I’ve seen many people trying to justify eating small fish (such as, salmon) by saying ”They can’t feel pain anyway” or ”They probably don’t have complex nervous systems or brains”. According to scientific evidence, these are myths.
WHAT SCIENCE SHOWS
YES – Fish Can Feel Pain
- Similar to humans, fish also have A-delta and C neuronal fibers involved in transmission of pain stimuli (Sneddon et al, 2003)
- Substance P, which is involved in pain transmission in mammals has been found in the hypothalamus and forebrain of finfish (Ashley, 2007)
- Fish hypothalamus and forebrain show changes in activity when pain stimuli are administered, indicating pain processing capability (Ashley, 2007)
- Salmon exhibit erratic swimming after CO2 gassing prior slaughter, indicating capacity to experience stress (Southgate and Wall, 2001)
”When experiencing a painful event, the human neo-cortex shows considerable activity and based on comparative anatomy, some scientists have gone to say that fish do not perceive pain or fear because they lack a neo-cortex (Rose, 2002). However, human brain activity is not exclusive to the neo-cortex when receiving a painful stimulus (Braithwaite, 2010). Underlying brain areas show changes in activity as well, as MRI studies show and salmon share some of these brain parts like the hypothalamus and forebrain. Thus, using the same logic as some proponents of the aquaculture industry, we can say that fish, including salmon, do have some brain parts necessary to process pain since some brain parts involved in pain perception are homologous to humans.
Furthermore, some argue that since fish have a short memory in the order of seconds, they would not remember any pain, even if they felt it, or would simply lack a complex brain enough to make perception out of something when they cannot form memories. However, juvenile salmon learn aspects of their environment when migrating to the sea and rely on this memory (that has lasted on the order of years) to return to the freshwater the came from to spawn (Sneddon et al, 2003). Thus salmon have more complex brains than some people thought and they are capable of forming memories. Thus, they might be able to remember a painful experience.
Based on the scientific evidence available, there is a strong indication that fish, including salmon, can feel pain.”