The value of the soft color of female fish. Cave fish and fish coloration. What determines the color of fish
The color of fish can be surprisingly diverse, but all possible shades of their color are due to the work of special cells called chromatophores. They are found in a specific layer of the fish's skin and contain several types of pigments. Chromatophores are divided into several types. Firstly, these are melanophores containing a black pigment called melanin. Further, etitrophores, containing red pigment, and xanthophores, in which it is yellow. The latter type is sometimes called lipophores because the carotenoids that make up the pigment in these cells are dissolved in lipids. Guanophores or iridocytes contain guanine, which gives the color of fish a silvery color and metallic luster. The pigments contained in chromatophores differ chemically in terms of stability, solubility in water, sensitivity to air, and some other features. The chromatophores themselves are also not the same in shape - they can be either stellate or rounded. Many colors in the coloration of fish are obtained by imposing some chromatophores on others, this possibility is provided by the occurrence of cells in the skin on different depth. For example, green color is obtained when deep-lying guanophores are combined with xanthophores and erythrophores covering them. If you add melanophores, the body of the fish acquires Blue colour.
Chromatophores do not have nerve endings, with the exception of melanophores. They are even involved in two systems at once, having both sympathetic and parasympathetic innervation. Other types of pigment cells are controlled humorally.
The color of fish is quite important for their life. Coloring functions are divided into patronizing and warning. The first option is designed to mask the body of the fish in environment, so usually this coloration consists of soothing colors. Warning coloring, on the contrary, includes a large number of bright spots and contrasting colors. Its functions are different. In poisonous predators, which usually say with the brightness of their body: “Don’t come near me!”, It plays a deterrent role. Territorial fish guarding their home are brightly colored in order to warn the rival that the place is occupied and to attract the female. A kind of warning coloration is also the marriage attire of fish.
Depending on the habitat, the body color of the fish acquires characteristic features that make it possible to distinguish pelagic, bottom, thicket and schooling colors.
Thus, the color of fish depends on many factors, including habitat, lifestyle and nutrition, season, and even the mood of the fish.
If you find an error, please highlight a piece of text and click Ctrl+Enter.
The morphological side of the coloration of fish has been described earlier. Here we will analyze environmental significance coloring in general and its adaptive value.
Few animals, not excluding insects and birds, can compete with fish in the brightness and variability of their coloration, which disappears for them for the most part with death and after being placed in a preservative liquid. Painted so varied only bony fish(Teleostei), which have all the methods of color formation in various combinations. Stripes, spots, ribbons are combined on the main background, sometimes in a very complex pattern.
In the coloration of fish, as well as other animals, many see in all cases an adaptive phenomenon, which is the result of selection and gives the animal the opportunity to become invisible, hide from the enemy, and lie in wait for prey. In many cases this is certainly true, but not always. AT recent times there are more and more objections to such a one-sided interpretation of the coloration of fish. A number of facts speak for the fact that coloration is a physiological result, on the one hand, of metabolism, on the other, of the action of light rays. Coloration arises from this interaction and may have no protective value at all. But in those cases where coloration can be ecologically important, when coloration is supplemented by the corresponding habits of fish, when it has enemies from which it is necessary to hide (and this is not always the case in those animals that we consider to be protectively colored), then coloration becomes a tool in the struggle for existence, is subject to selection and becomes an adaptive phenomenon. Coloring can be useful or harmful not in itself, but being correlated with some other useful or harmful feature.
AT tropical waters ah, and metabolism and light are more intense. And the coloring of animals is brighter here. In the colder and less brightly illuminated waters of the north, and even more so in caves or underwater depths, the color is much less bright, sometimes even scooping.
