Sigurd Stefansson's picture

Sigurd Stefansson

  • E-mailSigurd.Stefansson@uib.no
  • Phone+47 55 58 44 70+47 930 84 646
  • Visitor Address
    Thormøhlens gate 53 A/B
    5006 Bergen
  • Postal Address
    Postboks 7803
    5020 Bergen

Professor Sigurd O. Stefansson (December, 2017 ISI statistic 158, H-index 43) has long-term research experience in fish growth and development, reproduction and adaptation to the environment, both in salmonids and marine species, using a wide range of tools. Central in Stefansson’s research is the process of salmon smoltification, and his research includes both basic research and collaboration with the aquaculture industry. Research topics include the environmental, genetic and endocrine control of smoltification and basic mechanisms of adaptation to seawater.

Professional experience

Institute of Marine Research (IMR), Matre Aquaculture Station, Research fellow, Norwegian Fisheries Research Council 'Miljøforholdene i settefisk­produksjon', 07.1986 - 08.1988

Dept. of Fisheries Biology, UiB, Associate Professor (Amanuensis), 08.1988 - 06.1990

IMR, Matre Aquaculture Station, Senior Scientists, 01.07. - 31.12.1990

Dept. of Fisheries and Marine Biology, UiB, Associate professor 12.1990 – 03.2001

Department of Fisheries and Oceans, Biological Station, St. Andrews, Canada, post-doc. (Norwegian Fisheries Research Council), 05. - 12.1992

Dept. of Biology, UiB, Professor, 01.04.2001 – present

Univ. of Massachusetts at Amherst and Conte Anadromous Fish Research Center, Turners Falls, MA, USA, Sabbatical, 08.2003 – 07.2004

Completed Univ. of Bergen programme on teaching and pedagocics, 1994

Member of Dept. of Biology programme board for teaching (several appointments)

Chair of Education, Dept. of Biology, 2016

Chair of WP1 bioCEED, 2016

Head of the study programme “Havbruk og Sjømat” (Aquaculture and Seafood), 2016 – ongoing (integrated master/siv. ing.)


BIF 100 Innføring i fiskehelse og havbruk

Course responsible, teaching, assessment, quality assurance

BIF 101 Organismal Biology in Aquatic Medicine and Aquaculture

Course responsible, teaching, assessment, quality assurance

BIO 104 Comparative physiology

Course responsible, teaching, assessment, quality assurance

BIO 203 Introduction to Aquaculture

Teaching, assessment, quality assurance

BIO 291 Fish Biology II - Fish Physiology

Teaching, assessment, quality assurance

BIO 304 Specialisation in Aquaculture Biology

Teaching, assessment, quality assurance


Cand. scient. and Master students:

43 students completed their degree, 3 currently under supervision

Dr. scient and PhD students:

12 students completed their degree, 3 students currently under supervision

Post-doc researchers:

3 finished

Selected publications (2013-2017)


Imsland, A.K.D., Roth, B., Fjelldal, P.G., Stefansson, S.O., Handeland, S. and Mikalsen, B., 2017. The effect of continuous light at low temperatures on growth in Atlantic salmon reared in commercial size sea pens. Aquaculture, 479, 645-651. DOI: 10.1016/j.aquaculture.2017.07.014

Moore L. J., Nilsen T. O., Jarungsriapisit J., Fjelldal P. G., Stefansson S. O., Taranger G. L. and Patel, S., 2017. Triploid Atlantic salmon (Salmo salar L.) post-smolts accumulate prevalence more slowly than diploid salmon following bath challenge with salmonid alphavirus subtype 3. PLoS ONE 12(4): e0175468. https://doi.org/10.1371/journal.pone.0175468

Moore, L. J., Jarungsriapisit, J., Nilsen, T. O., Stefansson, S., Taranger, G. L., Secombes, C. J., Morton, H. C. and Patel, S., 2017. Immune gene profiles in Atlantic salmon (Salmo salar L.) post-smolts infected with SAV3 by bath-challenge show a delayed response and lower levels of gene transcription compared to injected fish. Fish and Shellfish Immunology, 62, 320-331.

