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Jon Egil Skjæraasen

jones@imr
Forsker
Telefon: 99533850
Avdeling: Bunnfisk

Arbeidsområde

  • Population dynamics in Northeast Arctic gadoids
  • Skipped spawning and fecundity regulation
  • Mate choice and mating systems in broadcast spawners
  • Population structure and migration in Northeast Arctic gadoids

Curriculum Vitae

EDUCATION

10/2003 PhD (Dr scient) Marine Biology, University of Bergen, Norway
Thesis: ‘Implications of behaviour for maturation and spawning in cod’.
Advisors: Anne Gro Vea Salvanes & Trygve Nilsen
1996-1998 MSc (Cand scient) Marine Biology, The University of Technology and Science, Trondheim, Norway
Thesis: ‘Skater (Pisces: Rajidae) I Norskerenna og langs norsk kontinentalskråning: utbredelse, ernæring og biologi
Advisor: Odd Aksel Bergstad
1992-1997 BSc (Cand. mag) Biology/Chemistry. The University of Technology and Science, Trondheim, Norway (Examen philosophicum from the University of Oslo, 1989)

EMPLOYMENT
Research
05/2012 -> Researcher, Institute of Marine Research, Norway
Permanent position in the Research Group; Demersal fish
04/2009-04/2012 Researcher II, University of Bergen, Norway.
Working on the Norwegian Research Council project:
• ‘The occurrence of skipped spawning and its importance for population dynamics in Northeast Arctic gadoids’. 100%
01/2006-03/2009 Researcher II, University of Bergen, Norway.
Working on two projects funded by the Norwegian Research Council:
• ‘Interactions between wild and farmed cod: non-lethal impacts of escapees on wild populations’. 60%
• ‘Timing and determination of fecundity and skipped spawning: implications for stock recruitment theory of determinate spawners’. 40%
10/2003-12/2005 Post doctoral researcher. University of Bergen, Norway.
Employed on the project ‘Habitat choice and activity in relation to hypoxia and haemoglobin genotype in fish; comparisons across populations and species’ funded by the Norwegian Research council.
2000-2003 PhD student. University of Bergen, Norway
10/2002-01/2003 Guest PhD student, Dalhousie University, Canada
(with JA Hutchings)

Publikasjoner

Vitenskapelige artikler (NVI)

2024

Ecological interactions between farmed Atlantic salmon and wild Atlantic cod populations in Norway: A review of risk sources and knowledge gaps

Thomas Bøhn, John Frederik Strøm, Pablo Sanchez-Jerez, Nigel B. Keeley, Torild Johansen, Karl Øystein Gjelland, Nina Sandlund, Bjørn Steinar Sæther, Ingeborg Mathisen Sætra, Esben Moland Olsen, Jon Egil Skjæraasen, Sonnich Meier, Terje van der Meeren, Pål Arne Bjørn
Reviews in Aquaculture
2024

Continuous sound from a marine vibrator causes behavioural responses of free-ranging, spawning Atlantic cod (Gadus morhua)

Kate McQueen, Lise Doksæter Sivle, Tonje Nesse Forland, Justin James Meager, Jon Egil Skjæraasen, Esben Moland Olsen, Ørjan Karlsen, Petter Helgevold Kvadsheim, Karen de Jong
Environmental Pollution (1987) 344
2023

Large females connect Atlantic cod spawning sites

Olsen Esben Moland, Ørjan Karlsen, Jon Egil Skjæraasen
Science 382 p. 1181-1184
2023

Large females connect Atlantic cod spawning sites

Esben Moland Olsen, Ørjan Karlsen, Jon Egil Skjæraasen
Science 382 p. 1181-1185
2023

Movement diversity and partial sympatry of coastal and Northeast Arctic cod ecotypes at high latitudes

Thomas Bøhn, Jon Egil Skjæraasen, Karl Øystein Gjelland, Ørjan Karlsen, Torild Johansen, Tanja Lexau Hanebrekke, Pål Arne Bjørn, Esben Moland Olsen
Journal of Animal Ecology
2023

Terrestrial fatty acids from feed oil in feed for farmed salmonids are transferred to the liver, gonads, and muscle of wild Atlantic cod (Gadus morhua)

Sonnich Meier, Terje van der Meeren, Jon Egil Skjæraasen, Raymond Bannister, Josef Rasinger, Ørjan Karlsen
ICES Journal of Marine Science 80 p. 1143-1154
2023

Terrestrial fatty acids from feed oil in feed for farmed salmonids are transferred to the liver, gonads, and muscle of wild Atlantic cod (Gadus morhua)

Sonnich Meier, Terje van der Meeren, Jon Egil Skjæraasen, Raymond J Bannister, J.D. Rasinger, Ørjan Karlsen
ICES Journal of Marine Science 80 p. 1143-1154
2023

Behavioural responses of wild, spawning Atlantic cod (Gadus morhua L.) to seismic airgun exposure

Kate McQueen, Jon Egil Skjæraasen, D Nyqvist, Esben Moland Olsen, Ørjan Karlsen, Justin James Meager, Petter Helgevold Kvadsheim, Nils Olav Handegard, Tonje Nesse Forland, Karen de Jong, Lise Doksæter Sivle
ICES Journal of Marine Science 80 p. 1052-1065
2023

Movement diversity and partial sympatry of coastal and Northeast Arctic cod ecotypes at high latitudes

John Fredrik Strøm, Thomas Bøhn, Jon Egil Skjæraasen, Karl Øystein Gjelland, Ørjan Karlsen, Torild Johansen, Tanja Lexau Hanebrekke, Pål Arne Bjørn, Esben Moland Olsen
Journal of Animal Ecology
2023

Terrestrial fatty acids from feed oil in feed for farmed salmonids are transferred to the liver, gonads, and muscle of wild Atlantic cod (Gadus morhua).