The need for light in the production of pigment in the skin of fish is supported by experiments with flounders kept in aquariums in which the underside of the flounder was exposed to light. On the latter, a pigment gradually developed, but usually the underside of the body of the flounder is white. Experiments were made with young flounders. Pigmentation developed the same as on the upper side; if the flounders were kept in this way for a long time (1-3 years), then the underside became exactly the same pigmented as the top. This experiment, however, does not contradict the role of selection in the development of protective coloration - it only shows the material from which, due to selection, the flounder has developed the ability to respond to the action of light by forming a pigment. Since this ability could be expressed to the same extent in different individuals, selection could act here. As a result, in flounders (Pleuronoctidae) we see a pronounced changeable protective coloration. In many flounders upper surface the body is painted in various shades of brown with black and light spots and is in harmony with the prevailing tone of the sandbars on which they usually feed. Once on the ground of a different color, they immediately change their color to the color corresponding to the color of the bottom. Experiments with the transfer of flounders to soils painted like a chessboard with squares of various sizes gave a striking picture of the animal acquiring the same pattern. It is very important that some fish that change in different times habitat, adapt in their color to new conditions. For example, Pleuronectes platessa in summer months rests on clean light sand and is lightly colored. In the spring, after spawning, R. platessa, having changed color, is looking for silty soil. The same choice of habitat corresponding to coloration, more precisely, the appearance of a different coloration in connection with a new habitat, is also observed in other fish.
Fish living in transparent rivers and lakes, as well as fish in the surface layers of the sea, have common type coloration: the back, they are colored dark, mostly blue, and the ventral side is silvery. It is generally accepted that the dark blue color of the spoke makes the fish invisible to aerial enemies; the lower one - silvery - against predators, who usually stay at a greater depth and can notice the fish from below. Some believe that the silvery-shiny coloration of the belly of fish from below is invisible. According to one opinion, rays reaching the surface of the water from below at an angle of 48° (in salt water 45°) are entirely reflected from the dog. The position of the eyes on the fish's head is such that they can see the surface of the water at a maximum angle of 45°. Thus, only reflected rays enter the eyes of the fish, and the surface of the water appears to the fish as silver-shiny, like the bottom and sides their prey, which for this reason becomes invisible. According to another opinion, the mirror surface of the water reflects the bluish, greenish and brown tops of the entire reservoir, the silvery belly of the fish does the same. The result is the same as in the first case.
However, other researchers believe that the above interpretation of the white or silver color of the belly is incorrect; that her useful value nothing has been proven for fish; that the fish is not attacked from below and that it must appear dark and conspicuous from below. The white color of the ventral side, in this opinion, is a simple consequence of the absence of its illumination. However specific feature a trait can become only if it is directly or indirectly useful biologically. Therefore, simplified physical explanations are hardly justified.
In fish living at the bottom of the reservoir, the upper surface of the body is dark, often decorated with sinuous stripes, larger or smaller spots. The ventral side is gray or whitish. Such bottom fish include palima (Lota lota), minnow (Gobio fluviatilis), goby (Cottus gobio), catfish (Siluris glanis), loach (Misgurnus fossilis) - from freshwater, sturgeon (Acipenseridae), and from purely marine - marine devil (Lophius piscatorius), stingrays (Batoidei) and many others, especially flounders (Pleuronectidae). In the latter, we see a sharply pronounced changeable protective coloration, which was mentioned above.
We see another type of color variability when fish of the same species become darker in deep water with a muddy or peaty bottom (lake) and lighter in shallow and clear water. An example is the trout (Salmo trutta morpha fario). Trout from gravel or sandy bottom streams are lighter in color than those from muddy streams. Vision is necessary for this color change. We are convinced of this by experiments with transection of the optic nerves.
A striking example of protective coloration is australian view seahorse- Phyllopteryx eques, in which the skin forms numerous, long, flat, branched filaments, colored with brown and orange stripes, like the algae among which the fish lives. Many fish living among the coral reefs of the Indian and Pacific Oceans, especially fish belonging to the Ohaсtodontidae and Pomacentridae families, have in the highest degree brilliant and lively coloration, often decorated with stripes of various colors. In both named families, the same color pattern developed independently. Even the reef-visiting flounders, which are usually dull in color, have the upper surface adorned with lively tops and striking patterning.
