Scientific literature is divided, with multiple studies and reviews arguing that fish possess nociceptors and behavioral responses indicating they can feel pain, while dissenting researchers contend they lack the necessary neocortex for conscious pain experiences.
Recent developments in the study of pain in animals have demonstrated the potential for pain perception in a variety of wholly aquatic species such as molluscs, crustaceans and fish. This allows us to gain insight into how the ecological pressures and differential life history of living in a watery medium can yield novel data that inform the comparative physiology and evolution of pain. Nociception is the simple detection of potentially painful stimuli usually accompanied by a reflex withdrawal response, and nociceptors have been found in aquatic invertebrates such as the sea slug Aplysia. It would seem adaptive to have a warning system that allows animals to avoid life-threatening injury, yet debate does still continue over the capacity for non-mammalian species to experience the discomfort or suffering that is a key component of pain rather than a nociceptive reflex. Contemporary studies over the last 10 years have demonstrated that bony fish possess nociceptors that are similar to those in mammals; that they demonstrate pain-related changes in physiology and behaviour that are reduced by painkillers; that they exhibit higher brain activity when painfully stimulated; and that pain is more important than showing fear or anti-predator behaviour in bony fish. The neurophysiological basis of nociception or pain in fish is demonstrably similar to that in mammals. Pain perception in invertebrates is more controversial as they lack the vertebrate brain, yet recent research evidence confirms that there are behavioural changes in response to potentially painful events. This review will assess the field of pain perception in aquatic species, focusing on fish and selected invertebrate groups to interpret how research findings can inform our understanding of the physiology and evolution of pain. Further, if we accept these animals may be capable of experiencing the negative experience of pain, then the wider implications of human use of these animals should be considered.
Phenomenal consciousness or the subjective experience of feeling sensory stimuli is fundamental to human existence. Because of the ubiquity of their subjective experiences, humans seem to readily accept the anthropomorphic extension of these mental states to other animals. Humans will typically extrapolate feelings of pain to animals if they respond physiologically and behaviourally to noxious stimuli. The alternative view that fish instead respond to noxious stimuli reflexly and with a limited behavioural repertoire is defended within the context of our current understanding of the neuroanatomy and neurophysiology of mental states. Consequently, a set of fundamental properties of neural tissue necessary for feeling pain or experiencing affective states in vertebrates is proposed. While mammals and birds possess the prerequisite neural architecture for phenomenal consciousness, it is concluded that fish lack these essential characteristics and hence do not feel pain.
Pain perception and appropriate behavioral responses are important for survival. The conservation of the opioid ligand and receptor suggests evolution of opioid receptors mediating antinociception throughout vertebrate phylogeny. Fish, amphibians, and reptiles have appropriate neurologic components, display the appropriate behavior in response to a painful stimulus, and possess antinociceptive mechanisms to modulate pain. Because pain perception in these species is therefore likely to be analogous to that of mammals, invasive and painful procedures should always be accompanied by appropriate analgesia and anesthesia. Although specific doses have not been established in clinical trials, clinicians should attempt to provide lower vertebrates with appropriate analgesia during painful procedures. Further experimental and clinical investigations are necessary to expand the current veterinary literature in the area of pain and analgesia in lower vertebrates such as fish, amphibians, and reptiles.
would experience pain and suffering..." In 2015, Brown wrote "A review of the evidence for pain perception strongly suggests that fish experience pain in
Pain is an aversive sensation and feeling associated with actual, or potential, tissue damage. It is widely accepted by a broad spectrum of scientists and philosophers that non-human animals can perceive pain, including pain in amphibians.
Pain is a complex mental state, with a distinct perceptual quality but also associated with suffering, which is an emotional state. Because of this complexity,
All vertebrate species have a common brain archetype divided into the telencephalon and diencephalon (collectively referred to as forebrain), mesencephalon (midbrain) and rhombencephalon (hindbrain). Nervous connections to the telencephalon indicate that frogs may be able to perceive pain.
In 2002, James Rose, from the University of Wyoming, published reviews arguing that fish cannot feel pain because they lack a neocortex in the brain. If the presence of a large, considerably developed neocortex is required for experiencing pain, as Rose suggests, this theory would eliminate birds, amphibians, other non-mammalian animals, and even some mammals from having the capacity to experience pain. Other researchers do not believe that animal consciousness requires a neocortex, but can arise from homologous subcortical brain networks. Animal behaviouralist Temple Grandin argues that fish (and therefore, presumably, amphibians) could still have consciousness without a neocortex because "different species can use different brain structures and systems to handle the same functions."
