The effects of fisheries management on the Icelandic demersal fish value chain     

《Marine Policy》2016

Iceland׳s fishing industry has outperformed fishing industries in neighboring countries in recent years. This paper identifies key factors in market structure in recent decades that contribute to long run profitability of the Icelandic fishing (and fish processing) industry using semi-structured interviews with industry participants, and compares those with similar results from Norway. Further, the development of profitability in the Icelandic and Norwegian demersal fishing industries is used to assess the long run effects of different management systems on quality, product focus and profitability. The results indicate that three key changes in Icelandic regulation during the 1980s were important to the development of long run profitability within the fishing industry: the abolition of export barriers, the introduction of an individual transferable quota (ITQ) system and the establishment of fish auctions. A large and growing literature supports the role of ITQs in ensuring long run profitability. The importance of market structure for profitability has only recently been identified, affecting the ability of value chains to become market oriented and supply homogenous product flow from heterogeneous raw material. Comparison with Norway indicates that while individual transferable quota management does improve profitability in fishing to a certain extent, management systems must facilitate a strong market connection from consumers, through the stages of retail and processing, to fishers for the full realization of profit potential in the fishing industry.  相似文献   

http://www.sciencedirect.com/science/article/pii/S1674987114000425   总被引：1，自引：0，他引：1  

Ane K.Engvik  Peter M.Ihlen  Hkon Austrheim 《地学前缘(英文版)》2014,5(5):659-672

Na-metasomatism in the form of albitisation is regionally extensive in the Precambrian crust of southern Scandinavia and is particularly widespread in the Bamble Sector, the Kongsberg-Modum Sector and the Norwegian part of the Mylonite Zone. Sites of albitisation outside these belts are associated with hy- drothermal breccia pipes and fracture-bound alteration. The albitites are composed of near end-member sodic plagioclase （Ano 5Ab94-99） with minor carbonate （calcite and dolomite）, rutile, clinopyroxene （En30Fs21-23W047 49）, amphibole （edenite-pargasite）, quartz, titanite, tourmaline, epidote （Fe3＋ - 0.20 -0.85 a.p.f.u） and chlorite （Mg# = 0.81-0.89）. The albitites have been studied in detail in the region around the town of Kragem, and are described as albitisation along veins, as breccias, alhitic felsites, massive carbonate-bearing albitites and megascale clinopyroxene-titanite-bearing albitite. The strong fluid control on their formation is illustrated by the veining and mineral replacement reactions, showing fluid transport by a H20-CO2 fluid rich in Na, depleting Fe and Mg from the host rock, in accordance with calculated mass transfer. A study of the mineralogical replacement reactions in combination with a regional compilation has demonstrated the relationship between metasomatic processes and the for- mation of apatite, ruti｜e and Fe deposits. The albitites occur spatially associated with other metasomatic rocks such as scapolitised metagabbros. We document that metasomatism is an important mineral- and rock-forming process in the continental crust, which in the Bamble Sector is a part of the tectonome- tamorphic evolution of the Sveconorwegian orogen.  相似文献   

The effects of spatial targeting of fishing effort on the distribution of the Norway lobster,Nephrops norvegicus,on the Farn Deeps grounds,northeast England     

Michael C. Bell  Jon M. Elson  Julian T Addison 《新西兰海洋与淡水研究杂志》2013,47(5):1023-1037

Nephrops norvegicus is an essentially sedentary species of lobster that forms the basis of valuable fisheries in the northwest Atlantic and western Mediterranean. Fishers exploiting a sedentary stock are likely to visit the most profitable (highest catch rate) areas first. Such spatial targeting of fishing effort is likely to have important consequences for stock monitoring and assessment. We used underwater television surveys of Nephrops burrow densities on the Farn Deeps grounds, northeast England, to describe changes in abundance and distribution between the beginning and end of a winter fishing season. Above a threshold of c. 0.6 burrows m^–2, overwinter depletion increased with burrow density, consistent with fishing effort being targeted at the highest densities. A simple simulation model showed that this pattern of mortality is an expected consequence of spatially targeted fishing behaviour. The model also predicted that there is decreased spatial variability in density after fishing. An overall decrease in variability was not evident from the survey data, but geostatistical analysis indicated that there was “flattening” of the density profile along a north‐south axis, consistent with the dominant direction of commercial trawling. We concluded that Nephrops fishers are able to find and exploit the highest densities of their target species. A potential consequence is that catch per unit effort (CPUE) data used to monitor trends in this stock potentially could mask declines in stock abundance. CPUE might be more effective if analysed at finer spatial scales, but this is not currently possible. In the absence of these fine scale commercial data, fishery‐independent surveys (e.g., underwater television) are an important source of information on trends in stock abundance.  相似文献   

小气候、雪盖及土壤湿度对高山生态系统功能的影响(英文)     

Jrg LFFLER 《地理学报(英文版)》2007,17(1):3-19

1 Introduction High mountain landscapes above the tree-line are often regarded as close to nature, although human impact has obviously changed the environment, partly exceeding its carrying capac- ity (L?ffler, 2000). Due to their fragility regarding expe…  相似文献   

Landforms and uplift history of southern Norway     

Karna Lidmar-Bergstrm  C. D. Ollier  J. R. Sulebak 《Global and Planetary Change》2000,24(3-4)

  相似文献   

A 200-Year Tree-Ring Chronology of Pine from a Raised Bog in Sweden: Implication for Climate Change?   总被引：2，自引：0，他引：2  

Björn E. Gunnarson 《Geografiska Annaler: Series A, Physical Geography》1999,81(3):421-430

