Munin: Browsing Doktorgradsavhandlinger (BFE-fak) by Issue Date

Industriell nyskapning : en undersøkelse av institusjonelle forutsetninger

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

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Dendroclimatology on Scots pine (Pinus sylvestris L.) in northern Norway

Kirchhefer, Andreas Joachim (Doctoral thesis; Doktorgradsavhandling, 17-Mar-2000)

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Abstract:

A total of ten tree-ring chronologies of Scots pine, Pinus sylvestris L., was constructed between the Vesterålen archipelago and the Finnmarksvidda in order to investigate the regional variability of radial growth and climate response of pine. The longest tree-ring chronology, located in Forfjorddalen in Vesterålen, was highly significant back to AD 1354. The study area was divided into three dendroecological zones; the coast, the inner Scandes and the Finnmarksvidda. In all regions, July temperature was the most important growth-determining factor. At the coast, pine showed a significant positive response also to August temperatures. A partial study in the inner Scandes showed that the radial growth at north-facing slopes was enhanced by high June temperatures, most likely due to the influence of the midnight sun. Evidence of environmental stress due to global warming was seen in reduced growth during periods of warm-moist mid winters at the coast and, particularly in the warm 1930s, in the Scandes. Also, there were indications of drought stress in summer in the intra-alpine valleys of the Scandes and at the edaphically dry coastal site, Stonglandseidet.
On the basis of the tree-ring chronologies, July temperatures were reconstructed back to AD 1800 for northern Norway 69°N and July-August temperatures along the coast back to AD 1358. The 20th century since 1915 was a period of above-average temperatures and growth. In the present reconstruction, a comparable warm period occurred previously only AD 1470-1540. In the 19th century, cool summers prevailed about AD 1810, in the 1830s and from the late 1860s to 1910. The 17th century, the coolest interval of the ‘Little Ice Age’, experienced three intervals of cool summers around AD 1605, 1640 and 1680. There was evidence of a lack of pine regeneration in the first half of the 17th century. Major regional temperature differences were observed around AD 1760 with extraordinarily warm summers east of the Scandes, but average temperatures at the coast, and about AD 1800, when the coast was warm, but the inland cooling. An exploratory reconstruction of June temperatures from growth differences between northand south-facing slopes demonstrated the potential of site-related growth responses for refined climate reconstructions.

URI:

http://hdl.handle.net/10037/2412

File(s) in this item: 5

paper_1.pdf (257.1Kb)

paper_2.pdf (278.7Kb)

paper_3.pdf (242.4Kb)

thesis_entire.pdf (1.540Mb)

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

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

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Abstract:

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

URI:

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

File(s) in this item: 1

thesis.pdf (1.911Mb)

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

Jørgensen, Roar (Doctoral thesis; Doktorgradsavhandling, 2004)

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

File(s) in this item: 2

paper_4.pdf (489.2Kb)

thesis.pdf (691.1Kb)

Quality of salted cod (Gadus morhua L.) as influenced by raw material and salt composition

Lauritzsen, Kristin (Doctoral thesis; Doktorgradsavhandling, 29-Mar-2004)

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Abstract:

Hva påvirker kvaliteten på saltfisk? Saltfiskens lukt, farge, konsistens og smak bestemmer kvaliteten. Dersom torsken blir dødsstiv samtidig med at saltet strømmer inn i fiskekjøttet, oppnår man et lavere vektutbytte, vann- og saltinnhold på sluttproduktet. Fisken bør derfor saltes etter dødsstivheten for å oppnå et høyt vektutbytte. Ønsker man å minimere proteintapet fra salteprosessen og få en høy lyshet på sluttproduktet, bør fisken derimot saltes før dødsstivheten inntrer. Økt kalsium- og magnesiuminnhold samt lav pH i saltet, gir et hvitere og mer fast ferdigprodukt samt et lavere proteintap fra prosessen. Torskefilet har et høyt innhold av flerumettede fettsyrer, og er derfor spesielt utsatt for harskning og fargeendringer ved salting. Det er påvist at torskens muskel-pH (surhet) etter slakting, har betydning for evnen til å motvirke misfarging av ferdigproduktet i nærvær av kopper. Lav muskel-pH ga større misfarging samt lavere vanninnhold i fullsaltet muskel enn høy muskel-pH før salting. Kopper og jern er metaller som naturlig forekommer i fiskekjøtt, salt og drikkevann. Kopper-ioner framskynder harskning i fullsaltet torsk og gir kraftigere gul misfarging av ferdigproduktet sammenlignet med jern. Enverdig kopper er mer harskningsfremmende enn toverdig kopper. For å unngå harskning, er det vanlig å bruke antioksidanter i framstillingsprosessen. Når mer enn 0.1% natriumaskorbat blir tilsatt saltlaken, forhindrer den kopper i å fremme harskning av torskemuskelen. Antioksidantene sitronsyre og EDTA ble også undersøkt, men kun ved lav konsentrasjon sammen med kopper i saltlaken. EDTA var en effektiv antioksidant, mens sitronsyre derimot fremmet harskning i fullsaltet torsk. Doktorgradsarbeidet ble finansiert av næringsmiddelprogrammet ved Norges forskningsråd i perioden 1997-2001.

