Non-native, invasive crayfish are a huge problem in the UK. Species such as Signal crayfish have slowly spread through the country’s rivers and streams, damaging banks and preying on native species. So what can we do to stop them? One method which is often suggested is trapping. You may have seen celebrity chefs and wild food experts fishing for Signal crayfish, extolling the virtues of trapping as a way to help conserve White-claws and other native species and to get a free meal.