To the question Do fish hear? Do they have hearing organs? given by the author Vital the best answer is The fish's hearing organ is represented only by the inner ear and consists of a labyrinth, including the vestibule and three semicircular canals located in three perpendicular planes. In the fluid inside the membranous labyrinth, there are auditory pebbles (otoliths), the vibrations of which are perceived by the auditory nerve. Neither the outer ear nor the tympanic membrane no fish. Sound waves are transmitted directly through tissues. The labyrinth of fish also serves as an organ of balance. The lateral line enables the fish to navigate, to feel the flow of water or the approach of various objects in the dark. The lateral line organs are located in a canal embedded in the skin that communicates with external environment with holes in the scales. There are nerve endings in the canal. The hearing organs of fish also perceive vibrations of the aquatic environment, but only higher-frequency, harmonic or sound ones. They are arranged more simply than in other animals. Fish do not have an external or middle ear: they do without them due to the higher sound permeability of water. There is only a membranous labyrinth, or inner ear, enclosed in the bony wall of the skull. Fish hear, and, moreover, perfectly, so the angler must be completely silent while fishing. By the way, it became known quite recently. Some 35-40 years ago, they thought that fish were deaf. According to sensitivity, hearing and the lateral line come to the fore in winter. It should be noted here that external sound vibrations and noises penetrate the fish habitat to a much lesser extent through the ice and snow cover. There is almost absolute silence in the water under the ice. And in such conditions, the fish rely more on their hearing. The organ of hearing and the lateral line help the fish to determine the places of accumulation of bloodworms in the bottom soil by the vibrations of these larvae. If we also take into account that sound vibrations decay in water 3,500 times slower than in air, it becomes clear that fish are able to detect bloodworm movements in the bottom soil at a considerable distance. Burrowing into a layer of silt, the larvae strengthen the walls of the passages with hardening secretions. salivary glands and make wave-like oscillatory movements in them with their bodies (Fig.), blowing and cleaning their home. From this, acoustic waves are emitted into the surrounding space, they are perceived by the lateral line and the hearing of fish. Thus, the more bloodworm is in the bottom soil, the more acoustic waves come from it and the easier it is for the fish to detect the larvae themselves.
Answer from Alexander Vodyanik[newbie]
they hear with their skin... they hear with their skin... I had a friend in Latvia who used to say that too: I feel it with my skin! "
Answer from User deleted[guru]
Koreans in the Sea of Japan catch pollock. They hunt this fish with hooks, without any attachment, but they always hang trinkets (metal plates, nails, etc.) over the hooks. A fisherman, sitting in a boat, twitches such a tackle, and the pollocks are going to trinkets. Catching fish without trinkets does not bring good luck.
Shouting, knocking, shots above the water disturb the fish, but it is more fair to explain this not so much by the perception of the hearing aid as by the ability of the fish to perceive the oscillatory movements of the water with the help of the lateral line, although the method of catching catfish is “on a shred”, on the sound produced by a special (hollowed out) shovel and reminiscent of the croaking of a frog, many are inclined to consider evidence of hearing in fish. Catfish approach this sound and take the angler's hook.
In L. P. Sabaneev's classic book "Fish of Russia", unsurpassed in its fascination, bright pages are devoted to the method of catching catfish for sound. The author does not explain why this sound lures the catfish, but cites the opinion of the fishermen that it is similar to the voice of catfish, which seem to cackle at dawn, calling for males, or to the croaking of frogs, which catfish like to eat. In any case, there is reason to believe that the catfish hears.
In the Amur there is a commercial fish silver carp, known for that keeps in a herd and jumps out of the water at the noise. You will go out on a boat to those places where the silver carp is kept, hit the oar harder on the water or on the side of the boat, and the silver carp will not be slow to respond: immediately several fish will jump out of the river with noise, rising 1-2 meters above its surface. Hit again, and again the silver carp will jump out of the water. They say that there are cases when silver carps jumping out of the water sink the small boats of the Nanais. Once in our boat, a silver carp jumped out of the water and broke the glass. Such is the effect of sound on the silver carp, apparently a very restless (nervous) fish. This fish, almost a meter long, can be caught without a trap.
“Don’t make noise here, otherwise you’ll scare away all the fish” - how many times have we heard a similar phrase. And many novice fishermen still naively believe that such words are spoken solely out of strictness, a desire to remain silent, superstitions. They think something like this: the fish swims in the water, what can it hear there? It turns out that there is a lot, so there is no need to be mistaken about this. To clarify the situation, we want to tell you what kind of hearing fish have and why they can easily be scared away by some sharp or loud sounds.
Those who think that carp, bream, carp and other inhabitants of water areas are practically deaf are deeply mistaken. Fish have excellent hearing - both thanks to the developed organs (inner ear and lateral line), and due to the fact that water conducts sound vibrations well. So it’s really not worth making noise during feeder fishing. But how well do fish hear? Just like us, better or worse? Let's consider this question.
How well do fish hear?
