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Doktorgradsavhandlinger (BFE-fak)
Browsing Doktorgradsavhandlinger (BFE-fak) by Author

Browsing Doktorgradsavhandlinger (BFE-fak) by Author

Now showing items 57-76 of 76

Consideration set size and choice in fish consumption : the influence of attitude, knowledge, convenience, and category presentation

Rørtveit, Asbjørn Warvik (Doctoral thesis; Doktorgradsavhandling, 11-Jun-2010)

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Abstract:	Purpose – Three main objectives are defined in this thesis: 1) To determine the extent to which the nature of a consideration set affects consumer choice; 2) To investigate how consumer attitudes, knowledge, and convenience motivations affect the formation of a consideration set; and 3) To investigate how category presentation moderates the relationship between convenience motivations and consideration set composition. Design/methodology/approach – Different research designs, several data sources, and different analytical procedures are employed in four papers. Papers #1, #2, and #3 use survey designs and are based on two large (n > 1000) cross-sectional datasets. Data in these papers are analyzed using structural equation modeling in LISREL 8.72. Paper #4 is based on two laboratory experiments (n = 150) with 2 × 2 between-subject factorial designs. Data in Paper #4 are analyzed using a two-way ANOVA in SPSS. Findings and contribution – This dissertation shows that consideration set size is important in explaining a consumer's choice and consumption of food, and is influenced by individual consumer variables such as attitude, knowledge, perceived inconvenience, and convenience orientation. Procedural knowledge is shown to be especially important for the number of food alternatives considered. In addition, the research in this dissertation demonstrates how situational and occasional factors such as availability and the urge to save time or effort (convenience) can affect aspects of consideration set attributes: stability, variety, and size. Importantly, the studies in this dissertation show that these relationships are moderated by the ways food is presented to the consumer (category presentation). While the overall findings are in accordance with previous research on consideration sets, this dissertation builds on and extends the past research by exploring the relationship between convenience and consideration set characteristics. The moderating influence of category presentation on the relationship between convenience motivations and consideration set characteristics is an especially important contribution of this dissertation research. Practical implications – Because the likelihood of being chosen is affected by the size of the consideration set, food producers should advocate that consumers should consider preparing their products in as many ways and in as many combinations with side ingredients as is reasonable. Furthermore, food marketers should focus on activities that enhance the consumer’s direct product experience through testing, trials, tasting, and samples, since procedural knowledge is shown to be of major importance for the number of considered alternatives. If marketers can identify cut-off values of salient attributes such as the time and effort spent on dinner preparation for a particular segment, they will have the ability to position products in accordance with these factors and thereby enhance the possibility of being considered. Furthermore, the moderating effect of category presentation on the relationship between the urge to save time and consideration set (stability, variety, and size) has several practical implications for marketing issues, such as advertising, placement in the retail store, shelf labeling, product development, and package labeling. Research limitations – A limitation of this study is that the relationship between the consideration set and choice was only tested for size dimensions of the consideration set. Future research may focus on the relationship between all the different dimensions of the consideration set (stability, variety, preference dispersion, and size) and choice, at both taxonomic and script category level. In addition, in future research the relationship between knowledge and consideration set (stability, variety, and preference dispersion) should be investigated, because of the close relationship between knowledge and consideration set size shown in this dissertation. Finally, the moderating effect of category presentation is one of the major contributions of this dissertation. These findings should be validated in similar and alternative empirical settings and designs in future research. Originality/value – The findings of this dissertation are in accordance with previous research in the field. The findings also have implications for future theory development and research, as well as practical implications and benefits for the marketing strategy decisions of producers and businesses.
Description:	The papers of the thesis are not available in Munin: 1. Rortveit, A. W. & Olsen, S. O.: «The role of consideration set size in explaining fish consumption», Appetite, 49(1)(2007): 214–222 (Elsevier - publisher's restrictions). Available at http://dx.doi.org/10.1016/j.appet.2007.02.005 2. Rortveit, A. W. & Olsen, S. O.: «Combining the role of convenience and consideration set size in explaining fish consumption in Norway», Appetite, 52(2)(2009): 313–317 (Elsevier - publisher's restrictions). Available at http://dx.doi.org/10.1016/j.appet.2008.11.001 3. Rortveit, A. W. & Olsen, S. O.: «The effects of consumer knowledge on consideration set size» (manuscript) 4. Rortveit, A. W., Haugtvedt, C. P., & Olsen, S. O.: «Goal-derived categories and convenience: Influences on consideration set formation» (manuscript)
URI:	http://hdl.handle.net/10037/2698

File(s) in this item: 1

thesis.pdf (612.2Kb)

Determinants and effects of moth population dynamics in altitudinal gradients in northern Fennoscandia

Schott, Tino (Doctoral thesis; Doktorgradsavhandling, 21-May-2013)

