Investigating the threat of non-native North American signal crayfish (Pacifastacus leniusculus) to salmon redds


Z. F. Gladman, Institute of Biodiversity, Animal Health and Comparative Medicine, Graham Kerr Building, University of Glasgow, Glasgow, G12 8QQ, UK. E-mail:


  1. To test their ability to detect and excavate Atlantic salmon eggs (Salmo salar) in an artificial redd, North American signal crayfish (Pacifastacus leniusculus) were exposed to three successive experimental treatments.
  2. Crayfish successfully detected and excavated buried fish but were unable to detect buried salmon eggs, despite significant opportunity.
  3. The results strongly suggest that signal crayfish do not present a threat to Atlantic salmon via egg predation. In the wild, however, the vulnerability of redds may vary according to a range of biotic and abiotic factors.

Copyright © 2011 John Wiley & Sons, Ltd.