Im not sure I'd call it a death sentence...but the more wounding, the more handling, the more stress unhooking trebles or multiple trebles of a certainty will increase the fish mortality.
A single hook, or better yet single barbless in a pike can often be unhooked without even getting the fish out of the water...and because they are toothy...it also saves you $$$$ on Triple antibiotic ointment and bandaids!
