Jon Egil Skjæraasen
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
Sex-specific vertical movements of spawning atlantic cod in coastal habitats inferred from acoustic telemetry
Scientific Reports
14
p. 23242
2024
Ecological interactions between farmed Atlantic salmon and wild Atlantic cod populations in Norway: A review of risk sources and knowledge gaps
Reviews in Aquaculture
2024
Continuous sound from a marine vibrator causes behavioural responses of free-ranging, spawning Atlantic cod (Gadus morhua)
Environmental Pollution (1987)
344
2023
Large females connect Atlantic cod spawning sites
Science
382
p. 1181-1184
2023
Large females connect Atlantic cod spawning sites
Science
382
p. 1181-1185
2023
Movement diversity and partial sympatry of coastal and Northeast Arctic cod ecotypes at high latitudes
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)
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)
ICES Journal of Marine Science
80
p. 1143-1154
2023
Behavioural responses of wild, spawning Atlantic cod (Gadus morhua L.) to seismic airgun exposure
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
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).
ICES Journal of Marine Science
2022
Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak (WGNSSK)
ICES Scientific Reports
4
2022
Habitat associations of juvenile Atlantic cod (Gadus morhua L.) and sympatric demersal fish communities within shallow inshore nursery grounds
Estuarine, Coastal and Shelf Science
279
2022
Attraction of cod Gadus morhua from coastal spawning grounds to salmon farms
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
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)
ICES Scientific Reports
4
2021
Highly mixed impacts of near-future climate change on stock productivity proxies in the North East Atlantic
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
Aquaculture
540
2021
Impact of salmon farming on Atlantic cod spatio-temporal reproductive dynamics
Aquaculture Environment Interactions
13
p. 399-412
2021
Genetic structuring in Atlantic haddock contrasts with current management regimes
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
Fisheries Research
230
2018
Spatial and temporal dynamics of European hake (Merluccius merluccius) in the North Sea
ICES Journal of Marine Science
76
p. 2033-2044
2018
Vertebral column deformity in adult wild haddock(Melanogrammus aeglefinus)
Journal of Fish Diseases
41
p. 1909-1915
2018
Multi-decadal variations in spawning ground use in Northeast Arctic haddock (Melanogrammus aeglefinus)
Fisheries Oceanography
27
p. 435-444
2017
The behavioural diversity of Atlantic cod: insights into variability within and between individuals
Reviews in Fish Biology and Fisheries
28
p. 153-176
2017
Timecourse of oocyte development in saithe Pollachius virens
Journal of Fish Biology
90
p. 109-128
2015
Skipped spawning in Northeast Arctic haddock Melanogrammus aeglefinus
Marine Ecology Progress Series
526
p. 143-155
2015
Increased reactivity and monoamine dysregulation following stress in triploid Atlantic salmon (Salmo salar)
Comparative Biochemistry and Physiology A
185
p. 125-131
2015
Vaccination and triploidy increase relative heart weight in farmed Atlantic salmon, Salmo salar L
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
Aquaculture International
22
p. 1347-1359
2014
Trade-offs between growth and reproduction in wild Atlantic cod
Canadian Journal of Fisheries and Aquatic Sciences
71
p. 1106-1112
2014
The effect of triploidy on vaccine side-effects in Atlantic salmon
Aquaculture
433
p. 481-490
2014
Synergies between climate and management for Atlantic cod fisheries at high latitudes
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
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
Aquaculture
416-417
p. 255-264
2013
Size-, energy- and stage dependent fecundity and atresia in the Northeast Arctic haddock Melanogrammus aeglefinus
Fisheries Research
138
p. 120-127
2012
Triploidy alters brain morphology in pre-smolt Atlantic salmon Salmo salar: possible implications for behaviour
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
Marine Biology Research
8
p. 201-209
2012
Frequent skipped spawning in the world's largest cod population
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
Physiology and Behavior
106
p. 462-470
2012
Environmental regulation of individual depth on a cod spawning ground
