title: Divergent trends in anadromous salmonid populations in Norwegian and Scottish rivers.
abstract: The Atlantic salmon (Salmo salar) is a charismatic anadromous fish of high conservation and economic value. Concerns have been expressed regarding the long-term viability of fisheries throughout the species's distributional range because of abundance variations that cannot currently be explained or predicted. Here, we analyse long-term catch data obtained over a wide geographical range and across a range of spatial subscales to understand more fully the factors that drive population abundance. We use rod catch data from 84 Norwegian rivers over 125 years (1876-2000) and 48 Scottish rivers over 51 years (1952-2002). The temporal correlation in catches is very long-term, with trends persisting over several decades. The spatial correlation is relatively short-range, indicating strong local-scale effects on catch. Furthermore, Scottish salmon populations exhibit recent negative trends in contrast to some more positive trends in Norway--especially in the north.
authors.affiliation: Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, PO Box 1066 Blindern, 0316 Oslo, Norway. avollest@bio.uio.no
authors.forename: Leif Asbjørn
authors.initials: LA
authors.lastname: Vøllestad
authors.forename: David
authors.initials: D
authors.lastname: Hirst
authors.forename: Jan Henning
authors.initials: JH
authors.lastname: L'Abée-Lund
authors.forename: John D
authors.initials: JD
authors.lastname: Armstrong
authors.forename: Julian C
authors.initials: JC
authors.lastname: MacLean
authors.forename: Alan F
authors.initials: AF
authors.lastname: Youngson
authors.forename: Nils Chr
authors.initials: NC
authors.lastname: Stenseth
mesh_terms: D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D009664:Norway; D011157:Population Dynamics; D020317:Salmo salar / Q000502:physiology*; D012606:Scotland; D013997:Time Factors