Location of paired and unpaired fins in pike. Unpaired fins of fish. Additional organs in fish

Read: Variety of fish: shape, size, color

Fish fins: shape, structure.

Read more: Fish buoyancy; Swimming fish; flying fish

At various fish sizes, shape, number, position and functions of the fins are different. But their original and main role is that the fins allow you to maintain the balance of the body in the water, participate in maneuvering movement.

All fins in fish are divided into paired, which correspond to the limbs of higher vertebrates, as well as unpaired. Paired fins include pectoral (P - pinna pectoralis) and ventral (V - pinna ventralis). Unpaired fins include dorsal (D - p. dorsalis); anal (A - p. analis) and tail (C - p. caudalis).

A number of fish groups, in particular salmonids, characins, killer whales, and others, have a so-called adipose fin behind the dorsal fin, which is devoid of fin rays (p. adiposa).

Pectoral fins are common in bony fish, while in moray eels and some others, they are absent. Lampreys and hagfish are completely devoid of both pectoral and ventral fins. In stingrays, on the contrary, the pectoral fins are greatly enlarged and play the main role as organs of their movement. But the pectoral fins have developed especially strongly in flying fish, which allows them to jump out of the water at high speed, literally soar in the air, while flying long distances above the water. The three rays of the pectoral fin of the gurnard are completely isolated and act as legs when crawling on the ground.

The pelvic fins of various fish can take different position, which is associated with a shift in the center of gravity caused by the contraction of the abdominal cavity and the concentration of the viscera in the front of the body. Abdominal position - when the pelvic fins are located approximately in the middle of the abdomen, which we observe in sharks, herrings, cyprinids. In the thoracic position, the ventral fins are shifted to the front of the body, as in perciformes. And finally, the jugular position, in which the ventral fins are located in front of the pectoral and on the throat, like in codfish.

In some species of fish, the ventral fins are turned into spines - like a stickleback, or into a sucker, like a lumpfish. In male sharks and rays, the posterior rays of the ventral fins have evolved into copulatory organs and are called pterygopodia. The pelvic fins are completely absent in eels, catfish, etc.

At different groups fish can have a different number of dorsal fins. So, in herring-like and cyprinids, it is one, mullet-like and perch-like have two dorsal fins, and in cod-like ones there are three. In this case, the location of the dorsal fins can be different. In pike, the dorsal fin is shifted far back, in herring-like, cyprinids it is located in the middle of the body, and in fish such as perch and cod, which have a massive front part of the body, one of them is located closer to the head. The longest and highest dorsal fin of a sailboat fish, reaching really large sizes. In flounder, it has the form of a long ribbon running along the entire back and, simultaneously with almost the same anal, is their main organ of movement. And such mackerels as mackerel, tuna and saury acquired in the process of evolution small additional fins located behind the dorsal and anal fins.

Separate rays of the dorsal fin sometimes stretch into long threads, and in the monkfish the first ray of the dorsal fin is shifted to the muzzle and transformed into a kind of fishing rod. It is he who acts as a bait, like a deep-sea anglerfish. The latter has a special bait on this rod, which is their luminous organ. The first dorsal fin of the sticky fish also shifted to the head and turned into a real sucker. The dorsal fin in sedentary demersal fish species is poorly developed, such as in catfish, or may be completely absent, as in stingrays. The famous electric eel also lacks a dorsal fin....

A number of fish (salmon, characin, orcas, etc.) have an adipose fin behind the dorsal fin, it is devoid of fin rays (p.adiposa).

Pectoral fins are common in bony fish, while moray eels and some others lack them. Lampreys and hagfish are completely devoid of pectoral and ventral fins. In stingrays, the pectoral fins are greatly enlarged and play the main role as organs of their movement. Especially strong pectoral fins have developed in flying fish. The three rays of the pectoral fin in the gurnard act as legs when crawling on the ground.

The pelvic fins can take a different position. Abdominal position - they are located approximately in the middle of the abdomen (sharks, herring-like, cyprinids). In the thoracic position, they are shifted to the front of the body (perch-like). Jugular position, fins located in front of the pectorals and on the throat (cod).

In some fish, the ventral fins are turned into spines (stickleback) or into a sucker (pinogora). In male sharks and rays, the posterior rays of the ventral fins have evolved into copulatory organs. They are completely absent in eels, catfish, etc.

There may be a different number of dorsal fins. In herring and cypriniforms, it is one, mullet and perch - two, in cod - three. Their location may be different. In pike, it is shifted far back, in herring-like, cyprinids - in the middle of the body, in perch and cod - closer to the head. The longest and highest dorsal fin in sailboat fish. In flounder, it looks like a long ribbon running along the entire back and at the same time with almost the same anal fin, it is their main organ of movement. Mackerel, tuna and saury have small additional fins behind the dorsal and anal fins.

Separate rays of the dorsal fin sometimes stretch into long threads, and in the anglerfish the first ray of the dorsal fin is shifted to the muzzle and transformed into a kind of fishing rod, like in the deep-sea anglerfish. The first dorsal fin of the sticky fish also shifted to the head and turned into a real sucker. The dorsal fin in sedentary demersal fish species is poorly developed (catfish) or absent (stingrays, electric eel).

Tail fin:
1) isobathic - the upper and lower lobes are the same (tuna, mackerel);
2) hypobatic - the lower lobe is elongated (flying fish);
3) epibate - the upper lobe is elongated (sharks, sturgeons).

Types of caudal fins: forked (herring), notched (salmon), truncated (cod), rounded (burbot, gobies), semilunar (tuna, mackerel), pointed (eelpout).

The function of movement and balance has been assigned to the fins from the very beginning, but sometimes they perform other functions. The main fins are dorsal, caudal, anal, two ventral and two pectoral. They are divided into unpaired - dorsal, anal and caudal, and paired - thoracic and abdominal. Some species also have an adipose fin located between the dorsal and caudal fins. All fins are driven by muscles. In many species, the fins are often modified. So, in males of viviparous fish, the modified anal fin has turned into a mating organ; in some species, the pectoral fins are well developed, which allows the fish to jump out of the water. Gourami have special tentacles, which are thread-like pelvic fins. And in some species that burrow into the ground, fins are often absent. The tail fins of guppies are also an interesting creation of nature (there are about 15 species and their number is growing all the time). The movement of the fish is started by the tail and caudal fin, which with a strong blow send the body of the fish forward. The dorsal and anal fins provide balance to the body. The pectoral fins move the body of the fish during slow swimming, serve as a rudder and, together with the ventral and caudal fins, ensure the equilibrium position of the body when it is real. In addition, some species of fish can rely on pectoral fins or move with their help on a hard surface. The pelvic fins perform mainly the function of balance, but in some species they are changed into a suction disk, which allows the fish to stick to a hard surface.