Coloring can be not only protective, but also help the predator to be invisible to its prey. Such, for example, is the striped coloration of our perch and pike, and perhaps zander; dark vertical stripes on the body of these fish make them invisible among plants, where they wait for prey. In connection with this coloration, many predators develop special processes on the body that serve to lure prey. Such, for example, is the sea devil (Lophius piscatorius), painted patronizingly and having a front ray dorsal fin modified into a tendril, movable thanks to special muscles. The movement of this antenna deceives the small fishes, mistaking it for a worm and approaching to disappear into the mouth of Lophius.
It is quite possible that some cases of bright coloration serve as warning coloration in fish. Such, probably, is the brilliant coloration of many symtognathic (Plectognathi). It is associated with the presence of prickly spines that can bulge, and can serve as an indication of the danger of attacking such fish. The meaning of warning coloration, perhaps, has a bright color sea dragon(Trachinus draco), armed with poisonous spikes on the gill cover and a large spine on the back. Perhaps, some cases should be attributed to the phenomena of an adaptive nature. complete disappearance coloration in fish. Many pelagic larvae of Teleostei lack chromatophores and are colorless. Their body is transparent, and therefore hardly noticeable, just as glass lowered into the water is hardly noticed. Transparency increases due to the absence of hemoglobin in the blood, as, for example, in Leptocephali - eel larvae. Larvae of Onos (family Gadidae) during the pelagic period of their life have a silver color due to the presence of iridocytes in the skin. Ho, passing with age to life under stones, they lose their silver luster and acquire a dark color.
Many secrets and mysteries of nature still remain unsolved, but every year scientists discover more and more new species of previously unknown animals and plants.
Thus, snail worms were recently discovered, whose ancestors lived on Earth over 500 million years ago; scientists also managed to catch a fish that was previously thought to have died out 70 million years ago.
This material is dedicated to the extraordinary, mysterious and yet unexplained phenomena ocean life. Learn to understand the complex and varied relationships between the inhabitants of the ocean, many of which have lived in its depths for millions of years.
Lesson type: Generalization and systematization of knowledge
Target: development of erudition, cognitive and creative abilities of students; formation of the ability to search for information to answer the questions posed.
Tasks:
Educational: shaping cognitive culture, mastered in the process of educational activity, and aesthetic culture as the ability to have an emotional and valuable attitude towards objects of wildlife.
Developing: development of cognitive motives aimed at obtaining new knowledge about wildlife; cognitive qualities of the individual associated with the assimilation of the basics scientific knowledge, mastering the methods of studying nature, the formation of intellectual skills;
Educational: orientation in the system of moral norms and values: recognition high value life in all its manifestations, health of one's own and other people; ecological consciousness; education of love for nature;
Personal: understanding of responsibility for the quality of acquired knowledge; understanding the value of an adequate assessment of one's own achievements and capabilities;
cognitive: the ability to analyze and evaluate the impact of environmental factors, risk factors on health, the consequences of human activities in ecosystems, the impact of one's own actions on living organisms and ecosystems; focus on continuous development and self-development; ability to work with various sources information, convert it from one form to another, compare and analyze information, draw conclusions, prepare messages and presentations.
Regulatory: the ability to organize independently the execution of tasks, evaluate the correctness of the work, reflection of their activities.
Communicative: the formation of communicative competence in communication and cooperation with peers, understanding the characteristics of gender socialization in adolescence, socially useful, educational and research, creative and other types of activities.
Technology: Health saving, problematic, developmental education, group activities
Lesson structure:
Conversation - reasoning about previously acquired knowledge on a given topic,
Watching video (movie),
Topic «
« What determines the color of fish?
