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1.
The Svalbard Fisheries Protection Zone is an international institution on the brink of being challenged in a critical phase of being institutionalized as a Norwegian property regime. The potential disturbance comes from the zooplankton redfeed, a new and valuable resource harvestable within the zone. Though the pressures on Norway’s inspection routines in the zone are challenged at times, this article suggests that the zone as a management regime is a surprisingly robust institution still. Nevertheless, in such a critical phase it is important not to allow possible exogenous shocks to appear, and creating a separate redfeed regime for the plankton will allow the Norwegian government to bypass this possible disturbance and allow for continued solidification of the zone into an EEZ for Norway.  相似文献   

2.
The aim of the research was to investigate the diet of herring at different stages of its life cycle. For that purpose feeding of 0-group and immature herring in the Barents Sea, as well as of mature fish from the Norwegian Sea, was studied. 0-Group herring was sampled in the Barents Sea in August–September 2002–2005 during the international 0-group and trawl-acoustic survey of pelagic fish, as well as during the trawl-acoustic survey of demersal fish in November–December 2003–2004. Stomach samples of immature herring (1–3 years) were collected in late May and early of June 2001 and 2005 in the south-western part of the Barents Sea during the trawl-acoustic survey for young herring. Stomach samples of mature herring were collected in the Norwegian Sea in 1996, 1998, 1999, 2001, and 2002 in the course of the international trawl-acoustic survey of pelagic fish. Feeding intensity of herring of all age groups varied considerably between years and this was probably associated with availability and accessibility of their prey. The 0-group herring was found to have the most diverse diet, including 31 different taxa. In August–September, copepods, euphausiids, Cladocera, and larvae Bivalvia were most frequent in the diet of 0-group herring, but euphausiids and Calanus finmarchicus were the main prey taken. In November–December, euphausiids and tunicates were major prey groups. It was found that C. finmarchicus in the diet of 0-group herring was replaced by larval and adult euphausiids with increasing fish length. C. finmarchicus was the principal prey of immature herring and dominated in the diet of both small and large individuals and mainly older copepodites of C. finmarchicus were taken. Larval and adult euphausiids were found in stomachs of immature herring as well, but their share was not large. The importance of different prey for mature herring in the Norwegian Sea varied depending on the feeding area and length of the herring. On the whole C. finmarchicus and 0-group fish were the most important prey for mature herring diet, but fish prey were only important in a small sampling area. Hyperiids, euphausiids, tunicates, and pteropods were less important prey, and in 2002 herring actively consumed herring fry and redfish larvae.  相似文献   

3.
Very high concentrations of overwintering Calanus finmarchicus were found in the eastern Lofoten Basin of the Norwegian Sea close to the shelf break in January 2001–2002. A coupled 3D hydrodynamic and ecological model was used to study the formation of this deep overwintering aggregation and its stability. The ecological model includes nutrients, phytoplankton and microzooplankton in addition to a stage-structured model of C. finmarchicus. Using a Eulerian approach, the model was initiated with an overwintering stock evenly distributed in the oceanic regions of the Norwegian Sea, i.e. where depths>600 m. Spawning and development of the new generation take place in response to vertical mixing and phytoplankton development. Animals are assumed to begin their descent to overwintering depths of 700–1000 m as late stage Vs. Model results show that, in late summer, high concentrations of animals were found at overwintering depths near the shelf break north of the North Sea, off the northeastern Vøring Plateau and in the eastern Lofoten Basin along the slope of the Barents Sea shelf. They remained there for months due to deep eddies and southward, deep currents along the Norwegian shelf. The simulation experiments indicate that the combined effect of deep anticyclonic circulation and vertical migration behavior of the animals may explain the high concentrations of overwintering C. finmarchicus found in field surveys in the Eastern Lofoten Basin, close to the shelf break.  相似文献   

4.
The globalisation of the economy and the need for sustainable growth are having a strong influence on international sea freight transport and its infrastructures. Commercial sea ports, faced with the loss in ‘loyalty’ of their traffic and the appearance of ‘new rules in the game’, are developing new strategies in order to achieve the loyalty of their clients. The present paper is a reflection on the findings generated in recent years in the area of competitive port policies. The main focus is on the formulation of commercial and technological strategies, the new legislative framework and its consequences for the European Union in the context of the future ‘Common Ports Policy’.  相似文献   