As an example, let's take our favorite carp: he hears sounds in the range of 5 Hz - 2 kHz. These are low vibrations. For comparison: we, people, at a not yet old age hear sounds in the range of 20 Hz - 20 kHz. Our perceptual threshold starts at higher frequencies.
So in a way fish hear even better than us, but up to a certain limit. For example, they remarkably catch rustles, bumps, pops, so it is important not to make noise.
Fish by ear can be divided into 2 groups:
they hear perfectly - these are cautious cyprinids, tench, roach
they hear well - these are more daring perches and pikes
As you can see, there are no deaf people. So slamming the car door, turning on the music, talking loudly with neighbors at the place of fishing is strictly contraindicated. This and similar noise can nullify even a good bite.
What organs of hearing do fish have?
At the back of the fish's head is a pair of inner ears responsible for hearing and sense of balance. Please note that these organs have no outlet.
On the body of the fish, on both sides, pass sidelines- original traps of the movement of water and sounds of low frequency. Such vibrations are recorded by fat sensors.
How do fish's hearing organs work?
With the lateral lines, the fish determines the direction of the sound, with the inner ears - the frequency. Then it transmits all these external vibrations with the help of fat sensors located under the lateral lines - along the neurons to the brain. As you can see, the work of the hearing organs is organized in a ridiculously simple way.
At the same time, the inner ear of non-predatory fish is connected to a kind of resonator - with a swim bladder. He is the first to receive all external vibrations and amplify them. And already these, increased power, sounds come to the inner ear, and from it to the brain. Due to such a resonator, cyprinids hear vibrations with a frequency of up to 2 kHz.
But in predatory fish, the inner ears are not connected to the swim bladder. Therefore, pikes, pike perches, perches hear sounds up to about 500 Hz. However, even such a frequency is enough for them, especially since they have better developed vision than non-predatory fish.
In conclusion, we want to say that the inhabitants of the water area get used to constantly repeating sounds. So even the noise of the outboard motor, in principle, may not scare the fish if they often swim in the pond. Another thing is unfamiliar, new sounds, all the more sharp, loud, prolonged. Because of them, the fish may even stop feeding, even if you were able to pick up good bait, or spawn, and as practice shows, the sharper her hearing, the sooner and earlier this will happen.
There is only one conclusion and it is simple: do not make noise when fishing, which we have repeatedly written about in this article. If you do not neglect this rule and observe silence, the chances of a good bite will remain maximum.
The question of whether fish hear has been debated for a long time. It is now established that fish hear and make sounds themselves. Sound is a chain of regularly repeated waves of compression of a gaseous, liquid or solid medium, i.e., in the aquatic environment, sound signals are just as natural as on land. Waves of compression of the aquatic environment can propagate with different frequencies. Low-frequency oscillations (vibration or infrasound) up to 16 Hz are not perceived by all fish. However, in some species, infrasonic reception has been perfected (sharks). The spectrum of sound frequencies perceived by most fish lies in the range of 50-3000 Hz. The ability of fish to perceive ultrasonic waves (over 20,000 Hz) has not yet been convincingly proven.
The speed of sound propagation in water is 4.5 times greater than in air. Therefore, sound signals from the shore reach the fish in a distorted form. Hearing acuity in fish is not as developed as in land animals. Nevertheless, some species of fish in experiments have quite decent musical abilities. For example, a minnow at 400-800 Hz distinguishes 1/2 tone. The possibilities of other fish species are more modest. So, guppies and eels differentiate two octaves that differ by 1/2-1/4. There are also completely musically incompetent species (bubbleless and labyrinth fish).
Rice. 2.18. The connection between the swim bladder and the inner ear different types fish: a- Atlantic herring; b - cod; in - carp; 1 - outgrowths of the swim bladder; 2- inner ear; 3 - brain: 4 and 5 bones of the Weber apparatus; common endolymphatic duct
Hearing acuity is determined by the morphology of the acoustic-lateral system, which, in addition to the lateral line and its derivatives, includes the inner ear, swim bladder and Weber apparatus (Fig. 2.18).
Both in the labyrinth and in the lateral line, so-called hairy cells act as sensitive cells. The displacement of the hair of the sensory cell both in the labyrinth and in the lateral line leads to the same result - the generation of a nerve impulse entering the same acoustic-lateral center of the medulla oblongata. However, these organs also receive other signals (gravitational field, electromagnetic and hydrodynamic fields, as well as mechanical and chemical stimuli).
The auditory apparatus of fish is represented by a labyrinth, a swim bladder (in bladder fish), a Weberian apparatus, and a lateral line system. Labyrinth. A paired formation - a labyrinth, or the inner ear of fish (Fig. 2.19), performs the function of an organ of balance and hearing. Auditory receptors are present in large numbers in the two lower chambers of the labyrinth, the lagen and the utriculus. The hairs of the auditory receptors are very sensitive to the movement of the endolymph in the labyrinth. A change in the position of the body of the fish in any plane leads to the movement of the endolymph, at least in one of the semicircular canals, which irritates the hairs.
