http://hdl.handle.net/10037/3382

File(s) in this item: 1

thesis.pdf (899.1Kb)

Seabirds, climate and prey. A population study of two seabird species.

Reiertsen, Tone Kristin (Doctoral thesis; Doktorgradsavhandling, 30-May-2013)

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Abstract:	Many seabird populations have declined dramatically over recent decades, and studying the demography and population dynamic in seabird populations is important to gaining a better understanding of causes and mechanisms lying behind such changes and to identify targets for conservation and management. Climate and prey availability are known to affect demography and population dynamics of seabirds. Climate is now changing and a warming of the ocean may lead to changed availability of prey species and will affect seabirds through their demographic traits and ultimately their abundance and distribution. The main aim of this thesis was to study the impact of climate and prey abundance on seabird demography and population dynamics, using two seabird populations; the black-legged kittiwake Rissa tridactyla and the Common guillemot Uria aalge breeding on Hornøya in NE Norway whose populations are declining in Norway. The first question addressed in the thesis was how environmental conditions affect the demography and population variability of kittiwakes and guillemots. The non-breeding distribution of the kittiwakes has recently been documented using year-round light-based geolocators, and we investigated the relationship between environmental conditions in these non-breeding areas and the adult survival of kittiwakes breeding on Hornøya. We found for the kittiwakes that Thecosomata, a group of pteropods (also called sea butterflies), in the Grand Banks/Labrador Sea area in winter and the capelin Mallotus villosus stock in Barents Sea in the pre-breeding season together explained as much as 52 % of the yearly variation in adult survival rate. Further we found that the availability of 0-group cod Gadus morhua was a much more important factor affecting demography and determining the population dynamics of the common guillemot in the Barents Sea than previously considered. The second question was which demographic trait drives the population dynamics of the steeply declining kittiwake population on Hornøya. We showed, by using demographic matrix modeling and LTRE analyses, that both the variability in breeding success (and hence the recruitment to the population) and adult survival rate contributed to the steep decline in the kittiwake population on Hornøya. The strong reduction in breeding success (and hence a decline in recruitment to the population) had, however, the highest impact. The final question was whether populations can adapt to environmental changes through micro-evolutionary processes. This study found that adult survival of the two different genetic colour morphs (bridled and non-bridled morph) of the common guillemot responded differently to yearly variability in sea surface temperatures. Colour dimorphism may, in this case serve as a genetic marker in the guillemot population, and can potentially visualize the direction of selection and micro-evolutionary processes driven by climate. The studies in this thesis contribute to the understanding of the population dynamic of two declining seabird species which are both on the Norwegian Red List, and to the directions of future studies and conservation targets of both species.
Description:	Papers 1, 2 and 4 of this thesis are not available in Munin: 1. Reiertsen, T.K., Erikstad, K.E., Anker-Nilssen, T., Barrett, R.T., Boulinier, T., Frederiksen, M., González-Solís, J., Gremillet, D., Johns, D., Moe, B., Ponchon, A., Sandvik, H., Skern-Mauritzen, M. and Yoccoz, N.G.: 'Prey density in non-breeding areas affects adult survival of black-legged kittiwakes Rissa tridactyla breeding in the southern Barents Sea' (manuscript). 2. Reiertsen, T.K., Barrett, R.T. and Erikstad, K.E.: 'Kittiwakes on the cliff edge: a demographic analysis of a steeply declining arctic kittiwake population' (manuscript). 4. Reiertsen, T.K., Erikstad, K.., Barrett, R.obert T., Sandvik, H. and Yoccoz, N.: 'Climate fluctuations and differential survival of bridled and non-bridled Common Guillemots Uria aalge', Ecosphere (2013), vol. 3(6). Available at http://dx.doi.org/10.1890/ES12-00031R
URI:	http://hdl.handle.net/10037/5158

File(s) in this item: 2

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Species concepts and functional aspects of cold-water diatoms (Bacillariophyceae)

Degerlund, Maria (Doctoral thesis; Doktorgradsavhandling, 18-Oct-2011)

