This is an important article. Especially if you are a sports fisherman.
phys.org

New study quantifies fish slaughter pain and cost-effectiveness of welfare solutions
A new study in Scientific Reports reveals the hidden pain of fish during slaughter and offers practical solutions to improve their welfare. Focusing on rainbow trout, the research quantifies pain in air asphyxia—a common slaughter method—using the innovative Welfare Footprint Framework (WFF)...