Fauna of the Baltic Sea. History of the formation of flora and fauna. What sharks live in the waters of Russia

The geological past and the current regime of the Baltic Sea make it possible to understand the composition of its population.

The freshwater Baltic Ice Lake-Sea was inhabited by freshwater fauna, and it is difficult to decide whether any components of this original fauna remained in the Baltic Sea. But this issue is not of significant importance, since in all subsequent time the freshwater fauna had the opportunity to penetrate into the Baltic Sea, if this was allowed by the physiological and biological characteristics of certain freshwater forms (their eurytopicity). In the history of the Baltic Sea, the freshwater fauna almost completely captured the reservoir several times, especially during the phases of the Ice Lake and the Ancylus Sea. As they penetrate deep into the sea, into its northern and eastern parts, the admixture of freshwater forms becomes more and more noticeable, and in the most desalinated parts of the sea, freshwater organisms make up a significant part of the population. Freshwater forms penetrate into the Baltic Sea up to a salinity of 4-5‰, and some forms are also found at a salinity of 7‰. Of the freshwater molluscs, the most common here are various pond snails (.Limnaea), neritina, bitinia, palyudina and coils (.Planorbis). A very common crustacean is the water donkey (Asellus aquaticus), in large numbers the larvae of bloodworms (Chironomidae), etc.

The same is true for plankton. Freshwater blue-green algae, and especially Aphanizomenon (Aphanizomenon flos aquoe) and a very large number of euryhaline freshwater rotifers, various species of the genera Brachyonus, Anurea, Triarthra, Polyarthra, Asplanchna, etc., are widely distributed among planktonic algae in the Baltic Sea. Some freshwater forms, especially diatoms and rotifers, which we have already written about above, give the strongest development not in fresh, but in brackish water at a salinity of 3-5‰. Here they mix with brackish and marine forms.

A significant trace in the fossil and modern fauna of the Baltic Sea was left by the salty and cold Yoldian Sea. At that time, when the entire northern part of the Atlantic Ocean was also subjected to strong cooling, cold-water fauna penetrated into the Baltic Sea, the most resistant to salinity, part of which still exists in it today.

Many forms from this group have a relict or semi-relict character in the Baltic Sea, as they are cut off from the main area, which was moved northward by the onset of warming. The harp seal (Fig. 228) is extinct in the Baltic Sea, others have survived.

Figure 228.

Of these, as an example, one can name the mollusk astarte (Astarte borealis), the halicryptus worm (Halicryptus spinulosus), the crustacean pontoporeia (Pontoporeia femorata) (Fig. 229) and many others.

Figure 229.

They are completely absent from the western coasts of the Scandinavian Peninsula, but their main distribution is confined to the Arctic Ocean. Among these forms there are also typically marine forms, such as the mollusks astarte, or maqoma (Masota calcarea), or the halicryptus worm; there are also those that are found mainly near the coasts and endure strong desalination, such as, for example, the mysis crustacean (Mysis oculata). In the Baltic Sea, they are found only in the westernmost part or in its south, like astarte or halycryptus (Fig. 230).

Figure 230.

In general, the fauna of the Baltic Sea is dominated by arctic forms, due to its severe winter regime. Some groups of animals are represented in the Baltic Sea by 70% by arctic forms, and in the North Sea by only 20%. An amazing similarity in the composition of the fauna is observed between some parts of the Baltic Sea, in particular its deep zone and the eastern coast of Greenland - one of the coldest regions of the Arctic.

The situation is somewhat different with another group of Arctic relics in the Baltic Sea, with its brackish-water relics, found only in the most desalinated parts of the Arctic Ocean, in the mouths of the rivers flowing into it, in many fresh lakes associated with these rivers, up to the Caspian Sea. . We have already spoken above about these forms of fish and crustaceans. These are the same crustaceans - mysis, pontoporeia, gammaracanthus, pallasea, limnokalyanus, mesidothea, fish - four-horned goby, smelt, whitefish and many others. This characteristic relict brackish water complex arose back in pre-Joldian times, and the Baltic Sea is its secondary area. It is difficult to assume that these forms, which cannot endure waters of full salinity, could penetrate into the Baltic Sea, like the previous ones, in the cold postglacial period from the west, from the North Sea. It is more likely that they entered the Baltic Sea basin during the Ice Lake period and not from the west, but from the northeast, from the Arctic. Perhaps, they partially penetrated from the northeast already in the Yoldian time through the strait connecting the Baltic with the White Sea.