Presentation "What determines the color of fish"
The inhabitants of the sea are among the most brightly colored creatures in the world. Such organisms, shimmering with all the colors of the rainbow, live in the sun-drenched waters of warm tropical seas.
Coloring of fish biological significance.
Coloration is of great biological importance for fish. There are protective and warning colors. The protective coloration is intended to camouflage the fish against the background of the environment. Warning, or sematic, coloration usually consists of conspicuous large, contrasting spots or bands that have clear boundaries. It is intended, for example, in poisonous and poisonous fish, to prevent a predator from attacking them, and in this case it is called a deterrent.
Identification coloration used to warn a rival in territorial fish, or to attract females to males by warning them that the males are ready to spawn. The last type of warning coloration is commonly referred to as the mating dress of fish. Often the identification coloration unmasks the fish. It is for this reason that in many fish guarding the territory or their offspring, the identification coloration in the form of a bright red spot is located on the belly, shown to the opponent if necessary, and does not interfere with the masking of the fish when it is located belly to the bottom. There is also a pseudosematic coloration that mimics the warning coloration of another species. It is also called mimicry. It allows harmless fish species to avoid being attacked by predators who mistake them for dangerous view.
What determines the color of fish?
The color of fish can be surprisingly diverse, but all possible shades of their color are due to the work of special cells called chromatophores. They are found in a specific layer of the fish's skin and contain several types of pigments. Chromatophores are divided into several types.
First, these are melanophores containing a black pigment called melanin. Further, etitrophores, containing red pigment, and xanthophores, in which it is yellow. The latter type is sometimes called lipophores because the carotenoids that make up the pigment in these cells are dissolved in lipids. Guanophores or iridocytes contain guanine, which gives the color of fish a silvery color and metallic luster. The pigments contained in chromatophores differ chemically in terms of stability, solubility in water, sensitivity to air, and some other features. The chromatophores themselves are also not the same in shape - they can be either stellate or rounded. Many colors in the coloration of fish are obtained by superimposing some chromatophores on others, this possibility is provided by the occurrence of cells in the skin at different depths. For example, a green color is obtained when deep-lying guanophores are combined with xanthophores and erythrophores covering them. If you add melanophores, the body of the fish becomes blue.
Chromatophores do not have nerve endings, with the exception of melanophores. They are even involved in two systems at once, having both sympathetic and parasympathetic innervation. Other types of pigment cells are controlled humorally.
The color of fish is quite important for their life.. Coloring functions are divided into patronizing and warning. The first option is designed to mask the body of the fish in the environment, so usually this coloration consists of soothing colors. Warning coloring, on the contrary, includes a large number of bright spots and contrasting colors. Its functions are different. In poisonous predators, which usually say with the brightness of their body: “Don’t come near me!”, It plays a deterrent role. Territorial fish guarding their home are brightly colored in order to warn the rival that the place is occupied and to attract the female. A kind of warning coloration is also the marriage attire of fish.
Depending on the habitat, the body color of the fish acquires characteristic features that make it possible to distinguish pelagic, bottom, thicket and schooling colors.
Thus, the color of fish depends on many factors, including habitat, lifestyle and nutrition, season, and even the mood of the fish.
Identification coloration
In the waters around the coral reefs, which are teeming with all sorts of life forms, each species of fish has its own identification paint, similar to the uniforms of football players of one team. This allows other fish and individuals of the same species to instantly recognize it.
The coloring of the dogfish becomes brighter when it seeks to attract a female.