1. Dorsal fin.

2. Adipose fin.

3. Caudal fin.

4. Pectoral fin.

5. Pelvic fin.

6. Anal fin.

The structure of the fish. Types of tail fins:

Truncated

Split

lyre-shaped

24. The structure of the skin of fish. The structure of the main types of fish scales, its functions.

The skin of fish performs a number of important functions. Located on the border of the outer and internal environment organism, it protects the fish from external influences. At the same time, separating the body of the fish from the surrounding liquid medium with dissolved in it chemicals, fish skin is an effective homeostatic mechanism.

Fish skin regenerates quickly. On the one hand, partial excretion occurs through the skin final products metabolism, and on the other hand, the absorption of certain substances from external environment(oxygen, carbonic acid, water, sulfur, phosphorus, calcium and other elements that play an important role in life). The skin as a receptor surface plays an important role: thermo-, baro-chemo- and other receptors are located in it. In the thickness of the corium, the integumentary bones of the skull and pectoral fin belts are formed.

In fish, the skin also performs a rather specific - supporting - function. On the inside the skin is fixed muscle fibers of skeletal muscles. Thus, it acts as a supporting element in the composition of the musculoskeletal system.

The skin of fish consists of two layers: the outer layer of epithelial cells, or epidermis, and the inner layer of connective tissue cells - the skin proper, dermis, corium, cutis. Between them, a basement membrane is isolated. The skin is underlain by a loose connective tissue layer (subcutaneous connective tissue, subcutaneous tissue). In many fish, fat is deposited in the subcutaneous tissue.

The epidermis of fish skin is represented by a stratified epithelium consisting of 2–15 rows of cells. The cells of the upper layer of the epidermis are flat. The lower (growth) layer is represented by one row of cylindrical cells, which, in turn, originate from the prismatic cells of the basement membrane. The middle layer of the epidermis consists of several rows of cells, the shape of which varies from cylindrical to flat.

The outermost layer of epithelial cells becomes keratinized, but unlike terrestrial vertebrates in fish, it does not die off, retaining its connection with living cells. During the life of the fish, the intensity of keratinization of the epidermis does not remain unchanged, it reaches its greatest extent in some fish before spawning: for example, in male cyprinids and whitefishes, in some places of the body (especially on the head, gill covers, sides, etc.) the so-called pearl rash - a mass of small white bumps that roughen the skin. After spawning, she disappears.

The dermis (cutis) consists of three layers: a thin upper (connective tissue), a thick middle mesh layer of collagen and elastin fibers and a thin basal layer of high prismatic cells, giving rise to the two upper layers.

In active pelagic fish, the dermis is well developed. Its thickness in areas of the body that provide intensive movement (for example, on the caudal peduncle of a shark) is greatly increased. The middle layer of the dermis in active swimmers can be represented by several rows of strong collagen fibers, which are also interconnected by transverse fibers.

In slow-swimming littoral and bottom fish, the dermis is loose or generally underdeveloped. In fast-swimming fish, in areas of the body that provide swimming (for example, the caudal peduncle), subcutaneous tissue is absent. In these places, muscle fibers are attached to the dermis. In other fish (most often slow ones), subcutaneous tissue is well developed.

The structure of fish scales:

Placoid (it is very ancient);

ganoid;

Cycloid;

Ctenoid (the youngest).

placoid fish scale

placoid fish scale(photo above) is characteristic of modern and fossil cartilaginous fish - and these are sharks and rays. Each such scale has a plate and a spike sitting on it, the tip of which goes out through the epidermis. In this scale, the basis is dentin. The spike itself is covered with even harder enamel. The placoid scale inside has a cavity that is filled with pulp - pulp, it has blood vessels and nerve endings.

Ganoid fish scale

Ganoid fish scale has the form of a rhombic plate and the scales are connected to each other, forming a dense shell on the fish. Each such scale is made of a very hard substance - the upper part is made of ganoin, and the lower part is made of bone. This type of scales have a large number of fossil fish, as well as the upper parts in the caudal fin in modern sturgeons.

Cycloid fish scale

Cycloid fish scale found in bony fish and does not have a layer of ganoin.

Cycloid scales have a rounded neck with a smooth surface.

Ctenoid fish scale

Ctenoid fish scale also found in bony fish and does not have a layer of ganoin, it has spikes on the back. Usually the scales of these fish are tiled, and each scale is covered in front and on both sides by the same scales. It turns out that the back end of the scale comes out, but it is also lined with another scale from below, and this type of cover retains the flexibility and mobility of the fish. Annual rings on the scales of fish allow you to determine its age.

The arrangement of scales on the body of the fish goes in rows and the number of rows and the number of scales in the longitudinal row do not change with the age of the fish, which is an important systematic feature for different types. Let's take this example - the lateral line of goldfish has 32-36 scales, while the pike has 111-148.

THEME 1.

Fish fins. Organi dihannya, zoru that hearing.

FISH FIN

The fins are characteristic feature fish structures. They are divided into paired, corresponding to the limbs of higher vertebrates, and unpaired, or vertical.

Paired fins include pectoral and ventral fins. Unpaired ones consist of dorsal (from one to three), caudal and anal (one or two). Salmon, grayling and other fish have an adipose fin on their back, while mackerel, tuna, saury have small additional fins behind the dorsal and anal fins. The position of the fins on the body, their shape, size, structure and functions are very diverse. Fish use their fins to move, maneuver and maintain their balance. In moving forward, the main role in most fish is played by the caudal fin. It does the work of the most advanced propeller with rotary blades and stabilizes the movement. The dorsal and anal fins are a kind of keels to give the body of the fish the desired stable position.