Aquatic Biology
17
p. 211-221
2011
Domestication causes rapid changes in heart and brain morphology in Atlantic cod (Gadus morhua)
Environmental Biology of Fishes
92
p. 181-186
2011
Behavioural responses of hatchery-reared and wild cod Gadus morhua to mechano-acoustic predator signals
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
Marine Biology
158
p. 737-746
2011
Evaluation of the frequency of skipped spawning in Norwegian spring-spawning herring
Journal of Sea Research
65
p. 327-332
2011
Extreme spawning-site fidelity in Atlantic cod
ICES Journal of Marine Science
68
p. 1472-1477
2011
Territorial and agonistic interactions between escaped farmed and wild cod (Gadus morhua)
Aquaculture Research
42
p. 1539-1548
2010
Mating competition between farmed and wild cod Gadus morhua
Marine Ecology Progress Series
412
p. 247-258
2010
A cost of reproduction in male Atlantic cod (Gadus morhua)
Canadian Journal of Zoology
88
p. 595-600
2010
Reproductive interactions between fugitive farmed and wild Atlantic cod (Gadus morhua) in the field
Canadian Journal of Fisheries and Aquatic Sciences
67
p. 1221-1231
2010
Shifting reproductive success in a shoal of Atlantic Cod, Gadus morhua L
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?
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
Marine Ecology Progress Series
404
p. 173-183
2009
Sperm characteristics and competitive ability in farmed and wild cod
Marine Ecology Progress Series
375
p. 219-228
2009
Mechanisms regulating oocyte recruitment and skipped spawning in Northeast Arctic cod (Gadus morhua)
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
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)
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
Journal of Ichthyology
48
p. 230-240
2008
Hypoxic avoidance behaviour in cod (Gadus morhua L.): The effect of temperature and haemoglobin genotype
Journal of Experimental Marine Biology and Ecology
358
p. 70-77
2008
Morphological and behavioural correlates of reproductive success in Atlantic cod Gadus morhua
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)
Canadian Journal of Fisheries and Aquatic Sciences
64
p. 219-226
2006
Timing and determination of potential fecundity in Atlantic cod (Gadus morhua)
Canadian Journal of Fisheries and Aquatic Sciences
63
p. 310-320
2006
Sexual dimorphism in pelvic fin length of Atlantic cod
Canadian Journal of Zoology
84
p. 865-870
2005
Recovery from handling stress in Gadus morhua
Journal of Fish Biology
67
p. 384-391
2004
Sub-populations of coastal cod with different behaviour and life-history strategies
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)
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
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
Sarsia
85
p. 101-117
2000
Distribution and feeding ecology of starry ray, Raja radiata, in the northeastern North Sea and Skagerrak
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
2023
SpawnSeis. Påvirkning av luftkanon og marin vibrator på gytende torsk
2023
Fine-scale behaviour of Atlantic cod ecotypes
2022
Atlantic cod facing climate-driven warming: Reproductive physiology under challenging environmental conditions
2022
Behavioural responses of spawning Atlantic cod (Gadus morhua) to seismic airgun exposure.
2020
Fisk gyter ved bestemte temperaturer – atferd eller miljø
2019
Pre-programmed or flexible? Lab and field studies don't add up and suggest strong individual influence on spawning time in Atlantic cod
2019
How will ocean warming affect the reproductive performance of Atlantic cod, Gadus morhua?
2018
Interaksjoner mellom lakseoppdrett og gyteområder for torsk (ICOD-prosjektet)
2018
Interaksjoner mellom lakseoppdrett og gyteområder for torsk (ICOD-prosjektet).
2018
Interactions of salmon farming on Atlantic cod spawning grounds (ICOD prosjektet).
2018
Interactions of salmon farming on Atlantic cod spawning grounds.
2016
ICOD, Interactions of aquaculture with cod spawning grounds
2016
Gyter torsk nær oppdrettsanlegg?
2015
Skipped spawning in Northeast Arctic gadoids
2013
A positive outlook for cod in the Barents Sea: Unexpected synergies between climate and management
2013
A positive outlook for cod in the Barents Sea: Synergies between climate and management
2013
Is spawning success of Atlantic cod escapees influenced by differences in sperm competition?
