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To better understand fin whale vocalization behaviour in the Norwegian and Barents Seas, a large-aperture densely sampled coherent hydrophone array was deployed in late winter 2014 to monitor their vocalizations instantaneously over wide areas via passive ocean acoustic waveguide remote sensing (POAWRS). Here, we (i) provide a time-frequency characterization for different call types observed (20 Hz pulses, 130 Hz upsweeps, 30–100 Hz downsweep chirps, and 18–19 Hz backbeats); (ii) compare their relative abundances in three different coastal regions off Alesund, Lofoten, and Northern Finnmark; (iii) estimate the temporal and spatial distributions; (iv) source level distributions; and (v) probability of detection (PoD) regions for the more abundant 20 Hz pulse and 130 Hz upsweep call types. The fin whale vocalizations received over the diel cycle (24 h) were significantly more abundant by a factor of roughly seven off Northern Finnmark than the other two regions, associated with fish feeding activities. The source levels are estimated to be 190.5 ± 7.4 dB for the fin whale 20 Hz pulses and 170.3 ± 5.2 dB for the 130 Hz upsweeps. We find that fin whales are capable of producing each vocalization type either independently or simultaneously with other types, and the 20 Hz sound production in the fin whales involves a mechanism that generates a significantly less-intense second-order harmonic of the fundamental. [ABSTRACT FROM AUTHOR]

The biogeochemistry from a global climate model (Norwegian Earth System Model) has been compared with results from a regional model (NORWECOM.E2E), where the regional model is forced by downscaled physics from the global model. The study should both be regarded as a direct comparison between a regional and its driving global model to investigate at what extent a global climate model can be used for regional studies, and a study of the future climate change in the Nordic and Barents Seas. The study concludes that the global and regional model compare well on trends, but many details are lost when a coarse resolution global model is used to assess climate impact on regional scale. The main difference between the two models is the timing of the spring bloom, and a non-exhaustive nutrient consumption in the global model in summer. The global model has a cold (in summer) and saline bias compared with climatology. This is both due to poorly resolved physical processes and oversimplified ecosystem parameterization. Through the downscaling the regional model is to some extent able to alleviate the bias in the physical fields, and the timing of the spring bloom is close to observations. The summer nutrient minimum is one month early. There is no trend in future primary production in any of the models, and the trends in modelled pH and Ω Ar are also the same in both models. The largest discrepancy in the future projection is in the development of the CO2 uptake, where the regional suggests a slightly reduced uptake in the future. [ABSTRACT FROM AUTHOR]

Since January 2014, the reformed Common Fisheries Policy (CFP) of the European Union is legally binding for all Member States. It prescribes the end of overfishing and the rebuilding of all stocks above levels that can produce maximum sustainable yields (MSY). This study examines the current status, exploitation pattern, required time for rebuilding, future catch, and future profitability for 397 European stocks. Fishing pressure and biomass were estimated from 2000 to the last year with available data in 10 European ecoregions and 2 wide ranging regions. In the last year with available data, 69% of the 397 stocks were subject to ongoing overfishing and 51% of the stocks were outside of safe biological limits. Only 12% of the stocks fulfilled the prescriptions of the CFP. Fishing pressure has decreased since 2000 in some ecoregions but not in others. Barents Sea and Norwegian Sea have the highest percentage (>60%) of sustainably exploited stocks that are capable of producing MSY. In contrast, in the Mediterranean Sea, fewer than 20% of the stocks are exploited sustainably. Overfishing is still widespread in European waters and current management, which aims at maximum sustainable exploitation, is unable to rebuild the depleted stocks and results in poor profitability. This study examines four future exploitation scenarios that are compatible with the CFP. It finds that exploitation levels of 50–80% of the maximum will rebuild stocks and lead to higher catches than currently obtained, with substantially higher profits for the fishers. [ABSTRACT FROM AUTHOR]

