Salmon farming - welfare at the time of killing: guidance
This guidance applies to Scotland only and is issued by the Scottish Ministers under section 38 of the Animal Health and Welfare (Scotland) Act 2006. It relates to the welfare of farmed fish at the time of slaughter or killing.
Annex A
Methods and parameters for the killing of farmed salmon, cleanerfish cohabiting with salmon, and incidentally caught species within the farm pen
1. Penetrative Captive Bolt Device
Description
Severe and irreversible damage of the brain provoked by the shock and penetration of a hollow punch or spike.
To be used for
Slaughter, depopulation and other situations
Key parameters
Position of the blow, Appropriate velocity, exit length and diameter of bolt.
Maximum stun to stick time
Specific Requirements
Accurate positioning of the device is required if injury and suffering is to be avoided
2. Percussive blow to the head
Description
Severe and irreversible damage of the brain provoked by a percussive blow to the head (may produce a stun or instantaneous kill depending on force) delivered by a non-penetrating mechanical device or handheld priest
To be used for
Slaughter, depopulation and other situations
Key parameters
Position and direction of the blow.
Appropriate mass and velocity of the non-penetrating bolt according to fish size and species.
Specific Requirements
Accurate positioning and adjustment of automated equipment is required if injury and suffering is to be avoided
3. Electrical Stunning Out of Water
Description
Exposure of the brain or entire body to a current outside the water resulting in an immediate loss of consciousness.
To be used for
Slaughter, depopulation and other situations
Key parameters
Minimum current (A or mA).
Minimum voltage (V).
Maximum frequency (Hz).
Minimum time of exposure.
Frequency of calibration of the equipment.
Optimisation of the current flow.
Prevention of electrical shocks before stunning.
Position and contact surface area of electrodes.
Maximum time between water exit and stun application.
Specific Requirements
The stun should be immediately followed by bleeding or percussive stunning if recovery is to be avoided unless suitable electrical/time parameters are used to kill the fish.
Electrical parameters for fish of the size and species for which it is used must have been demonstrated to reliably render them unconscious based on scientific evidence. Ideally this would include EEG evidence using the best available protocols as scientific knowledge on these develops.
4. Electrical Stunning in Water
Description
Exposure of the entire body causing immediate loss of consciousness
To be used for
Slaughter, depopulation and other situations
Key parameters
Electric field (e.g. V/cm)
Water conductivity
Maximum frequency (Hz).
Minimum time of exposure.
Field orientation
Frequency of calibration of the equipment.
Prevention of electrical shocks before stunning.
Position and contact surface area of electrodes.
May be a stunning or a killing method with different parameters as appropriate. These should be specified in the user manual.
Specific Requirements
The stun should be immediately followed by bleeding or percussive stunning if recovery is to be avoided, unless suitable electrical/time parameters are used to kill the fish.
Electrical stunning of fish in water must take into account the conductivity of the water, where fresh water conductivity may vary from 20 – 1,000 µS/cm and seawater ≤50,000 µS/cm, which will influence the strength of the electric field and consequently the efficacy of the stun
Electrical parameters for fish of the size and species for which it is used must have been demonstrated to reliably render them unconscious based on scientific evidence. Ideally this would include EEG evidence using the best available protocols as scientific knowledge on these develops.
5. Overdose of anaesthetic
Description
Placing in an anaesthetic solution authorised for use in fish, causing loss of consciousness and death over a period of time.
To be used for
Killing other than for human consumption.
Key parameters
Dosage, exposure time, size and weight of fish, water temperature and other relevant factors to ensure a suitable transition to lasting unconsciousness and an effective kill.
Specific Requirements
Subject to veterinary advice and prescription for the anaesthetic to be used. The concentration of anaesthetic used should not be aversive.
Contact
Email: animal.health@gov.scot