Debating Fish Pain

In “The Great Fish Pain Debate” (Issues, Summer 2010), Troy Vettese, Becca Franks, and Jennifer Jacquet rightly state that in Germany the assumption that fish feel pain resulted in court cases and fishing-related legislation from the 1980s onward. The initial focus was on fishing competitions, which were ruled as unjustifiable because their primary motive was competition and not food. The Bad Oeynhausen case of 2001 on catch-and-release was the last in a long string of cases that dealt with keep nets, put-and-take fishing, and live baitfish.

However, the case did not have the importance Vettese et al. attribute to it. Importantly, public surveys published in 2014 show that the majority of the German public has no ethical problem with catch-and-release. In contradiction to what the article’s authors imply, catch-and-release continues to be allowed if there is a good reason for it, and competitive fishing events continue to exist whenever an acceptable goal is served, such as to improve water quality by harvesting overabundant cyprinids (a family of freshwater fish that includes carp).

The authors suggest that animal rights activists brought about significant changes in German fishing laws to account for fish welfare. However, the key transformative figure was Hermann Drossé, a public attorney and leading figure in the West German umbrella recreational fishing organization. That is, the most significant changes in relation to fish welfare in fishing legislation and practice were brought about by angler associations, not by animal rights activists.

Vettese et al. imply I have conflicts of interest. As is natural for a transdisciplinary scientist at the interface of science and society, I maintain productive relationships with many people and organizations that are involved in angling, conservation, and fisheries management. Some of these people or organizations have provided in-kind support for distributing surveys or were key information sources, and as such are acknowledged in my papers. These relationships do not affect my position as an honest knowledge broker. Implying I am bought by advocacy groups is absurd.

Vettese et al. claim that I call for “angling-friendly research” and that the code of practice of recreational fishing that I led as author “allows for the practice of catch-and-release, especially when participating in sport fishing competitions.” Both allegations misinterpret my writing. My work on fish pain and the ethics of angling has three objectives.

The first is to provide a fresh perspective on the evidence for fish pain. This is a natural scientific approach that has no predetermined goal beyond applying organized scepticism, which is a norm of science. The second is the analysis of the various ways by which anglers may impact the welfare of fishes and to suggest ways how to minimize such impacts. As mentioned, some of this work is critical of angling and certain angling practices. The third is the academic analysis of the implications of various animal and nature-related perspectives common to environmental ethics. Again, this writing is analytical rather than normative.

The authors suggest that I am of the opinion that fish do not feel pain. This is not what I am saying. Instead, I continue to emphasize the uncertainty of the question. For example, our review led by James Rose in 2014 concluded that “fishes are unlikely to experience pain.” I do not know how a fish feels, not the least because I am human.

Vettese et al. associate me with a racial ideology when they write that “much of the scientific research relevant to the debate over fish pain has built on foundations of bad evolutionary theory and poorly reasoned assumptions about brain function informed by the racial pseudoscience of Apartheid South Africa.” I take offense at the implication that anyone who is sceptical about fish pain is a racist.

Robert Arlinghaus

In the scientific realm, debate and discourse are the norm. At the end of the day, evidence almost always trumps emotion. But when it comes to the fish pain debate, emotion seems to win out every time. The article by Troy Vettese, Becca Franks, and Jennifer Jacquet is yet another such example.

I will start by stating clearly that I don’t know if fish have the capacity to feel pain. I consider myself a fish pain skeptic, but a fish welfare advocate. It all comes down to evidence. Evidence comes in many forms and with different levels of bias, rigor, quality, and relevance. When we ignore anecdotes and focus on the science, it is apparent that there are inherent issues within the studies that purport that fish feel pain, summarized in several comprehensive reviews. Yet special interest groups and the media focus on the headline of the day, with media outlets flip-flopping their headlines depending on what the latest empirical paper concludes (which is almost always one of two extremes: they definitely do or they certainly do not).

The musings by Vettese et al. are just that—another subjective essay on fish pain that fails to embrace the critical honest-broker lens that we should demand in an outlet such as Issues. What we so desperately need is to bring together all relevant experts and all available evidence and use contemporary evidence synthesis techniques (e.g., systematic review and meta-analysis) to address this question in a formal way. As a community (including both extremes in the debate) we have not had the courage (or independent funding) to do this.

