Crayfish plague affects juvenile survival and adult behaviour of invasive signal crayfish

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  • John Rhidian Thomas
    Cardiff University
  • Chloe Robinson
    Swansea University
  • Agata Mrugała
    Charles University, Prague
  • Amy Ellison
  • Emily Matthews
    Cardiff University
  • Sian Griffiths
    Cardiff University
  • Sofia Consuegra
    Swansea University
  • Jo Cable
    Cardiff University
The spread of invasive, non-native species is a key threat to biodiversity. Parasites can play a significant role by influencing their invasive host’s survival or behaviour, which can subsequently alter invasion dynamics. The North American signal crayfish (Pacifastacus leniusculus) is a known carrier of Aphanomyces astaci, an oomycete pathogen that is the causative agent of crayfish plague and fatal to European crayfish species, whereas North American species are considered to be largely resistant. There is some evidence, however, that North American species, can also succumb to crayfish plague, though how A. astaci affects such ‘reservoir hosts’ is rarely considered. Here, we tested the impact of A. astaci infection on signal crayfish, by assessing juvenile survival and adult behaviour following exposure to A. astaci zoospores. Juvenile signal crayfish suffered high mortality 4-weeks post-hatching, but not as older juveniles. Furthermore, adult signal crayfish with high infection levels displayed altered behaviours, being less likely to leave the water, explore terrestrial areas and exhibit escape responses. Overall, we reveal that A. astaci infection affects signal crayfish to a much greater extent than previously considered, which may not only have direct consequences for invasions, but could substantially affect commercially harvested signal crayfish stocks worldwide.


  • Aphanomyces astaci, behaviour, crayfish plague, invasive species, reservoir hosts, signal crayfish
Original languageEnglish
Pages (from-to)706-714
Issue number6
Early online date12 Feb 2020
Publication statusPublished - May 2020

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