Two sets of paired fins are used for balance, braking and control.

The pectoral fins are usually located behind the gill openings. The shape of the pectoral fins is related to the shape of the caudal: they are rounded in fish that have a rounded tail. Good swimmers have pointed pectoral fins. The pectoral fins of flying fish are especially strongly developed. Due to the high speed of movement and the blows of the tail fin, flying fish jump out of the water and soar on pterygoid pectoral fins, covering a distance of up to 100-150 m in the air. Such flights help them hide from the pursuit of predators.

The pectoral fins of the monkfish have a jointed, fleshy base. Relying on them angler moves along the bottom in leaps, as if on legs.

The location of the pelvic fins different fish unequally. In low organized (sharks, herring, cyprinids) they are on the belly. In more highly organized, the pelvic fins move forward, taking a position under the pectorals (perch, mackerel, mullet). In codfish, the pelvic fins are in front of the pectoral fins.

In gobies, the pelvic fins are fused into a funnel-shaped sucker.

The ventral fins of the lumpfish have changed into an even more amazing adaptation. Their suction cup holds the fish so firmly that it is difficult to remove it from the stone.

From unpaired fins Special attention deserves a tail, the complete absence of which is very rare (stingrays). According to the shape and location relative to the end of the spine, several types of caudal fins are distinguished: asymmetric (heterocercal) - in sharks, sturgeons, etc .; falsely symmetrical (homocercal) - in most bony fish.

The shape of the caudal fin is closely related to the way of life of the fish6 and especially to the ability to swim. Good swimmers are fish with crescent, forked and notched tails. Less mobile fish have a truncated rounded tail fin. For sailboats, it is very large (up to 1.5 m long), they use it as a sail, exposing it above the surface of the water. In spiny fish, the rays of the dorsal fin are strong spines, often equipped with poisonous glands.

A peculiar transformation is observed in the sticky fish. Her dorsal fin moves to her head and turns into a suction disk, with which she attaches herself to sharks, whales, and ships. In anglers, the dorsal fin shifts to the muzzle and extends into a long thread that serves as a bait for prey.

cartilaginous fish .

Paired fins: The shoulder girdle looks like a cartilaginous semicircle lying in the muscles of the body walls behind the branchial region. On its lateral surface on each side there are articular outgrowths. The part of the girdle lying dorsal to this outgrowth is called scapular department, ventral - coracoid department. At the base of the skeleton of the free limb (pectoral fin) there are three flattened basal cartilages attached to the articular outgrowth of the shoulder girdle. Distal to the basal cartilages are three rows of rod-shaped radial cartilages. The rest of the free fin is his skin lobe– supported by numerous thin elastin threads.

Pelvic girdle represented by a transversely elongated cartilaginous plate lying in the thickness of the abdominal muscles in front of the cloacal fissure. The skeleton of the pelvic fins is attached to its ends. IN pelvic fins there is only one base element. It is greatly elongated and one row of radial cartilages is attached to it. The rest of the free fin is supported by elastic threads. In males, the elongated basal element extends beyond the fin lobe as the skeletal base of the copulatory outgrowth.

unpaired fins: As a rule, they are represented by a caudal, anal, and two dorsal fins. The tail fin of sharks is heterocercal, i.e. its upper lobe is much longer than the lower one. It enters the axial skeleton - the spine. The skeletal base of the caudal fin is formed by elongated upper and lower vertebral arches and a row of radial cartilages attached to the upper arches of the caudal vertebrae. Most of the tail blade is supported by elastic threads. At the base of the skeleton of the dorsal and anal fins lie radial cartilages, which are immersed in the thickness of the muscles. The free blade of the fin is supported by elastic threads.

Bony fish.

Paired fins. Represented by pectoral and ventral fins. The shoulder girdle serves as a support for the chest. The pectoral fin at its base has one row of small bones - radial extending from the scapula (component of the shoulder girdle). The skeleton of the entire free blade of the fin consists of segmented skin rays. The difference from cartilage is the reduction of basals. The mobility of the fins is increased, since the muscles are attached to the expanded bases of the skin rays, which flexibly articulate with the radials. The pelvic girdle is represented by closely interlocking paired flat triangular bones that lie in the thickness of the musculature and are not connected with the axial skeleton. Most of the pelvic fins, which are bony in the skeleton, lack basals and have reduced radials; the lobe is supported only by skin rays, the expanded bases of which are directly attached to the pelvic girdle.

Unpaired limbs. Represented by dorsal, anal (undercaudal) and caudal fins. Anal and dorsal fins consist of bone rays, subdivided into internal (hidden in the thickness of the muscles) pterygiophores(corresponding to the radials) and outer fin rays - lepidotrichia. tail fin asymmetrical. In it, the continuation of the spine - urostyle, and behind and below it with a fan are flat triangular bones - hypuralia, derivatives of the lower arches of underdeveloped vertebrae. This type of fin structure is externally symmetrical, but not internally - homocercal. The outer skeleton of the caudal fin is composed of numerous skin rays - lepidotrichia.

There is a difference in the location of the fins in space - in cartilaginous horizontally to maintain in water, and in teleosts vertically because they have a swim bladder. Fins during movement perform various functions:

unpaired - dorsal, caudal and anal fins, located in the same plane, help the movement of the fish;
paired - pectoral and ventral fins - maintain balance, and also serve as a rudder and brake.

Pisces use many different ways to communicate. Of course, not so much as people or other higher vertebrates. To communicate some information to surrounding fish or other animals, fish can use chemical, electrolocation, sound and, as it turned out, visual methods, that is, they use “sign language” to communicate. And although anglers, unlike aquarists, divers or spearfishers, are less likely to be able to look live fish in the eye, some basic fish language can be learned.

Familiarization
The visible signals that fish can give to surrounding fish or other animals can be divided into several main groups. The first group is spawning postures or even gestures and facial expressions. After all, the movements of the fins can be called gestures, ajar and even twisted mouths - facial expressions.

The second group of visual signals demonstrates aggression, attack, and they indicate that this individual has entered the "warpath". There is also large group defensive gestures. This is not open aggression, but such gestures clearly show that we are peaceful fish, but "our armored train is on a siding." Fish show these gestures more often than others.

