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dc.contributor.authorOpdal, Anders Frugård
dc.contributor.authorJørgensen, Christian
dc.PublishedGlobal Change Biology 2015, 21(4):1521-1530eng
dc.description.abstractHarvesting may be a potent driver of demographic change and contemporary evolution, which both may have great impacts on animal populations. Research has focused on changes in phenotypic traits that are easily quantifiable and for which time series exist, such as size, age, sex, or gonad size, whereas potential changes in behavioural traits have been under-studied. Here, we analyse potential drivers of long-term changes in a behavioural trait for the Northeast Arctic stock of Atlantic cod Gadus morhua, namely choice of spawning location. For 104 years (1866–1969), commercial catches were recorded annually and reported by county along the Norwegian coast. During this time period, spawning ground distribution has fluctuated with a trend towards more northerly spawning. Spawning location is analysed against a suite of explanatory factors including climate, fishing pressure, density dependence, and demography. We find that demography (age or age at maturation) had the highest explanatory power for variation in spawning location, while climate had a limited effect below statistical significance. As to potential mechanisms, some effects of climate may act through demography, and explanatory variables for demography may also have absorbed direct evolutionary change in migration distance for which proxies were unavailable. Despite these caveats, we argue that fishing mortality, either through demographic or evolutionary change, has served as an effective driver for changing spawning locations in cod, and that additional explanatory factors related to climate add no significant information.en_US
dc.rightsAttribution CC BY-NCeng
dc.subjectGadus morhuaeng
dc.subjectNortheast Arctic codeng
dc.titleLong-term change in a behavioural trait: truncated spawning distribution and demography in Northeast Arctic coden_US
dc.typePeer reviewed
dc.typeJournal article
dc.rights.holderCopyright 2014 The Authorsen_US
dc.subject.nsiVDP::Matematikk og naturvitenskap: 400::Zoologiske og botaniske fag: 480::Zoogeografi: 486
dc.subject.nsiVDP::Mathematics and natural scienses: 400::Zoology and botany: 480::Zoogeography: 486

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