Many brackish-water relics in the Baltic Sea are confined to the coldest and desalinated parts of it (Fig. 231), a very striking example of which are the crustaceans Limnocalanus (Limnocalanus grimaldii) and Pontoporeia (Pontoporeia affinis).

Figure 231.

A peculiar place in the fauna of the Baltic Sea is occupied by brackish-water invaders from the far south - from the Caspian Sea, who penetrated there during quite a recent time, one might say the last century. These are the hydroid polyp Cordylophora caspia, the bivalve mollusc Dreissena polymorpha, and the amphipod Corophium curvispinum. All three forms can be easily distributed with riverboats; the first two are attached to underwater objects, and the third lives in thin tubes, which also help it stay among the fouling on the bottoms of ships. Obviously, these "travelers" penetrated from the Caspian into the Baltic Sea by the Mariinsky system.

During the Littorina period, more heat-loving (boreal) flora and fauna from the Atlantic Ocean began to penetrate into the Baltic Sea, and a fourth component was added to the three considered above, which is currently perhaps the most abundantly represented in the population of the Baltic Sea. It is quite obvious that of the rich Atlantic fauna, only the most euryhaline and shallow-water forms were able to penetrate into the Baltic. However, the subsequent decrease in the salinity of the Baltic Sea by 5-6‰ led to the extinction of many of them, including several species of seals, in particular the harp seal, coastal marine mollusks Littorina (Littorina littorea and L. rudis), etc.

At the same time, the Baltic Sea was inhabited by forms, now the most widespread in it, and among them the littoral forms of the North Atlantic have a huge predominance - from bivalve mollusks makom (Masota baltica), mussel (Mytilus edulis), edible cockle (Cardium edule) and sand shell (Mua arenaria), from sea sandworms (Arenicola marina), priapulus (Priapulus саudatus) and halicryptus (Halicryptus spinulosus), from crustaceans amphipods (Gammarus locusta and G. duebeni), Iera isopod (laera albifrons), barnacle - sea acorn ( Balanus improuisus) and butterfish (Рholts gunellus) and eelpout (Zoarces viviparus). All these littoral animals are already known to us from the dry strip of the Barents and White Seas. But the Baltic Sea is without water, and in it littoral animals have gone (Fig. 232) under the sea surface and often to depths of several tens of meters, since as a result of a long existence on the dry strip of the sea, they have developed the ability to easily endure sharp fluctuations in environmental factors, in including salinity.

Figure 232.

The introduction of individual Atlantic forms into the Baltic Sea is also taking place in our time, and this process cannot yet be considered complete. A number of forms of polychaetes, crustaceans and molluscs have entered the Baltic Sea in the most recent decades.

We have already mentioned a remarkable traveler - the Chinese crab (Eriocheir sinensis), brought by ships from the China Sea in 1912 to the mouth of the Elbe. Over the past quarter of a century, the crab has spread not only along the North Sea and the rivers of its basin, but also along the rivers of the Baltic Sea basin (Fig. 233).

The Baltic Sea belongs to the Atlantic Ocean basin, is located in Northern Europe and has a surface area of ​​415 km2. Many rivers flow into it, so it has an average salinity, this is one of the largest seas in the world with such a feature. There are no big storms in the Baltic, the maximum wave height rarely exceeds 4 meters, so it is considered calm in comparison with other seas. The water temperature is quite cold, no more than 17-19 degrees Celsius, but this still does not stop the locals from swimming in the summer.

9 neighbors of the Baltic

The Baltic Sea washes the shores of several countries: Russia, Estonia, Latvia, Lithuania, Poland, Germany, Denmark, Sweden and Finland. It has four bays: Finnish, Bothnian, Riga and Curonian. The latter is separated from the sea by a strip of land - the Curonian Spit, which is a national natural park and is protected by the state. Interestingly, this nature reserve is divided between two states: Russia and Lithuania.

inhabitants

The Baltic Sea is rich in seafood. Their extraction is carried out in the Kaliningrad region and European countries. The water here is not as salty as in other seas. Therefore, some scientists conditionally divide the inhabitants of the Baltic Sea into freshwater and marine. The bays are mostly inhabited by freshwater fish. The sea is located at a distance from the coast. In the Baltic there is:

• Salaka. This small fish rarely grows more than 25 cm. It is the main commercial fish of the Baltic Sea, about half of the total catch falls on it. Salaka is smoked, fried and canned.

