External structure of flounder. Flounder fish - flat bottom dweller
Flounder is a special genus of fish in the flounder family. Moreover, there are river and sea flounder; they live in seas and rivers, respectively. This is a very amazing fish, because it has a flattened body that is turned on its side.
Description and varieties
All flounders have a flat body. The lower part is one of the sides of the fish, which has moved as a result of undergoing metamorphosis, which is characteristic of all flatfishes. The lower part can be compared to sandpaper: it is very rough from constant contact with the bottom of the reservoir, there are no eyes here. The eye on this side moves to the other, since it is bad to observe what is happening with one eye.
The upper part of the fish contains the pectoral fins. There is also an eye that has moved from the bottom side. Flounder has a pigment that allows it to imitate any surface. This is necessary for the fish in order to hide at the bottom from predators who like to feast on it. If you put a flounder on a chessboard, then light and dark spots will certainly appear on the top, like on the board.
There are two main types of flounder: river flounder and sea flounder. Externally, the fish are very similar to each other, but they may differ in size and body weight. There is a wide variety of flounder species within the genus, but the largest one is caught at sea. She weighed more than a hundredweight, and her body length was 2 meters. River flounder grows up to 50 centimeters and reaches a weight of 2 kilograms, and sea flounder grows up to 60 centimeters and weighs 7 kilograms. But in the photo they look about the same.
Of course, everyone who sees this type of fish for the first time is interested in the question: why is flounder flat? This is necessary in order to lead a benthic lifestyle and burrow into the ground as much as possible, imitating its structure, otherwise the fish will serve as food for predators. The young flounder swims vertically, and its appearance is normal, familiar to us. However, as the fish grows older, it undergoes a metamorphosis, and it already swims sideways, and all parts of the body are displaced for a more convenient existence.
Distribution and habitats
Marine and river flounder species have different habitats. Marine fish live mainly in the waters of the Atlantic Ocean. But it is also common in the White, Northern and Okhotsk Seas. River flounder can live both in the sea and in rivers, where they can swim quite far. This fish lives in the Black and Mediterranean Seas, in the rivers flowing into them, as well as in the Yenisei. There is even a special type of flounder: Black Sea flounder.
Black Sea flounder is shown in the photo. It is a valuable game fish that fishermen love to hunt. Black Sea flounder, like any other, prefers to lead a bottom-dwelling lifestyle. It is preferable for her that the soil be loose enough to burrow into it easily. But thanks to the ability of mimicry, this is not so important: how many colored stones there are on the bottom, the number of colors will be conveyed by the upper surface of the fish.
Diet
Flounder feeds very variedly. It can be classified as a predatory fish. The basis of nutrition consists of worms, mollusks and small crustaceans. But small fish that swim near the shelter are also often eaten. The fish does not like to leave it, so as not to become prey itself. The photo shows how she jumps up to catch passing prey.
Despite the fact that flounder is a predator, fishermen prefer to use natural bait. To do this, they take worms or shellfish meat. For a fish to pay attention to its potential prey, it must be right under its nose. Otherwise, she is unlikely to come out of hiding, even to eat.
Reproduction
Flounder breeds between February and May. This variation in timing is due to the fact that the habitat is quite wide, and in each case the fish has its own period of time when active spawning occurs. Despite the fact that flounder prefers to live alone, it gathers in schools for spawning. Sometimes several varieties of flounder mix in schools, and then crossing of different species can occur.
Flounder reaches sexual maturity at 3-4 years. During the spawning period, it spawns from several hundred to several million eggs. The amount of caviar depends on the type and size of the fish. The eggs survive an incubation period of 11 days, after which the fry hatch. The fry's left eye is on the left side, and the right eye is on the right: everything is like in ordinary fish.
After hatching, the fry feed on zooplankton, and as they grow, they feed on more nutritious food. Gradually the left side turns into the lower part, from which the eye moves to the right side. Very rarely the right side becomes the lower part. What this is connected with is still unknown to science.
Flounder is a very strange fish that has had to go through a long evolutionary path. Thanks to its features, it is almost invisible on the bottom, but experienced fishermen can force it to grab the hook by teasing the “bottom” with a tasty bait.
physical characteristics
- Length up to 50 cm.