I appreciate the history lesson the authors provided, but unfortunately it did not stop in the past and instead catapulted forward into the present and examined potential policy implications. I submit that the core issue with the fish pain debate is the quality of available evidence, not historical accounts of how the current state of affairs came to be. Vettese et al. dismiss evidence as being about politicizing science. In the COVID world we have seen how failure to use evidence in an objective manner has led to much suffering, and that should be a lesson to all that evidence should be the foundation for policy decisions regarding topics that influence humans and animals.

The authors conclude their article by stating: “A good life is more than freedom from pain, but somehow in the fish pain debate that came to be forgotten.” Ironically, the angling community is among the biggest advocates for fish and fish habitat conservation and restoration—but that is too often forgotten. If there are no fish, then the fish pain debate is entirely irrelevant. It is time to focus on the future and work toward fish welfare.

Steven J. Cooke

In their article, Troy Vettese, Becca Franks, and Jennifer Jacquet misinterpreted several authors, including us. They quote one of us (Derbyshire) as stating that the “entire case against fish pain rests on whether it is accepted that the fish nervous system is inadequate to generate pain,” which obscures that Derbyshire was (gently) critiquing an article by another researcher, Brian Key, that Derbyshire viewed as resting too heavily on neuroscience to dismiss fish pain. We feel this distorted the context of Derbyshire’s position, which is that although the neuroscience is important, we must also grapple with what we mean by pain in order to assess whether a fish, or anything else, feels pain.

Similarly, the authors accuse one of us (Rose) of “advancing the position that Smith had laid out decades earlier,” which is “that fish lacked a neocortex and therefore consciousness.” That statement misinterprets Rose, whose published accounts of the neural basis of human pain have repeatedly explained that it depends on spinal and subcortical components as well as cortex. Rose’s emphasis on neocortical function for pain is based on modern research in comparative neuroscience. Vettese et al. chose to tie this focus to the South African ichthyologist J. B. L. Smith and associate questioning fish pain with racial ideology.

The authors oversimplify complex discussion to fit their simplistic narrative that the fish pain debate has somehow served the interests of anglers. For example, they describe the fish A-delta and C-fibers identified by Lynne Sneddon as involved in transmitting pain, when the proper term to have used is nociception, which is the neural processing of noxious stimuli without subjective experience—that is, without feeling. The authors also ignore that the fish nociceptive afferents consist of extremely few C-fibers, which are the most abundant nociceptor in humans and responsible for provoking, through higher brain operations, severe pain.

In addition, Vettese et al. ignore the fact that injections of bee venom or acid into fish jaws are complex manipulations, very unlike fish hooks. Studies by Steven Cooke and others found relatively little effect on fish behavior following hooking, which undermines Sneddon’s claims and attendant hostility toward angling. These studies and findings were not considered by the authors.

We highlight the difficulty of projecting the pain experience of humans onto beings lacking the advanced self-reflective ability of humans. That should not be misconstrued nor portrayed as an argument for an “evolutionary break in consciousness.” Rather, it reflects the reality that consciousness requires a certain development of the nervous system, and any putative conscious experience will vary across different species.

We can draw useful distinctions between the fully self-reflective knowledge of being in pain, versus a simpler state of being in pain, versus an even simpler state of unconscious nociception. The researchers Antonio Damasio and Hanna Damasio have speculated that human pain might not depend entirely on the cerebral cortex, but they did so within the context of discussing “some grade of experience” that might be supported subcortically. We bring up all this because such nuanced discussions and interweaving of scientific findings with credible interpretations are sadly absent from Vettese et al.

Stuart W. G. Derbyshire

James D. Rose

Troy Vettese, Becca Franks, and Jennifer Jacquet’s core premise is that the debate over whether fish can feel pain “can be understood only by a return to the origin of the debate and its links to the recreational fishing sector.” We disagree.

In many countries, only taxa classified as sentient—that is, able to experience pain and to suffer—are covered by the legal regulations governing how humans interact with them. That is, their overall welfare, and in the case of laboratory or farm animals, how they are euthanized or slaughtered, is regulated and must conform to prescribed standards. Thus, research on aquatic animal welfare that is intended to inform the process that decides which taxa are regulated must provide evidence for or against the existence of sentience-pain-suffering.