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Abstract:	The choice of species concept when delineating phytoplankton species is decisive for our knowledge of species diversity and distribution, but will also affect our understanding of the functioning of marine ecosystems. This is particularly true for so-called cryptic species, which may show high degree of genetic and physiological heterogeneity although being morphologically similar. A precise species delimitation procedure appreciating the value of genotypic as well as phenotypic traits is therefore important. In this thesis, species concepts and functional aspects in abundant cold-water diatoms were investigated using biogeographic (species presence and abundance), taxonomic (morphological and molecular data), and functional (experimental physiological and metabolomics data) tools. A compilation of multiannual phytoplankton species abundance data gathered during the spring bloom period from north-east Atlantic and Arctic waters (68-80oN) revealed high similarities in associations of the most abundant species. Spring associations were dominated by the diatom Chaetoceros socialis and the prymnesiophyte Phaeocystis pouchetii. A corresponding investigation of the winter period in this area could not identify associations of actively growing, autotrophic phytoplankton species. Change in species composition and abundance in time could not be assessed due to lack of consistency and regularity in sampling. A high-resolution time series of phytoplankton distribution is therefore needed in this area. A case study of the so-called cosmopolitan diatom C. socialis was performed using strains from north-east Atlantic/Arctic and from Mediterranean waters. By applying a phylo-phenetic species concept the two geographical populations were found to be pseudo-cryptic. They were genetically distinct, but only slight morphological differences were observed, in this case in resting spore morphology. Furthermore, when cultivated at 2.5, 8 and 13oC, the two groups of strains were functionally different in terms of growth rates (doublings day-1), photosynthetic efficiency (maximum quantum yield), and metabolic profiles. Our results do not support the assumed cosmopolitan distribution of C. socialis and therefore the present taxonomy of this species will need revision. A taxonomic update of the pseudo-cryptic diatom formerly known as Skeletonema costatum indicated that the species present in northern Norwegian and Barents Sea waters is identical to S. marinoi. Due to reports of high genetic, metabolic, and physiological diversity within this species, a functional approach would be valuable for understanding the ecology of S. marinoi in this area. Integrated approaches combining taxonomic and functional variables are recommended for future taxonomic work on phytoplankton species. Similarly, phytoplankton ecologists are urged to acknowledge the high degree of hidden taxonomic and functional diversity present in several phytoplankton species. Functional diversity studies are suggested to be a useful spot for integration and eventual modelling phenotypic, genotypic and ecological species data. Ultimately, such an approach should be beneficial also at the ecosystem level.
Description:	The papers of this thesis are not available in Munin: 1. Degerlund M and Eilertsen HC: 'Main species characteristics of phytoplankton spring blooms in NE Atlantic and Arctic waters(68–80°N)', Estuaries and Coasts (2010) 33: 242-269. Available at http://dx.doi.org/10.1007/s12237-009-9167-7 2. Eilertsen HC and Degerlund M: 'Phytoplankton and light during the northern high-latitude winter', Journal of Plankton Research (2010) 32: 899-912. Available at http://dx.doi.org/10.1093/plankt/fbq017 3. Degerlund M, Huseby S, Zingone A, Sarno D and Landfald B: 'Functional diversity in cryptic species of Chaetoceros socialis Lauder (Bacillariophyceae)' (submitted paper to Journal of Plankton Research). 4. Huseby S, Degerlund M, Zingone A and Hansen, E: 'Metabolite fingerprinting and physiology of the cryptic diatom Chaetoceros socialis Lauder' (manuscript)
URI:	http://hdl.handle.net/10037/3679

File(s) in this item: 1

thesis.pdf (1.139Mb)

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

File(s) in this item: 1

thesis.pdf (6.563Mb)

Stoichiometry of lipid synthesizing calanoid copepods in Arctic and sub-Arctic marine regions Insights into limitation and elemental cycling from characterization of C:N:P ratios

Aubert, Anaïs (Doctoral thesis; Doktorgradsavhandling, 12-Dec-2012)

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Abstract:	Calanoid copepods, Calanus finmarchicus, C. glacialis and C. hyperboreus, are key species in Arctic and sub-Arctic marine ecosystems. They represent important prey for a number of species such as juvenile herring and cod because of their high but seasonally variable calorific value: they synthesize and store lipids as part of their survival strategy. Limitations in food quantity and quality can have strong impact on the copepods’ lipid synthesis and development, with implications for their predators and thus for the lipid-driven Arctic marine food web. Ecological stoichiometry, i.e. the study of the relative abundance of elements (most commonly carbon, nitrogen, and phosphorus) in biological entities, is a powerful tool to study potential limitation of aquatic organisms, particularly in primary producers and in omnivorous and herbivorous zooplankton grazers. However, studies that apply a stoichiometric approach to the high-latitude marine regions are extremely rare. The main aim of this thesis is to reveal the elemental requirements and potential limitation of high-latitude calanoid copepods by investigating their C:N:P composition in combination with information on other biochemical compounds. The impact of copepods on nutrient recycling and C:N:P export through fecal pellets is also investigated. The study was conducted in a sub-Arctic north-Norwegian fjord, and in the western part of the European Arctic Ocean, focusing on the period of intense primary production during spring. Somatic stoichiometric ratios in copepods were calculated by subtracting C in the lipid sac from the total body C. Due to the strong influence of lipid storage on total body stoichiometry, high-latitude calanoid copepods, and by implication lipid-synthesizing zooplankton in general, should be treated through a two-compartment stoichiometric approach, with lipid storage and somatic tissues separated. Both season and development stage influence the somatic elemental ratios. The somatic C:P ratios of high-latitude calanoid copepods are somewhat lower than those reported in marine copepods from other areas, suggesting that they have higher growth rates than temperate and tropical copepods. Seston C:N:P stoichiometry is used as a proxy for food quality in the calculation of copepod elemental limitation. The seston C:P and N:P ratios are among the first to be reported for the Arctic Ocean and indicate a higher relative proportion of nutrients (N and P) compared to published seston values from other marine regions. Seston C:N:P ratios varied according to bloom stage, which therefore also impacts the potential C, N or P limitation of copepods. Unless they have high assimilation efficiency for C, calanoid copepods are shown to be most likely subject to C limitation. However, variable requirements during ontogeny make specific stages, such as copepodite IV, and females more sensitive to nutrient limitation (N or P). This study is the first to present data on stoichiometric ratios including P for copepod fecal pellets in the Arctic, and shows their high potential not only to vertically export P at depth but also to provide a source of P in the upper layers during the productive season if degraded. The Arctic marine regions are experiencing the greatest climate change, and the potential future stoichiometric changes in the Arctic and how climate change affects copepod-seston interaction are discussed.
Description:	The papers of this thesis are not available in Munin: 1. Aubert, A.B., Svensen, C., Hessen, D., Tamelander, T.: 'CNP stoichiometry of a lipid-synthesising calanoid copepod, Calanus finmarchicus, from winter to spring bloom in a sub-Arctic sound', Journal of Marine Systems (2012), Volumes 111–112, pp.19–28. Available at http://dx.doi.org/10.1016/j.jmarsys.2012.09.004 2. Aubert, A.B., Tamelander, T.: 'Stoichiometric approach to elemental limitation of pelagic producers and grazers during the Arctic summer' (manuscript). 3. Tamelander, T., Aubert, A. B., Wexels Riser, C.: 'Export stoichiometry and contribution of copepod faecal pellets to vertical flux of particulate carbon, nitrogen and phosphorus', Marine Ecology Progress Series (2012), vol.459, pp.17-28. Available at http://dx.doi.org/10.3354/meps09733
URI:	http://hdl.handle.net/10037/4768