- Weight up to 3 kg.
The body of flounder is flattened. Both eyes are placed on the same side. This side faces up. Almost all flounders have eyes located on the right side of the body. The upper side of the body is better organized than the lower side - the skeleton is better developed here, there are fins, and a brighter color. The pectoral fins of flounders are located on both sides of the body, one of them points up and the other points down. The gills located behind the head are the same on both sides of the body, but one gill cover opens upward and the other opens downward.
Habitat
- Habitat: off the coast of Scandinavia, Central Europe and the Mediterranean Sea from the high tide line to a depth of 55 m, as well as in estuaries and some lakes off the coast.
River flounder is one of the most numerous species of flounder; it also adapts better than other species to new environmental conditions. It is found from the Arctic coast of northern Norway to areas of shallow, sun-warmed water off the coast of North Africa. Can live in both sea and fresh water. River flounder is often found in brackish waters of sea bays. The tidal waters lift the fish upstream where they find rich food sources.
Lifestyle
- Habits: They stay solitary, but gather in large groups on spawning grounds.
River flounder is perfectly adapted to life in freshwater bodies and in the sea. As a rule, it “lies on its side” in sand or silt. At the same time, it exhales water through gills located on the upper side of the body. She often uses her amazing gill structure to hide from the enemy. Having collected water and released it through the gill cover located below, the fish can quickly push off from the bottom.
The best protection for river flounder is the ability to change color and adapt to the surrounding world. Under normal conditions, the upper parts of the flounder's body are brown, with yellow, brown or black speckles. The underside of the flounder's body is white, less often white with brown spots. If necessary, flounder changes color and can acquire the color of sand or bottom silt and even become covered with spots, becoming like pebbles. The color changes over the course of several days, so the fish buries itself in the sand to better camouflage itself. When a flounder swims, it makes an up and down wave-like motion with its flat body. The dorsal and pelvic fins may also be involved in movement.
Nutrition
- Food: molluscs, crustaceans, worms and other animals.
The river flounder has very strong teeth, and thanks to this it can feed on animals that have a hard shell. These animals are an important part of her menu. Flounder's favorite food is hearts, but it does not disdain crabs and worms. Most of the animals that flounder feed on live in large numbers in sand or bottom mud. During low tide, they bury themselves in the sand and emerge from their shelter only when the tide begins. Small crustaceans, benthos and juvenile fish - the main food of flounder - feed on plankton. A lot of plankton floats in coastal waters. River flounder swimming upstream also find rich food sources.
Life cycle
- Puberty: from 3-4 years.
- Spawning: from February to May (depending on water temperature).
- Caviar: up to 2 million eggs.
- Incubation period: 11 days.
River flounder lives and feeds in fresh water, but it breeds in the sea. Spawning occurs at a depth of 25-40 m, and the eggs released into the water first float in the water column, and before metamorphosis they sink to the bottom; the fry hatched from the eggs remain at the surface, where they feed on small planktonic organisms. After hatching, the eyes of the flounder are still located on both sides of the head. Flounder larvae have the same symmetrical body structure as other fish. The grown fish lies on its side on the seabed. Around this time, the flounder's left eye moves to the top side of its head. The upper side of the fish's body darkens, then the juveniles release air from the swim bladder and sink to the bottom. In late spring they find refuge in river shallows.
Related species
A subspecies of river flounder is the Baltic river flounder ( Platichthys flesus trachurus), other related species are the sole ( Pleuronectes platessa) and Atlantic halibut ( Hippoglossus hippoglossus).
- The upper side of the body of the flounder contains a special pigment, so the fish can change color and adapt to any soil. When placed on a checkerboard, it also tries to adapt to the background and forms light and dark spots on the body.
- Most flounder lie on the left side of the body. However, sometimes there are “inverted” individuals lying on their right side.
- Sometimes river flounder crosses with other species of fish from the flounder family. Such offspring develop features of both parents.
- Adult river flounder often travel vast distances to get to their spawning grounds. During such a journey, they lose up to 10% of their mass.
see also
Literature
- Magazine "In the World of Wildlife", No. 13, September 12, 2008
Links
Wikimedia Foundation.
