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1.
The cod resources in the Barents Sea constitute the most important fisheries in Norway. In order to reduce resource allocation conflicts among different gear and vessel groups and to ensure profit for all participants throughout the value chain, the sector is thoroughly organized. The institutions established to ensure long-term sustainability, have been developed within the framework of a joint Norwegian–Russian fisheries management regime. However, due to a very high fishing mortality, the cod stock is now under severe pressure. In addition, a major part of the cod fisheries is highly seasonal and unable to be a stable supplier to neither the land-based industry nor demanding international markets. In parallel, cod farming is expected to become a new emerging industry, with potential to copy the success of farmed Atlantic salmon. Many actors within the cod fisheries fear the future competition from the growing cod farming sector. With reference to important attributes that characterize the cod fisheries and cod farming, this paper discusses how a future farming industry may affect the traditional cod fisheries. Moreover, we discuss how the fisheries may be forced to organize in the future to encounter the expected competition from cod farming. 相似文献
2.
Bjrn Skaare Olav Egeland 《Oceanic Engineering, IEEE Journal of》2006,31(3):599-613
A parallel force/position controller is proposed for the control of loads through the wave zone in marine operations. The controller structure has similarities to the parallel force/position control scheme used in robotics. The parallel force/position controller is tested for crane control in simulations and model experiments and the results are presented in this paper. To evaluate the performance of the proposed controller, we study three different control strategies for control of loads through the wave zone: active heave compensation, wave synchronization, and parallel force/position control. The parallel force/position controller gave improved results, in particular, a significant improvement of the minimum value of the wire tension, which is important to avoid snatch loads that may break the wire. The three strategies are tested and compared in simulations and experiments 相似文献
3.
Blubber samples, taken through the entire blubber column, were collected from three different anatomical locations on ringed seals (Phoca hispida). The outer and inner layers of these samples were analysed for concentrations of sigma PCBs (sum of the analysed congeners, polychlorinated biphenyls) and p,p'-DDE (4,4'-dichlorodiphenyldichloroethylene). No significant differences were found in blubber thickness or in per cent extractable lipid when comparing age- and sex-groups, or in extractable lipid content when comparing anatomical locations of the blubber or blubber depth. No significant differences were found between the three different anatomical locations with respect to the concentrations of sigma PCBs or p,p'-DDE. However, the concentrations of both sigma PCB and p,p'-DDE were significantly higher in the outer blubber layer compared to the inner. Higher levels of both sigma PCB and p,p'-DDE were found in males compared to females and juveniles in both the inner and outer parts of the blubber column. The most commonly used blubber sampling devices are biopsy tools that penetrate only the outer layer of the blubber. Analyses of such samples will not reflect the real body burden of organochlorines. Standard methods for sampling blubber of marine mammals should be developed so that comparative studies and longitudinal monitoring programs of pollutants in marine mammals can be conducted in a meaningful way. 相似文献
4.
K. Hylland M. Sandvik J. Utne Skre J. Beyer E. Egaas A. Goksyr 《Marine environmental research》1996,42(1-4)
Flounder (Platichthys flesus) is among the most common fish-species in Norwegian and European estuaries. It lives in or on sediments from which it also finds most of its food. The aim of the present work was to evaluate biomarkers in flounder for possible future use in monitoring programmes. There were clear biomarker responses in flounder following injection of model contaminants benzo[a]pyrene (B[a]P), PCB #156 and Cd, singly or in sequence. Cytochrome P4501A responded following injection of the organic contaminants and metallothionein (MT) following Cd injection. All groups receiving B[a]P, either singly or in combination with other contaminants, accumulated high levels of B[a]P-metabolites in bile. There was little change in glutathione-S-transferase activity (measured using CDNB as substrate) following the treatments. Starvation appeared to affect the response of hepatic MT to Cd, but none of the other biomarkers. PAH in sediments elicited strong biomarker responses in caged flounder, whereas sediment-associated metals appeared to be largely unavailable to flounder in this study. 相似文献
5.
Tanja Barth Sylvi Hiland Per Fotland Kjell Magne Askvik Bent Skaare Pedersen Anna Elisabet Borgund 《Organic Geochemistry》2004,35(11-12):1513
Twelve oil samples have been characterised by titration, FT-IR and chromatographic analysis to determine the differences between the organic acid composition of biodegraded and non-biodegraded oils. The biodegraded oils have higher total acid and total base contents, both by titration and extraction. The molecular weight ranges of the extracted acids are lowest in the biodegraded oils, and the equivalent weight calculations indicate a dominance of multi-functional molecules. Gel permeation chromatography gives a molecular weight range with most of the molecules between 300 and 500 g/mol. FT-IR shows that the extracted acids from biodegraded oils are more carboxylic and aliphatic while the non-degraded oils are more phenolic. Molecular analysis of the derivatised extracts give UCM envelopes for biodegraded oils, and no molecular identification. The results indicate that the acidic constituents in biodegraded oils are a product of the biodegradation, as the composition is very different from the non-biodegraded oils. 相似文献
6.
