Purse seine fishing for tuna captures hundreds of millions of fish in enormous nets, causing significant welfare harms during capture and death.
Tuna hauled in purse seines experience extreme crowding stress during the closing of the net, physical injury from contact with the net and other fish, and prolonged death by asphyxiation or crushing as they are pumped out of water. Given evidence of fish pain and consciousness, this represents significant suffering at massive scale. Bycatch of dolphins and sea turtles adds further welfare harm.