In this field study in Lake Erie, the effects of catch-and-release angling on rock bass were observed.
The scientists found that after the fish were removed from the water, their heart beat went up severely. After just 30 seconds, the fish took 2 hours to recover. Worse still, when they were taken out for 3 minutes, it took a full 4 hours for them to recover.
"Fish experienced severe bradycardia during air exposure, but after being returned to the water, all fish exhibited elevated cardiac output. Fish exposed to 30s of air exposure required 2h for full recovery, whereas those exposed to 180s of air required 4h."