5.
Egg production of Calanus finmarchicus was studied during joint basin-scale surveys in April–June 2003 in the Norwegian Sea. Surveys covered the whole Norwegian Sea and were conducted from Norwegian, Icelandic and Faroese research vessels. Stations were classified as being in pre-bloom, bloom or post-bloom phase according to levels of chlorophyll a and nitrate. Individual egg production rates and population egg production rates were calculated and compared between areas. Both individual egg production rates (eggs female−1 day−1) and population egg production rates (eggs m−2 day−1) were significantly higher in bloom areas compared with pre-bloom and post-bloom areas. However, when integrated over an estimated duration of the three phases, the time-integrated egg production (eggs m−2) in most years was highest in the pre-bloom phase, and this was explained by the longer duration of this phase compared with the two other phases.  相似文献   

6.
Treaties are usually concluded among national governments, which are also the traditional members of international organizations. The emergence of the European Community — a regional economic integration organization (REIO) to which member States have ceded some authority — has led to tensions in international environmental meetings and negotiations, in part because of foreign partners' uncertainty about how responsibilities are allocated between the REIO and its member States. This paper discusses the issues that arise when an REIO becomes a party to an international agreement or participates in an International organization, with particular attention to agreements and institutions that address international environmental issues.  相似文献   

7.
A White Paper on a new integrated management plan for the Norwegian Sea was launched by the Norwegian government in May 2009. Following international guidelines for ecosystem-based management, the plan provides an overall framework for managing all human activities (mainly oil and gas industry, fishing, and shipping) in the area to ensure the continued production and function of the ecosystem. The plan is based on an assessment of the present and projected future impact of human activities and of the interactions between them, taking into account deficits in current knowledge of ecosystem state and dynamics. Areas of particular value in terms of biodiversity or biological production were identified. In each of these valuable areas, any access for substantial human activity is to be carefully managed. To monitor the overall development of the Norwegian Sea, a set of indicators with associated environmental quality objectives have been selected. The approach used builds upon experience gained from the first integrated Norwegian management plan for a marine area, the Barents Sea–Lofoten region, developed in 2002–2006. Work towards a Norwegian management plan for the North Sea, including Skagerrak, was initiated in 2009.  相似文献   

8.
In order to point out the potential importance of the Kuroshio front as a feeding ground for the early post larvae of the Japanese sardine, distributions of copepod nauplii—the principal food for the larvae—were investigated.Nauplii were abundant in and near the front and in a warm water mass off Ensyu-nada, where the concentration of chlorophylla was high. Adult females ofParacalanus sp. were dominant in the copepod group there, and the protein synthesis activity shown by the RNA/DNA ratio was high. It is expected that copepod egg productivity is enhanced in the area where food phytoplankton is abundant, because the RNA/DNA ratio showed a positive correlation to chlorophylla in situ.In and near the front, high chlorophylla concentration—which is probably supported by nutrient supply caused by local upwelling and/or eddies at the front—contributes to the high RNA/DNA ratio of the copepods. The relatively large biomass of copepod nauplii at the front may be supported by female's high egg productivity. It is supposed, as a result, that food availability for the early post larvae of the Japanese sardine is increased in and near the Kuroshio front.  相似文献   

