Any experienced fisherman fishing from a pond different fish, already at the hooking stage can tell which inhabitant of the underwater kingdom he will have to deal with. Strong jerks and desperate resistance of pike, powerful “pressure” to the bottom of catfish and pike perch - these “calling cards” of fish behavior are immediately determined by skilled fishermen. There is an opinion among fishing enthusiasts that the strength and duration of a fish’s fight directly depends on its sensitivity and the degree of organization of its nervous system. That is, it is implied that among our freshwater fish There are species that are more highly organized and “nervous-sensual”, and there are also fish that are “coarse” and insensitive. This point of view is too straightforward and essentially incorrect. To know for sure whether our inhabitants of reservoirs feel pain and how exactly, let’s turn to rich scientific experience, especially since specialized “ichthyological” literature has been citing detailed descriptions features of the physiology and ecology of fish. INSERT. Pain is a psychophysiological reaction of the body that occurs when the sensitive nerve endings embedded in organs and tissues are severely irritated. TSB, 1982. Unlike most vertebrates, fish cannot communicate pain by screaming or moaning. We can judge the pain sensation of a fish only by the protective reactions of its body (including its characteristic behavior). Back in 1910, R. Gopher established that a pike at rest, when artificially irritating the skin (prick), moves its tail. Using this method, the scientist showed that “ pain points The fish are found all over the surface of the body, but they are most densely located on the head. Today it is known that due to the low level of development of the nervous system, pain sensitivity in fish is low. Although, undoubtedly, the cut fish feels pain (remember the rich innervation of the head and oral cavity of fish, taste buds!). If the hook has penetrated into the gills of a fish, the esophagus, the periorbital region, its painful sensations in this case, they will be stronger than if the hook pierced the upper/lower jaw or caught on the skin. INSERT. The behavior of fish on a hook does not depend on the pain sensitivity of a particular individual, but on its individual reaction to stress. It is known that the pain sensitivity of fish strongly depends on water temperature: in pike, the speed of nerve impulses at 5ºC was 3-4 times less than the speed of excitation at 20ºC. In other words, fish caught in summer are 3-4 times sicker than in winter. Scientists are confident that the fierce resistance of pike or the passivity of pike perch and bream on a hook during fishing is only to a small extent due to pain. It has been proven that the reaction of a particular fish species to being caught depends more on the severity of the stress received by the fish. Fishing as a lethal stressor for fish For all fish, the process of being caught by an angler and fishing is the greatest stress, sometimes exceeding the stress of escaping from a predator. For anglers who profess the catch-and-release principle, it will be important to know the following. Stress responses in vertebrates are caused by catecholamines (adrenaline and norepinephrine) and cortisol, which act over two distinct but overlapping time periods (Smith, 1986). Changes in the body of fish caused by the release of adrenaline and norepinephrine occur in less than 1 second and last from several minutes to hours. Cortisol causes changes that begin in less than 1 hour and sometimes last for weeks or even months! If the stress on the fish is prolonged (for example, during long-term fishing) or very intense (severe fright of the fish, aggravated by pain and, for example, lifting from great depths), in most cases the caught fish is doomed. She will certainly die within 24 hours, even if released. This statement has been repeatedly proven by ichthyological researchers in natural conditions (see “Modern Fishing”, No. 1, 2004) and experimentally. In the 1930-1940s. Homer Smith observed a lethal stress reaction of an anglerfish to being caught and placed in an aquarium. The frightened fish sharply increased the excretion of water from the body through urine, and after 12-22 hours it died... from dehydration. The fish died much faster if they were injured. Several decades later, fish from American fish ponds were subjected to rigorous physiological studies. Stress in fish caught during planned events (transplantation of breeders, etc.) ), was due to increased activity of fish during pursuit by a seine, attempts to escape from it, and short-term exposure to air. The caught fish developed hypoxia (oxygen starvation) and, if they also experienced loss of scales, the consequences in most cases were fatal. Other observations (of brook trout) have shown that if a fish loses more than 30% of its scales when caught, it dies within the first day. In fish that had lost part of their scales, swimming activity faded, individuals lost up to 20% of their body weight, and the fish died quietly in a state of mild paralysis (Smith, 1986). Some researchers (Wydowski et al., 1976) noted that when catching trout with a line, the fish were subjected to less stress than when they lost their scales. The stress response was more intense at high water temperatures and in larger individuals. Thus, an inquisitive and scientifically “savvy” fisherman, knowing the peculiarities of the nervous organization of our freshwater fish and the possibility of them acquiring conditioned reflexes, learning ability, and their attitude to stressful situations, can always plan their vacation on the water and build relationships with the inhabitants of the Neptunian kingdom. I also sincerely hope that this publication will help many fishermen to effectively use the rules of fair play - the “catch and release” principle... Author: Novitsky Roman Aleksandrovich Candidate of Biological Sciences, Associate Professor of the Department of Zoology and Ecology of Dnepropetrovsk National University. Professional ichthyologist.
