Polar Research Institute of Marine Fisheries And Oceanography

Murmansk, Russia

Polar Research Institute of Marine Fisheries And Oceanography

Murmansk, Russia

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Eriksen E.,Norwegian Institute of Marine Research | Prozorkevich D.,Polar Research Institute of Marine Fisheries And Oceanography | Trofimov A.,Polar Research Institute of Marine Fisheries And Oceanography | Howell D.,Norwegian Institute of Marine Research
PLoS ONE | Year: 2012

An 0-group fish survey is conducted annually in the Barents Sea in order to estimate fish population abundance. Data on jellyfish by-catch have been recorded since 1980, although this dataset has never been analysed. In recent years, however, the ecological importance of jellyfish medusae has become widely recognized. In this paper the biomass of jellyfish (medusae) in 0-60 m depths is calculated for the period 1980-2010. During this period the climate changed from cold to warm, and changes in zooplankton and fish distribution and abundance were observed. This paper discusses the less well known ecosystem component; jellyfish medusae within the Phylum Cnidaria, and their spatial and temporal variation. The long term average was ca. 9×10 8 kg, with some years showing biomasses in excess of 5×10 9 kg. The biomasses were low during 1980s, increased during 1990s, and were highest in early 2000s with a subsequent decline. The bulk of the jellyfish were observed in the central parts of the Barents Sea, which is a core area for most 0-group fishes. Jellyfish were associated with haddock in the western area, with haddock and herring in the central and coastal area, and with capelin in the northern area of the Barents Sea. The jellyfish were present in the temperature interval 1°C

Johannesen E.,Norwegian Institute of Marine Research | Hoines A.S.,Norwegian Institute of Marine Research | Dolgov A.V.,Polar Research Institute of Marine Fisheries And Oceanography | Fossheim M.,Norwegian Institute of Marine Research
PLoS ONE | Year: 2012

Direct and indirect effects of global warming are expected to be pronounced and fast in the Arctic, impacting terrestrial, freshwater and marine ecosystems. The Barents Sea is a high latitude shelf Sea and a boundary area between arctic and boreal faunas. These faunas are likely to respond differently to changes in climate. In addition, the Barents Sea is highly impacted by fisheries and other human activities. This strong human presence places great demands on scientific investigation and advisory capacity. In order to identify basic community structures against which future climate related or other human induced changes could be evaluated, we analyzed species composition and diversity of demersal fish in the Barents Sea. We found six main assemblages that were separated along depth and temperature gradients. There are indications that climate driven changes have already taken place, since boreal species were found in large parts of the Barents Sea shelf, including also the northern Arctic area. When modelling diversity as a function of depth and temperature, we found that two of the assemblages in the eastern Barents Sea showed lower diversity than expected from their depth and temperature. This is probably caused by low habitat complexity and the distance to the pool of boreal species in the western Barents Sea. In contrast coastal assemblages in south western Barents Sea and along Novaya Zemlya archipelago in the Eastern Barents Sea can be described as diversity "hotspots"; the South-western area had high density of species, abundance and biomass, and here some species have their northern distribution limit, whereas the Novaya Zemlya area has unique fauna of Arctic, coastal demersal fish. (see Information S1 for abstract in Russian). © 2012 Johannesen et al.

Lien V.S.,Norwegian Institute of Marine Research | Trofimov A.G.,Polar Research Institute of Marine Fisheries And Oceanography
Polar Research | Year: 2013

