Blar i forfatter "Westgaard, Jon-Ivar"

Viser treff 1-8 av 8

    • Boreal marine fauna from the Barents sea disperse to Arctic Northeast Greenland 

      Andrews, Adam; Christiansen, Jørgen Schou; Bhat, Shripathi; Lynghammar, Arve; Westgaard, Jon-Ivar; Pampoulie, Christophe; Præbel, Kim (Journal article; Peer reviewed, 2019-04-09)
      As a result of ocean warming, the species composition of the Arctic seas has begun to shift in a boreal direction. one ecosystem prone to fauna shifts is the Northeast Greenland shelf. the dispersal route taken by boreal fauna to this area is, however, not known. This knowledge is essential to predict to what extent boreal biota will colonise Arctic habitats. Using population genetics, we show that ...

    • Extreme male-skewed sex ratios on spaning grounds for Atlantic cod Gadus morhua with typical coastal cod signatures of the Pan I (pantophysin) locus 

      Fevolden, Svein-Erik; Westgaard, Jon-Ivar; Pedersen, Torstein (Journal article; Tidsskriftartikkel; Peer reviewed, 2015)
      Large offshore and small inshore populations of Atlantic cod Gadus morhua L. display differences in migratory patterns and settling regimes, but little is known about possible differences in spawning behaviour. Cod presumably of the Norwegian coastal cod type were therefore sampled during 7 spawning seasons (2002-2013) in Malangen, northern Norway. A spawning site in neighbouring Balsfjord was sampled ...

    • Genetic differentiation between inshore and offshore populations of northern shrimp (Pandalus borealis) 

      Hansen, Agneta; Westgaard, Jon-Ivar; Søvik, Guldborg; Hanebrekke, Tanja Lexau; Nilssen, Einar Magnus; Jorde, Per Erik; Albretsen, Jon; Johansen, Torild (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-20)
      Many marine organisms have a permanent presence both inshore and offshore and spawn in multiple areas, yet their status as separate populations or stocks remain unclear. This is the situation for the northern shrimp (Pandalus borealis) around the Arctic Ocean, which in northern Norway represents an important income for a small-scale coastal fishery and a large-vessel offshore fleet. In Norwegian ...

    • Genetic investigation of swimbladder inflation anomalies in the European sea bass, Dicentrarchus labrax L. 

      Peruzzi, Stefano; Westgaard, Jon-Ivar; Chatain, B (Journal article; Tidsskriftartikkel; Peer reviewed, 2007)
      Although the aetiology of swimbladder inflation anomalies in important aquaculture species such as European sea bass D. labrax is not fully determined, culture conditions are commonly suggested as main contributory factors. Little information is available on whether swimbladder inflation has a genetic basis for its expression too. In this work, 24 full-sibling sea bass families from a 4 dams x 6 ...

    • Hierarchical genetic structure in an evolving species complex: Insights from genome wide ddRAD data in Sebastes mentella 

      Saha, Atal; Kent, Matthew Peter; Hauser, Lorenz; Drinan, Daniel P.; Nielsen, Einar E.; Westgaard, Jon-Ivar; Lien, Sigbjørn; Johansen, Torild (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-05-27)
      The diverse biology and ecology of marine organisms may lead to complex patterns of intraspecific diversity for both neutral and adaptive genetic variation. Sebastes mentella displays a particular life-history as livebearers, for which existence of multiple ecotypes has been suspected to complicate the genetic population structure of the species. Double digest restriction-site associated DNA was ...

    • Maximizing sampling efficiency to detect differences in fish community composition using environmental DNA metabarcoding in subarctic fjords 

      Guri, Gledis; Westgaard, Jon-Ivar; Yoccoz, Nigel; Wangensteen, Owen S.; Præbel, Kim; Ray, Jessica Louise; Kelly, Ryan P.; Shelton, Andrew Olaf; Hanebrekke, Tanja Lexau; Johansen, Torild (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-04-14)
      Environmental DNA (eDNA) has gained popularity as a tool for ecosystem biomonitoring and biodiversity assessment. Although much progress has been made regarding laboratory and fieldwork protocols, the issue of sampling efficiency requires further investigation, particularly in three-dimensional marine systems. This study focuses on fish community composition in marine ecosystems and aims to analyze ...

    • The One Ocean Expedition: Science and Sailing for the Ocean We Want 

      Huse, Geir; Baussant, Thierry; Becker, Meike; Biuw, Martin; Bødtker, Gunhild; Cook, Jeremy; Gomiero, Alessio; Grøsvik, Bjørn Einar; Handegard, Nils Olav; Hestnes, Arne Johan; Hole, Lars Robert; Husson, Berengere; Jaccard, Pierre Franqois; Johannessen, Johnny Andre; Krolicka, Adriana; Lien, Vidar Surén; Lindemann, Christian; Olsen, Are; Renner, Angelika; Lid, Sjur Ringheim; Steen-Larsen, Hans Christian; Strand, Espen; Westgaard, Jon-Ivar; Pedersen, Geir (Research report; Forskningsrapport, 2023-08-24)
      The One Ocean Expedition (OOE) was a 20-month long circumnavigation of the globe by the Norwegian sail training vessel Statsraad Lehmkuhl, and a recognised part of the UN decade of Ocean Science for Sustainable Development. The ship was equipped with modern instrumentation to collect high-quality data on ocean physics, chemistry, and biology. Many of the data series were available in near real time ...

    • Settling-depth vs. genotype and size vs. genotype correlations at the Pan I locus in 0-group Atlantic cod Gadus morhua 

      Fevolden, Svein-Erik; Westgaard, Jon-Ivar; Pedersen, Torstein; Præbel, Kim (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      We sampled 0-group juvenile Atlantic cod Gadus morhua L. within fjords and offshore in northern Norway from 1994 to 2008 using different gears for the 3 sampling depths: shore seine (0−3 m), pelagic trawl (various depths), and bottom trawl (>80 m). Frequencies of alleles at the Pan I locus (4218 fish analysed) showed highly significant differences among samples collected in the different habitats. ...