2013
Skipped spawning in female Northeast Arctic gadoids
2012
Will farmed escapees hybridize with wild cod populations?
2012
Interbreeding between farmed escapees and wild cod
2012
Effects of spawning history on growth of Northeast Arctic cod (Gadus morhua L.)
2011
Temperature, fish size, spawning time and reproductive success of Atlantic cod
2011
Spawning omission and fecundity regulation in the Northeast Arctic haddock (Melanogrammus aeglefinus)
2011
The link between temperature, fish size, spawning time and reproductive success of Atlantic cod
2011
Sperm traits and reproductive roles in a marine broadcast spawner
2010
Climate-linked effects on maturation and spawning of Atlantic cod and implications for fisheries
2009
Does skipped spawning occur for cod and herring?
2009
Is sperm competition a major component of sexual selection in Atlantic cod?
2009
From “where” and “when” to “what” and “why”: archival tags for monitoring “complex” behaviours in fish
2009
The risk of genetic introgression from farmed escapees to wild cod populations
2008
Mating competition between farmed and wild cod
2008
Movements and behaviour of escaped farmed cod (Gadus morhua) on a spawning ground
2008
Induction of skipped spawning in herring
2008
Determinants of sperm competition and the role of cryptic female choice in the broadcast spawning Atlantic cod (Gadus morhua)
2008
Assessment of the occurrence and dynamics of skipped spawning in Norwegian spring-spawning herring (Clupea harengus)
2008
Movement and behaviour of escaped farmed cod (Gadus morhua L)
2007
Timing and fecundity determination in Norwegian Spring Spawning herring
2007
Movements and behaviour of escaped farmed cod on a spawning ground
2007
Timing and determination of fecundity and skipped spawning in Atlantic cod
2007
Timing and determination of skipped spawning in Atlantic cod
2005
Timing and determination of potential fecundity in Atlantic cod
Poster
2019
From oogenesis to embryonic development: How climate change may affect reproductive performance of Atlantic cod
2019
Do seismic surveys affect the behavior of spawning cod?
2019
Behaviour of spawning cod in relation to marine seismic surveys
2017
The influence of salmon Salmo salar aquaculture on spawning ground use of Atlantic cod Gadus morhua.
2014
Energy allocation patterns associated with reproduction in Northeast Arctic gadoids
2014
Aspects of the European hake ecology in the North Sea and Norwegian waters
2013
The use of triploid salmon in Norwegian Aquaculture
2013
The use of triploid salmon in Norwegian Aquaculture
2013
Radiological studies on vertebral deformities in triploid Atlantic salmon (Salmo salar)
2013
Does triploidy affect brain morphology and neurochemistry in Atlantic salmon, Salmo salar?
2011
Skipped spawning in Northeast Arctic gadoids
2009
The incidence of skipped spawning in Northeast Arctic gadoids
2008
Sperm competition in farmed and wild cod
2007
Frequency of skipped spawning in Norwegian spring-spawning herring
2007
The cod mating system and the risk of genetic introgression from farmed escapees
2006
The effect of parental hemoglobin genotype and temperature on hatching and survival of Norwegian coastal cod larvae
2006
The cod mating system-a lekking “broadcast spawner”
2002
Reproductive behaviour and paternity in Atlantic Cod (Gadus morhua)
2001
Feeding behaviour of one year old Atlantic cod (Gadus morhua); the effect of predation
1999
Distribution and feeding ecology of skates in the northeastern North Sea and Skagerrak
Rapporter og avhandlinger
2023
Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak (WGNSSK)
ICES Scientific Reports
5
2021
Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak (WGNSSK)
ICES Scientific Reports
3
2021
ICES. 2021. Working Group on the Assessment of Demersal Stocks in the North Sea and Skagerrak (WGNSSK)
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
2003
Environmental influence on fish stocks
2003
Implications of behaviour for maturation and spawning in cod
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