Dogfish - deadly dangerous predator
Dog fish belongs to the order of pufferfish or pufferfish, and there are more than ninety species of them. It differs from other fish unique ability swell up when frightened, swallowing a large volume of water or air. At the same time, she pricks with spikes, spewing out a nerve poison called tetrodotoxin, which is 1200 times more effective. potassium cyanide
dog-fish from behind special structure teeth is called puffer. Puffer teeth are very strong, fused together, and look like four plates. With their help, she splits the shells of mollusks and crab shells, getting food. A rare case is known when live fish, not wanting to be eaten, bit off the cook's finger. Some species of fish are also able to bite, but the main danger is its meat. In Japan, this exotic fish is called fugu, skillfully cooked, it is at the top of the list of local cuisine delicacies. The price for one serving of such a dish reaches $ 750. When an amateur chef takes over its preparation, the tasting ends lethal outcome, because in the skin and in internal organs This fish contains the strongest poison. First, the tip of the tongue goes numb, then the limbs, followed by convulsions and instant death. When gutting the fish, the dog emits a fetid, eerie odor.
The coloring of the Moorish idol fish is most striking when it hunts its prey.
The main body color is white. The edge of the upper jaw is black. The lower jaw is almost completely black. In the upper part of the muzzle there is a bright orange spot with a black border. There is a wide black stripe between the first dorsal fin and the ventral fin. Two thin, curved bluish stripes run from the first black stripe, from the beginning of the pelvic fins to the anterior part of the dorsal fin, and from abdominal cavity to the base of the dorsal fin. The third, less noticeable, bluish stripe is located from the eyes towards the back. The second, gradually expanding, wide black stripe is located from the dorsal rays in the direction of the ventral ones. Behind the second wide black stripe is a thin vertical white line. A bright yellow-orange spot with a thin white border extends from the tail to the middle of the body, where it gradually merges with the main white color. The caudal fin is black with white trim.
Day and night coloring
At night, the fusilier fish sleeps on seabed, taking on a dark color that matches the color of the sea depths and bottom. Waking up, it brightens and becomes completely light as it approaches the surface. By changing color, it becomes less noticeable.
awake fish
Waking up fish
sleeping fish
Warning coloration
Seeing from afar brightly colored harlequin toothfish”, other fish immediately understand that this hunting area is already occupied.
Warning coloration
The bright coloring warns the predator: beware, this creature tastes bad or is poisonous! Pointy-nosed pufferfish extremely poisonous, and other fish do not touch it. In Japan, this fish is considered edible, but when cutting it, an experienced connoisseur must be present to remove the poison and make the meat harmless. And yet this fish, called fugu and considered a delicacy, claims the lives of many people every year. So, in 1963, viper fish were poisoned by meat and 82 people died.
The puffer fish is not at all scary in appearance: it is only the size of a palm, swims with its tail forward, very slowly. Instead of scales - thin elastic skin, capable of inflating in case of danger to a size three times larger than the original - a kind of goggle-eyed, outwardly harmless ball.
However, her liver, skin, intestines, caviar, milk, and even her eyes contain tetrodoxin, a strong nerve poison, 1 mg of which is a lethal dose for humans. There is no effective antidote for it yet, although the poison itself, in microscopic doses, is used to prevent age-related diseases, as well as to treat diseases. prostate.
Multicolor Mystery
Most starfish move very slowly and live on clean bottoms, not hiding from enemies. Faded, muted tones would help them to become invisible, and it is very strange that the stars have such a bright color.
Depending on the habitat, the body color of the fish acquires characteristic features that make it possible to distinguish pelagic, bottom, thicket and schooling coloration.
Pelagic fish
The term "pelagic fish" comes from the place in which they live. This area is the area of the sea or ocean, which does not border the bottom surface. Pelageal - what is it? From the Greek "pelagial" is interpreted as "open sea", which serves as a habitat for nekton, plankton and pleuston. Conventionally, the pelagic zone is divided into several layers: epipelagic - located at a depth of up to 200 meters; mesopelagial - at a depth of up to 1000 meters; bathypelagial - up to 4000 meters; over 4000 meters - abyspelagial.