Abstract: Dispersal of 137Cs from the nuclear submarine wrecks Komsomolets and K-159, which are resting on the seabed in the Norwegian and Barents Seas, respectively, is simulated using realistic rates and hypothetical scenarios. Furthermore, spatiotemporal 137Cs concentrations in Northeast Arctic cod and capelin are estimated based on survey data. The results indicate that neither continuous leakages nor pulse discharges will cause concentrations of 137Cs in cod muscle or whole body capelin exceeding the intervention level of 600 Bq/kg fw. Continuous leakages from Komsomolets and K-159 and pulse discharges from Komsomolets induced negligible activity concentrations in cod and capelin. A pulse discharge of 100% of the 137Cs-inventory of K-159 will, however, result in concentrations in muscle of cod of above 100 times the present levels in the eastern Barents Sea. Within three years after the release, 137Cs levels above 20 Bq/kg fw in cod are no longer occurring in the Barents Sea. [Copyright &y& Elsevier]

Abstract: A comparison of the mean conditions and variability in the climate and physical oceanographic characteristics between the Labrador Sea and surrounding shelves and the Norwegian and Barents seas is presented. The two regions are strongly advective systems being influenced by both cold, low saline flows from the Arctic and warm, high saline flows from the Atlantic. However, Arctic flows are more dominant in the Labrador Sea region, especially on the shelves, while Atlantic flows dominate in the Norwegian and a large part of the Barents Seas. In spite of this, the study reveals a general latitudinal dependence for several climate and oceanographic variables, including air temperatures, eastward winds, heat fluxes, and seasonal sea surface temperature range, within each of the two regions but with regional varying rates of change with latitude. We also confirm the previously reported out-of-phase relationships on interannual to decadal time scales of air and sea temperatures and sea-ice conditions between the Labrador Sea and the Norwegian and Barents seas regions from the 1950s until the mid-1990s. This is owing to their opposite response to the variability in the North Atlantic Oscillation (NAO). However, from the mid-1990s, air and sea temperatures in both regions generally have been in phase, showing strong warming and reduced ice coverage. The cause of this change is related to changes in the spatial structure of the atmospheric pressure patterns, resulting in a general reduction in the importance of NAO forcing over the North Atlantic. [Copyright &y& Elsevier]

Stated is an approach to the simulation of time series of storms and weather windows using the data on their frequency. Using the results of wind reanalysis for the Norwegian, Barents, and White seas for 1975-2002, the statistical relationships are obtained between the frequency of storms and the mean values of the number of storms and their continuous duration, as well as between the distribution functions of the number of storms and their continuous duration and the mean values. Based on the revealed regularities, the simulation model is constructed enabling to generate the time series of storms and weather channels. The model is verified by means of computing the residuals between the specified and simulated frequency of storm conditions for the set of 100 monthly series, as well as by means of comparing the results of the computation of weather channels based on the reanalysis and simulation data. [ABSTRACT FROM AUTHOR]

Abstract: Cloud microphysics is substantially affected by aerosol loading and the resulting changes in the reflective properties of the clouds can significantly affect the global radiation budget. A study of how marine low-level clouds over Barents Sea and the northern parts of the Norwegian Sea are affected by air mass origin has been performed by combining ground-based aerosol measurements with satellite cloud retrievals. Aerosol number size distributions have been obtained from measurement stations in northern Finland, and a trajectory model has been used to estimate the movement of the air masses. To identify anthropogenic influences on the clouds, the dataset has been divided according to aerosol loading. The clean air masses arrived to the investigation area from the north and the polluted air masses arrived from the south. Satellite derived microphysical and optical cloud parameters from the Moderate Resolution Imaging Spectrometer (MODIS) have then been analyzed for days when the trajectories coincided with marine low-level clouds over the investigated area. The cloud optical thickness (τ), cloud depth (H) and droplet number concentration (Nd) were significantly higher for the polluted days compared to the clean conditions, while the opposite was found for the cloud droplet effective radius (re). The H and Nd were derived from the satellite retrievals of τ and re. Furthermore, calculations of the aerosol cloud interaction relationship (ACI), relating Nd to boundary layer aerosol concentrations, resulted in a value of 0.17, which is in line with previous remote sensing studies. The results demonstrate that ground-based aerosol measurements can be combined with satellite cloud observations to study the indirect aerosol effect, and that the microphysics of marine sub-polar clouds can be considerably affected by continental aerosols. [Copyright &y& Elsevier]