When humans take sentient animals into their care (e.g, in the lab, on farms) we must provide them with comfortable conditions that optimize their health and welfare, and euthanize or slaughter them as quickly and painlessly as possible. Before slaughter, the animal must be rendered unconscious and insensible, eliminating the possibility for pain, distress, or suffering during the process. The conditions in which animals that are not sentient are kept, and the methods and duration of the euthanasia or slaughter process, are less critical, and less clearly prescribed, since they cannot (by definition) experience pain or suffer.

The preceding contextualizes the main driver for, and importance of, determining whether fish and other aquatic animals are sentient and have the capacity to experience pain and to suffer. Clearly, it is also a strong motivator for research on these questions and, very importantly, for the terminology used to describe the outcomes and conclusions of that research (i.e., pain vs. nociception; in nonsentient organisms, the latter does not result in a subjective experience of pain). In this context, using the word pain instead of nociception serves to obscure the uncertainty that exists in the science conducted to determine whether fish and other aquatic organisms are sentient and, thereby, experience pain and suffer. It also has sweeping implications, as it implies that all forms of human interaction with fish—and any other aquatic organism with which the word pain is associated—should be more broadly regulated.

When these realities are considered, it becomes clear that the answer to Vettese, Franks, and Jacquet’s question—how and why did fish pain come to be a contentious scientific question in the first place?—is not “recreational fishing.” What is also clear is that deciding whether fish and other aquatic organisms are sentient and can feel pain is a “wicked” problem, the answer to which—if it is even possible to obtain an unequivocal answer—has consequences that go far beyond recreational fishing. That is why there is such intense focus, from scientists and advocacy groups, on The Great Fish Pain Debate.

Howard I. Browman

Anne Berit Skiftesvik

Troy Vettese, Becca Franks, and Jennifer Jacquet’s interesting historical review of the ongoing controversy surrounding the question of pain in fish is very valuable. However, there are some inaccuracies that must be corrected and ideas that need clarification.

First, funding for the original study in which I was involved was awarded to Michael Gentle commencing in 1999, and he worked at the Roslin Institute, not Edinburgh University as the authors stated. I was employed by Gentle at the institute as a postdoctoral researcher. Gentle was a neurobiologist and expert electrophysiologist, and was internationally recognized for his work on pain in birds, with his forte in the laboratory recording from neurons. When I joined his lab there were no pilot data on fish—indeed, the Roslin Institute had never kept fish—so I started the project from scratch, building an aquarium and conducting and optimizing the neuroanatomical and electrophysiological techniques there, not at Edinburgh University. Gentle would always say “you don’t buy a dog and bark yourself,” which meant he expected me to lead and conduct the work.

Victoria Braithwaite was indeed Gentle’s collaborator and provided aquarium resources for the behavioral aspects that had to be set up, and I conducted the two published behavioral experiments at Edinburgh University. Results of the first experiment, published in 2003, were from the original grant proposal. However, the second planned experiment would not work, so Gentle and I designed the novel object test with Braithwaite’s input and resources. Gentle was an excellent mentor, providing incredibly pragmatic advice on all the work, and without his knowledge and support the project would not have happened.

Second, I was not aware of the historical background on pain in fish prior to 1999, and the authors’ account was the first I had read about this fascinating piece of history, so this information could not have influenced my thinking. I presume the authors’ statement that “debate over fish pain has built on foundations of bad evolutionary theory and poorly reasoned assumptions about brain function” must be aimed at the skeptics who propose that only organisms with a multilayered neocortex can experience pain—that is, only primates and humans. I have always stated that this notion is flawed, and that it defies the laws of evolution to suggest a function or trait suddenly arises in one animal group without any precursor.

Further, along with fishes, the bird brain has a singly laminated cortex, yet skeptics did not deny birds the capacity for pain until Brian Key’s opinion was published; Key stated that, yes, birds do experience pain, but similar evidence in fish is not acceptable. This opinion was heavily criticized by other neurobiologists as flawed thinking. Of course, laboratories across the world are now confirming the early scientific findings and providing convincing evidence for pain in fish.

Finally, the authors do pain a disservice by suggesting it is limited in its scope. The research on fish pain has been the driving force in substantial improvements in fish welfare legislation and guidelines, and has informed public opinion. Much of my work and that of others has had significant impact in the way fish are treated. Without evidence of pain and suffering, policy-makers and legislators will not take action to protect a given species. Of course, I agree that we should know more about positive welfare and how to enhance the way we treat fish to improve their lives. This would be beneficial to us in terms of biodiversity, conservation, and sustainability of populations; economic return in aquaculture from healthy fish; valid results from studies of laboratory fish; and good welfare of companion and ornamental fish in public aquaria.