In the endolymph of the saccule, utriculus, and lagena, there are otoliths (pebbles) that increase the sensitivity of the inner ear.
|
|
Rice. 2.19. Fish labyrinth: 1-round pouch (lagena); 2-ampoule (utriculus); 3-saccule; 4-channel labyrinth; 5- location of otoliths
Their total number is three on each side. They differ not only in location, but also in size. The largest otolith (pebble) is in a round bag - lagen.
On the otoliths of fish, annual rings are clearly visible, by which v some species of fish determine the age. They also provide an estimate of the efficiency of the fish's maneuver. With longitudinal, vertical, lateral and rotational movements of the body of the fish, some displacement of the otoliths and irritation of the sensitive hairs occur, which, in turn, creates the corresponding afferent flow. The reception of the gravitational field, the assessment of the degree of acceleration of the fish during throws, also fall on them (otoliths).
The endolymphatic duct departs from the labyrinth (see Fig. 2.18.6), which is closed in bony fish, and open in cartilaginous fish and communicates with the external environment. Weber apparatus. It is represented by three pairs of movably connected bones, which are called stapes (in contact with the labyrinth), incus and maleus (this bone is connected to the swim bladder). The bones of the Weberian apparatus are the result of the evolutionary transformation of the first trunk vertebrae (Fig. 2.20, 2.21).
With the help of the Weberian apparatus, the labyrinth is in contact with the swim bladder in all bladder fish. In other words, the Weber apparatus provides a link between the central structures sensory system with sound-perceiving peripherals.
Fig.2.20. The structure of the Weber apparatus:
1- perilymphatic duct; 2, 4, 6, 8 - bundles; 3 - stapes; 5- incus; 7- maleus; 8 - swim bladder (vertebrae are indicated by Roman numerals)
Rice. 2.21. The general scheme of the structure of the organ of hearing in fish:
1 - brain; 2 - utriculus; 3 - saccule; 4 - unifying channel; 5 - lagen; 6- perilymphatic duct; 7-stapes; 8- incus; 9-maleus; 10 - swim bladder
Swim bladder. It is a good resonating device, a kind of amplifier for medium and low-frequency oscillations of the medium. An external sound wave causes the wall of the swimbladder to vibrate, which in turn leads to displacement of the Weberian ossicular chain. The first pair of ossicles of the Weber apparatus presses on the labyrinth membrane, causing displacement of the endolymph and otoliths. Thus, if we draw an analogy with higher land animals, the Weberian apparatus in fish performs the function of the middle ear.
However, not all fish have swim bladders and Weber apparatus. In this case, the fish show low sensitivity to sound. In bladderless fish, the auditory function of the swim bladder is partially compensated by the air cavities associated with the labyrinth and the high sensitivity of the lateral line organs to sound stimuli (water compression waves).
Lateral line. It is a very ancient sensory formation, which performs several functions simultaneously in evolutionarily young groups of fish. Taking into account the exceptional importance of this organ for fish, let us dwell in more detail on its morphological and functional characteristics. Different ecological types of fish show various options lateral system. The location of the lateral line on the body of fish is often a species-specific feature. There are fish species that have more than one lateral line. For example, a greenling has four lateral lines on each side, hence
there is its second name - "eight-linear hir". In most bony fish, the lateral line stretches along the body (without interruption or interruption in separate places), reaches the head, forming a complex system of canals. The lateral line canals are located either inside the skin (Fig. 2.22), or openly on its surface.
An example of an open superficial location of neuromasts - structural units of the lateral line - is the lateral line in a minnow. Despite the obvious diversity in the morphology of the lateral system, it should be emphasized that the observed differences relate only to the macrostructure of this sensory formation. The actual receptor apparatus of the organ (a chain of neuromasts) is surprisingly the same in all fish, both morphologically and functionally.
The lateral line system responds to compression waves in the aquatic environment, flowing currents, chemical stimuli, and electromagnetic fields with the help of neuromasts - structures that combine several hair cells (Fig. 2.23).
Rice. 2.22. Fish lateral line channel
The neuromast consists of a mucous-gelatinous part - a capule, into which the hairs of sensitive cells are immersed. Closed neuromasts communicate with the external environment through small openings that perforate the scales.
Open neuromasts are characteristic of the canals of the lateral system that enter the head of the fish (see Fig. 2.23, a).
The canal neuromasts extend from head to tail along the sides of the body, usually in one row (fish of the family Hexagramidae have six or more rows). The term "lateral line" in everyday life refers specifically to the canal neuromasts. However, in fish, neuromasts have also been described that are separated from the canal part and look like independent organs.
Canal and free neuromasts located in different parts fish bodies and the labyrinth do not duplicate, but functionally complement each other. It is believed that the sacculus and lagena of the inner ear provide the sound sensitivity of fish from a great distance, and the lateral system makes it possible to localize the sound source (albeit already close to the sound source).