Sonnich Meier, Terje van der Meeren, Jon Egil Skjæraasen, Raymond J Bannister, J.D. Rasinger, Ørjan Karlsen
ICES Journal of Marine Science
2022

Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak (WGNSSK)

Anja Helene Alvestad, Jurgen Batsleer, Alan Baudron, Casper W. Berg, Chun Chen, Harriet S. Cole, José De Oliveira, Come Denechaud, Elise Eidset, Raphael Girardin, Ghassen Halouani, Holger Haslob, Alexander Holdgate, Nis Sand Jacobsen, Alexander Kempf, Alexandros Kokkalis, Tiago Veiga-Malta, Carlos Mesquita, Tanja Miethe, Iago Mosqueira, Nikolai Nawri, Coby Needle, Anders Nielsen, J. Rasmus Nielsen, Alessandro Orio, Yves Reecht, Jon Egil Skjæraasen, Guldborg Søvik, Andreas Sundelöf, Klaas Sys, Marc Taylor, Mikael van Deurs, Lies Vansteenbrugge, Francesca Vitale, Kathrin Vossen, Nicola Walker, Fabian Zimmermann
ICES Scientific Reports 4
2022

Habitat associations of juvenile Atlantic cod (Gadus morhua L.) and sympatric demersal fish communities within shallow inshore nursery grounds

Katherine Mary Dunlop, Arved Staby, Terje van der Meeren, Nigel B. Keeley, Esben Moland Olsen, Raymond Bannister, Jon Egil Skjæraasen
Estuarine, Coastal and Shelf Science 279
2022

Attraction of cod Gadus morhua from coastal spawning grounds to salmon farms

Jon Egil Skjæraasen, Ørjan Karlsen, Øystein Ole Gahr Langangen, Sonnich Meier, Katherine Mary Dunlop, Terje van der Meeren, Nigel B. Keeley, Mari Skuggedal Myksvoll, Geir Dahle, Even Moland, Rune Nilsen, Kristine Marit Schrøder Elvik, Raymond Bannister, Esben Moland Olsen
Aquaculture Environment Interactions 14 p. 229-242
2022

Spawning Atlantic cod (Gadus morhua L.) exposed to noise from seismic airguns do not abandon their spawning site

Kate McQueen, Justin James Meager, Daniel Nyqvist, Jon Egil Skjæraasen, Esben Moland Olsen, Ørjan Karlsen, Petter Helgevold Kvadsheim, Nils Olav Handegard, Lise Doksæter Sivle, Tonje Nesse Forland
ICES Journal of Marine Science 79 p. 2697-2708
2022

ICES 2022 - Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak (WGNSSK)

Anja Helene Alvestad, Jurgen Batsleer, Alan Baudron, Casper W. Berg, Chun Chen, Harriet S. Cole, José De Oliveira, Come Denechaud, Elise Eidset, Raphael Girardin, Ghassen Halouani, Holger Haslob, Alexander Holdgate, Nis Sand Jacobsen, Alexander Kempf, Alexandros Kokkalis, Tiago Veiga-Malta, Carlos Mesquita, Tanja Miethe, Iago Mosqueira, Nikolai Nawri, Coby Needle, Anders Nielsen, J. Rasmus Nielsen, Alessandro Orio, Yves Reecht, Jon Egil Skjæraasen, Guldborg Søvik, Andreas Sundelöf, Klaas Sys, Marc Taylor, Mikael van Deurs, Lies Vansteenbrugge, Francesca Vitale, Kathrin Vossen, Nicola Walker, Fabian Zimmermann
ICES Scientific Reports 4
2021

Highly mixed impacts of near-future climate change on stock productivity proxies in the North East Atlantic

Olav Sigurd Kjesbu, Svein Sundby, Anne Britt Sandø, Maud Alix, Solfrid Sætre Hjøllo, Maik Tiedemann, Mette Skern-Mauritzen, Claudia Junge, Maria Fossheim, Cecilie Broms, Guldborg Søvik, Fabian Zimmermann, Kjell Harald Nedreaas, Elena Eriksen, Hannes Höffle, Ann Merete Hjelset, Cecilie Kvamme, Yves Reecht, Halvor Knutsen, Asgeir Aglen, Ole Thomas Albert, Erik Berg, Bjarte Bogstad, Caroline Durif, Kim Aleksander Tallaksen Halvorsen, Åge Sigurd Høines, Carsten Hvingel, Edda Johannesen, Espen Johnsen, Even Moland, Mari Skuggedal Myksvoll, Leif Nøttestad, Erik Joel Steinar Olsen, Georg Skaret, Jon Egil Skjæraasen, Aril Slotte, Arved Staby, Erling Kåre Stenevik, Jan Erik Stiansen, Martina H. Stiasny, Jan Henry Sundet, Frode Bendiksen Vikebø, Geir Huse
Fish and Fisheries 23 p. 601-615
2021

Triploid Atlantic salmon and triploid Atlantic salmon × brown trout hybrids have better freshwater and early seawater growth than diploid counterparts

Thomas Fraser, Hilde Lerøy, Tom Johnny Hansen, Jon Egil Skjæraasen, Valentina Tronci, Cindy Pinto Pedrosa, Per Gunnar Fjelldal, Tom Ole Nilsen
Aquaculture 540
2021

Impact of salmon farming on Atlantic cod spatio-temporal reproductive dynamics

Jon Egil Skjæraasen, Ørjan Karlsen, Øystein Ole Gahr Langangen, Terje van der Meeren, Nigel B. Keeley, Mari Skuggedal Myksvoll, Geir Dahle, Even Moland, Rune Nilsen, Kristine Marit Schrøder Elvik, Raymond Bannister, Esben Moland Olsen
Aquaculture Environment Interactions 13 p. 399-412
2021

Genetic structuring in Atlantic haddock contrasts with current management regimes

