I was part of a study in the late 80-.s in Tennessee . A group from Tennessee Tech took all the fish we caught in club tournaments put them back in an area that was boardered off from the rest of the lake. The fish had plenty of depth and room. During the summer months from July 1 until Sept 15 the secenario went like this, at weigh-in 2 % mortality, 24 hours 10% mortality, 72 hours 40% mortality. The hotter the water and the deeper the fish came from the higher the mortality. The longer they stayed in the livewell the greater the mortality.During the early spring and late fall early winter the loss was much less.
The bottom line was that once the water goes over 80 degrees, and the fish go deeper than 20 feet the mortality will be high. The more a fish is handled the greater its chance of dieing. If the fish are layed on the boats carpet or a dry belly board the greater the chance of thier dieing. We used catch and release formulas.
The results are that now that club only weighs 3 fish and they dont have any tournaments in July,August ro September.Fish2win