Rice. 2.23. The structure of the neuromastarfish: a - open; b - channel
It has been experimentally proven that the lateral line perceives low-frequency vibrations, both sound and those associated with the movement of other fish, i.e., low-frequency vibrations arising from the impact of a fish with its tail on the water are perceived by another fish as low-frequency sounds.
Thus, the sound background of the reservoir is quite diverse and the fish have a perfect system of organs for the perception of wave physical phenomena under water.
A noticeable effect on the activity of fish and the nature of their behavior is exerted by waves that occur on the surface of the water. The reasons for this physical phenomenon are many factors: the movement of large objects ( big fish, birds, animals), wind, tides, earthquakes. Excitement serves as an important channel for informing aquatic animals about events both in the reservoir itself and beyond. Moreover, the excitement of the reservoir is perceived by both pelagic and bottom fish. The reaction to surface waves from the side of the fish is of two types: the fish sinks to a greater depth or moves to another part of the reservoir. The stimulus acting on the body of the fish during the period of disturbance of the reservoir is the movement of water relative to the body of the fish. The movement of water during its agitation is detected by the acoustic-lateral system, and the sensitivity of the lateral line to waves is extremely high. Thus, for the occurrence of afferentation from the lateral line, it is sufficient to mix the cupula by 0.1 μm. At the same time, the fish is able to very accurately localize both the source of wave formation and the direction of wave propagation. The spatial diagram of fish sensitivity is species-specific (Fig. 2.26).
In the experiments, an artificial waveformer was used as a very strong stimulus. When its location changed, the fish unmistakably found the source of disturbance. The response to the wave source consists of two phases.
The first phase - the fading phase - is the result of an orienting reaction (an innate exploratory reflex). The duration of this phase is determined by many factors, the most significant of which are the height of the wave and the depth of the fish. For cyprinid fish (carp, crucian carp, roach) with a wave height of 2–12 mm and a dive of the fish by 20–140 mm, the orienting reflex took 200–250 ms.
The second phase - the phase of movement - a conditioned reflex reaction is developed in fish rather quickly. For intact fish, from two to six reinforcements are sufficient for its occurrence in blinded fish, after six combinations of wave formation of food reinforcement, a stable search food-producing reflex was developed.
Small pelagic plankton feeders are more sensitive to the surface wave, and large bottom fish are less sensitive. Thus, blinded heads with a wave height of only 1-3 mm already after the first presentation of the stimulus demonstrated orienting reaction. Marine bottom fish are characterized by sensitivity to strong waves on the surface of the sea. At a depth of 500 m, their lateral line is excited when the wave height reaches 3 m and a length of 100 m. As a rule, waves on the surface of the sea generate pitching. Therefore, not only the lateral line of the fish comes into excitation, but also its labyrinth. The results of experiments showed that the semicircular canals of the labyrinth respond to rotational movements, in which water currents involve the body of the fish. The utriculus senses the linear acceleration that occurs during the pitching process. During a storm, the behavior of both solitary and schooling fish changes. In light storms, pelagic species in coastal zone descend into the bottom layers. With strong waves, fish migrate to the open sea and go to great depths, where the effect of waves is less noticeable. It is obvious that strong excitement is estimated by fish as unfavorable or even dangerous factor. It suppresses feeding behavior and forces fish to migrate. Illogical changes in feeding behavior are also observed in fish species living in inland waters. Anglers know that when the sea is rough, the biting of the fish stops.
Thus, the reservoir in which the fish lives is a source of various information transmitted through several channels. Such awareness of fish about environmental fluctuations allows it to timely and adequately respond to them with locomotor reactions and changes in vegetative functions.
Fish signals. Obviously, the fish themselves are a source of various signals. They emit sounds in the frequency range from 20 Hz to 12 kHz, leave a chemical trace (pheromones, kairomones), have their own electric and hydrodynamic fields. Acoustic and hydrodynamic fields of fish are created in various ways.
The sounds made by fish are quite diverse, but due to low pressure they can be fixed only with the help of special highly sensitive equipment. Formation mechanism sound wave different fish species may be different (Table 2.5).
|
2.5. Sounds of fish and the mechanism of their reproduction |
Fish sounds are species-specific. In addition, the nature of the sound depends on the age of the fish and its physiological state. Sounds coming from a flock and from individual fish are also clearly distinguishable. For example, the sounds made by a bream resemble wheezing. The sound picture of a herring flock is associated with squeaking. The sea rooster of the Black Sea makes sounds reminiscent of the clucking of a chicken. A freshwater drummer identifies himself with a drum roll. Roach, loach, scale insects emit squeaks that are accessible to the naked ear.
While it is difficult to unequivocally characterize biological significance sounds made by fish. Some of them are background noise. Within populations, schools, as well as between sexual partners, sounds made by fish can also perform a communicative function.
Noise direction finding is successfully used in commercial fishing. The excess of the sound background of fish over ambient noise is no more than 15 dB. The background noise of a vessel can be ten times greater than a fishy soundscape. Therefore, the bearing of fish is possible only from those vessels that can operate in the "silence" mode, that is, with the engines turned off.
