Divergent trends in anadromous salmonid populations in Norwegian and Scottish rivers.
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.
Vøllestad
Leif Asbjørn
LA
Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biology, University of Oslo, PO Box 1066 Blindern, 0316 Oslo, Norway. avollest@bio.uio.no
Hirst
David
D
L'Abée-Lund
Jan Henning
JH
Armstrong
John D
JD
MacLean
Julian C
JC
Youngson
Alan F
AF
Stenseth
Nils Chr
NC
D025041:Animal Migration / Q000502:physiology*; D000818:Animals; D009664:Norway; D011157:Population Dynamics; D020317:Salmo salar / Q000502:physiology*; D012606:Scotland; D013997:Time Factors