Pull one gill. If you pull a bunch the fish can die before it totally bleeds out.
For Dorado we use a screwdrive to the head, if you hit it at the correct angle the pinkish brain drool will come out, then it dies.... fast....
For Tuna we come from the front and hit soft spot on the head with the screw driver or needle nose. Kills'em quick.
We bleed all fish as well.
If your handling rockfish and don't want to get poked, use scissors to cut a gill.
Alot of the guys use these
They also cut spectra like butta...