File(s) in this item: 1

thesis.pdf (1.905Mb)

Studies of infectious pancreatic necrosis virus (IPNV) and immune evasion strategies

Skjesol, Astrid (Doctoral thesis; Doktorgradsavhandling, 23-Oct-2009)

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Abstract:	Infectious pancreatic necrosis (IPN) is a highly contagious disease which causes huge economic loss to the salmon farming industry world wide. The causative agent, the IPN virus (IPNV), is a dsRNA, non-enveloped virus with two genomic segments encoding five viral proteins, VP1-VP5. Available vaccines against this disease give only partial protection. In order to optimize vaccine efficacies, properties of the virus and virus-host interactions during an infection need to be elucidated. In this thesis, interactions between the individual viral proteins are described and functional analyses of the interactions performed. VP3 was found to be a key organizer in the viral particle, as it binds both to other VP3 proteins, to the VP1 RNA-dependent RNA-polymerase and to the viral genome. The different binding domains were mapped. Elucidation of fish defense against virus infections is also essential. Interferons (IFNs) act as “alarm” proteins and are produced upon viral infections. Most viruses have evolved strategies to avoid host defense. This is also true for IPNV. Treatment of uninfected cells with IFN makes the cells resistant to IPNV infection, whereas addition of IFN after the onset of viral replication enables the IPN virus to overcome host defense, and reduce the antiviral activity. Thus, IPNV has an antagonistic effect on the IFN-signaling pathway (JAK/STAT pathway). We suggest the viral proteins VP4 and VP5 to be implicated in this effect. STAT1 is a central molecule that is being activated by IFN and participates in up-regulation of antiviral genes. In this work STAT1 from Atlantic salmon has been cloned and found to have properties similar to mammalian STAT1; salmon STAT1 was activated by phosphorylation and translocated from cytoplasm to the nucleus upon stimulation with IFNs.
Description:	Papers number 1 and 2 of the thesis are not available in Munin due to publishers' restrictions: 1. Torunn Pedersen, Astrid Skjesol and Jorunn B. Jørgensen: «VP3, a structural protein of the infectious pancreatic necrosis virus, interacts with the RNA-dependent RNA polymerase VP1 and with double-stranded RNA», Journal of virology; 2007, 81(12), 6652-6663 (American Society for Microbiology). Available at http://dx.doi.org/10.1128/JVI.02831-06 2. Astrid Skjesol, Toril Aamo, Marit Nøst Hegseth, Børre Robertsen and Jorunn B. Jørgensen: «The interplay between infectious pancreatic necrosis virus (IPNV) and the IFN system: IFN signaling is inhibited by IPNV infection», Virus Research; 2009, 143, 53-60 (Elsevier). Available at http://dx.doi.org/10.1016/j.virusres.2009.03.004
URI:	http://hdl.handle.net/10037/2589

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paper_3.pdf (4.055Mb)

thesis.pdf (1.078Mb)

Studies on the amphipod genus Metopa (Stenothoidae) : Taxonomy, Ecology, Phylogeny

Tandberg, Anne Helene S. (Doctoral thesis; Doktorgradsavhandling, 19-Dec-2011)