9.
The Lower Cretaceous succession in the Barents Sea is listed as a potential play model by the Norwegian Petroleum Directorate. Reservoirs may occur in deep to shallow marine clastic wedges located in proximity to palaeo-highs and along basin margins. In addition, shelf-prism-scale clinoforms with high amplitude anomalies in their top- and bottomsets have been reported from reflection seismic but they have never been drilled. In Svalbard, the exposed northwestern corner of the Barents Shelf, Lower Cretaceous strata of shelfal to paralic origin occur, and includes the Rurikfjellet (Valanginian–Hauterivian/lowermost Barremian), Helvetiafjellet (lower Barremian–lower Aptian) and Carolinefjellet formations (lower Aptian–middle Albian). By combining sedimentological outcrop studies and dinocyst analyses with offshore seismic and well ties, this study investigate the link between the onshore strata and the offshore clinoforms. Age-vise, only three (S1–S3) of the seismic sequences defined in the offshore areas correlate to the onshore strata; S1 correspond to the Rurikfjellet Formation, S2 to the Helvetiafjellet Formation and the lower Carolinefjellet Formation, and S3 to the upper Carolinefjellet Formation. Offshore, all three sequences contain generally southward prograding shelf-prism-scale clinoforms. A lower Barremian subaerial unconformity defines the base of the Helvetiafjellet Formation, and its extent indicates that most of the Svalbard platform was exposed and acted as a bypass zone in the early Barremian. Onshore palaeo-current directions is generally towards the SE, roughly consistent with the clinoform accretion-direction towards the S. The local occurrence of a 150 m thick succession of gravity flow deposits transitionally overlain by prodelta slope to delta front deposits in the Rurikfjellet Formation, may indicate that shelf-edges also developed in Svalbard. The late Hauterivian age of theses deposits potentially highlights the inferred offlapping nature of the Lower Cretaceous strata as they predate the lower Barremian unconformity, and thus record a hitherto unknown regression in Svalbard. The presence of the lower Barremian subaerial unconformity in Svalbard, the general southeastward palaeo-current directions, and the age-equivalent clinoform-packages south of Svalbard, suggests that the onshore and offshore strata is genetically linked and was part of the same palaeo-drainage system.  相似文献   

10.
The principal features of the marine ecosystems in the Barents and Norwegian Seas and some of their responses to climate variations are described. The physical oceanography is dominated by the influx of warm, high-salinity Atlantic Waters from the south and cold, low-salinity waters from the Arctic. Seasonal ice forms in the Barents Sea with maximum coverage typically in March–April. The total mean annual primary production rates are similar in the Barents and Norwegian Seas (80–90 g C m−2), although in the Barents, the production is higher in the Atlantic than in the ice covered Arctic Waters. The zooplankton is dominated by Calanus species, C. finmarchicus in the Atlantic Waters of the Norwegian and Barents Seas, and C. glacialis in the Arctic Waters of the Barents Sea. The fish species in the Norwegian Sea are mostly pelagics such as herring (Clupea harengus) and blue whiting (Micromesistius poutassou), while in the Barents Sea there are both pelagics (capelin (Mallotus villosus Müller), herring, and polar cod (Boreogadus saida Lepechin)) and demersals (cod (Gadus morhua L.) and haddock (Melanogrammus aeglefinus)). The latter two species spawn in the Norwegian Sea along the slope edge (haddock) or along the coast (cod) and drift into the Barents Sea. Marine mammals and seabirds, although comprising only a relatively small percentage of the biomass and production in the region, play an important role as consumers of zooplankton and small fish. While top-down control by predators certainly is significant within the two regions, there is also ample evidence of bottom-up control. Climate variability influences the distribution of several fish species, such as cod, herring and blue whiting, with northward shifts during extended warm periods and southward movements during cool periods. Climate-driven increases in primary and secondary production also lead to increased fish production through higher abundance and improved growth rates.  相似文献   

11.
The aim of the present work was to investigate the possible use of the clam Tapes philippinarum—a filter-feeding bivalve living on soft bottoms—in the monitoring of sediment pollution in the Lagoon of Venice (North-East Italy). To this end, two clam populations, exposed to different environmental conditions (a relative clean site and an industrial polluted area), have been monitored for the prevalence of the protozoan parasite Perkinsus sp. as well as for several biological parameters commonly used as determinants of contaminants exposure. First results showed a low prevalence, higher in the clean site, but a very diffuse distribution of the parasite throughout the two populations. Nevertheless, greater digestive cells height and longer lysosomal latency time were observed in clams from the clean area. As for the physiological stress-related parameters, even if clearance rates were always higher in these clams, scope for growth values indicated a more complicated biological response.  相似文献   