Thus, the well-known expression "dumb as a fish" is clearly not true. All fish have a perfect sound reception apparatus. In addition, fish are sources of acoustic and hydrodynamic fields, which they actively use to communicate within the flock, detect prey, and warn relatives about possible danger and other purposes.
- Read: Variety of fish: shape, size, color
Organ of balance and hearing
- Read more: Sense organs of fish
Cyclostomes and fish have a paired organ of balance and hearing, which is represented by the inner ear (or membranous labyrinth) and is located in the auditory capsules of the back of the skull. The membranous labyrinth consists of two sacs: 1) upper oval; 2) lower round.
In cartilage, the labyrinth is not completely divided into oval and round sacs. In many species, an outgrowth (lagen), which is the rudiment of a snail, departs from the round sac. Three semicircular canals depart from the oval sac in mutually perpendicular planes (in lampreys - 2, in hagfish - 1). At one end of the semicircular canals there is an extension (ampulla). The cavity of the labyrinth is filled with endolymph. The endolymphatic duct departs from the labyrinth, which in bony fish ends blindly, and in cartilaginous fish it communicates with the external environment. inner ear has hair cells, which are the endings of the auditory nerve and are located in sections in the ampullae of the semicircular canals, sacs and lagen. The membranous labyrinth contains auditory pebbles, or otoliths. They are located three on each side: one, the largest, otolith - in a round bag, the second - in an oval, the third - in the lagen. Annual rings are clearly visible on otoliths, by which age is determined in some fish species (smelt, ruff, etc.).
The upper part of the membranous labyrinth (an oval sac with semicircular canals) performs the function of an organ of balance, the lower part of the labyrinth perceives sounds. Any change in head position causes movement of the endolymph and otoliths and irritates the hair cells.
Fish perceive sounds in the water in the range from 5 Hz to 15 kHz, sounds of higher frequencies (ultrasounds) are not perceived by fish. Fish also perceive sounds with the help of the sensory organs of the lateral line system. The sensory cells of the inner ear and the lateral line have a similar structure, are innervated by the branches of the auditory nerve and belong to a single acoustic-lateral system (center in the medulla oblongata). The lateral line expands the wave range and allows you to perceive low-frequency sound vibrations (5–20 Hz) caused by earthquakes, waves, etc.
The sensitivity of the inner ear is increased in fish with a swim bladder, which is a resonator and reflector of sound vibrations. The connection of the swim bladder with the inner ear is carried out using the Weber apparatus (a system of 4 bones) (in cyprinids), blind outgrowths of the swim bladder (in herring, cod) or special air cavities. The most sensitive to sounds are fish that have a Weberian apparatus. With the help of a swim bladder connected to the inner ear, fish are able to perceive sounds of low and high frequencies.
N. V. ILMAST. INTRODUCTION TO ICHTHYOLOGY. Petrozavodsk, 2005
As is known, for a long time fish were considered deaf.
Once at home and abroad according to the method conditioned reflexes scientists conducted experiments (in particular, crucians, perches, tenches, ruffs and other freshwater fish were among the experimental subjects), it was convincingly proved that fish hear, the boundaries of the hearing organ were also determined, its physiological functions and physical parameters.
Hearing, along with vision, is the most important of the senses of remote (non-contact) action; with its help, fish navigate in the environment. Without knowledge of the properties of the hearing of fish, it is impossible to fully understand how the connection between individuals in a school is maintained, how fish relate to fishing gear, what is the relationship between predator and prey. Progressive bionics needs a wealth of accumulated facts on the structure and function of the hearing organ in fish.
Observant and savvy recreational fishermen have long benefited from the ability of some fish to hear noise. This is how the method of catching catfish on the “klok” was born. A frog is also used in the nozzle; trying to get free, the frog, raking its paws, creates a noise familiar to the catfish, which often turns out to be right there.
So the fish are listening. Let's look at their organ of hearing. Fish do not have what is called the external part of the organ of hearing or ears. Why?
At the beginning of this book, we mentioned physical properties water as an acoustic medium transparent to sound. How useful it would be for the inhabitants of the seas and lakes to be able to prick up their ears, like an elk or a lynx, in order to catch a distant rustle and timely detect a sneaking enemy. Yes, that's bad luck - it turns out that having ears is not economical for movement. Have you looked at pike? Her entire chiseled body is adapted for rapid acceleration and throw - nothing superfluous that would make movement difficult.
Fish also do not have the so-called middle ear, which is characteristic of terrestrial animals. In terrestrial animals, the middle ear apparatus plays the role of a miniature and simply arranged transceiver of sound vibrations, which performs its work through the tympanic membrane and auditory ossicles. These "details", which make up the structure of the middle ear of terrestrial animals, in fish have a different purpose, a different structure, a different name. And not by chance. The external and middle ear with its tympanic membrane is not biologically justified in conditions of large, rapidly increasing pressures of a dense mass of water with depth. It is interesting to note that in aquatic mammals - cetaceans, whose ancestors left the land and returned to the water, tympanic cavity has no outlet to the outside, since the outer ear canal either overgrown or blocked by an ear plug.
