I will use my stupid as a example. Captured by 8 in mesh ( tangle ), custom boats, net pens to place tubes in, 500 gallon tanker oxygen & aerator equipped capable of holding 9 tubes. Loaded up 9 fish into the tubes to a net pen in the middle of the river and allowed them to stay for six hours. After transport when we dumped them from the tubes into the pond all 4 hens were dead. Tried twice more same results and stopped dead. It was Harry Senn that instantly knew the question and answer and it was stress so we went back to basics. The solution? We had to wait until the water temp dropped and the fish started move and problem mostly gone. It required fine tuning but we solved it. Harry described it as egg development under stress took the fishes clock way down and simply could not get themselves back to OK. The closest he could come to something human was how shock can kill a human. C&R is a tool not a silver bullet and to think it solves the question is more than a little reach. It can be successful and a total failure just depends on circumstance.