Fresh Studio has partnered with Can Tho University and Ace Aquatec to conduct research on the efficacy of a prototype in-water electric stunner on catfish (Pangasius hypophthalmus) in Vietnam.
The project aims to verify the parameters set by the in-water electric stunner's developers (Ace Aquatec) and the University of Stirling under lab conditions. The study focuses on the duration of the stun, recovery time of the animal, and stress levels experienced compared to traditional slaughter methods.
Background
Fish welfare is a relatively new concept in Southeast Asia, with Vietnam being no exception. Production and operational efficiency remain the top priorities, with welfare often sidelined unless it directly impacts output. Among the various welfare challenges faced by farmed fish, slaughter receives the least attention, largely because it occurs at the final stage of production and is often viewed as an area where additional care is an unnecessary cost. As a result, fish usually undergo highly stressful traditional slaughter methods such as live exsanguination and chilling.
Post stun monitoring
While fish welfare practices are slowly gaining traction in Vietnam, several challenges hinder progress. These include perceived costs, the investment required in new technologies, narrow profit margins, and prevailing cultural attitudes. A push for more humane fish farming has particularly come from European retailers, legislative frameworks and certification standards. Gaining access to these markets increasingly depends on meeting welfare standards. However, there is also developing local awareness and interest in how improving welfare can also improve quality.
In-water electric stunning is considered a more modern and humane euthanasia method, rendering fish unconscious before death, thereby reducing the potential for suffering. This is the primary method used in Europe and is gradually being adopted elsewhere. Some processors in
Vietnam has begun incorporating dry electric stunning into commercial slaughter, where fish are stunned via electrodes as they travel on a conveyor belt. While this represents a significant improvement over live exsanguination, it relies on correct fish position to prevent pre-shocks, and its settings may cause unnecessary suffering.
This project was initiated to assess whether in-water electric stunning is a more humane and consistent alternative to traditional methods.
Assessment of Stunning Methods
The research team, comprising of consultants from Fresh Studio, faculty from Can Tho University (CTU), and CTU students, assessed four treatments, using both traditional and in-water electric stunning methods.
The trial included two control treatments replicating “ideal” and “true” slaughter methods currently used in processors, and two in-water electric stunning treatments. These allowed the team to observe recovery and compare stress levels across groups.
Carying out post-stun assessments
Data collection methods included direct observation (via film and photography), cortisol sampling, surveys, and analysis of flesh quality. One electric stunning treatment was specifically observed and timed for signs of consciousness at each stage, with time stamps recorded.
Blood samples from each treatment group were tested for cortisol levels; used as a biological indicator of stress. Flesh coloration and structure were also analyzed to determine the impact of each method on product quality. Fillets were retained for future sensory analysis.
Next Steps
With data collection complete, Fresh Studio and the research team are now processing results to draw conclusions on the effectiveness and ethicality of in-water electric stunning.
The team is optimistic that the findings will encourage broader adoption of electric stunning among processors.
Next, Fresh Studio will host two workshops to share the trial results and promote humane slaughter practices. These sessions will be complemented by a stakeholder survey to gauge understanding of electric stunning and slaughter techniques.