Recently, scientists - and not only them - are increasingly thinking about whether animals feel pain. Let’s say that no one has any doubts about animals and birds. But what can be said, for example, about crustaceans? On the one hand, these are living beings, and by default we believe that all living things can experience pain. On the other hand, at all times there were enough people who believed that some lower organisms were simply not capable of experiencing anything like that.
Fishing with a cormorant.
In fact, the question of whether lower organisms feel pain is not as simple as it seems. We judge other people's pain by our own, that is, we extend our painful sensations to another person - or to a bird, or an animal, or a fish. In humans, this sensation arises thanks to special receptors, therefore, it would seem that the ability to feel pain can be judged by whether the animal has the corresponding organs. However, with you and I, things are not limited to just receptors. Painful sensations are influenced by the emotional state: fear, for example, increases pain, and in general sensations of this kind can occur without any physical injury. In addition, in an unconscious state, we simply do not feel signals from pain receptors. Those involved in pain research divide pain into receptor pain and pain that is processed in the brain and leads to specific behavioral and physiological responses.
Therefore, it is not surprising that many scientists strongly doubt the ability, for example, of fish to feel pain - at least in the human sense of the word. In an article appearing in Fish and Fisheries, researchers from several research centers in Germany, the US, Canada and Australia detail where such doubts come from. Firstly, there is no neocortex in the fish brain, and pain signals in mammals come here, in the neocortex. Secondly, mammals have special nerve fibers that sense pain stimuli - and all of them do not have these pain fibers. cartilaginous fish(sharks and rays), and most bony fish.
Some simple pain receptors are still present in fish, and the fish themselves react to injuries. However, researchers point out that in most studies on the pain sense of fish, the authors were too carried away by the obvious interpretation of their results. For example, an injured fish may stop eating, but we don't know what exactly caused it to behave this way. Here, generally speaking, we are faced with a much more significant problem: the problem of anthropomorphism in biology. We believe that a creature experiences pain in exactly the same way as we do, without having any prerequisites for such a judgment (unless, of course, we consider mystical reasoning about the “single life force permeating nature,” etc.) as such. Do fish recognize pain? This requires consciousness - but does a fish have it? If a creature moves and “lives,” this does not mean that it is structured in the same way as we are - for example, completely living fish do not have such and such nerves and areas of the brain.
In addition, it is known that fish do not feel pain in situations where any animal would have felt it long ago. On the other hand, well-known painkillers, like morphine, either have no effect on fish at all, or they do, but in monstrous quantities that would long ago kill some small mammal.
Let us repeat: the question of whether fish feel pain is far from idle. Recently, in some countries, various kinds of legal restrictions have appeared on cruelty to living beings, and by living beings we mean not only monkeys and rabbits, but also fish. From the point of view of a simple Western European, who has lived the last few decades side by side with various “greens,” the life of, for example, fish on fish farms seems unbearable. However, as research shows, if fish feel pain, it occurs in them through some physiological mechanisms other than in humans.
How to convey this to the average “green” man in the street, overwhelmed by human, all too human, sympathy for all living things? Unfortunately, no country seems to have laws yet that would prohibit good intentions from entering into an alliance with well-meaning ignorance.
Although their sensory experiences are different from ours, they are no less interesting and varied than those of higher vertebrates. And, of course, the full development of these organs is associated with the fish’s habitat - water.
1. Vision.
The importance of vision is not so great in aquatic inhabitants compared to terrestrial ones.
It's connected Firstly, with the fact that with increasing depth the illumination decreases significantly, secondly, very often fish are forced to live in conditions of low water transparency, thirdly, the aquatic environment allows them to use other senses with much greater efficiency.
Almost all fish have eyes located on both sides, which provides them with panoramic vision in the absence of a neck and, as a consequence, the impossibility of turning the head without turning the body. Low elasticity of the lens makes fish myopic and they cannot see clearly at long distances.