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Abstract:	The aim of this PhD-project has been to increase our knowledge of trophic interactions along altitudinal gradients in a system of sympatric, cyclically outbreaking geometrid moth species in sub-arctic, coastal birch forest in northern Norway. The project resulted in four scientific publications; two sub-studies focused on the causal effect of natural enemies on the observed complex spatio-temporal dynamics of the moth species (Papers 1 & 2). The other two sub-studies investigated the ecological effects of variable moth larvae densities as a resource for predators in the sub-Arctic ecosystem (Papers 3 & 4). In paper 1, we rejected the hypothesis that larval parasitoids might terminate moth population peaks, one of the most important hypotheses on insect population regulation. We, however, found that larval parasitoids can influence local spatial variation in moth population density. Hence, we concluded that spatial replication of sampling sites is crucial to arrive at non-biased estimates for the temporal effect of larval parasitoids on host populations. The long enduring debate on the regulation potential of parasitoids on insect populations in the scientific literature may be viewed in light of our findings. Similarly, in Paper 2, we tested if the often-observed spatial outbreak patterns of moth populations might be a result of release from invertebrate predators. Along mountain slopes, moth outbreaks in northern Fennoscandia often occur close to the tree line, and we tested if the abundance of ground dwelling invertebrate predators was inversely correlated with altitude, testing the assumption that moth outbreaks may be a result of reduced predation impact at high altitudes. As our analyses could not reveal this predicted pattern, we rejected the hypothesis. Consequently, the first two sub-studies delimitated the number of candidate factors that might shape Fennoscandian moth dynamics by reevaluating the role of larval parasitoids and ground-dwelling invertebrate predators. In paper 3, we reanalyzed the data from Paper 1 from the parasitoid's perspective by determining the dependencies of individual parasitoid species to host densities. For comparison, we also estimated the strength of effects hidden in the spatial and temporal attributes of altitude and year on parasitoid prevalence rates. We found that altitude and year, rather than host density, explained by far most of the extra-binomial variation in the parasitoid prevalence data. Hence, we concluded that unknown factors, which co-vary with altitude and year, dominate the prevalence dynamics of the larval parasitoids in our study and, consequently, act to decouple parasitoid dynamics from the dynamics of their hosts. Moth larvae as a resource for predators were also the focal issue in Paper 4, which focused on the importance of prey availability and forest phenology for breeding parameters in the two passerine birds great tit and pied flycatcher. The study was based on the phenological conflict that spring arrives in mountain slopes first at low altitude, while the bird's main food resource during the breeding season (i.e. moth larvae) often dominates forest habitat at higher altitude. Thus, we tested if passerine birds select breeding habitat according to the onset of spring or the availability of moth larvae and if the two bird species differed in this respect. We found that the phenological timing was the main driving force for both species when selecting breeding habitat lowest in the gradients where spring arrived first. However, also the positive correlations with moth larvae density appeared to be significant in our analyses. The main difference between the two species was found in the timing strategy for egg laying and size of clutches, which might make the great tit more prone to mismatch during springs of lower temperature. In addition, while nest box occupancy decreased with altitude in both species, the same relationship with respect to clutch size was only found for pied flycatchers, but not for great tits. Finally, great tits were more prone to fail during their breeding attempt and we concluded that the pied flycatcher, by laying eggs up to two weeks after great tits, appears to be the better adapted species with respect to breedig at sub-arctic conditions. This PhD-thesis strengthens the view that so-called top-down interactions in the ecological moth system in northern Fennoscandia cannot explain complex moth population dynamics, but that moth larvae can be regarded as a valuable resource for species at other trophic levels. The consistent dominance of altitude and year in all our analyses, on the other hand, suggests that explanations for the complex spatio-temporal moth population dynamics ought to be looked for in mechanisms ruled by environmentally governed processes such as phenology.
Description:	The papers of this thesis are not available in Munin: 1. Schott T., Hagen S.B., Ims R.A. & Yoccoz N.G.: 'Are population outbreaks in sub-arctic geometrids terminated by larval parasitoids?', Journal of Animal Ecology (2010), vol.79:701-708. Available at http://dx.doi.org/10.1111/j.1365-2656.2010.01673.x 2. Schott T., Kapari L., Hagen S.B., Vindstad O.P.L., Jepsen J.U. & Ims R.A.: 'Predator release from invertebrate generalists does not explain geometrid moth outbreaks at high altitudes', The Canadian Entomologist (2013), vol.145:184-192. Available at http://dx.doi.org/10.4039/tce.2012.109 3. Schott T., Ims R.A., Hagen S.B. & Yoccoz N.G.: 'Sources of variation in larval parasitism of two symmetrically outbreaking birch forest defoliators', Ecological Entomology (2012), vol. 37:471-479. Available at http://dx.doi.org/10.1111/j.1365-2311.2012.01386.x 4. Schott T., Svavarsdottir S., Hagen S.B., Kapari L., Vindstad O.P.L., Biuw M., Jepsen J.U. & Ims R.A.: 'Coping with variation in prey abundance and phenology: Comparative breeding performance of two passerines at the northern limit of their geographic range' (manuscript).
URI:	http://hdl.handle.net/10037/5159

File(s) in this item: 1

thesis.pdf (3.351Mb)

Planktonic food webs in the Arctic Ocean : structure and function in contrasting seasons and physical settings across Fram Strait

Seuthe, Lena (Doctoral thesis; Doktorgradsavhandling, 08-Dec-2011)

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Abstract:	This thesis investigates the structure and function of planktonic food webs at two sites between Greenland and the Svalbard Archipelago, covering a coastal ecosystem influenced by Atlantic water masses (Kongsfjorden, 78º N) and a more oceanic system off the East Greenlandic shelf, influenced by the outflow of Arctic water and sea ice from the Arctic Ocean (northwest Fram Strait, 75 - 80º N). In Kongsfjorden, a seasonal study was conducted with sampling at six occasions between March and December 2006. Logistical constrains prohibited a similar extensive seasonal investigation in the ice-covered waters of northwest Fram Strait. Sampling fell into the onset (April-May 2008) and end (September 2006/2007) of the productive season. All four studies investigated the stocks of pico- to micro-sized autotrophs and heterotrophs, i.e. heterotrophic bacteria, proto- and metazooplankton. Production rates of autotrophs and heterotrophic bacteria were measured in Kongsfjorden. Ratios of heterotrophic and autotrophic biomass (H:A) and of specific bacterial and primary production (µBac:µPhyto) allowed to asses the overall structure and function of the investigated planktonic food webs and to compare them to published data from other Arctic regions. The emerging picture provides three distinct food web modes, where mode A is characterized by H:A < 1 and µBac:µPhyto > 1, new production, and large-celled phytoplankton. Mode B and C are characterized by dominance of heterotrophs (H:A > 1), more regenerated production, and small-celled phytoplankton. The difference between mode B and C is a difference in the specific production ratio, with µBac:µPhyto smaller and larger 1, respectively. According to this scheme, Arctic plankton communities appear to prevail under mode B and C most of the year. In Kongsfjorden, e.g. five of the six months sampled fell under mode B and C, with mode C being typical for light-limited winter communities. From own and literature data, it is suggested that the food web mode controlling physical factors are the amount of incident photosynthetically active radiation (PAR), ice cover, nutrient concentration, and water column stability. Due to an approximately latitudinal change in these physical settings, the relative prevalence of the three food web modes changes from the marginal seas to the central Arctic Ocean, with mode A most likely being absent from the highest latitude waters. In general, Arctic plankton communities appear to sustain on average a 3-fold higher H:A biomass ratio for a given phytoplankton stock than the world’s coastal oceans, which may mainly be due to extensive import of long-lived copepods from sub-Arctic European seas through advection. It is argued that the large stock of heterotrophs plays a crucial role in structuring Arctic plankton communities, with the potential to prohibit phytoplankton bloom formation (mode A) through extensive grazing.
Description:	Paper 3 and 4 of this thesis are not available in Munin: 3. Seuthe L, Töpper B, Reigstad M, Thyrhaug R and Vaquer-Sunyer R: 'Microbial communities and processes in ice-covered Arctic waters of the northwestern Fram Strait (75 – 80ºN) during the vernal pre-bloom phase', Aquatic Microbial Ecology (2011) 64:253-266. Available at http://dx.doi.org/10.3354/ame01525 4. Svensen C, Seuthe L, Vasilyeva Y, Pasternak A and Hansen E: 'Zooplankton communities across Fram Strait in autumn : are small copepods and protozooplankton important? (in press in Progress in Oceanography).
URI:	http://hdl.handle.net/10037/3777

File(s) in this item: 3

paper_1.pdf (1.039Mb)

paper_2.pdf (966.8Kb)

thesis.pdf (2.535Mb)

Green sea urchin (Strongylocentrotus droebachiensis,Müller) in aquaculture: the effects of environmental factors on gonad growth.

