Do fish see water? Can the fish see the angler? The world that is located above the water

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.

Surprisingly, 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 able to perceive 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.

When going fishing, every angler asks himself a number of questions: where to go? what tackle should I take? Which attachment should I use? On a reservoir, additional questions arise: where to fish - at depth or near the shore? in still water or on the current? from the bottom, on top or in mid-water? All these questions are significant. After all, the success of fishing depends on their correct decision. But finding such a solution is not always easy. The decisive point is direct study of a reservoir and the fish living in it. In this case, conversations with local fishermen can be used, but the main thing, of course, is personal observations.

BODY STRUCTURE OF FISHES AND THEIR MOVEMENT

Fish need to move to find food and escape from enemies. However, water provides significant resistance to their movement. Therefore, in the process of evolution, most fish acquired a streamlined body shape, making it easier to overcome the resistance of the aquatic environment. The most perfect streamlined body shape is found in migratory fish that make long migrations, such as salmon. Almost the same ridged or spindle-shaped body, powerful tail and medium-sized scales are found in fish that constantly live in the rapids (trout, minnow, osman, barbel, etc.). Sometimes some fish (roach, ide) that live in the upper reaches of a river in a fast current have a more ridged body than fish of the same species that inhabit the mouth, where the current is slower. Wide, tall-bodied fish live in calm waters, since here they do not have to fight the current; In addition, this body shape helps them better avoid predators who are less willing to grab wide fish.

The body shapes of fish that live at the bottom and in the upper layers of water are also different. For example, bottom fish (flounder, catfish, burbot, goby) have a flattened body, allowing them to rest on the ground with a large surface.

In cases where fish hardly move, part of their body, together with the tail, turns into an attachment organ (seahorse).

The nature of nutrition also has a known influence on body shape; for example, in predatory fish that catch up with prey, the body is usually more slender than in fish that feed on sedentary food.

The mechanism of fish movement remained unclear for a long time. It was assumed that the fins play the main role here. Recent studies by physicists and ichthyologists have proven that the forward movement of fish is carried out mainly by wave-like bends of the body. The caudal fin provides some assistance in moving forward. The role of other fins is reduced mainly to coordinating and guiding functions - the dorsal and anal fins serve as a keel, the pectoral and abdominal fins make it easier for the fish to move vertically and help to turn in the horizontal plane.

BREATH

Most fish breathe oxygen dissolved in water. The main respiratory organ is the gills. The shape and size of the surface of the gills, the structure of the gill slits and the mechanism of respiratory movements depend on the lifestyle of the fish. Fish that swim in mid-water have large gill slits, and the gill filaments are constantly washed by fresh water rich in oxygen. In bottom fish - eel, flounder - the gill slits are small (otherwise they may become clogged with silt) with devices for forced circulation of water.

Fish that live in oxygen-poor water have additional respiratory organs. When there is a lack of oxygen in the water, crucian carp and some other fish swallow atmospheric air and use it to enrich the water with oxygen.

Tench, catfish and eel have additional cutaneous respiration. The swim bladder is involved in the respiratory functions of the perch, while the intestines of the loach are involved. Some warm-water fish are endowed with organs that allow them to breathe directly with atmospheric air. In some fish it is a special labyrinth apparatus, in others it is a swim bladder that has turned into a respiratory organ.

In accordance with the structure of the respiratory organs, fish have different attitudes towards the amount of oxygen dissolved in water. Some fish need a very high content of it in water - salmon, whitefish, trout, pike perch; others are less demanding - roach, perch, pike; Still others are satisfied with a completely insignificant amount of oxygen - crucian carp, tench. There is, as it were, a certain threshold for the oxygen content in water for each species of fish, below which individuals of a given species become lethargic, almost do not move, feed poorly and ultimately die.

Oxygen enters water from the atmosphere and is released by aquatic plants, the latter, on the one hand, releasing it under the influence of light, and on the other, absorbing it in the dark and expending it during decay. Therefore, “the positive role of plants in the oxygen regime is noticeable only during the period of their growth, that is, in the summer, and, moreover, during the day.

Oxygen slowly penetrates from one water layer to another, and there is always more of it in the surface layers than near the bottom. This is one of the reasons for the weak development of life and the lack of accumulation of fish in the summer at depths, especially in stagnant reservoirs.

Lakes have areas with higher and lower oxygen concentrations. For example, the wind blowing from the shore drives away the oxygen-rich upper layers of water, and in their place comes deep water that is poorly saturated with oxygen. Thus, near the quiet shore, a zone poorer in oxygen content is created, and the fish, all other things being equal, prefers to stay near the surf shore. A typical example is the behavior of the oxygen-loving grayling in Lake Ladoga, which approaches the shore mainly when there is a steady wind blowing from the lake.

The oxygen regime deteriorates sharply in stagnant reservoirs in winter, when ice cover prevents air from accessing the water. This is especially noticeable in shallow, heavily overgrown reservoirs with a muddy or peaty bottom, where the oxygen supply is spent on the oxidation of various organic residues. In winter, zones with unequal oxygen content are found in lakes even more often than in summer.

