The role of growth history in determining age and size at maturation in exploited fish populations

Authors

  • Anna Kuparinen,

    1. Department of Biological and Environmental Sciences, University of Helsinki, PO Box 65, FI-00014 Helsinki, Finland
    2. Department of Mathematics and Statistic, University of Helsinki, PO Box 68, FI-00014 Helsinki, Finland
    Search for more papers by this author
  • Robert B O’Hara,

    1. Department of Mathematics and Statistic, University of Helsinki, PO Box 68, FI-00014 Helsinki, Finland
    Search for more papers by this author
  • Juha Merilä

    1. Department of Biological and Environmental Sciences, University of Helsinki, PO Box 65, FI-00014 Helsinki, Finland
    Search for more papers by this author

  • Ghoti papers
    Ghoti aims to serve as a forum for stimulating and pertinent ideas. Ghoti publishes succinct commentary and opinion that addresses important areas in fish and fisheries science. Ghoti contributions will be innovative and have a perspective that may lead to fresh and productive insight of concepts, issues and research agendas. All Ghoti contributions will be selected by the editors and peer reviewed.
    Etymology of Ghoti
    George Bernard Shaw (1856-1950), polymath, playwright, Nobel prize winner, and the most prolific letter writer in history, was an advocate of English spelling reform. He was reportedly fond of pointing out its absurdities by proving that ‘fish’ could be spelt ‘ghoti’. That is: ‘gh’ as in ‘rough’, ‘o’ as in ‘women’ and ‘ti’ as in palatial.

Anna Kuparinen, Department of Biological and Environmental Sciences, University of Helsinki, PO Box 65, FI-00014 Helsinki, Finland
Tel.: +358 40 7313120
Fax: +358 91 9157694
E-mail: anna.kuparinen@helsinki.fi

Abstract

Recently, a great deal of attention has been focused on investigating whether decreased ages and sizes at maturation in exploited fish populations could be evolutionary responses to selective fishing. To this end, the main focus has been on isolating the effects of growth changes from the process of maturation, but little effort has been invested in assessing how growth actually affects ages and sizes at maturation in a population. Here, we develop a probabilistic description of the process of maturation, which makes explicit the mathematical links between maturation, growth and the probabilistic maturation reaction norm. Apart from providing a mathematically explicit yet heuristically simple framework for assessing the role of growth in the age and size at maturation, we demonstrate by simulation that changes in growth rates can result in considerable shifts in the age and size at maturation. Focusing more attention on growth histories of individuals would provide a better position to understand the processes constituting phenotypic shifts in the age and size at maturation and help in disentangling environmentally induced plastic changes in maturation from those caused by evolutionary responses to fisheries-induced selection.

Ancillary