There has historically been almost no effort made to reduce the inhumaneness of fish slaughter. The majority of fish are killed without stunning, by asphyxiation either in the air or on the ice. One study found that it takes common species of fish 55-250 minutes to die via asphyxiation. Fish that aren’t asphyxiated often die by being live gutted; the same study found that live gutting can take up to 25-65 minutes to kill the fish. Fish who are stunned are typically struck on the head (percussive stunning), stunned electrically, or stunned using gas. Pre-slaughter stunning is more common in wealthier nations (like the UK, Northern Europe, Chile, Canada, and Australia) and for high-value species (like salmon and trout).