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dc.contributor.authorWright, Daniel William
dc.contributor.authorGeitung, Lena
dc.contributor.authorKarlsbakk, Egil
dc.contributor.authorStien, Lars Helge
dc.contributor.authorDempster, Timothy David
dc.contributor.authorOldham, Tina
dc.contributor.authorNola, Velimir
dc.contributor.authorOppedal, Frode
dc.PublishedWright DW, Geitung L, Karlsbakk E, Stien LH, Dempster TD, Oldham T, Nola V, Oppedal F. Surface environment modification in Atlantic salmon sea-cages: Effects on amoebic gill disease, salmon lice, growth and welfare. Aquaculture Environment Interactions. 2018;10:255-265eng
dc.description.abstractSurface environment modification is a potential parasite control strategy in Atlantic salmon sea-cage farming. For instance, a temporary low salinity surface layer in commercial-scale snorkel sea-cages has coincided with reduced amoebic gill disease (AGD) levels after an outbreak. We tested if a permanent freshwater (FW) surface layer in snorkel sea-cages would lower AGD and salmon lice levels of stock relative to snorkel cages with seawater (SW) only and standard production cages with no snorkels. Triplicate cages of each type with 2000 post-smolts were monitored in autumn to winter for 8 wk and sampled 4 times. Lower proportions of individuals with elevated AGD-related gill scores were registered in SW and FW snorkel cages compared to standard cages; however, these proportions did not differ between SW and FW snorkel cages. Individuals positive for AGD-causing Paramoeba perurans were reduced by 65% in FW snorkel relative to standard cages, but values were similar between SW snorkel cages and other types. While total lice burdens were reduced by 38% in SW snorkel compared to standard cages, they were unchanged between FW snorkel and other cage types. Fish welfare and growth were unaffected by cage type. Surface activity was detected in all cages; however, more surface jumps were recorded in standard than snorkel cages. Overall, fish in FW snorkel cages appeared to reside too little in freshwater to consistently reduce AGD levels and salmon lice compared to SW snorkel cages. Further work should test behavioural and environmental manipulations aimed at increasing freshwater or low salinity surface layer use.en_US
dc.rightsAttribution CC BYeng
dc.subjectCage environmenteng
dc.subjectSalmo Salareng
dc.subjectLepeophtheirus salmoniseng
dc.subjectParamoeba peruranseng
dc.subjectParasite controleng
dc.titleSurface environment modification in Atlantic salmon sea-cages: Effects on amoebic gill disease, salmon lice, growth and welfareen_US
dc.typePeer reviewed
dc.typeJournal article
dc.rights.holderCopyright 2018 The Author(s)en_US
dc.source.journalAquaculture Environment Interactions
dc.relation.projectNorges forskningsråd: 267800
dc.relation.projectNorges forskningsråd: 256318
dc.identifier.citationAquaculture Environment Interactions. 2018, 10, 255-265.

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