2010.
See what “River flounder” is in other dictionaries:
Pacific river flounder Baltic river flounder
- Baltijos upinė plekšnė statusas T sritis zoologija | vardynas taksono rangas rūšis atitikmenys: lot. Platichthys flesus trachurus rus. Baltic river flounder ryšiai: platesnis terminas – upinės plekšnės … Žuvų pavadinimų žodynas European river flounder
- europinė upinė plekšnė statusas T sritis zoologija | vardynas taksono rangas rūšis atitikmenys: lot. Platichthys flesus flesus angl. European flounder; fluke; mud flounder rus. European river flounder ryšiai: platesnis terminas – upinės… … Žuvų pavadinimų žodynas
Star flounder ... Wikipedia star flounder
- žvaigždėtoji upinė plekšnė statusas T sritis zoologija | vardynas taksono rangas rūšis atitikmenys: lot. Platichthys stellatus angl. California flounder; great flounder; starry flounder eng. star flounder; Pacific river flounder ryšiai … Žuvų pavadinimų žodynas This group includes the largest number of commercial flounders; it is the most numerous and practically important. It contains about 28 genera and 60 species, while the remaining subfamilies taken together include only... ...
Biological encyclopedia
The first place among flounders among our fishermen is rightly occupied by the sea flounder (Pleuronectes platessa). Its length only in rare cases exceeds 60 cm, and its weight only in exceptional cases reaches 7 kg. Being, depending on... ...Animal life
Flounder Morska ... Wikipedia- (Hippoglossus hippoglossus) see also FLOUSTER FAMILY (PLEURONECTIDAE) The elongated body of the Atlantic halibut is covered with medium-sized rounded scales, each larger scale is surrounded by a ring of small additional scales. Both eyes... ... Pisces of Russia. Directory
Species and individuals of flounder-like fish are especially numerous, inhabiting the seas of the temperate and tropical zones; towards the north the number of species decreases rapidly; in British waters, according to Yarrell, 16 species of these fish were found, in Kattegat so far... ... Animal life
Flounder is a fish that is both common and quite exotic. Representatives of the flounder family are quite widespread in the seas of the Northern Hemisphere - from the Baltic to the Azov, and are well known to fishermen and lovers of fish cuisine. Many types of flounder have very tasty and tender meat.
At the same time, flounder is a fish that invariably attracts attention on the store counter due to the unique structure of its body, “flattened” in the horizontal plane. Let's figure out what features this inhabitant of the sea and river bottom has.
Flounder belongs to the class of ray-finned fish, order Flatfish, family of flounder. There are about 60 species, most of which are right-sided. Some individual varieties, for example, the Black Sea flounder (aka kalkan) are left-sided, or reverse.
This division comes from a specific feature of flounders, their unique body structure, which makes it possible to unambiguously identify this fish. It is asymmetrical. The flounder constantly “lies on its side,” usually on the left, while its left eye shifts to the right, upper side. The gill cover and pectoral fin remain on the lower one (in some minor species it may be reduced).
During the period of growing up, representatives of this family seem to go through the entire cycle of evolution. In the first year of life, the fry are quite symmetrical, like ordinary pelagic fish. In the second year they go to the bottom, and the structure of the body, including the skeleton, changes very quickly. The left eye (in left-sided species, the right eye) moves to the upper side, the location of the internal organs changes, and the skin metamorphoses. The upper part acquires a dark, mucus-covered skin, the lower part remains white or light yellow. It has a rough, fairly durable surface that protects fish from sharp stones and other objects on the bottom.
Photo 1. Metamorphosis close-up.
Different species of this fish have a length from 30 cm (yellowfin flounder, which is found near the coast of Kamchatka) to 4.7 m (Atlantic halibut). The average length of representatives of the most common commercial species is 40-50 cm; due to active fishing of juveniles, it is constantly decreasing.
Types of flat bottom dwellers
The main commercial species hunted for tasty meat include:
- river or Baltic flounder;
- yellow-bellied flounder;
- Black Sea Kalkan and Azov Diamond (smaller subspecies);
- halibut flounder;
- halibut;
- black halibut.
