Ikejime (活け締め) or Ikijime (活き締め) is a method of paralyzing and bleeding fish to maintain its quality. The technique originated in Japan, but is now in widespread use. It involves the insertion of a spike quickly and directly into the hind brain, thereby causing immediate brain death. A fish brain is usually located slightly behind and above the eye. Websites such as www.ikijime.com show the brain location of many fish species. When spiked correctly, the fish fins flare and the fish relaxes, immediately ceasing all motion. Destroying the brain and the spinal cord of the fish will prevent reflex action from happening. Otherwise, the move of the muscle consumes Adenosine triphosphate (ATP) in the muscle and lactic acid is produced, thereby making the fish sour. On the other hand, if fish is killed in this technique, ATP in muscle remains and later changes into tasty amino acid. The blood contained in the fish flesh retracts to the gut cavity, which produces a better coloured and flavoured fillet. This method is considered the fastest and most humane method of killing fish.
Another technique described in APEC Air shipment of live and fresh fish and seafood guidelines is "a cut is made toward the front of the flatfish severing the major artery and the spinal cord. Placement of the cut is made to preserve the greatest amount of flatfish flesh. This paralyzes the flatfish. A second cut is made in the tail to hasten the removal of blood. Flatfish are then chilled slowly to maintain circulation and facilitate the bleeding process. After the flatfish have been bled, they are transferred to a salt/ice water slurry and chilled" to 12 °C.
Ikejime has been successfully used manually in the tuna and yellowtail industries, along with limited use in sport and gamefishing, and provides a rapid slaughter technique with concurrent quality benefits. Rather than cutting their throats and leaving them to die by bleeding, research indicates () it is better to use ikejime and put the fish straight into an ice slurry. Fish being exported to Japan and certain other markets should not be allowed to die naturally, but should be killed immediately after being brought on board by using ikejime method.
- "APEC AIR SHIPMENT OF LIVE AND FRESH FISH & SEAFOOD GUIDELINES". APEC Fisheries Working Group. January 1999. p. xxiii.
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