The same group of gestures applies to the protection of the territory, and to the protection of one's found (caught) food object, and to the protection of cubs.

Another important visual stimulus is the coloration of the fish. In a sufficient number of fish species, under stress, during spawning, during an aggressive attack or defense of their "good", a color change occurs that signals something out of the ordinary. Something similar happens to a person when, from anger, shame or tension, he blushes and gives himself away.

Unfortunately, while the sign language of fish is far from being studied completely and by no means for all species, but still knowledge general principles gesture communication of fish will help to understand the fish. By the way, scientists suggest that fish of each species have a personal sign language, which is very well understood by closely related species and much worse by species far removed in their position in the taxonomy.

Gestures of aggression and defense
In fish of different species, these gestures can, of course, vary, but they have much in common and are understandable to other fish. The Greatest Animal Behavior Researcher, Laureate Nobel Prize Konrad Lorenz said: "Aggression is one of the most important factors in maintaining the community structure of most animal groups."

Lorentz pointed out that the existence of groups with close individual ties between individuals is possible only in animals with enough developed ability to directed aggression, in which the association of two or more individuals contributes to better survival.

In fish, the key aggressive gesture can be considered as follows: one of the fish turns to the other and begins to open its mouth wide (this is how dogs, wolves and other land animals snarl). This gesture can be deciphered as a gesture of a frontal threat (attack).

So if a shark is snarling at you, leave the hell out of it. While the mouth is still open, this is some kind of beginning of a threat, territorial defense or any defensive gesture.

An important key point not only of this aggressive gesture, but also of other gestures of the same group: a fish with an open mouth seems larger, and therefore more terrible and impressive. At the same time, her attack looks more convincing and effective.

By the way, breeding the pectoral fins to the sides, protruding gill covers, inflating the body with various tetraodon also leads to a general increase in the volume of the body of a frightening fish.

Some poses of aggression and active defense are used by male fish to conquer females before spawning. We are not talking about the direct use of gestures at this moment, but the female sees what a big and serious suitor is in front of her.

For fish, these “exaggeration” postures are very important. After all, they grow all their lives, and for them size plays a paramount role. Adult individuals, already showing aggressive behavior with might and main, are often large in size.

And the one who is bigger is stronger, and older, and more experienced, and more important. That is, he has the right to food, territory, and the best female. Therefore, fish often try to visually exaggerate their size.

An exaggeration of size that frightens the enemy is also achieved by occupying a higher point in space. Enough to force the opponent to look up, and he will feel inferior to you. Demonstration of the sides of the body and fluttering of the caudal fin and the whole body is more often a manifestation of spawning behavior, that is, spawning gestures, or releasers.

However, in some fish (for example, ruffs and other perches), such a demonstration of the sides and trembling of the tail is a typical aggressive gesture. A similar gesture of some fish is called "lateral threat". Unlike the "frontal threat", it does not look so intimidating.

The spreading of the fins, often accompanied by trembling (or fluttering, or even shaking of the body), can be interpreted, depending on the situation, both as aggression, and as active defense, and as gestures of spawning behavior.

And in many territorial fish, such lateral displays, which are accompanied by vibrations of the body and spreading of the fins, have a dual function. For fish of its own species, but of the opposite sex, this is an attractive maneuver, showing what a beautiful, big and wonderful partner swims at your side.

And for relatives of the same sex, these gestures mean one thing: this is my female and my place, and you can leave! If one male (or female) spreads his fins, and his opponent, on the contrary, folded them, this means the complete surrender of the latter.

When the enemy, in response, inflates his fins and vibrates his body, this means that he accepts the fight and now there will be a performance. A very important evolutionary point is the demonstration of aggression instead of a direct attack. Indeed, in its original form, aggression involves an attack on an object, inflicting physical damage to it, or even murder.

In the process of animal evolution, an aggressive attack was replaced by a demonstration of the threat of the possibility of an attack, especially during skirmishes between individuals of the same species. Demonstration, causing fear in the enemy, allows you to win a skirmish without resorting to a fight that is very dangerous for both sides.

Physical confrontation is replaced by psychological confrontation. Therefore, developed aggressive behavior, including many threats and frightening actions, is useful for the species, and for well-armed species it is simply saving.

This is why Lorentz argued that well-designed aggressive behavior is one of the remarkable achievements of natural selection and is essentially humane.

In fish, one of the main instruments of demonstration (instead of attack) is spikes in the fins, prickly gill covers or plaques on the body. That is, it is easiest to scare the enemy by showing him the means of defense and attack that he has this species animals.

Therefore, fish, threatening, spread their fins and raise their spikes; many stand vertically in the water, exposing them to meet the enemy.

The fight process in fish consists of five or six successive phases:

warning with the adoption of an appropriate posture;
excitation of opponents, usually accompanied by a change in color;
approaching fish and demonstrating a threat pose;
mutual blows with the tail and mouth;
retreat and defeat of one of the opponents.

There are also phases of breaks to relieve tension and to rest during the fight or demonstration of strength.

Body coloration and pattern as spawning releasers
There are a lot of such visual and identification signals. During spawning, when the fish has a special hormonal background, in many species the color and pattern change - this is a signal that it is ready for reproduction.

For reliability, chemical and other signals are also actively working, so that the fish is not mistaken and the species continues to exist. In addition to spawning, color and pattern help fish during schooling: often the stripes on the body serve as a visual stimulus, helping thousands of fish to stay close and correctly positioned relative to each other.

Coloring makes it possible to recognize your relative or, conversely, an enemy and dangerous individual. Many fish, especially those in which visual signals play an important role (pike, perch, zander and others), remember well external features"own" and "foreign" fish. Often two or three “lessons” are enough for the fish to remember the color and pattern of the hostile fish well.

Sometimes not only the color of the whole body, but also the color of individual fins (for example, ventral or pectoral), or individual brightly colored areas on the body (abdomen, back, head) signal to potential partners that “it is ready for spawning!”.

A spot on the abdomen of many females indicates that there are a lot of eggs in the abdomen, it is enlarged and bright. However, in most cases, bright coloration is destructive outside of spawning: it unmasks peaceful fish in front of predators, and, on the contrary, reveals a predator ahead of time.