Lynne U. Sneddon

Troy Vettese, Becca Franks, and Jennifer Jacquet provide a very nice review of the history of the fish pain debate. It’s easy to see that it was initially driven by animal welfare versus anglers. I often liken the debate to big tobacco or climate change denialists versus the people.

In all these cases, each side wheels out its scientific champions for the cause. The denialist cause may be to throw just enough doubt on the argument to confuse the masses. But I suggest the similarities are greater than they first appear. Although not many fish are killed by anglers relative to commercial fishing operations, make no mistake that recreational angling is big business. So big, that in many countries, including Australia where I live, the state and federal governments actively encourage angling. It’s not about anglers’ rights any more, but thoroughly about big business versus animal welfare. Those that deny fish pain are unashamedly backed by the angling industry.

Where is the science of sentience at? Let me state upfront that we cannot solve the “other minds” problem directly. You have no idea what another person is thinking or feeling. Even if they describe it to you, you must imagine it. That is true for other animals as much as it is for other humans. We simply can’t go any further in that debate. What animal welfare scientists do is look for the cognitive traits and behavioral signs that indicate that animals are sentient in the same way we do for human children. We also examine the neurophysiology that underlies those traits.

Pain is just one of many subjective states (feelings) that are common to all vertebrates. Darwin pointed out how important feelings are for driving animal behavior. Positive feelings reinforce behavior, negative feelings suppress behavior. There is good reason to suppose that natural selection acts on feelings as much as on any trait that is important for survival. So this fish pain debate is not just about pain; it’s about fear, anxiety, hunger, happiness.

The central point that the fish pain deniers make is that humans feel emotional, subjective pain because they have a cortex. But this faces several problems. First, there is huge debate about whether that is even true. Most neuroscientists think it’s unlikely that sentience occurs solely in the cortex, but rather is an emergent property of complex neural networks.

Second, if we look at the evolution of the mammalian cortex, we can see that it stole most of its executive functions from other parts of the brain over evolutionary time. That is to say, many of its functions already occurred elsewhere in the brains of other animals.

Let me provide an example. In most animals, vision is processed in the optic lobes. In mammals, this occurs in the cortex. If we follow the argument of J. B. L. Smith, James Rose, and Brian Key, as laid out in the article (and which hasn’t changed for 60 years), we must conclude that any animal that lacks a cortex cannot see. But fish clearly see. Thus the argument that fish don’t feel pain because they don’t have a mammalian brain is laughable at best, and at worst willfully ignorant of evolutionary processes.

By the way, birds also don’t have a mammalian brain, and we don’t seem to be having any discussion about animal welfare in that context. So why fish? Could it be the big business angle?

Culum Brown

What’s so great about the “great fish pain debate”? Troy Vettese, Becca Franks, and Jennifer Jacquet highlight the slippery-slope nature of the argument—if fish feel pain, then perhaps they can also suffer, and if they suffer, what are the knock-on effects for the welfare of fish in the internationally prosperous fish food industry? The fish pain debate is like the proverbial finger in the dike. What then are the principal arguments underlying the fish pain debate?

On one side, we have those who believe that fishes’ behavioral response to noxious stimuli (e.g., a fish hook) is proof that these animals feel pain—that the creature has an inner awareness of the hook as piercing, unpleasant, agonizing. They find it difficult to imagine why a fish would try to escape a hook unless it were feeling pain. You would not be wrong in thinking that this line of argumentation is tainted by circular reasoning. Load the behavior definitionally as pain behavior, and it will follow, by definition, that anything exhibiting that kind of behavior feels pain.

On the other side are those who demand real—not imaginary, not definitional—evidence for fish feelings. They argue that evolution provides the reason why fish respond the way they do to environmental stimuli, and they have further demonstrated that fish lack the neural hardware necessary for pain. A simple analogy helps here. In dark underwater caves in Mexico, there are fish that have evolved to behave and survive without the sensation of sight. The Mexican blind cavefish lack eyes—that is, they lack the necessary neural hardware for experiencing light. It may be hard to imagine how these fish could possibly survive without sight, but they do so. Ipso facto, failure to imagine how fish could evolve and survive without the neural hardware necessary for pain is not itself evidence for fish pain.

