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Bergstad O.A.,Norwegian Institute of Marine Research | Gjelsvik G.,Norwegian Directorate of Fisheries | Schander C.,University of Bergen | Hoines A.S.,Norwegian Institute of Marine Research
PLoS ONE | Year: 2010

The Macrourid fish roundnose grenadier, Coryphaenoides rupestris, is one of the most common benthopelagic fishes on the northern mid-Atlantic Ridge. The ecology of the species is comparatively well studied in continental slope waters of the North Atlantic, but not on the mid-Atlantic Ridge, which is a central mid-ocean area of its distribution. In total, 166 specimens from the RV G.O. Sars cruise in July 2004 were examined. The diet mainly comprised cephalopods, pelagic shrimps and fish. Pelagic and benthopelagic copepods were the most numerous prey, but did not contribute much on a weight basis. Cephalopods were by far the most important prey of the small grenadiers, while shrimps and fish became increasingly significant with increasing size. Previous studies from other areas have also found pelagic prey to be important, but in contrast to this study, cephalopods were generally of less importance. The study was an element of more wideranging food-web studies of the mid-Atlantic Ridge macro- and megafauna communities within the international MAR-ECO project. © 2010 Bergstad et al. Source


Glover K.A.,Norwegian Institute of Marine Research | Skaala O.,Norwegian Institute of Marine Research | Sovik A.G.E.,Norwegian Institute of Marine Research | Helle T.A.,Norwegian Directorate of Fisheries
Aquaculture Research | Year: 2011

Seven samples, each consisting of approximately 50 Atlantic salmon, were collected from five marine farms in Norway. These farms reported to rear fish originating from the same commercial breed; however, all samples followed a unique route of production from breeder to marine farm via egg, fry and smolt producers. A group of farmed escapees (n=50) were also captured. Following genotyping with 18 microsatellite loci, the global F ST was 0.083, and pair-wise values were as high as 0.158. Four clusters, with varying degrees of genetic differentiation, were identified among samples from the farms, and the source of the escapees was identified successfully. It is suggested that the genetic differences observed among samples from the farms were created through the process of genetic drift, facilitated by parallel sub-strains, extensive within-strain selection and low to moderate numbers of adults contributing to batches of eggs. In conclusion, this study has demonstrated that genetic identification of escaped Atlantic salmon, back to the farm of origin, may be possible even when farms rear fish reported to originate from a single breeder. © 2010 Blackwell Publishing Ltd. Source


Hunter R.,Norwegian Institute of Marine Research | Bergstad O.A.,Norwegian Institute of Marine Research | Hoines A.S.,Norwegian Institute of Marine Research | Gjelsvik G.,Norwegian Directorate of Fisheries
Journal of Ichthyology | Year: 2012

At least 16 macrourid fishes (Gadiformes, Macrouridae) inhabit the mid-Atlantic Ridge of the North Atlantic. To investigate the roles of macrourids in the food-web and compare feeding patterns of the most frequent co-occurring species, diet information on five of the species were described and compared. Pelagic and benthopelagic copepods were the most numerous prey but did not contribute much on a weight basis. Cephalopods were by far the most important prey of the small grenadiers, while shrimps and fish became increasingly significant with increasing size. Previous studies from other areas have also found pelagic prey to be important, but in contrast to this study, cephalopods were more important on the mid-Atlantic Ridge than in continental margin locations. © 2012 Pleiades Publishing, Ltd. Source

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