Paul R. Berg, Per E. Jorde, Kevin A. Glover, Geir Dahle, John B. Taggart, Knut Korsbrekke, Gjert E. Dingsør, Jon E. Skjæraasen, Peter J. Wright, Steven X. Cadrin, Halvor Knutsen, Jon-Ivar Westgaard
ICES Journal of Marine Science 78 p. 1-13
2020

Large annual variation in the amount of skipped spawning for female Northeast Arctic haddock Melanogrammus aeglefinus

Jon Egil Skjæraasen, Knut Korsbrekke, Gjert Endre Dingsør, Øystein Langangen, Anders Frugård Opdal, Christian Jørgensen
Fisheries Research 230
2018

Spatial and temporal dynamics of European hake (Merluccius merluccius) in the North Sea

Arved Staby, Jon Egil Skjæraasen, Daniel Howell, Audrey J. Geffen
ICES Journal of Marine Science 76 p. 2033-2044
2018

Vertebral column deformity in adult wild haddock(Melanogrammus aeglefinus)

Laith A. Jawad, Tom Johnny Hansen, Sonnich Meier, Jon Egil Skjæraasen, Per Gunnar Fjelldal
Journal of Fish Diseases 41 p. 1909-1915
2018

Multi-decadal variations in spawning ground use in Northeast Arctic haddock (Melanogrammus aeglefinus)

Øystein Langangen, Leif Christian Stige, Kristina Øie Kvile, Natalia A. Yaragina, Jon Egil Skjæraasen, Frode Bendiksen Vikebø, Geir Ottersen
Fisheries Oceanography 27 p. 435-444
2017

The behavioural diversity of Atlantic cod: insights into variability within and between individuals

Justin James Meager, Anders Fernø, Jon Egil Skjæraasen
Reviews in Fish Biology and Fisheries 28 p. 153-176
2017

Timecourse of oocyte development in saithe Pollachius virens

Jon Egil Skjæraasen, Jennifer Ann Devine, Jane Aanestad Godiksen, Merete Fonn, Håkon Magne Otterå, Olav Sigurd Kjesbu, Birgitta Norberg, Øystein Langangen, Ørjan Karlsen
Journal of Fish Biology 90 p. 109-128
2015

Skipped spawning in Northeast Arctic haddock Melanogrammus aeglefinus

Jon Egil Skjæraasen, Knut Korsbrekke, Trygve Nilsen, Merete Fonn, Olav Sigurd Kjesbu, Gjert Endre Dingsør, Richard David Marriott Nash
Marine Ecology Progress Series 526 p. 143-155
2015

Increased reactivity and monoamine dysregulation following stress in triploid Atlantic salmon (Salmo salar)

Thomas Fraser, Marco Antonio Vindas, Per Gunnar Fjelldal, Svante Winberg, Per-Ove Thörnqvist, Øyvind Øverli, Jon Egil Skjæraasen, Tom Johnny Hansen, Ian Mayer
Comparative Biochemistry and Physiology A 185 p. 125-131
2015

Vaccination and triploidy increase relative heart weight in farmed Atlantic salmon, Salmo salar L

Tom Fraser, Ian Mayer, Tom Johnny Hansen, Trygve Poppe, Jon Egil Skjæraasen, Erling Olaf Koppang, Per Gunnar Fjelldal
Journal of Fish Diseases 38 p. 151-160
2014

The effect of triploidy on the efficacy and physiological response to anesthesia with MS 222 and isoeugenol in Atlantic salmon post-smolts

Tom Fraser, Ian Mayer, Jon Egil Skjæraasen, Tom Johnny Hansen, Per Gunnar Fjelldal
Aquaculture International 22 p. 1347-1359
2014

Trade-offs between growth and reproduction in wild Atlantic cod

Arild Folkvord, Christian Jørgensen, Knut Korsbrekke, Richard David Marriott Nash, Trygve Nilsen, Jon Egil Skjæraasen
Canadian Journal of Fisheries and Aquatic Sciences 71 p. 1106-1112
2014

The effect of triploidy on vaccine side-effects in Atlantic salmon

Tom Fraser, Tom Johnny Hansen, Ian Mayer, Jon Egil Skjæraasen, Kevin Glover, Florian Sambraus, Per Gunnar Fjelldal
Aquaculture 433 p. 481-490
2014

Synergies between climate and management for Atlantic cod fisheries at high latitudes

Olav Sigurd Kjesbu, Bjarte Bogstad, Jennifer Ann Devine, Harald Gjøsæter, Daniel Howell, Randi Ingvaldsen, Richard David Marriott Nash, Jon Egil Skjæraasen
Proceedings of the National Academy of Sciences of the United States of America 111 p. 3478-3483
2014

Making use of Johan Hjort's "unknown" legacy: Reconstruction of a 150-year coastal time-series on northeast Arctic cod (Gadus morhua) liver data reveals long-term trends in energy allocation patterns

Olav Sigurd Kjesbu, Anders Frugård Opdal, Knut Korsbrekke, Jennifer Ann Devine, Jon Egil Skjæraasen
ICES Journal of Marine Science 71 p. 2053-2063
2013

The effect of triploidy on the culture performance, deformity prevalence, and heart morphology in Atlantic salmon

Tom Fraser, Tom Johnny Hansen, Jon Egil Skjæraasen, Ian Mayer, Florian Sambraus, Per Gunnar Fjelldal
Aquaculture 416-417 p. 255-264
2013

Size-, energy- and stage dependent fecundity and atresia in the Northeast Arctic haddock Melanogrammus aeglefinus

Jon Egil Skjæraasen, Knut Korsbrekke, Olav Sigurd Kjesbu, Merete Fonn, Trygve Nilsen, Richard David Marriott Nash
Fisheries Research 138 p. 120-127
2012

Triploidy alters brain morphology in pre-smolt Atlantic salmon Salmo salar: possible implications for behaviour