The fish pain debate begins at different times for different people—but it certainly did not begin a mere 50 years ago with racial overtones in one lab in South Africa, as these authors suggest. For some, it began in the seventeenth century with Descartes questioning the assumption that animals are capable of thought or consciousness. For others, it materialized with the Nobel prize-winning British neurophysiologist Charles Scott Sherrington, who characterized the difference between nociception (neural processing of noxious stimuli without subjective experience—that is, without feeling) and pain (the subjective experience or feeling of nociception). Vettese et al. simply ignore a vast literature on this matter. Such grandstanding needs to be exposed for what it is, and must be swiftly expunged from this debate.

How can we move forward from here? Those who believe in fish pain need to stop relying on the limitations of their imagination and adopt modern neuroscientific approaches that raise serious doubts that “feelings” are necessary for complex behaviors and survival in organisms. Critical to this is the distinction between nociception and pain, a distinction we need to understand for our own behaviors, let alone that of fish. The welfare of fish would be better served by the community adopting objective measures of health and well-being, rather than resorting to folk beliefs in imaginary fish feelings.

Brian Key

Deborah Brown

Troy Vettese and coauthors provide rewarding neocortical stimulus in their review of the fish pain debate. They reveal many dynamics of postnormal science in the manageable microcosm of the regulation of catch-and-release angling. At the core lies scientific uncertainty in the value-laden debate on animal welfare. Environmentalists and recreational anglers are opposing issue advocates, selectively interpreting the available science to influence regulation of sport fishing. The evidence faces over-critical challenge, and the politics is scientized.

Simultaneously, the narrative thread aligns history with stakeholders who weaken the objectivity of the analysis. In tune with societal context, vocabulary, and values after a decade of Apartheid, the South African ichthyologist J. L. B. Smith is quoted twice about pain: that fish were too primitive to appreciate it (lacking a developed neocortex), and a racist distinction regarding a greater sensitivity to pain in “Whites” versus “Negroids.” The authors subsequently claim, “Much of the scientific research relevant to the debate over fish pain has built on foundations of bad evolutionary theory and poorly reasoned assumptions about brain function informed by the racial pseudoscience of Apartheid South Africa.”

Subsequent science is politicized, and discredited by association. The authors conclude by voicing the complementary perspective of current environmental ethics, which similarly reflects the societal context, vocabulary, and values of 2020. It is suggested that global warming, nutrient pollution, and oxygen depletion are great sources of suffering by fish, and this should command greater attention in debate on animal ethics. Two meanings of “suffer” are conflated. The suffering of a fish with a hook in its mouth cannot be contrasted with a population-size suffering by anthropogenic environmental insult. Are the individual fish in pain? In perhaps less than 60 years this argument will appear as quaint and value laden as Smith’s are to us today.

For two decades I studied the development of the nervous system of the fruitfly Drosophila, a genetic model organism. Drosophila and vertebrates employ equivalent genes for experiencing pain, and the behaviors elicited by pain are also equivalent. In distinction to nociception, which can elicit an involuntary avoidance response, pain elicits learned avoidance behaviors. Many arthropods and mollusks learn new behaviors to avoid pain. Vettese et al. cite Victoria Braithwaite’s report of rubbing behavior in trout elicited by a persistent irritation of the lip. Similar rubbing behavior (in crabs) and excessive grooming (in prawns and flies) have been described. The hermit crab and the octopus will also incur pain if the reward, such as food, is sufficient. Many invertebrates can learn to avoid pain by associating it with a stimulus, like Pavlov’s bell. If an animal can improvise and remember new behaviors to reduce exposure to noxious stimuli, have these stimuli caused suffering? By the criteria applied to fish, the answer would be yes.

Braithwaite also associated the sophistication of “spatial intelligence” in fish with the capacity to experience pain. Perhaps the spatial intelligence of wasps and bees is not on par with fish. If the pain and suffering of insects at the hands of humans had the same emotional value as that of a fish impaled by a hook, this article could be rewritten, substituting “fruitfly” for “fish,” confounding those who pursue policies that reduce anthropogenic animal suffering.