Calabrese, S., T.O.  Nilsen, J. Kolarevic, L.O.E. Ebbesson, C. Pedrosa, S. Fivelstad, C. Hosfeld, S.O. Stefansson, B.F. Terjesen, H. Takle, C.I.M. Martins, H. Sveier, F. Mathisen, A.K. Imsland and S.O. Handeland, 2017. Stocking density limits for post-smolt Atlantic salmon (Salmo salar L.) with emphasis on production performance and welfare. Aquaculture, 468, 363-370. DOI: 10.1016/j.aquaculture.2016.10.041


Imsland, A. K., K. Pettersen and S. O. Stefansson, 2016. Growth and  smoltification of three Norwegian strains of Atlantic salmon reared under different thermal regimes. River Res. Applic., 32, 1800–1807. DOI: 10.1002/rra.3011

Døskeland, I., Imsland, A. K., Fjelldal, P. G., Stefansson, S. O., Roth, B., Eriksen, K. E., Mikalsen, B. and Handeland, S. O., 2016. The effect of low temperatures and photoperiods on growth and vertebra morphometry in Atlantic salmon. Aquacult. Int., 24,1421–1434. DOI 10.1007/s10499-016-9999-7

Jarungsriapisit, J., L. J. Moore, G. L. Taranger, T. O. Nilsen, H. C. Morton, I. U. Fiksdal, S. Stefansson, P. G. Fjelldal, Ø. Evensen and S. Patel, 2016. Atlantic salmon (Salmo salar L.) post-smolts challenged two or nine weeks after seawater-transfer show differences in their susceptibility to salmonid alphavirus subtype 3 (SAV3) Virology Journal, 13 Article Number 66 DOI: 10.1186/s12985-016-0520-8

Vikingstad, E., Andersson, E., Hansen, T. J., Norberg, B., Mayer, I., Stefansson, S. O., Fjelldal, P. G. and Taranger, G. L., 2016. Effects of temperature on the final stages of sexual maturation in Atlantic salmon (Salmo salar L.). Fish Physiol. Biochem. 42,.895-907. DOI: 10.1007/s10695-015-0183-1

Angotzi, A.R, S. O. Stefansson, T. O. Nilsen, J. I. Øvrebø, E. Andersson, G. L. Taranger and I. Rønnestad, 2016. Identification of a novel leptin receptor duplicate in Atlantic salmon: Expression analyses in different life stages and in response to feeding status. Gen. Comp. Endocrinol., 235, 108-119, http://dx.doi.org/10.1016/j.ygcen.2016.06.004

Sveen, L. R., Timmerhaus, G., Torgersen, J. S., Ytteborg, E., Jørgensen, S. M., Handeland, S., Stefansson, S. O., Nilsen, T. O., Calabrese, S., Ebbesson, L., Terjesen, B. F. and Takle, H., 2016, Impact of fish density and specific water flow on skin properties in Atlantic salmon (Salmo salar L.) post-smolts, Aquaculture, 00, 000-000, doi: 10.1016/j.aquaculture.2016.08.012


Salmerón, C., Johansson, M., Asaada,M., Angotzi, A.R., Rønnestad, I., Stefansson, S. O., Jönsson, E., Björnsson, B. Th., Gutiérrez, J., Navarro, I. and Capilla, E., 2015. Roles of leptin and ghrelin in adipogenesis and lipid metabolism of rainbow trout adipocytes in vitro. Comp. Biochem. Physiol., A 188, 40-48. doi:org/10.1016/j.cbpa.2015.06.017


Sundh, H., Nilsen, T.O., Lindström, J., Hasselberg-Frank, L., Stefansson, S.O., McCormick, S.D., Sundell, K. (2014). Development of intestinal transport mechanisms during smoltification in Atlantic salmon smoltification and acclimation to seawater. J. Fish Biol. 85, 1227-1252. doi:10.1111/jfb.12531

