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Dvoretsky A.G.,RAS Murmansk Marine Biological Institute
Polar Biology | Year: 2012

Hyas araneus is the most common brachyuran crab in the coastal Barents Sea. Its epibionts were occasionally examined in 1940-1950s. To obtain modern information about associated organisms living on the crabs and compare new data with previous findings, the species composition, infestation indices, and spatial distribution of macro-epibionts colonizing H. araneus were examined in Dalnezelenetskaya Bay, a small semi-open gulf, in summer 2008-2010. A total of 41 taxa were observed on 48 crabs collected from depths ranging from 5 to 28 m. Red algae Ptilota plumosa (prevalence 39.6%) and Palmaria palmata (37.5%) as well as the copepod Harpacticus uniremis (39.6%) and the tube-dwelling worm Placostegus tridentatus (35.4%) predominated on the crabs. Infestation indices were similar in male and female crabs except for the turbellarian worm Peraclistus oophagus. Comparison with the previous study showed some changes in H. araneus fouling community that may be attributed to the shift of climatic regime or differences in sampling procedures. Presence of the amphipod Ischyrocerus commensalis, a new epibiont of H. araneus in the study area may be associated with introduction of the red king crab Paralithodes camtschaticus. Infestation indices of common epibionts depend on the crab shell conditions. Localization of epibionts strongly depended on the settlement patterns of larvae and hostassociate relationships. Typical fouling organisms were found predominantly on the carapaces or limbs, while the majority of mobile species were recorded on the gills. Colonization of great spider crabs is beneficial for the epibiont species, whereas some negative effects for the basibiont could not be excluded. © 2011 Springer-Verlag. Source


Dvoretsky V.G.,RAS Murmansk Marine Biological Institute
Polar Science | Year: 2012

Instantaneous mortality rates of the common planktonic copepod Oithona similis were investigated for the first time in Kola Bay, a region of the Barents Sea that is influenced by freshwater discharge. The rates were estimated in different seasons (December, May, September 2005 and July 2006). A vertical life table approach (VLT) was used to assess mortality. The total abundance of O. similis (copepodites IV and V, and adults) was highest in autumn and lowest in winter. The maximum mortality of O. similis for the stage pair copepodite IV-copepodite V (0.005 ± 0.001 day-1) occurred in December 2005, while the highest mortality rates for the pairs copepodite VM-adult male (0.453 ± 0.026 day-1) and copepodite VF-adult female (0.228 ± 0.006 day-1) occurred in summer 2006. Simple regression analyses showed that the total abundance of each stage and the mortality rates were positively significantly correlated with water temperature. The mortality rates for the stage pairs copepodite VM-adult male and copepodite VF-adult female were positively significantly correlated with chlorophyll a concentration. The abundance and mortality rate of O. similis in each season was determined by life cycle factors, and possibly by the dynamics of its food resources and potential predators. © 2012 Elsevier B.V. and NIPR. Source


Purchart L.,Mendel University in Brno | Nabozhenko M.V.,RAS Murmansk Marine Biological Institute
Acta Entomologica Musei Nationalis Pragae | Year: 2012

Larva and pupa of Deretus spinicollis Schawaller, 2004 are described and illustrated for the first time. The systematic position of the genus Deretus Gahan, 1900 is discussed and an updated key to larvae for known Palaearctic genera within the tribe Helopini is given. Source


Nekhaev I.O.,RAS Murmansk Marine Biological Institute
Biodiversity and Conservation | Year: 2016

In recent years, there have been frequent reports of invertebrate species newly recorded from particular areas of the Northeastern Atlantic, and it has often been suggested that these are the result of changes in species ranges due to recent warming. These suggestions make three assumptions: (1) that we have a good knowledge of the fauna of these areas; (2) that new records of “southern” species are more frequent than new records of “northern” species; (3) that climate change is the only factor affecting species range. I tested these assumptions on published records of 30 benthic molluscan species which have been found alive for the first time in the Russian part of the Barents Sea since 2006. Some of the discussed species are warm-water species and may have extended their ranges northward in response to climate change. However, our baseline knowledge of the molluscan fauna of this area before 2006 is limited by the frequent lack of molluscan specialists to study the available material, by the frequent lack of detailed publication and by changes in sampling and processing methods. New records of “southern” species are in fact not significantly commoner than new records of “northern” species. Also reasons other than climate change for observed changes in species distribution should be considered. © 2016 Springer Science+Business Media Dordrecht Source


Christiansen J.S.,University of Tromso | Christiansen J.S.,Abo Akademi University | Mecklenburg C.W.,California Academy of Sciences | Mecklenburg C.W.,Point Stephens Research | Karamushko O.V.,RAS Murmansk Marine Biological Institute
Global Change Biology | Year: 2014

In light of ocean warming and loss of Arctic sea ice, harvested marine fishes of boreal origin (and their fisheries) move poleward into yet unexploited parts of the Arctic seas. Industrial fisheries, already in place on many Arctic shelves, will radically affect the local fish species as they turn up as unprecedented bycatch. Arctic marine fishes are indispensable to ecosystem structuring and functioning, but they are still beyond credible assessment due to lack of basic biological data. The time for conservation actions is now, and precautionary management practices by the Arctic coastal states are needed to mitigate the impact of industrial fisheries in Arctic waters. We outline four possible conservation actions: scientific credibility, 'green technology', legitimate management and overarching coordination. © 2013 The Authors Global Change Biology Published by John Wiley & Sons Ltd. Source

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