Siikavuopio, Sten Ivar (Doctoral thesis; Doktorgradsavhandling, 30-Oct-2009)

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Abstract:	Ved hjelp av eksperimentelle studier har en undersøkt effekten av ulike miljøfaktorer på gonadevekst hos Drøbak-kråkebolle i oppdrett. Dette inkluderer effekten av temperatur, størrelse, sesong, individtetthet og forskjellige vannkvalitetsparametre (O2, CO2, nitritt, ammoniakk) og håndtering på overlevelse, gonadevekst, fôrinntak og fôrutnyttelse. Optimal temperatur for gonadevekst hos voksne kråkeboller ligger mellom 10 og 12 ºC om sommeren og ca 8 ºC om vinteren. Temperaturer over 12 ºC gir redusert vekst og fôrutnyttelse. Studiene viser at Drøbak-kråkebollen har lav toleranse for CO2, nitritt og ammoniakk sammenliknet med laksefisk. Forhøyede nivåer av disse stoffene medfører redusert gonadevekst, mens fôrinntaket blir lite påvirket. Dette resulterer i svært dårlig fôrutnyttelse. Kråkebollene har lavt oksygenforbruk, men er likevel svært følsomme for reduksjoner i vannets oksygeninnhold. Disse forholdene tilsier at kråkeboller i oppdrett krever stor vannutskifting for å opprettholde maksimal gonadevekst. For høy individtetthet i oppdrett medfører også nedsatt gonadevekst. Arbeidet omfatter en kartlegging av akseptabel tetthet for kråkebolle i oppdrett.
Description:	Papers number 1, 2, 3, 5, 6, 7, 8, 9 and 10 of the thesis are not available in Munin due to publishers' restrictions: 1. Siikavuopio, S. I., Mortensen. A., Christiansen, J. S.: "Effects of body weight and temperature on feeding, gonad growth and oxygen consumption in green sea urchin, Strongylocentrotus droebachiensis." Aquaculture 2008; 281, 77-82 (Elsevier). Available at http://dx.doi.org/http://dx.doi.org/10.1016j.aquaculture.2008.05.033> 2. Siikavuopio, S. I., Christiansen, J.S., Dale, T.: "Effects of temperature and season on gonad growth and feed intake in the green sea urchin (Strongylocentrotus droebachiensis)." Aquaculture 2006; 255, 389-394 (Elsevier). Available at http://dx.doi.org/http://dx.doi.org10.1016j.aquaculture.2005.12.021 3. Siikavuopio, S. I., Christiansen, J. S., Sæther, B-S., Dale, T.: "Seasonal variation in feed intake under constant temperature and natural photoperiod in the green sea urchin (Strongylocentrotus droebachiensis)." Aquaculture 2006; 272, 328-334 (Elsevier). Available at http://dx.doi.org/http://dx.doi.org/10.1016/j.aquaculture.2007.09.003 5. Siikavuopio, S. I., Dale, T., Foss, A., Mortensen, A.: "Effects of chronic ammonia exposure on gonad growth and survival in green sea urchin, Strongylocentrotus droebachiensis." Aquaculture 2004; 242, 313-320 (Elsevier). Available at http://dx.doi.org/10.1016j.aquaculture.2004.08.042 6. Siikavuopio, S. I., Dale, T., Christiansen, J. S., Nevermo, I.: " Effects of chronic nitrite exposure on gonad growth in green sea urchin, Strongylocentrotus droebachiensis." Aquaculture 2004; 242, 357-363 (Elsevier). Available at http://dx.doi.org/10.1016/j.aquaculture.2004.09.007 7. Siikavuopio, S. I., Dale, T., Mortensen, A., Foss, A.: " Effects of hypoxia on feed intake and gonad growth in the green sea urchin (Strongylocentrotus droebachiensis)." Aquaculture 2007; 266, 112-116 (Elsevier). Available at http://dx.doi.org/10.1016j.aquaculture.2007.02.028 8. Siikavuopio, S. I., Mortensen, A., Dale, T., Foss, A.: " Effects of carbon dioxide exposure on feed intake and gonad growth in green sea urchin (Strongylocentrotus droebachiensis)." Aquaculture 2007; 266, 97-101 (Elsevier).Available at http://dx.doi.org/10.1016/j.aquaculture.2007.02.044 9. Siikavuopio, S. I., Dale, T., Mortensen, A.: " The effects of stocking density on gonad growth, survival and feed intake of adult green sea urchin (Strongylocentrotus droebachiensis)." Aquaculture 2007; 262, 78-85 (Elsevier). Available at http://dx.doi.org/10.1016/j.aquaculture.2006.09.045 10. Christiansen, J. S., Siikavuopio, S. I.: "The relationship between feed intake and gonad growth of single and stocked green sea urchin (Strongylocentrotus droebachiensis) in a raceway culture." Aquaculture 2007; 262, 163-167 (Elsevier). Available at http://dx.doi.org/10.1016/j.aquaculture.2006.09.043
URI:	http://hdl.handle.net/10037/2263

File(s) in this item: 2

paper_4.pdf (248.9Kb)

thesis.pdf (579.4Kb)

Animal-habitat relationships in high altitude rangelands

Singh, Navinder J. (Doctoral thesis; Doktorgradsavhandling, 18-Sep-2008)