And yet, fish have an organ of hearing. Here is his scheme (see figure). Nature has taken care that this very fragile, subtly organized body was sufficiently protected - by this she, as it were, emphasized his importance. (And we have a particularly thick bone protecting the inner ear). Here is the maze 2
. The auditory ability of fish is associated with it (semicircular canals - balance analyzers). Pay attention to the departments marked with numbers 1
And 3
. These are lagena (lagena) and sacculus (sacculus) - auditory receivers, receptors that perceive sound waves. When, in one of the experiments, minnows with a developed food reflex to sound were removed from the lower part of the labyrinth - the sacculus and lagena - they stopped responding to signals.
Irritation through the auditory nerves is transmitted to the auditory center located in the brain, where the processes of transformation of the incoming signal into images and the formation of a response take place, which have not yet been comprehended.
There are two main types of auditory organs in fish: organs without connection to the swim bladder and organs integral part which is the swim bladder.
The swim bladder is connected to the inner ear with the help of the Weberian apparatus - four pairs of movably articulated bones. And although fish do not have a middle ear, some of them (cyprinids, catfish, characinids, electric eels) have its substitute - a swim bladder plus a Weber apparatus.
Until now, you knew that the swim bladder is a hydrostatic apparatus that regulates specific gravity body (as well as the fact that the bubble is an essential component of a full-fledged crucian fish soup). But it is not superfluous to know something more about this body. Namely: the swim bladder acts as a receiver and transducer of sounds (similar to our eardrum). The vibration of its walls is transmitted through the Weber apparatus and is perceived by the fish's ear as oscillations of a certain frequency and intensity. Acoustically speaking, a swim bladder is essentially the same as an air chamber placed in water; hence the important acoustic properties of the swim bladder. Due to the difference in the physical characteristics of water and air, the acoustic receiver
like a thin rubber pear or swim bladder, filled with air and placed in water, when connected to the diaphragm of the microphone, it sharply increases its sensitivity. The inner ear of the fish is the "microphone" that works in conjunction with the swim bladder. In practice, this means that although the separation of water and air reflects sounds to a large extent, fish are still sensitive to voices and noise from the surface.
The well-known bream is very sensitive during the spawning period and is afraid of the slightest noise. In the old days, during the spawning of bream, it was even forbidden to ring the bells.
The swim bladder not only increases the sensitivity of hearing, but also expands the perceived frequency range of sounds. Depending on how many times sound vibrations are repeated in 1 second, the sound frequency is measured: 1 vibration per second - 1 hertz. The ticking of a pocket watch can be heard in the frequency band from 1500 to 3000 hertz. For clear, intelligible speech on the telephone, a frequency range of 500 to 2000 hertz is sufficient. So we could talk on the phone with a minnow, because this fish reacts to sounds in the frequency range from 40 to 6000 hertz. But if guppies “approached” the phone, they would hear only those sounds that lie in the band up to 1200 hertz. Guppies don't have a swim bladder and their hearing aids can't pick up higher frequencies.
At the end of the last century, experimenters sometimes did not take into account the ability of various fish species to perceive sounds in a limited frequency range and made erroneous conclusions about the lack of hearing in fish.
At first glance, it may seem that the capabilities of the auditory organ of fish cannot be compared with extremely sensitive ear a person capable of detecting sounds of negligible intensity and distinguishing sounds whose frequencies lie in the range from 20 to 20,000 hertz. Nevertheless, the fish are perfectly oriented in their native element, and the sometimes limited frequency selectivity turns out to be expedient, because it makes it possible to single out only those sounds from the noise stream that are useful for the individual.
If the sound is characterized by any one frequency - we have a pure tone. A pure unadulterated tone is obtained using a tuning fork or a sound generator. Most of the sounds around us contain a mixture of frequencies, a combination of tones and tones.
A reliable sign of developed acute hearing is the ability to distinguish tones. The human ear is capable of distinguishing about half a million simple tones, varying in pitch and loudness. And what about the fish?
Minnows are able to distinguish sounds different frequency. Trained to a specific tone, they can remember and respond to that tone one to nine months after training. Some individuals can memorize up to five tones, for example, “do”, “re”, “mi”, “fa”, “sol”, and if the “food” tone during training was “re”, then the minnow is able to distinguish it from the neighboring one more low tone"do" and a higher tone "mi". Moreover, minnows in the frequency range of 400-800 hertz are able to distinguish sounds that differ in pitch by half a tone. Suffice it to say that the piano keyboard, which satisfies the most subtle human hearing, contains 12 semitones of an octave (a frequency ratio of two is called an octave in music). Well, perhaps the minnows are also "not deprived" of some musicality.