Many species have adapted their vision to highly specific living conditions: coral reef fish have not only color vision, but are also able to see in the ultraviolet spectrum; some fish that collect food from the surface of the water have eyes divided into two halves: the upper one sees what is happening in the air, the lower one - under water, in fish living in mountain caves, the eyes are generally reduced.
2. Hearing.
Oddly enough, fish have well-developed hearing, despite their lack of external signs. Their hearing organs are combined with the balance organs and are closed sacs with otoliths floating in them. Very often the swim bladder acts as a resonator. In a dense aquatic environment, sound vibrations travel faster than in air, so the importance of hearing for fish is great.
It is a well-known fact that fish in water hear the footsteps of a person walking along the shore.
Many fish are capable of making various purposeful sounds: rubbing their scales against each other, vibrating various parts of the body and thus carrying out sound communication.
3. Smell.
The sense of smell plays a significant role in the life of fish.
This is due to the fact that odors spread very well in water.
Everyone knows that a drop of blood falling into the water attracts the attention of sharks located several kilometers from this place.
In particular, salmon going to spawn use their sense of smell to find their way home.
Such a subtle sense of smell is developed in fish due to the fact that the olfactory bulb occupies a significant part of their brain.
4. Taste.
Flavoring substances are also perfectly distinguished by fish, because perfectly soluble in water. Taste buds are located not only in the mouth, but also throughout the rest of the body, especially on the head and antennae. For the most part, the taste organs are used by fish to search for food, as well as for orientation.
5. Touch.
Fish have ordinary mechanical receptors, which, like the taste organs, are located mainly at the tips of the antennae, and are also scattered over the skin. However, in addition to this, fish have a completely unique receptor organ - lateral line.
This organ, located along the middle on both sides of the body, is capable of perceiving the slightest fluctuations and changes in water pressure.
Thanks to the lateral line, fish can obtain information about the size, volume and distance to distant objects. With the help of the lateral line, fish are able to go around obstacles, avoid predators or find food, and maintain their position in the school.
6. Electrosensitivity.
Electrosensitivity is highly developed in many species of fish. It is an excellent addition to the already listed sense organs and allows fish to defend themselves, detect and obtain food, and navigate.
Some fish use electrolocation for communication, and thanks to the ability to sense the Earth's magnetic field, they can migrate over very long distances.
Do fish feel pain?
A positive answer to this difficult question could mobilize public opinion against harmless fishermen, as is already the case with lovers of another bloody activity - hunting. Moreover, passions played out in one of the most concerned about animal rights countries in the world - Great Britain. Yes, yes, despite the entire English cult of hunting, the British are by no means inclined to idealize this activity.
Previously, most scientists believed that pain was unknown to fish - they simply did not have the appropriate nerve receptors. A group of Scottish researchers from the Roslyn Institute and the University of Edinburgh set out to test this popular belief.
The river rainbow trout was chosen as the guinea pig. It must be said that such experiments on fish are a thankless task. These cold-blooded animals are known to be mute from birth, and they do not always demonstrate motor reactions. Who knows what the fish is thinking about and does not consider it necessary to tell us?
The biologists' conclusion, based on a series of inhumane experiments, is that "the profound behavioral and physiological changes found in trout exposed to external stimuli are comparable to those observed in higher mammals."
Let us briefly describe these external irritants: mechanical and thermal influences, as well as bee venom and acetic acid applied to the fish lips. Next, the behavior of individuals from the tortured group was compared with the reactions of control fish exposed to harmless substances.
Trout under the influence of poisons rubbed their lips against the walls of the aquarium and made swaying movements from side to side, which is typical in painful situations, for mammals and humans. Respiratory disorders were also observed in fish.
In addition, at least 58 receptors were found on the heads of trout that respond to at least one of the painful stimuli. 22 receptors simultaneously responded to mechanical pressure and thermal influence, and another 18 were additionally irritated by chemicals. Multimodal receptors were discovered in fish for the first time, although they have long been studied in amphibians, birds and mammals.
The skeptical part of the scientific community is not convinced by the results of the experiments. It is argued that even if fish react to pain, they are unlikely to actually experience it. Neuroscientists believe that the fish brain lacks the necessary mechanisms. Meanwhile, it is very difficult to find out exactly how another creature feels pain. Even two people's pain tolerance thresholds can be completely different. Sometimes a person reacts reflexively to pain even in an unconscious state.