Dispersal of 137Cs from Komsomolets and K-159 is simulated using realistic rates and hypothetical scenarios. Furthermore, spatiotemporal 137Cs concentrations in Northeast Arctic cod and capelin are estimated based on survey data. The results indicate that only pulse discharges from K-159 will cause concentrations of 137Cs in cod muscle exceeding the intervention level of 600Bq/kg fresh weight. A discharge of ≥10% of the 137Cs-inventory will result in concentrations in muscle of cod exceeding the intervention level for approximately two years. In fact, a discharge of 10% of the 137Cs-inventory results in an overlap of 8–30% between the different size groups of cod and levels that exceed the intervention level during the first year after the discharge. For capelin, individuals less than one year old during the first year after a discharge are more likely to be severely affected by discharges comprising ≥50% of the inventory. [Copyright &y& Elsevier]

Rey, F. 2012. Declining silicate concentrations in the Norwegian and Barents Seas. – ICES Journal of Marine Science, 69: 208–212.Since 1990, a decline in silicate concentrations together with increasing salinities has been observed in the Atlantic water of the Norwegian and Barents Seas. This decline in silicate has been found to be related to the relative proportion in which eastern and western source water masses from the northeastern North Atlantic enter the Norwegian Sea. [ABSTRACT FROM PUBLISHER]

Protecting Arctic ecosystems against potential adverse effects from anthropogenic activities is recognized as a top priority. In particular, understanding the accumulation and effects of persistent organic pollutants (POPs) in these otherwise pristine ecosystems remains a scientific challenge. Here, we combine more than 20 000 tissue concentrations, a food web bioaccumulation model, and time trend analyses to demonstrate that the concentrations of legacy-POPs in the Barents/Norwegian Sea fauna decreased 10-fold between 1985 and 2010, which reflects regulatory efforts to restrict these substances. In contrast, concentrations of fossil fuel derived PAHs in lower trophic levels (invertebrates and fish) increased 10 to 30 fold over the past 25 years and now dominate the summed POP burden (25 POPs, including 11 PAHs) in these biota. Before 2000, PCBs dominated the summed POP burden in top predators. Our findings indicate that the debate on the environmental impacts of fossil fuel burning should move beyond the expected seawater temperature increase and examine the possible environmental impact of fossil fuel derived PAHs. [ABSTRACT FROM AUTHOR]

The annual balance of radionuclides inflow/outflow was assessed for Cs and Sr isotopes in the Barents Sea, taking into account the atmospheric precipitation, inflow from the Norwegian and the White seas, as well as riverine discharge, liquid radioactive waste disposal (LRWD), and outflow to the adjacent seas. The original and published data for the period of 1950-2009 were analyzed. According to the multiyear dynamics (1960-2009), the inflow of Cs and Sr into the Barents Sea was significantly preconditioned by the Norwegian Sea currents; and precipitation played a major role in the 1950s, 1960s, and in 1986. Currently, the trans-border redeposition of Sr prevails over Cs redeposition in the Barents Sea, and constitutes about 99% of inflow of each element. [ABSTRACT FROM AUTHOR]

Abstract: 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. [ABSTRACT FROM AUTHOR]

Place-based management is any management action having implications for a specified area. Place-based management is seen as a key component to practical implementation of ecosystem approach to management, with marine spatial planning (MSP) being the currently most promoted approach. In the present paper we address the challenges of place-based management at local, regional and global (oceanic) spatial scales using case studies from the Northeast Atlantic with examples from Norway. Both ecological, governance and management complexity increases with increasing geographic scale, with associated increases in uncertainty and thus increasing need for managing under the precautionary approach. A process where (ecologically) valuable and vulnerable areas are defined early on is essential to successful place-based management under the ecosystem approach. Integrating across sectors and achieving necessary cooperation between involved institutions and stakeholders is also necessary. [ABSTRACT FROM AUTHOR]