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Abstract:	The Amphipod-genus Metopa is a relatively large genus, with currently 55 accepted species. This PhD thesis consists of redescriptions of 23 of these species based on typespecimens or specimens collected and identified by the original authors; this has been done to create consistent descriptions that could form a basis for a phylogenetic analysis of Metopa. For some species Scanning Electron Microscopy has been used to look for characters that have been overlooked by the original authors. The redescriptions are presented in 3 papers (Papers 1-3), with a phylogenetic analysis of 37 Metopa species (mostly based on personal examinations, but 6 based on literature-information) together with 6 Stenula species (partly based on literature, but most from examinations performed by Dr. Traudl Krapp-Schickel) presented in a manuscript (Paper 6). The result of the phylogenetic analysis is two clear clades (A and B), both including species from both original genera. This result could suggest a thorough change in stenothoid systematics, with the possible synonymization of Stenula into the older Metopa and erection of one or more new genera to include the species of clade A, but we have argued against doing this before further investigations have been undertaken. The stability of the resulting phylogeny is discussed, and in our opinion further studies are necessary to strengthen the conclusions reached here, before we formally make the necessarily very extensive nomenclatorial changes. However, the indications that Metopa and Stenula are paraphyletic are strong. Two papers (Papers 4-5) examine the ecology of Metopa species associated with mollusks. Paper 4 is a short note about findings of Metopa alderii inside the mussel Musculus spp., whereas Paper 5 is a more thorough discussion on the possible life history strategies for Metopa glacialis in its well known association with the mussel Musculus discors based on data collected by Svalbard. We show the presence of more than one broods in several examined mussels, and from the brood sizes and cohort compositions we suggest two possible scenarios: 3 or more seasons of single broods and parental care over more than 1 year after hatching, or multiple broods in one season and extended parental care. The introductory synthesis to the papers gives a short discussion of the papers, in addition to a historical introduction to both taxonomy and the amphipod-genus Metopa. A complete list of taxa that at some time have been included in Metopa is presented, this includes synonymies and references to the auctors and different authors who have moved the different taxa. There is also a table with biogeographical information about the genus, and the ecology of Metopa is discussed. A short discussion on molecular methods and the possible ways to ensure more data for a better phylogenetic analysis is also included.
Description:	The papers of this thesis are not available in Munin. 1. Tandberg, A.H.S. and Vader, W.: 'A redescription of Metopa species (Amphipoda, Stenothoidae) based on the type material. 1. Zoological Museum, Copenhagen (ZMUC)', Zootaxa (2009) 2093:1-36. Available at http://www.mapress.com/zootaxa/ 2. Tandberg, A.H.S.: 'A redescription of Metopa species (Amphipoda, Stenothoidae) based on the type material. 2. The United States National Museum of Natural History (NMNH)', Zootaxa (2009) 2309:43-68. Available at http://www.mapress.com/zootaxa/ 3. Tandberg, A.H.S.: 'A redescription of Metopa species (Amphipoda, Stenothoidae) based on the type material. 2. The Natural History Museum Oslo (NHM)', Zootaxa (2010) 2465:1-94. Available at http://www.mapress.com/zootaxa/ 4. Tandberg, A.H.S., Schander, C. and Pleijel, F.: 'First record of the association between the amphipod Metopa alderii and the bivalve Musculus', Marine Biodiversity Records (2010) 3, e5. Available at http://dx.doi.org/10.1017/S1755267209991102 5. Tandberg, A.H.S., Vader, W. and Berge, J.: 'Metopa glacialis : an analysis of its ecology and its association with Musculus discors', Polar Biology (2010) 33:1407-1418. Available at http://dx.doi.org/10.1007/s00300-010-0833-9 6. Tandberg, A.H.S. and Vader, W.: 'Phylogenetic analysis of the stenothoid genera Metopa and Stenula (Crustacea, Amphipoda, Stenothoidae)' (manuscript)
URI:	http://hdl.handle.net/10037/3808

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thesis.pdf (35.46Mb)

Technology transfer and R&D policy in a knowledge-based society

Michalsen, Anita (Doctoral thesis; Doktorgradsavhandling, 01-Jun-2012)

