Browsing Bergen Open Research Archive by Author "Imsland, Albert"
Now showing items 1-20 of 20
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Caligus elongatus and other sea lice of the genus Caligus as parasites of farmed salmonids: A review
Hemmingsen, Willy; MacKenzie, Ken; Sagerup, Kjetil; Remen, Mette; Bloch-Hansen, Karin; Imsland, Albert (Journal article; Peer reviewed, 2020)This review was prompted by reports of unusually large numbers of sea lice tentatively identified as Caligus elongatus infesting farmed salmon in northern Norway. Following a brief introduction to the sea lice problem in ... -
Catch me if you can: How to recapture lumpfish using light as an attractant
Foss, Atle; Imsland, Albert; Roth, Bjørn; Nytrø, Ane Vigdisdatter (Journal article; Peer reviewed, 2020)The use of lumpfish in salmon farming allows the removal of sea lice all year round, without the use of chemicals or mechanical treatments. In Norway alone, around 31 million lumpfish are currently put into sea pens whereas ... -
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)In salmon farming, the use of sterile triploids (3N) can mitigate the problem of escapees interbreeding with wild salmon. However, triploid salmon appear less tolerant to high water temperatures and low oxygen levels ... -
Comparison of diet composition, feeding, growth and health of lumpfish (Cyclopterus lumpus L.) fed either feed blocks or pelleted commercial feed
Imsland, Albert; Reynolds, Patrick; Jonassen, Thor Magne; Hangstad, Thor Arne; Adron, John; Elvegård, Tor Anders; Urskog, Tonje Cecilie; Hanssen, Anna; Mikalsen, Bjørn (Peer reviewed; Journal article, 2019)Two duplicate groups of individually tagged lumpfish (mean initial weight: 21.5 ± 3.2 g) were fed either a commercially available lumpfish feed or feed blocks for a period of 123 days. The aim was to evaluate and compare ... -
Comparison of diet composition, feeding, growth and health of lumpfish (Cyclopterus lumpus L.) fed either feed blocks or pelleted commercial feed
Imsland, Albert; Reynolds, Patrick; Jonassen, Thor Magne; Hangstad, Thor Arne; Adron, John; Elvegård, Tor Anders; Urskog, Tonje Cecilie; Hanssen, Anna; Mikalsen, Bjørn (Peer reviewed; Journal article, 2019)Two duplicate groups of individually tagged lumpfish (mean initial weight: 21.5 ± 3.2 g) were fed either a commercially available lumpfish feed or feed blocks for a period of 123 days. The aim was to evaluate and compare ... -
Consumption of sea lice by lumpfish (Cyclopterus lumpus): qPCR quantification and use of a non-destructive sampling method
Imsland, Albert; Micallef, Giulia; Korsnes, Kjetil; Reynolds, Patrick (Peer reviewed; Journal article, 2019)In the present study, it was attempted to quantify sea lice grazing in lumpfish by using a recently published qPCR assay. This method utilizes a small aliquot (10 μL) of the stomach fluid of the lumpfish which can be ... -
The effect of continuous light at low temperatures on growth in Atlantic salmon reared in commercial size sea pens
Imsland, Albert; Roth, Bjørn; Fjelldal, Per Gunnar; Stefansson, Sigurd Olav; Handeland, Sigurd Olav; Mikalsen, Bjørn (Peer reviewed; Journal article, 2017-10)The aim of this study was to investigate the effect of continuous light of different duration, applied from late autumn to spring in the second year of the production cycle, on the production performance of Atlantic salmon ... -
Effects of altered photoperiod regimes during winter on growth and gonadosomatic index in Arctic charr (Salvelinus alpinus) reared in freshwater
Foss, Atle; Siikavuopio, Sten Ivar; Imsland, Albert (Peer reviewed; Journal article, 2020)The short- and long-term effects of altered photoperiods during winter on growth and final gonadosomatic index (GSI) were investigated in 178 individually tagged 2-year-old smolt Arctic charr from an anadromous strain. The ... -
Effects of different feeding frequencies on growth, cataract development and histopathology of lumpfish (Cyclopterus lumpus L.)
Imsland, Albert; Reynolds, Patrick; Jonassen, Thor Magne; Hangstad, Thor Arne; Elvegård, Tor Anders; Urskog, Tonje Cecilie; Hanssen, Anna; Mikalsen, Bjørn (Peer reviewed; Journal article, 2019)Three duplicate groups of individually tagged lumpfish (mean initial weight: 22.3 ± 2.5 g) were fed either daily (7DW); four days per week (4DW) or three days per week (3DW) at a feeding rate of 2% body weight day−1 for a ... -
Flesh quality of Atlantic salmon smolts reared at different temperatures and photoperiods
Imsland, Albert; Roth, Bjørn; Døskeland, Inge; Fjelldal, Per Gunnar; Stefansson, Sigurd Olav; Handeland, Sigurd O; Mikalsen, Bjørn (Peer reviewed; Journal article, 2019)Possible interactive effects of temperature and photoperiod on flesh quality in Atlantic salmon post‐smolts were studied. Juvenile (initial mean weight 96.0 g ± 3.1 SEM ) Atlantic salmon were reared at six different ... -
Genome- and transcriptomederived microsatellite loci in lumpfsh Cyclopterus lumpus: molecular tools for aquaculture, conservation and fsheries management
Maduna, Simo; Vivian-Smith, Adam; Jónsdóttir, Ólöf Dóra Bartels; Imsland, Albert; Klutsch, Cornelya; Nyman, Tommi; Eiken, Hans Geir; Hagen, Snorre (Journal article; Peer reviewed, 2020)The lumpfish Cyclopterus lumpus is commercially exploited in numerous areas of its range in the North Atlantic Ocean, and is important in salmonid aquaculture as a biological agent for controlling sea lice. Despite the ... -
Impact of environmental factors on the growth and maturation of farmed Arctic charr
Imsland, Albert; Gunnarsson, Snorri; Thorarensen, Helgi (Journal article; Peer reviewed, 2020)Farming of Arctic charr mainly takes place in land‐based farms applying intensive rearing methods with relatively high production costs. Depending on local conditions at each site, it is possible to regulate important ... -
Is habituation measurable in lumpfish cyclopterus lumpus when used as cleaner fish in Atlantic salmon Salmo salar aquaculture?