River flounder, often called Baltic in Russia, is caught in the waters of the Baltic, in particular the Gulf of Finland. The real name of the species is river flounder. It comes from the fact that this species spawns in the sea, and prefers salt water, but is also capable of living in fresh water. Along with the tides, river flounder comes to the mouths of the northern rivers flowing into the Baltic and ends up in some lakes connected to the seas. Distributed from the coast of Norway to the Mediterranean. Up to 50 cm in length. Weight up to 3 kg.
Yellow-bellied flounder, on the contrary, avoids insufficiently salty waters. It is most widespread along the Pacific coast of Russia, although it is also found in the White Sea, and occasionally in the Black Sea. It has a characteristic bright yellow belly color. Large species: you can catch a trophy 60 cm long, but only in the Bering Sea.
The Black Sea flounder, also known as kalkan, inhabits the Black and Azov Seas and can enter the mouths of the Dnieper and Dniester. Endemic to the said seas, besides them, it is found to a limited extent only in adjacent areas of the Sea of Marmara. One of the largest species living in inland seas, it can reach a length of 1 meter and a weight of 30 kg. Left-sided view.
A brief description of these flounders would be incomplete without mentioning their ability to mimic. The skin of the upper surface of the fish is initially dark gray or brown, but contains pigments that allow it to change color, quite accurately copying the surface on which the fish lies, be it pebbles, sand or silt. Given the ability of fish to burrow into sand, this makes them practically invisible.
Note! ANDThe color change occurs quite slowly, over 2-3 days, and the fish must be able to see. Blind flounders are not capable of mimicking, but sighted ones can “imitate” even a chessboard.
Halibut flounder (similar to halibut) and various species of true halibut are found in the North Pacific and Atlantic Oceans. They are most common in the waters of the open seas - Barents, Bering, etc. Externally, they can be distinguished by their more elongated body.
Habitat
All these fish belong to benthic species. They live at depths of 30 to 200 m, buried in sand or even silt so that only the eyes and the upper gill slits are on the surface. It is what is used for breathing. The lower slot plays the role of a “jet engine” - by sharply releasing a stream of water through it, the flounder can unexpectedly take off.
Fish can also be found on pebble bottoms, mimicking pebbles.
Nutrition
All representatives of this family are predators, or rather benthophages. They feed mainly on bottom mollusks, crustaceans, and brittle stars. Some species, such as the river fish, "specialize" in hard-shelled animals that tend to be immobile or slow-moving. River flounder has very strong jaws.
A “more predatory” type of flounder is the kalkan. The basis of its diet is small fish, including mackerel, haddock, sprat, etc., as well as crabs - in a word, any bottom inhabitants.
Behavior in different seasons of the year
There were no significant differences in the behavior of adult flounder at different times of the year. The exception is the winter period. Most wintering species move further from the coast, to depths of 80-100 m (some up to 200). When it gets warmer, flounder returns to the coastal zone and shallows, sometimes, especially off the coast of Kamchatka, forming entire flounder “banks”.
Photo 2. Good catch of flounder.
Spawning
Different species of flounder reach sexual maturity in different years. For example:
- River - at 3-4 years.
- Kalkan - 6-11 years (females mature longer).
- Halibut - 10-14 years.
Representatives of all species go to spawn in late winter and spring, the last spawning month being May. Often the path to spawning grounds is very long, for ocean species it can be hundreds of kilometers. The eggs are spawned at depth, after which in most species the eggs rise to the middle water horizon.
Flounder is a very prolific fish. At one time it lays from 500 thousand to 10 million eggs. The most prolific species is the Kalkan, its record is 13 million. But, since the eggs are floating, most of them, as well as the vast majority of larvae and juveniles, are eaten by other fish. Of the total number of eggs in the spawning of one female, only 5-6 are able to go through the stages of larvae and fry in six months and survive until winter.
How to fish in different seasons
Flounder is a very picky fish and can be caught equally at any time of the year. The exception is winter sea fishing for flounder - it is complicated by the fact that the fish go far, to great depths. Therefore, winter fishing for sea flounder is practiced very rarely.