More synchronous growth was observed between close, than more distantly separated populations of Atlantic salmon (Salmo salar), during both the first and the second year at sea. The marine growth of seven Norwegian populations, located between 60°N and 70°N, were correlated with sea surface temperatures (SSTs) in the Barents Sea, the Norwegian Sea, and the North Sea, and it was found that growth correlated best with the water temperatures in the area located closest to their home river. Growth was also compared with three broad-scale climate indices (North Atlantic Oscillation (NAO), Atlantic Multidecadal Oscillation, and subpolar gyre), with the strongest relationship occurring with the NAO index. However, SSTs explained more of the variability than the climatic indices did. Growth increment for the first year, but not the second year, was higher for southern than northern populations, mainly because of later smolt migration to sea in the north, and hence, a shorter growth season. For multi-sea-winter fish, all populations except one had a negative trend in growth with years for both the first and the second year at sea. For the second year at sea, this was most pronounced after the beginning of the 1980s. This is in accordance with the negative trend in pre-fishery abundance of adult salmon during the same period. On observe plus de croissance synchronisée entre les populations adjacentes que plus éloignées chez le saumon atlantique (Salmo salar), tant durant la première que la seconde année en mer. Nous avons mis en corrélation la croissance en mer de sept populations norvégiennes, établies entre 60°N et 70°N, et les températures de surface de la mer (SST) dans la mer de Barents, la mer de Norvège et la mer du Nord; la croissance est le mieux corrélée avec les températures des sites situés le plus près de leur rivière natale. Nous avons aussi comparé la croissance avec trois indices climatiques à grande échelle (l'oscillation nord-atlantique (NAO), l'oscillation atlantique multidécennale et le tourbillon subpolaire) et la relation la plus forte s'établit avec l'indice NAO. Cependant, les SST expliquent une plus grande partie de la variabilité que les indices climatiques. L'incrément de la croissance pour la première année, mais non pour la seconde, est plus élevé pour les populations du sud que pour celles du nord, surtout à cause de la migration plus tardive des saumoneaux vers la mer dans le nord et ainsi, de la période de croissance plus courte. Chez les poissons qui passent plusieurs hivers en mer, toutes les populations, sauf une, affichent une tendance négative de la croissance en fonction des années, tant pour la première que pour la deuxième année en mer. Pour la deuxième année en mer, la tendance est plus prononcée après le début des années 1980. Cela concorde avec la tendance négative dans l'abondance des saumons adultes pendant la même période. [ABSTRACT FROM AUTHOR]

Sea-bed diffractions are frequently observed for several of the fields in the Norwegian Sea and the Barents Sea. This is a challenge in time lapse seismic analysis, since diffracted multiples are difficult to remove by processing and therefore is a major source of poor time lapse data quality. In this work we test if the diffractions can be used for enhanced 4D interpretation. By analysing the time-shift of the sea-bed diffraction hyperbola between the base and monitor it is tested if changes in water velocity and tides can be estimated. Two models using time lapse diffraction analysis are tested: the first one simply adds time-shifts for the two branches of the diffraction hyperbola and this average time-shift is then used to estimate the water velocity change. The other method uses an inversion method based on the diffraction equation for a point diffractor to estimate the velocity change. In-line common-midpoint shifts are estimated by subtracting the time-shifts of both hyperbola branches followed by direct inversion. The diffraction based time-shifts are compared to time-shifts estimated by standard cross-correlation of the sea-bed reflection. The averaging method gives slightly higher uncertainties, while the inversion using an exact traveltime equation gives similar uncertainties compared to the sea-bed reflection method. [ABSTRACT FROM AUTHOR]

Interactions within and between species complicate quantification of climate effects, by causing indirect, often delayed, effects of climate fluctuations and compensation of mortality. Here we identify direct and indirect climate effects by analysing unique Russian time-series data from the Norwegian Sea–Barents Sea ecosystem on the first life stages of cod, capelin, herring and haddock, their predators, competitors and zooplanktonic prey. By analysing growth and survival from one life stage to the next (eggs–larvae–juveniles–recruits), we find evidence for both bottom-up, direct and top-down effects of climate. Ambient zooplankton biomass predicts survival of all species, whereas ambient temperature mainly affects survival through effects on growth. In warm years, all species experienced improved growth and feeding conditions. Cohorts born following a warm year will, however, experience increased predation and competition because of increased densities of subadult cod and herring, leading to delayed climate effects. While climate thus affects early growth and survival through several mechanisms, only some of the identified mechanisms were found to be significant predictors of population growth. In particular, our findings exemplify that climate impacts are barely propagated to later life stages when density dependence is strong. [ABSTRACT FROM AUTHOR]