• Baltic sprat. A very common fish in Europe, one of the well-known names is "European sprat". The sprat is smaller than the herring, the adult grows no more than 15 cm. In cooking, this fish is universal, like the herring, but most often it is used to make canned food.
• Cod. This sea meat is rich in protein and minerals, it is a good source of B vitamins. Cod meat is also high in niacin, which is useful for liver diseases. It grows up to 1 meter long, the largest individuals can reach a size of up to 2 meters, but this happens very rarely. Cod is loved in many countries of the world, there are a lot of recipes for cooking dishes from it, a special delicacy is cod liver canned in oil. Cod is one of the most delicious marine life in the Baltic Sea.

• Flounder. This is a marine bottom fish of a bizarre flat shape. Its most memorable feature is a flat body and eyes located on one side, so it is impossible to confuse a flounder with another fish. The scales of this fish are rough like sandpaper. On average, a flounder lives for 5 years and grows up to 40 cm in length. It has white, tasty, tender meat, although when cooked, it emits a specific smell that not everyone may like. To get rid of discomfort during cooking, you need to remove the skin from the fish. Flounder meat contains proteins and useful amino acids that are well absorbed by the body. Flounder is considered a dietary fish.

• Acne. This amazing inhabitant of the Baltic Sea is included in the list for a reason. It is found in all reservoirs of the Kaliningrad region. You can catch an eel not only in sea water, but also in freshwater rivers. Outwardly, the eel looks like a snake, has a long body and swims, wriggling like snakes. In length, an adult grows up to 1.5 m, and weighs about 2 kg. Eel meat contains proteins, fats and carbohydrates, and is also a source of omega-3s. The most common type of eel preparation is smoking.

• Perch. Very bony and tenacious fish, can live up to 15 years. Meat is stored for a long time, it contains many vitamins and nutrients.

valuable fish

• Salmon. This is a fish from the salmon family, in the Baltic slightly salted waters there is an Atlantic salmon, which is sometimes called "Baltic". This type of "noble" sea fish is popularly known as "salmon", it is quite large, an adult male can reach a length of more than 1.5 m. The taste of salmon meat is tender and oily, the color varies from light pink to red. The salmon fillet contains almost no bones, so it is popular among those who do not like fish because of the fear of swallowing a small bone. Many dishes are prepared from this fish, including the well-known red salmon caviar, which appears on our tables on special occasions.
• Smelt. Surprisingly, the well-known smelt belongs to the salmon family. It is generally accepted that this fish is not valuable, despite the fact that it is caught in the Baltic Sea in large numbers. Smelt meat is rich in iron and fluorine, doctors recommend including it in your diet for the elderly.

• Vendace. This small fish is also from the salmon family, its peculiarity is that it lives exclusively in the waters of the Baltic Sea. Vendace from noble fish, therefore, is considered a valuable raw material. She is loved in Europe and Scandinavian countries. In many regions of Russia, vendace is under protection and it is impossible to catch it just like that.
• Whitefish. Fish of the salmon family is considered a valuable commercial fish and has more than 40 species. Despite the fact that whitefish belongs to the salmon family, its meat is white and very fatty. Because of this feature, whitefish meat is not stored for a long time, so it is consumed or salted immediately after being caught.

Mollusks, crustaceans and jellyfish

In addition to the listed fish, molluscs, squids, small crustaceans and bottom fish live in the Baltic waters. Very rare is the mitten crab, which appeared here relatively recently. Jellyfish are also found in the Baltic Sea, the largest - cyanide - lives near the waters of Denmark. In the rest of the space lives a harmless Aurelia, an inhabitant of the Baltic Sea, whose photo is not as intimidating as the one presented above.

mammals

Of the mammals in the Baltic Sea, only three species of seals live:

• Tuvyak (grey seal).
• Nerpa (common seal).
• Harbour porpoise.