In winter, on rivers, especially in the delta, near the sea, this fish is caught with carp and feeder rods, as well as with special gear - a longitudinal line. The main difficulty is to find a place for flounder, because the tastes of this fish are unpredictable - it can stand on the shallows, or maybe in pits.
Photo 3. Sea bottom fishing rods.
Note! For sea fishing conditions, special sea fishing rods that are more resistant to salt water are recommended.
Any protein object can serve as bait - small fish, crabs, shellfish, worms, squid. There is evidence that flounder is even used for sausage.
There is also a special tackle for this fish - a longitudinal hook. It consists of a nylon cord, to one end of which a buoy is attached, to the other - a heavy sinker, so that the cord stands vertically in the water. Its length should be equal to the approximate depth at the fishing site. A separate piece of fishing line is tied to the weighted end, onto which leashes with hooks and bait are already tied - up to 4 pieces. The longitudinal line is installed at a given depth so that the fishing line with leads is stretched by the current, or the movement of the boat at low speed is used. After some time, the tackle needs to be checked for catch.
Flounder is an exotic fish, although it is quite common. It is very popular because of its appearance: the body is “flattened” horizontally, as well as because of its amazing taste and considerable usefulness of the meat. It is quite difficult to catch due to its ability to adapt to the color of the environment and burrow into the bottom.
Characteristics and classification
From birth, flounder fry are no different from the fry of other fish, but as they grow, they become more and more like adults.
In the first year of life they are symmetrical, but in the second year the fry lie on the bottom, as a result of which their structure changes very quickly and acquires the appearance characteristic of adults. The eye, which is located on the bottom side, moves upward, change the location of internal organs, the skin changes. The top of the fish’s body darkens and becomes covered with mucus, and the lower part remains white or light yellow, but becomes dense and rough to protect the fish from damage from sharp bottom surfaces.
The size of an adult varies from 30 cm to 1 meter, but on average the length of the most common commercial specimens is 40−50 cm. Usually this fish lives at a depth of 10−15 meters, but in some cases it can be found at a depth of up to 200 meters.
There are different types of flounder fish, as a result of which there are often disputes between flounder sea fish and river fish. The main types of flounder used for fishing purposes are:
![](https://i1.wp.com/sudak.guru/images/466967/kambala_opisanie_vneshnego.jpg)
Consequently, there are a couple of main species: river and sea flounder. They are not very different from each other in appearance, but their size and weight are different. As a rule, marine individuals are larger than river ones.
Nutritional features of flounder
All representatives of flounder-like animals are predators, so it’s easy to guess what flounder eats. Its diet consists of bottom-dwelling mollusks, crustaceans and brittle stars. Some species, for example river fish, eat slow and sedentary animals that have a hard shell. More predatory species, such as the white salmon, have a diet that includes small fish and crabs. Flounder especially favors capelin and shrimp.
The diet of flounder moths is slightly different. Their diet includes benthos, worms, amphipods, larvae, crustaceans and caviar.
Habitat and lifestyle
Due to the many varieties, the distribution area of this fish is very wide.. She lives:
![](https://i0.wp.com/sudak.guru/images/489102/lovit_rybu_kambalu.jpg)
Flounder lives on the bottom in absolute solitude, successfully merging with the color of its landscape. Basically, the fish lies on the surface of the bottom soil or buried in its sediments up to the eye level. This allows the flounder to remain undetected by larger predators, and also to obtain food by stalking prey from ambush.
Despite the external slowness of the fish, it is an excellent swimmer. If required, it can take off instantly and reach high speed over short distances. This is achieved due to the fact that the flounder “shoots” water with strong pressure into the bottom through the gills located closer to the bottom. And while the silt or sand that rose from the bottom at this time dissipates, the fish manages to grab its prey, and also hide from the predator that discovered it.
From February to May she has a breeding season. Active spawning occurs in various individuals in different times depending on where they live. During the spawning season they gather in flocks. It happens that different species of flounder gather in one flock, resulting in crossing of species.
The ability to spawn in this fish appears at different ages depending on the species: in the river fish at the third or fourth year of life, in the kalkan at six to eleven years, in the halibut at ten to fourteen years. During this time, she can spawn hundreds, thousands and millions of eggs, depending on their variety and size. However, most of the eggs are eaten by other fish, and in the spawning of one female, only a small number of fry are able to survive and survive until winter. Incubation The egg period is eleven days, after which fry are born from them.