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Abstract:	This study conducted in the high altitude rangelands of Indian Transhimalaya, deals with basic questions regarding the ecology of an endangered species, the wildsheep Tibetan argali (Ovis ammon hodgsoni) and applied issues related to its conservation and potential conflict with the local nomadic pastoralists. The basic questions on ecology are aimed at delineating the habitat and resource selection processes, identifying factors causing sexual segregation and efficient surveying and sampling. The applied aspect focuses on the changing face of pastoralism and the potential impacts of modernising livestock husbandry on argali. Overall, the study provides a general framework towards the understanding of argali-habitat relationships at different spatio-temporal scales. The spatial determinant associated with altitude in the area, predicts argali habitat and resource selection in this relatively homogenous landscape. These determine the range of other topographic variables and forage characteristics selected by argali. The selection of feeding patches in the selected range of altitude and topography is mainly characterised by their greenness and the quality of plant groups. Adjusting to changing forage quality, argali display an opportunistic feeding strategy, selecting grasses in early spring and switching to forbs later in summer. Nevertheless, the habitat selection process did not appear to differ among the sexes to drive sexual segregation. There was, however, strong segregation among the sexes as well as between lactating and non lactating females. The reasons for segregation appeared to be predominantly social, but driven ultimately by predation and concomitantly by resources. The habitat selection information was used to design a stratified random sampling strategy that led to i) a significant reduction in survey effort in sampling these sparsely distributed species and ii) reduction in sampling bias. The applied aspect of the study outlines and evaluates the dramatic changes in the nomadic pastoralism that have occurred in the past five decades in the study area. These have led to a loss of pastures (-25 to -33%) of the nomads, consequent readjustment in traditional patterns of pasture use, intensified grazing pressures (25 to 70%) and rangeland degradation in the area. Such changes may have serious consequences on the survival of local wildlife, as tested with a study of the effects on argali of livestock presence and resource exploitation. Hence, a successful conservation and recovery strategy should focus on: minimising the impacts of livestock on argali, identifying the factors affecting the persistence of the current populations, increasing local sub populations of this species to prevent extinction due to stochastic events, prevent loss of genetic diversity and excessive fragmentation and thus ensuring gene flow. Ecological Niche Factor Analyses (ENFA), bias-reduced logistic regression and Fuzzy correspondence analyses (FCA) were used to answer habitat and resource selection questions. A sexual segregation and aggregation statistic (SSAS) was used to estimate the components of sexual segregation and test segregation. SSAS combined with canonical correspondence analyses (CCA) allowed the estimation of segregation based on habitat variables. Logistic regression models were formulated to estimate models on which the stratified random sampling strategy was based. The Animal - Habitat relationships in high altitude rangelands overall study also included surveys, interviews and literature reviews to understand the nomads’ movement and pasture use patterns of their livestock. Kernel density estimations (KDE) were used to estimate extent of range overlaps between livestock and argali.
Description:	The papers of the thesis are not available in Munin: 1. Navinder J Singh, Nigel G Yoccoz, Nicolas Lecomte, Steeve D Côté and Joseph L Fox: «Scale and selection of habitat and resources: Tibetan argali in high altitude rangelands» (manuscript). Published version, Can. J. Zool. 88: 436-447 (2010), available at http://dx.doi.org/10.1139/Z10-015 2. Navinder J Singh, Christophe Bonenfant, Nigel G Yoccoz and Steeve D Côté: «Proximate and ultimate causes of sexual segregation in eurasian wildsheep, the Tibetan argali (Ovis ammon hodgsoni)» (manuscript). Later published (with altered title) in Behavioral Ecology, 2010, 21(2):410-418, available at http://dx.doi.org/10.1093/beheco/arp205 3. Navinder J Singh, Nigel G Yoccoz, Yash Veer Bhatnagar and Joseph L Fox: «Using resource selection functions to sample rare species in high-altitude ecosystems: a case study with Tibetan argali» (manuscript). Later published (with altered title) in Biodiversity and Conservation, Volume 18, Number 11, October 2009, available at http://dx.doi.org/10.1007/s10531-009-9615-5 4. Navinder J Singh, Joseph L Fox, Yash Veer Bhatnagar, Nicolas Lecomte and Nigel G Yoccoz: «Changing nomadic pastorialism in transhimalyan rangelands of India - causes and consequences» (manuscript). 5. Singh, N.J., Bhatnagar, Y.V., Yoccoz, N.G. and Fox, J L: «Assessing wildlife-livestock interaction in Indian transhimalya: Tibetan argali as a case study» (manuscript) 6. Navinder J. Singh, Joseph L. Fox and Yash Veer Bhatnagar: «Tibetan argali in India, Nepal and the western Tibet autonomous region, China», chapter in Richard P Reading (Ed): «Argali biology and conservation», Denver Zoological Foundation (In press).
URI:	http://hdl.handle.net/10037/2574

File(s) in this item: 1

thesis.pdf (9.332Mb)

Diversity along a speciation continuum : ecology and morphology of northern European whitefish (Coregonus lavaretus)

Siwertsson, Anna (Doctoral thesis; Doktorgradsavhandling, 24-Aug-2012)

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Abstract:	How new species are formed is still a major question in evolutionary biology. In ecological speciation, natural selection drives the evolution of slight distinctions between individuals into extensive differences between species. In this thesis, early stages of an ecologically driven speciation process are addressed using ecological and morphological data from a large number of European whitefish (Coregonus lavaretus) populations in northern Fennoscandia. Northern Fennoscandia is an area scattered with lakes created during the glacial retreat (~10-12 kyr BP). Many of these lakes are inhabited by one or up to three different morphs of whitefish. As many other temperate freshwater fishes, whitefish typically diverge into pelagic and littoral resource specialists, the densely rakered (DR) and the large sparsely rakered (LSR) morph, respectively. Parallel within-lake divergence is the most probable origin of these sympatric morphs. In addition, a third whitefish morph (the small sparsely rakered; SSR), specializing on profundal resources, was recently described in a few lakes in the area. The aims of this thesis were to explore and document the phenotypic diversity of whitefish in northern Fennoscandia, and to investigate some of the factors limiting the level of diversity reached within each lake. Further, the ability of LSR whitefish morphs to utilize profundal resources was explored, as this is a probable origin of profundal specialist SSR morphs. Based on the distribution of gill raker number, a temporally stable morphological trait in the studied populations, I have documented a continuum of increasing diversity in northern Fennoscandian whitefish. This whitefish diversity comprises mono (only LSR), di- (LSR and DR), and tri-morphic (LSR, DR and SSR) populations, in addition to intermediate stages between them. Within three different lakes with dimorphic whitefish populations, some individuals of the LSR morph were specialized to exploit profundal resources. This could indicate an incipient evolution towards a profundal specialist morph (SSR) in some dimorphic lakes. Ecological opportunity (lake size and productivity) is likely a prerequisite for whitefish to diverge, although limitations related to the colonization history also were present. In conclusion, there is astonishing parallel divergence in ecology, morphology and genetics along a continuum of increasing diversity in whitefish. Thus, ecologically-based natural selection is likely driving the divergence, promoting reproductive isolation and incipient ecological speciation in northern Fennoscandian whitefish populations.
Description:	Papers 1,3 and 4 of this thesis are not available in Munin: 1. Anna Siwertsson, Rune Knudsen and Per-Arne Amundsen: 'Temporal stability in gill raker numbers of subarctic European whitefish populations', Advances in Limnology (2012), vol. 63:229-240. Available at http://www.schweizerbart.de/papers/adv_limnology/detail/63/77932/Temporal_stability_ingill_raker_numbers_of_subarct 3. Anna Siwertsson, Rune Knudsen, Kim Præbel, Colin E. Adams, Jason Newton and Per-Arne Amundsen: 'Discrete foraging niches promote ecological, phenotypic, and genetic divergence in sympatric whitefish (Coregonus lavaretus)', (accepted manuscrip) 4. Anna Siwertsson, Rune Knudsen, Colin Adams and Per-Arne Amundsen: 'Replicated morphological divergence supports incipient ecological morph formation in European whitefish (Coregonus lavaretus)', (manuscript)
URI:	http://hdl.handle.net/10037/4566

File(s) in this item: 2

paper_2.pdf (1.450Mb)

thesis.pdf (4.188Mb)

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

File(s) in this item: 2

paper_3.pdf (4.055Mb)

thesis.pdf (1.078Mb)

Interactions between small rodents and their food plants in tundra habitats

Soininen, Eeva Marjatta (Doctoral thesis; Doktorgradsavhandling, 19-Oct-2012)