Areas with a rocky or sandy bottom, at the outlet of spring waters, at the confluence of streams and rivers, are richer in oxygen. These places are usually chosen by fish for winter stopovers. In some lakes, especially during severe winters, the oxygen content in the water drops so much that mass fish deaths occur—the so-called fish kills.

In rivers, especially fast-flowing ones, there is no sharp natural lack of oxygen observed either in summer or winter. However, in rivers clogged with timber rafting waste and polluted by industrial wastewater, this deficiency can be so great that oxygen-demanding fish completely disappear.

SENSE ORGANS

VISION

The organ of vision - the eye - in its structure resembles a photographic apparatus, and the lens of the eye is similar to a lens, and the retina is similar to the film on which the image is obtained. In terrestrial animals, the lens is lenticular in shape and is capable of changing its curvature, so animals can adapt their vision to distance. The lens of fish is spherical and cannot change shape. Their vision is adjusted to different distances as the lens approaches or moves away from the retina.

The optical properties of the aquatic environment do not allow the fish to see far. Practically, the limit of visibility for fish in clear water is considered to be a distance of 10-12 m, and fish can see clearly no further than 1.5 m. Diurnal predatory fish living in clear water (trout, grayling, asp, pike) see better. Some fish see in the dark (pike perch, bream, catfish, eel, burbot). They have special light-sensitive elements in their retina that can perceive weak light rays.

The angle of view of fish is very large. Without turning their bodies, most fish are able to see objects with each eye in a zone of about 150° vertically and up to 170° horizontally.

Otherwise, the fish sees objects above the water. In this case, the laws of refraction of light rays come into force, and the fish can see without distortion only objects that are directly overhead - at the zenith. Obliquely incident light rays are refracted and compressed into an angle of 97°.6 (Fig. 2). The sharper the angle of entry of the light beam into the water and the lower the object, the more distorted the fish sees it. When the light beam falls at an angle of 5-10°, especially if the water surface is rough, the fish stops seeing the object.

The rays coming from the eye of the fish outside the cone are completely reflected from the water surface, so it appears to the fish as mirror-like.

On the other hand, the refraction of rays allows the fish to see seemingly hidden objects. Let's imagine a body of water with a steep, steep bank. Outside the refraction of rays, a person can see a person on the water surface.

Pisces distinguish colors and even shades.

Color vision in fish is confirmed by their ability to change color depending on the color of the ground (mimicry). It is known that perch, roach, and pike, which stay on a light sandy bottom, have a light color, and on a black peat bottom they are darker. Mimicry is especially pronounced in various flounders, capable of adapting their color to the color of the ground with amazing accuracy. If a flounder is placed in a glass aquarium with a chessboard placed under the bottom, then chess-like cells will appear on its back. Under natural conditions, a flounder lying on a pebble bottom blends so well with it that it becomes completely invisible to the human eye. At the same time, blinded fish, including flounder, do not change their color and remain dark-colored. From this it is clear that the change in color by fish is associated with their visual perception.

Experiments of feeding fish from multi-colored cups confirmed that fish clearly perceive all spectral colors and can distinguish similar shades. The latest experiments based on spectrophotometric methods have shown that many species of fish perceive individual shades no worse than humans.

Using food training methods, it has been established that fish also perceive the shape of objects - they distinguish a triangle from a square, a cube from a pyramid.

Of particular interest is the attitude of fish to artificial light. Even in pre-revolutionary literature they wrote that a fire built on the river bank attracts roaches, burbot, catfish and improves fishing results. Recent studies have shown that many fish - sprat, mullet, syrty, saury - are directed to sources of underwater lighting, so electric light is currently used in commercial fishing. In particular, this method is used to successfully catch sprat in the Caspian Sea, and saury near the Kuril Islands.

Attempts to use electric light in sport fishing have not yet yielded positive results. Such experiments were carried out in winter in places where perch and roach accumulated. They cut a hole in the ice and lowered an electric lamp with a reflector to the bottom of the reservoir. Then they fished with a jig and added bloodworms in a neighboring hole and in a hole cut away from the light source. It turned out that the number of bites near the lamp is less than away from it. Similar experiments were carried out when catching pike perch and burbot at night; they also did not have a positive effect.

For sport fishing, it is tempting to use baits coated with luminous compounds. It has been established that fish grab luminous baits. However, the experience of Leningrad fishermen did not show their advantages; In all cases, fish take regular bait more readily. The literature on this issue is also not convincing. It describes only cases of catching fish with luminous baits, and does not provide comparative data on fishing under the same conditions with ordinary baits.

The visual characteristics of fish allow us to draw some conclusions that are useful for the fisherman. It is safe to say that a fish located at the surface of the water is not able to see a fisherman standing on the shore further than 8-10 m and sitting or wading - further than 5-6 m; The transparency of the water also matters. In practice, we can assume that if an angler does not see a fish in the water when he looks at a well-lit water surface at an angle close to 90°, then the fish does not see the angler. Therefore, camouflage makes sense only when fishing in shallow places or on top in clear water and when casting over a short distance. On the contrary, items of fishing equipment that are close to the fish (lead, sinker, net, float, boat) should blend into the surrounding background.