The lifespan of flounders varies depending on the sex: males live from twenty to twenty-five years, and females are slightly longer - up to thirty years.
So, the flounder has gone through a long evolutionary path in its development, having learned to hide perfectly on the bottom, practically merging with it, to live and reproduce in completely different conditions. It is unlike any other fish species, having a flat appearance as its unique feature.
In our article we want to talk about flounder. What it is? Flounder is a flat sea fish that has long been popular due to its tasty and very healthy white meat.
Flounder and its subspecies
When talking about this interesting fish, it should be noted that it has become popular among housewives due to its taste. However, not everyone knows for sure: flounder is a sea fish or very often disputes arise on this subject.
So, eleven families, including about 570 species, are united into a single group under one name. Of the entire set of these fish, only three are classified as freshwater, and all the rest, accordingly, are marine.
Appearance of fish
Flounder (sea flounder) swim and look quite normal, but as they age, their eyes and mouth move to one half of the body, which, in turn, becomes very flat and asymmetrical. Naturally, the skeleton and internal organs change. Adults lie on the bottom with the lower part of their body and only occasionally rise, beginning to move in wave-like movements.
Sea flounder is a predatory fish that feeds on bottom living organisms.
Habitat
Flounder is one of those fish that live on the seabed. Sometimes it can be found near river mouths. As a rule, it swims at depths of ten to two hundred meters, and in the Black and Mediterranean Sea its habitat expands to four hundred meters. In addition, this fish is also found off the coast of Scandinavia, Europe, Norway and North Africa.
Different species choose different depths to live, each of them adapts to certain conditions, preferring a certain soil.
Flounder (sea fish) buries itself in the sand in such an amazing way that it is completely invisible, and only its eyes remain on the surface. And they do it very quickly. Using wave-like movements of their bodies, they lift sand, then sink to the bottom, and silt settles on them, covering them from above.
Fish habits
It doesn’t matter whether the flounder is freshwater or saltwater, all representatives of this family are very poor swimmers. Sensing danger, the fish turn over on their edge and quickly swim away in this position. As soon as the danger has passed, they sink back to the ground and burrow.
Depending on where the flounder lives, it is capable of changing its color at lightning speed, acquiring the desired shade. The color of the fish depends primarily on the color of the seabed and its pattern. When changing, flounder achieves such colors as to be practically invisible. This kind of adaptability is called mimicry. But not all representatives of this genus have this property, but only those that see. Having lost its sight, the fish will no longer be able to change the color of its body.
Flounder is a sea fish whose size ranges from a few grams to three hundred kilograms. Its weight and size depend primarily on the type. Some individuals reach four meters in length.
Halibut
Many of us have heard of halibut, but everyone knows that it is flounder. What kind of fish - river or sea - is certainly not known to many. Meanwhile, halibuts are the largest flounder that live in the Pacific and Atlantic oceans. A fish weighing 363 kilograms was recorded, and this is the largest value known to science. An interesting fact is that this species of flounder can live up to fifty years of age. In addition, flounder is a valuable marine commercial fish.
It spawns at great depths - from three hundred to seven hundred meters. To do this, fish choose deep holes, which are usually located along the coast. Halibut mainly spawns off the coast of Norway, as well as off the Faroe Islands, off the coast of Iceland, Scotland, and Greenland.
Commercial halibut fishing
Halibut is highly valued for its high taste. However, its catching is strictly controlled. And this situation is connected, first of all, with the peculiarities of the life of fish. The fact is that flounders do not form schools; they swim alone. In addition, halibuts grow very slowly, and therefore large specimens are extremely rarely caught by fishermen.
But a way out of this situation was found, because it is possible to breed fish in artificial conditions. For this purpose, young animals are raised in pools. When it reaches a weight of one hundred grams, it is moved to sea backwaters where the halibut grows and develops. Fish that reaches a weight of two to five kilograms is considered marketable.
