Anadromy in brown trout (Salmo trutta): A review of the relative roles of genes and environmental factors and the implications for management and conservation

dc.contributor.authorFerguson, Andy
dc.contributor.authorReed, Thomas E.
dc.contributor.authorMcGinnity, Philip
dc.contributor.authorProdöhl, Paolo A.
dc.contributor.editorHarris, Graham
dc.contributor.funderEuropean Research Councilen
dc.contributor.funderHorizon 2020en
dc.date.accessioned2021-07-01T11:41:30Z
dc.date.available2021-07-01T11:41:30Z
dc.date.issued2016-10
dc.date.updated2021-07-01T10:14:52Z
dc.description.abstractWhile many brown trout (Salmo trutta) populations spend their entire life cycle in freshwater, especially as river-lake migrants or river residents, others show facultative anadromy. That is, some trout migrate to sea while other individuals of the same population remain within their natal river. Sea trout can give rise to resident offspring and vice versa, although there is a strong tendency to track the parental life history. Anadromy delivers better feeding and thus larger size, which results in higher fecundity in females, enhanced mate choice, and other reproductive benefits. River residence, more prevalent in males as anadromy conveys fewer benefits, can give higher survival and avoids the energy expenditure required by anadromy. Overall, the costs and benefits of anadromy versus residency, measured in terms of survival and reproduction, are finely balanced and small changes to the cost-benefit equation can lead to evolutionary changes in life history. The decision to be anadromous or resident is a quantitative threshold trait, controlled by multiple genes and environmental factors. The dichotomous nature of the trait is postulated to be the result of the environmentally influenced physiological condition (e.g. energy status) relative to a genetically determined threshold. Anadromy ensues when an individual’s condition fails to meet the threshold level, which varies between sexes and among individuals and populations. Environmental factors and genetic architecture may also directly influence life history, e.g., by altering gene expression. A strong genetic influence on the anadromy decision means that facultative anadromy can be altered by natural selection driven by changes such as differential exploitation, stocking with farm-reared brown trout, partial barriers to migration, and changes in climate, and freshwater and marine productivity, together with parasite, pathogen and predator abundance resulting in reduced marine survival and growth. Further studies of the factors determining life history choice, together with multiple population estimates of heritability and differential reproductive success (fitness), are required to understand fully the impact of natural and anthropogenic environmental changes on sea trout dynamics.en
dc.description.statusPeer revieweden
dc.description.versionAccepted Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationFerguson, A., Reed, T. E, McGinnity, P. and Prodohl, P. (2016) 'Anadromy in brown trout (Salmo trutta): A review of the relative roles of genes and environmental factors and the implications for management and conservation', in Harris, G. (ed.) Sea Trout: from Science to Management, Proceedings of the 2nd International Sea Trout Symposium, Dundalk, Ireland, 20-22 October, pp. 1-40. isbn: 9781788035354en
dc.identifier.endpage40en
dc.identifier.isbn9781788035354
dc.identifier.startpage1en
dc.identifier.urihttps://hdl.handle.net/10468/11522
dc.language.isoenen
dc.publisherTroubador Publishing Ltd.en
dc.relation.ispartofSea Trout: from Science to Management (Proceedings of the 2nd International Sea Trout Symposium, Dundalk, Ireland, October 2015)
dc.relation.projectinfo:eu-repo/grantAgreement/EC/H2020::ERC::ERC-STG/639192/EU/Alternative life histories: linking genes to phenotypes to demography/ALHen
dc.relation.urihttp://seatroutsymposium.org/proceedings/
dc.subjectSea trouten
dc.subjectRiver resident trouten
dc.subjectQuantitative threshold traiten
dc.subjectPhysiological conditionen
dc.subjectSexual maturationen
dc.subjectParental effectsen
dc.titleAnadromy in brown trout (Salmo trutta): A review of the relative roles of genes and environmental factors and the implications for management and conservationen
dc.typeBook chapteren
dc.typeConference itemen
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