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Abstract:	Small rodents are key herbivores of arctic ecosystems, where their cyclic population dynamics have important implications for vegetation dynamics. The role of vegetation for shaping small rodent population dynamics remains, however, unclear. Evaluation of this interaction has been greatly hampered by the rather fragmentary knowledge of small rodents feeding ecology, which in turn is due to methodological challenges in studying small rodent diets. In this thesis, I investigated interactions between small rodents and vegetation, focusing on variability of both diets and plant defences induced by rodent herbivory. In order to overcome limitations set by methods, I have evaluated the use of two recently developed methods and one traditionally used method for studying small rodent diets. I found that novel DNA metabarcoding methods give the best taxonomic resolution whereas traditional microhistological methods may still be useful to elucidate which plant parts have been eaten. Moreover, use of stable isotope analysis in research of small rodent feeding habits can be useful when evaluating the temporal persistence of diets. In three observational studies, I described diets of small rodents in tundra habitats and assessed sources of variability in them. I found that diets of my study species were more diverse than previously believed, suggesting that diversity is an important but previously underrated trait of small rodent diets. Nutritional quality seems to determine which food items are preferred, as small rodents selected in general for most palatable food items. In addition to nutritional drivers, my results suggest that various ecological drivers, such as food availability, competition and predation risk avoidance, are important determinants of for small rodent diets in the wild. A better incorporation of ecological and nutritional drivers into a common framework is therefore needed to understand what shapes diets of small rodents, and herbivores in general, in natural habitats. I evaluated the impact of herbivory on grass silica defences in an experimental study. I found that levels of such defences vary between locations, probably due to heritable differences among grass populations in the response to herbivory and differences in local growth conditions. Based on such spatial variation and the large proportion of other food items included in the diets of the focal small rodent populations, it is unlikely that silica-based defences would have a strong direct role in shaping small rodent population dynamics in Finnmark. However, increased levels of silica in grasses reduce grass palatability for rodents, and hence probably impact rodent diet quality indirectly, through a shift to diets with less grasses. I therefore suggest that availability of alternative food items is likely to be an important factor shaping the interaction between small rodents and grasses. Variability in both small rodent diets and plant defences suggests that interaction between vegetation and a small rodent species may show pronounced spatial variation. This, together with my findings on the diversity of diets and its increase during high population densities, indicates that a single plant defence mechanism is unlikely to shape rodent-vegetation interactions. I suggest that deeper understanding of the role of food for small rodent population dynamics could rather be gained by focusing on the compensatory nutritional effects of different food items as well as diet diversity.
Description:	Papers 2, 3, 4 and 5 are not available in Munin: 2. Soininen E.M., Zinger L., Gielly L., Bellemain, E., Br athen, K.A., Brochmann, C., Epp, L.S., Gussarova, G., Hassel, K., Henden, J.-A., Killengreen, S.T., R am a, T., Sten ien, H.K., Yoccoz, N.G. and Ims, R.A.: 'Shedding new light on the diet of Norwegian lemmings : metabarcoding of stomach DNA' (manuscript) 3. Soininen E.M., Ravolainen V.T., Br athen K.A., Yoccoz N.G., Gielly, L. and Ims R.A.: 'Arctic small rodents have diverse diets and exible food preferences' (manuscript) 4. Soininen E.M., Ehrich D., Lecomte N., Yoccoz N.G., Tarroux A., Berteaux D., Gauthier G., Gielly L. and Ims R.A.: 'Sources of variation in small rodent trophic niche : new insights from DNA metabarcoding and stable isotope analysis' (manuscript) 5. Soininen E.M., Br athen, K.A., Jusdado J.G.H, Reidinger S., Hartley S.E.: 'More than herbivory : levels of silica-based plant defences in grasses varies with genotype, species and location', Oikos (2012), Online before print. Available at http://dx.doi.org/10.1111/j.1600-0706.2012.20689.x
URI:	http://hdl.handle.net/10037/4574

File(s) in this item: 2

paper_1.pdf (204.0Kb)

thesis.pdf (9.167Mb)

Antimicrobial natural products from Arctic and sub-Arcticmarine invertebrates

Tadesse, Margey (Doctoral thesis; Doktorgradsavhandling, 17-Sep-2010)

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Abstract:	Infectious diseases are a leading cause of death world-wide and there is a growing need for new anti-infective agents to combat multi-resistant strains of bacteria and fungi. Marine natural products are promising sources of novel antimicrobial compounds. In the present thesis, an investigation into the antimicrobial metabolites of Arctic and sub-Arctic marine invertebrate species is presented. Extracts of seven ascidian species, six sponge species, a soft-alcyonid coral and a bryozoan species, were screened for their antimicrobial activities. The extracts were pre-fractionated by solid phase extraction (SPE) and purified by reversephase high-performance liquid chromatography (RP-HPLC). Active metabolites were characterized by electrospray ionization mass spectrometry (ESI-MS) and nuclear magnetic resonance (NMR) techniques. The antibacterial tyrosine-derived guanidines, 3-dihydroxy-tubastrine and tubastrine, have been isolated from the ascidian Dendrodoa aggregata. This is the first report on the isolation of active metabolites from D. aggregata. 3-dihydroxy-tubastrine has previously been isolated from the Australian sponge species Spongosorites sp. The compound was present in high concentrations in extracts of the ascidian and could serve as a chemotaxonomic marker for the species. Extracts of the ascidian Synoicum pulmonaria displayed the highest antimicrobial activities in our assays. Bio-guided fractionation of the extract, revealed the presence of three novel compounds, named synoxazolidinones A, B and C. The structures of the compounds were elucidated by spectroscopic methods including 1D and 2D NMR techniques, and analysis of mass spectrometric data. The absolute configuration of the compounds was also established by computational methods. The synoxazolidinones contain a unique 4-oxazolidinone core rarely encountered in natural products. Biogenetically, the compounds appear to be derived from arginine and tyrosine. This is the first report on the chemistry of S. pulmonaria. Synoxazolidinones also displayed anticancer activities and provide novel chemical scaffolds for structure-activity relationship studies which are currently being carried out. The dibrominated tryptophan-derived metabolite, eusynstyelamide B, and three new derivatives, eusynstyelamides D, E and F, have been isolated from the bryozoan Tegella cf. spitzbergensis. The structures of the compounds were elucidated by mass spectrometry and, 1D and 2D NMR techniques. All four compounds displayed potent antibacterial activities in our assays. This is the first report of bioactive metabolites from T. spitzbergensis. Eusynstyelamide B has previously been isolated from the Australian ascidian Eusynstyela latericius. The presence of the same metabolites in different organisms and environments, suggests biosynthesis by symbiotic microorganisms. In addition, this thesis provides background information on natural product research and current antimicrobial investigations of marine invertebrate species. The potential of Arctic and sub-Arctic marine invertebrates as sources of structurally novel, bioactive metabolites is demonstrated.
Description:	The papers of the thesis are not available in Munin due to publisher's restrictions: 1. Margey Tadesse, Bjørn Gulliksen, Morten B. Strøm, Olaf B. Styrvold, Tor Haug: «Screening for antibacterial and antifungal activities in marine benthic invertebrates from northern Norway», Journal of Invertebrate Pathology, 99(2008), 286-293 (Elsevier). Available at http://dx.doi.org/10.1016/j.jip.2008.06.009 The accepted version of the article is avalable in Munin at http://hdl.handle.net/10037/2728 2. Margey Tadesse, Veronika Tørfoss, Morten B. Strøm, Espen Hansen, Jeanette Hammer Andersen, Klara Stensvåg, Tor Haug: «Isolation and biological activity of (E)-1-(4-hydroxystyryl)guanidine from the sub-Arctic ascidian, Dendrodoa aggregata», Biochemical Systematics and Ecology (2010) - in press-version (Elsevier). Available at http://dx.doi.org/10.1016/j.bse.2010.04.002 3. Margey Tadesse, Morten B. Strøm, Johan Svenson, Marcel Jaspars, Bruce F. Milne, Veronika Tørfoss, Jeanette H. Andersen, Espen Hansen, Klara Stensvåg and Tor Haug: «Synoxazolidinones A, B, and C; novel bioactive alkaloids from the ascidian Synoicum pulmonaria». Manuscript, published version available in Organic Letters at http://dx.doi.org/10.1021/ol101707u 4. Margey Tadesse, Jioji N. Tabudravu, Marcel Jaspars, Morten B. Strøm, Espen Hansen, Jeanette H. Andersen and Tor Haug: «The antibacterial eusynstelamides B, D, E and F, from the Arctic bryozoan Tegella cf. spitzbergensis» (manuscript)
URI:	http://hdl.handle.net/10037/2702