HEARING

The presence of hearing in fish was denied for a long time. Facts such as fish approaching the feeding place when called, attracting catfish by hitting the water with a special wooden mallet (“knocking” catfish), and reacting to the whistle of a steamboat have not yet proved much. The occurrence of the reaction could be explained by irritation of other sense organs. Recent experiments have shown that fish respond to sound stimuli, and these stimuli are perceived by the auditory labyrinths in the fish’s head, the surface of the skin, and the swim bladder, which plays the role of a resonator.

The sensitivity of sound perception in fish has not been established exactly, but it has been proven that they pick up sounds worse than humans, and fish hear high tones better than low ones. Fish hear sounds arising in the aquatic environment at a considerable distance, but sounds arising in the air are poorly heard, since sound waves are reflected from the surface and do not penetrate well into the water. Given these features, the angler should be wary of making noise in the water, but does not have to worry about spooking the fish by talking loudly. The use of sounds in sport fishing is interesting. However, the question of which sounds attract fish and which repels them has not been studied. So far, sound is used only when catching catfish, by “closing.”

Lateral line organ

The lateral line organ is present only in fish and amphibians that constantly live in water. The lateral line is most often a canal that stretches along the body from head to tail. Nerve endings branch out in the canal, perceiving even the most insignificant water vibrations with great sensitivity. With the help of this organ, fish determine the direction and strength of the current, feel the currents of water formed when underwater objects are washed away, feel the movement of a neighbor in the school, enemies or prey, and disturbances on the surface of the water. In addition, the fish also perceives vibrations that are transmitted to the water from the outside - soil shaking, impacts on the boat, blast waves, vibration of the ship's hull, etc.

The role of the lateral line in the fish's grasping of prey has been studied in detail. Repeated experiments have shown that a blinded pike is well oriented and accurately grabs a moving fish, not paying attention to a stationary one. A blind pike with a destroyed lateral line loses the ability to orient itself, bumps into the walls of the pool and... being hungry, she does not pay attention to the swimming fish.

With this in mind, anglers must be careful both on the shore and in the boat. Shaking the soil under your feet, a wave from careless movement in the boat can alert the fish and scare it away for a long time. The nature of the movement of artificial baits in the water is not indifferent to the success of fishing, since predators, when pursuing and seizing prey, feel the water vibrations created by it. Of course, those baits that most fully reproduce the characteristics of the usual prey of predators will be more catchy.

Organs of smell and taste

The organs of smell and taste in fish are separated. The organ of smell in bony fishes is paired nostrils, located on both sides of the head and leading into the nasal cavity, lined with olfactory epithelium. Water enters one hole and leaves the other. This arrangement of the olfactory organs allows the fish to sense the odors of substances dissolved or suspended in water, and during the current the fish can only smell the stream carrying the odorous substance, and in calm waters - only in the presence of water currents.

The olfactory organ is least developed in diurnal predatory fish (pike, asp, perch), and stronger in nocturnal and crepuscular fish (eel, catfish, carp, tench).

The taste organs are located mainly in the mouth and pharyngeal cavity; In some fish, taste buds are located in the area of ​​the lips and whiskers (catfish, burbot), and sometimes located throughout the body (carp). As experiments show, fish are able to distinguish between sweet, sour, bitter and salty. Just like the sense of smell, the sense of taste is more developed in nocturnal fish.

INFLUENCE OF WATER TEMPERATURE AND PRESSURE ON FISH

Fish belong to animals that have a variable body temperature. It changes along with changes in ambient temperature and is only a few tenths of a degree higher. Only tuna can have a body temperature that exceeds the temperature of their surrounding aquatic environment by 8-9° C. Therefore, a sharp change in temperature (for example, transferring fish from one pool to another with a temperature difference of 4-5°) causes their illness and often death. Fish can tolerate a gradual rise or fall in temperature without any special consequences.

On the Chukotka Peninsula, dalia fish live in streams and shallow lakes, which freezes when water bodies freeze and comes to life when they thaw. But this, of course, is an isolated example; usually fish cannot tolerate such wide temperature fluctuations.

Temperature has a great influence on the vital functions of fish. Each species exhibits the greatest vital activity in a certain temperature range. For example, optimal nutrition for trout is observed at 10-12°, for pike at 15-16°, for carp at 23-28°. Above and below a certain temperature, fish stop feeding altogether. Trout do not feed if the water temperature is below 3° and above 18°. Burbot does not feed at water temperatures above 12°. Carp begins to feed no earlier than the water temperature reaches 10°, etc. The given figures cannot be considered unchanged: there are deviations associated with the adaptation of fish to local climatic conditions.

Fish reproduction is closely related to water temperature. As the temperature rises in the water, algae, higher aquatic plants, and various animal organisms develop and better conditions are created for the nutrition and growth of fish. Sometimes an increase in water temperature can also have an adverse effect (for example, worsen the oxygen regime of a reservoir).