So most of the fish in our reservoirs in the usual non-spawning period have a gray, inconspicuous appearance, and the more important for them is developed gesticulation.
In addition to spawning behavior or identification, “own” or “alien” coloration can work as a factor determining status.

The brighter the color and the clearer the pattern, the higher the social status of this individual. This is not always the case, but often. Fish can use their coloration to show threat (strong, intense coloration) or submissiveness (less bright or dull coloration), usually supported by appropriate, information-enhancing gestures. Bright coloring is actively used by fish that protect their offspring, grow juveniles and drive away other fish that are dangerous for young animals. She also helps the juveniles to identify their parents, to notice them among other fish.

In parental behavior, fish have a highly developed not only body color language, but also sign language. The juvenile quickly remembers that the flapping of the ventral fins and the pressed pectoral fins mean the call to "swim to the mother"; the bend of the body and the parted mouth - "swim after me"; splayed fins are a command to hide for cover.

For normal relationships between parents and juveniles, it is necessary to suppress some reactions. Very interesting examples of this have been observed in fish. Some chromis (family Cichlids) carry fry in their mouths; at this time, adult fish do not feed at all.

A funny case is described with a male of one species of chromis, whose representatives every evening carry juveniles to the "bedroom" - a hole dug in the sand. This “father” collected fry in his mouth, grabbing one at a time that had strayed to the side, and suddenly saw a worm: after a little hesitation, he finally spat out the fry, grabbed and swallowed the worm, and then began to collect the “cubs” again to transfer them to the hole .

A straightened, standing dorsal fin indicates both the beginning aggressive behavior(for example, when protecting their territory), and about an invitation to spawn.

Rituals and demonstrations
To understand the sign language of fish, you need to know their rituals and the meaning of various postures and gestures, which say a lot about fish intentions. Rituals and demonstrative acts of behavior shown by animals in conflict situations, can be divided into two groups: rituals of threat and rituals of appeasement, inhibiting aggression from stronger relatives. Lorentz identified several main features of such rituals.

Demonstrative substitution of the most vulnerable part of the body. Interestingly, this behavior is often shown by dominant animals. So, when two wolves or dogs meet, the stronger animal turns its head away and exposes its rival to the area of the carotid artery, curved towards the bite.

The meaning of such a demonstration is that the dominant signals in this way: "I'm not afraid of you!". This is more likely to apply to more highly developed animals, but some fish also show similar behavior. For example, cichlids display folded fins and a caudal stalk to a strong opponent.

Fish have organs that can be called organs of ritual behavior. These are fins and gill covers. Ritual are modified fins, which in the process of evolution turn into spikes or spines, or, conversely, into veil formations. All these "decorations" are clearly displayed in front of other individuals of their species, in front of a female or rival. There is also ritual coloring.

For example, tropical fish have a false "eye" - a bright spot in the upper corner of the dorsal fin, imitating the eye of a fish. The fish exposes this corner of the fin to the enemy, the enemy clings to it, thinking that it is an eye and it will now kill the victim.

And he just rips out a few rays of the dorsal fin with this bright spot, and the victim safely swims away almost whole and unharmed. Obviously, in the course of evolution, both the decorations themselves and the ways of displaying them developed in parallel.

The demonstration of signaling structures carries vital information that indicates to other individuals the sex of the demonstrating animal, its age, strength, ownership of a given area, etc.

Ritual demonstrations in territorial behavior are very important and interesting in fish. By themselves forms of aggressive territorial behavior are far from being exhausted by a direct attack, a fight, chases, etc. It can even be said that such "hard" forms of aggression, associated with inflicting wounds and other damage on the enemy, are not a very frequent occurrence in the general system of individualization of a territory.

Direct aggression is almost always accompanied by special "ritual" forms of behavior, and sometimes the protection of the site is completely limited to them. And the clashes themselves on territorial grounds are relatively rarely accompanied by serious damage to the enemy. Thus, frequent fights of goby fish at the boundaries of plots are usually very short-lived and end with the flight of the "intruder", after which the "owner" begins to swim vigorously in the conquered area.

Fish actively mark their territory. Each species does this in its own way, depending on which sensory systems prevail in that species. So, species that live in small well-visible areas visually mark the territory. For example, the same coral fish. A clear, bright, unusual and distinct body pattern (and color) from other fish - all this in itself indicates that the mistress of the population of this species is located in this area.

Hierarchy and poses of fish with gestures
The first meeting of animals rarely goes without some tension, without a mutual manifestation of aggressiveness. There is a fight, or individuals demonstrate their hostility with decisive gestures, threatening sounds. However, after the relationship is clarified, fights rarely occur. Meeting again, the animals unquestioningly give way, food or other object of competition to a stronger rival.

The order of subordination of animals in a group is called a hierarchy. Such an orderliness of relationships leads to a decrease in energy and mental costs arising from constant competition and showdown. Animals that are at the lower levels of the hierarchy, subjected to aggression from other members of the group, feel oppressed, which also causes important physiological changes in their body, in particular, the occurrence of an increased stress response. It is these individuals that most often become victims of natural selection.

Each individual is either superior in strength to the partner, or inferior to him. Such a hierarchical system is formed when fish clash in the struggle for a place in a reservoir, for food and for a female.

The fish only opened its mouth and raised its fin, while its size visually increased by almost 25%. This is one of the most accessible and common ways to raise your authority in the animal kingdom.

In the early stages of the establishment of a hierarchy between fish (for which hierarchy is inherent in principle), there is a lot of fights. After the final establishment of the hierarchy, aggressive collisions between fish individuals practically cease, and the order of subordination of individuals is maintained in the population.

Usually, when a high-ranking fish approaches, subordinate individuals yield to it without resistance. In fish, most often it is size that acts as the main criterion for dominance in the hierarchical ladder.
The number of collisions in a group of animals increases sharply when there is a lack of food, space, or other conditions of existence. The lack of food, causing more frequent collisions of fish in a flock, makes them somewhat spread out to the sides and develop additional feeding area.