A dendrochronological study was made on fossil tree trunks of Scots pine, Pinus sylvestris , preserved in a peat bog at Hanvedsmossen, 50 km SW of Stockholm, Sweden. Of 56 sampled pines, 48 were assembled in a 204-year long floating chro-nology. The chronology spans 1686-1483 BC ± 23 years. The trunks are found at the very bottom of the peat accumulation. Because the roots stand in underlying clay, the tree stand germinated before or simultaneously with bog growth and provides maximum age for bog vegetation development which started c . 1480 BC. The pine growth steadily decreased during the last 30 years of the chronology and most trees died during the same period. It is proposed that the drainage outlets from Hanvedsmossen overgrew with brushwood simultaneously with the succession of pines, resulting in a higher sensitivity of tree growth to small changes in water levels. The preservation of the logs is suggested to be a result of a raised water table providing anaerobic conditions and later the logs were enveloped by peat growth. It is suggested that this period was the initial phase of the ensuing climate deterioration. The climate shifted to wetter conditions, i.e. higher amounts of precipitation, lower temperature or both. This resulted in lower evaporation giving additional peat bog growth and a locally raised water table.  相似文献   

Bridging theory and implementation – Testing an abstract classification system for practical mapping by field survey and 3D aerial photographic interpretation     

Heidrun A. Ullerud  Anders Bryn  Helle Skånes 《Norsk geografisk tidsskrift. Norwegian journal of geography》2019,73(5):301-317

ABSTRACT

The abstract classification system Nature in Norway (NiN) has detailed ecological definitions of a high number of ecosystem units, but its applicability in practical vegetation mapping is unknown because it was not designed with a specific mapping method in mind. To investigate this further, two methods for mapping – 3D aerial photographic interpretation of colour infrared photos and field survey – were used to map comparable neighbouring sites of 1 km² in Hvaler Municipality, south-eastern Norway. The classification accuracy of each method was evaluated using a consensus classification of 160 randomly distributed plots within the study sites. The results showed an overall classification accuracy of 62.5% for 3D aerial photographic interpretation and 82.5% for field survey. However, the accuracy varied for the ecosystem units mapped. The classification accuracy of ecosystem units in acidic, dry and open terrain was similar for both methods, whereas classification accuracy of calcareous units was highest using field survey. The mapping progress using 3D aerial photographic interpretation was more than two times faster than that of field survey. Based on the results, the authors recommend a method combining 3D aerial photographic interpretation and field survey to achieve effectively accurate mapping in practical applications of the NiN system.  相似文献   

Mapping mountain areas: learning from Global,European and Norwegian perspectives     

Martin F.PRICE  Tor ARNESEN  Erik GL?ERSEN  Marc J.METZGER 《山地科学学报》2019,(1):1-15

Defining the spatial extent of mountain areas has long been a challenge. In the present century, the availability of digital elevation models(DEMs) incorporated into geographic information systems(GIS) has allowed the definition of mountain areas based on topographic and other criteria. This paper presents the various delineations of mountains that have been prepared at three scales – global, regional(Europe), and national – and explores the reasons and processes leading to these delineations, and how they have been used. A detailed case study is then presented for Norway. Overall, two types of approaches to mapping mountains have been taken: first, considering mountains per se, based on elevation and/or topography; second, considering them among other categories, e.g., landforms or biogeographical, environmental or landscape zones. All attempts to map mountain areas derive essentially from the objectives of those commissioning and/or undertaking the work; a unitary definition remains unlikely.  相似文献   

Identifying soft sediments at sea using GIS-modelled predictor variables and Sediment Profile Image (SPI) measured response variables     

T. Bekkby  H.C. Nilsson  F. Olsgard  B. Rygg  P.E. Isachsen  M. Isus 《Estuarine, Coastal and Shelf Science》2008,79(4):631-636

Macrofauna composition and diversity in soft sediments are commonly used as “health indicators” in various pollution monitoring programmes worldwide. Hence, finding a modelling method for predicting the presence of soft sediments and enable production of digital maps of where soft sediments are likely to be found would be valuable for developing a cost-effective sampling design. This study presents a first-generation model that can predict where to find soft sediments in coastal areas with a complex topography and a mosaic of seabed habitat types. We used geophysical data that were quantitative, objectively defined (through GIS modelling) and integrated over time. We analysed, using a Generalised Additive Model (GAM) and the model-selection approach Akaike Information Criterion (AIC), the influence of in-situ measured depth and GIS-modelled terrain structures, wave exposure and current speed on the distribution of soft sediment measured using a Sediment Profile Image (SPI) camera. Our analyses showed that the probability of finding soft sediment was best determined by depth, terrain curvature and median current speed at the seafloor. These predictors were used to develop a spatial predictive GIS-model/-map (for parts of Skagerrak, Norway, with a spatial resolution of 25 m × 25 m) of the probability of soft seabed occurrence.  相似文献   

Heterogeneous deformation and mylonitization of a granulite complex,jotun-valdres nappe complex,Central South Norway     

Andreas G. Koestler 《Geological Journal》1988,23(1):1-13

The Helgedal Zone is the Caledonian, heterogeneously deformed base of the Jotun Complex, within the Jotun-Valdres Nappe Complex (Sognefjell, South Norway). It consists of an anastomosing system of shear zones isolating lozengeshaped lenses of less deformed rocks. Structural and geometrical features are described to define the type of deformation and to evaluate the tectonic significance of this zone. Granulitic gabbros and pegmatitic dykes are deformed together in the highly strained mylonitic zones. Microtextural investigations indicate that the quantitative relation between mafic and felsic minerals and the content of quartz determine the different behaviour of the two rock types during deformation.  相似文献