The fall in temperature in autumn forces most fish to change their lifestyle and move to deeper places where the water temperature is more constant. In winter, the life processes of heat-loving fish freeze. The fish migrate to the depths, almost stop moving, stop feeding and seem to hibernate. Only burbot, trout, and salmon remain almost completely active in winter. Perch, roach, ruffe, pike continue to feed partially, and, less commonly, pike perch and bream.

Water temperature has a decisive influence on fish distribution; For each species there are northern and southern distribution boundaries. For example, carp stays mainly only in the lower reaches of southern rivers; The barbel rarely rises along the Dnieper above Dorogobuzh; pike perch, widespread within the Leningrad region, is completely absent in the White Sea basin. In marine and oceanic reservoirs, isotherms are often the boundaries of the distribution of a particular species of fish.

It is not entirely clear how changes in atmospheric pressure affect fish behavior. Some anglers believe that fish are best caught when the atmospheric pressure decreases, others say that when the atmospheric pressure increases. Most believe that a gradual change in pressure does not affect the fish’s bite; only sharp changes in the barometer have a harmful effect.

There is a point of view that changes in atmospheric pressure do not affect fish at all. This is motivated by the fact that fish, even with a slight vertical movement in the water column, experiences much greater changes in pressure than during the most dramatic barometric jumps. Indeed, when the atmospheric pressure changes by 50 millibars (a very sharp jump in the barometer), it is enough for the fish to correspondingly rise or fall by 0.5 m in order not to feel such a “jump” at all.

It is difficult to say which opinion is correct, as there is no reliable data for this yet.

NUTRITION

Some bluefish, some whitefish, sabrefish, bleak, as well as juveniles of most fish feed on plankton - small organisms that live in the water column. Others - bream, carp, silver bream, ruff, gudgeon - look for food at the bottom of reservoirs; in the mud they find insect larvae, worms, mollusks, organic remains and are said to feed on benthos. Some fish - roach, rudd, podust - feed mainly on plant foods. A number of fish - catfish, salmon, pike, pike perch, perch - eat other fish, which is why they are called predatory. Insects falling into the water play a leading role in the nutrition of fish such as trout, grayling, and dace.

The composition of food changes with the age of the fish, which is associated with changes in its organs. The diet of the Caspian roach - roach - changes especially dramatically: at the earliest stages of development, the roach feeds on plant plankton, later on animals, then switches to feeding on insect larvae, and at an older age it eats almost exclusively mollusks.

The entire fish body is adapted to feeding on one food or another, from the sense organs to the digestive tract.

Of the sense organs, fish that feed on benthos have the most well-developed sense of smell and taste, while insectivores have vision, and carnivores also have a lateral line that helps to detect the movement of prey.

The structure of the mouth of fish is also different. Fish that feed on plankton usually have large mouths and elongated gill rakers that help siphon out small organisms. Benthic-eating fish have a mobile, suction mouth; in bream, for example, it extends into a tube. Carnivores usually have teeth in their mouths that help them grasp and hold prey. In carp fish, teeth are placed in the pharynx and are used to grind food.

The shape of teeth in fish is varied and is one of the signs when determining the species.

Some predators, in particular pike, periodically change their teeth. They are replaced gradually, as they wear out, and for each individual at different times. Therefore, the widespread opinion among fishermen that all pikes are not taken due to the change of teeth in a certain period is unfounded.

The digestive organs of fish are also different. Predators have a stomach, but peaceful animals do not have a stomach and food is digested in the intestines, which are longer, the more plant substances are contained in the usual composition of the food.

The duration of food digestion varies among fish. Predatory fish, which swallow their prey whole, take the longest to digest it. Digestion of food in pike, perch, and pike perch, with a normal filling of the stomach and normal external conditions, lasts about three days.

Therefore, they eat with long breaks. Peaceful fish digest food in a few hours and can feed almost continuously.

The feeding intensity of fish depends on the state of their body and environmental conditions.

In most fish species, spawning changes have a significant impact on food intake. Before spawning, the so-called pre-spawning glutton is observed; it stops during spawning, and after spawning it resumes with particular intensity. There are exceptions to this general rule. For example, salmon that enter the river to spawn sometimes do not feed for about a year, i.e., during the entire spawning period. Chub, ide, grayling, and perch feed during spawning, but burbot and pike perch only after it ends. In pike, bream, and carp, there is a long period (about two weeks) between the end of spawning and the beginning of feeding.

The behavior of fish can change in different bodies of water. Thus, the asp living in Vuoksa has a pre-spawning zhor, while in Volkhov, Meta, and Dnieper such asp zhor is not known. The migratory bream in most rivers has a zhor, but the local bream does not. In some rivers, pike perch, roach, and carp are not taken before spawning, and in the Neva - pike.

Environmental conditions such as water temperature and oxygen content in it, as discussed above, have an even greater impact on fish nutrition. The intensity of feeding and, consequently, the fish’s bite largely depend on these conditions.

INFLUENCE OF WIND AND OTHER FACTORS ON FISH

Wind has a great influence on fish nutrition and their bite. Northern and eastern winds are unfavorable for fishing, and fish take better with a western or southern wind.

When the wind changes, the air temperature usually changes. Northern and northeastern winds in our hemisphere usually cause cooling. A decrease in air temperature leads to cooling of water in reservoirs, and this can have different effects on the behavior and bite of fish.