Tom Fraser, Per Gunnar Fjelldal, Jon Egil Skjæraasen, Tom Johnny Hansen, Ian Mayer
Journal of Fish Biology 81 p. 2199-2212
2012

Secondary sexual characteristics in codfishes (Gadidae) in relation to sound production, habitat use and social behaviour

Jon Egil Skjæraasen, Justin James Meager, Mikko Petteri Heino
Marine Biology Research 8 p. 201-209
2012

Frequent skipped spawning in the world's largest cod population

Jon Egil Skjæraasen, Richard David Marriott Nash, Knut Korsbrekke, Merete Fonn, Trygve Nilsen, James Kennedy, Kjell Harald Nedreaas, Anders Thorsen, Peter R. Witthames, Audrey J. Geffen, Hans Høie, Olav Sigurd Kjesbu
Proceedings of the National Academy of Sciences of the United States of America 109 p. 8995-8999
2012

Multidimensionality of behavioural phenotypes in Atlantic cod, Gadus morhua

Justin James Meager, Anders Fernø, Jon Egil Skjæraasen, Torbjörn Järvi, Petra Rodewald, Gisle Karlsen Sverdrup, Svante Winberg, Ian Mayer
Physiology and Behavior 106 p. 462-470
2012

Environmental regulation of individual depth on a cod spawning ground

Justin James Meager, Jon Egil Skjæraasen, Ørjan Karlsen, Svein Løkkeborg, Ian Mayer, Kathrine Michalsen, Trygve Nilsen, Anders Fernø
Aquatic Biology 17 p. 211-221
2011

Domestication causes rapid changes in heart and brain morphology in Atlantic cod (Gadus morhua)

Ian Mayer, Justin James Meager, Jon Egil Skjæraasen, Petra Rodewald, Gisle Karlsen Sverdrup, Anders Fernø
Environmental Biology of Fishes 92 p. 181-186
2011

Behavioural responses of hatchery-reared and wild cod Gadus morhua to mechano-acoustic predator signals

Justin James Meager, Petra Rodewald, Paolo Domenici, Anders Fernø, Torbjörn Järvi, Jon Egil Skjæraasen, Gisle Karlsen Sverdrup
Journal of Fish Biology 78 p. 1437-1450
2011

The hypoxia avoidance behaviour of juvenile Atlantic cod (Gadus morhua L.) depends on the provision and pressure level of an O2 refuge

Neill A. Herbert, Jon Egil Skjæraasen, Trygve Nilsen, Anne Gro Vea Salvanes, John F. Steffensen
Marine Biology 158 p. 737-746
2011

Evaluation of the frequency of skipped spawning in Norwegian spring-spawning herring

James Kennedy, Jon Egil Skjæraasen, Richard David Marriot Nash, Aril Slotte, Audrey J. Geffen, Olav S. Kjesbu
Journal of Sea Research 65 p. 327-332
2011

Extreme spawning-site fidelity in Atlantic cod

Jon Egil Skjæraasen, Justin James Meager, Ørjan Karlsen, Jeffrey A. Hutchings, Anders Fernø
ICES Journal of Marine Science 68 p. 1472-1477
2011

Territorial and agonistic interactions between escaped farmed and wild cod (Gadus morhua)

Gisle Karlsen Sverdrup, Justin James Meager, Anders Fernø, Jon Egil Skjæraasen, Petra Rodewald, Anne Gro Vea Salvanes, Torbjørn Järvi
Aquaculture Research 42 p. 1539-1548
2010

Mating competition between farmed and wild cod Gadus morhua

Jon Egil Skjæraasen, Justin James Meager, Ørjan Karlsen, Ian Mayer, Geir Dahle, Geir Rudolfsen, Anders Fernø
Marine Ecology Progress Series 412 p. 247-258
2010

A cost of reproduction in male Atlantic cod (Gadus morhua)

Jon Egil Skjæraasen, Justin James Meager, Jeffrey A. Hutchings
Canadian Journal of Zoology 88 p. 595-600
2010

Reproductive interactions between fugitive farmed and wild Atlantic cod (Gadus morhua) in the field

Justin James Meager, Jon Egil Skjæraasen, Anders Fernø, Svein Løkkeborg
Canadian Journal of Fisheries and Aquatic Sciences 67 p. 1221-1231
2010

Shifting reproductive success in a shoal of Atlantic Cod, Gadus morhua L

Jon Egil Skjæraasen, Jeffrey A. Hutchings
Environmental Biology of Fishes 88 p. 311-318
2010

Do capital breeders like Atlantic herring (Clupea harengus) exhibit sensitive periods of nutritional control on ovary development and fecundity regulation?

James Kennedy, Jon Egil Skjæraasen, Richard David Marriot Nash, Anders Thorsen, Aril Slotte, Tom Hansen, Olav Sigurd Kjesbu
Canadian Journal of Fisheries and Aquatic Sciences 67 p. 16-27
2010

Liver energy, atresia and oocyte stage influence fecundity regulation in Northeast Arctic cod

Jon Egil Skjæraasen, Richard David Marriot Nash, James Kennedy, Anders Thorsen, Trygve Nilsen, Olav Sigurd Kjesbu
Marine Ecology Progress Series 404 p. 173-183
2009

Sperm characteristics and competitive ability in farmed and wild cod

Jon E. Skjaeraasen, Jon Egil Skjæraasen, Ian Mayer, I Mayer, Justin J. Meager, Geir Rudolfsen, O Karlsen, Ørjan Karlsen, Thomas Haugland, Oddmund Kleven
Marine Ecology Progress Series 375 p. 219-228
2009

Mechanisms regulating oocyte recruitment and skipped spawning in Northeast Arctic cod (Gadus morhua)