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Abstract:	Abstract My thesis focuses on technology transfer and innovation policy in a knowledge-based society. In particular, I analyse the firms’ incentives to invest in research and development (R&D), the transfer of technological knowledge to a rival and government stimulation of R&D investment. Further, I analyse the incentives to engage in R&D cooperation in different market structures. By coordinating R&D decisions the firms can internalize the externalities of their research effort, and thereby strengthen the incentives to perform R&D. The dissertation consists of three essays where I develop theoretical models within the subject of strategic R&D investment. As a consequence of externalities that arise when conducting R&D, the economic value to society often exceeds the economic benefits enjoyed by the innovating firms. Since the output of R&D investments is non-rival and only partially excludable, some of the knowledge also benefits their competitors and thereby reduces the incentive to engage in R&D activities. By coordinating these R&D activities the firms can internalize this externality. Knowledge created by one firm is typically not contained within that firm, and R&D spillovers occur when technological knowledge produced by one firm is transferred to other firms, both voluntarily and involuntarily. In my first paper I study how separation of ownership and management affects firms’ incentives to transfer technological knowledge voluntarily and without payment from a rival in a Cournot duopoly. The main finding is that strategic management does not necessarily increase the incentives to transfer technology, but it can change the adoption of technologies. In my next paper I study the effectiveness of public funding aimed at stimulating business performed R&D in a vertically related market. In particular, the focus of the analysis is how to set the policy instruments upstream and downstream in order to achieve an optimal level of innovation in the whole industry. I show that it is always optimal to subsidize the R&D activity of the upstream firm. Whether a tax or a subsidy is used in the downstream market depends upon its level of concentration. If there are few firms downstream, then it is always optimal to employ an R&D subsidy in this part of the market. However, if competition is sufficiently strong, then R&D activity downstream should be taxed. The optimal R&D policy implies a differentiation of the subsidy rates between the upstream and the downstream market. Moreover, subsidizing the upstream supplier has a greater effect on welfare than the stimulation of each of the downstream buyers. In my third paper I study strategic R&D alliances among asymmetric firms. I consider a market where some of the firms are active in research, while other firms do not conduct R&D. With non-innovative firms as technologically leading firms, the innovating firms invest in R&D to narrow the technological gap. On the other hand, with the technologically leading firms investing in R&D they expand their technological advantage. In the analysis I determine whether R&D cooperation leads to higher levels of R&D than R&D competition under different market structures. Cost asymmetries among firms seems to enlarge the interval of spillover rates where cooperative R&D secures greater R&D effort than competitive behaviour, and this depends on the number of firms that do not perform R&D or the number of firms that do not receive R&D spillover.
Description:	The papers of this thesis are not available in Munin: 1. Clark, D. J., and Michalsen, A.: 'Managerial Incentives for Technology Transfer', Economics of Innovation and New Technology (2010), vol.19, no.7:649-668. Available at http://dx.doi.org/10.1080/10438590903128974 2. Michalsen, A.: 'R&D Policy in a Vertically Related Industry' (forthcomming paper in Economics of Innovation and New Technology). 3. Michalsen, A.: 'R&D Cooperation and Market Structure' (manuscript)
URI:	http://hdl.handle.net/10037/4270

File(s) in this item: 1

thesis.pdf (801.6Kb)

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

File(s) in this item: 2

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The governance of Sami reindeer husbandry in Norway : institutional challenges of co-management

Ulvevadet, Birgitte (Doctoral thesis; Doktorgradsavhandling, 15-Jun-2012)

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Abstract:	Denne avhandlingen er basert på en kvalitativ studie fra forvaltningen av reindriften i Norge. Målet med forvaltningen av reindriften i Norge er å oppnå en økologisk, økonomisk, og kulturell bærekraftig reindrift. Disse målene har blitt forsøkt oppnådd gjennom et governance system fordi myndighetene har erkjent at det å inkludere ressursbrukere i forvaltningsmessige beslutningsprosesser skaper en mer rettmessig forvaltningspolitikk. For å øke medvirkningen for ressursbrukere har norske myndigheter iverksatt to ulike forvaltningsmodeller i den samiske reindriften. På den ene siden er det innført et korporativt system hvor utvalgte reineiere representerer reindriften i de årlige forhandlingene med myndighetene. I disse forhandlingene blir det økonomiske grunnlaget for reindriften lagt gjennom ulike subsidieordninger. På den andre siden er det iverksatt et medforvaltningssystem hvor reineiere er representert i styrer på lokalt, regionalt og nasjonalt nivå. Staten har også delegert en del forvaltningsgjøremål til disse styrene. Medforvaltningssystemet utgjør fire nivåer; de to øverste nivåene består av styremedlemmer (både reineiere og andre) som er politisk valgt og dermed tar politiske beslutninger. De to lavere nivåene, på det lokale plan, har kun reineiere som styremedlemmer. Det har vært vanskelig for myndighetene å få et så stort og komplekst forvaltningssystem til å fungere slik det var planlagt og det har vært utfordringer på flere hold. Det er mange grupper som skal være med i forvaltningen, både reindriftssamer og representanter fra andre næringer som har interesser i de samme områdene som reineierne bruker. I denne prosessen har noen grupper fått mer makt enn andre og dette har satt sitt preg på forvaltningssystemet. I styrer, for eksempel, så ser man at noen grupper ender opp i mindretall og på den måten alltid ”taper” sine saker. Reindriftens næringsorganisasjon, Norges Reindriftssamers landsforbund (NRL), har fått en relativt sterk posisjon i forvaltningen av reindriftsnæringen. NRL har både monopol på forhandlingsrett med staten i det korporative systemet og i tillegg har NRL en lovfestet rett til å foreslå kandidater til medforvaltningsstyrene, som blir formelt oppnevnt av Fylkestinget, Sametinget og Landbruks- og matdepartementet (LMD). I loven står det at NRLs forlag til kandidater bør følges så langt dette er mulig. Naturlig nok så foreslår NRL alltid egne medlemmer. På den måten så er NRL (sentralt) med på å utforme subsidiesystemet for reindriftsnæringen og NRL medlemmer er med på å forme og implementere politikk gjennom medforvaltningsstyrene. For NRL medlemmer er dette positivt, for en del ikke-medlemmer så er ikke dette like populært. Subsidiesystemet har vært forhandlet frem mellom LMD og NRL i over 30 år. Målet med subsidiesystemet har vært å oppnå en økologisk, økonomisk og kulturell bærekraftig reindrift. For Finnmarks vedkommende, som sliter med et for høyt reintall, så har subsidiesystemet ment å kompensere økonomisk for en reduksjon i reintallet. Mye av reindriftspolitikken dreier seg om Finnmark, men 75% av reindriften i Norge drives også i Finnmak. I store deler av Finnmark har subsidiesystemet ikke fungert etter intensjonen. Intensjonen med subsidiesystemet er at reineierne blir belønnet for å slakte mange rein. På denne måten kan reintallet reduseres samtidig som at reineierne kompenseres for dette tapet gjennom å motta subsidier. Det motsatte har skjedd. Reineierne øker reintallet, fordi flere rein betyr høyere inntekt fra både salg av kjøtt og subsidieordningen. Grunnen til at dette skjer er at subsidiene er knyttet til inntekt fra kjøttproduksjon. Høyere inntekt fra kjøttproduksjon gir mer subsidier. Målet om høyere økonomisk inntjening (økonomisk bærekraft) søkes oppnådd gjennom subsidieordningen. Målet om en økologisk bærekraftig reindrift søkes oppnådd gjennom både subsidieordningen og lovverket. Lovverket ble revidert i 1996 og erstattet med ny lov i 2007. I dag, 5 år etter at loven trådte i kraft, er situasjonen like vanskelig.
Description:	Paper 3 of this thesis is not available in Munin: 3. Ulvevadet, B. and Hausner, V. H.: 'Incentives and regulations to reconcile conservation and development : thirty years of governance of the Sami pastoral ecosystem in Finnmark, Norway', Journal of Environmental Management(2011), 92:2794-2802. Available at http://dx.doi.org/10.1016/j.jenvman.2011.06.026
URI:	http://hdl.handle.net/10037/4331

