Browsing Brage IMR by Author "Hansen, Tom Johnny"
Now showing items 1-20 of 59
-
Adaptive photoperiod interpretation modulates phenological timing in Atlantic salmon
Oldham, Tina Marie Wier; Oppedal, Frode; Fjelldal, Per Gunnar; Hansen, Tom Johnny (Peer reviewed; Journal article, 2023)Photoperiod, the portion of 24-h cycle during which an organism is exposed to illumination, is an important phenological cue in many animals. However, despite its influence on critical biological processes, there remain ... -
An Industry-Scale Mass Marking Techniquefor Tracing Farmed Fish Escapees
Warren-Myers, Fletcher; Demster, Tim; Fjelldal, Per Gunnar; Hansen, Tom Johnny; Swearer, Stephen E. (Journal article; Peer reviewed, 2015-03-04)Farmed fish escape and enter the environment with subsequent effects on wild populations. Reducing escapes requires the ability to trace individuals back to the point of escape, so that escape causes can be identified and ... -
Anatomical and pathological characteristics of ribs in the Atlantic salmon (Salmo salar L.) and its relevance to soft tissue changes
Brimsholm, Malin Helen; Fjelldal, Per Gunnar; Hansen, Tom Johnny; Trangerud, Cathrine; Knutsen, Geir Magne; Asserson, Charlotte Finstad; Koppang, Erling Olaf; Bjørgen, Håvard (Peer reviewed; Journal article, 2023)Studies on the anatomical and pathological characteristics of ribs in farmed Atlantic salmon (Salmo salar L.) are warranted due to their possible association with red and melanized focal changes (RFC and MFC) in the fillet, ... -
Atlantic salmon male post-smolt maturation can be reduced by using a 3-hour scotophase when inducing smoltification
Fraser, Thomas; Hansen, Tom Johnny; Norberg, Birgitta; Nilsen, Tom Ole; Schulz, Rüdiger W.; Fjelldal, Per Gunnar (Peer reviewed; Journal article, 2023)Photoperiod regulates the occurrence of unwanted male post-smolt maturation during the production of large (>100 g) Atlantic salmon (Salmo salar) smolts. However, the optimal daylength for triggering smoltification, but ... -
Autosomal sdY pseudogenes explain discordances between phenotypic sex and DNA marker for sex identification in Atlantic salmon
Ayllon, Fernando; Solberg, Monica Favnebøe; Besnier, Francois; Fjelldal, Per Gunnar; Hansen, Tom Johnny; Wargelius, Anna; Edvardsen, Rolf Brudvik; Glover, Kevin (Peer reviewed; Journal article, 2020)Despite the key role that sex-determination plays in evolutionary processes, it is still poorly understood in many species. In salmonids, which are among the best studied fishes, the master sex-determining gene sexually ... -
Blue mussel (Mytilus edulis) silage, a possible low trophic marine protein source for Atlantic salmon (Salmo salar L.)
Sartipiyarahmadi, Sahar; Philip, Antony Jesu Prabhu; Forshei, Aksel N.; Sveier, Harald; Steinsund, Silje; Kleppe, Malin; Lock, Erik Jan Robert; Madaro, Angelico; Hansen, Tom Johnny; Strand, Øivind; Wiech, Martin; Jakobsen, Jan Vidar; Remø, Sofie C. (Peer reviewed; Journal article, 2024)Blue mussel (Mytilus edulis) could be a promising marine protein source in fish feeds and is of great interest since it can be cultivated along the Norwegian coastline. However, the use of blue mussels in feeds is dependent ... -
Cardiac responses to elevated seawater temperature in Atlantic salmon
Jørgensen, Sven Martin; Castro, Vicente; Krasnov, Aleksei; Torgersen, Jacob; Timmerhaus, Gerrit; Hevrøy, Ernst Morten; Hansen, Tom Johnny; Susort, Sissel Tjøstheim; Breck, Olav; Takle, Harald Rune (Peer reviewed; Journal article, 2014) -
Changes in water temperature and oxygen: the effect of triploidy on performance and metabolism in large farmed Atlantic salmon
Sambraus, Florian; Remen, Mette; Olsen, Rolf Erik; Hansen, Tom Johnny; Waagbø, Rune; Torgersen, Thomas; Lock, Erik-Jan; Imsland, Albert; Fraser, Thomas W.K.; Fjelldal, Per Gunnar (Peer reviewed; Journal article, 2018) -
Chromosomal aberrations and early mortality in a non-mammalian vertebrate: example from pressure-induced triploid Atlantic salmon
Delaval, Aurelien Nicolas; Glover, Kevin Alan; Solberg, Monica Favnebøe; Fjelldal, Per Gunnar; Hansen, Tom Johnny; Harvey, Alison C. (Peer reviewed; Journal article, 2024)In commercial aquaculture, the production of triploid fish is currently the most practical approach to prevent maturation and farm-to-wild introgression following escapes. However, triploids often exhibit poor welfare, and ... -
Chromosome aberrations in pressure-induced triploid Atlantic salmon