Fatal outcomes of fights of very aggressive species of fish in fish farms and aquariums are observed much more often than in natural conditions. This is easily explained by both stress and the inability to disperse rivals. A kind of eternal ring. Therefore, aquarists know how important it is to make plenty of hiding places in the pond if the fish are territorial. It's even safer to keep them separate.

The lowest links in the fish in the hierarchical ladder should demonstrate postures of submission, humility and appeasement. What does the losing fish do? First of all, she raises the “white flag”, that is, she folds her fins, removes spikes, spines and teeth (sharks). These attributes of aggressiveness are removed until better times, that is, before meeting with an even weaker opponent.

The sizes of individuals decrease before our eyes. As far as possible, of course. That is, the losing fish-outsider demonstrates to the enemy: “I am small and unarmed, I am not afraid of you!”. And a strong victorious opponent also understands that he no longer needs to demonstrate his strength, and closes his mouth, assumes a horizontal position, folds his fins, removes thorns and spines (if they are, of course).

Sometimes a defeated fish turns belly up and this also demonstrates its defenselessness. I deliberately do not provide data on specific species here, since there are very few of them, and many have not yet been statistically confirmed.

I hope that interesting information will help anglers to better understand the fish, once again not to frighten and harm both a particular fish and a flock or population as a whole.

Source: Ekaterina Nikolaeva, Fish with us 3/2013 159

Guster

Gustera fish. Gustera differs from the above-described species of bream solely in the number and arrangement of pharyngeal teeth, which are located on each side not five, but seven, and, moreover, in two rows. In body shape, it is very similar to a young bream, or rather, a scavenger, but it has a smaller number of rays in the dorsal (3 simple and 8 branched) and anal (3 simple and 20-24 branched) fins; in addition, her scales are noticeably larger, and the paired fins are reddish in color.

The body of the bream is strongly flattened, and its height is at least a third of its entire length; her nose is blunt, her eyes are large, silvery; the back is bluish-gray, the sides of the body are bluish-silver; unpaired fins are gray, and paired fins are red or reddish at the base, dark gray towards the top. However, this fish, depending on age, season and local conditions, represents significant modifications.

Guster never reaches a significant size. For the most part it is no more than one pound and less than a foot in length; rarely come across one and a half and two pounds, and only in a few areas, for example, in Gulf of Finland. Lake Ladoga, it weighs up to three pounds. This fish has a much wider distribution than raw, blue and glacier.

Gustera is found in almost all European countries: France, England, Sweden, Norway, throughout Germany, Switzerland, and it seems to be absent only in Southern Europe. In all the above-mentioned localities, it belongs to very common fish. In Russia, the bream is found in all rivers, sometimes even rivers, also in lakes, especially in the northwestern provinces, and flowing ponds; in Finland it reaches 62°N. sh.; is also found in the northern parts of Lake Onega, and in northern Russia goes even further - to Arkhangelsk.

It seems to be no longer in Pechora, and in Siberia it was found only recently (Varpakhovsky) in the river. Iset, a tributary of the Tobol. There is no silver bream in the Turkestan region, but in Transcaucasia it has been found to this day in the mouths of the Kura and in the lake. Paleostome, off the coast of the Black Sea. Gustera is a sluggish, lazy fish and, like a bream, loves calm, deep, rather warm water, with a silty or clay bottom, which is why it is very common with this latter.

She lives in one place for a long time and most willingly stays near the very shores (hence her French name - la Bordeliere and Russian shore), especially in the wind, since the shafts, washing away the shores, and in shallow places the very bottom, find various worms and larvae. In not in large numbers it apparently lives in the mouths of rivers and on the seashore itself, as, for example, in the mouths of the Volga and in the Gulf of Finland between Petersburg and Kronstadt.

In spring and autumn, the silver bream is found in extremely dense flocks, from which, of course, its common name came from. However, she rarely travels very far and almost never reaches, for example, the middle reaches of the Volga, where she already lives her own, local, bream. In general, the main mass of these fish accumulates in the lower reaches of the rivers, in the sea, and, like very many others, it makes regular periodic movements: in the spring they go up for spawning, in the fall for wintering.

Entering the autumn for wintering, they lay down on the pits under the rifts in such large masses that in the lower reaches of the Volga it happens to pull out up to 30 thousand pieces in one ton. The food of the silver bream is almost the same as other types of bream: it feeds exclusively on mud and small mollusks, crustaceans and worms contained in it, most often on bloodworms, but also exterminates the eggs of other fish, especially (according to Bloch's observations) rudd caviar.

The spawning of the silver bream starts very late, b. h. at the end of bream spawning - at the end of May or at the beginning of June, in the south a little earlier. At this time, her scales change in color, and paired fins get a brighter red color; in males, in addition, small grain-like tubercles develop on the gill covers and along the edges of the scales, which then disappear again. Usually small bream spawns earlier, large later.

In the Gulf of Finland, other fishermen distinguish two breeds of bream: one breed, according to them, is smaller, lighter, spawns earlier and is called Trinity (by spawning time), and the other breed is much larger (up to 3 pounds), darker in color, spawns later and is called Ivanovo. According to Bloch's observations, in Germany, the largest bream thrashes first, after a week or nine days - a small one.

The silver bream chooses grassy and shallow bays as a spawning place and spawns extremely noisily, like a bream, but incomparably quieter than it: at this time it sometimes even happens to catch it with your hands; in the muzzle, wings and nonsense then catch her by the pound. It usually spawns from sunset to ten in the morning, and each age finishes the game at 3-4 in the morning, but if cold weather interferes, then on the same day.

In the female medium size Bloch counted over 100,000 eggs. According to Sieboldt, the silver bream becomes fertile very early, before it reaches 5 inches in length, so it must be assumed that it spawns in the second year. The main fishing for silver bream is done in the spring - with nets, but in the lower reaches of the rivers, especially on the Volga, even more fishing for this fish occurs in the fall. The most full information about crucian fish is - here.

Gustera generally belongs to low-value fish and is rarely prepared for the future, except when caught in very large numbers. Salted and dried bream on the lower Volga goes on sale under the name ram; in the rest of the Volga region it b. h. is sold fresh and has only local sales. However, it is very suitable for fish soup and in rather greater honor in the Volga provinces, where a saying has developed about it: "Large bream is tastier than small bream."