Sustainable fisheries are the main objective of Norwegian fisheries management. Despite powerful management tools, sustainability in the fisheries sector is not an easy task. There is no formal definition of the concept, and operationalization is vague. In recent years, private actors and non-governmental organizations (NGOs) have increased their impact on defining sustainability in the fisheries, which has reduced the power of the traditional fisheries management to determine its content. The lack of a clear strategy for fisheries management to increase sustainability makes it timely to address three research questions: (i) what is meant by “sustainable fisheries”, (ii) to what extent has the institutionalization of the Norwegian fisheries management channeled the sustainability concept towards specific trajectories, and (iii) what are the options and hard choices available to increase sustainability in the Norwegian fisheries in the future? These questions are investigated in this article. 相似文献
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8.
Ringed seal (Phoca hispida) is assumed to be the most important and common prey of polar bears (Ursus maritimus). However, during a scientific survey in the ice area of the northern Barents Sea east of Svalbard in June 1995, an unexpectedly high number of polar bears were observed feeding on harp seal (Phoca groenlandica) carcasses. Samples of both harp and ringed seals were obtained and organochlorine (OC) occurrence and pattern in these two potential polar bear prey species were determined. Significantly higher OC concentrations were found in harp seals, as compared to the ringed seals. All animals in the northern harp seal group were lean specimens in late moult. The industrial chemicals, polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB), and the OC pesticides bis-2,2,(chlorophenyl)-1,1,1-trichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), and chlordanes (CHLORs) were analysed in blubber. The concentrations of sigma PCB (sum of concentrations of 16 PCB congeners) and sigma DDT (sum of concentrations of p,p'-DDT and p,p'-DDE) in the northern harp seal group ranged from 2093 to 20,382 and 1460 to 10,381 ng g-1 lipid weight, with mean concentrations of 11,133 and 6847 ng g-1 lipid weight, respectively. The mean concentrations of the CHLORs, oxychlordane and trans-nonachlor, were 1311 and 3743 ng g-1 lipid weight, respectively, while the mean concentrations of HCB and HCH isomers (alpha-, beta- and gamma-HCH) were all < 500 ng g-1 lipid weight. No significant difference was found in the mean total blubber mass between the two seal species when collected in June. This indicates that polar bears preying on harp seals instead of ringed seals at this time of the year could accumulate significantly higher PCB concentrations. We suggest that polar bears feeding along the ice-edge east of Svalbard in May and June preferentially prey on harp seals instead of ringed seals, and that this may partly explain the variation in PCB concentrations among polar bears from the Norwegian Arctic. An hypothesis is that the harp seal may function as a transport vector of OCs into the high Arctic environment. 相似文献
9.
This article addresses the present status of seafood-oriented environmental methods and analyses, and pinpoints areas for further development. A recent study of the CO2 emissions associated with the production of farmed salmon in Norway, following the life cycle from hatching to consumption, is presented. The study was initiated due to the increased focus on environmental impacts from food production among consumer organizations, retailers, and authorities. In general, several methods are being currently applied to measure environmental performance. Unfortunately, different methods provide quite different results. An additional challenge is that most of these methods were originally developed for land-based production. If assumptions about the performance of the seafood industry are established on the basis of incorrect information, consequences for both the management and the market level may not be desirable. 相似文献
10.
Systems engineering principles in fisheries management 总被引：3，自引：0，他引：3
Fisheries management receives valuable, but often fragmented information from academic disciplines such as biology, economics, and social sciences. A multi-disciplinary perspective seems to be necessary if the fisheries are to become sustainable. Globally, overcapacity is considered as the most serious threat to sustainable fisheries, which indicates the need for a stronger integration of technological aspects into fisheries management. This paper discusses application of systems engineering principles and integration of technology into fisheries management. The systems engineering process facilitates implementation of multi-disciplinary information from researchers to fisheries managers in the decision-making towards sustainable fisheries, but may also be used to overcome multi-disciplinary obstacles among scientists. The article concludes that use of systems engineering principles may become a valuable contribution to fisheries management because of increased transparency and reduced risk associated with the decision-making process. 相似文献