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Ragnar Nortvedt

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Researcher
Telephone: 92829508
Department: Fôr og ernæring

Curriculum Vitae

I have many years experience as researcher (Master in 1987, PhD in 1997) and as 1183 researcher (since year 2000) and professor within fish feed formulation, nutrition, fish welfare and slaughter quality from IMR, NIFES and University of Bergen (1987 - 2008). In 2008 - 2012 I held two positions as Quality Manager and Director having responsabilities for product quality and food safety in the aquaculture industry and I managed a research consortium in medical image analysis and visualization (2012 - 2017) at Haukeland University Hospital. I was head of Matre Research Station (1211 Section manager) in the period 2017 - 2024. From April 2024 I returned to my previous position as senior research scientist in the Feed & Nutrition research group in Bergen. Lately I have become more focused on applications and ethical considerations on the applications of artificial intelligence. High mobility by working two periods at Matre, one period in Austevoll and two periods in Bergen is one of my key qualifications. I have also contributed as Manager of IK Akva at IMR for seven years and been member of the Miljøfyrtårn group for three years. Moreover, International tasks: I have managed two international committees through NOKUT to evaluate 1) The Master program and 2) The PhD program at the University College in Bodø before they became Nord University. I have been western coordinator of the 1st International Chemometric Conference in Zhangiage in China (1996), had six months sabattical at Pacific Biological Statiion in Nanaimo, Canada (2001) and worked as technical advisor for NORAD at University of Fisheries in NhaTrang, Vietnam (2004 - 2008).  I have had a one year 20 % adjunct position as program coordinator in NRC (1998) and as 20 % researcher at Nofima Ingredients in Kjerreidviken (2008).

Publications

Academic articles

2017

Prolonged intestinal transit and diarrhea in patients with an activating GUCY2C mutation

Hilde Løland Von Volkmann, Ingeborg Brønstad, Odd Helge Gilja, Rune Rose Tronstad, Dag André Sangnes, Ragnar Nortvedt, Trygve Hausken, Georg Gjorgji Dimcevski, Torunn Fiskerstrand, Kim Nylund
PLOS ONE 12
2016

Optimal AC frequency range for electro-stunning of Atlantic salmon (Salmo salar)

Endre Grimsbø, Ragnar Nortvedt, Bjørn Tore Hjertaker, Erling Hammer, Bjørn Roth
Aquaculture 451 p. 283-288
2014

Preventing injuries and recovery for electrically stunned Atlantic salmon (Salmo salar) using high frequency spectrum combined with a thermal shock

Endre Grimsbø, Ragnar Nortvedt, Erling Hammer, Bjørn Roth
Aquaculture 434 p. 277-281
2014

The effect of stunning methods and season on muscle texture hardness in Atlantic salmon (Salmo salar L.)

Grigory Merkin, Lars Helge Stien, Karin Pittman, Ragnar Nortvedt
Journal of Food Science 79 p. E1137-E1141
2013

Comparison of fillet composition and initial estimation of shelf life of cobia (Rachycentron canadum) fed raw fish or fish silage moist diets

Diep Mach Ellertsen, Ragnar Nortvedt
Aquaculture Nutrition 19 p. 333-342
2013

Digital image analysis as a tool to quantify gaping and morphology in smoked salmon slices

Grigory Merkin, Lars Helge Stien, Karin Pittman, Ragnar Nortvedt
Aquacultural Engineering 54 p. 64-71
2012

Live chilling of Atlantic salmon: physiological response to handling and temperature decrease on welfare

A. Foss, Endre Grimsbø, E Vikingstad, Ragnar Nortvedt, Erik Slinde, Bjørn Roth
38 p. 565-571
2012

Crowding, pumping and stunning of Atlantic salmon, the subsequent effect on pH and rigor mortis

Bjørn Roth, Endre Grimsbø, Erik Slinde, Atle Foss, Lars Helge Stien, Ragnar Nortvedt
Aquaculture 326-329 p. 178-180
2011

