Editing Signal crayfish (section)

{{Short description|Species of crustacean}}
{{Speciesbox
|name = ''Pacifastacus leniusculus''
|image = Signal crayfish female Pacifastacus leniusculus.JPG
|status = LC
|status_system = IUCN3.1
|status_ref = <ref name=IUCN/>
|genus = Pacifastacus
|species = leniusculus
|authority = ([[James Dwight Dana|Dana]], 1852)<ref>{{ITIS|taxon=''Pacifastacus leniusculus'' (Dana, 1852) |id=97326|access-date=December 18, 2019}}</ref>
}}

The '''signal crayfish''' ('''''Pacifastacus leniusculus''''') is a species of [[crayfish]] indigenous to [[North America]]. Introduced to Europe in the 1960s to supplement the North European ''[[Astacus astacus]]'' fisheries, which were being damaged by [[crayfish plague]], it was subsequently discovered that the signal was itself a carrier of that disease. Consequently, the signal crayfish is now considered an [[invasive species]] across Europe, Japan, and California, having displaced the native species in these regions.