In purse seine fisheries, captured salmon are scooped from the net alongside the boat and brought onboard to be sorted by the crew and any bycatch is released. Released fish will be exposed to air to some extent while on the deck which limits their ability to respirate, they will exhaust themselves trying to escape, and may also suffer external injuries during capture and handling. If these stressors can be minimized through better handling, their probability of survival will be increased. However, the human element of those sorting the fish is the determining factor in improving handling: How are these fish handled? How does handling influence survival probability? How can handling be improved?
Science Trends (5 Feb. 2019)