URI:

http://hdl.handle.net/10037/1819

File(s) in this item: 6

paper_1.pdf (3.960Mb)

paper_2.pdf (544.1Kb)

paper_3.pdf (667.7Kb)

paper_4.pdf (866.8Kb)

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

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

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Abstract:

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

URI:

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

File(s) in this item: 6

paper_1.pdf (59.88Kb)

paper_2.pdf (245.8Kb)

paper_3.pdf (241.0Kb)

paper_4.pdf (239.4Kb)

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Effect of viral RNA mimics and ISA virus infection on expression of key genes of the Atlantic salmon interferon system

Kileng, Øyvind (Doctoral thesis; Doktorgradsavhandling, 2008)

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Abstract:	We have studied the innate immune responses of Atlantic salmon and how this responds to stimulation and infection by the aquatic orthomyxovirus Infectious salmon anemia virus (ISAV). This work has focused on the Type I interferon (IFN) system which is critically important in the vertebrate immune response against viral infections. As a part of this work we have studied the Atlantic salmon IFN regulatory factor 7 (IRF7). In mammals IRF7 is the major regulator of IFN transcription in response to viral infections, and our results show that the salmon homolog performs similar tasks. Furthermore, we have investigated the stimulatory effect of two synthetic ligands that induce the IFN system by mimicking viral infections in the cell and compared this to the immune response against ISAV. Our results indicate that both specialized immune cells and non-immune cells induce the IFN system in response to these treatments, but we also show that ISAV is able to interfere with the host` IFN response in order to successfully replicate. Finally, our studies show that the ISAV genome encodes two genes, S7ORF1 and S8ORF2, which is involved in antagonizing the IFN response during infections.
Description:	The papers of the thesis are not available in Munin: 1. Kileng, Ø., Brundtland, M. I. and Robertsen, B.: «Infectious salmon anemia virus is a powerful inducer of key genes of the type I interferon system of Atlantic salmon, but is not inhibited by interferon», Fish & Shellfish immunology 23(2007); 378-389 (Elsevier - publisher's restriction). Available at http://dx.doi.org/10.1016/j.fsi.2006.11.011 2. Kileng, Ø., Albuquerque, A. and Robertsen, B.: «Induction of interferon system genes in Atlantic salmon by the imidazoquinoline S-27609, a ligand for Toll-like receptor 7», Fish & Shellfish immunology 24(2007); 514-522 (Elsevier - publisher's restriction). Available at http://dx.doi.org/10.1016/j.fsi.2007.10.005 3. García-Rosado, E., Markussen, T., Kileng, Ø., Baekkevold, E. S., Robertsen, B., Mjaaland, S. and Rimstad, E.: «Molecular and functional characterization of two infectious salmon anaemia virus (ISAV) proteins with type I interferon antagonizing activity», Virus Research 133(2008); 228-238 (Elsevier - publisher's restriction). Available at http://dx.doi.org/10.1016/j.virusres.2008.01.008 4. Kileng, Ø., Workenhe, S. T., Bergan, V. and Robertsen, B.: «An Atlantic salmon IRF-7 gene identified by analysis of sequence and function and its expression compared with a STAT1 gene». Manuscript, later published in Developmental and Comparative Immunology 33(2009); 18-27 (Elsevier), published version available at http://dx.doi.org/10.1016/j.dci.2008.07.020
URI:	http://hdl.handle.net/10037/2467

