Get access
Advertisement

Evidence for selective angling of introduced trout and their hybrids in a stocked brown trout population

Authors

  • M. Mezzera,

    1. Division of Population Genetics, Institute of Zoology, University of Berne, Baltzerstrasse 6, CH-3012 Berne, Switzerland
    Search for more papers by this author
  • C. R. Largiadèr

    Corresponding author
    1. Division of Population Genetics, Institute of Zoology, University of Berne, Baltzerstrasse 6, CH-3012 Berne, Switzerland
      Author to whom correspondence should be addressed. Tel.: +41 31 631 45 13; fax: +41 31 631 48 88. email: largiader@zoo.unibe.ch
    Search for more papers by this author

Author to whom correspondence should be addressed. Tel.: +41 31 631 45 13; fax: +41 31 631 48 88. email: largiader@zoo.unibe.ch

Abstract

Comparisons of the genetic composition of brown trout Salmo trutta captured by anglers and by electrofishing based on three diagnostic microsatellite loci provided strong evidence that angling is selective in a stocked brown trout population. At two sites, anglers caught significantly younger trout and proportionally more introduced hatchery trout and hybrids than were observed in electrofishing surveys. Selective angling, in combination with a small legal catch size, may have considerably eliminated introduced trout and hybrids before spawning at the study sites, and thus may have reduced the introgression of alien genes into the local gene pool. Angling can be an important factor influencing the genetic structure of fish populations and should be taken into account in studies of introgressive hybridization in stocked fish populations and their management. In this study, demographic consequences of stocking were not assessed. Thus, even though the genetic consequences of stocking may be minimal or largely reversible through angling, resource competition between native and introduced trout, until they reach legal catch size, is expected to have a negative effect on the productivity of the indigenous trout population.

Get access to the full text of this article

Ancillary