I think as long as you put them(live) in tap water for 12hrs or so they will effectively clean themselves out.Then drop em straight in boiling water. Taste like chicken.
But does trapping them help the native species, or are they doomed to extinction?
They transmit crayfish plague, a disease caused by a fungus which affects our native white clawed crayfish, which is protected under both UK and European law, and is classed as globally threatened.
This man knows a thing or two about crayfish...There's a recipe in his first book - ours is packed away unfortunately as our kitchen is being ripped apart otherwise I would've scanned it.
No joy with the trap . I think the drop in temps or the high stream flow has sent them all into their burrows, as I couldn't find any under any rocks either.