stress is more of a factor of a dead fish. Fish will usually die because of multiple factors, not just one ie exhaustion. Keep a fish in warm shallow water after a long battle sure it may die, but if you release and get it back to cooler o2 rich waters, it will be fine.
go over the stress threshold it will die. exhaustion is not enough of a stress to kill a healthy fish.
i know its a dragon flies, but I have seen this applied to fish in a aquaculture.