Glover, Kevin; Harvey, Alison C.; Hansen, Tom Johnny; Fjelldal, Per Gunnar; Besnier, Francois; Bos, J.B.; Ayllon, Fernando; Taggart, John B.; Solberg, Monica Favnebøe (Peer reviewed; Journal article, 2020)Triploid organisms have three sets of chromosomes. In Atlantic salmon, hydrostatic pressure treatment of newly fertilized eggs has been extensively used to produce triploids which are functionally sterile due to their ... -
Cloned and outbred Atlantic salmon display equal parasite dispersion when infected with the salmon louse
Glover, Kevin; Hansen, Tom Johnny; Besnier, Francois; Solberg, Monica Favnebøe; Fjelldal, Per Gunnar; Sørvik, Anne Grete Eide; Dalvin, Sussie; Nilsen, Frank (Peer reviewed; Journal article, 2017) -
Comparing physiological responses of acute and chronically stressed diploid and triploid Atlantic salmon (Salmo salar)
Madaro, Angelico; Lai, Floriana; Fjelldal, Per Gunnar; Hansen, Tom Johnny; Gelebart, Virginie; Muren, Brynjar; Rønnestad, Ivar; Olsen, Rolf-Erik; Stien, Lars Helge (Peer reviewed; Journal article, 2024)We compared the performance and physiological response of diploid and triploid Atlantic salmon (Salmo salar) following 21 days of either unpredictable chronic stress (UCS) or no disturbance (control). Thereafter, all four ... -
A comparison of triploid and diploid Atlantic salmon (Salmo salar) performance and welfare under commercial farming conditions in Norway
Madaro, Angelico; Kjøglum, Sissel; Hansen, Tom Johnny; Fjelldal, Per Gunnar; Stien, Lars Helge (Peer reviewed; Journal article, 2021)Avoiding genetic interactions between wild and farmed Atlantic salmon is regarded as one of the major requirements for a sustainable salmon aquaculture industry. For this reason, farming functional sterile triploids has ... -
Development of supermale and all-male Atlantic salmon to research the vgll3 allele - puberty link
Fjelldal, Per Gunnar; Hansen, Tom Johnny; Wargelius, Anna; Ayllon, Fernando; Glover, Kevin Alan; Schulz, Rüdiger W.; Fraser, Thomas (Peer reviewed; Journal article, 2020)Farmed Atlantic salmon are one of the most economically significant global aquaculture products. Early sexual maturation of farmed males represents a significant challenge to this industry and has been linked with the vgll3 ... -
The Distribution of IgT mRNA+ Cells in the Gut of the Atlantic Salmon (Salmo salar L.)
Castro, Pedro Luis; Barac, Fran; Hansen, Tom Johnny; Fjelldal, Per Gunnar; Hordvik, Ivar; Bjørgen, Håvard; Koppang, Erling Olaf (Peer reviewed; Journal article, 2023)The newly discovered IgT+ B cell is thought to play a dominant role in mucosal immunity, but limited studies have examined its distribution in fish species, hindering our understanding of its function. This study investigated ... -
Effects of laboratory salmon louse infection on mortality, growth, and sexual maturation in Atlantic salmon
Fjelldal, Per Gunnar; Fraser, Thomas; Hansen, Tom Johnny; Karlsen, Ørjan; Bui, Samantha (Peer reviewed; Journal article, 2022)Elevated salmon louse infection pressure generated by salmon farming represents a major threat for wild Atlantic salmon (Salmo salar). This study explored the effect of salmon lice on mortality, and body and gonad growth ... -
Effects of laboratory salmon louse infection on osmoregulation, growth and survival in Atlantic salmon
Fjelldal, Per Gunnar; Hansen, Tom Johnny; Karlsen, Ørjan (Peer reviewed; Journal article, 2020)Anadromous Atlantic salmon (Salmo salar) rely on long ocean migrations to build energy stores for maturation and spawning. In seawater, wild Atlantic salmon are threatened by high salmon lice (Lepeophtheirus salmonis) ... -
Effects of light source and intensity on sexual maturation, growth and swimming behaviour of Atlantic salmon in sea cages
Hansen, Tom Johnny; Fjelldal, Per Gunnar; Folkedal, Ole; Vågseth, Tone; Oppedal, Frode (Peer reviewed; Journal article, 2017) -
Effects of photoperiod and melatonin implants on feed intake in Atlantic salmon (Salmo salar L.) postsmolts
Maiolo, Silvia; Hansen, Tom Johnny; Parisi, Giuliana; Olsen, Rolf Erik (Journal article; Peer reviewed, 2015-09-15)High melatonin concentrations were expected to negatively affect Atlantic salmon appetite. Hence, individually kept Atlantic salmon postsmolts were subjected to continuous light (24:0, L:L) or natural daylight (12:12, L:D) ... -
Effects of temperature and feeding regime on cortisol concentrations in scales of Atlantic salmon post-smolts
O'Toole, Christina; White, Philip; Thomas, Katie; O'Maoiléidigh, Niall; Fjelldal, Per Gunnar; Hansen, Tom Johnny; Graham, Conor T.; Brophy, Deirdre (Peer reviewed; Journal article, 2023)Anadromous fish are vulnerable to anthropogenic and environmental stressors including pollution, rising temperatures, and changes in food availability. Knowledge of how fish respond to specific stressors aid our understanding ...