File(s) in this item: 1

thesis.pdf (1.473Mb)

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)

Boundary construction in mandated science : the case of ICES' advice on fisheries management

Nolde Nielsen, Kåre (Doctoral thesis; Doktorgradsavhandling, 21-Nov-2008)

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Abstract:	What is the relationship between science and politics? What should it be? How are their respective roles conceived and acted out in practice? Should science and politics be clearly separated? How? Are there cases in which they can be usefully mixed? What cases are those, and are there some ways of mixing that are better than others? This project explores such questions by examining relationships between ICES fisheries advice and decision-making in fisheries management. While traditional conceptions portray science as a rather autonomous entity, this case examines a context in which such conceptions are particularly prone to be challenged. First, scientific advice that forms direct inputs into policy-making is better characterized as ‘research’ or ‘mode-2 science’ than as autonomous science. Second, advisory science on fisheries management is ‘post-normal’ insofar as its knowledge claims are uncertain, values disputed and decisions urgent. Here, fact and values easily become entangled, which in turn challenges conceptions of autonomous science. How is the science-politics boundary constructed here? Since ICES advice constitutes the formal and highly important link between science and politics in fisheries, it offers a concrete location for studying boundary dynamics. Although this project mainly mobilizes Science and Technology Studies theory (in particular Actor Network Theory) it not only seeks to contribute to this literature, but considers how insights generated from such perspectives may contribute to the ongoing discourses on fisheries science and management. The thesis demonstrates that a comprehensive understanding of the construction, maintenance and transgression of the boundary between fisheries advisory science and management cannot be limited to studies of ‘boundary work’ as discursive practices; it also requires examinations of practices in scientific knowledge production, the material embodiment of this knowledge, its use in policy-making, and conditions on which its stability depends. Forms of uncertainty in ICES fisheries advice are explored and are demonstrated to challenge conceptions of a clear-cut science-politics boundary. The thesis proposes ways in which the science and politics of fisheries can be reconsidered by the development of a framework for enabling evaluations of fisheries management systems. This is expected to enhance communication across disciplines concerned with fisheries management, and to promote systemic learning.
Description:	The author received the Fishery Research Award (Fiskeriforskningsprisen) at the University of Tromsø 2009, for this doctoral thesis. The papers of the thesis are not available in Munin (mainly) due to publishers' restrictions: 1. Nielsen, Kåre Nolde, and Petter Holm: 'The TAC Machine: On the Institutionalization of Sustainable Fisheries Resource Management' (manuscript) 2. Nielsen, Kåre Nolde and Petter Holm (2007): 'A brief catalogue of failures: Framing evaluation and learning in fisheries resource management', Marine Policy 31: 669-680 (Elevier - publisher's restrictions). Available at http://dx.doi.org/10.1016/j.marpol.2007.03.014 3. Schwach, V., D. Bailly, A.-S. Christensen, A. Delaney, P. Degnbol, W. van Densen, P. Holm, H.A. McLay, K.N. Nielsen, M.A. Pastoors, S.A. Reeves, and D.C. Wilson (2007): 'Policy and knowledge in fisheries management: a policy brief', ICES Journal of Marine Science 64: 798-803 (Oxford University Press - publisher's restrictions). Available at http://dx.doi.org/10.1093/icesjms/fsm020 4. Nielsen, Kåre Nolde: 'Risking Precaution: Framing Uncertainty in Fisheries Advice' (manuscript) 5. Hauge, K.H., K.N. Nielsen, and K. Korsbrekke (2007): 'Limits to transparency— exploring conceptual and operational aspects of the ICES framework for providing precautionary fisheries management advice', ICES Journal of Marine Science 64: 738-743 (Oxford University Press - publisher's restrictions). Available at http://dx.doi.org/10.1093/icesjms/fsm058 6. Holm, Petter and Kåre Nielsen (2007): 'Framing fish, making markets: the construction of Individual Transferable Quotas (ITQs)’, in 'Market Devices' edited by Michel Callon, Yuval Millo and Fabian Muniesa (Blackwell - publisher's restrictions). Check availability
URI:	http://hdl.handle.net/10037/2401

File(s) in this item: 1

thesis.pdf (1.139Mb)

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)

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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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

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