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dc.contributor.authorStrand, Hans Kristian
dc.contributor.authorPedersen, Torstein
dc.contributor.authorChristie, Hartvig C
dc.contributor.authorMoy, Frithjof Emil
dc.date.accessioned2020-07-10T08:14:38Z
dc.date.available2020-07-10T08:14:38Z
dc.date.issued2020-03-06
dc.description.abstractShorthorn sculpin (<i>Myoxocephalus scorpius</i>) and large cod (300–400 g body weight) are important predators on newly settled 0-group cod (<i>Gadus morhua</i>) and saithe (<i>Pollachius virens</i>) in Porsangerfjorden in northern Norway. The Atlantic wolffish (<i>Anarhichas lupus</i>) used to be abundant but is now very rare in the fjord. Video recorded experiments showed that interactions between shorthorn sculpins, wolffish and large cod affected predation rates on small 0-group cod and saithe in tanks with a gravel, cobble and seaweed (<i>Fucus serratus</i>) substrate. We found that sculpins were unable to catch 0-group specimens when they were the only predatory species in the experimental tank and the lights were left on 24 h a day (to simulate the midnight sun), and that they did not even attempt to catch them. The addition of a large cod to the tank increased sculpin attack rates and predation success significantly.<p><p> The “cod effect” was due to 0-group specimens avoiding attacks by escaping into the cobbles or vegetation, were they could be more easily reached by the sculpins. When tanks were supplemented with a wolffish in addition to the cod, both sculpin and cod predation success was lowered by approximately 50% in the 24-h light regime. When the experimental setup was changed to a day/night light cycle, however, the wolffish presence had no effect. Also, sculpins in tanks without cod and wolffish went from consuming zero to 29% of the 0-group specimens in the tank when the light regime went from 24-h light to day/night. Sculpins and cod were most effective predators on 0-group cod and saithe at dusk/night/dawn, and the presence of a cruising predator like cod increased sculpin predation success and probably <i>vice versa</i>.<p><p> The experimental data indicate that rebuilding wolffish stocks in the fjord system may make the bottom substrate more protective for 0-group specimens of cod and saithe, by limiting the foraging volume of an effective bottom-dwelling 0-group predator like the sculpin. Further field and lab studies must be conducted before the reported findings optionally can be turned into a management advice.en_US
dc.identifier.citationStrand HK, Pedersen TP, Christie Hc, Moy FE. Synergism between cruising cod and ambush sculpin predators on 0-group gadoids is modified by daylight cycle and presence of aggressive wolffish. Journal of Experimental Marine Biology and Ecology. 2020;526en_US
dc.identifier.cristinIDFRIDAID 1812233
dc.identifier.doi10.1016/j.jembe.2020.151356
dc.identifier.issn0022-0981
dc.identifier.issn1879-1697
dc.identifier.urihttps://hdl.handle.net/10037/18800
dc.language.isoengen_US
dc.publisherElsevieren_US
dc.relation.journalJournal of Experimental Marine Biology and Ecology
dc.relation.projectIDNorges forskningsråd: 217663en_US
dc.relation.projectIDinfo:eu-repo/grantAgreement/RCN/?/217663/Norway/?/?/en_US
dc.rights.accessRightsopenAccessen_US
dc.rights.holderCopyright 2020 The Author(s)en_US
dc.subjectVDP::Mathematics and natural science: 400::Zoology and botany: 480::Marine biology: 497en_US
dc.subjectVDP::Matematikk og Naturvitenskap: 400::Zoologiske og botaniske fag: 480::Marinbiologi: 497en_US
dc.titleSynergism between cruising cod and ambush sculpin predators on 0-group gadoids is modified by daylight cycle and presence of aggressive wolffishen_US
dc.type.versionpublishedVersionen_US
dc.typeJournal articleen_US
dc.typeTidsskriftartikkelen_US
dc.typePeer revieweden_US


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