Applied Zoology: Animal welfare

As the global demand for fish rises and aquaculture expands rapidly, ensuring the welfare of fish during slaughter becomes increasingly imperative, given their susceptibility to pain and distress. Achieving humane slaughter entails either instant killing or rendering fish unconscious until their demise. However, distinguishing between dead, unconscious, or immobilized states during the slaughter process poses significant challenges. To address this issue, Dr. Jeroen Brijs and Prof. Thorsten Schwerte at the University of Innsbruck and Dr. Albin Gräns at the Swedish University of Agricultural Sciences are collaborating on an international effort. They aim to develop a portable, user-friendly method capable of real-time assessment of various stunning and slaughter techniques at aquaculture facilities. This innovative approach involves monitoring brain activity to determine if stunning or slaughter methods instantly renders fish dead or irreversibly unconscious. By providing insights into enhancing stunning and slaughter practices, this project endeavors to alleviate the suffering of countless individual fish.

Non-invasive technique for determining changes in the state of consciousness in fish. (A) The portable and robust field setup for evaluating the effectiveness of slaughter practices on-site at an aquaculture facility. (B) The custom-made cutaneous brain electrodes used to measure the electroencephalogram (EEG) of rainbow trout, which allows the detection of visually evoked responses (VERs) from a flashing stroboscope light. (C) A clear example of VERs present in the EEG of a conscious fish prior to stunning, as well as (D) the effects on the brain activity of a fish following an effective stun (green line, VERs absent, fish unconscious) and ineffective stun (red line, VERs present, fish conscious).