Dangerous inhabitants

There are no dangerous inhabitants in the Baltic Sea, of the sharks you can only find a katran - a small shark with spikes on its fins, it is not dangerous to humans. She does not swim to the Russian shores, she lives in the Danish straits, where the Baltic Sea connects with the North.

Window to Europe

The Baltic Sea is an inland sea of ​​the Atlantic Ocean basin and is located in a shallow depression between the Scandinavian Peninsula and the European continent. Through the system of the Danish Straits, through the North Sea, the Baltic Sea is connected to the ocean.

The surface area is 386 thousand sq. km, the average depth is 71 m, the maximum depth is 459 m (Landsortsupet basin south of Stockholm).

The ancient Slavs called this sea the Varangian.

As a result of studying the bottom topography and the nature of the soils, scientists came to the conclusion that in the preglacial period, there was land on the site of the Baltic Sea. Then, during the ice age, the depression in which the sea is now located was filled with ice, the process of melting of which led to the formation of a lake with fresh water.

About 14 thousand years ago, this lake joined the ocean as a result of the sinking of land areas - the lake turned into a sea. Then, after the next rise of land in the region of Central Sweden, the connection between the sea and the ocean broke, and it again turned into a closed lake-type reservoir.

Approximately 7 thousand years ago, another land subsidence occurred in the area of ​​​​the modern Danish Straits and the connection of the lake with the Atlantic resumed.

Subsequent fluctuations in land level led to the formation of the modern Baltic Sea.

The rise of land in the area continues at the present time. Thus, in the area of ​​the Gulf of Bothnia, the bottom rise is approximately 1 m per 100 years.

Climate in the area of ​​​​marine temperate, characterized by small seasonal temperature fluctuations, frequent precipitation in the form of rain, fog and snow.

Temperature surface water reaches +20 degrees C in summer. As you move north, the water is cooler and in the Gulf of Bothnia does not warm up above +9 - +10 degrees C. In winter, the water cools down to freezing temperature and the northern bays of the sea are covered with ice. The central and southern regions usually remain ice-free, but in exceptionally cold winters the sea can become completely ice-covered.

Water in the sea it is highly desalinated, especially in areas remote from the Danish Straits. The reason is the numerous rivers and streams (almost 250) flowing into the sea.

Among the major rivers Neva, Narva, Vistula, Kemijoki, Zapadnaya Dvina, Neman, Odra can be noted.

currents in the sea they form a cyclonic circulation, often their direction and speed are corrected by the winds.

tides in the sea are very low - 5-10 cm, however, wind surges of water, especially in narrow bays, can exceed 3-4 meters.

Coastline The Baltic Sea is heavily indented. There are many large and small bays, bays, capes, spits. The northern shores are rocky, as you move south, the rocks and stones are replaced by sand-pebble mixtures and sand. Here the shores are low and flat.

Islands of mainland origin, especially many small rocky islets in the northern part of the sea. Large islands: Gotland, Bornholm, Sarema.

Bottom relief the sea is complex. There are many ups and downs here, which appeared as a result of the activity of glaciers, river beds, land fluctuations. However, the elevation changes are small - the sea is shallow.

Animal world The Baltic Sea is relatively poor in represented species. A feature of the marine fauna is the distribution of freshwater and marine animal species in different areas. In the northern, fresher regions, especially near the mouths of the rivers, live mainly freshwater animals and species that easily tolerate desalination. Closer to the Danish Straits, the waters of the sea are much saltier, so you can meet many typical marine life here. The general species composition of the sea is scarce, but rather rich in quantitative terms.

The poverty of the fauna of the sea is also explained by its youth, because in the form that it has now, its age is estimated at only five millennia. According to scientists, another 5,000 years will pass, and the Baltic Sea will again lose contact with the ocean and turn into a large fresh lake. Many forms of marine life in such a short time simply did not have time to adapt to local conditions of existence.

Nevertheless, the quantitative composition of animals living in the Baltic Sea is quite large.

