Blar i tittel Fakultet for biovitenskap, fiskeri og økonomi

Viser treff 1176-1195 av 5087

    • Ecological speciation in European whitefish is driven by a large‐gaped predator 

      Öhlund, Gunnar; Bodin, Mats; Nilsson, Karin; Öhlund, Sven-Ola; Mobley, Kenyon B.; Hudson, Alan G.; Peedu, Mikael; Brännström, Åke; Bartels, Pia; Præbel, Kim; Hein, Catherine L.; Johansson, Petter; Englund, Göran (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-13)
      Lake‐dwelling fish that form species pairs/flocks characterized by body size divergence are important model systems for speciation research. Although several sources of divergent selection have been identified in these systems, their importance for driving the speciation process remains elusive. A major problem is that in retrospect, we cannot distinguish selection pressures that initiated divergence ...

    • Ecological speciation in postglacial European whitefish: rapid adaptive radiations into the littoral, pelagic, and profundal lake habitats 

      Præbel, Kim; Knudsen, Rune; Siwertsson, Anna; Karhunen, Markku; Kahilainen, Kimmo K.; Ovaskainen, Otso; Østbye, Kjartan; Peruzzi, Stefano; Fevolden, Svein-Erik; Amundsen, Per-Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2013)
      Understanding how a monophyletic lineage of a species diverges into several adaptive forms has received increased attention in recent years, but the underlying mechanisms in this process are still under debate. Postglacial fishes are excellent model organisms for exploring this process, especially the initial stages of ecological speciation, as postglacial lakes represent replicated discrete ...

    • Ecological stoichiometry and nutrient partitioning in two insect herbivores responsible for large-scale forest disturbance in the Fennoscandian subarctic 

      Metcalfe, Daniel B.; Cherif, Mehdi; Jepsen, Jane Uhd; Vindstad, Ole Petter Laksforsmo; Kristensen, Jeppe Å.; Belsing, Ulrika (Journal article; Tidsskriftartikkel; Peer reviewed, 2018-10-04)
      <p>1. Outbreaks of herbivorous insects can have large impacts on regional soil carbon (C) storage and nutrient cycling. In northernmost Europe, population outbreaks of several geometrid moth species regularly cause large‐scale defoliation in subarctic birch forests. An improved understanding is required of how leaf C and nutrients are processed after ingestion by herbivores and what this means for ...

    • Ecology of a tropical bay and the social aspects of small-scale fisheries: Implications for management 

      Andrade Rodriguez, Hector Antonio (Doctoral thesis; Doktorgradsavhandling, 2015-09-02)

    • Econometrics versus the Bookmakers. An econometric approach to sports betting 

      Hansen, Sindre Michael (Master thesis; Mastergradsoppgave, 2016-06-01)
      Bruk av økonometri for å estimere sannsynligheter for ulike utfall i fotballkamper, over en Premier League sesong. Lager en modell basert på Bradley-Terry. Resultatet av estimeringene testes deretter ved å sammenligne med historisk odds satt av ulike spilltilbydere, og anvendes for hypotetiske innsatser. Modellen viser profitt.

    • Economic analyses of user interactions in the coastal zone 

      Mikkelsen, Eirik (Doctoral thesis; Doktorgradsavhandling, 2008-05-05)
      Marine and coastal areas contain many resource types, with many uses and user groups. Conflicts are common, both over access to the same resource, and to avoid negative effects of others’ use. Such conflicts are expected to increase in extent and severity. Being able to analyze and understand the nature and consequences of the interactions between different user groups, how it affects their behaviour ...

    • Economic analysis of Marine Protected Areas: Bioeconomic Modeling and Economic Valuation Approaches 

      Bui, Bich Xuan (Doctoral thesis; Doktorgradsavhandling, 2017-04-05)
      Marine protected areas (MPAs) are often established for conservation objectives. Benefits provided by MPAs exceed pure biodiversity conservation as they may include contributions to social and economic benefits of local communities. And though it is still debated, MPAs may provide a management tool for sustainable fisheries and/or solving conflicts of interests between users of marine resources. It ...

    • Economic analysis of rural and artisanal aquaculture in Ecuador 

      Recalde Ruiz, Jose Renato (Master thesis; Mastergradsoppgave, 2009-05-15)
      Three different types of culture and conditions were tested to determine the profitability of Rural and Artisanal Aquaculture Project in Ecuador: monoculture of the freshwater fish named locally cachama (Piaractus brachypomus), monoculture of red claw crayfish (Cherax quadricarinatus) and polyculture tilapia (Oreochromis sp.) – cachama (Piaractus brachypomus). The economic models used for this ...

    • Economic analysis of the environmental impact on marine cage lobster aquaculture in Vietnam 

      Ly, Nguyen Thi Y (Master thesis; Mastergradsoppgave, 2009-05-15)
      In Vietnam, marine cage lobster aquaculture has been expanding significantly over the last years. Besides the economic contribution for locals living in the coastal areas in Central of Vietnam, this industry has created some problems that are relating to the marine environmental protection where trash fish feed is predominant. This paper investigates the environmental impact on cage marine lobster ...

    • The economic determinants of tourism seasonality: A case study of the Norwegian tourism industry 

      Xie, Jinghua (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-02-26)
      Since seasonality has long been recognized as one of the most critical problems in the tourism industry, many studies have been conducted to investigate its reasons. Nevertheless, almost all the studies focus on climate and institutional reasons, ignoring the possible economic determinants. In this study, we use econometric models to estimate how economic factors such as tourist’s income, the relative ...