Where there are a lot of silver bream, there she is very good at bait, especially after spawning. In some places they usually fish for a worm, from the bottom, like a bream, and its biting is similar to the biting of the latter; even more often than a bream, the white bream drags the float to the side without immersing it, and often cuts itself. This is perhaps the most daring and annoying fish, which is a pure punishment for anglers who fish with bait.

It is noticed that she takes it best at night. According to Pospelov, the bream on the river. Teze (in Vladimir province) is allegedly caught on pieces of salted herring. In Germany, in autumn, it also goes well for bread with honey, and on the Volga it is very often caught in winter from holes (for worms). The winter biting of the silver bream has the usual character - it first pulls, then slightly drowns. For catching catfish, pikes and large perches, the bream is one of the best baits, as it is much more tenacious than other types of bream.

In many areas of Russia, for example. in the Dnieper, Dniester, on the middle and lower Volga, occasionally - usually alone and in schools of other fish, b. h. silver bream and roach (vobla) - one fish comes across, occupying, as it were, the middle between bream, silver bream and roach (Abramidopsis), on the river. Mologa, this fish is called ryapusa, in Nizhny Novgorod, Kazan and on the Dnieper - all fish, all fish, on the grounds that it resembles various carp fish: blue bream, bream, roach, rudd.

According to fishermen, as well as some scientists, this is a bastard from bream and roach or silver bream and roach. In Kazan, one fisherman even claimed prof. Kessler that all fish hatch from roach eggs fertilized by male bream. In terms of body shape and pharyngeal teeth, this hybrid is still closer to the genus Abramis.

The height of her body is about 2/7 of the entire length, the mouth occupies the top of the snout and the lower jaw is somewhat curled up; the scales are larger than those of other breams, and there are only 15-18 unbranched rays in the anal fin; the lower lobe of the caudal fin is only slightly longer than the upper lobe than Abramidopsis is already approaching the roach. It is more correct to assume that this is mostly a mixture of bream and roach.

A similar mixture is Bliccopsis abramo-rutilus Holandre, which is probably descended from silver bream and roach, and has occasionally been found here and there alone, both in central Europe and in Russia. According to Kessler, Bliccopsis is also found in Lake. Paleostomy (at the mouth of the Rion in the Caucasus). The body of the bream is high, strongly compressed from the sides, covered with thick, tightly fitting scales. Her head is relatively small. The mouth is small, oblique, semi-inferior, retractable.

The eyes are big. The dorsal fin is high, the anal fin is long. The back is bluish-gray, the sides and belly are silvery. The dorsal, caudal and anal fins are gray, the pectoral and ventral fins are yellowish, sometimes reddish, which is how it differs externally from the bream. In addition, the silver bream, unlike the bream, has larger scales, especially at the dorsal fin, as well as on the back; behind the back of the head it has a groove not covered with scales.

Gustera lives in rivers, lakes and ponds. In rivers, it adheres to places with a slow current and considerable depth, as well as in bays, backwaters, oxbow lakes, where there is a sandy-clay bottom with a small admixture of silt. It is most numerous in lakes and in flat areas of rivers. Large individuals keep in the bottom layers of water, deep creeks, pits and in open areas of lakes and reservoirs.

Smaller bream prefers to stay in coastal areas among sparse thickets. At the same time, small individuals usually keep in large flocks. Gustera is characterized by a sedentary lifestyle. In summer, her flocks are small. With the onset of autumn cold weather, they increase and move to the pits. With the onset of spring floods, her flocks go to feeding places.

As the spawning time approaches, after the water warms up, the flocks of the silver bream increase and move to the spawning grounds. At the same time, the lake spawning bream in large numbers goes to the shores, and the river bream, leaving the channel, enters shallow bays and backwaters. Silver bream spawns from the end of April - in May at a water temperature of 12-20 °. With prolonged cold snaps, spawning can be delayed until June.

The spawning of the silver bream is portioned, however, there are females with a one-time spawning. Its spawning occurs amicably, mainly in the evening and in the morning with a short night break. Before spawning, they become bright silver, pectoral and ventral fins acquire an orange tint. Tubercles of a pearl rash appear on the head and upper part of the body of spawning males. Soon after spawning, all mating changes disappear.

In the Dnieper, on the site of the current Kiev reservoir, three-year-old females of the silver bream had an average of 9.5 thousand eggs, six-year-olds had 22 thousand eggs, and three years after the formation of the reservoir, more than 16 thousand eggs were found in three-year-old females, in six-year-olds - more than 80 thousand pieces, i.e., in the conditions of the reservoir, its fertility increased by 2-3 times.

The bream becomes sexually mature at two or three years of age, and in the spawning herd, males mature mainly earlier than females. In the older age groups of the spawning herd, there are significantly fewer males than females. The bream grows slowly. For example, in the lower reaches of the Southern Bug, yearlings had an average body length of 3.3 cm, three-year-olds - 10.2 cm, and six-year-olds - 16.9 cm.

Until puberty, both sexes grow in the same way, but after puberty, the growth of males slows down somewhat. The juveniles of the silver bream in the reservoirs of the Dnieper feed on crustaceans and chironomid larvae. To a lesser extent, it consumes algae, caddisflies, spiders and water bugs. Adult fish feed on higher aquatic plants, worms, mollusks, crustaceans, larvae and pupae of mosquitoes and other insects.

The main feeding grounds for small bream (10-15 cm long) are located mainly in the coastal zone. Large fish feeding mainly on mollusks feed in places more remote from the coast. Fish with a length of 25-32 cm, with significant fatty deposits on the intestines, eat less. With an increase in the size of the body of the silver bream, the number of crustaceans and insect larvae in the composition of its feed decreases, and the number of mollusks increases.

She switches to feeding on mollusks with a body length of 13-15 cm or more. Depending on the composition and development of the food base, the ratio of food organisms in the food composition of fish of the same size is not the same. For example, fish 10-12 cm long in the coastal zone feed mainly on insect larvae, and in more deep places— crustaceans, which corresponds to the distribution of these organisms in reservoirs.

Gustera is widespread in Europe. It is absent in the rivers of the Arctic Ocean and in Central Asia. In the CIS, it lives in the basins of the Baltic, Black, Azov and Caspian Seas. In Ukraine, it lives in the basins of all rivers, excluding the Crimean rivers and mountainous sections of other rivers.

