SalMar uses percussion stunners to anaesthetize the fish. This is an automatic system where the fish swims naturally into the stunning unit and gets knocked in the head so that they become unconscious. The operability of the automatic stunning units must be checked, evaluated and documented continuously throughout the workday. An exception is Vikenco, who use electrical stunning, which is an alternative anaesthetic method to percussion stunning.
After the automatic system, there is a manual control unit where SalMar operators check the consciousness of the fish, and if needed re-stuns the fish. Then, the operators cut the gills on one side of the fish using a sharp knife. The fish will bleed dry and die from the blood loss without regaining consciousness. This is widely considered the most humane method of fish killing.
All operators working with stunning and killing must have gone through a fish welfare training program by a licenced veterinarian or someone with similar knowledge of fish welfare and fish health. The training program must be approved by the local Food Safety Authority. SalMar also performs humane killing of cleaner fish and by-catch in accordance with local legislations.