Crab

Crabs are sold live, cooked, and raw (or green). Blue swimmer crabs and spanner crabs are usually sold cooked, as they do not live long after capture. Mud crabs are best bought live, though care should be taken, as they can inflict severe injury with their claws.
Crabs are best cooked in water containing 25gm of salt per litre. The RSPCA recommends live crustaceans be killed as humanely as possible, specifically by placing the animal in the refrigerator or freezer until it is asleep, and then killing it by splitting it or spiking it to destroy the nerve centres.