Jon Egil Skjæraasen, James Kennedy, Anders Thorsen, Merete Fonn, Bente Njøs Strand, Ian Mayer, Olav Sigurd Kjesbu
Canadian Journal of Fisheries and Aquatic Sciences 66 p. 1582-1596
2009

Vertical dynamics and reproductive behaviour of farmed and wild Atlantic cod Gadus morhua

Justin James Meager, Jon Egil Skjæraasen, Anders Fernø, Ørjan Karlsen, Svein Løkkeborg, Kathrine Michalsen, Stig Ove Utskot
Marine Ecology Progress Series 389 p. 233-243
2008

The expression of secondary sexual characteristics in recruit- and repeat-spawning farmed and wild Atlantic cod (Gadus morhua)

Jon Egil Skjæraasen, Justin James Meager, Ørjan Karlsen
ICES Journal of Marine Science 65 p. 1710-1716
2008

The Isolation of Atlantic cod, Gadus morhua (Gadiformes), populations in northern meromictic lakes - A recurrent arctic phenomenon

David C Hardie, C B Renaud, VP Ponomarenko, NV Mukhina, Nathalia A. Yaragina, Jon Egil Skjæraasen, Jeffrey A. Hutchings
Journal of Ichthyology 48 p. 230-240
2008

Hypoxic avoidance behaviour in cod (Gadus morhua L.): The effect of temperature and haemoglobin genotype

Jon Egil Skjæraasen, Trygve Nilsen, Justin James Meager, Neill A. Herbert, Olav Moberg, Valentina Tronci, Torild Johansen, Anne Gro Vea Salvanes
Journal of Experimental Marine Biology and Ecology 358 p. 70-77
2008

Morphological and behavioural correlates of reproductive success in Atlantic cod Gadus morhua

Sherrylynn Rowe, Jeffrey A. Hutchings, Jon Egil Skjæraasen, Louise Bezanson
Marine Ecology Progress Series 354 p. 257-265
2007

Nonrandom mating in a broadcast spawner: mate size influences reproductive success in Atlantic cod (Gadus morhua)

Sherrylynn Rowe, Jeffrey A. Hutchings, Jon Egil Skjæraasen
Canadian Journal of Fisheries and Aquatic Sciences 64 p. 219-226
2006

Timing and determination of potential fecundity in Atlantic cod (Gadus morhua)

Jon Egil Skjæraasen, Trygve Nilsen, Olav Sigurd Kjesbu
Canadian Journal of Fisheries and Aquatic Sciences 63 p. 310-320
2006

Sexual dimorphism in pelvic fin length of Atlantic cod

Jon Egil Skjæraasen, S. Rowe, J.A. Hutchings
Canadian Journal of Zoology 84 p. 865-870
2005

Recovery from handling stress in Gadus morhua

Mireia Lara Artigas, Jon Egil Skjæraasen, Anne Christine Utne-Palm, Trygve Nilsen
Journal of Fish Biology 67 p. 384-391
2004

Sub-populations of coastal cod with different behaviour and life-history strategies

Anne Gro Vea Salvanes, Jon Egil Skjæraasen, Trygve Nilsen
Marine Ecology Progress Series 267 p. 241-251
2004

The effect of photoperiod on sexual maturation, appetite and growth in wild atlantic cod (Gadus morhua L)

Jon Egil Skjæraasen, Anne Gro Vea Salvanes, Ørjan Karlsen, Geir Dahle, Trygve Nilsen, Birgitta Norberg
Fish Physiology & Biochemistry 30 p. 163-174
2001

Notes on Raja lintea, R. Hyperborea and Bathyraja spinicauda (Pisces: Rajiade) in the Deep northeastern North Sea and on the slope of the eastern Norwegian Sea

Jon Egil Skjæraasen, Odd Aksel Bergstad
ICES Journal of Marine Science 58 p. 21-28
2000

Trophic ecology of deep-water fishes associated with the continental slope of the eastern Norwegian Sea

Otte Bjelland, Odd Aksel Bergstad, Jon Egil Skjæraasen, Kenneth Meland
Sarsia 85 p. 101-117
2000

Distribution and feeding ecology of starry ray, Raja radiata, in the northeastern North Sea and Skagerrak

Jon Egil Skjæraasen, Odd Aksel Bergstad
ICES Journal of Marine Science 57 p. 1249-1260

Faglige foredrag

2024

Seasonal dynamics in ocean temperatures can give false impression of thermal bottleneck for spawning fish

Anders Martin Frugård Opdal, Christian Jørgensen, Lise Doksæter Sivle, Ørjan Karlsen, Tom Langbehn, Anna Jeja Gabriella Ljungström, Kate McQueen, Mari Skuggedal Myksvoll, Daniel Nyqvist, Esben Moland Olsen, Jon Egil Skjæraasen
2023

SpawnSeis. Påvirkning av luftkanon og marin vibrator på gytende torsk

Lise Doksæter Sivle, Kate McQueen, Karen de Jong, Tonje Nesse Forland, Jon Egil Skjæraasen, Esben Moland Olsen, Ørjan Karlsen
2023

Fine-scale behaviour of Atlantic cod ecotypes

Karl Øystein Gjelland, Esben Moland Olsen, Henrik Baktoft, Thomas Bøhn, John Fredrik Strøm, Jon Egil Skjæraasen, Torild Johansen, Eirik Emil Bygdnes, Pål Arne Bjørn
2022

Atlantic cod facing climate-driven warming: Reproductive physiology under challenging environmental conditions

A. Maud, Lene Kleppe, Eva Andersson, Birgitta Norberg, Ørjan Karlsen, Paul Whatmore, Jorge Manuel de Oliveira Fernandes, Artem Nedoluzhko, Kaja Helvik Skjærven, Jon Egil Skjæraasen, Olav Sigurd Kjesbu
2022

Behavioural responses of spawning Atlantic cod (Gadus morhua) to seismic airgun exposure.

