Browsing Brage IMR by Author "Dempster, Tim"
Now showing items 1-20 of 31
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A metapopulation model reveals connectivity-driven hotspots in treatment resistance evolution in a marine parasite
Coates, Andrew; Robinson, Nicholas Andrew; Dempster, Tim; Samsing, Francisca; Johnsen, Ingrid Askeland; Phillips, Ben L. (Peer reviewed; Journal article, 2022)In salmon aquaculture, the sustainable management of salmon lice (Lepeophtheirus salmonis) is limited by the adaptive capacity of the parasite. This is evident in the repeated evolution of pesticide resistance in the salmon ... -
An industry-scale mass marking technique for tracing farmed fish escapees
Warren-Myers, Fletcher; Dempster, Tim; Fjelldal, Per Gunnar; Hansen, Tom; 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 ... -
Applying genetic technologies to combat infectious diseases in aquaculture
Robinson, Nicholas Andrew; Robledo, Diego; Sveen, Lene; Daniels, Rose Ruiz; Krasnov, Aleksei; Coates, Andrew; Jin, Ye Hwa; Barrett, Luke T.; Lillehammer, Marie; Kettunen, Anne Helena; Phillips, Ben L.; Dempster, Tim; Doeschl-Wilson, Andrea; Samsing, Francisca; Difford, Gareth Frank; Salisbury, Sarah; Gjerde, Bjarne; Haugen, John-Erik; Burgerhout, Erik; Dagnachew, Binyam Sime; Kurian, Dominic; Fast, Mark D.; Rye, Morten; Salazar, Marcela; Bron, James E.; Monaghan, Sean J.; Jacq, Celeste; Birkett, Mike; Browman, Howard I.; Skiftesvik, Anne Berit; Fields, David M.; Selander, Erik; Bui, Samantha; Sonesson, Anna Kristina; Skugor, Stanko; Østbye, Tone-Kari K; Houston, Ross D. (Peer reviewed; Journal article, 2022)Disease and parasitism cause major welfare, environmental and economic concerns for global aquaculture. In this review, we examine the status and potential of technologies that exploit genetic variation in host resistance ... -
Aquaculture-derived trophic subsidy boosts populations of an ecosystem engineer
White, Camille; Bannister, Raymond; Dworjanyn, Simon; Husa, Vivian; Nichols, Peter D.; Dempster, Tim (Journal article; Peer reviewed, 2018)Environmental management of coastal aquaculture is focused on acute impacts of organic and nitrogenous wastes close to farms. However, the energy-rich trophic subsidy that aquaculture provides may create cascades with ... -
Coastal salmon farms attract large and persistent aggregations of wild fish: an ecosystem effect
Dempster, Tim; Uglem, Ingebrigt; Sanchez-Jerez, P.; Fernandez-Jover, D.; Bayle-Sempere, J. T.; Nilsen, Rune; Bjørn, Pål Arne (Journal article; Peer reviewed, 2009-06-18)Coastal aquaculture is a globally expanding enterprise. Currently, 1200 salmon farms operate in coastal Norway, yet their capacity to aggregate and subsequently modify wild fish distributions is poorly known. Aggregations ... -
Cyclic hypoxia exposure accelerates the progression of amoebic gill disease
Oldham, Tina Marie Wier; Dempster, Tim; Crosbie, Phil; Adams, Mark; Nowak, Barbara (Peer reviewed; Journal article, 2020)Amoebic gill disease (AGD), caused by the amoeba Neoparamoeba perurans, has led to considerable economic losses in every major Atlantic salmon producing country, and is increasing in frequency. The most serious infections ... -
Detecting and tracing farmed salmon with natural geo-element otolith ‘fingerprint’ tags: developing and validating tag delivery techniques
Hansen, Tom; Fjelldal, Per-Gunnar; Myers, Fletcher Warren; Swearer, Steve; Dempster, Tim (Rapport fra Havforskningen;11-2015, Research report, 2015-04)Farmed fish escape and enter the environment with possible effects on wild populations. Attempts to reduce the incidence of escape could be assisted if individuals can be traced back to the point of escape, so that escape ... -
Efficacy of salmon lice prevention via snorkel technology depends upon salinity at the farm site, with minimal effects on salmon production and welfare
Oppedal, Frode; Bui, Samantha; Overton, Kathy; Stien, Lars Helge; Dempster, Tim (Journal article; Peer reviewed, 2019)Sea lice are a critical health issue in most salmonid farming regions. New cage-based technologies can prevent infestations from occurring, such as the ‘snorkel’, which introduces an impermeable barrier that separates ... -
Environmental drivers of Atlantic salmon behaviour in sea-cages: a review
Oppedal, Frode; Dempster, Tim; Stien, Lars Helge (Journal article; Peer reviewed, 2011-02-03)Salmon may sense and respond to a range of environmental variables within sea-cages, including light, temperature, salinity, dissolved oxygen, water currents and certain chemical treatments used during production. Environments ... -
Environmental drivers of Atlantic salmon behaviour in sea-cages: a review
Oppedal, Frode; Dempster, Tim; Stien, Lars Helge (Journal article; Peer reviewed, 2011-02-03)Salmon may sense and respond to a range of environmental variables within sea-cages, including light, temperature, salinity, dissolved oxygen, water currents and certain chemical treatments used during production. Environments ... -