Abstract: Abundance and biomass of the most important fish species inhabited the Barents and Norwegian Sea ecosystems have shown considerable fluctuations over the last decades. These fluctuations connected with fishing pressure resulted in the trophic structure alterations of the ecosystems. Resilience and other theoretical concepts (top-down, wasp-waste and bottom-up control, trophic cascades) were viewed to examine different response of the Norwegian and Barents Sea ecosystems on disturbing forces. Differences in the trophic structure and functioning of Barents and Norwegian Sea ecosystems as well as factors that might influence the resilience of the marine ecosystems, including climatic fluctuation, variations in prey and predator species abundance, alterations in their regular migrations, and fishing exploitation were also considered. The trophic chain lengths in the deep Norwegian Sea are shorter, and energy transfer occurs mainly through the pelagic fish/invertebrates communities. The shallow Barents Sea is characterized by longer trophic chains, providing more energy flow into their benthic assemblages. The trophic mechanisms observed in the Norwegian Sea food webs dominated by the top-down control, i.e. the past removal of Norwegian Spring spawning followed by zooplankton development and intrusion of blue whiting and mackerel into the area. The wasp-waist response is shown to be the most pronounced effect in the Barents Sea, related to the position of capelin in the ecosystem; large fluctuations in the capelin abundance have been strengthened by intensive fishery. Closer links between ecological and fisheries sciences are needed to elaborate and test various food webs and multispecies models available. [Copyright &y& Elsevier]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: Energy budget models for five marine ecosystems were compared to identify differences and similarities in trophic and community structure. We examined the Gulf of Maine and Georges Bank in the northwest Atlantic Ocean, the combined Norwegian/Barents Seas in the northeast Atlantic Ocean, and the eastern Bering Sea and the Gulf of Alaska in the northeast Pacific Ocean. Comparable energy budgets were constructed for each ecosystem by aggregating information for similar species groups into consistent functional groups. Several ecosystem indices (e.g., functional group production, consumption and biomass ratios, cumulative biomass, food web macrodescriptors, and network metrics) were compared for each ecosystem. The comparative approach clearly identified data gaps for each ecosystem, an important outcome of this work. Commonalities across the ecosystems included overall high primary production and energy flow at low trophic levels, high production and consumption by carnivorous zooplankton, and similar proportions of apex predator to lower trophic level biomass. Major differences included distinct biomass ratios of pelagic to demersal fish, ranging from highest in the combined Norwegian/Barents ecosystem to lowest in the Alaskan systems, and notable differences in primary production per unit area, highest in the Alaskan and Georges Bank/Gulf of Maine ecosystems, and lowest in the Norwegian ecosystems. While comparing a disparate group of organisms across a wide range of marine ecosystems is challenging, this work demonstrates that standardized metrics both elucidate properties common to marine ecosystems and identify key distinctions useful for fisheries management. [Copyright &y& Elsevier]

Study of redfish migration by traditional tagging methods is difficult because captured redfish usually prove to be nonviable. The main purpose of the present paper is to determine movement patterns of the beaked redfish (Sebastes mentella) juveniles based on data from Russian and Norwegian scientific trawl surveys conducted during autumn and winter of 1982-1995. The Petersen method was applied to analyse size composition of the beaked redfish catches. The conclusion made from prior researches that the beaked redfish year classes of 1982 and 1988 were strong compared to their neighbouring ones was confirmed. On the assumption that 'peaks' in the length distributions of survey catches display strong year classes, the annual corresponding lengths were defined for the 1982 and 1988 year classes of beaked redfish at different ages (from 0 to 7 years). Subsequently, using the database from trawl surveys and knowing the length of the beaked redfish from strong year classes at different ages, the distribution of these year classes by year was mapped. Based on these maps, migration patterns of the beaked redfish juveniles in the Barents and Norwegian Seas were inferred. The present study shows that the duration of the period from spawning to nursery area for one year class of the beaked redfish takes at least 2 years (age 0-1). Seasonal movements within the nursery area seem to last for 3-4 (5) years when the redfish is 2-4 (5) years old. The beaked redfish of the Norwegian-Barents sea population start leaving the nursery areas at age 5-6. [ABSTRACT FROM AUTHOR]