Kate McQueen, Jon Egil Skjæraasen, Daniel Nyqvist, Esben Moland Olsen, Ørjan Karlsen, Justin James Meager, Petter Helgevold Kvadsheim, Nils Olav Handegard, Tonje Nesse Forland, Lise Doksæter Sivle
2020

Fisk gyter ved bestemte temperaturer – atferd eller miljø

Anders Martin Frugård Opdal, Jon Egil Skjæraasen, Christian Jørgensen
2019

Pre-programmed or flexible? Lab and field studies don't add up and suggest strong individual influence on spawning time in Atlantic cod

Anders Frugård Opdal, Christian Jørgensen, Jon Egil Skjæraasen, Olav Sigurd Kjesbu
2019

How will ocean warming affect the reproductive performance of Atlantic cod, Gadus morhua?

Maud Alix, Lene Kleppe, Eva Andersson, Birgitta Norberg, Ørjan Karlsen, Jon Egil Skjæraasen, Olav Sigurd Kjesbu
2018

Interaksjoner mellom lakseoppdrett og gyteområder for torsk (ICOD-prosjektet)

Terje van der Meeren, Jon Egil Skjæraasen, Mari Skuggedal Myksvoll, Geir Dahle, Esben Moland Olsen, Ørjan Karlsen, Raymond Bannister
2018

Interaksjoner mellom lakseoppdrett og gyteområder for torsk (ICOD-prosjektet).

Terje van der Meeren, Jon Egil Skjæraasen, Mari Skuggedal Myksvoll, Geir Dahle, Esben Moland Olsen, Ørjan Karlsen, Raymond Bannister
2018

Interactions of salmon farming on Atlantic cod spawning grounds (ICOD prosjektet).

Terje van der Meeren, Jon Egil Skjæraasen, Mari Skuggedal Myksvoll, Geir Dahle, Esben Moland Olsen, Ørjan Karlsen, Raymond Bannister
2018

Interactions of salmon farming on Atlantic cod spawning grounds.

Terje van der Meeren, Jon Egil Skjæraasen, Mari Skuggedal Myksvoll, Geir Dahle, Esben Moland Olsen, Ørjan Karlsen, Raymond Bannister
2016

ICOD, Interactions of aquaculture with cod spawning grounds

Terje van der Meeren, Raymond Bannister, Jon Egil Skjæraasen, Mari Skuggedal Myksvoll
2016

Gyter torsk nær oppdrettsanlegg?

Mari Skuggedal Myksvoll, Raymond Bannister, Terje van der Meeren, Jon Egil Skjæraasen
2015

Skipped spawning in Northeast Arctic gadoids

Skjæraasen, Jon Egil
2013

A positive outlook for cod in the Barents Sea: Unexpected synergies between climate and management

Olav Sigurd Kjesbu, Bjarte Bogstad, A. Jennifer Devine, Harald Gjøsæter, Daniel Howell, Randi Brunvær Ingvaldsen, Richard David Marriott Nash, Jon Egil Skjæraasen
2013

A positive outlook for cod in the Barents Sea: Synergies between climate and management

Olav Sigurd Kjesbu, Bjarte Bogstad, Jennifer Ann Devine, Harald Gjøsæter, Daniel Howell, Randi Ingvaldsen, Richard David Marriott Nash, Jon Egil Skjæraasen
2013

Is spawning success of Atlantic cod escapees influenced by differences in sperm competition?

Ian Mayer, Justin James Meager, Jon Egil Skjæraasen, Geir Rudolfsen, Ørjan Karlsen, Olav Moberg, Arved Staby, Oddmund Kleven, Anders Fernö
2013

Skipped spawning in female Northeast Arctic gadoids

Jon Egil Skjæraasen, Knut Korsbrekke, Richard David Marriott Nash, Olav Sigurd Kjesbu
2012

Will farmed escapees hybridize with wild cod populations?

Jon Egil Skjæraasen, Justin James Meager, Anders Fernö
2012

Interbreeding between farmed escapees and wild cod

Jon Egil Skjæraasen, Justin James Meager, A. Fernö
2012

Effects of spawning history on growth of Northeast Arctic cod (Gadus morhua L.)

Arild Folkvord, Hans Høie, Christian Jørgensen, Knut Korsbrekke, Richard David Marriott Nash, Trygve Nilsen, Jon Egil Skjæraasen
2011

Temperature, fish size, spawning time and reproductive success of Atlantic cod

Olav Sigurd Kjesbu, Jon Egil Skjæraasen, Francisco Rey, Christian Jørgensen
2011

Spawning omission and fecundity regulation in the Northeast Arctic haddock (Melanogrammus aeglefinus)

Jon Egil Skjæraasen, Knut Korsbrekke, Merete Fonn, Olav Sigurd Kjesbu, Richard David Marriott Nash
2011

The link between temperature, fish size, spawning time and reproductive success of Atlantic cod

Olav Sigurd Kjesbu, Jon Egil Skjæraasen, Francisco Rey, Christian Jørgensen
2011

Sperm traits and reproductive roles in a marine broadcast spawner

Jon Egil Skjæraasen, Justin James Meager, Geir Rudolfsen, Ørjan Karlsen, Ian Mayer, Olav Moberg, Arved Staby, Geir Dahle, Anders Fernø
2010

Climate-linked effects on maturation and spawning of Atlantic cod and implications for fisheries

Olav Sigurd Kjesbu, Jon Egil Skjæraasen, D Righton, Kathrine Michalsen, Christian Jørgensen, Anders Frugård Opdal, Peter R. Witthames
2009

Does skipped spawning occur for cod and herring?

Jon Egil Skjæraasen, Olav Sigurd Kjesbu
2009

Is sperm competition a major component of sexual selection in Atlantic cod?

