I have to say that I think they are very tough. Out of the 300 bg I caught with a hook and stocked my pond with, none died from being caught and handled. How do I know? They stayed in a very overcrowded 30gallon tank for a few days after they were caught before being transported to my pond. You could see the little place in their lip where they had been caught but they were fine and would feed like pigs one day after being put in the 30 gallon. I think hooking the gills or real deep is about the only time they will die IMHO.