File(s) in this item: 1

thesis.pdf (960.5Kb)

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

File(s) in this item: 1

thesis.pdf (35.46Mb)

Industriell nyskapning : en undersøkelse av institusjonelle forutsetninger

Trondsen, Torbjørn (Doctoral thesis; Doktorgradsavhandling, May-1985)

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URI: http://hdl.handle.net/10037/3376

File(s) in this item: 1

thesis.pdf (19.38Mb)

Moderators in the relationship between satisfaction and loyalty of Vietnamese fish products consumers

Tuu, Huy Ho (Doctoral thesis; Doktorgradsavhandling, 26-Feb-2011)

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Abstract:	This study first discusses and tests the strength and possible different forms of the relationships between satisfaction and loyalty. Secondly, it focuses on if, and how, satisfaction strength properties (e.g. involvement, ambivalence, knowledge, and certainty) moderate the satisfaction–loyalty relationship. It also extends to discuss and test the role of perceived risk in the satisfaction–loyalty relationship. The empirical foundation for this thesis consists of three surveys and one controlled experiment on the consumption of fish products in Vietnam. The empirical findings rely mainly on multiple regression and structural equation modelling. This thesis shows the satisfaction–loyalty relationship is both linear and non-linear depending on the context and combination of the conceptual facets of satisfaction (e.g. transaction-specific versus cumulative) and loyalty (e.g. intentional versus behavioural). Second, the satisfaction–loyalty relationship is found to be affected by satisfaction strength’s properties such as involvement, ambivalence, knowledge, and certainty in different moderating mechanism. Finally, product risk is found to influence negatively on both satisfaction and loyalty and moderate negatively the satisfaction–loyalty relationship. Thus, marketers should pay more attention to the nonlinear nature of the satisfaction–loyalty relationship to improve the accuracy of predicting loyalty. Marketing strategies, which are directed at educating consumers with relevant knowledge, to consolidate involvement and certainty towards the focal products, and to reduce consumers’ perceived risk and ambivalence, may be the most effective ways to increase repurchase ratings.
Description:	Papers number 1, 2 and 3 are not available in Munin due to publishers' restrictions: 1. Tuu, H. H. and Olsen, S. O: 'Nonlinear effects between satisfaction and loyalty: An empirical study of different conceptual relationships', Journal of Targeting, Measurement and Analysis for Marketing, 18, 239–251 (Macmillian). Available at http://dx.doi.org/10.1057/jt.2010.19 2. Tuu, H. H. and Olsen, S. O.: 'Ambivalence and involvement in the satisfaction–repurchase loyalty relationship', 2010, Australasian Marketing Journal, 18, 151–158 (Monash University). Available at http://dx.doi.org/10.1016/j.ausmj.2010.03.002 3. Tuu, H. H. and Olsen, S. O.: 'Food risk and knowledge in the satisfaction–repurchase loyalty relationship', 2009, Asia Pacific Journal of Marketing and Logistics, 21(4), 521–536 (Emerald). Available at http://dx.doi.org/10.1108/13555850910997571
URI:	http://hdl.handle.net/10037/2971

File(s) in this item: 3

paper_4.pdf (190.2Kb)

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På grensen til et eventyr : økonomisering av Snøhvit LNG

Tveiterås, Kathrine (Doctoral thesis; Doktorgradsavhandling, 29-Jun-2012)

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Abstract:

Megaprosjekter er store investeringsprosjekter med betydelig innflytelse på samfunn, miljø og økonomi. Til tross for grundige utredninger og beregninger i forkant, presterer slike prosjekter sjelden i overenstemmelse med planene: de blir gjerne både forsinket og mye dyrere enn estimatene tilsa. Hva er det som skjer i megaprosjekter som gjør at planer om suksess blir til fortellinger om fiasko? Dette spørsmålet har fått stor oppmerksomhet både i offentlige institusjoner, i media og i faglitteraturen. De skisserte løsningene for å endre på den klassiske utviklingen har ofte dreiet seg om å forbedre bruken av styringsverktøy, med sterkere krav til nøyaktighet i beregninger og gjennomsiktighet i beslutningsprosessene. Denne avhandlingen problematiserer slike resepter, og argumenterer for at fokuset på mer nøyaktighet i megaprosjekter samtidig overser hvilken innvirkning dette kravet i seg selv har på hvordan prosjektene presterer. Studien flytter på denne måten fokuset fra bruken av styringsverktøy til verktøyene selv. Hva er deres rolle i megaprosjektenes dynamikk? Avhandlingen tar for seg utbyggingen av Snøhvit LNG. Prosjektet ble gjennomført i 2002-2007, mer enn 20 år etter at funnene ble gjort i Hammerfestbassenget. Den lange tiden skyldtes at var et nytt og usikkert prosjekt, og det var derfor vanskelig å finne en utbyggingsløsning som ble ansett både som gjennomførbar og lønnsom. Til slutt lyktes arbeidet med dette og Snøhvit ble realisert. Men til tross for omfattende forberedelser sluttet prosjektet seg likevel raskt til rekken av megaprosjekter som ikke presterer som forutsatt, med både forsinkelser og store kostnadsoverskridelser. Det ble anvendt en rekke styringsredskaper for å manøvrere i prosjektets usikre og komplekse omgivelser. Disse verktøyene baserer seg på økonomiske prinsipper: Oppfatningen er at tallene vil gi nøytrale svar. Avhandlingen anvender et STS-perspektiv og studerer bruken av to slike styringsredskaper i prosjektet. Først handler det om hvordan Snøhvit ble konstruert som et lønnsomt prosjekt. Det sentrale verktøyet for å vurdere dette er nettonåverdimodellen. Deretter handler det om hvordan kostnadsoverskridelsene ble håndtert. Det er inntjent verdistyring som hjelper til med dette. Ved å bruke disse instrumentene, kunne prosjektet tilpasses kalkylenes logikk. Dette kalles økonomisering. Ved å oversette usikre momenter til tall, blir kompleks informasjon mulig å sammenligne, håndtere og ta stilling til. Uten denne forenklingen er det vanskelig å ta beslutninger. Det er imidlertid den samme forenklingen som skaper problemer i gjennomføringen fordi de ikke favner kompleksiteten i utbyggingen. Studien gir nye innspill til megaprosjektforskningen. Det er ikke bare menneskelige aktører som spiller en rolle; hvordan prosjektverktøyene virker sier også noe om sammenhengen og dynamikken i et stort prosjekt. Jo mer nøyaktig omgivelsene tallfestes, jo mer sannsynlig er det at ting vil utvikle seg annerledes. Det kan således synes som at det nødvendige valget for megaprosjekter er et kostnadsoverskridende prosjekt eller ingen prosjekt over hode. En aksept for dette innebærer at framtidige forsknings- og samfunnsspørsmål bør stilles på en måte som er mer relevant for dynamikken i megaprosjekter. Hvilken type kunnskap er nødvendig for styring og evaluering av prosjekter, og hvilken type kunnskap koster mer enn den gir fordeler?