The Barents Sea throughflow accounts for approximately half of the Atlantic Water advection to the Arctic Ocean, while the other half flows through Fram Strait. Within the Barents Sea, the Atlantic Water undergoes considerable modifications before entering the Arctic Ocean through the St. Anna Trough. While the inflow area in the south-western Barents Sea is regularly monitored, oceanographic data from the outflow area to the north-east are very scarce. Here, we use conductivity, temperature and depth data from August/September 2008 to describe in detail the water masses present in the downstream area of the Barents Sea, their spatial distribution and transformations. Both Cold Deep Water, formed locally through winter convection and ice-freezing processes, and Atlantic Water, modified mainly through atmospheric cooling, contribute directly to the Barents Sea Branch Water. As a consequence, it consists of a dense core characterized by a temperature and salinity maximum associated with the Atlantic Water, in addition to the colder, less saline and less dense core commonly referred to as the Barents Sea Branch Water core. The denser core likely constitutes a substantial part of the total flow, and it is more saline and considerably denser than the Fram Strait branch as observed within the St. Anna Trough. Despite the recent warming of the Barents Sea, the Barents Sea Branch Water is denser than observed in the 1990s, and the bottom water observed in the St. Anna Trough matches the potential density at 2000 m depth in the Arctic Ocean. © 2013 V.S. Lien & A.G. Trofimov.

Fossheim M.,Norwegian Institute of Marine Research | Primicerio R.,University of Tromsø | Johannesen E.,Norwegian Institute of Marine Research | Ingvaldsen R.B.,Norwegian Institute of Marine Research | And 2 more authors.
Nature Climate Change | Year: 2015

Arctic marine ecosystems are warming twice as fast as the global average. As a consequence of warming, many incoming species experience increasing abundances and expanding distribution ranges in the Arctic. The Arctic is expected to have the largest species turnover with regard to invading and locally extinct species, with a modelled invasion intensity of five times the global average. Studies in this region might therefore give valuable insights into community-wide shifts of species driven by climate warming. We found that the recent warming in the Barents Sea has led to a change in spatial distribution of fish communities, with boreal communities expanding northwards at a pace reflecting the local climate velocities. Increased abundance and distribution areas of large, migratory fish predators explain the observed community-wide distributional shifts. These shifts change the ecological interactions experienced by Arctic fish species. The Arctic shelf fish community retracted northwards to deeper areas bordering the deep polar basin. Depth might limit further retraction of some of the fish species in the Arctic shelf community. We conclude that climate warming is inducing structural change over large spatial scales at high latitudes, leading to a borealization of fish communities in the Arctic. © 2015 Macmillan Publishers Limited.

Yaragina N.A.,Polar Research Institute of Marine Fisheries And Oceanography
ICES Journal of Marine Science | Year: 2010

Russian samples of cod caught in the Barents Sea during November-February, the period of migration to the overwintering and spawning grounds, were re-analysed by grouping the maturity stages recorded in three classes: immature, ripening, and apparently mature fish, with gonads of uncertain status. When treated by age class and gender, these three classes were characterized by significant differences in size (length and weight) and condition (somatic and a liver index). Within an age group, the group with uncertain status was on average consistently larger than the ripening fish and the latter group was on average larger than the immature component. However, in terms of condition, fish of uncertain status resembled the immature fish. Males and females displayed very similar patterns, although the levels were consistently lower for the former. The patterns are consistent with the interpretation that the gonads of uncertain status represent non-reproductive, mature fish. At the population level, the percentage of mature fish that presumably skip spawning varied annually between 4 and 21, but this has little effect on the perception of the overall development in spawning-stock biomass. No correlation was found between the non-reproductive fraction and environmental factors examined. © 2010 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved.

Bakay Y.I.,Polar Research Institute of Marine Fisheries And Oceanography
Journal of Ichthyology | Year: 2011

Special traits of ecology, zoogeography, formation of fauna of parasites, and occurrence of external lesions are investigated in redfish Sebastes mentella from the Norwegian Sea and the adjacent area of the Barents Sea. A considerable weakening of connection with bottom biocenoses in redfish in the pelagial of the Norwegian Sea indicates that it lives here for most of its annual life cycle. In redfish from south of the open part of the Norwegian Sea, there are noticeable differences in the fauna of parasites and in occurrence of external lesions from those in the fish from the north and east of this sea while traits characteristic of redfish from the Irminger Sea are present. © 2011 Pleiades Publishing, Ltd.