Free amino acid distribution in plasma and liver of juvenile cobia (Rachycentron canadum) fed increased levels of lizardfish silage

Diep Thi Ngoc Mach, Ragnar Nortvedt
Aquaculture Nutrition 17 p. E644-E656
2010

Effect of pre-slaughter procedures on stress responses and some quality parameters in sea-farmed rainbow trout (Oncorhynchus mykiss)

Grigory Merkin, Bjørn Roth, Camilla Gjerstad, Erik Dahl-Paulsen, Ragnar Nortvedt
Aquaculture 309 p. 231-235
2010

Electrical stimulation of Atlantic salmon muscle and the effect on flesh quality

Bjørn Roth, Ragnar Nortvedt, Erik Slinde, Atle Foss, Endre Grimsbø, Lars Helge Stien
Aquaculture 301 p. 85-90
2010

Percussion and electrical stunning of Atlantic salmon (Salmo salar) after dewatering and subsequent effect on brain and heart activities

Bert Lambooij, Endre Grimsbø, Hans van de Vis, Henny G.M. Reimert, Ragnar Nortvedt, Bjørn Roth
Aquaculture 300 p. 107-112
2010

Effects on digestibility and growth of juvenile cobia (Rachycentron canadum) fed fish or crab silage protein

Diep Thi Ngoc Mach, Mao Dinh Nguyen, Ragnar Nortvedt
Aquaculture Nutrition 16 p. 305-312
2009

Laksebein i fôr til torsk. - Biologisk evaluering av laksebeinmel som alternativ proteinkilde i torskefôr

Sissel Albrektsen, Åshild Krogdahl, Ragnar Nortvedt, Kjartan Sandnes, Marie Hillestad
Rubin 178
2009

Chemical and nutritional quality of silage made from raw or cooked lizard fish (Saurida undosquamis) and blue crab (Portunus pelagicus)

Diep Thi Ngoc Mach, Ragnar Nortvedt
Journal of the Science of Food and Agriculture 89 p. 2519-2526
2009

A consumer preference study of raw Norwegian rainbow trout (Oncorhynchus mykiss) as sashimi with focus on young adults in Japan

Izumi Sone, Ragnar Nortvedt
44 p. 2055-2061
2009

Factors affecting residual blood and subsequent effect on bloodspotting in smoked Atlantic salmon fillets

Bjørn Roth, Alex Obach, Dougie Hunter, Ragnar Nortvedt, Fernando Oyarzun
Aquaculture 297 p. 163-168
2007

Optimization of activated carbon-based decontamination of fish oil by response surface methodology

Åge Oterhals, Marianne Solvang, Ragnar Nortvedt, MARC BERNTSSEN
European Journal of Lipid Science and Technology 109 p. 691-705
2007

Exsanguination of turbot and the effect on fillet quality measured mechanically, by sensory evaluation, and with computer vision

Bjørn Roth, R. Schelvis, Lars Helge Stien, Atle Foss, Ragnar Nortvedt, Albert Imsland
Journal of Food Science 72 p. E525-E531
2006

Quality characterization of farmed Atlantic halibut during ice storage

Christelle Guillerm-Regost, Trine Haugen, Nortvedt Ragnar, Mats Carlehög, Bjørn-Tore Lunestad, Anders Kiessling, Anna Maria Bencze Rørå
Journal of Food Science 71 p. 83-90
2006

Seasonal variations in muscle growth dynamics and selected quality attributes in Atlantic halibut (Hippoglossus hippoglossus L.) fed dietary lipids containing soybean and/or herring oil under different rearing regimes

Trine Haugen, Anders Kiessling, Rolf Erik Olsen, Mia Rørå Bencze, Erik Slinde, Nortvedt Ragnar
Aquaculture 261 p. 565-579
2006

Compensatory growth and fillet crude composition in juvenile Atlantic halibut: Effects of short term starvation periods and subsequent feeding

