The situation of native crayfish in France has become alarming in recent decades due to various factors, among them habitat destruction and degradation of water quality, but also increasing of introductions of non-native crayfish species in recent times.
A recent scientific paper reported the first record of the invasive rusty crayfish Faxonius rusticus (Girard, 1852) in France and in Europe. The species was discovered accidentally by a fisherman in 2019 in a pond in southern France.
Faxonius rusticus is native to the Ohio River watershed, including southwestern Ohio, northern Kentucky, southeastern Indiana and northern Tennessee. The distribution of this species outside its native area has expanded rapidly due to introductions by human activities, including ornamental trade and aquaculture.
F. rusticus is known to be very invasive, with a high dispersal potential and some individuals were already observed in the adjacent brooks, three kilometers downstream of the pond.
For his aggressivity, reproduction ability and Aphanomyces astaci infection rate (a deadly fungus for native crayfish), this species seems to be worse than other invasive crayfish such as Pacifastacus leniusculus and Faxonius immunis present in headwater system in France. The presence of F. rusticus in France is therefore alarming for the preservation of the native crayfish Austropotamobius pallipes, considered as vulnerable by IUCN.
Pond draining and intensive trapping effort, are in place to eradicate this population before its spread to major French catchments.
To find out more you can read the article.
You can also consult the species factsheet.