Black Sea Kalkan
The flounder that lives in the region is called the kalkan and is a very valuable and tasty fish. Moreover, it has commercial significance. For example, in Turkey, a kilogram of Kalkan costs at least fifteen dollars. In the middle of the last century, two to three tons of this fish were caught annually off the coast of Crimea. However, soon its reserves decreased significantly, which became the reason for the ban on its catching. Currently, there is no such ban, which leads to a decrease in its number. The fish are caught using multi-kilometer nets that block the migration routes of the Kalkan for spawning. This is the traditional way of catching it. This phenomenon is considered illegal, and recently such catching has become quite large-scale, which can lead to a critical decrease in the number of Kalkan in the Black Sea.
Kalkan lives not only in the Black and Azov Seas, but also enters the Mediterranean, as well as at the mouth of the Dnieper and Dniester. This species of flounder prefers sandy and silty soils, and does not fall below one hundred meters. Kalkan, which lives in the Sea of Azov, is called Azov. In principle, it is no different, only slightly smaller in size than the Black Sea.
Since this is a predatory fish, its diet includes mollusks, crustaceans, and small fish. Juveniles generally prefer crustaceans, while adults tend to eat fish and crabs.
Moses flounder
The Red Sea is home to ten varieties of flounder. The most famous among them is the Moses flounder. It is relatively small in size, about twenty-five centimeters, and lives at a depth of no more than fifteen meters. It feeds on invertebrate animals, moves very little, and lies buried in the sand almost all the time.
Freshwater flounder
River flounder lives in freshwater bodies of water. It is capable of traveling hundreds of kilometers, entering the seas. This species also belongs to the same family as halibut, but has a much more modest size and weight (five hundred grams).
There are quite a lot of river flounder in the Baltic Sea, and therefore it is classified as a widespread marine species. It has commercial significance. River flounder lives at a depth of sixteen to eighteen meters, preferring sandy soil.
This species is considered an ordinary resident of the Gulf of Finland, and you won’t surprise anyone there with it. At the same time, an interesting fact is that the fish prefers the southern part of the bay to the northern one. This phenomenon can be explained quite simply. The southern part is influenced to a greater extent by the Baltic Sea; here the water is saltier.
During the period it lays many eggs (up to two million). This process occurs in the spring. And in the Gulf of Finland it lasts from May to June. The female lays eggs directly on the sand or bottom, and already in the water the eggs begin to develop.
Turbot
Turbot is a type of flounder. Outwardly, it is very similar to a large rhombus and is larger in size than the river type. Some individuals reach one meter in length, and the bulk, as a rule, does not grow more than eighty centimeters. The peculiarity of turbot is that this fish has a high body. She is a predator and has a big mouth.
Its diet includes gerbil, cod, and, oddly enough, river flounder, mollusks are also used, and turbot hunts in the same way as other flounders, it moves slowly, looking for a potential victim, then waits for it in the shelter, changing color. It lives at considerable depths (up to one hundred meters).
Properties of flounder meat
Flounder is of great gastronomic interest in terms of its delicious meat. It has long been loved by many, the reason for this is not only its taste, but also its beneficial properties. All varieties of flounder contain up to twenty percent protein and a set of amino acids, and only three percent fat. In addition, fish contains a lot of vitamins: A, PP, E, B and others. Flounder is a source of Omega-3 fatty acids.
It is believed that with regular consumption of this type of fish, efficiency and immunity increase, cholesterol levels decrease, the condition of teeth, hair, skin improves, and the functioning of the thyroid gland and heart improves. Thanks to these properties, flounder is recommended for the dietary nutrition of children and weakened people.
Commercial fishing
Flounder is one that is caught using bottom trawls. This fishery is developed off the Norwegian coast, in the Barents Sea and in the Far East. In the Azov and Black Seas, fishing is more likely to be poaching. Halibut (a type of flounder) is very common in the Pacific and Atlantic oceans, yellow stripe fish is found in the Atlantic, and Atlantic flounder is found in the Atlantic, off the coast of Europe. In addition, river species can be found in the same regions. The following species predominate in the Azov-Black Sea region: sole, kalkan, glossan, smooth diamond.
Fish is sold fresh frozen or chilled. It can be of different sizes depending on age. Specimens aged from three to six years are considered optimal for industrial fishing.