Its decline appears to have been mediated by the oomycete Aphanomyces astaci
Schikora introduced in the 1970s along with the invasive American crayfish Pacifastacus leniusculus Dana; although asymptomatic in its original host,the fungus causes mortality in native Europeancrayfish (Holdich & Reeve, 1991; Kozubikova et al.,2009)