Handeland, S.O., Imsland, A.K., Nilsen, T.O., Ebbesson, L.O.E., Hosfeld, C.D., Pedrosa, C., Stefansson, S.O., (2014). Osmoregulation in wild Atlantic salmon smolts transferred to seawater at different temperatures. J. Fish Biol., 85, 1163-1176. doi:10.1111/jfb.12481

Einarsdóttir, I.E., Gong, N., Jönsson-Bergman, E., Sundh, H., Hasselberg Frank, L., Nilsen, T.O., Stefansson, S.O., Sundell, K., Björnsson, B.Th., (2014). Plasma growth hormone binding protein levels in Atlantic salmon (Salmo salar L.) during smoltification and seawater transfer. J. Fish Biol. 85, 1279-1296. doi: 10.1111/jfb.12473

Imsland, AK, Handeland, SO and Stefansson, SO, 2014. Photoperiod and temperature effects on growth and maturation of pre- and post-smolt Atlantic salmon. Aquaculture International, 22, 1331-1345. doi: 10.1007/s10499-014-9750-1

Handeland, SO, Imsland, AK, Ebbesson, LOE, Nilsen, TO, Hosfeld, CD, Teien, HC and Stefansson, SO, 2014. Osmoregulation and growth in offspring of wild Atlantic salmon at different temperatures. Env. Biol. Fishes, 97, 285-296. doi: 10.1007/s10641-013-0151-5


Nilsen, TO, LOE Ebbesson, SO Handeland, F Kroglund, B Finstad, AR Angotzi, SO Stefansson, 2013. Atlantic salmon (Salmo salar L.) smolts require more than two weeks to recover from acidic water and aluminum exposure. Aquatic Toxicol., 142, 33-44. doi.org/10.1016/j.aquatox.2013.07.016

Imsland, A. K., Handeland, S. O., Björnsson, B. Th. and Stefansson, S. O., 2013. Long-term effects of photoperiod and temperature and their interaction on growth, gill Na+,K+-ATPase activity, seawater tolerance and plasma growth hormone levels in Atlantic salmon. J. Fish Biol., 83, 1197-1209

Grassie, C., V.A. Braithwaite, J. Nilsson, T.O. Nilsen, H-C. Teien, S.O. Handeland, S.O. Stefansson, V. Tronci, M. Gorissen, G. Flik & L.O.E. Ebbesson, 2013. Aluminum exposure impacts brain plasticity and behavior in Atlantic salmon (Salmo salar). J. Exp. Biol., 216, 3148-3155, doi:10.1242/jeb.083550

Angotzi, A. R., Stefansson, S., Nilsen, T. O., Rathore, R. M. and Rønnestad, I. 2013. Molecular cloning and genomic characterization of novel Leptin-like genes in salmonids provide new insight into the evolution of the Leptin gene family. Gen. Comp. Endocrinol., 187, 48-59, doi: 10.1016/j.ygcen.2013.03.022  

Handeland, S. O., Imsland, A. K., Ebbesson, L. O. E., Nilsen, T. O., Hosfeld, C. D., Teien, H. C. and Stefansson, S. O., 2013. Osmoregulation and growth in offspring of wild Atlantic salmon at different temperatures. Environmental Biology of Fishes, 97, 285-296.

Handeland, S. O., Imsland, A. K., Ebbesson, L. O. E., Nilsen, T. O., Hosfeld, C. D., Baeverfjord, G., Espmark, Å., Rosten, T., Skilbrei, O. T., Hansen, T., Gunnarsson, G. S., Breck, O. and Stefansson, S. O., 2013. Low light intensity can reduce Atlantic salmon smolt quality. Aquaculture, 384-387, 19-24. doi: org/10.1016/j.aquaculture.2012.12.016

Handeland, S. O., Imsland, A. K, Björnsson, B. Th., Stefansson, S. O. and Porter, M. 2013. Physiology during smoltification in Atlantic salmon: effect of melatonin implants. Fish Physiol. Biochem., 39, 1079-1088. doi: 10.1007/s10695-012-9765-3

