The Iki jimi spot is like a temple - there is a soft spot that is located just behind the eyes between the lateral line and the top of the head, it is pretty hard to miss, results are instant, then cut their throat and whack them in the slurry - you'll get the best quality fillets every time. Aparantely fish have an enzyme that caues the flesh to detiorate very quickly if not killed, bled out and chilled almost immediately. The only fish i don't bleed are whiting and flathead - I've never seen blood on the lateral line in those species. As for anything else, Iki Jimi spike it, bleed it out in the slurrey - the results are amazing
cheers
Rhys