Staven, Fredrik Ribsskog; Nordeide, Jarle Tryti; Imsland, Albert; Andersen, Per; Iversen, Nina Skorstad; Kristensen, Torstein (Peer reviewed; Journal article, 2019)To investigate how lumpfish interact in Atlantic salmon aquaculture, physiological stress responses and changes in behaviour were analysed in experienced and naive lumpfish. Experienced lumpfish (30.2 ± 7.93 g, mean ± SD) ... -
Metabolic rates, swimming capabilities, thermal niche and stress response of the lumpfish, cyclopterus lumpus
Hvas, Malthe; Folkedal, Ole; Imsland, Albert; Oppedal, Frode (Peer reviewed; Journal article, 2018-09-03)The lumpfish (Cyclopterus lumpus) is a semi-pelagic globiform teleost native to the North Atlantic with a ventral suction disc that allows for attachment onto surfaces. Some local populations are in decline and the species ... -
Modelling sea lice control by lumpfish on Atlantic salmon farms: Interactions with mate limitation, temperature and treatment rules
McEwan, Gregor F.; Groner, Maya L.; Cohen, Allegra A.B.; Imsland, Albert; Revie, Crawford W. (Journal article; Peer reviewed, 2019)Atlantic salmon farming is one of the largest aquaculture sectors in the world. A major impact on farm economics, fish welfare and, potentially, nearby wild salmonid populations, is the sea louse ectoparasite Lepeophtheirus ... -
Physiological response of temperature shocks in turbot and sole
Foss, Atle; Imsland, Albert; van de Vis, Hans; Abbink, Wout; Lambooij, Bert; Roth, Bjørn (Peer reviewed; Journal article, 2019)In the present study, selected temperature drops were examined to investigate the effects of live chilling on stress and welfare in turbot and sole. This study demonstrated that rapid temperature drops from 11°C–12°C and ... -
Possible use of lumpfish to control Caligus elongatus infestation on farmed Atlantic salmon: A mini review
Imsland, Albert; Remen, Mette; Bloch-hansen, karin; Sagerup, Kjetil; Mathisen, Remi; Myklebust, Elisabeth A.; Reynolds, Patrick (Journal article; Peer reviewed, 2020)In this mini review, we systematized current knowledge about the number of Caligus elongatus on farmed Atlantic salmon in relation to the use of lumpfish as cleaner fish. The review was prompted by reports of an unusually ... -
Production performance of Atlantic salmon post-smolts in cyclic hypoxia, and following compensatory growth
Remen, Mette; Aas, Turis Synnøve; Vågseth, Tone; Torgersen, Thomas; Olsen, Rolf Erik; Imsland, Albert; Oppedal, Frode (Peer reviewed; Journal article, 2014-07)This study investigated the production performance of the Atlantic salmon postsmolt (Salmo salar L.) subjected to cyclic oxygen reductions (hypoxia) of varying severity. Triplicate groups (N = 955) were kept at constant ... -
Stocking density and its influence on the productivity of red cusk eel, Genypterus chilensis (Guichenot, 1848), in shallow raceways
Foss, Atle; Imsland, Albert; Briceño, Felipe A.; Magnolfi, Spartaco; Magnolfi, Piero; Gutiérrez, Xavier (Journal article; Peer reviewed, 2020)We compared the growth properties of red cusk eel Genypterus chilensis with initial mean weight ± standard error, 106.2 ± 6.1 g reared in shallow raceways at three different stocking densities (28.5, 46.1, and 60.7 kg m-3) ... -
The use of photoperiods to provide year round spawning in lumpfish Cyclopterus lumpus
Imsland, Albert; Hangstad, Thor Arne; Jonassen, Thor Magne; Stefansson, Sigurd Olav; Nilsen, Tom Ole; Hovgaard, Peter; Elvegård, Tor Anders; Lindberg, Ken Ståle; Mikalsen, Bjørn; Urskog, Tonje Cecilie; Norberg, Birgitta; Andersson, Eva; Spetland, Frank; Reynolds, Patrick (Peer reviewed; Journal article, 2019)In order to provide year round spawning broodstock, lumpfish (initial size 746 g and 24.9 cm) were reared under four different photoperiod regimes from January 2017 to July 2018. One group was reared under simulated natural ...