Abstract
Transmission of the crayfish plague pathogen Aphanomyces astaci endangers native European crayfish. This pathogen, spread mainly by its natural hosts, North American crayfish, has also been detected in the aquarium trade in Europe.
As the trade in ornamental crayfish is nowadays considered a key introduction pathway of non-European crayfish, it may contribute to crayfish plague spread. Non-American crayfish have been assessed as highly susceptible to the pathogen, and thus unlikely to participate in A. astaci spread from aquarium facilities.
However, moderate resistance to this disease has been suggested for the Australian yabby Cherax destructor. This widely traded crayfish species exhibits high potential to establish in Central Europe, and has been assessed as a high-risk species with regards to its invasiveness.
We investigated resistance of juvenile C. destructor towards three A. astaci strains differing in virulence (representing genotype groups A, B and E), present in Central European waters. Cherax destructor was exposed to two doses of A. astaci zoospores (10 and 100 spores ml(-1)) and its mortality was further compared with that of the juvenile European noble crayfish Astacus astacus.
While some survival among C. destructor individuals was observed after exposure to the least virulent A. astaci strain (genotype group A), total mortality of Australian crayfish was noted after infection with the two more virulent strains. However, in contrast to A. astacus, the mortality of C. destructor was significantly delayed.
These results suggest that under favourable conditions C. destructor may contribute to crayfish plague spread in Central Europe.