It is known that Each species of fish feeds most intensively in a certain temperature range. Let's assume that the water temperature in the reservoir was 15°. A north wind blew, it became colder, and the water temperature dropped to 10°. Then the trout bite will improve, but the perch and pike bite will worsen. Cold weather will have a particularly adverse effect on heat-loving fish - crucian carp, carp, tench, and carp. On the contrary, cold-loving burbot and palya, which did not feed at all before the cold snap, can come out from the depths to shallower places and take the bait.

With southern winds, warm weather usually sets in, and warming will most likely lead to a weakening of the bite of cold-loving fish and a revival of the bite of heat-loving fish.

Winds from the west and east in different geographical locations can cause different changes in temperature and for this reason have different effects on the behavior of fish.

Winds not only change air temperature, but also affect precipitation. In early spring and late autumn, the best catches are usually observed on sunny days. At the height of summer when the weather is clear, on the contrary, a revival in the bite can be more likely to be expected on rainy, cloudy days. Consequently, the fisherman must take into account what kind of weather in a given area the winds blowing from the west or east, north or south promise.

Sometimes changes in the bite occur before any changes occur in the environment surrounding the fish, as if the fish are anticipating them. It is explainable. Fish could have developed a reflex to changes in the direction of movement of waves, surface currents, and wind direction, which entailed changes in the placement of food objects.

However, there may also be a simple coincidence with the feeding rhythms of fish.

Often the wind can affect the behavior and bite of fish, regardless of whether it blows from the north, south, etc.

In summer, some reservoirs lack oxygen in the water. The wind, as mentioned above, helps to mix different layers of water, and the oxygen content in the water increases. It is obvious that in the hot season in reservoirs suffering from a lack of oxygen, after winds of any direction, the bite improves.

In some areas of the reservoir, the wind can create an unfavorable oxygen regime. Let’s assume that during a “blooming” of water, the wind will blow a lot of algae into some backwater. At first, this will not affect the oxygen content, but as soon as the algae begin to die and consume oxygen for decay, its amount in the backwater will sharply decrease. The fish will leave the backwater, and where there was recently a magnificent bite, you may not wait for a single bite.

If the bottom of the surf shore is muddy, then the wave washes out the larvae of various insects from the mud, which attract bream, carp and many other fish. If the bottom near the shore is rocky or sandy, and also devoid of aquatic vegetation, then it is difficult for small fish to stay here; it goes to quiet places, and therefore predators will not accumulate near the surf shore.

In lakes, the wind creates different currents. They change with changes in its strength and direction. Studying the direction of emerging currents is especially important when fishing on rocky or sandy shallows far from the shore. The fish here accumulate at the boundary between shallows and depths, standing against the current with their heads towards the shallows.

When searching for such places, one must keep in mind that the current in the bottom layer can be directed at any angle to the upper layer. It depends on the bottom topography, the location of the shores and islands. Bottom currents persist even in complete calm due to the return of water masses previously driven by the wind. Particularly strong currents arise in the channels between lakes and between islands; here the best bite is observed at the moments of the strongest water movement.

The movement of fish in lakes from the depths to the shores and back is often associated with the direction of the current. As is known, fish move more willingly against the current, and the approach of bottom fish to the shore can be more likely to be expected with a wind blowing from the lake, and the approach of those living in the upper layers of water - with a coastal one.

Interesting migrations of pike perch and catfish are observed in the arms of the Azov Sea. When the wind blows from the sea, salt water enters the river, and with it the pike perch rises and begins to be caught well on fishing rods. Catfish avoid sea water and, when the water in the channels becomes brackish, goes into the estuary. If the wind blows from the estuary, then the water in the channel becomes fresh, the pike perch returns to the sea, and the catfish enters the channel.

Currents arising from winds can change the water temperature in certain areas of the reservoir and cause a concentration of fish where it would seem impossible to expect.

On rivers, the wind blowing with the current is not conducive to fishing, while the wind blowing against the current provides a good bite. This indication is hardly correct: rivers usually have many bends, and in different sections the wind will blow from the shore, then downstream, then up.

In which areas it is better to fish depends on the type of fish, the type of its food and the way of life in a given body of water. For example, in the summer it is more advisable to look for chub, trout, and grayling near the leeward shore: the wind blows away many insects from the trees and bushes growing on the shore, and the fish willingly gather in such places.

Juvenile fish find shelter near the quiet shore, and where there are a lot of small things, predators can be expected.

It happens that a breaking wave erodes the base of clayey ravines, washing away the mayfly larvae that live here, so on windy days fish come here.

At the mouths of large rivers, wind blowing against the current causes the water to rise and weaken the current. This facilitates the entry of perch, pike perch, and bream into the river. Winds and rain can cause significant gains or losses of water. This affects the bite and behavior of fish in different ways.

If the water level causes significant turbidity, the bite usually worsens, since solid particles suspended in the water clog the gills and make it difficult for the fish to breathe. In addition, in turbid water it is more difficult for fish to detect the bait. On the contrary, the rise and turbidity of the water in a river flowing into a large river with clean water attracts fish (ide, bream and others) to the mouth of this river, which intensifies the bite.