Compared to the "hearing" minnow, the macropod is not musical. However, the macropod also distinguishes two tones if they are separated from one another by 1 1/3 octaves. We can mention the eel, which is remarkable not only because it goes to spawn at distant seas, but also because it is able to distinguish sounds that differ in frequency by an octave. The foregoing about the acuity of hearing of fish and their ability to memorize tones makes us re-read the lines of the famous Austrian scuba diver G. Hass in a new way: “At least three hundred large silvery star-shaped horse mackerel swam up in a solid mass and began to circle around the loudspeaker. They kept a distance of about three meters from me and swam as if in a big round dance. It is likely that the sounds of the waltz - it was Johann Strauss' "Southern Roses" - had nothing to do with this scene, and only curiosity, at best. case sounds, attracted animals. But the impression of the fish waltz was so complete that I conveyed later in our film as I observed myself.
Now let's try to figure it out in more detail - what is the sensitivity of the hearing of fish?
We see two people talking in the distance, we see the facial expressions of each of them, gesticulation, but we do not hear their voices at all. The flow of sound energy flowing into the ear is so small that it does not cause an auditory sensation.
IN this case Hearing sensitivity can be measured by the smallest strength (loudness) of sound that the ear picks up. It is by no means the same over the entire range of frequencies perceived by a given individual.
The highest sensitivity to sounds in humans is observed in the frequency band from 1000 to 4000 hertz.
The brook chub in one of the experiments perceived the smallest sound at a frequency of 280 hertz. At a frequency of 2000 hertz, its auditory sensitivity was halved. In general, fish hear low sounds better.
Of course, hearing sensitivity is measured from some entry level taken as the sensitivity threshold. Since a sound wave of sufficient intensity produces quite perceptible pressure, it was agreed that the smallest threshold strength (or loudness) of sound should be determined in terms of the pressure it exerts. Such a unit is an acoustic bar. The normal human ear begins to pick up sound whose pressure exceeds 0.0002 bar. To understand how insignificant this is, let's explain that the sound of a pocket watch pressed to the ear exerts pressure on the eardrum that exceeds the threshold by 1000 times! In a very "quiet" room, the sound pressure level exceeds the threshold by 10 times. This means that our ear fixes the sound background, which we are sometimes consciously unable to appreciate. For comparison, note that the eardrum experiences pain when the pressure exceeds 1000 bar. We feel such a strong sound when standing near a starting jet aircraft.
We have given all these figures and examples of the sensitivity of human hearing only in order to compare them with the auditory sensitivity of fish. But it is no coincidence that they say that any comparison is lame. Water environment and structural features of the auditory organ of fish introduce noticeable corrections to the comparative measurements. However, under the conditions high blood pressure environment The sensitivity of human hearing is also markedly reduced. Be that as it may, but in a dwarf catfish, the sensitivity of hearing is no worse than human. This seems amazing, especially since the fish in the inner ear do not have the organ of Corti - the most sensitive, thinnest "device", which in humans is actually the organ of hearing.
All this is so: the fish hears the sound, the fish distinguishes one signal from another in frequency and intensity. But it should always be remembered that the hearing abilities of fish are not the same not only between species, but also among individuals of the same species. If we can still talk about some kind of “average” human ear, then in relation to the hearing of fish, any template is not applicable, because the peculiarities of the hearing of fish are the result of life in a specific environment. The question may arise: how does the fish find the source of the sound? It is not enough to hear the signal, you must orient yourself to it. It is vitally important for crucian carp, which has reached a formidable signal of danger - the sound of pike food excitement, to localize this sound.
Most of the studied fish are able to localize sounds in space at distances from sources approximately equal to the length of the sound wave; on long distances fish usually lose the ability to determine the direction to the source of the sound and make prowl, search movements, which can be deciphered as a “attention” signal. This specificity of the action of the localization mechanism is explained by the independent operation of two receivers in fish: the ear and the lateral line. The fish's ear often works in combination with the swim bladder and perceives sound vibrations in a wide range of frequencies. The lateral line records the pressure and mechanical displacements of water particles. No matter how small the mechanical displacements of water particles caused by sound pressure are, they must be sufficient to be noted by living "seismographs" - sensitive cells of the lateral line. Apparently, the fish receives information about the location of the low-frequency sound source in space from two indicators at once: the displacement value (lateral line) and the pressure value (ear). Special experiments were carried out to determine the ability of river perches to detect sources of underwater sounds emitted by a tape recorder and waterproofed dynamic headphones. The sounds of food recorded before were played into the water of the pool - the capture and grinding of food by perches. Such experiments in an aquarium are greatly complicated by the fact that the repeated echo from the walls of the pool, as it were, smears and drowns out the main sound. A similar effect is observed in a large room with a low vaulted ceiling. Nevertheless, perches have shown the ability to direct, from a distance of up to two meters, to detect the source of sound.
The method of food conditioned reflexes helped to establish under aquarium conditions that crucians and carps are also able to determine the direction to the sound source. Some sea fish(mackerel, rulen, red mullet) in experiments in an aquarium and in the sea, they found the location of the sound source from a distance of 4-7 meters.