Popular types
The main commercial catch of fish is pelagic. It accounts for 65-75% of the total catch. Due to the large natural supply and availability, pelagic fish are the most inexpensive type of seafood. However, this has no effect on palatability and utility. The leading position of the commercial catch is occupied by pelagic fish of the Black Sea, the North Sea, the Sea of Marmara, the Baltic Sea, as well as the seas of the North Atlantic and the Pacific basin. These include smelt (capelin), anchovy, herring, herring, horse mackerel, cod (blue whiting), mackerel.
bottom fish- most life cycle carried out at the bottom or in close proximity to the bottom. They are found both in coastal regions of the continental shelf and in the open ocean along the continental slope.
Bottom fish can be divided into two main types: purely bottom and benthopelagic, which rise above the bottom and swim in the water column. In addition to the flattened shape of the body, an adaptive feature of the structure of many bottom-dwelling fish is the lower mouth, which allows them to feed from the ground. Sand sucked in with food is usually ejected through gill slits.
overgrown coloring
Overgrown painting- brownish, greenish or yellowish back and usually transverse stripes or stains on the sides. This coloration is characteristic of fish in thickets or coral reefs. Sometimes these fish, especially in tropical zone, can be colored very brightly.
Examples of fish with overgrown coloration are: common perch and pike - from freshwater forms; sea scorpion ruff, many wrasses and coral fish- from the sea.
Vegetation, as an element of the landscape, is also important for adult fish. Many fish are specially adapted to life in thickets. They have a corresponding protective coloration. or a special form of the body, reminiscent of ts zardeli, among which the fish lives. So, the long outgrowths of the fins of the rag-picker seahorse, in combination with the corresponding color, make it completely invisible among the underwater thickets.
flock coloring
A number of features in the structure are also associated with a schooling lifestyle, in particular the color of fish. Schooling coloration helps fish to orient themselves to each other. In those fish in which a schooling lifestyle is characteristic only of juveniles, accordingly, schooling coloration can also appear.
A moving flock is different in shape from a stationary one, which is associated with the provision of favorable hydrodynamic conditions for movement and orientation. The shape of the moving and stationary flock is different in different types fish, np can be different in the same species. A moving fish forms a certain force field around its body. Therefore, when moving in a flock, fish adjust to each other in a certain way. Flocks are grouped from fish usually of close sizes and a similar biological state. Fish in a flock, unlike many mammals and birds, apparently do not have a permanent leader, and they alternately focus either on one or the other of their member, or, more often, on several fish at once. Fish navigate in a flock with the help, first of all, of the organs of vision and the lateral line.
Mimicry
One of the adaptations is color change. Flat fish are masters of this miracle: they can change color and its pattern in accordance with the pattern and color of the seabed.
Presentation Hosting
Fish coloring
The color of the fish is very diverse. AT Far Eastern waters inhabited by small (8–10 centimeters), smelt-like noodle fish with a colorless, completely transparent body: the insides are visible through the thin skin. Near the seashore, where the water so often foams, the herds of this fish are invisible. Seagulls manage to eat "noodles" only when the fish jump out and appear above the water. But the same whitish coastal waves that protect the fish from birds often destroy them: on the shores you can sometimes see whole shafts of fish noodles thrown out by the sea. It is believed that after the first spawning, this fish dies. This phenomenon is characteristic of some fish. So cruel nature! The sea throws out both living and “noodles” that died of natural death.
Since fish noodles are usually found in large herds, they should have been used; in part, it is still mined.
There are other fish with a transparent body, for example, the deep-sea Baikal golomyanka, which we will discuss in more detail below.
At the far eastern tip of Asia, in the lakes of the Chukchi Peninsula, there is a black dallium fish.
Its length is up to 20 centimeters. The black coloration makes the fish unobtrusive. Dallium lives in peaty dark-water rivers, lakes and swamps, buries itself in wet moss and grass for the winter. Outwardly, dahlia looks like common fish, but it differs from them in that its bones are tender, thin, and some are completely absent (there are no infraorbital bones). But this fish has highly developed pectoral fins. Do not fins such as shoulder blades help fish burrow into the soft bottom of the reservoir in order to survive in the winter cold?
