Trout is one of the most widely farmed fish globally, and slaughter welfare has improved significantly in progressive operations but remains inconsistent across the industry.
Trout slaughter welfare has become a focus of aquaculture welfare science because these fish are farmed in large numbers and the range of slaughter methods in use varies enormously in their welfare implications. Percussion stunning, which renders fish unconscious immediately through a blow to the head, followed by immediate spiking of the brain, is the method most consistent with good welfare. Carbon dioxide stunning — widely used because of its low cost and ease of application — causes considerable distress as fish avoid the gas before losing consciousness, and is increasingly discouraged by welfare certification schemes. The economic barriers to better slaughter methods have decreased as equipment costs have fallen, and regulatory requirements or retailer standards are the most effective mechanisms for driving industry-wide improvement.