Ian Mayer, Jon Egil Skjæraasen, Justin James Meager, Geir Rudolfsen, Ørjan Karlsen, Olav Moberg, Arved Staby, Oddmund Kleven
2009

From “where” and “when” to “what” and “why”: archival tags for monitoring “complex” behaviours in fish

Julian D. Metcalfe, RP Wilson, Olav Sigurd Kjesbu, MJ Challiss, A Gleiss, Jon Egil Skjæraasen, S Clarke
2009

The risk of genetic introgression from farmed escapees to wild cod populations

Jon Egil Skjæraasen, Justin James Meager, A. Ferno
2008

Mating competition between farmed and wild cod

Jon Egil Skjæraasen, Justin James Meager, Ørjan Karlsen, Ian Mayer, Geir Rudolfsen, Geir Dahle, A. Fernö
2008

Movements and behaviour of escaped farmed cod (Gadus morhua) on a spawning ground

Justin James Meager, Jon Egil Skjæraasen, Anders Fernö, Ørjan Karlsen, Svein Løkkeborg
2008

Induction of skipped spawning in herring

James Kennedy, Jon Egil Skjæraasen, Richard David Marriott Nash, Anders Thorsen, Aril Slotte, Olav Sigurd Kjesbu
2008

Determinants of sperm competition and the role of cryptic female choice in the broadcast spawning Atlantic cod (Gadus morhua)

Ian Mayer, Jon Egil Skjæraasen, Justin James Meager, Geir Rudolfsen, Ørjan Karlsen, Olav Moberg, Arved Staby, Oddmund Kleven, Anders Fernö
2008

Assessment of the occurrence and dynamics of skipped spawning in Norwegian spring-spawning herring (Clupea harengus)

James Kennedy, Jon Egil Skjæraasen, Richard David Marriott Nash, Anders Thorsen, Aril Slotte, Olav Sigurd Kjesbu
2008

Movement and behaviour of escaped farmed cod (Gadus morhua L)

Justin James Meager, Jon Egil Skjæraasen, Anders Fernö, Svein Løkkeborg, Ørjan Karlsen, Kathrine Michalsen
2007

Timing and fecundity determination in Norwegian Spring Spawning herring

James Kennedy, Olav Sigurd Kjesbu, Maria Krüger-Johnsen, Hilkka Opolili Ndahafa Ndjaula, Jon Egil Skjæraasen, Aril Slotte, Anders Thorsen
2007

Movements and behaviour of escaped farmed cod on a spawning ground

Justin James Meager, Jon Egil Skjæraasen, Anders Fernö, Svein Løkkeborg, Ørjan Karlsen, Kathrine Michalsen
2007

Timing and determination of fecundity and skipped spawning in Atlantic cod

Jon Egil Skjæraasen, James Kennedy, Anders Thorsen, Richard David Marriott Nash, Olav Sigurd Kjesbu
2007

Timing and determination of skipped spawning in Atlantic cod

Jon Egil Skjæraasen, James Kennedy, Anders Thorsen, Richard David Marriott Nash, Olav Sigurd Kjesbu
2005

Timing and determination of potential fecundity in Atlantic cod

Jon Egil Skjæraasen, Trygve Nilsen

Poster

2019

From oogenesis to embryonic development: How climate change may affect reproductive performance of Atlantic cod

Maud Alix, Lene Kleppe, Eva Andersson, Birgitta Norberg, Ørjan Karlsen, Anders Thorsen, Jon Egil Skjæraasen, Olav Sigurd Kjesbu
2019

Do seismic surveys affect the behavior of spawning cod?

Daniel Nyqvist, Lise Doksæter Sivle, Ørjan Karlsen, Esben Moland Olsen, Karen de Jong, Tonje Nesse Forland, Jon Egil Skjæraasen
2019

Behaviour of spawning cod in relation to marine seismic surveys

Daniel Nyqvist, Lise Doksæter Sivle, Ørjan Karlsen, Esben Moland Olsen, Karen de Jong, Tonje Nesse Forland, Jon Egil Skjæraasen
2017

The influence of salmon Salmo salar aquaculture on spawning ground use of Atlantic cod Gadus morhua.

Jon Egil Skjæraasen, Ørjan Karlsen, Esben Moland Olsen, Even Moland, Kristine Marit Schrøder Elvik, Terje van der Meeren, Raymond Bannister
2014

Energy allocation patterns associated with reproduction in Northeast Arctic gadoids

Jon Egil Skjæraasen, Jennifer A Devine, Anders Frugård Opdal, Knut Korsbrekke, Christian Jørgensen
2014

Aspects of the European hake ecology in the North Sea and Norwegian waters

Arved Staby, Jon Egil Skjæraasen
2013

The use of triploid salmon in Norwegian Aquaculture

Thomas WK Fraser, Tom Johnny Hansen, Ian Mayer, Kevin A. Glover, Jon Egil Skjæraasen, Vidar Wennevik, Robin Ørnsrud, Florian Sambraus, Per Gunnar Fjelldal
2013

The use of triploid salmon in Norwegian Aquaculture

Thomas WK Fraser, Tom Johnny Hansen, Ian Mayer, Jon Egil Skjæraasen, Robin Ørnsrud, Florian Sambraus, Per Gunnar Fjelldal
2013

Radiological studies on vertebral deformities in triploid Atlantic salmon (Salmo salar)

Thomas WK Fraser, Tom Johnny Hansen, M. Fleming, Florian Sambraus, Ian Mayer, Jon Egil Skjæraasen, Anna Wargelius, Robin Ørnsrud, Erik-Jan Lock, Per Gunnar Fjelldal
2013

Does triploidy affect brain morphology and neurochemistry in Atlantic salmon, Salmo salar?

