Signal crayfish may have no relationship with mushrooms, but are just as delicious as a wild ingredient and really easy to catch . . .
It is probably no exaggeration to say that most English canals, rivers and lakes now teem with alien signal crayfish. These originally come from America, but were brought here in the 1970s as ‘freshwater lobster’. Some soon escaped and they are now a serious pest, not least because they carry a disease which is fatal to our native white clawed species.
In other words, harvesting these monstrous-looking beasts not only yields a delicious meal, but is a small blow on behalf of a threatened native. It is almost certainly too late to eradicate them completely, but at least guilt-free. Catching signals is easy: lower a banana-baited mesh-covered bicycle wheel into a river, wait 10 minutes and extract. Better still, buy a collapsible fish trap (see ebay) and insert a perforated foil cat food sachet. Obviously you need the landowner’s permission, must never catch native crayfish and technically need a licence, so at least in theory you should check with the Environment Agency (see http://www.environment-agency.gov.uk). In practice, however, you can catch these miniature aquatic monsters with a clean conscience.
Opinions are divided on humane dispatch. Some say dropping cold-blooded crustaceans into boiling water is painless, but others prefer to kill them with a stab to the head. In either case, your environmental gesture is best served with garlic butter, herb mayonnaise or (my favourite) dished up on basmati rice, smothered with a rich masala sauce and a warm naan.