Evolutionary predictions for a parasite metapopulation: Modelling salmon louse resistance to pest controls in aquaculture
Coates, Andrew; Robinson, Nicholas Andrew; Dempster, Tim; Johnsen, Ingrid Askeland; Phillips, Ben L. (Peer reviewed; Journal article, 2023)Pests often evolve resistance to pest controls used in agriculture and aquaculture. The rate of pest adaptation is influenced by the type of control, the selective pressure it imposes, and the gene flow between farms. By ... -
Extent and ecological importance of escape through spawning in sea-cages for Atlantic cod
Uglem, Ingebrigt; Knutsen, Øyvind; Kjesbu, Olav Sigurd; Hansen, Øyvind J.; Mork, Jarle; Bjørn, Pål Arne; Varne, Rebekka; Nilsen, Rune; Ellingsen, Ingrid; Dempster, Tim (Journal article; Peer reviewed, 2012-11-14)The culture of certain fish species to sizes at which they can reproduce has led to the escape of fertilised eggs or ‘escape through spawning’. To investigate the extent and ecological importance of spawning in sea-cages ... -
Farmed salmonids drive the abundance, ecology and evolution of parasitic salmon lice in Norway
Dempster, Tim; Overton, Kathy; Bui, Samantha; Stien, Lars Helge; Oppedal, Frode; Karlsen, Ørjan; Coates, Andrew; Phillips, B. L.; Barrett, Luke T. (Peer reviewed; Journal article, 2021)Sea cage fish farming is typically open to the environment, with disease transmission possible between farmed and wild hosts. In salmonid aquaculture, salmon louse Lepeophtheirus salmonis infestations cause production ... -
Fluctuating sea-cage environments modify the effects of stocking densities on production and welfare parameters of Atlantic salmon (Salmo salar L.)
Oppedal, Frode; Vågseth, Tone; Dempster, Tim; Juell, Jon-Erik; Johansson, David (Journal article; Peer reviewed, 2011-05-21)Stocking densities are commonly used to set limits for the production of fish in sea-cages, yet limited information exists to assess how environmental fluctuations modify the effects of stocking densities on the production ... -
Fluctuating sea-cage environments modify the effects of stocking densities on production and welfare parameters of Atlantic salmon (Salmo salar L.)
Oppedal, Frode; Vågseth, Tone; Dempster, Tim; Juell, Jon-Erik; Johansson, David (Journal article; Peer reviewed, 2011-05-21)Stocking densities are commonly used to set limits for the production of fish in sea-cages, yet limited information exists to assess how environmental fluctuations modify the effects of stocking densities on the production ... -
Full production cycle, commercial scale culture of salmon in submerged sea-cages with air domes reduces lice infestation, but creates production and welfare challenges
Warren-Myers, Fletcher; Vågseth, Tone; Folkedal, Ole; Stien, Lars Helge; Fosse, Jan Olav; Dempster, Tim; Oppedal, Frode (Peer reviewed; Journal article, 2021)Structural modification of sea cages is continually changing to counter major production issues associated with commercial salmon farming. For example, snorkels and skirts are added to cages to reduce salmon lice infestations, ... -
Group Behavioural Responses of Atlantic Salmon (Salmo salar L.) to Light, Infrasound and Sound Stimuli
Bui, Samantha; Oppedal, Frode; Korsøen, Øyvind Johan; Sonny, Damien; Dempster, Tim (Journal article; Peer reviewed, 2013-05-17)Understanding species-specific flight behaviours is essential in developing methods of guiding fish spatially, and requires knowledge on how groups of fish respond to aversive stimuli. By harnessing their natural behaviours, ... -
High connectivity of salmon farms revealed by aggregation, residence and repeated movements of wild fish among farms
Uglem, Ingebrigt; Dempster, Tim; Bjørn, Pål Arne; Sanchez-Jerez, P.; Økland, Finn (Journal article; Peer reviewed, 2009-05-29)Marine fish farms are widespread in coastal waters throughout the world, yet how they modify the movement patterns of wild fish species is largely unknown. We determined the spatio-temporal distribution of saithe Pollachius ... -
High host densities dilute sea lice Lepeophtheirus salmonis loads on individual Atlantic salmon, but do not reduce lice infection success
Samsing, Francisca; Oppedal, Frode; Johansson, David; Bui, Samantha; Dempster, Tim (Journal article; Peer reviewed, 2014-12-02)Host density likely plays a key role in host−parasite interactions, but empirical evidence in marine ecosystems remains limited. Classical models predict a positive relationship between host density and parasite infection ... -
Hvordan unngå flytere ved heving av torskemerder
Korsøen, Øyvind Johan; Fosseidengen, Jan Erik; Dempster, Tim; Stien, Lars Helge; Kristiansen, Tore S. (Havforskningsnytt;Nr. 2 - 2011, Working paper, 2011)Oppdrettstorsk tåler en trykkreduksjon på maks 40 % dersom en skal være sikker på at svømmeblæren ikke løfter fisken til overflaten med buken i været. Etter en slik reduksjon av trykket bør det gå minst åtte timer før ...