Bottom animal species are represented mainly by worms, gastropods and bivalve mollusks, small crustaceans and bottom fish - flounder, gobies. In some places you can meet the mitten crab - an alien from the North Sea and accustomed here. Near the Danish Straits, there is even a giant among jellyfish - cyanide. And another type of jellyfish - eared aurelia in the Baltic Sea is found almost everywhere. Small schooling fish - three-spined stickleback, Baltic sprat.

In the desalinated areas of the sea, there are many river fish: roach, perch, pike, bream, ide, pike perch, migratory whitefish, burbot, etc.

In the Baltic Sea hunt such valuable fish as herring (about half of the total fish catch), sprat (sprat), salmon, eel, cod, flounder.

Marine mammals only three species of seals are represented in the Baltic Sea: the gray seal (tuvyak), the common seal (seal), and the harbor porpoise, which belongs to toothed cetaceans.

sharks in the Baltic Sea are represented only by the ubiquitous katrans - a small spiny shark, which is dangerous to humans only for its spines on the dorsal fins. But these fish are not settled in all areas of the sea - too desalinated and shallow areas are not suitable for them to live.

However, in the area of ​​​​the Danish Straits, connecting the Baltic with the North Sea, other predators are sometimes found - herring sharks. No such guests have been registered off the Russian shores of the Baltic Sea.

In conclusion, I would like to note that at present the Baltic Sea is intensively polluted by various chemical and biochemical effluents, as well as by trace elements contained in precipitation. This leads to the mass death of microflora and microfauna, which settle to the bottom in large quantities and are processed by bacteria into hydrogen sulfide. And hydrogen sulfide has a detrimental effect on all living organisms in the bottom layer of water. If urgent measures are not taken, the number of aquatic animals in the sea will decrease significantly.

The Barents Sea is rich in various fish species, plant and animal plankton and benthos. Seaweeds are common off the south coast.

114 species of various fish have chosen to live in the Barents Sea, among which 20 species are of commercial importance: herring, cod, haddock, sea bass, blue whiting, catfish, flounder, halibut (Atlantic, blue-crusted) and others. European smelt, various gobies, chanterelles, liparis and other small fish are numerous.

Among the larger inhabitants of the sea, marine mammals should be noted: harp seals (common, bearded seal, gray, ringed seal, coot or harp seal, hooded whale) and cetaceans: minke whales (fin whale, sei whale, minke whale, blue whale, humpback whale), dolphin (beluga whales, narwhals), right whales (bowhead whale). Occasionally killer whales enter the waters of the Barents Sea. All these animals feel great in cold water due to the large amount of fat in the subcutaneous layer, muscles and internal organs.

Pinnipeds are the subject of fishing because of the skin, fat, meat.

Among the sharks that are found in the Barents Sea, it should be noted katran (marigold), herring, polar and giant sharks. The frilled shark is very rare. Even less often is the capture in the southwestern part of the sea (Norwegian waters) of some species of gray and cats sharks. Description of all these toothy fish you can find on the pages of the site. Some sources mention extremely rare visits to the Barents Sea (in especially warm years) by great white sharks. How true this information is is not known. If you believe the words of professional divers who have been working in the waters of the Barents Sea for decades, then it is more difficult to meet a dangerous shark here than a wolf in the center of Moscow. And it’s hard to find those who want to swim in its cold waters. Therefore, the Barents Sea is considered to be safe for sharks.

Tourist centers

The Barents Sea is very popular with ice divers as it is home to a wide variety of species: sea urchins and groupers, giant sea anemones and kelp beds. In the Barents Sea, you can even find king crab, which was brought here in the middle of the last century by Soviet scientists as an experiment.

The experiment was a success: the crab successfully acclimatized and began to destroy the local underwater inhabitants, causing a lot of unrest to environmental organizations. The range of claws of some crabs reaches two meters, which can quite frighten an inexperienced diver.

However, such divers have nothing to do in the Barents Sea, as diving in icy water requires decent training. The recommended level is Advanced OWD PADI, and the Dry Suite PADI certificate is also required. It is worth paying attention to the fact that the weather on the coast of the Barents Sea is unstable: the bright sun is instantly replaced by rain, the fog is replaced by a cold wind. But underwater weather is more stable: 5-7°C in winter, 10-14°C in summer.

