Temporal and spatial variation in recreational catches of anadromous brown trout, Salmo trutta, in Norwegian rivers
Overall, it has been shown that production of diadromous fishes is declining within the North Atlantic basin reaching the lowest levels in recent years compared to their historic baselines. However, these decreases in abundance, ascribed to numerous factors, are species specific and might differ across each species’ distributional range. Here we used recreational angling catch data for anadromous brown trout Salmo trutta in multiple Norwegian rivers having relatively high annual reported catches to elucidate its spatio-temporal patterns since the late 1960s. Rivers lacking or having very low annual catch reports for various reasons were not included. The catches have increased at a rate of ~15% per decade though trends varied geographically with larger increases at northern latitudes and decreases at more southern latitudes. Larger catches were obtained at elevated levels of runoff during summer and early autumn, and at positive NAO phase during the year preceding the catch. Additionally, higher average catch and more pronounced increasing temporal trends in catches were obtained in larger rivers with shallower slopes, respectively. Furthermore, stronger relationships with runoff occurred in steeper rivers. Other factors such as Gyrodactylosis or fish farming seemed not to have detectable signals in the overall pattern of brown trout catches.
KeywordsBrown trout Catches Discharge Sea surface temperature NAO Habitat characteristics Norway
We acknowledge Stein Beldring and Sille Marie Myreng at Norwegian Water Resources and Energy Directorate for computing water discharges and glacier area, respectively. This study is part of the Norwegian Research Council Project no 183989/S30. J.O. acknowledges additional funding from the Norwegian Water Resources and Energy Directorate (NVE), and support by a ‘Junta para la Ampliación de Estudios’ fellowship (JAE-Doc programme 2011) from the CSIC and ESF. Three anonymous reviewers greatly improved earlier versions of this manuscript.
- Aas, Ø., S. Einum, A. Klemetsen & J. Skurdal, 2011. Atlantic Salmon Ecology. Blackwell Publishing Ltd, Oxford.Google Scholar
- Alm, G., 1959. Connection between maturity, size and age in fishes. Report from the Institute of Freshwater Research. Drottninghold 40: 5–145.Google Scholar
- Eldøy, S. H., J. G. Davidsen, E. B. Thorstad, F. Whoriskey, K. Aarestrup, T. F. Næsje, L. Rønning, A. D. Sjursen, A. H. Rikardsen & J. V. Arnekleiv, 2015. Marine migration and habitat use of anadromous brown trout (Salmo trutta). Canadian Journal of Fisheries and Aquatic Sciences 72: 1366–1378.CrossRefGoogle Scholar
- Finstad, B. & P. A. Bjørn, 2011. Present status and implications of salmon lice on wild salmonids in Norwegian coastal zones. In Jones, S. & R. Beamish (eds), Salmon Lice: An Integrated Approach to Understanding Parasite Abundance and Distribution. Wiley, Oxford.Google Scholar
- Harris, P. D., L. Bachmann & T. A. Bakke, 2011. The parasites and pathogens of the Atlantic salmon: Lessons from Gyrodactylus salaris. In Aas, Ø., E. S. A. Klemetsen & J. Skurdal (eds), Atlantic Salmon Ecology. Blackwell Publishing Ltd., Oxford.Google Scholar
- Hindar, K., J. A. Hutchings, O. H. Diserud & P. Fiske, 2011. Stock, recruitment and exploitation. In Aas, Ø., E. S. A. Klemetsen & J. Skurdal (eds), Atlantic Salmon Ecology. Blackwell Publishing Ltd., Oxford.Google Scholar
- Hurrell, J. W., Y. Kushnir, G. Ottersen & M. Visbeck, 2003. An overview of the North Atlantic Oscillation. In: J. W. Hurrell, Y. Kushnir, G. Ottersen & M. Visbeck (eds), The North Atlantic Oscillation: Climatic Significance and Environmental Impact. Geophysical Monograph 134, American Geophysical Union, Washington D.C.Google Scholar