Howell D.,IMR | Filin A.A.,Polar Research Institute of Marine Fisheries And Oceanography
ICES Journal of Marine Science | Year: 2014

Recent observations have indicated that the cod distribution within the Barents Sea is expanding towards the northeast. The area into which the cod are expanding has historically been an area with large stocks of polar cod and capelin. It can be expected that the continued expansion of cod into this region would lead to greater availability of these forage fish for cod predation and have a direct impact on the forage fish stock. The distributional shift may also reduce the level of cod cannibalism. Such changes have implications for the management of both cod and capelin fisheries. In this paper, we use two different models (Gadget and STOCOBAR) to examine the effects of the changing overlap on cod and capelin. The results from the two models are compared to reduce uncertainty due to model formulation and exploit the different strengths of the two approaches. Although there are many uncertainties around the ongoing changes, the results indicate that the increased spatial overlap could contribute to modest rises by up to 20% in the average cod stock biomass, but with an increase in the impact of cannibalism, and hence an increased variability in the cod stock size. © 2013 International Council for the Exploration of the Sea. Published by Oxford University Press. All rights reserved.

Boitsov V.D.,Polar Research Institute of Marine Fisheries And Oceanography | Karsakov A.L.,Polar Research Institute of Marine Fisheries And Oceanography | Trofimov A.G.,Polar Research Institute of Marine Fisheries And Oceanography
ICES Journal of Marine Science | Year: 2012

Year-to-year variability in the temperature of Atlantic water (AW), which has a strong influence on the marine climate and ecosystem of the Barents Sea, was analysed using data from the Kola Section. With a positive trend in mean annual temperature during the late 20th century, only positive anomalies were registered during the past decade. In nine of those years, the temperature was warmer than the 19512000 long-term mean by 0.51.2°C, and in 2006, the historical maximum for the 110-year period of observations along the section was recorded. High air and water temperature coincided with reduced sea-ice cover, especially between October and April, when there is seasonal enlargement of the ice-covered area. An integral climate index (CI) of the Barents Sea based on the variability in temperature of AW, air temperature, and ice cover is presented. A prediction of future Barents Sea climate to 2020 is given by extrapolating the sixth degree polynomial approximating the CI. © 2012 International Council for the Exploration of the Sea.

Dolgov A.V.,Polar Research Institute of Marine Fisheries And Oceanography
Journal of Ichthyology | Year: 2013

Based on literature and new actual data from 2007-2012, a revised list of fish species inhabiting the Kara Sea is given. The modern ichthyofauna of the Kara Sea comprises 77 species of marine, anadromous, and freshwater fish from 24 families of 14 orders. For the first time, 12 fish species are indicated for this region. © 2013 Pleiades Publishing, Ltd.

Falk-Petersen J.,Akvaplan Niva | Falk-Petersen J.,University of Tromsø | Renaud P.,Akvaplan Niva | Anisimova N.,Polar Research Institute of Marine Fisheries And Oceanography
ICES Journal of Marine Science | Year: 2011

Since its introduction to the Barents Sea from the North Pacific in the 1960s, the red king crab (Paralithodes camtschaticus) has become invasive. The crab represents an important source of income, but also a potential threat to the highly productive fisheries in the region through its ecosystem impacts. A literature review was conducted, identifying factors contributing to the success of the crab as well as its interactions with native biota. Characteristics of the Barents Sea and the crab itself that may explain its success include suitable habitat for settlement and growth of the larvae; the wide range of habitats occupied throughout its life history, high mobility, generalist prey choice, low fishing pressure during establishment, and the lack of parasites. Being a large, bottom-feeding omnivore of great mobility, the king crab can significantly impact the ecosystem. Reduced benthic diversity and biomass have been registered in invaded areas. Important prey items include large epibenthic organisms whose structures also represent important habitat. Impacts on commercial and non-commercial fish species, through egg predation or indirect interactions, are difficult to detect and predict. © 2011 International Council for the Exploration of the Sea. Published by Oxford Journals. All rights reserved.

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