In the end, scientific debates reached a dead end, arguments met counterarguments, and no one was convinced. Therefore, we should expect continued experiments on unperturbed fish.
Are fish capable of experiencing pain? This question is as old as the ability of man to fish, but it has never been answered definitively. According to a recent study, fish brains lack the necessary pain receptors that enable them to experience pain in the same way that humans and other living organisms do.
Yes, fish have nociceptors, that is, sensory nerve endings that become excited when physically damaged by objects or during relevant events, sending warning signals to the brain. But these receptors in fish act very differently from those in humans, say the study authors.
“Even if fish were conscious, there is no reason to assume that their ability to perceive pain would be the same as that of humans,” emphasize the authors of the study, recently published in the journal Fish and Fisheries.
A group of nerve endings known as C-fiber nociceptors are responsible for the sensation of pain in humans. Researchers believe they are rare in fish with fins and completely absent in sharks and rays. Another group of endings, namely A-delta nociceptors, causes a simple, reflexive avoidance response, which is fundamentally different from true pain sensations, the authors write.
However, critics say the researchers are ignoring a number of other studies that contradict their findings.
So, in 2003, bee venom or an acidic solution was injected into the lips of fish. The reaction of the fish was immediate - they began to rub their lips against the side walls or bottom of their tank, roll from side to side and breathe with such a frequency that is observed only when swimming at high speed.
And a 2009 study found that after a painful event, fish exhibit defensive or avoidance behavior, indicating that the body experienced pain and remembered it.
“There are a number of studies that we believe provide evidence that fish do experience pain, and this opinion will remain with us,” said the chairman of the British Royal Society for the Prevention of Cruelty to Animals.
The debate over whether fish experience pain has sowed the seeds of discord between fishing enthusiasts and animal rights activists, but one of the authors latest research believes the divisive debate has no basis.
"I think fish welfare is a very important aspect, but I also think fishing and science are equally important, says Robert Arlinghaus of the Institute for Freshwater Ecology and Inland Fisheries, Berlin, Germany. – The issue of pain, and whether fish experience it, surrounds a number of conflicting issues, and fishermen are often perceived as cruel and sadistic. This is an unnecessary social conflict."
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Vyacheslav Dubynin
The pain sensitivity system is one of the sensory systems that belong to the category of body sensitivity. There is skin sensitivity, there is muscle sensitivity, there is internal sensitivity, there is pain sensitivity. Accordingly, there are separate pain receptors that conduct pathways specifically for pain signals, as well as processing centers in the spinal cord, in the brain, which deal with pain very specifically. Physiologist Vyacheslav Dubynin about prostaglandins, the principles of operation of analgesics and the occurrence of chronic pain.
Prozorovsky V. B.
Anesthesia is one of the greatest achievements of medicine, thanks to which it became possible to overcome pain during surgery. Without anesthesia, the development of surgery to the modern level would simply be impossible. But although narcotic substances have been used for more than 150 years, there is still no complete understanding of the mechanisms of anesthesia.
Can fish sleep? For a long time, scientists puzzled over this question, but the results of a recent study showed that after a restless night, fish like to take a nap.
The vast majority of differences between males and females are related to reproduction in one way or another. They have different genital organs and corresponding skeletal structure features. External differences also relate to reproduction: the male has horns, mane, tail and bright coloring, while the female looks much more modest, or, conversely, the female is large, and the male next to her is barely noticeable. Sexual dimorphism, which affects internal organs not related to reproduction, is an extremely rare phenomenon. Recently, British and American researchers discovered another striking case of sexual dimorphism internal organs, not related to reproduction.
Wildlife often baffles researchers, presenting them with various “technical” mysteries. One of them, which has puzzled more than one generation of scientists, is how many marine animals, fish and dolphins manage to move in dense water at speeds that are sometimes inaccessible even for flying in the air. Swordfish, for example, swims at a speed of 130 km/h; tuna - 90 km/h. Calculations show: in order to overcome water resistance and gain such speed, the fish needs to develop the power of a car engine - about 100 horsepower. Such powers are unattainable for them! We can only assume one thing: fish somehow “know how” to greatly reduce water resistance.
Versatile experiments allowed biologists to decipher all the links in the adaptive chain, during which sighted fish in open waters turned into blind cave dwellers. This is a rare case where it was possible to prove the realism of a hypothetical plot.