Andreas Heide, Atle Foss, Sigurd Stefansson, Ian Mayer, Birgitta Norberg, Bjørn Roth, Mads D. Jenssen, Ragnar Nortvedt, Albert Imsland
Aquaculture 261 p. 109-117
2006

Nutritional composition of blubber and meat of hooded seal (Cystophora cristata) and harp seal (Phagophilus groenlandicus) from Greenland

Linn Anne Bjelland Brunborg, Kåre Julshamn, Ragnar Nortvedt, Livar Frøyland
Food Chemistry 96 p. 524-531
2006

Quality characterization of farmed Atlantic halibut during ice storage

C. Guillerm-Regost, T. Haugen, Ragnar Nortvedt, M. Carlehög, B.T. Lunestad, A. Kiessling, A.M.B. Rørå
Journal of Food Science 71 p. S83-S90
2006

Seasonal variations in muscle growth dynamics and selected quality attributes in Atlantic halibut (Hippoglossus hippoglossus L.) fed dietary lipids containing soybean and/or herring oil under different rearing regimes

T. Haugen, A Kiessling, R.E. Olsen, Anna Maria Bencze Rørå, E. Slinde, Ragnar Nortvedt
Aquaculture 261 p. 565-579
2005

The effects of stress and storage temperature on the colour and texture of pre-rigor filleted farmed cod (Gadus morhua L.)

Lars Helge Stien, Elisabeth Hirmas, Marit Bjørnevik, Ørjan Karlsen, Ragnar Nortvedt, Anna Maria Bencze Rørå, Jan Sunde, Anders Kiessling
Aquaculture Research 36 p. 1197-1206
2004

Interactions between ice storage time, collagen composition, gaping and textural properties in farmed salmon muscle harvested at different times of the year

Marit Espe, Kari Ruohonen, Marit Bjørnevik, Livar Frøyland, Nortvedt Ragnar, Anders Kiessling
Aquaculture 240 p. 489-504
1991

Multivariate approach to the study of fish growth

Ragnar Nortvedt, Tom Johnny Hansen, Frode Brakstad, Trygve Lunde, Steinar Skybakmoen
Chemometrics and Intelligent Laboratory Systems 14 p. 279-286
1990

First feeding of Atlantic salmon, Salmo salar L., under different photoperiods and light intensities

Sigurd Olav Stefansson, Ragnar Nortvedt, Tom Johnny Hansen, Geir Lasse Taranger
Aquaculture and Fisheries Management 21 p. 435-441
1986

The effect of a short time exposure to different temperature and salinity regimes on survival of maturing Atlantic salmon and eyed eggs, and changes in blood and seminal plasma during the spawning period

Sissel Albrektsen, Ragnar Nortvedt, Ole Torrissen
ICES Journal of Marine Science F:25

Scientific lectures

2007

Produktutvikling fra silderogn

Nortvedt, Ragnar
2006

Seasonal growth, muscle fibre size distribution and quality characterization of farmed atlantic halibut Hippoglossus hippoglossus fed soybean oil and/or marine lipids for 1 year

Trine Haugen, Mats Carlehog, Anders Kiessling, Bjørn-Tore Lunestad, Nortvedt Ragnar, Christelle Regost, Mia Rora, Erik Slinde
2004

Anvendelse av bildeanalyse og andre ikke-destruktive målemetoder for kvalitetsvurdering av fisk

Lars H. Stien, Fredrik Manne, Anders Kiessling, Jorma Suontama, Nortvedt Ragnar
2001

Interaction between raw material characteristics and smoking process on quality of smoked salmon

Ragnar Nortvedt, Hannes Hafsteinsson, J.L. Vallet, J Borderias, Ole Torrisen, Øyvind Lie, Magny Skinlo Thomassen, Sjøfn Sigurgisladottir, M Cardinall, Marit Bjørnevik, P Garcia, Marit Espe

