Viser treff 380-399 av 1562

    • East is East and West is West: Population genomics and hierarchical analyses reveal genetic structure and adaptation footprints in the keystone species Paracentrotus lividus (Echinoidea) 

      Carreras, Carlos; García-Cisneros, Alex; Wangensteen Fuentes, Owen Simon; Ordóñez, Victor; Palacín, Creu; Pascual, Marta; Turon, Xavier (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-12-14)
      <i>Aim</i> - The Atlanto‐Mediterranean edible purple sea urchin, <i>Paracentrotus lividus</i>, is a commercially exploited keystone species in benthic communities. Its browsing activity can deeply modify the littoral landscape, and changes in its abundance are of major conservation concern. This species is facing nowadays contrasting anthropogenic pressures linked to predator release, exploitation ...
    • The ecological and economic value of cold-water coral ecosystems 

      Foley, Naomi; Armstrong, Claire W. (Journal article; Tidsskriftartikkel, 2010)
      Despite the growing scientific literature on cold-water corals (CWC) there appears to be no studies that address the economic values or economic management of the resource. This paper presents an overview of the goods and services of CWC and their associated biodiversity. Use and non-use values associated with CWC are presented, and the methods relevant for assessing their valuation are discussed. ...
    • Ecological linkages in a Caribbean estuary bay. 

      Andrade, Hector; Santos, Jorge; Ixquiac, MJ (Journal article; Tidsskriftartikkel, 2015-08-06)
      Central America and the western Caribbean form a center of freshwater and marine biodiversity that is now receiving attention in ecological and evolutionary studies. We conducted one integrated ecological study of Amatique Bay, Guatemala, a major estuary lagoon connected to the Mesoamerican Reef System, and provide novel information for management and conservation of similar systems across the ...
    • 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 ...
    • 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 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 ...
    • 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 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 value of coral reef and management effectiveness in Trao Reef locally managed marine reserve 

      Do, Hung Nguyen (Master thesis; Mastergradsoppgave, 2009-06-12)
      Trao Reef Locally Managed Marine Reserve was established in 2001 to protect coral reef being under threat because of human activities. However, the economic value of coral reef represents an important sight to help local people and resource managers in using and managing the resource effectively in the marine reserve has not been seen. By using financial analysis to calculate producer surplus of ...
    • Ecosystem based fishery management in Yangtze River Delta basin and fishery management opinions for Jiangxin island of Nanjing 

      Zhang, Xiao (Master thesis; Mastergradsoppgave, 2010-06-12)
      In the past ten years, China has developed to be one of the most important countries of fishery production field. Annually Chinese fishery products is increasing . In 2009 the total fishery production is 50.4 million tones.(China statistical reports,2009) As the same rate as the increase economy, the sharply development of fishery production is also remarkable. But there are serious problems ...
    • Ecosystem effects of red king crab invasion. A modelling approach using Ecopath with Ecosim 

      Falk-Petersen, Jannike (Master thesis; Mastergradsoppgave, 2004-05-28)
      Barents Sea ecosystem is limited. Due to the information available on benthos the Ecopath model of Sørfjord, Northern Norway, was used to investigate possible trophic changes with introduction of king crab to the model. A literature study of the king crab was conducted to find information on diet, mortality, consumption rate and other life history parameters required by the model. A short ...
    • Education : visitor management tool to reduce direct ecological impact resulting from marine tourism : case study: Con Dao, Vietnam 

      Pettersson, Lena (Master thesis; Mastergradsoppgave, 2009-05)
      Education is frequently used within visitor management, as a soft approach to fulfil different objectives e.g. increase awareness, alter behaviour. This thesis attempts to shed some light regarding how it can be used to reduce direct ecological impacts. For such to take place the tool needs to result in behavioural change(s) i.e. reduce destructive actions. In many situations though, education is ...
    • Effect of 11-ketotestosterone on sperm production by male spotted wolffish (Anarhichas minor) 

      Kugathaj, Subramaniam (Master thesis; Mastergradsoppgave, 2005-05-30)
      Three experiments were performed during spring 2004, to develop a method to elevate the blood plasma level of 11-ketotestosterone (11-KT) in male brood stock of spotted wolffish Anarhichas minor, and to study the effects of 11-KT on sperm production. Intraperitoneal implantation of silastic capsules containing 11-KT - coconut butter mixture and 11-KT - sesame oil mixture and intramuscular injection ...
    • Effect of a quality-improving codend on size selectivity and catch patterns of cod in bottom trawl fishery 

      Brinkhof, Jesse; Herrmann, Bent; Larsen, Roger B.; Veiga-Malta, Tiago (Journal article; Tidsskriftartikkel; Peer reviewed, 2019-02-26)
      A new codend concept developed and tested exhibited significantly improved quality of caught cod (<i>Gadus morhua</i>) compared to that of the conventional codend used in the Barents Sea bottom trawl fishery. However, the design of the new quality-improving codend raised concerns about its size selectivity and the possibility that higher retention probability could negatively impact the catch pattern ...
    • The effect of algae diets (Skeletonema costatum and Rhodomonas baltica) on the biochemical composition and sensory characteristics of Pacific cupped oysters (Crassostrea gigas) during land-based refinement 

      van Houcke, Jasper; Medina, Isabel; Mæhre, Hanne K; Cornet, Josiane; Cardinal, Mireille; Linssen, Jozef; Luten, Joop (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-06-20)
      <p>Oyster refinement, a common practice in France, is aimed at increasing the weight of oyster tissue and influencing the taste properties of the refined oysters. Refinement usually takes place in land-based systems where the oysters are fed with relatively high concentrations of microalgae. In this study the impact of feeding <i>Skeletonema costatum</i> and <i>Rhodomonas baltica</i> on the biochemical ...