All fish that are caught for eating must be handled carefully to reduce stress and humanely killed as soon as possible after capture. Humane killing requires that the fish is stunned (rendered instantaneously insensible) before being bled out.
Fish should remain in water until immediately prior to stunning. There are two methods that can be used to stun fish caught by hand: percussive stunning and spiking (also known as pithing or iki-jime).
Percussive stunning involves a forceful and accurate blow to the head with a blunt instrument. The force required will depend on the size of the fish. The blow should be aimed just above the eyes to impact on the brain. The effectiveness of the stun should be checked and another blow applied if the fish is not unconscious.
Spiking involves driving a sharp spike (such as an ice pick or a sharpened screwdriver) into the brain of the fish. The spike should be placed in a position to penetrate the brain of the fish and then pushed quickly and firmly into the skull. The impact of the spike should produce immediate unconsciousness. The spike should then be moved from side to side to destroy the brain. Visit www.ikijime.com for a detailed description of this process.
After stunning or spiking, the fish should be bled out by cutting the gill rakers or, with larger fish, a main artery.
The following methods are not suitable for killing fish as they do not result in a rapid or humane death: chilling with ice in holding water, carbon dioxide in holding water; chilling with ice and carbon dioxide in holding water; salt or ammonia baths; asphyxiation by removal from water; bleeding out without stunning.