Meaning of signal crayfish in English:
signal crayfish
noun
A freshwater crayfish, Pacifastacus leniusculus (family Astacidae), with a bright patch on the underside of each claw, native to the western United States and introduced in Europe and Japan, where it now threatens native wildlife.
Origin
1980s; earliest use found in Ambio. After Swedish signalkräfta.
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