Crayfish are significantly smaller, freshwater cousins of the lobster. Signal crayfish are not a native species and, since their importation from the Western United States, have colonised many waterways in the UK, pushing out the native white-claw. For this reason, the white-claw is now a protected species. When sourcing crayfish, remember that you should be sold signal crayfish, which have a distinctive red underside.
Crayfish are best eaten from late spring to late autumn. Weather conditions affect their availability and cost, as does the spawning season (when the flesh of shellfish softens and has less flavour). Some species migrate, so might only be available frozen in certain months.
Crayfish are generally suitable for the same treatment as large prawns or langoustines. With such sweet meat, simplicity is key: eat cooked fresh crayfish with mayonnaise and a dash of lemon juice, or fry them in paprika, garlic and plenty of olive oil and stir into pasta. Chef Richard Corrigan recommends boiling crayfish in salted water with a healthy dose of bronze fennel, for flavour, and serving them alongside thin slices of buttered granary bread. Crayfish are also delicious in risottos, soups and stews.