Baltic Sea

Baltic Sea- the inland marginal sea of ​​Eurasia, deeply protruding into the mainland. The Baltic Sea is located in northern Europe, belongs to the Atlantic Ocean basin.

Area: 415 thousand square meters km. Depth: average - 52 m, maximum - 459 m.

The Baltic Sea is elongated approximately from the southwest to the northeast, with its northernmost point located near the Arctic Circle (65 ° 40 "N. Lat.), and the southernmost point - near Wismar (53 ° 457 N. Lat.), so that in latitude it occupies about 12 ° In longitude it stretches for about 21 ° - from the westernmost point near Flensburg (9 ° 1 (E) to St. Petersburg (30 ° 15 "E). Thus, individual areas of the Baltic Sea lie in different geological and climatic zones, which is of great importance for the oceanological conditions in these areas.

When looking at the outlines of the sea, its strong dissection is striking. Its isolated parts, such as Katgegat and the straits of the Small and Big Belt, form a natural transitional area between the Baltic and the North Sea, while in the north and east the bays of Bothnia, Finnish and Riga adjoin the main part of the sea.

Countries bordering the Baltic Sea: Russia, Estonia, Latvia, Lithuania, Poland, Germany, Denmark, Sweden, Finland.

Coastline

The boundary between land and sea, the coast line, is probably the most remarkable and important natural boundary on our planet. Here the hydrosphere, lithosphere and atmosphere come into contact and interact with each other. On the coast line, the two eye boundary surfaces of the ocean - the upper (water - air) and the lower (water - bottom) - pass into each other. These general propositions also fully apply to the Baltic Sea, where along the coastline stretching for many thousands of kilometers there are the most diverse forms of coast and where the transforming activity of the sea can be constantly observed.

What beaches form

Steep banks are usually composed of moraine material, mainly marl pebbles and boulders. Under the influence of precipitation, frost, melt water and washing away of the foot, the slope of the coast becomes unstable, and when it collapses, a steep slope is formed. The sea carries away the collapsed loose material from the foot of the cliff (cliff) and forms a new coastal slope, which collapses again after some time, etc. Thus, the retreat of the coast observed today also occurs. In these parts of the coast, flat inclined surf terraces, the so-called shorrs, are formed, usually covered with sand and pebbles. Schorras, like the coast itself, are extremely diverse in character. Further towards the sea, characteristic sandbanks (banks and reefs) are formed. Near the shore, so-called hakenes arise, which, with further development, can turn into spits. There are also regularly found coastal bars and longitudinal strips covered with water on the beach, which expands in such places. In the same areas, extensive dunes often form, which can reach more than 10 m in height.

Somehow it turned out that of the sharks in the Baltic Sea, only two species are represented: the ubiquitous katrans and herring sharks.

And if the katran for people is only of decorative interest, neither as a hunter, nor as a victim of katran is not interesting to a person, then the herring shark can engage in cannibalism.

What can be said about the katran, if you do not focus on the fact that it is just a beautiful small predatory fish? He doesn't attack people, he just doesn't see the point in it. People do not use katran for culinary purposes, for the reason that its meat is too saturated with urea, and, therefore, the game is not worth the candle. Let yourself swim.

And the herring shark is a relative of the mako shark, which, according to the latest scientific data, is a greater relative of the megalodon than the great white shark. And this means that the herring shark is potentially dangerous to humans. She is fast and aggressive, in any case, you should not mess with her. Although they don't often swim into the Baltic Sea from the Atlantic Basin, if you spot these silvery silhouettes in the water from your boat, it's best to stay away from them.

True, it can be noted with regret that the Atlantic herring shark is now not such a frequent visitor to northern waters, but this is due to the fact that it has become an endangered species. This is how the glory of the world passes, as the ancients said.

When going fishing, think about what kind of equipment for a float fishing rod for crucian carp is better. If you visit our site, you will be pleasantly surprised by the large selection.

Baltic jaws

Shark Days celebrated in Europe. By the date, the Baltic media burst into stories, the meaning of which is that the year when our Baltic Sea will literally be teeming with sharks is not far off. The reason is global warming. Some unnamed Lithuanian scientists allegedly said that in the near future, frightening fins could be observed in our area.