File(s) in this item: 4

paper_1.pdf (2.030Mb)

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thesis.pdf (1.331Mb)

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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The management of lobster in coastal Skagerrak : recreational fisheries, unreported commercial catches andmarine protected areas

Kleiven, Alf Ring (Doctoral thesis; Doktorgradsavhandling, 30-Sep-2010)

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Abstract:	The implementation of four experimental lobster reserves in Norway in 2006 highlighted a set of important questions regarding lobster management. This thesis presents a study on the management and fishery of the European lobster (Homarus gammarus) in Skagerrak. Firstly, the implementation process of the lobster reserves was analysed. It revealed that local stakeholders, such as recreational fishers, were positive to the use of reserves for management of lobster. However, they were not involved in the implementation process. By reviewing existing literature regarding recreational fisheries, we show that recreational fishers behave differently than commercial fishers. Recreational fishers are not dependent on making profit from the fishery and the value of recreational fishing to those who engage in it is a combination of catch and experience value. The latter implies that recreational fishers can continue fishing when stocks are at a low level, in the same way as subsidised commercial fisheries. We termed this self-subsidising: A fishery as one in which fishers subsidise themselves through an economic investment in gear and time from their non-fishery based earnings. Further, methods to estimate recreational, commercial and total effort and catch were developed. A probability-based strip transect survey method was developed and used to estimate the recreational and commercial effort in the fishery. The survey revealed that recreational fishers outnumber commercial fishers, contributing to 2/3 of the total effort (number of traps) during the season. Lastly, we collaborated with recreational fishers that reported catch and effort through catch diaries. Test validation from a random sample of fishers showed that the catch rate from those who filled out catch diaries could be considered as representative for the recreational lobster fishing population in the study area. We also found that mean recreational catch rates could be considered as representative for the catch rates in the commercial fishery. Our estimates show that recreational fishers represent 65 % of the total landings in the study area. In addition, 77 % of the lobsters caught by commercial fishers remain unreported. Hence, total catch from the recreational and commercial fishery combined, was estimated to be 14 times higher than the officially reported landings. The main conclusion in this thesis is that the lobster fishery can be considered unregulated: there are no quotas, no total effort regulations and no registry of participation from neither commercial nor recreational fisheries. The lack of data information may lead to mismanagement of the lobster fishery with the risk of further population reduction. Further, the positive attitude towards the lobster reserves, as expressed from the local stakeholders, clearly shows the potential in using lobster reserves as an important tool in the management of the European lobster in coastal Skagerrak. Implementation of more lobster reserves should strive to achieve stronger stakeholder involvement from the early start of the process in order to incorporate local user knowledge and ensure legitimacy of new reserves.
Description:	Papers 1 and 2 are not available in Munin: 1. Pettersen, A.R., E. Moland, E. Moland Olsen and J.A. Knutsen.: 'Lobster reserves in coastal Skagerrak - An integrated analysis of the implementation process', in E. Dahl, E. Moksness and J. Støttrup (ed), Coastal Zone Management (2009) Pages 178-188. Wiley-Blackwell Publishing. London. 2. Kleiven, A.R., E. Moland and U.R. Sumaila: 'Recreational fishing as a selfsubsidising activity : implications for sustainability of targeted fish stocks' (manuscript)
URI:	http://hdl.handle.net/10037/4093

