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Process-based modelling of decadal trends in growth, survival, and smolting of wild salmon (Salmo salar) parr in a Scottish upland stream

Gurney, William S.C. and Bacon, Philip J. and Tyldesley, Graham and Youngson, Alan F. (2008) Process-based modelling of decadal trends in growth, survival, and smolting of wild salmon (Salmo salar) parr in a Scottish upland stream. Canadian Journal of Fisheries and Aquatic Sciences, 65. pp. 2606-2622. ISSN 1205-7533

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    Abstract

    This paper reports a new model of the freshwater stages of an anadromous fish, at the core of which is a stochastic description of the size-at-age dynamics of a growing cohort. Emigration is assumed to require the individual to exceed a threshold size at a critical time of year, thus making the distributions of survival to, and age at, smolting emergent properties of the model. The model is applied to a long-term data set on juvenile Atlantic salmon (Salmo salar) in the Girnock Burn, Scotland, to understand the role played by decadal temperature trends in generating changes in smolt production and age distribution. We conclude that changes in age at smolting are compatible with causation by shifts in the temperature regime. However, the large attenuation between a dramatic fall in spawner numbers and a relatively minor diminution in total smolt production does not result from the physiological effects of temperature but is rather a result of strongly density-dependent mortality between the deposition of ova and the appearance of catchable fry the following summer.

    Item type: Article
    ID code: 14044
    Keywords: modelling, decadal trends, salmon, smolt production, age distribution, Mathematics
    Subjects: Science > Mathematics
    Department: Faculty of Science > Mathematics and Statistics
    Faculty of Science > Mathematics and Statistics > Statistics and Modelling Science
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      Depositing user: Mrs Ann Lynch
      Date Deposited: 14 Jan 2010 18:54
      Last modified: 18 Mar 2012 15:44
      URI: http://strathprints.strath.ac.uk/id/eprint/14044

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