J. Roger Jacobs

Time and again, some of the most exciting insights in science happened because someone asked good why questions. And it is precisely the why question that Vettese et al. ask in their article on fish pain that makes their contribution daring and potentially of great consequence for the future of animal welfare science.

The authors rightly do not dwell on whether fish feel pain, a question that has received ample attention for decades. Instead, they ask why the topic has come to be so polarized and controversial in the first place. Vettese et al. do an excellent job at recounting how human values and competing interests have shaped the terms of the debate and the lines of research—but the answer to the why remains incomplete.

As scientists, we don’t seem to agree on what the phenomenon of pain is (even within fairly narrow limits), let alone on what sorts of living systems experience pain (or not). But whatever the definition, pain contributes to the survival, growth, and reproduction of a living system. As an evolutionary adaptation, there should be no reason for a debate over fish pain. So what are we really missing here?

The core issue is that different arguments about what does or doesn’t count as pain are based on mostly hidden assumptions. The most pervasive one is the anthropocentric myth of discontinuity between human and “other” beings. In this view, a fish—or any nonhuman “other”—is framed as a discrete object, a static generality that we understand from our separate viewpoint. Pain, then, is a property that human observers discretionarily ascribe (or not) to the mind-less fish. In other words, fish pain exists only if science “produces” it as such.

The objectified fish hanging at the end of an angler’s line has no stories to tell—no narrative of pain that would allow for its inclusion in the human world of relationships, feelings, consciousness, and pain. This fish is a fabrication of the dominant scientific paradigm that separates humans from the rest of life. But of course this does not describe the world we live in, a world of subjectivities, continuities, and “we-ness.” By refining our attention, we can see the interconnectedness of life forms, the famous “entangled bank” that Charles Darwin wrote about in the final paragraph of The Origin of Species.

Because fish and humans are already entangled (whether or not we are aware of it), there is no fish pain that is separable from the human experience of pain. And there is no need to feel exactly what the fish feels. In fact, understanding fish pain has nothing to do with the scientific identification of the fish’s subjective experience and everything to do with cultivating an attention that allows us to know both human and fish within the relational body of reciprocity and proximity. The continued misunderstanding of this is a sign of ruptured relationships.

Indeed, the contention at hand is less about fish pain and more about our ecologically disastrous relationships with life. If Darwin’s influence was as firmly established in our scientific thinking as we like to believe, the full understanding that human life exists in a dynamic process of co-emergence, interdependence, and kinship with all “others” should be more radically embodied in our actions than it arguably is.

Monica Gagliano

Ivan Darío Vargas Roncancio

Troy Vettese et al. conclude that “much of the scientific research relevant to the debate over fish pain has built on foundations of bad evolutionary theory and poorly reasoned assumptions about brain function informed by the racial pseudoscience of Apartheid South Africa.” They justify this statement by claiming that for “scientists and advocates who argue that fish cannot feel pain, the reasoning has remained the same for decades: fish do not have a neocortex,” and that this argument is based on publications of J. L. B. Smith in 1968. Smith, who lived in South Africa, was an avid angler and racist who distinguished between primitive and advanced animal species similar to his racial distinction between people of different color.

First of all, the question of whether fish feel pain is still an open, and the only current valid answer is: we don`t know exactly. It is correct that fish do not have a neocortex, but this is no longer the central question of debate. Vettese and coauthors ignore much of the current literature on this topic that has indeed expanded in depth and rigor. The missing neocortex in fish is only a small part of a complex discussion, and Smith and his arguments are unimportant in current literature. I would even assume that only few of the visible authors in the debate are aware of what Smith had been writing in the 1960s.

Therefore, one of the main assumptions of Vettese et al. does not reflect current knowledge and debate. Claiming that critical authors of the debate follow bad evolutionary theory based on racial pseudoscience has simply no basis and is utterly unscientific. Just because Smith was known to be a racist, his personal and historical background cannot be used to blame current researchers criticizing the fish pain debate on a scientific basis.

The arguments of Vettese et al. follow a scheme already known from animal liberation and animal rights organizations. By fighting against human use of animals as a resource, including fish, animal rights organizations such as PETA have repeatedly equated speciesism with human racism. Transfer of such activism into open scientific debate is offensive, ignoble, and harmful for both objective research and social discussion. Vettese et al. assume that fish-pain sceptics view the sense of fish as being primitive, which discriminates moral interests compared with other species, and in turn equates this belief with human racism. This analogy does not make sense because the sceptics simply criticize scientific methods and conclusions drawn from (mostly) behavioral experiments, which is a common and important part of scientific discussion. Therefore, the authors have missed an opportunity to foster a scholarly debate.