List of fish: whitefish species, muksun, omul and vendace

There are many salmon fish, one of the families is whitefish, a numerous, poorly studied and changeable fish genus. Representatives of this family have a laterally compressed body and a small mouth for their size, which causes a lot of inconvenience to fans of fishing with a bait. The lip of a whitefish often does not withstand the load when it is pulled out of the water, and, breaking off the lip, the fish leaves.

Due to the similarity of the silhouette of the head of a whitefish with the head of a herring, the whitefish is also called a herring, and only the adipose fin clearly indicates their salmon affiliation. Extremely high degree variability of characters still does not allow to establish the exact number of their species: in each lake you can set your own special kind, for example, 43 forms were found only on the lakes of the Kola Peninsula. Currently, work is underway to combine similar forms into one species, which should lead to a systematization of the species of whitefish family.

General description of the family

On the territory of Russia, there are over a hundred varieties of fish of this family, which have excellent taste and other useful properties. Its habitat is almost all water bodies from the Kola Peninsula in the west to the Kamchatka and Chukotka Peninsulas in the east. Although this fish belongs to salmon, its meat is white, sometimes pinkish in color. Often, even experienced anglers do not even suspect that the Baikal omul is the same whitefish. Here is a small enumeration of the names of fish of the whitefish family:

vendace largemouth and European (ripus), whitefish Atlantic and Baltic;
Volkhov, Baunt and Siberian whitefish (pyzhyan), Baikal omul;
muksun, tugun, valamka and chir (shokur).

This diverse fish does not have a single appearance, but all members of the family have uniform silvery scales and darkened fins. The adipose fin, the hallmark of all salmon fish is also a common feature of fish of the whitefish genus. A distinctive feature of females is the scales, unlike the scales of males, it is larger and has a yellowish tint.

Like salmon, whitefish can be found in both fresh and salt water. Depending on this, two groups of sigs are distinguished:

freshwater - lake and river;
migratory or marine whitefish.

Gallery: whitefish species (25 photos)

habits and preferences

A common quality for the whole family is life in a pack, which are formed according to the age of the individuals. Whitefish prefer clear cold water enriched with oxygen, which is usually found in the rapids of rivers and in the depths of lakes. At the same time, a flock of whitefish can drive representatives of other fish species from the pit. As a rule, the larger the fish, the farther it goes from the shore.

The ability to spawn in fish of the family appears at the age of about three years, and in some breeds - a year or two later. Spawning of sea and freshwater whitefish takes place under the same conditions - all of them, including lake ones, rise to the upper reaches of rivers and their tributaries. Spawns whitefish in autumn, when the water gets colder to below five degrees. Places of spawning are deep pits and still waters of rivers, stretches. Here, caviar is aged until spring, when fry appear from caviar with warming water.

The diet of the whitefish family, like all predators, is of animal origin: vertebrate and invertebrate insects (worms, larvae and caterpillars, caddisflies and bark beetles), small crustaceans and mollusks, caviar. Depending on the age and, accordingly, the size of the predator itself, it also attacks fish that are smaller than it. But there are among the whitefish and lovers of vegetarian food collected from the bottom, as well as omnivores - semi-predators.

Their life expectancy is about two decades, but more often half-aged fish are caught. The largest whitefish is usually a little more than half a meter long, and small adult breeds are from one to one and a half decimeters.

As a rule, whitefish are distinguished into separate groups according to the position of the mouth. The mouth can be directed upward - the upper mouth, forward - the terminal, and downward - the lower mouth.

Upper mouth - small fish that feed on what they find near the surface of the water. These are insects and invertebrates - worms and caterpillars. Fish with an upper mouth are represented mainly by the European vendace (ripus) and the larger Siberian vendace. The latter is up to half a meter in length, lives in places where rivers flow into the salty waters of the sea, and almost never occurs in lakes. Ripus is half the size, it is an inhabitant of the lakes. Both types of vendace are commercial.

Whitefish with a mouth in front (final) are also commercial. Omul is a large, over half a meter long fish that lives, like vendace, in the bays of the seas and the mouths of the rivers flowing into the sea, where it rises to spawn. The diet of omul includes crustaceans and small fish. Baikal omul is a lake species of whitefish. Another lake-river species is the peled (cheese) fish, it does not enter sea water, but is as large as vendace and omul, its length is about half a meter. It was also brought to the reservoirs of the Southern Urals, here its dimensions are not so impressive. There is also a small relative of whitefish with a terminal mouth - tugun, which lives in the rivers of Siberia. Its length does not exceed twenty centimeters.

Whitefish with a lower mouth position also live in Russian water bodies, there are seven species of them. But at present, work is underway to separate them, and it makes no sense to provide any information on them.

Freshwater whitefish

Breed river whitefish - by name, an inhabitant of the rivers, where it gets from the sea or a large lake when moving to spawn. Its usual weight is about a kilogram, rarely exceeds two kilograms. In the lakes, the river whitefish only hibernates, in all other seasons it leads a river life. In fact, this is a marine or migratory whitefish acclimatized to river life. The caviar of this type of whitefish is multiple - up to 50 thousand eggs and slightly lighter than trout caviar.

Pechora whitefish, the most famous omul, it has already been mentioned above, peled, whitefish. Peled reaches a length of more than half a meter and a weight of about three kilograms. Chir is much larger, it can weigh up to ten kg, lives in the lakes of the Pechora River basin and its channels.

The Baikal omul reaches a weight of up to seven kilograms, its food is small epishura crustaceans, with an insufficient amount of which it switches to eating small fish. Starting from September, the omul rises into the rivers, preparing for spawning. According to the locations of spawning grounds, subspecies of the Baikal omul are distinguished:

Angarsk - early maturing, maturity at five years, but with slow growth;
selenginsky - maturity at seven years old, growing rapidly;
chivirkuy - also grows rapidly, spawning in October.

The omul finishes spawning when sludge already appears on the river and floats back to Lake Baikal for wintering. At one time, the fish was intensively caught by commercial fishermen, and its number has significantly decreased, but now measures are being taken for the artificial reproduction of omul.