5 Pain, Sentience, and Animal Welfare
Learning Objectives
- Describe the nervous system components involved in the perception of pain in fish.
- Apply criteria for pain to assess whether an animal perceives pain.
- Describe different criteria used to judge sentience.
- Create and critique ethical arguments for the treatment of fish.
- Judge conditions that are most likely to cause fish pain and suffering and actions to alleviate pain and suffering.
- Distinguish between three alternative views on animal welfare.
In fact, fish are socially complex, with highly developed learning abilities (Brown 2015). Fish feel pain and suffer as a consequence, and we must carefully examine welfare, use, and fishing practices. Scientists have questioned the outdated perspective that fish cannot have consciousness as their brain morphology is too simple and lacks the cerebral cortex present in humans. Yet, denial of fish pain perception prevails despite many recent, fascinating discoveries that demonstrate that fish do experience and remember exposures to noxious stimuli in a fashion that is far more complex than mere reflex. Consequently, there are many lively discussions on how we should treat fish.
Think of all the ways that you use fish in your life. Perhaps you enjoy sportfishing or keep tropical fish in aquariums. Maybe you harvest live fish for bait fishing. You may prefer to purchase fresh fish from the local seafood market. You may enjoy watching fish in public aquariums or by SCUBA diving. Or perhaps you identify with Santiago, the aging fisherman in The Old Man and the Sea, who struggles to reel in a giant marlin. Humans use fish for sport, food, pets, business, education, scientific research, and many other purposes (Olden et al. 2020). Whenever we use fish for any reason, we need to ask certain questions: How might our actions influence fish? Do fish feel pain? Do fish suffer? Are fish aware of their actions? Do fish in captivity have what they want? Is the fish healthy? How can we balance fish welfare with the benefits humans get from fish?
Although anglers and others have long pondered these questions, scientists began systematic investigations of these questions only within the last 50 years (Vettese et al. 2020). According to the International Association for the Study of Pain, pain is “An unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage” (Raja et al. 2020). What causes “unpleasant” and “emotional” responses in fish is a difficult scientific question to answer, long neglected by researchers. Early laws that regulated how animals are used in experiments excluded cold-blooded animals. The Health Research Extension Act of 1985 (PL 99-158, 1985) and the Animals (Scientific Procedures) Act (1986) gave protections to fish and further stimulated the science of animal suffering to include fish (Dawkins 2008; Braithwaite 2010). After the first study investigating whether fis