Thomas Klefoth

In my experience as shark ethologist who writes about wild sharks and fish behavior, I have not experienced the fish pain debate as being between animal activists and fishermen, as Troy Vettese and coauthors claim. Every time I mentioned fish or shark suffering in an article in a post about wildlife behavior, fishermen attacked it—not scientists or veterinarians. So I was obliged to defend my observations.

Therefore, I see this issue as an attack on scientific research into animal capabilities by fishing interests. It is another example of the domination of industry, along with climate change denial, the support of the shark-fin trade, the benefits of hunting, and other industry-backed attacks on the biosphere. As Vettese et al. wrote, the multibillion dollar fishing industry has successfully muddied the waters.

After all, to anyone who has watched a fish eating a sea urchin, it is obvious that fish feel pain. The evolution of a host of oceanic stingers has depended precisely on the sensitivity of their mouth parts. Fish have highly developed cognitive abilities, as is well established in the literature, as well as “higher brain functions.” Birds, known to be highly sensitive and intelligent, also lack a neocortex, as do fish, and no one argues that they do not feel pain. It is well known that in mammals the neocortex took over some functions that had already developed in vertebrates. So the argument that the lack of a neocortex results in the inability to feel pain should have been discarded long ago.

But no matter what evidence is brought up, fishermen argue around it, and the only reason their arguments are still being taken seriously is because of the numbers of fishermen and fishing journals, along with the power of industry. Their anthropocentric arguments, ignoring evolution, are based on ideas that have been long since rebutted by science, so they amount to pseudoscience.

The psychologist Dan Kahan and colleagues have found that people, including scientists, often fail to question their political beliefs in the face of scientific discoveries that contradict them. They interpret data in such a way that they conform with their political vantage point. This seems to be part of the problem in the acceptance of the fisheries’ outcry that fish don’t feel pain.

But no evidence has ever been produced to support the idea that an animal could survive without this important warning sensation. It would result in inappropriate behavior that would send the animal straight into evolution’s garbage can. Only a small percentage of fish live to adulthood, and any such weakness would doom them.

So while animal welfare activists may feel obliged to take on the fishing industry and try to pass laws that protect fish from cruelty, in the scientific effort to understand life, surely academia should resist pseudoscientific ideas that clearly support industry.

Ila France Porcher

Troy Vettese, Becca Franks, and Jennifer Jacquet provide a compelling history of the question “do fish feel pain?” while still leaving mysterious the question of why it evolved as it did. The question is slightly absurd on its face: as the authors point out, pain is inherently subjective. Standardized metrics for pain in human patients remain controversial, given the opioid epidemic and medicine’s history of racializing pain. If doctors do not consistently validate pain when it occurs in people, what chance do we have with fish?

My main question, however, is agnotological; that is, it deals with culturally induced ignorance or doubt. The authors rightly highlight the perverse logic of focusing do-fish-feel-pain campaigns on angling and recreational fishing rather than on commercial fishing, where the vast majority (roughly 98% by weight) of fish are caught. They attribute this to the momentum of science and quirks of West German law, but it remains unclear to me why decisions were made by these animal rights groups to go after anglers rather than commercial fishers.

This is the kind of question that frustrates historians, since it may ultimately be unanswerable, but is important for understanding divisions within the multiple communities that claim to represent the interests of fish. The focus on whether fish feel pain from being hooked serves as an example of a larger split between the animal rights and environmentalist movements, and highlights the division between the individualist/Kantian ethics of the former and the communalist/utilitarian ethics of the latter.

Hook-and-line fishing is employed in recreational fishing, but also in some forms of commercial fishing that are actually environmentally preferred because they can target only desired species and reduce or eliminate by-catch. Hook-and-line fishing also has negligible environmental impacts compared with gill-nets and other gear that can entangle marine mammals, turtles, seabirds, and nontarget fish, and bottom-trawling that can damage benthic ecosystems. For these reasons, sustainability certification schemes favor hook-and-line fishing over more environmentally destructive techniques.