If the profit of water is not associated with its turbidity, then the results of fishing depend on the nature of the banks and the size of the spill. A large spill is not conducive to fishing: the fish scatter widely throughout the newly flooded areas and it is much more difficult to detect their accumulation. And the amount of food in the spill increases, so the fish are less interested in the bait. The rise of water in a river flowing on steep banks does little to change the feeding conditions and fish bite.

The loss of water negatively affects fishing only in the first period; but as soon as its level is established, the fish gather in new places, and normal biting resumes. Reducing food and places suitable for habitat leads to concentration of fish, and this increases fishing results. Some fishermen believe that the behavior of fish is greatly influenced by the change in lunar phases, and in one area they believe that fish are best caught during the new moon, in another - during the full moon, and in a third - during the phases in which fish spawn.

Abroad, it is believed that the relative position of the moon and the sun has a great influence on the bite of fish. The American fisherman I. Knight compiled tables by which it is supposedly possible to determine on which day the fish will be caught well and on which - poorly.

Similar tables are common in Scandinavian countries, in particular in Finland. According to Finnish data, fish will be best caught during the hours of the highest moon.

It is known that the gravity of the moon causes ebbs and flows in the oceans and seas, so there the phases of the moon can undoubtedly have a great influence on the behavior of fish. There are special tidal currents, and the tidal wave washes out the animals on which fish feed from the coastal soil.

In inland waters, the change in lunar phases does not cause such significant changes in the environment surrounding fish, and therefore it is difficult to assume that the phases of the moon affect their behavior, including biting.

The tables compiled abroad do not take into account the main thing - the type of fish, and every fisherman knows that the time of active feeding is not the same for different fish. For example, two to three weeks after spawning, the pike does not feed at all, and at this time the ide can very actively grab the bait offered by the fisherman; in mid-summer the best time for catching asp comes, but you can’t catch burbot when the water is warm, etc.

Thunderstorms do not seem to have much effect on the fish. The exception is close thunderstorm strikes, which can scare away the fish for a short time.

In conclusion, it should be said that there is still much that remains unclear regarding the impact of changes in the atmosphere on the behavior and bite of fish. Here, further observations by sports fishermen should play a major role.

INSTINCT AND EXPERIENCE

Some fishermen attribute exceptional intelligence to fish, telling “hunting” stories about pikes and ides opening the lids of cages, about bream rising through the forest to the surface of the water so that, once convinced of the presence of an angler, they disappear into the depths, about “smart” carp, knocking down with their tail bait from the hook and only after that feast on it; about “cunning” perches driving away their less intelligent comrades from a hook with a nozzle, etc.

Of course, most of these stories are a figment of the imagination of those telling them, but there are examples that seem to confirm the presence of “smartness” in fish. Don’t the long journeys of salmon, whitefish, and eels in search of favorable spawning places seem smart? Or the protection of offspring observed in stickleback, catfish and some other fish? Or the method of obtaining food used by the tropical spray fish, which, releasing a stream of water from its mouth, knocks insects from the trees surrounding the pond and grabs them as they fall? The behavior of the fish, clearly wary of thick and rough forests, also seems intelligent.

Academician I.P. Pavlov believes that fish, like land animals, have two types of activity that seem to replace reason: based on individual experience and instinctive, passed on from generation to generation. These two types of activity explain the actions of fish that seem smart to us.

Spawning migrations, protection of offspring, one or another method of obtaining food are instinctive actions developed in fish in the process of adaptation to changing living conditions. The suspicious attitude of fish towards unfamiliar objects or towards familiar objects that behave unusually is explained by the instinctive caution of fish, developed due to the need to constantly fear enemies, as well as personal experience acquired by this individual.

The role of skills in the actions of fish is clearly illustrated by the following example. The aquarium with the pike in it was partitioned with glass and a live fish was allowed into the fenced off part. The pike immediately rushed towards the fish, but after hitting the glass several times, it stopped its unsuccessful attempts. When the glass was taken out, the pike, taught by “bitter” experience, no longer renewed attempts to grab the fish. In the same way, a fish that has been hooked or grabbed an inedible spoon takes the bait much more carefully. Therefore, in remote reservoirs, where fish are unfamiliar with people and fishing rods, they are less careful than in reservoirs frequently visited by fishermen.

In order for a fish to become wary of rough tackle, it does not have to be hooked itself. Sharp throws of one frightened, hooked fish can frighten and alert the entire flock for a long time, causing a suspicious attitude towards the proposed bait.

Sometimes fish use the experience acquired by their neighbor. In this regard, the behavior of a school of bream surrounded by a seine is characteristic. First, finding themselves in the tone, the bream rush in all directions; but as soon as one of them, taking advantage of the unevenness of the bottom, slips under the bowstring, the whole flock immediately rushes after him.

Since the caution of a fish is directly related to the experience it has acquired, the older the fish, the more suspicious it is of all kinds of unfamiliar objects. In different species of fish, caution is developed differently. The most cautious species include carp, bream, trout, and ide; the least cautious species include perch, burbot, and pike.