URI:

http://hdl.handle.net/10037/4299

File(s) in this item: 1

thesis.pdf (1.237Mb)

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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paper_4.pdf (728.0Kb)

thesis.pdf (1.331Mb)

Måling av produktivitet : en sammenligning av ulike metoder, med spesiell vekt på Data Envelopment Analysis

Vassdal, Terje (Doctoral thesis; Doktorgradsavhandling, Sep-1988)

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URI: http://hdl.handle.net/10037/3362

File(s) in this item: 1

thesis.pdf (15.83Mb)

Post mortem proteolytic degradation of myosin heavy chain in skeletal muscle of Atlantic cod

Wang, Pål Anders (Doctoral thesis; Doktorgradsavhandling, 28-Jan-2011)

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Abstract:	One of the most important parameters of quality regarding meat both from mammals and fish is texture. The post mortem degradation of muscle and connective tissue proteins during tenderization of meat from warm-blooded animals is unwanted in fish due to a loss of product quality. Soft fillet and gaping are common problems both in wild and farmed cod and have huge impact on the quality and the consumers’ perception of the products. The underlying mechanisms responsible for the changes in texture are not known, but endogenous proteolytic enzymes seem to play an important role in the process. A muscle cell contains several proteolytic systems. Among these are the multicatalytic proteasome, lysosomal cathepsins, cytosolic calpains and metalloproteinases. It has been shown that calpains are important in the degradation process resulting in tender meat in warm-blooded animals. In fish, the calpains and cathepsins have been suggested to act in cooperation resulting in the observed post mortem degradation of muscle proteins. Many of the cathepsins and calpains have been shown to be able to degrade myofibrillar proteins in vitro systems. Such systems have traditionally been a main strategy when studying protein degradation post slaughter in fish muscle. A weakness in such systems is that grinding of muscle tissue and isolation of proteins from the homogenate leads to a loss of the internal control system in the muscle. Another problem by using such systems is that the conditions are often highly optimized and therefore very different from normal post mortem muscle. The temperature and pH is often different from normal post mortem muscle. In this thesis cathepsin D, one of the candidate enzymes being responsible for post mortem muscle degradation in cod has been studied. The enzyme was purified from cod liver, and an antibody specific against the enzyme was produced in mouse. The isolated enzyme had lower tolerance towards temperature than a similar commercial available enzyme isolated from bovine. The antibody detected cathepsin D in extracts from several other fish species. Further, the degradation of myosin heavy chain (MHC) was studied. The degradation of MHC in isolated myofibrils occurred at the highest rate at high temperature (20ºC) and low pH (5.5), but degradation occurred even when stored on ice and at relevant muscle-pH. For comparison, intact muscle was stored prior to isolation of myofibrils. The results showed that the MHCdegradation occurred in a similar pattern in intact muscle, however less prominent. It was also shown that cathepsin D was associated with the myofibrils, and the enzyme could not be completely removed even after several washing steps. A model system was established, that made it possible to study how small changes in pH and inhibitors of proteolytic enzymes influence on the MHC-degradation in intact muscle tissue post slaughter. A low muscle-pH (6.05-6.3) did lead to degradation of MHC, while the protein stayed unchanged at pH 6.9. Inhibitors of cysteine and aspartic acid proteinases were obviously more efficient in preventing MHC-degradation than inhibitors of serine and metalloproteinases. A surprising observation was that EDTA, an inhibitor of metalloproteinases, increased the degradation of MHC. The conlusion of this thesis is that lysosomal cathepsins of the cysteine- and aspartic acid-types are responsible for the MHC-degradation in intact muscle. The new model system will be suitable when studying how other muscle proteins are degraded in intact muscle tissue post slaughter, and which enzymes that are involved.
Description:	The papers in this thesis are not available due to publishers' restrictions: 1. Wang, P.A, Steinvik, J., Larsen, R., Mæhre, H and Olsen, R.L.:'Cathepsin D from Atlantic cod (Gadus morhua L.) liver. Isolation and comparative studies', Comparative Biochemistry and Physiology, Part B (2007), 147, 504–511. Available at http://dx.doi.org/10.1016/j.cbpb.2007.03.004 2. Wang, P.A., Martinez, I. and Olsen, R.L.:'Myosin heavy chain degradation during post mortem storage of Atlantic cod (Gadus morhua L.)', Food Chemistry (2009), 115, 1228–1233. Available at http://dx.doi.org/10.1016/j.foodchem.2009.01.031 3. Wang, P.A., Vang, B., Pedersen, A.M., Martinez, I. and Olsen R.L.: 'Postmortem degradation of myosin heavy chain in intact fish muscle: Effects of pH and enzyme inhibitors', Food Chemistry (2011), 124, 1090–1095. Available at http://dx.doi.org/10.1016/j.foodchem.2010.07.093
URI:	http://hdl.handle.net/10037/3337

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Arctic charr (Salvelinus alpinus (L.)), an adequate host to Gyrodactylus salaris (Monogenea)

Winger, Anja Celine (Doctoral thesis; Doktorgradsavhandling, 26-May-2009)

