when they filet them they basically just slap them down on the cutting board alive, evescerate them, and slice each side down to the rib bones. considering the brain and spinal column are untouched and functional, i would imagine it experiences every moment of it. i guess the big debate is whether it feels pain. i believe that any creature which has a sense of touch, feels pain. its just that people dont tend to even want to debate this as many find it impossible to sympathise with a non-mammal