- Ibañez, F. & M. Etienne, 1992. Le filtrage des séries chronologiques par l’analyse en composantes principales de processus (ACPP). Journal de Recherche Océanographique 16: 27–33.Google Scholar
- ICES, 2013. Report of the workshop on sea trout (WKTRUTTA), 12–14 November, Copenhagen, Denmark. ICES CM 2013/SSGEF:15, 242 pp.Google Scholar
- ICES, 2015. Report of the working group on North Atlantic salmon (WGNAS), 17–26 March, Moncton, Canada. ICES CM 2015/ACOM:09, 332 pp.Google Scholar
- Jensen, A. J., B. Finstad, P. Fiske, N. A. Hvidsten, A. H. Rikardsen & L. Saksgård, 2012. Timing of smolt migration in sympatric populations of Atlantic salmon (Salmo salar), brown trout (Salmo trutta), and Arctic char (Salvelinus alpinus). Canadian Journal of Fisheries and Aquatic Sciences 69: 711–723.CrossRefGoogle Scholar
- Klemetsen, A., P.-A. Amundsen, J. B. Dempson, B. Jonsson, N. Jonsson, M. F. O’Connell & E. Mortensen, 2003. Atlantic salmon Salmo salar L., brown trout Salmo trutta L. and Arctic charr Salvelinus alpinus (L.): a review of aspects of their life histories. Ecology of Freshwater Fish 12: 1–59.CrossRefGoogle Scholar
- L’Abée-Lund, J. H. & L. A. Vøllestad, 2017. Life history plasticity in anadromous brown trout: a Norwegian perspective. In: J. Lobón-Cerviá & N. Sanz (eds), Brown trout: biology, ecology and management. Blackwell Publishing Ltd., Oxford.Google Scholar
- Legendre, P. & L. Legendre, 1998. Numerical ecology, 2nd ed. Elsevier Science, Amsterdam.Google Scholar
- Otero, J., A. J. Jensen, J. H. L’Abée-Lund, N. C. Stenseth, G. O. Storvik & L. A. Vøllestad, 2011. Quantifying the ocean, freshwater and human effects on year-to-year variability of one-sea-winter Atlantic salmon using multiple long time series from Norwegian rivers. PLoS ONE 6: e24005.CrossRefPubMedPubMedCentralGoogle Scholar
- Quinn, T. P., 2005. The Behavior and Ecology of Pacific Salmon and Trout. University of Washington Press, Seattle, WA.Google Scholar
- R Development Core Team, 2016. R: A language and environment for statistical computing. In: R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, http://R-project.org.
- Rosseland, B. O. & F. Kroglund, 2011. Lessons from acidification and pesticides. In Aas, Ø., E. S. A. Klemetsen & J. Skurdal (eds), Atlantic Salmon Ecology. Blackwell Publishing Ltd., Oxford.Google Scholar
- Sægrov, H., K. Urdal, B. A. Hellen, S. Kalas & S. J. Saltveit, 2001. Estimating carrying capacity and presmolt production of Atlantic salmon (Salmo salar) and anadromous brown trout (Salmo trutta) in west Norwegian rivers. Nordic Journal of Freshwater Research 75: 99–108.Google Scholar
- Stenseth, N. C., G. Ottersen, J. W. Hurrell, A. Mysterud, M. Lima, K.-S. Chan, N. G. Yoccoz & B. Ådlandsvik, 2003. Studying climate effects on ecology through the use of climate indices: the North Atlantic Oscillation, El Niño Southern Oscillation and beyond. Proceedings of the Royal Society of London B 270: 2087–2096.CrossRefGoogle Scholar
- Straile, D., D. M. Livingstone, G. A. Weyhenmeyer & D. G. George, 2003. The response of freshwater ecosystems to climate variability associated with the North Atlantic Oscillation. In: J. W. Hurrell, Y. Kushnir, G. Ottersen & M. Visbeck (eds), The North Atlantic Oscillation: Climatic Significance and Environmental Impact. Geophysical Monograph 134, American Geophysical Union, Washington D.C.Google Scholar
- Thorstad, E. B., C. D. Todd, I. Uglem, P. A. Bjørn, P. G. Gargan, K. W. Vollset, E. Halttunen, S. Kålås, M. Berg & B. Finstad, 2015. Effects of salmon lice Lepeophtheirus salmonis on wild sea trout Salmon trutta – a literature review. Aquaculture Environment Interactions 7: 91–113.CrossRefGoogle Scholar
- van Etten, J., 2015. gdistance: Distances and routes on geographical grids. R package version 1.1.-9. https://CRAN.R-project.org/package=gdistance.