But the conditions under which the experiment is set up to determine this or that acoustic ability of fish do not yet give an idea of how sound signaling is carried out in fish in a natural setting, where the surrounding background noise is high. Sound signal carrying useful information, only then it makes sense when it reaches the receiver in an undistorted form, and this circumstance does not require special explanation.
In experimental fish, including roach and perch, kept in small flocks in an aquarium, a conditioned food reflex was developed. As you have noticed, the food reflex appears in many experiments. The fact is that the feeding reflex is quickly developed in fish, and it is the most stable. Aquarists know this well. Which of them did not do a simple experiment: feeding the fish with a portion of bloodworms, while tapping on the glass of the aquarium. After several repetitions, having heard a familiar knock, the fish rush together “to the table” - they have developed a feeding reflex to the conditioned signal.
In the above experiment, two types of conditioned food signals were given: a single-tone sound signal with a frequency of 500 hertz, rhythmically emitted through an earpiece by means of a sound generator, and a noise “bouquet” consisting of sounds pre-recorded on a tape recorder that occur during feeding of individuals. To create noise interference, a trickle of water was poured into the aquarium from a height. In the background noise it created, as measurements showed, all frequencies of the sound spectrum were present. It was necessary to find out whether the fish are able to isolate the food signal and react to it under camouflage conditions.
It turned out that fish are able to isolate signals that are useful to them from noise. Moreover, the monotonous sound given rhythmically was clearly recognized by the fish even when a trickle of falling water “clogged” it.
Sounds of a noise nature (rustles, champing, rustling, murmuring, hissing, etc.) are emitted by fish (like a person) only in cases where they exceed the level of surrounding noise.
This and other similar experiments prove the ability of fish hearing to distinguish vital signals from a set of sounds and noises that are useless for an individual of this species and are abundantly present in vivo in any body of water in which there is life.
Over several pages, we have looked at the possibilities of hearing in fish. Aquarium lovers, with simple and affordable devices, which we will discuss in the corresponding chapter, could independently perform some simple experiments: for example, determining the ability of fish to focus on a sound source when it has biological significance for them, or the ability of fish to distinguish such sounds against the background of other “useless” noises, or the detection of the hearing limit in a particular type of fish, etc.
Much is still unknown, much needs to be understood in the structure and operation of the auditory apparatus of fish.
The sounds made by cod and herring have been well studied, but their hearing has not been studied; other fish are just the opposite. The acoustic capabilities of representatives of the goby family have been studied more fully. So, one of them, a black goby, perceives sounds that do not exceed a frequency of 800-900 hertz. Everything that goes beyond this frequency barrier does not “touch” the bull. Its auditory capabilities allow it to perceive the hoarse, low-pitched grunts emitted by an opponent through the swim bladder; it's grumbling in certain situation can be interpreted as a threat signal. But the high-frequency components of the sounds that arise when the gobies feed are not perceived by them. And it turns out that for some cunning bull, if he wants to feast on prey alone, the direct calculation is to eat on slightly higher tones - fellow tribesmen (they are competitors) will not hear him and will not find him. This is of course a joke. But in the process of evolution, the most unexpected adaptations were developed, generated by the need to live in a community and depend on a predator from its prey, a weak individual from its stronger competitor, etc. vision, etc.) turned out to be a boon for the species.
In the next chapter, we will show that sound signals in the life of the fish kingdom have such great importance, which until recently was not suspected.
Water is the keeper of sounds .........................................................................................
9
How do fish hear?
...........................................................................................................
17
Language without words is the language of emotions...........................................................................................
29
"Silent" among the fish? ................................................. ................................................. ...... 35
Fish "Esperanto" .............................................. ................................................. ............. 37
Cool bite! ................................................. ................................................. .................... 43
Do not flutter: sharks are close! ................................................. ......................................... 48
About the "voices" of fish and what is meant by this
and what comes out of it............................................................... ................................................. .......... 52
Fish signals associated with reproduction .............................................. ........................... 55
"Voices" of fish in defense and attack.................................................................. ................................. 64
Baron's Undeservedly Forgotten Discovery
Munchausen .................................................................. ................................................. ................... 74
"Table of Ranks" in a flock of fish .............................................. ................................................. ..77
Acoustic milestones on migration routes .............................................................. ................................. 80
Swim bladder improves
seismograph................................................. ................................................. ......................... 84
Acoustic or electrical? ................................................. ................................................. 88
On the practical benefits of studying fish "voices"
and hearing...................................................................................................................................
97
“Excuse me, can you be more gentle with us ..?” ................................................. ................97
The fishermen wised up the scientists; scientists go further .............................................................. .............. 104
Reporting from the depths of the joint .............................................. ................................................. ..... 115
Acoustic mines and demolition fish .............................................................. ........................... 120
Bioacoustics of fish in the reserve of bionics .............................................. ................................... 124
Amateur underwater hunter
sounds ..................................................................................................................................
129
Recommended Reading .................................................................. ................................................. 143
