Interventions - vaccinations and treatments:

Although interventions are an integral part of safeguarding aquatic animal welfare, their welfare must also be monitored and protected during these practices as they can present significant risks/stress of their own. Antibiotics, bath treatments, and vaccinations can involve handling out of water, use of anaesthetics, and injections, all of which can cause severe stress if done poorly. Outside of vaccinations, it is also important to recognise the likelihood that these practices will be carried out on fish that have already had their health and welfare compromised (e.g., disease) and are even more vulnerable to additional stressors. 

The following video shows the vaccination of pangasius juveniles using a vaccination table and syringe guns which deliver a precise micro-dose of vaccine to each fish injected. The fish are anaesthetised prior to this procedure. 

This video shows the manual vaccination of pangasisus juveniles. Whilst watching, try to identify the welfare risks, how they are being managed, and what further steps you think could be taken to ensure best welfare practices. Note there is no audio for this video. (download text decription of video content)

The following video showcases an automated vaccination process now commonly implemented in the salmon farming industry.

NB: This third-party video is linked for illustration only and copyright and control belong entirely to the originating organisation

Slaughter:

From a welfare point of view, some of the most important factors in slaughter are instead the methods of handling during transfer and leading up to the point of stunning and killing; these points have been covered in the previous section ‘handling practices’. Poor methods of the slaughter process itself can also severely compromise welfare, causing significant pain, fear, stress, exhaustion, and starvation. This section focuses specifically on the methods involved in the stunning and killing of the animal.

Factors influencing welfare at this important stage are also numerous. Ideally, the animal is first rendered unconscious (the brain is unable to process sensory inputs) and insensible (unable to perceive or respond to stimuli) by some form of stunning to avoid pain, fear, or distress that lasts up until point of death. Sedation with anaesthetics prior to slaughter may reduce stress associated with the event. The method of stunning involved, and how effective / reliable it is at achieving the above goal, is therefore an essential aspect for their welfare. Some of the methods involved are described below:

Some of the methods described above involve both stunning and killing processes. An overview specifically of methods used for killing without stunning are next described:

Relevant to the other handling practices previously outlined, and arguably even more important here, staff training is essential for ensuring stunning and killing is conducted effectively. 

The following video shows some examples of the harvesting of fish and shrimp, involving the use of ice.

This video shows some examples of harvesting shrimp from ponds and fish from cages. For each example shown, identify the welfare risks, how they are being managed, and what further steps you think could be taken to ensure best welfare practices. Note there is no audio for this video. (download text description of video content)

The following video from Regal Springs showcases their implementation of in-water electrical stunning of tilapia.

NB: This third-party video is linked for illustration only and copyright and control belong entirely to the originating organisation