Can Fish Experience Pain?

Abstract

Experiencing pain is one of the key drivers of deciding whether to protect an animal under legislation and guidelines. Over the last two decades empirical evidence for fish experiencing pain has grown and this chapter reviews the current state of our knowledge. Defining animal pain has been problematic but a definition based upon whether whole animal responses to pain differ from non-painful stimuli and whether the experience alters future behavioural decisions and motivation is adopted. Studies show that fish have a similar nociceptive system to mammals, that behaviour is adversely affected and that this is prevented by pain-relieving drugs demonstrating that fish respond to pain in a different manner to innocuous events. Further, fish are motivated to avoid areas where pain has been experienced and are consumed by the painful event such that they do not exhibit normal fear or antipredator responses. Taken together these results make a compelling case for pain in fish. However, this topic is still debated and the chapter discusses the opposing opinions. If we accept pain occurs in fish then the wider implications of the use of fish must be considered. It would be in the public’s interest to keep fish healthy for a myriad of reasons including disease-free fish production, preventing zoonoses, conservation and sustainability of fish stocks and valid experimental results from laboratory studies using fish models.