There are over 4,000 shark species in the world. Many of them are able to live in water, the temperature of which does not reach even 5 degrees above zero. The Baltic Sea warms up well in summer to 1520 degrees and more. According to the Lithuanians, the fact that our sea will soon become suitable for the bloodthirsty inhabitants of the oceans is also evidenced by scientific facts. So, on the beach of Klaipeda in the 1990s, a dead fish sword was discovered.

Are we in danger of a shark invasion? What do not anonymous, but quite real researchers say about this? As it turns out, fear has big eyes. The Riga biologist Andris Kalnins only laughed when he heard my question about a television plot dedicated to the toothy smaller brothers.

According to him, in the near foreseeable future, the inhabitants of the Baltic States, who decided to swim, should hardly be afraid for their lives. The main obstacle for sharks is not the temperature at all, but the degree of salinity of the water. The Baltic Sea contains 6 times less salt than the World Ocean. And for large predators, salt is extremely necessary in salt water for a heavy body to hold on easier. After all, sharks do not even have an air bladder. They always have to be in motion, otherwise they simply fall to the bottom. In addition, the water in the Baltic is too dirty, because the channel of exchange with the World Ocean is too narrow Danish straits.

If you take a little liquid from our sea and pour it into your home pool, then the container will immediately begin to overgrow with all sorts of filth. But fish passes water through membranes. In addition, there are areas in the Baltic Sea where the level of oxygen is extremely low, which means that all living things die. Cod is in big trouble right now. Floating eggs are often carried into dead zones, of which, alas, there are more and more every year.

In a word, in the near future we are more likely to face not an invasion of sharks, but the complete disappearance of the rest of the inhabitants of the Baltic. And the appearance of all sorts of muck with a purple tint along the coast is another confirmation of this.

The seas washing the Russian coast have traditionally been considered completely safe from the point of view of the possibility of being attacked by a shark.

Western marine reservoirs and the waters of the Arctic Ocean are not favorite habitats for dangerous predators. The Black, Baltic and Azov seas sheltered an ordinary katran in their waters, threatening a careless fisherman only with prickly spikes on the dorsal fin.

In addition to the katran, the Black Sea is visited by an even less dangerous cat shark. which in warm weather sails from the Mediterranean Sea. This is a small species of bottom sharks, whose individuals only in exceptional cases reach a meter in length and weigh a little more than a kilogram.

In fairness, it should be noted the appearance in the press of dubious information about the capture of a goblin shark in the waters of the Black Sea. and also at the mouth of the Neva, the herring shark. But this information is not documented and is highly doubtful. Therefore, we can safely say that in the seas of the Atlantic basin, adjacent to the coast of Russia, there are no other sharks, except for the katran and the feline. Both of these species are not dangerous to humans.

The seas of the Arctic also did not react very kindly to the attempts to penetrate their waters of the toothy robbers. Only the polar shark feels like a full-fledged mistress here, and the ubiquitous katrans and herring sharks found in the White and Barents Seas. The waters of the Barents Sea are often visited by a giant shark - a plankton-eating representative of cartilaginous fish.

Sharks are somewhat richer in the waters of the Far Eastern seas of Russia, especially the Sea of ​​Japan. The presence of more than a dozen different types of sharks was noted here, among which there are predators dangerous to humans.

It is quite possible that in the depths inaccessible to swimmers and divers, there are other rare species of sharks - the frilled shark. goblin. comb-toothed and others. In the depths of the ocean, the water temperature is relatively stable and these predators may well violate our maritime state borders.

The greatest danger to humans in the Sea of ​​Japan is the great white shark and mako, included in the list of the most dangerous species. Potentially dangerous giant hammerhead. salmon, sharp-toothed mustelid and gray short-finned shark. Sometimes the fox shark behaves quite boldly in the presence of divers, but it is not found off the coast.

The events of the summer of 2011, when sharks bit our compatriots in Primorye, removed the shark-safe status from the Russian seas, and made us take a closer look at the issue of ensuring the safety of Russians' favorite vacation spots.

Sources: www.akyla.info, scubascuta.com, akully.ru, morefishes.ru, newsland.com

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Pitaya is a tree-like cactus growing in a bush. Fruits ripen at the ends of the stems. It begins to bloom without fail on the first day of the month and ...