12.
A detailed study of the lipids of selected zooplankton species and scavenging amphipods in the near-bottom water layer (15–100 m above bottom, mab) was carried out at the BENGAL site in late summer 1998. Copepoda were the main contributors to the zooplankton, comprising 75% of the total abundance, followed by Ostracoda and Chaetognatha. Calanoid copepods of the family Metridinidae were predominant and accounted for more than 50% of all copepods.Two types of storage lipids were distinguished: triacylglycerols and wax esters. Ostracoda and the polychaete Vanadis sp. stored exclusively triacylglycerols whilst the bulk of the Copepoda accumulated wax esters, with the exception of the family Aetideidae. In the amphipods both lipid classes were found: Eurythenes gryllus stored wax esters and Paralicella spp. and Orchomene sp. triacylglycerols.The fatty acid composition was characterized by a high level of monounsaturated 18:1 (n—9), which is described as characteristic for animals living in the deeper layers of the water column, and to a lesser degree by 16:1 (n—7) and 20:5 (n—3), which are typical components of diatom lipids, and 22:6 (n—3), typical of dinoflagellates. The ratio of 18:1 (n—9):18:1 (n—7) fatty acids was between 5 and 10 in the copepods and indicates a carnivorous/omnivorous feeding behaviour in this group, whereas the higher ratios of 8–18 in the amphipods confirm their necrophagy. The fatty alcohols of the animals storing wax esters were dominated by the monounsaturated isomers 18:1 (n—9) and 18:1 (n—7).The predominance of wax esters as storage lipids in the deep-sea copepods indicates a strong seasonality in the availability of food. This is supported by the high levels of 16:1 (n—7), 20:5 (n—3) and 22:6 (n—3) fatty acids, which point to there being a direct link between the surface primary production and deep-sea copepods, probably via the rapid deposition of phytodetritus.  相似文献   

13.
SeaMARC II side-scan images, bathymetry, and single-channel seismic reflection data along the southern Peru—northern Chile forearc area between 16° and 23° S reveal a complex region of morpho-structural, submarine drainage and depression patterns. In the subducting plate area, the NW—SE trending primary normal fault system represented by trench-paralleled scarps was incipiently formed as the Nazca Plate was bent in the outer edge and further intensified as the plate approached the trench. The NE—SW trending secondary normal fault system that consists of discontinuous and smaller faults, usually intersect the primary trench-paralleled fault system. Similar to the Nazca Plate, the overriding continental plate also shows two major NW—SE and NE—SW trending fault systems represented by fault scarps or narrow elongated depressions.The submarine drainage systems represented by a series of canyon and channel courses appear to be partly controlled by the faults and exhibit a pattern similar to the onshore drainage which flows into the central region of the coastal area. Two large depressions occurring along the middle—upper slope areas of the continental margin are recognized as collapse and slump that perhaps are a major result of increased slope gradient. The subsidence of the forearc area in the southern Peru—northern Chile Continental Margin is indicated by: a) drainage systems flowing into the central region, b) the slope collapse and slumps heading to the central region, c) the deepening of the trench and inclining of the lower slope terrace to the central region, and d) submerging of the upper-slope ridge and the Peru—Chile Coast Range off the Arica Bight area.The subsidence of the forearc area in the southern Perunorthern Chile margin is probably attributed to a subduction erosion which causes wearing away and removal of the rock and sedimentary masses of the overriding plate as the Nazca Plate subducts under the South American Plate.  相似文献   

14.
Many studies have been conducted in northern Norwegian shelf regions to assess distributions and abundances of zooplankton in the last decade using towed Scanfish-conductivity, temperature and depth sensors (CTD)–optical plankton counter (OPC), and plankton nets. Significant progresses have been made in understanding dominant species, life histories and behavior, and in using size-structured data to identify dominant species in a certain size range. Using these Scanfish–CTD–OPC data, the analysis of zooplankton community size structures, compositions and their relationships with water types is made along the shelf region from Lofoten, North Cape to Varangerfjorden. From the relationships between the water types and zooplankton communities, the transports and exchanges of zooplankton communities between the Norwegian Coastal and Norwegian Atlantic Waters in regions near Malangsgrunnen and Nordvestbanken are examined. The biovolume (biomass) spectra are further analyzed for the productivity, trophic levels and seasonality of communities in these regions, indicating a steeper slope of the biovolume spectrum for a community dominated by herbivorous species in spring and a flatter slope for a community dominated by carnivorous–omnivorous species in winter. The comparison with the zooplankton biovolume spectra obtained in areas west of Antarctic Peninsula is made to examine and understand the differences in the zooplankton biovolume spectra, their trophic dynamics and potential human impacts between different regions.  相似文献   

