Thanks for the info on bleeding, I'm going to try that method.
Another one I've used, is to slip the knife into the gill slot, sharp side down and cut downwards, through the tip, of the triangle of the body as it meets the forward end of the gill plates, this cuts the vessels coming out of the heart and if not too far back, doesn't damage the heart, when rock fishing, I put the fish in a rock pool and the fish pumps all the blood out , replacing it with salt water and then dies. I guess on a Kayak I'd hang the fish on a stringer in the water and wait for sharks
