250. The basic methods of killing in trout farming are by suffocation, by a blow to the back of the head, or by electric stunning followed by evisceration. The last two methods are only used on small scale retail outlets and most of the larger farms simply drain water away from the fish leaving them to die of anoxia or carbon dioxide poisoning. There is an increasing awareness in the industry of the need to develop humane methods of killing trout. Some farmers have tried other methods such as supercooling and carbon dioxide stunning but these are only effective if followed by immediate evisceration. Trout taken out of water and cooled on ice take much longer to die but remain sensible to stimuli (Kestin, Wotton and Gregory, 1991) and we recommend that this method should be prohibited.