15.
During specific intervals within Mesozoic and Cenozoic times, several areas of the southwestern Barents Sea were subjected to uplift and erosion. Areas with missing shallow stratigraphic interval sections and major erosion can be seen at several places along interpreted regional profiles in the southwestern Barents Sea. A new Normal Compaction Trend (NCT) for two selected shale– and sandstone–dominated lithologies has been constructed based on sonic logs in the southwestern Barents Sea. The shale– dominated NCT is calibrated to the Cretaceous shales in the northern North Sea and Norwegian Sea and applied to the Cretaceous shales of the Barents Sea. The sandstone–dominated NCT is calibrated to the Lower Jurassic Åre Formation of the Norwegian Sea and applied to the Lower Jurassic–Upper Triassic coastal plain section in the Barents Sea. By utilising the NCT model, the study estimates net apparent erosion in 28 selected Barents Sea wells based on comparison of sonic log velocities. A net apparent erosion map of the study area was constructed by gridding of the well values. The accuracy of the map is limited in areas with little well control, such as in the northwest, where the east–west transition into the southwestern Barents Sea region is poorly constrained. With that in mind, the map clearly shows two regional trends which dominate the erosion pattern in the study area; an increasing amount of erosion towards the north and a sharp decrease of erosion westwards of the hinge zone into the southwestern Barents Sea. The highest erosion estimates are observed towards Svalbard, with values up to 2500 m. The results of this study can be further utilized in petroleum system studies in the eroded areas.  相似文献   

16.
The Setschenow and McDevit—Long equations are applied to aromatic hydrocarbons in seawater by using solute surface area and recently available solubility data to evaluate the Setschenow constant. It is demonstrated that this approach avoids a previously encountered problem with the McDevit-Long equation while also pointing out fundamental theoretical discrepancies. Compounds that do not fit the presented semi-empirical relationship are of interest as they may exhibit abnormal partitioning behavior in seawater. Using this approach it is suggested that 1,2-benzanthracene and benzo(a)pyrene exhibit abnormal solution behavior in seawater.  相似文献   

17.
Northern Norwegian shelf regions are highly productive, supporting fisheries rich in commercially important species such as cod, herring and capelin. It has been long recognized that the mesoscale jets, meanders and eddies associated with interactions between the North Atlantic Current, Norwegian Coastal Current and regional bottom topographic features such as troughs, banks and shelfbreaks play important roles in transporting and retaining zooplankton. To investigate zooplankton distributions and their correspondence with the physical fields, three large-scale surveys with mesoscale resolutions on physical and biological fields were conducted in northern Norwegian shelf regions between latitudes 68°15′N and 70°15′N in springs of 2000–2002. Survey results provide insights into the relationships between zooplankton distributions and the physical features such as fronts, the Norwegian Coastal Current and eddies related to topographic features. The physical and biological data are integrated and analyzed focusing on water types, estimation of geostrophic currents from direct current measurements, along-shelf transport of zooplankton, and retention of zooplankton by the mesoscale meander–eddy over a typical bank area on the shelf. The estimated mean transport in the upper 100 m on the shelf in the survey region is approximately 6.4×103 tonnes wet weight day−1 northward. High zooplankton abundances were found over both Malangsgrunnen and Sveinsgrunnen banks. The specific accumulation rate from northward–southward transport in the upper 100 m over Malangsgrunnen was approximately 0.08 day−1, while variable currents with an offshore gradient of zooplankton abundance over Sveinsgrunnen implies an offshore dispersion of coastal-originated zooplankton cohort.  相似文献   