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Abstract:	Arctic charr is a suitable host to Gyrodactylus salaris, and G. salaris is a non-pathogen to this host species. This parasite is highly pathogenic to Norwegian Atlantic salmon and it has driven most affected salmon populations to extinction. In Troms County in northern Norway, two rivers are infected. These two rivers, Skibotnelva and Signaldalselva, are the northernmost G. salaris infected rivers in Norway and the natural salmon populations are regarded extinct or close to extinction due to the parasite. Skibotnelva has been treated twice with the plant poison rotenone. Both treatments failed, and an ongoing hypothesis is that the occurrence of Arctic charr is the main cause of this. The overall aim of this study was to elucidate the role of Arctic charr as a long-term host to G. salaris. Both field and experimental studies have been undertaken. It was found that the abundance of G. salaris varies significantly throughout the year in both Skibotnelva and Signaldalselva, and is highest in the autumn and lowest in the spring. These seasonal fluctuations were repeated between years, and are mainly explained as temperature dependent constraints upon parasite reproduction in combination with host immune responses. Further, it was documented that Arctic charr in allopatry can sustain a G. salaris population during the five winter months, and also that newly hatched charr fry are highly susceptible to the parasite. The newly hatched charr fry experienced additive parasite induced mortality. Furthermore, experimental studies indicated that parasite transmission occurs frequently within the charr fry population at all times during the colonization process. Hence, transmission probably is an important process in determining the infrapopulation structure by reducing the over-dispersion of G. salaris between hosts, and also may contribute to a prolonged period of growth of the parasite metapopulation. In conclusion, this study clearly indicates that Arctic charr has to be valued as an important and adequate host to G. salaris which can sustain the parasite population within watercourses independent of the presence of infected salmon.
Description:	The papers of the thesis are not available in Munin: 1. Anja C. Winger, Marte Kanck, Roar Kristoffersen and Rune Knudsen: «Seasonal dynamics and persistence of Gyrodactylus salaris in two riverine anadromous Arctic charr populations», Enviromnetal biology of fishes, 2008,83,117-123 (Springer; publisher's restrictions), available at http://dx.doi.org/10.1007/s10641-007-9274-x 2. A. C. Winger, R. Kristoffersen, S. I. Siikavuopio and R. Knudsen: «Experiments to test if allopatric Salvelinus alpinus are suitable year-round hosts of Gyrodactylus salaris (Monogenea)», Journal of Fish Biology (2009) 74, 1476–1486 (Wiley-Blackwell; publisher's restrictions), available at http://dx.doi.org/10.1111/j.1095-8649.2009.02215.x 3. A. C. Winger, R. Primicerio, R. Kristoffersen, S. I. Siikavuopio and R. Knudsen: «Gyrodactylus salaris infecting allopatric Arctic charr Salvelinus alpinus fry: an experimental study of host survival», Journal of Fish Biology (2008) 73, 2198–2209 (Wiley-Blackwell; publisher's restrictions), available at http://dx.doi.org/10.1111/j.1095-8649.2008.02056.x 4. A. C. Winger, R. Knudsen, R. Primicerio and R. Kristoffersen: «Infrapopulation dynamics and the role of transmission in the hyperviviparous Gyrodactylus salaris (Monogenea)» (manuscript)
URI:	http://hdl.handle.net/10037/2581

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Calanus glacialis : the role of lipids in the life cycle and for the Arctic pelagic food web

Wold, Anette (Doctoral thesis; Doktorgradsavhandling, 23-May-2012)

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Abstract:	The Arctic marine ecosystem is characterized by strong seasonality and a short but productive period of primary production in the spring when the ice breaks up. Calanus glacialis is one of the key links between primary producers and higher trophic levels, and it is adapted to the strong seasonality by life cycle traits such as; seasonal vertical migration, diapausing, reproduction in the spring and extensive energy storage. The timing of these events will have consequences for the success of C. glacialis and also for the energy available at higher trophic levels. The aim of this study was to increase the knowledge about these key life history traits with focus on the role of lipid accumulation, seasonal vertical migration and the transfer of energy from primary producers through Calanus, to higher trophic levels, such as seabirds and seals. Lipid accumulation and seasonal vertical migration of C. glacialis were studied in the Amundsen Gulf, in the Canadian Arctic (Paper I) and in Svalbard waters (Paper II and III). The transfer of energy to higher trophic levels was studied by comparing the fatty acid composition of predators to that of their prey and by using stable isotope analysis to calculate their trophic level. We analyzed five seabird species from Kongsfjorden; Little auk (Alle alle), Brünnich’s guillemot (Uria lomvia), Black-legged kittiwake (Rissa tridactyla), Northern fulmar (Fulmarus glacialis) and Glaucous gull (Larus hyperboreus) (Paper IV) as well as harp seals (Phoca groenlandica) and hooded seals (Cystophora cristata) from the West Ice (Paper V). The timing of the ascent of C. glacialis during spring, the match of reproduction with the primary production as well as the length of the primary production period determines the development of offspring , the overwintering stage the following winter, and hence the length of the life cycle. The shorter the period of primary production, the more important is the match between reproduction and bloom. Ice algae may fuel early maturation of the females and prolong the reproductive period. In the Amundsen Gulf, C. glacialis ascended to the surface water in time to feed on the ice algae bloom, but since CIII was the main overwintering stage, the ice algae fuelled development of CIII which could develop to females that possibly could spawn during the summer. The life history trait of accumulating energy in form of lipids is an adaptation of Calanus to the large seasonal and inter-annual fluctuations in food availability, and the lipids represent an effective transfer of energy up the food chain. High levels of the Calanus markers 20:1n9 and 22:1n11 in the seabirds Little auk, Black-legged kittiwake and Northern fulmar from Kongsfjorden, Svalbard, indicate that these seabirds are part of the Calanus based food web (Paper IV). Harp seals and hooded seals (Paper V) showed considerably overlap in diet, but the fatty acid composition of harp seals originated from a diatom–Calanus based food web, while the fatty acids of hooded seals originated from a food web based on dinoflagellates and the prymnosiophyte Phaeocystis pouchetii. To conclude, the diatom–Calanus food chain is an important driver for the high latitude pelagic arctic food web. The match between timing of primary production, either as ice algae or phytoplankton bloom, and the timing of reproduction of C. glacialis is crucial for the accumulation of lipids in Calanus may have consequences for the energy available for higher trophic levels.
Description:	Papers 1,3,4 and 5 of this thesis are not available in Munin: 1. Wold A, Darnis G, Søreide JE, Leu E, Philippe B, Fortier L, Poulin M, Kattner G, Graeve M and Falk-Petersen S: 'Life strategy and diet of Calanus glacialis during the winterspring transition in Amundsen Gulf, southeastern Beaufort Sea' Polar Biology (2011) 34:1929-1946. Available at http://dx.doi.org/10.1007/s00300-011-1062-6 3. Wold A, Leu E, Walkusz W and Falk-Petersen S: 'Lipids in copepodite stages of Calanus glacialis', Polar Biology (2007) 30:655-658. Available at http://dx.doi.org/10.1007/s00300-006-0233-3 4. Wold A, Jæger I, Hop H, Geir Wing Gabrielsen GW and Falk-Petersen S: 'Arctic seabird food chains explored by fatty acid composition and stable isotopes in Kongsfjorden, Svalbard', Polar Biology (2011) 34:1147-1155. Available at http://dx.doi.org/10.1007/s00300-011-0975-4 5. Falk-Petersen S, Haug T, Hop H, Nilssen KT and Wold A: 'Transfer of lipids from plankton to blubber of harp and hooded seals off East Greenland', Deep-Sea Research II (2009) 56:2080-2086. Available at http://dx.doi.org/10.1016/j.dsr2.2008.11.020
URI:	http://hdl.handle.net/10037/4152

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