Poster

2011

ELECTRO STUNNING OF ATLANTIC SALMON (Salmo salar L.): FACTORS THAT AFFECT THE STUNNING CURRENT

Endre Grimsbø, Bjørn Roth, Ragnar Nortvedt
2009

LIVE CHILLING OF ATLANTIC SALMON: EFFECTS FROM HANDLING AND TEMPERATURE DECREASE ON WELFARE

Atle Foss, Endre Grimsbø, E Vikingstad, Ragnar Nortvedt, Erik Slinde, B. Roth

Reports and dissertations

2016

Measuring methods for fish welfare during slaughter based on electrical impedance, EEG, ECG and blood parameters

Endre Grimsbø, Ragnar Nortvedt
2016

Measuring methods for fish welfare during slaughter based on electrical impedance, EEG, ECG and blood

Endre Grimsbø, Ragnar Nortvedt
2007

The opportunities in the catfish surplus market in Vietnam

Nortvedt, Ragnar
2007

Effects of synthetic antioxidants and light exporsure on fish oil oxidation and effects of graded levels of CoQ10 in fish feed on accumulation in fillet and liver of Atlantic salmon (Salmo salar L.)

Veronika Tkachenko, Ragnar Nortvedt
2007

Injection of pre rigor fillets from Atlantic salmon (Salmo salar) and Atlantic cod (Gadus morhua) with salt solutions of Na+, Ca2+, and distilled water. The effect on rigor morits, texture, colour, and weight changes

Ana Maria Gutiérrez, Ragnar Nortvedt
2006

Tilsetning og forekomst av Listeria monocytogenes i rakfisk under systematisk variasjon i salt, sukker, nisin, melkesyrebakterier og variabel lagringstemperatur, samt effekter på sensorisk kvalitet

Kathrine Marie Løkling Lunde, Ragnar Nortvedt
2006

Anbefalinger av kjemiske kvalitetsmetoder og prøvetakingsstørrelse på islagret oppdrettet og vill atlantisk torsk (Gadus morhua)

Siri Smith-Giske, Ragnar Nortvedt
2006

Occurrence and distribution of parasitic Anisakis sp. larvae (Nematoda, Anisakidae) in the body musculature of Atlantic mackerel (Scomber scombrus) and Norwegian spring spawning herring (Clupea harengus)

Hiswaty Hafid, Ragnar Nortvedt
2006

Anvendelse av Nær Infrarød Spektroskopi og kvalitetsindeksmetoden for å bestemme holdbarhet i torsk (Gadus morhua)

Linn Eide, Ragnar Nortvedt
2006

Effects of graded levels of vitamin C and vitamin E on the oxidation status and color appearance of cool stored fillets and liver of Atlantic cod (Gadus morhua)

Thao La Xuan, Ragnar Nortvedt
2006

Effekt av ulike bedøvelses- og slaktetemperaturregimer på korttidsstress og kvalitet hos oppdrettstorsk (Gadus morhua), vurdert ved kvalitetsindeksmetoden (QIM)

Halldis Olsen, Ragnar Nortvedt
2006

Muscle growth dynamics and quality of Atlantic halibut (Hippoglossus hippoglossus L.)

Trine Haugen, Ragnar Nortvedt
2006

Application of machine vision to quantify rigor development, colour and fat content in slaughtered fish

Lars Helge Stien, Ragnar Nortvedt
2006

ATP degradation, fillet contraction and sensory evaluation of farmed Atlantic cod (Gadus morhua) subjected to a handling stress situation and starvation

Amir Ebrahim Yazdanpanah Amin, Ragnar Nortvedt
2004

The fatty acid contents in the muscle and liver of wild, fed-wild and farmed cod (Gadus morhua), and its development of rancidity during storage in ice or in slurry

Thi Ngoc Diep Mach, Ragnar Nortvedt
2004

A comparison of the quality deterioration in the Atlantic cod (Gadus morhua) and the Nile perch (Lates niloticus) stored in ice or slurry

John Bosco Ahimbisibwe, Ragnar Nortvedt
1997

A multivariate approach to the study of growth, feed utilization, body composition and sensory assessment of cultured Atlantic halibut (Hippoglossu hippoglossus, L., 1758)

Nortvedt, Ragnar
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