The gregarious lifestyle plays a big role. It is easier for a flock to escape from enemies, find food and places convenient for breeding.

Thus, the “wit,” “intelligence,” and “cunning” of fish are explained by the existence of innate instinct and acquired experience. Instinctively, the fish is afraid of swinging the rod, shaking the soil, splashing in the water, it avoids thick and rough fishing line, a hook that is not disguised by the bait, etc. This means that the fisherman must be able to disguise his tackle, be careful and observant.

Can fish see in water? Agree that the question is rather strange, and the answer to it can only be in the affirmative. Another thing, how? Do they distinguish colors, can they perceive the above-water world, how does their vision depend on the transparency of the water, etc.?

Let's start with the fact that the visual acuity of fish depends entirely on the transparency of the water. Freshwater fish have poor vision. The water in ponds is always cloudy, and allows them to distinguish objects located at a distance of no more than two to three meters. For this reason, freshwater fish hunt and feed mainly at night. In clear water, fish can see much further, up to 10 meters. But the outlines of objects are not clear, which is due to the special structure of the eye.

The eyes of fish resemble a camera, in which the lens acts as a lens, and the retina acts as a matrix on which the image is formed. The lens cannot change its shape, so fish see distant objects blurry. In order to somehow focus the image, it, like a camera lens, can bring the lens closer or move away from the retina, making the image more or less clear. Despite this, it is capable of distinguishing objects well at a distance of no more than one and a half meters. The viewing sector is quite wide and ranges from 150-170 degrees.

A person, as we know, sees very poorly in water, which is due to a completely different refraction of the sun's rays. The same goes for fish. She is able to perceive the surface world only in a distorted form. True, she sees objects at the zenith well. To understand how a fish sees the surface world, it is enough to immerse a mirror in the water at a slight angle and study the reflection that appears in it. However, some species of fish are blind out of water, while the same mudskipper sees perfectly well when on land.

Scientists have studied the vision of some species of fish and came to the conclusion that it depends on their living conditions, hunting methods, and the nature of the environment. Predatory fish have the sharpest vision. These include: pike perch, trout, perch, pike. Fish that lead a bottom lifestyle also have excellent vision. As we understand, visual acuity here is directly tied to the method of obtaining food. In addition, most predators are nocturnal, and it is extremely important for them to distinguish objects in complete darkness. For this purpose, the same bream uses a photosensitive secretion, which is secreted by its retina. The catfish has a slightly different night vision device, which is represented by nerve, light-sensitive fibers.

Marine deep-sea fish use luminous organs. These include, for example, photoblepharon. It illuminates the surrounding space with special “flashlights” located in the eye area. Inside them are bacteria that emit light. If desired, the fish can increase or decrease the intensity of the glow.

Fish eyes can be positioned differently. It all depends on their lifestyle. In bottom-dwelling fish such as flounder, they are located on top. Other representatives have them on both sides of the head. In the fry of the same flounder, the eyes are located in the same way as in ordinary fish. And their body is not flat. The thing is that they live in the water column and feed on plankton. But, along with a change in lifestyle and the transition to a bottom existence, the shape of their body and the location of their eyes change. Despite this, the flounder's vision does not get worse. Her eyes can move independently of each other, which greatly expands their field of view.

The hammerhead fish has eyes located on both sides of its outgrowth, which is due to the peculiarities of its hunting. She hunts stingrays, which have a formidable weapon in the form of spikes on their tail. If the eyes had been positioned differently, the hammerhead fish would certainly have become their victim.

Changes in the color of the body of fish are due to the fact that fish adapt to the conditions in which they live; the color of their body becomes similar to the color of the soil, or acquires a kind of “camouflage” color if they live among aquatic plants. Compared to animals living on land, fish see the surface world somewhat differently. If you look vertically upward, then the fish see everything without distortion, but if at an angle to the side, then due to the refraction of the ray of vision and two media - air and water, the picture is distorted.

Vision in fish. For fish, maximum visibility in clear water does not exceed 10 - 12 meters, this is all because the optical properties of water do not allow them to see far. The visibility distance may be reduced, the reason for this may be: the color of the water, the turbidity of the water, lighting, etc. At a distance of no more than 2 meters, fish see objects most clearly. Predators that prefer daylight and live in clear water see best - trout, grayling, pike, asp. Some fish that feed on plankton and bottom organisms (catfish, bream, eel, burbot, pike perch, etc.) have photosensitive elements in the retina that are capable of perceiving weak light rays. Thanks to these elements, these fish see quite well in the dark.

The angle of view of fish is arranged in this way: They can see objects in an area of ​​about 150° vertically and up to 170° horizontally. From the water in the air, the fish sees objects as if through a round “window”, limited by a visual angle of about 97°. Accordingly, if the fish swims closer to the surface, the “window” will become smaller and smaller.

Can the fish see the fisherman?

Near the shore, the fish is a very good fisherman, but does not see him. This is precisely due to the refraction of the ray of vision described above. Therefore, in the line of sight, camouflage makes sense. Therefore, you should not wear clothes with bright colors when fishing, but rather, as a camouflage, choose a more protective color that will blend into the general background.