Brook trout are colored with black, blue and red spots of various sizes. If you look closely, you can see that the trout changes its clothes: during the spawning period, it is dressed in a particularly flowery “dress”, at other times - in more modest clothes.
The small minnow fish, which can be found in almost every cool stream and lake, has an unusually variegated color: the back is greenish, the sides are yellow with gold and silver reflections, the abdomen is red, yellowish fins are with a dark rim. In a word, the minnow is small in stature, but he has a lot of force. Apparently, for this he was nicknamed "buffoon", and such a name is perhaps more just than "minnow", since the minnow is not at all naked, but has scales.
The most brightly colored fish are marine, especially tropical waters. Many of them can successfully compete with birds of paradise. Look at table 1. There are no flowers here! Red, ruby, turquoise, black velvet... They are surprisingly harmoniously combined with each other. Curly, as if honed by skilled craftsmen, the fins and body of some fish are decorated with geometrically regular stripes.
In nature, among corals and sea lilies, these colorful fish are a fabulous picture. Here is what the famous Swiss scientist Keller writes about tropical fish in his book Life of the Sea: “The fish of the coral reefs are the most elegant sight. Their colors are not inferior in brightness and brilliance to coloring. tropical butterflies and birds. Azure, yellowish green, velvety black and striped fish flicker and curl in whole crowds. You involuntarily take hold of the net to catch them, but... one blink of an eye - and they all disappear. With a laterally compressed body, they can easily penetrate the cracks and crevices of coral reefs.
The well-known pikes and perches have greenish stripes on their bodies, which mask these predators in the grassy thickets of rivers and lakes and help them approach their prey unnoticed. But the pursued fish (bleak, roach, etc.) also have a protective coloration: the white belly makes them almost invisible when viewed from below, the dark back is not striking when viewed from above.
Fish living in the upper layers of the water have a more silvery color. Deeper than 100–500 meters there are red fish ( sea bass), pink (liparis) and dark brown (pinagore) flowers. At depths exceeding 1000 meters, the fish are predominantly dark in color (anglerfish). In the area of ocean depths, more than 1700 meters, the color of the fish is black, blue, purple.
Table 1. tropical water fish
The color of the fish largely depends on the color of the water and the bottom.
AT clear waters bersh, which is usually gray in color, is distinguished by whiteness. Against this background, dark transverse stripes stand out especially sharply. In shallow swampy lakes, perch is black, and in rivers flowing from peat bogs, blue and yellow perch are found.
Volkhov whitefish, which was once in large numbers lived in the Volkhov Bay and the Volkhov River, which flows through limestone, differs from all Ladoga whitefish in light scales. According to it, this whitefish is easy to find in the total catch of Ladoga whitefish. Among the whitefish of the northern half of Lake Ladoga, black whitefish are distinguished (in Finnish it is called “musta siyka”, which means black whitefish in translation).
The black color of the northern Ladoga whitefish, like the light Volkhov one, remains quite stable: the black whitefish, finding itself in southern Ladoga, does not lose its color. But over time, after many generations, the descendants of this whitefish, who remained to live in southern Ladoga, will lose their black color. Therefore, this feature may vary depending on the color of the water.
After low tide, the flounder remaining in the coastal gray mud is almost completely invisible: grey colour her back merges with the color of silt. The flounder did not acquire such a protective coloration at the moment when it found itself on a dirty shore, but inherited it from its near and distant ancestors. But fish are capable of changing color very quickly. Put a minnow or other brightly colored fish in a black-bottomed tank and after a while you will see that the color of the fish has faded.
There are many surprising things in the coloring of fish. Among the fish that live at depths where even a weak ray of the sun does not penetrate, there are brightly colored ones.
It also happens like this: in a flock of fish with a color common to a given species, individuals of white or black color come across; in the first case, the so-called albinism is observed, in the second - melanism.