File(s) in this item: 3

paper_3.pdf (301.5Kb)

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The potential for cooperation in shared fisheries : theory and application to Vietnam's fisheries strategy in the South China Sea

Long, Le Kim (Doctoral thesis; Doktorgradsavhandling, 05-Jun-2009)

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Abstract:	Since the end of the 20th century, many shared fish stocks throughout the world have been found in extreme danger of collapse. There are many calls for cooperation in utilizing and conserving the shared fish resources including the 1982 UN Convention on the Law of the Sea and the 1995 UN Fish Stock Agreement. This study provides an important rationale for cooperation in utilizing a shared fish stock with several interested parties. The rationale is that an increase in the cooperation level leads to an increase not only in the steady-state fish stock, but also in total rent of the fishery. Moreover, the possibilities for cooperation in utilizing shared fisheries are examined. Some measures are also proposed to improve the cooperation level. According to this study, the prospects of cooperation in utilizing a straddling fish stock are not unlikely if a Regional Fishery Management Organisation (RFMO) forms with a leading role in a Stackelberg game or with an endogenous minimum participation level in a Cournot game. However, if the cost of enforcing RFMO members’ compliance with the terms of the agreement is high enough, there may not be any incentive for fishing countries to establish an RFMO for managing a straddling fish stock. This is one of the reasons for pervasive over-fishing around the world. For an actual example, the South China Sea (SCS) fishery, which is harvested by about ten countries including Vietnam, will be discussed as an application. An empirical investigation of the profitability and remuneration of an offshore long-line fishery demonstrates slightly above-average earnings even under the current open-access regime. Finally, the study will propose some fishery strategies for Vietnam, which is a country with heavy inshore fishing, the second largest catch in the South China Sea and where large-scale illegal fishing takes place.
Description:	The papers of the thesis are not available in Munin: 1. Le Kim Long: «Regional fisheries management organisation with an endogenous minimum participation level for cooperation in straddling stock fisheries», in press-version, published in Fisheries Research, Volume 97, Issues 1-2, April 2009, Pages 42-52 (Elsevier; publisher's restrictions). Available at http://dx.doi.org/10.1016/j.fishres.2008.12.014 2. Le Kim Long and Ola Flaaten: «A Stackelberg Analysis of the Potential for Cooperation in Straddling Stock Fisheries» (manuscript) 3. Le Kim Long, Ola Flaaten and Nguyen Thi Kim Anh: «Economic performance of open-access offshore fisheries—The case of Vietnamese longliners in the South China Sea», Fisheries Research 93 (2008), 296–304(Elsevier; publisher's restrictions). Available at http://dx.doi.org/10.1016/j.fishres.2008.05.013 4. Le Kim Long: «On the shared fisheries in the South China Sea and possible strategies for Vietnam’s fisheries» (manuscript)
URI:	http://hdl.handle.net/10037/2582

File(s) in this item: 1

thesis.pdf (1.093Mb)

Trophic relationships and the role of Calanus in the oceanic ecosystems south and north of Iceland

Pétursdóttir, Hildur (Doctoral thesis; Doktorgradsavhandling, 03-Dec-2012)