18.
Water samples were collected monthly for 3 years at 66°N, 2°E in the Norwegian Sea, 250 nautical miles off the Norwegian coast. Concentrations of mono- and polysaccharides were measured with the 2,4,6-tripyridyl-s-triazine (TPTZ) spectroscopic method. Total dissolved carbohydrates varied from 3.4 to 28.2 μM C of all samples and the ratio of carbohydrate to dissolved organic C (DOC) varied from an average of 14% at 0–25 m depth to 11% at 800–2000 m depth. This indicates that dissolved carbohydrates were a significant constituent of DOC in the Norwegian Sea. Polysaccharides varied from 0.4 to 21.5 μM C and monosaccharides from 0.7 to 11.7 μM C at all depths. The level of monosaccharides was relatively constant at 2.8–3.2 μM C below the euphotic zone, whereas polysaccharides showed more varying concentrations. Dissolved carbohydrates accumulated during the productive season, reaching maximum concentrations during summer although interannual differences were observed. A significant positive correlation between Chl a and soluble carbohydrate was found in one growing season with nutrient analyses. Average values for total carbohydrates were highest in the surface – 0 to 25 m – with 13.3 μM C and decreased to 8.4 μM C at 800–2000 m depth. The ratio of monosaccharides to polysaccharides exhibited a marked seasonal variation, increased from January to a maximum in June of 1.1, and declined to 0.5 in July.  相似文献   

19.
The Norwegian Sea is a migration and feeding ground for fin whales (Balaenoptera physalus) and humpback whales (Megaptera novaeangliae) in summer. During the last decade, significant structural changes in the prey community, including northerly expansion and movement in the distribution of pelagic fish species, have been reported from this ecosystem. However, little information on whale feeding ecology exists in the Norwegian Sea and surrounding waters. A total of 59 fin whales and 48 humpback whales were sighted during 864 h of observation over an observation distance of about 8200 nmi (15,200 km) in the Norwegian Sea from 15 July to 6 August 2006 and 2007. The fin whale group size, as mean (±SD), varied between one and five individuals (2.1 ± 1.2 ind.) and humpback whale group size varied between one and six individuals (2.5 ± 1.7 ind.). Fin‐ and humpback whales were observed mainly in the northern part of the study area, and were only found correlated with the presence of macro‐zooplankton in cold Arctic water. Humpback whales were not correlated with the occurrence of adult Norwegian spring‐spawning herring (Clupea harengus) except for the northernmost areas. Despite changes in the whale prey communities in the Norwegian Sea, no apparent changes in fin‐ or humpback whale distribution pattern could be found in our study compared to their observed summer distribution 10–15 years ago.  相似文献   

20.
The trophic structure of zooplankton was investigated in Fram Strait (north western Svalbard) in spring and autumn of 2003. Depth-stratified zooplankton samples were collected at 12 stations on the shelf (200 m), across the shelf-slope (500 m) and over deep water (>750 m), using a Multiple Plankton Sampler equipped with 0.180-mm mesh size nets.Higher zooplankton abundance and estimated biomass were found in the shelf area. Abundance and biomass were two times higher in August, when sea-surface temperature was higher than in May. Herbivores dominated numerically in May, and omnivores in August, suggesting a seasonal sequence of domination by different trophic groups. Cirripedia nauplii and Fritillaria borealis prevailed in spring, whereas copepod nauplii and Calanus finmarchicus were numerically the most important herbivores in autumn. Small copepods, Oithona similis and Triconia borealis, were the most numerous omnivorous species in both seasons, but their abundances increased in autumn. Chaetognatha (mainly Eukrohnia hamata) accounted for the highest abundance and biomass among predatory taxa at all deep-water stations and during both seasons. Regarding vertical distribution, herbivores dominated numerically in the surface layer (0–20 m), and omnivores were concentrated somewhat deeper (20–50 m) during both seasons. Maximum abundance of predators was found in the surface layer (0–20 m) in spring, and generally in the 20–50 m layer in autumn. This paper presents the first comprehensive summary of the zooplankton trophic structure in the Fram Strait area. Our goals are to improve understanding of energy transfer through this ecosystem, and of potential climate-induced changes in Arctic marine food webs.  相似文献   

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