    • The economic development of the kapenta fishery Lake Kariba (Zimbabwe/Zambia) 

      Madamombe, Loveness (Master thesis; Mastergradsoppgave, 2002-06-07)
      Kapenta (Limnothrissa miodon) was introduced from Lake Tanganyika into the man-made Lake Kariba, where it now supports a large and viable fishery for Zimbabwe and Zambia who share the lake. The challenge for this paper has been to investigate whether the viability of the kapenta fishery is dependent upon biological factor or economic parameters. The Pella and Tomlinson surplus production model ...

    • Economic drivers for the Chinese tourists 

      Xie, Jinghua; Tveterås, Sigbjørn Landazuri (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-02)
      Asia, particularly China, has become an attractive market that receives much attention in the Norwegian tourism industry. This raises relevant questions about the sustainability of the Chinese tourism boom. If the Norwegian tourism industry increasingly targets this rapidly growing market with larger investments, it should respond to the prospects of long-term growth. Such prospects hinge on the ...

    • The economic efficiency of a trawl fishery in Nha Trang, Khanh Hoa province, Vietnam 

      Tran, Van Hao (Master thesis; Mastergradsoppgave, 2012-05-15)
      Vietnamese fisheries have long traditional development. They are operating under an open access fisheries regime with small scale, multi-species and multi-fishing gears. The number of fishing vessels, the total engine power and the total yield have been increasing continuously overtime; meanwhile the CPUE (catch per unit effort) have been reducing seriously. Vietnamese fisheries are facing ...

    • Economic Impacts of Global Warming : The Case of the Barents Sea Fisheries 

      Eide, Arne (Journal article; Tidsskriftartikkel; Peer reviewed, 2007)
      Regional analyses of possible physical and biological effects of global warming in the Barents Sea area have been carried out recently. Based on such studies possible economic impacts of global warming on the Barents Sea fisheries have been quantified, assuming different types of management regimes. The EconSimp2000 model, consisting of the ecosystem model AggMult and the fleet model EconMult have ...

    • Economic incentives in outpatient care and patient demand for pharmaceuticals. A study of antibiotics and addictive drugs prescriptions 

      Zykova, Yana (Doctoral thesis; Doktorgradsavhandling, 2021-12-07)
      The questions asked in this thesis relate to the economic incentives and characteristics of the health care market, which may result in suboptimal drug prescription. We consider two types of pharmaceuticals, such as antibiotics and addictive drugs. These pharmaceuticals are interesting because their use/misuse is associated with costs both at the individual and societal levels. The decision about ...

    • Economic performance and capacity utilisation in vietnamese purse seine fishery 

      Cao, Thi Hong Nga; Eide, Arne; Armstrong, Claire W.; Long, Le Kim (Journal article; Tidsskriftartikkel; Peer reviewed, 2020)
      This study identifies differences in vessel efficiency amongst purse seiners in Vietnamese fishery. Deterministic data envelopment analysis (DEA) was used to assess relative capacity utilisation of each vessel, and double bootstrap DEA was adopted to overcome some of the drawbacks of nonparametric DEA. The study was based on a survey of costs and earnings from 52 purse seiners in 2016, revealing ...

    • Economic performance and productivity of the small pelagic fleet in Southern Angola. A comparative study between the fleets in Benguela and Namibe fishing towns 

      Chilamba, Victor Capapelo Julio (Master thesis; Mastergradsoppgave, 2016-05-18)
      The study contains operational and economic information regarding the SPF in Benguela and Namibe fishing towns, for 2014. The 28 distinct purse-seiners represent 48% of the fleet population and contribute with about 54% of landings. Most vessels vary with respect to physical and operational characteristics, how these variations may have affected the vessels performance and productivity is the subject ...

    • Economic performance indicators for coastal fisheries : the case of purse-seining in Khanh Hoa, Vietnam. 

      Luong, Nguyen Trong (Master thesis; Mastergradsoppgave, 2009-05-15)
      A field study on the economic performance indicators for coastal fisheries are needed in order to implement fisheries policy in Khanh Hoa as well as in Vietnam. The research project “Economic performance indicators for coastal fisheries - the case of pure-seining in Khanh Hoa” established to fulfill these demands. A questionnaire about technical characteristics and economic data is used for data ...

    • Economic performance of the gill netter fleets in the central area of Vietnam’s offshore fisheries 

      Dien, Mai Van (Master thesis; Mastergradsoppgave, 2009-05-15)
      The initial results of this study demonstrated that the offshore gillnets fleets in the Central of Vietnam can get high economic efficiency, an offshore gillnet vessel make a margin profit of 10%, the annual income of vessel can reach 51% of gross revenue. The average annual income of a fishing man is much higher than the average personal income on the national scale, corresponding to 156% in 2007. ...

    • Economic performance, technical efficiency and fishers’ perceptions of factors affecting fishing activities. A study of a Vietnamese purse seine fleet 

      Cao, Thi Hong Nga (Doctoral thesis; Doktorgradsavhandling, 2022-12-19)
      <p>The focus of this thesis is on the economic performance and technical efficiency of a Vietnamese fishing fleet by the use of data envelopment analysis (DEA). The double bootstrap method has been used to overcome some of the limitations of DEA. In addition, the dissertation evaluates fishers’ perceptions of negative events affecting the fishing activities. <p>The first of three papers presents ...