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Abstract:	The waters south and north of Iceland vary greatly both oceanographically and biologically with the rather stable and warm Atlantic waters south and west of Iceland and the more variable and cold Arctic and sub-Arctic waters, north and east of Iceland. The aim of this study was to increase the knowledge on the role of Calanus copepods and trophic relations of the key components of the oceanic ecosystems south-west (over the Reykjanes Ridge) and north (in the Iceland Sea) of Iceland. The trophic relationships and energy transfer to higher trophic levels were estimated by using fatty acid trophic markers, by comparing fatty acid profiles among species and by applying stable isotopes of carbon and nitrogen. The inter-annual variability in abundance and community composition of zooplankton on the shelves south and north of Iceland in relation to environmental condition in spring were also observed. The energy rich Calanus species are key links between primary producers and higher trophic levels in the Icelandic waters. The Calanus species dominate the zooplankton biomass around Iceland and their markers (20:1n9 and 22:1n11) are found in high amount in animals at higher trophic levels. Calanus finmarchicus plays important role as a forage species in the Atlantic water south-west of Iceland while its high importance is replaced by the larger lipid rich C. hyperboreus in the Arctic and sub-Arctic waters north of Iceland. Even though Calanus based food-web is the main driver in both areas, there exist a pathway where Calanus species are of less importance and the energy is channeled via euphausiids to higher trophic levels. Around four trophic levels were observed in the two oceanic ecosystems where adult fish occupied the highest trophic levels. Over the Reykjanes Ridge vertically migrating mesopelagic fish, in pronounced deep-scattering layers, are actively bringing energy to deeper layers by feeding on C. finmarchicus in the upper layers. In the Iceland Sea comparable deep-scattering layers were not observed. Epipelagic schools of capelin (Mallotus villosus) are important component of the pelagic ecosystem in the Iceland Sea. After feeding intensively in the Iceland Sea, they migrate and thus transfer the energy to adjacent ecosystems. The ecosystem around Iceland is extremely sensitive to climate variations. Increase in sea temperature has been related to shift in distribution and feeding migrations of capelin in the Iceland Sea with the result of diet switch of older capelin. The importance of the Arctic amphipod Themisto libellula in the diet of adult capelin increased in their new distribution area in the colder western part of the Iceland Sea. A shift in distribution of species may thus influence the whole ecosystem structure and food web interactions in larger area. This study presents novel important knowledge on the food web structures and carbon flow in Icelandic waters.
Description:	The papers of this thesis are not available in Munin: 1. Petursdottir, H., Gislason, A., Falk-Petersen, S., Hop, H., and Svavarsson, J.: 'Trophic interactions of the pelagic ecosystem over the Reykjanes Ridge as evaluated by fatty acid and stable isotope analyses', Deep-Sea Research Part II (2008), 55:83-93. Available at http://dx.doi.org/10.1016/j.dsr2.2007.09.003 2. Petursdottir, H., Gislason, A., and Falk-Petersen, S.: 'Lipid classes and fatty acid compositions of muscle, liver and skull oil in deep-sea redfish Sebastes mentella over the Reykjanes Ridge', Journal of Fish Biology (2008), 73:2485–2496. Available at http://dx.doi.org/10.1111/j.1095-8649.2008.02100.x 3. Petursdottir, H., Falk-Petersen, S. and Gislason, A.: 'Trophic interactions of meso- and macrozooplankton and fish in the Iceland Sea as evaluated by fatty acid and stable isotope analysis', ICES Journal of Marine Science (2012), 69:1277-1288. Available at http://dx.doi.org/10.1093/icesjms/fss125 4. Pálsson, Ó.K., Gislason, A., Guðfinnsson, H.G., Gunnarsson, B., Ólafsdóttir, S.R., Petursdottir, H., Sveinbjörnsson, S., Thorisson, K. and Valdimarsson, H.: 'Ecosystem structure in the Iceland Sea and recent changes to the capelin (Mallotus villosus) population', ICES Journal of Marine Science (2012), 69:1242-1254. Available at http://dx.doi.org/10.1093/icesjms/fss071 5. Gislason, A., Petursdottir, H., Astthorsson, O.S., Gudmundsson, K. and Valdimarsson, H.: 'Inter-annual variability in abundance and community structure of zooplankton south and north of Iceland in relation to environmental conditions in spring 1990-2007', Journal of Plankton Research (2009), vol.31, no.5:541-551. Available at http://dx.doi.org/10.1093/plankt/fbp007
URI:	http://hdl.handle.net/10037/4661

File(s) in this item: 1

thesis.pdf (1.998Mb)

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)

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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

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Abstract:	Spectral effects of microbial growth, packaging atmosphere and heme oxidation were investigated with fresh salmon. The presence of microorganisms and their growth have little effect on the development of spectral features in fresh salmon during storage prior to extensive spoilage. Important spectral changes occur at 606 and 636 nm in the spectra of fresh salmon during storage. Heme oxidation is the primary source of spectral changes occurring at 636 nm in fresh salmon fillets during air storage. The origin of the shoulder peak appearing at 606 nm is absorption due to water in the salmon muscle. The spectral variations at 606 nm depend on the dominant oxidation state of heme in the muscle and the change in the visibility of the water shoulder peak in the spectrum.
Description:	The papers of this thesis are not available in Munin: 1. Sone, I., Olsen, R.L., Dahl, R. & Heia, K.: 'Visible/near-infrared spectroscopy detects autolytic changes during storage of Atlantic salmon (Salmo salar L.)', Journal of Food Science (2011), vol.76, no.3:203-S209. Available at http://dx.doi.org/10.1111/j.1750-3841.2011.02062.x 2. Sone, I., Olsen, R.L., Sivertsen, A.H., Eilertsen, G. & Heia, K.: 'Classification of fresh Atlantic salmon (Salmo salar L.) fillets stored under different atmospheres by hyperspectral imaging', Journal of Food Engineering (2011), vol.109, no.3:482-489. Available at http://dx.doi.org/10.1016/j.jfoodeng.2011.11.001 3. Sone, I., Olsen, R.L., & Heia, K.: 'Spectral changes of Atlantic salmon (Salmo salar L.) muscle during cold storage as affected by the oxidation state of haem', Journal of Agricultural and Food Chemistry (2012), vol.60, no.38:9719–9726. Available at http://dx.doi.org/10.1021/jf302505y
URI:	http://hdl.handle.net/10037/4656

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