Slaughter is the process of killing fish after harvesting. Numerous methods are used to slaughter fish, but most have been found to be inadequate and inhumane. Methods such as asphyxiation in air, carbon-dioxide stunning, gill-cutting (exsanguination), and live chilling are now recognised to be inhumane and as such should not be used. 

Acceptable slaughter methods should render the animal insensible without causing avoidable pain or suffering. According to the World Organisation for Animal Health (OIE) and the European Food Safety Authority (EFSA), percussive stunning and electrical stunning systems are best able to provide humane slaughter. However, the process of getting the fish to these systems can be counterproductive and raises questions around these techniques also. In order to get the fish to these slaughter systems, they are often extensively crowded and, in some cases, exposed to air. Crowding and air exposure are known to result in a significant panic and stress response in individuals.

The use of AQUI-S^® prior to stunning offers advantages for fish welfare and maximises the quality of the product following slaughter. 

Commercial Slaughter Methods

Iki Jime

Iki Jime is a traditional Japanese technique used to kill fish by brain ablation and render the fish immediately brain dead. A high degree of accuracy is needed for Iki Jime to be humane and effective. To ensure that Iki Jime kills humanely, the fish should be bled immediately. Learn more about the Iki Jime technique and the AQUI-S^® Iki Jime tool here.

   
Welfare score: 7/10 – This method should only be done by skilled operators.

Percussive Stunning

Percussive stunning involves a blow to the head. This requires a high degree of accuracy and enough force to render the animal instantly insensible. The fish should be bled immediately following stunning, to ensure death occurs while the animal is unconscious. Percussive stunning can be administered manually using a priest, or by an automatic stunning system. Automatic stunners are the more reliable and accurate method.

Electrical Stunning

Electric stunning involves passing an electric current through the brain, resulting in immediate unconsciousness. Done correctly, electrical stunning can cause humane death. The fish must be bled immediately following stunning.
Electrical stunning systems have been developed for commercial harvests. These include systems which stun fish while they are in the water, and other “dry” systems in which the electrodes make direct contact with the fish. The electrical current and conductivity of the water must be considered, as required conditions can vary significantly between species. If the current is incorrect, the fish may be paralysed but still sensible to suffering, or the carcass may be damaged by haemorrhaging and spinal injuries.

How Can We Improve Slaughter Welfare?

The use of AQUI-S^® immediately prior to stunning and slaughter, regardless of the slaughter method, reduces the stress and significantly improves the final flesh quality. Learn more about the Rested Harvest application and associated Quality Improvements.