Thomas WK Fraser, Joel Glover, Marco A. Vindas, Øyvind Øverli, Jon Egil Skjæraasen, Tom Johnny Hansen, Per Gunnar Fjelldal, Ian Mayer
2011

Skipped spawning in Northeast Arctic gadoids

Jon Egil Skjæraasen, Knut Korsbrekke, Olav Sigurd Kjesbu, Richard David Marriott Nash
2009

The incidence of skipped spawning in Northeast Arctic gadoids

Jon Egil Skjæraasen, James Kennedy, Richard David Marriott Nash, Anders Thorsen, Olav Sigurd Kjesbu
2008

Sperm competition in farmed and wild cod

Jon Egil Skjæraasen, Ian Mayer, Justin James Meager, Geir Rudolfsen, Thomas Haugland, Ørjan Karlsen, Oddmund Kleven
2007

Frequency of skipped spawning in Norwegian spring-spawning herring

James Kennedy, Jon Egil Skjæraasen, Richard David Marriott Nash, Aril Slotte, Olav Sigurd Kjesbu
2007

The cod mating system and the risk of genetic introgression from farmed escapees

Jon Egil Skjæraasen, Justin James Meager, Ørjan Karlsen, Svein Løkkeborg, Kathrine Michalsen, Ian Mayer, Jeffrey A. Hutchings, Anders Fernö
2006

The effect of parental hemoglobin genotype and temperature on hatching and survival of Norwegian coastal cod larvae

Olaf Selmer Aarsheim, Jon Egil Skjæraasen, Anne Gro Vea Salvanes
2006

The cod mating system-a lekking “broadcast spawner”

Jon Egil Skjæraasen, Sherrylynn Rowe, Jeffrey A. Hutchings, Anne Gro Vea Salvanes, Geir Dahle
2002

Reproductive behaviour and paternity in Atlantic Cod (Gadus morhua)

Jon Egil Skjæraasen, Anne Gro Vea Salvanes
2001

Feeding behaviour of one year old Atlantic cod (Gadus morhua); the effect of predation

Jon Egil Skjæraasen, Anne Gro Salvanes
1999

Distribution and feeding ecology of skates in the northeastern North Sea and Skagerrak

Jon Egil Skjæraasen, Odd Aksel Bergstad

Rapporter og avhandlinger

2023

Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak (WGNSSK)

Jurgen Batsleer, Alan Baudron, Chun Chen, Harriet S. Cole, José A.A. De Oliveira, Côme Denechaud, Raphael Girardin, Ghassen Halouani, Holger Haslob, Alexander Holdgate, Nis Sand Jacobsen, Alexander Kempf, Alexandros Kokkalis, Eleni Melis, Carlos Mesquita, Tanja Miethe, Iago Mosqueira, Nikolai Nawri, Coby Needle, J. Rasmus Nielsen, Alessandro Orio, Yves Reecht, Jon Egil Skjæraasen, Guldborg Søvik, Klaas Sys, Marc Taylor, Justin Tiano, Lies Vansteenbrugge, Damian Villagra Villanueva, Bella Voak, Kathrin Vossen, Nicola Walker
ICES Scientific Reports 5
2021

Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak (WGNSSK)

Anja Helene Alvestad, Jurgen Batsleer, Alan Baudron, Katinka Bleeker, Aaron Brazier, Chun Chen, José A.A. De Oliveira, Raphael Girardin, Ghassen Halouani, Holger Haslob, Alexander Kempf, Alexandros Kokkalis, Carlos Mesquita, Tanja Miethe, Iago Mosqueira, Nikolai Nawri, Coby Needle, Anders Nielsen, J. Rasmus Nielsen, Alessandro Orio, Alfonso Perez-Rodriguez, Yves Reecht, Jon Egil Skjæraasen, Guldborg Søvik, Andreas Sundelöf, Klaas Sys, Marc Taylor, Sebastian Uhlmann, Mats Ulmestrand, Mikael Van Deurs, Lies Vansteenbrugge, Tiago Veiga-Malta, Francesca Vitale, Nicola Walker, Fabian Zimmermann
ICES Scientific Reports 3
2021

ICES. 2021. Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak (WGNSSK)

Anja Helene Alvestad, Jurgen Batsleer, Alan Baudron, Katinka Bleeker, Aaron Brazier, Chun Chen, José A.A. De Oliveira, Raphael Girardin, Ghassen Halouani, Holger Haslob, Alexander Kempf, Alexandros Kokkalis, Carlos Mesquita, Tanja Miethe, Iago Mosqueira, Nikolai Nawri, Coby Needle, Anders Nielsen, J. Rasmus Nielsen, Alessandro Orio, Alfonso Perez-Rodriguez, Yves Reecht, Jon Egil Skjæraasen, Guldborg Søvik, Andreas Sundelöf, Klaas Sys, Marc Taylor, Sebastian Uhlmann, Mats Ulmestrand, Mikael Van Deurs, Lies Vansteenbrugge, Tiago Veiga-Malta, Francesca Vitale, Nicola Walker, Fabian Zimmermann
2021

Sluttrapport fra ICOD-prosjektet - Arbeidspakke 2: Egg- og yngelundersøkelser på gyte- og oppvekstområder på Smøla og i Aure i forbindelse med etablering av oppdrettsanlegg nær lokale gyteområder for kysttorsk

Terje van der Meeren, Sonnich Meier, Mari Skuggedal Myksvoll, Geir Dahle, Ørjan Karlsen, Arved Staby, Hildegunn Mjanger, Annhild Engevik, Katherine Mary Dunlop, Raymond Bannister, Jon Egil Skjæraasen
2003

Environmental influence on fish stocks

Anne Gro Salvanes, Dag Lorents Aksnes, Folkvord Arild, Mette Hordnes, Hans Ingolf Høie, Frank Midtøy, Jens Christian Nejstgaard, Erling Otterlei, Jon Egil Skjæraasen, Tom Asbjørn Sørnes, Anne Christine Utne-Palm
2003

Implications of behaviour for maturation and spawning in cod

Skjæraasen, Jon Egil
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