This research shows that the heart rate of a fish reaches its maximum after only a short period (1 minute for largmouth bass) of angling.
Time out of the water, after capture, also adds to the stress and recovery period. Health is affected afterwards, and the fish may not be able to reproduce properly. In some cases, it will be impossible for the fish to recover at all, and death may result.
"The intensity of the cardiac response did not increase with angling duration, indicating that the cardiac response is maximized even with brief angling duration. As a result, more severe angling stress is not counterbalanced by a greater cardiac response, but rather by requiring a longer recovery period."
"Our results also suggest that air exposure, especially following exhaustive exercise, places an additional stress on fish that increases the time needed for recovery and likely the probability of death."
"The repeated handling of fish during tournament angling, including culling, the addition of fish or other live-well disturbances, and the final tournament weigh-in, which adds an additional several minutes of air exposure, further adds to already heightened stress levels."
"When these cumulative stressors do not result in death, the resultant energetic disruptions clearly have negative impacts not only on the short term health and condition of the fish, but also most likely on its biological fitness, i.e. its lifetime reproductive success."