The results of the study of hydrocarbons (HCs): aliphatic (AHCs) and polycyclic aromatic hydrocarbons (PAHs) in bottom sediments (2019 and 2020, cruises 75 and 80 of the R/V Akademik Mstislav Keldysh) in the Norwegian-Barents Sea basin: Mohns Ridge, shelf Svalbard archipelago, Sturfiord, Medvezhinsky trench, central part of the Barents Sea, Novaya Zemlya shelf, Franz Victoria trough are presented. It has been established that the organo-geochemical background of the Holocene sediments was formed due to the flow of sedimentary material in the coastal regions of the Barents Sea on shipping routes. The anthropogenic input of HCs into bottom sediments leads to an increase in their content in the composition of Corg (in the sandy sediments of the Kaninsky Bank at an AHC concentration up to 64 μg/g, when its proportion in the composition of Corg reaches 11.7%). The endogenous influence on the of the Svalbard archipelago shelf in Sturfiord and in the Medvezhinsky Trench determines the specificity of local anomalies in the content and composition of HCs. This is reflected in the absence of a correlation between HCs and the grain size composition of sediments and Corg content, as well as a change in hydrocarbon molecular markers. At the same time, the sedimentary section is enriched in light alkanes and naphthalene's that may be due to emission during point discharge of gas fluid from sedimentary rocks of the lower stratigraphic horizons and/or sipping migration. [ABSTRACT FROM AUTHOR]

The article discusses the development of the objective climatology, as well as the characterization of the dynamical forcing of polar lows in the Nordic seas. It was found that 31% of polar low events exceeded the U/L ratio of 4.0. Also, polar lows of the north were observed to contrast with those of the south of the Nordic seas. Moreover, type C cyclones, which possess strong convection and weak low-level baroclinicity, were seen to dominate the population of polar lows in the southern Norwegian Sea. On the other hand, types A and B, which have stronger low-level baroclinicity and weaker convection, dominate the Barents and northern Norwegian seas.

The zooplankton biomass in the Barents Sea can vary by an order of magnitude from year to year. One reason for the large change is the varying transport of Calanus finmarchicus from the Norwegian Sea into the Barents Sea. How much of the population is stationary in the Barents Sea and how much is transported from the Norwegian Sea is unknown. Zooplankton samples were collected along the coast of North Norway from Lofoten and into the Barents Sea during the early juvenile fish survey in July 1989. The samples were evaluated with special emphasis on Calanus finmarchicus, which were sorted to copepodite stage. The probable drift route of the zooplankton and its origin were determined by examining the distribution of the different stages and the currents. The different stages were in very distinct bands, with the youngest stages in the south and the older stages in bands stretching east–west, with stage CV farthest north and east. When these patterns are compared with currents in 1989, the results support the theory that a large proportion of the C. finmarchicus stock is transported from the Norwegian Sea into the Barents Sea. [ABSTRACT FROM PUBLISHER]

Abundance estimates of copepodite and adult Calanus finmarchicus, Pseudocalanus spp., Oithona atlantica, O. similis, and Oncea borealis have been obtained twice a year by PINRO for the northeastern Norwegian Sea and the Barents Sea for the 30-year period 1964–1994. The data cover the upper 50 m of the water column during spring or early summer (i.e. April–July) along five inshore–offshore transects at 67°30′N, 71°10′N, 72°50′N, from North Cape to Bear Island, and at Kola (33°30′E). Along the Kola transect, data are also available for three depth strata covering the entire water column. For this study, information is extracted from these data sets for eight years, three cold (1979, 1980, and 1981) and several intermediate and warm years (1983, 1984, 1989, 1991, 1992). Spatial distribution patterns and the demography of C. finmarchicus, the target species, are described for the study area. In the time window studied, changes in abundance of C. finmarchicus between years appear to be a large-scale phenomenon throughout the entire study area. Unlike the results of previous studies, no clear interannual relationship between water temperature and copepod abundance was found. A correspondence analysis including the smaller copepod forms, as well as temperature and salinity data, revealed a consistent regional difference in the demography of Calanus, with stages from CIV to adult more common in the southwest of the study area. Other copepod taxa dominated over the shelf in the northeast of the study area, perhaps related to differences in the physical environment and in habitat preference. [ABSTRACT FROM PUBLISHER]

The physical oceanographic conditions in the Barents Sea depend mainly on the variability in the Atlantic inflow from the Norwegian Sea and the inflow of Arctic water from the Kara Sea and the Arctic Ocean. The transport out of the Barents Sea consists of transformed Atlantic water to the Arctic Ocean and also partly to the Norwegian Sea. [ABSTRACT FROM PUBLISHER]