Clare visited the Egg on Saturday and shared her photo of a crayfish living in Southmere Lake, but my knowledge of the species is very limited. Is this an increasingly rare native White Clawed Crayfish, or one of the  Signal Crayfish introduced from North America? The Signal Crayfish carries a ‘plague’ that is wiping out our native species that has seen its population decline by about 80% in the last ten years. Can anyone tell me which this is?