The question of whether fish can feel pain has been the subject of much scientific discussion in recent years. While fish have traditionally been considered to have insufficiently complex nervous systems to perceive pain, a growing body of research suggests that they may possess pain perception abilities similar to those of humans. This issue not only concerns animal welfare but also raises ethical concerns related to fishing, aquaculture, and the aquaculture industry in our daily lives.
The nervous system and pain perception in fish
Fish have nervous systems similar to those of mammals, possessing neural pathways for sensing external stimuli. However, the brains and neural networks of fish differ from those of mammals, leading many to believe that fish brains are simpler and incapable of feeling pain. But recent research has increasingly shown that fish are not devoid of pain perception.
First, while fish brains are indeed simpler than mammalian brains, they also possess neural receptors for pain perception. Research has found that fish have a receptor called TRPV1, which plays a crucial role in pain transmission in humans and other mammals (Sneddon, 2003). This receptor helps fish respond to noxious stimuli, suggesting that they may be able to feel pain.
Scientific research supports the ability of fish to sense pain.
Numerous experiments and studies have demonstrated that fish can sense and respond to pain. For example, a 2013 study showed that channel catfish (a type of fish) exhibit anxiety and stress responses when exposed to unpleasant stimuli (Chandroo et al., 2004). Researchers used hot water or injections to stimulate the fish, and the results showed that the fish exhibited behavior of avoiding the stimulus after injury, indicating that they can engage in a degree of "escape" behavior after pain occurs, similar to other animals with pain sensation.
Furthermore, another study in 2019 showed that fish release stress hormones after experiencing adverse stimuli, further proving that they can sense pain. Even fish in aquaculture environments exhibit avoidance behaviors to stimuli such as temperature changes and electric shocks, which are consistent with the criteria for animals to sense pain (Berni et al., 2019).
Fish's sense of pain and human ethics
Given that fish may be capable of feeling pain, this discovery has sparked widespread ethical concerns. An increasing number of countries and regions are revising their animal welfare laws to require more humane methods in fishing and aquaculture. For example, some countries have begun requiring fishermen to use anesthesia during fishing to reduce fish suffering. Meanwhile, the aquaculture industry is also considering how to optimize fish rearing environments to minimize discomfort and stress.
How can we protect the well-being of fish?
To ensure fish welfare, scientists and animal protection organizations have offered several reasonable suggestions. First, fishing methods should be improved to avoid using tools that could cause excessive suffering to fish. Second, improving the aquaculture environment, such as providing ample space, suitable water temperature and quality, can effectively reduce stress in fish. Furthermore, considering fish's pain perception, more humane methods of anesthesia and euthanasia could be developed in the future to reduce unnecessary harm.
Conclusion
In conclusion, mounting scientific evidence suggests that fish may possess the ability to sense pain. Although the brain structure of fish differs significantly from that of humans, their nervous systems still possess mechanisms for pain transmission. Therefore, adopting more humane practices in fishing and aquaculture to ensure the well-being of fish has become an important issue in global animal protection and the fisheries industry.
Further research and policy improvements will allow us to better understand the pain system of fish and take more effective measures to reduce their suffering during fishing and aquaculture. This is not only ethically sound but also contributes to the sustainable development of the global aquaculture industry.
References
Sneddon, LU (2003). The evidence for pain in fish: The use of behavior, physiology and neuroanatomy. Applied Animal Behavior Science, 82(4), 151-167.
Chandroo, KP, Duncan, IJH, & Moccia, RD (2004). Can fish suffer? Perspectives on sentience, pain, fear and stress. Applied Animal Behavior Science, 86(3-4), 225-250.
Berni, A., Ugalde, M., & Gómez, R. (2019). Stress in farmed fish and its effects on behavior and physiology. Aquaculture Research, 50(5), 1250-1263.