Urke, H.A., Kristensen, T., Arnekleiv, J.V., Haugen, T.O., Kjærstad, G., Stefansson, S.O., Ebbesson, L.O.E. and Nilsen, T.O., 2013. Seawater tolerance and post-smolt migration of wild Atlantic salmon Salmo salar × brown trout S. trutta hybrid smolts, J. Fish Biol., 82, 206–227, doi:10.1111/j.1095-8649.2012.03481.x

National projects (Research Council of Norway)

NFFR V.701.146 'Miljøforholdene i settefisk­produksjon', 1986 - 1988

NTNF HB 23.22395 'Lys i fiskeoppdrett', 1987 - 1989

NFFR V.701.211 'Halvtårssmolt', 1988 - 1990

NFFR V.701.236 'Lys i matfiskprodu­ksjon', 1989 - 1991

NFFR 1401-701.321 'Smoltkvalitet og helse', 1991 - 1993

NFR 108848 ‘Smoltkvalitet, sesonguavhengig utsetting og tidlig sjøvannsfase’, 1995 - 1998

NFR 108098 ‘Postsmoltøkologi – trofisk nivå og vandringer’, 1995 - 1997

NFR 110993 ‘Miljømessig og arvelig regulering av vekst hos ung kveite i oppdrett’, 1996 - 1999

NFR 122845 ‘Det arvelige grunnlaget for smoltifisering hos oppdrettslaks og villaks – en grunnleggende studie’, 1998 - 2000

NFR 133964 ’Vannbehov og vannkvalitet under intensiv smoltproduksjon. Hva er grenseverdiene og hvordan unngå skadelige effekter av lav vanngjennomstrømming, lav pH og høg CO2 under intensiv smoltproduksjon?’, 2000 – 2002

NFR 133937 ‘Control of age at first sexual maturity (puberty) in farmed Atlantic salmon’, 2000 – 2002

NFR 149790 'Distribution and ecology of post-smolt and salmon at sea', 2002 - 2005

NFR 149796 ‘The importance of early marine feeding on the growth and survival of Atlantic salmon post-smolt in Norwegian fjords’, 2002 - 2006

NFR 153230 ‘Environmental control of smolt brain development’, 2003 – 2005

NFR 165331 ‘Environmental impact and molecular regulation of the osmoregulatory gill during parr-smolt transformation in Atlantic salmon’, 2005 – 2007

NFR 163429 ‘Optimisation of harvested halibut by lowering maturation, increasing growth and improving flesh quality’ 2005 – 2007

NFR 165239 ‘Sjøvannsinnblanding i intensiv smoltproduksjon: effekter på helse, velferd og risiko for vintersår’, 2005 – 2007

NFR 172504 ’Nitric oxide regulation of development in fish: emphasis on the light-brain-pituitary axis and gill during salmon smoltification’, 2006 - 2008

NFR 1722630 ‘Progressive, modern production of juvenile Atlantic cod’ (PROCOD), 2006 - 2009

NFR 172514 ‘Moderne settefiskproduksjon av laks - normal utvikling og velferd i intensive oppdrettsystemer’, 2006 - 2009

NFR 184997 ‘Optimal smolt production and post smolt performance in the High North - Seawater intermixing, low temperatures and intensive rearing’ (NORSMOLT), 2008 – 2011

NFR 190469 ‘Fish welfare assessment through brain function: Impacts of environmental stress on brain plasticity and behaviour’, 2009 – 2011

NFR 199800 ‘The smolt probe - novel tools for assessment of smolt quality and marine performance in Atlantic salmon’, 2010 – 2012

NFR 199518 ‘Early puberty in salmon males in seawater - causes and consequences for hypoosmoregulatory ability and welfare’, 2010 – 2013

NFR 199482 ‘Cod Development CODE’, 2010 – 2013

NFR 222215 ’The smolt brain model: Unraveling nature´s regulation of neural plasticity’, 2013 – 2015

NFR 233870 ‘Welfare of Atlantic salmon postsmolts in closed-containment production systems, using a function-based approach’ (SalmoFutura), 2014-2016