Fish can be considered from two perspectives: instrumental and ethical. The instrumental approach views fish as economic resources to be exploited in fisheries and aquaculture, as well as vital elements of ecosystems that play a key role in maintaining biological balance. From this standpoint, fish possess instrumental value. The ethical perspective, by contrast, emphasizes the ability of fish to feel pain, recognizing them as sentient beings with moral status. The article examines neurobiological and behavioral evidence suggesting that fish have pain receptors (nociceptors), display protective responses to harmful stimuli, and learn to avoid painful situations – indicating a basic form of consciousness and the capacity for subjective experiences of pleasure and pain. The article also considers the arguments of skeptics, who contend that fish lack sufficiently developed brain structures, such as the neocortex, which are thought to be necessary for the conscious experience of pain. From this viewpoint, the behaviors exhibited by fish may be attributed to nociceptive reflexes rather than to a conscious experience of suffering.
The article is a sketch of the current state of knowledge about the aspect of the sentience and internal life of fish, which is still too rarely taken into account – about the construction of pain experiences, affective states and possible emotional experiences. In order to draw conclusions about the possibility of fish feeling emotions, firstly it is necessary to answer questions about simpler content that characterize the fish cognitive system: whether fish are able to create a special type of affective-physiological feeling, such as pain with distress, and whether fish have simple affective states – fear or anxiety – which are correlated with the experience of pain. The rudimentary nature of these issues results from the assumption that the simplest behavioral reactions and cognitive-affective sensations are considered a necessary condition for the ability to construct more complex cognitive structures, such as sensorimotor experiences, mental representations and emotional states. The ability to feel pain and the correlated ability to feel negative affects, such as fear or anxiety, can be considered indicators of a species' possession not only of physiological needs, but also of mental preferences. Thus, the ability to experience pain with fear and anxiety can be treated as a predictor of cognitive-behavioral flexibility and a certain degree of cognitive control in fish. A positive answer to the questions about feeling pain, fear or anxiety is a starting point for further
Key (2016) describes the neural system involved in human pain experience in an excellent fashion but then suggests that only that complete system can generate the experience of pain. Thus animals without all components will not feel pain. This argument has been refuted in the past by analogy to vision where it is clear that a broad range of taxa, vertebrate and invertebrate, have good visual abilities albeit with completely different central nervous systems and receptors. This known counterargument to Key’s main idea is not mentioned in the target article. Further criteria that might indicate pain and studies examining these criteria in fish and other animals also get scant attention. The function of pain in fitness terms is not considered, yet that might provide clues as to when and how often pain might have evolved.
Fish fulfill several criteria proposed as indicating that non-human animals experience pain. These fulfilled criteria include a suitable nervous system
Fish fulfill several criteria proposed as indicating that non-human animals experience pain. These fulfilled criteria include a suitable nervous system and sensory receptors, opioid receptors and reduced responses to noxious stimuli when given analgesics and local anaesthetics, physiological changes to noxious stimuli, displaying protective motor reactions, exhibiting avoidance learning and making
Fish fulfill several criteria proposed as indicating that non-human animals experience pain. These fulfilled criteria include a suitable nervous system and sensory receptors, opioid receptors and reduced responses to noxious stimuli when given analgesics and local anaesthetics, physiological changes to noxious stimuli, displaying…
While animal welfare is a growing global concern, there has been very little research into how it is understood in Iran. Cultural, religious, and legal factors influence attitudes and practices in ways not addressed by existing research. This study provides culturally grounded insights for improvement of animal welfare in Iran. Utilising a validated survey tool, we investigated the attitudes of Iranians toward the welfare of farmed, companion, and wild animals. A total of 325 responses were collected. The findings indicate that animal welfare is considered important to Iranians, with the majority expressing interest in improving the welfare practices. Despite varying degrees of familiarity with different animal species, there was a consensus on the importance of enacting laws to protect animal welfare. Most participants agreed that chickens feel pain (92.9%) and emotions (79%), whereas fewer attributed these capacities to fish, with 63.6% acknowledging pain and 59.5% acknowledging emotions. Furthermore, most of the participants agreed that animals should not endure pain in the slaughter process (97.8% agreement). While the majority of participants agreed that pre-slaughter stunning was better for the animals (78.7%), only 51.7% agreed that they would prefer to eat meat from animals that had been stunned; reflecting the traditionally held views regarding the role of stunning in Halal meat production. The results of the current study support previous findings suggesting that concern for animals may be a universal human inclination, although, in Iran, attitudes towards specific species and agricultural practices are also shaped by religious perspectives.
Introduction Xilt 1. Experience and Its Limits: The Problem 1 2. Experience and Consciousness 2 2.1. … that fish feel pain but not depression. Is the fish shown below feeling depressed? EXPERIENCE AND ITS LIMITS … acetic acid feel pain. 6.3 IS THERE A BETTER EXPLANATION? The hypothesis that fish experience pain offers