In shallow water, the likelihood that the fish will notice the angler is much less than when fishing in deeper places, near the shore. From all this we can conclude: that sitting is always better than standing and there is less chance of being caught by a fish. That is why a spinner who hunts from a boat is recommended to fish (throw bait and fish out a predator) while sitting, not only to comply with safety precautions, but also to try not to be noticed by the fish.

The eye is a perfect optical device. It resembles a photographic camera. The lens of the eye is like a lens, and the retina is like a film on which the image is produced. In terrestrial animals, the lens is lentil-shaped and can change its curvature. This makes it possible to adapt vision to distance.

A person sees very poorly under water. The ability to refract light rays in water and the lens of the eye of terrestrial animals is almost the same, so the rays are concentrated at a focus far behind the retina. On the retina itself, an unclear, blurry image is obtained.

The lens of the fish's eye is spherical; it refracts rays better, but cannot change shape. And yet, to some extent, fish can adapt their vision to distance. They achieve this by bringing the lens closer to or moving away from the retina using special muscles.

In practice, fish in clear water can see no further than 10-12 meters, but clearly - only within one and a half meters.

The angle of view of fish is very wide. Without turning their body, they can see objects with each eye vertically in a zone of about 150° and horizontally up to 170°. This is explained by the location of the eyes on both sides of the head and the position of the lens, shifted towards the cornea itself.

The surface world must seem completely unusual to the fish. Without distortion, the fish sees only objects located directly above its head - at the zenith. For example, a cloud or a soaring seagull. But the sharper the angle of entry of the light beam into the water and the lower the surface object is located, the more distorted it appears to the fish. When the light beam falls at an angle of 5-10°, especially if the water surface is choppy, the fish stops seeing the object altogether.

The rays coming from the eye of the fish outside the cone of 97.6° are completely reflected from the water surface, and it appears mirror-like to the fish. It reflects the bottom, aquatic plants, and swimming fish.

On the other hand, the peculiarities of the refraction of rays allow the fish to see seemingly hidden objects. Let's imagine a body of water with a steep, steep bank. A person sitting on the shore will not see the fish - it is hidden by the coastal ledge, but the fish will see the person.

Objects half-submerged in water look fantastic. This is how, according to L. Ya. Perelman, a person who is chest-deep in water should appear to fish: “For them, walking through shallow water, we split into two, turning into two creatures: the upper one is legless, the lower one is headless with four legs! As we move away from the underwater observer, the upper half of our body becomes increasingly compressed in the lower part; at some distance, almost the entire surface body disappears - only one freely floating head remains.”

Even when going underwater, it is difficult for a person to check how fish see. With the naked eye, he will not see anything clearly at all, but when looking through a glass mask or from the window of a submarine, he will see everything in a distorted form. Indeed, in these cases, there will also be air between the human eye and the water, which will certainly change the course of the light rays.

How fish see objects located outside the water was verified by underwater photography. Using special photographic equipment, photographs were obtained that fully confirmed the considerations expressed above. An idea of ​​how the surface world appears to underwater observers can be formed by lowering a mirror under water. At a certain tilt, we will see the reflection of surface objects in it.

The structural features of the fish eye, as well as other organs, depend primarily on the living conditions and their lifestyle.

More sharp than others are the daytime predatory fish: trout, asp, pike. This is understandable: they detect prey mainly by sight. Fish that feed on plankton and bottom organisms can see well. Their vision is also of paramount importance for finding prey.

Our freshwater fish - bream, pike perch, catfish, burbot - hunt more often at night. They need to see well in the dark. And nature took care of it. Bream and pike perch have a light-sensitive substance in the retina of their eyes, and catfish and burbot even have special bundles of nerves that perceive the weakest light rays.

Anomalops and photoblepharon fish, living in the waters of the Malay Archipelago, use their own lighting in the dark. The flashlights are located near their eyes and shine forward, just like car headlights. The glow is caused by bacteria located in special cones. The lanterns can be switched on and off at the owners' request. Anomalops turns them off, turning the luminous side inward, and photoblepharon closes the lanterns, like a curtain, with a fold of skin.

The location of the eyes on the head also depends on the lifestyle. Many bottom fish - flounder, catfish, stargazer - have eyes located in the upper part of the head. This allows them to better see enemies and prey passing above them. Interestingly, in infancy, flounder eyes are located in the same way as most fish - on both sides of the head. At this time, flounders have a cylindrical body shape, live in the water column and feed on zooplankton. Later they switch to feeding on worms, mollusks, and sometimes fish. And then remarkable transformations occur with flounders: their left side begins to grow faster than their right, the left eye moves to the right side, the body becomes flat, and eventually both eyes end up on the right side. Having completed the transformation, flounders sink to the bottom and lie on their left side - it’s not for nothing that they are aptly nicknamed couch potatoes.

The eyes of flounders have another feature. They can turn in different directions independently of one another. This allows fish to simultaneously monitor the approach of prey or an enemy from the right and left.

V. Sabunaev, "Entertaining ichthyology"