NFR 256199 ‘Optimal bruk av rognkjeks til avlusing av oppdrettslaks, LUSINFE’R, 2016 – 2020

NFR 269043 ‘Kontroll av kjønnsmodning hos rognkjeks, STAMINA’, 2017 – 2021

National strategic programs (Research Council of Norway)

114646 ‘Teori- og eksperimentbasert studie av rekruttering hos marin fisk’, 1995 - 1998

136260 ‘Smolting in Atlantic salmon: the interrelationship between physiological, endocrine and immunological changes, and their genetic regulation’, 2000 - 2006

Other national programs (Fiskeri og havbruksnæringens forskningsfond, FHF)

FHF/NFR 155157 'Vannkvalitet – smoltkvalitet', 2003 – 2005

International projects

Nordisk Industri­fond 88.107 'Helårlig produksjon av atlantisk laks ved styrt kjønns­mo­dning og smoltifiser­ing', 1988 - 1991

EU, FAIR-CT96-1410 ‘Environmental and neuroendocrine control mechanisms in finfish reproduction and their application in broodstock management’, 1997 - 1999

EU, FAIR-CT97-3544 ‘A multidisciplinary evaluation and optimization of the production characteristics of different strains of commercially cultured flatfish’, 1998 - 2000

Wallenberg foundation, 1997 - 2001

‘Aquaculture and Fisheries Development: Basic Research on Finfish Reproduction and Growth Enabling the Intensification of Aquaculture’

‘The Multiple Gonadotropin-Releasing Hormones (GnRH) of Fish: Functions and Potential Use for Spawning Manipulations in Commercially and Ecologically Important Fish Species’

EU, QoL, QLRT-2001-01801 ‘Photoperiod control of puberty in farmed fish: Development of new techniques and research into underlying physiological mechanisms’, 2002 - 2005

EU, LSF ‘Marine Pelagic Food Chain Research’, (Contract No ERBFMGECT950013)

Research collaborators/topics:

Professor Niall Bromage, University of Stirling, Skottland

Temperature effects on melatonin in post-smolt Atlantic salmon (Salmo salar), 1997

Professor Sjoerd E. Wendelaar Bonga, Katholieke Universiteit Nijmegen, Nederland

The effect of temperature on growth performance and stress resistance in two generations of turbot (Scophthalmus maximus Rafinesque), 1997

Influence of temperature and feeding ration on the bioenergetics of juvenile turbot (Scophthalmus maximus) and Atlantic halibut (Hippoglossus hippoglossus), 1998

Dr. Richard FitzGerald, University College Cork, Irland

The effect of different initial size distribution on the growth of Atlantic halibut (Hippoglossus hippoglossus L.), 1998

Dr. Ewa Kulczykowska, Marine Biology Center of Polish Academy of Sciences, Gdynia, Polen

Melatonin – Arginine vasotocin relationship during development of Salmo salar, 2001

EU, Improving Human Potential, Access to Research Infrastructure, Institute of Aquaculture, University of Stirling, Scotland, Contract HPRI-CT-1999-00106

Professor Niall Bromage

Endocrine regulation of growth and food intake in salmon smolts, 2000/2001

EU, FP7-KBBE-2007-2A, 222719, LIFECYCLE—Building a biological knowledge-base on fish lifecycles for competitive, sustainable European aquaculture (01.03.2009 – 28.02.2013)


Centre for research based innovation (SFI): Centre for Research-based Innovations in Controlled-environment Aquaculture (CtrlAQUA), 2015 – 2023. http://ctrlaqua.no/



Cand. scient., Dept. of Fisheries Biology, University of Bergen (UiB), 25.06.1986

Thesis: Lysperiodens virkning på vekst og smoltifiser­ing hos laks (Salmo salar L.)

Dr. scient., Dept. of Fisheries and Marine Biology, UiB, 10.12.1990

Thesis: The influence of light on growth and parr-smolt trans­formation of Atlantic salmon (Salmo salar L.): Effects of spectral composition, light intensity and photoperiod