As the authors mention, we do not know the severity of pain that these other methods might cause, because there has been no research on the subject, but there is little reason to think it would be less that from hook-and-line fishing. Additionally, anglers are often allies of environmental movements, advocating for the preservation of lakes, streams, and rivers. So why target them, rather than commercial net fishing?

One possible answer is the aphorism “one death is a tragedy; a million deaths is a statistic.” For engaging empathy, the experience of a singular fish, captured by a singular angler, may make a more compelling story than the billions that occur in aquaculture and commercial fishing.

The divisions between individualist and collectivist approaches to animal welfare are important, because they can emerge in more fraught contexts such as captive breeding of endangered species, where individual-oriented anti-zoo activists clash with species-oriented conservationists. They also matter if we are to take fish pain seriously and consider how commercial fisheries and aquaculture might be made more humane, as the authors here urge.

Aaron Van Neste

I was very pleased to see the article addressing the question of fish sentience and pain, as this is a much-overlooked issue in ethological research.

Simply from an evolutionary perspective, it makes no sense whatsoever that a complex, conscious organism with a central nervous system would not have developed as fine-tuned an ability to feel pain, pleasure, and other sensations as have mammals, reptiles, amphibians, avians, and other vertebrates. How could an animal such as the bluefin tuna possibly survive in the wild for up to 40 years without an ability to sense harm to itself—to say nothing of the Greenland shark, which can live for centuries? Fish have highly developed senses of smell, taste, and electromagnetism (a sense humans do not have); what then are the odds that the much more basic ability to feel pain was omitted by nature?

As the authors observe, scientific research shows plainly that fish do indeed suffer. Nor is there any reason to suppose that their subjective experiences of pain are any less acute than our own. Though we tend to view fish as little more than animate objects, a growing body of evidence suggests that fish have quite complex consciousness. Archer fish, for example, have been found to recognize individual human faces. Sea bream not only have emotions, but their emotional responses depend on each individual fish’s subjective evaluation of what’s occurring in its environment.

Fish have excellent memories, recalling experiences months later. Dozens if not hundreds of other studies have also demonstrated advanced cognition in fishes. According to Colum Brown, a researcher with the Behaviour, Ecology, and Evolution Laboratory at Macquarie University in Australia, “Most aspects [of] their cognitive abilities are just as good as most terrestrial animals, and in many cases exceed them.”

For a long time, researchers also believed that only humans could manipulate tools, solve problems intelligently, exhibit empathy, engage in altruistic behaviors, and use language, among other skills. Now we know this isn’t true. Complex consciousness is to be found not only in primates or mammals, but across the phylogenetic spectrum, even among birds and cephalopods, whose paths diverged from our own tens of millions of years ago. To deny the evidence for similar consciousness in fish therefore amounts to prejudice and wishful thinking, nothing more.

John Sanbonmatsu

Troy Vettese and coauthors ask, is recreational angling painful? But in looking for an answer, they ignore numerous studies that have found negative evidence. As but one example, hooked Atlantic cod exhibit head shaking but no “pain behaviors”—reflecting what the researchers called a possible “resiliency to tissue damage in the mouth area related to the tough nature of the Atlantic cod diet.”

The authors also explored definitions of welfare, but were silent on why ill-defined feelings-based criteria should be prioritized over functional criteria used for decades that can actually be measured objectively.

For example, some new definitions for pain encompass rubbing behavior that for hundreds of years have been considered signs of fish having a common parasitic disease called Ich. When this condition is suddenly declared painful, the perils of lowering the bar for “pain” become apparent. Without skepticism it leads to a slippery slope of pain being declared in nearly anything that moves.

The authors acerbically state, “Scientists skeptical of fish pain often present anglers as environmental stewards.” However, many other scientists, environmentalists, and politicians agree with this statement, because its true. There is abundant evidence that anglers are often the only community group actively improving waterways by fighting pollution and overfishing and by protecting and restoring fish habitat, all of which improve aspects of fish welfare, as the authors discuss near the end of the article.

By attempting to discredit skeptical scientists, the authors reveal their own biases and do a disservice to science by depriving it of its essence—the application of organized skepticism and the need for verification of results. This becomes especially important when the results influence important regulatory decisions. Skepticism will ensure better policy outcomes that work in the real world, without leading to inappropriate worries about fish welfare.

Ben Diggles