Some people, especially after sensational reports of shark attacks in Egyptian resorts, asked themselves: are they safe for bathers and divers in the Black Sea? Are there any sharks in the Black Sea, and is it possible to meet them on the coasts of the Caucasus and Crimea?
In order to comprehensively answer this question and calm all sorts of worries, it is simply necessary to take an excursion, albeit a brief one, into the history of the occurrence of the water area, which is now commonly called the Black Sea. 10 million years ago, there was a huge reservoir, which scientists called the Sarmatian Sea. Gradually, the Sarmatian Sea with the growth of mountains was divided into a number of large sea-lakes cut off from the waters of the World Ocean: Aral, Caspian and Black. This last, due to the huge number of rivers flowing into it, began to desalinate. Over time, the entire fauna that lives in the ancient Black Sea Lake has become freshwater. But 8 million years ago there was a tremendous earthquake that created the Sea of Marmara and the Bosporus and Dardanelles and turned out to be fatal for the then inhabitants of the Black Sea. Masses of salt water poured from the Mediterranean into the Black Sea. The changes were so quick that the freshwater marine inhabitants of the Black Sea did not have time to adapt to them. A huge number of dead bodies sank to the bottom, and the process of their decomposition made the Black Sea exceptional, not like other seas: a hydrogen sulfide layer appeared, located below 150 m from the surface of the water.
This layer of hydrogen sulfide makes the vast expanses of the Black Sea unsuitable for life. Below 150 m, perhaps only sulfur anaerobic bacteria can exist, which by their vital activity only increase the percentage of hydrogen sulfide. This circumstance - the narrow layer in which fish is found, greatly toughens the life of such large and dangerous predators as sharks in the Black Sea. But hydrogen sulfide is not the only factor that blocks sharks. A large number of rivers and the narrowness of the Bosphorus Strait markedly desalinate the waters of this sea. Suffice it to say that the salinity of the Black Sea is half that of the Mediterranean. In addition, in winter, the surface of its water can cool to + 9 C, which is very uncomfortable for sharks living in the cool, but still not cold waters of the Atlantic. The poor food supply of the Black Sea is also unsuitable for sharks: large predators prefer large and flocked prey living in the depths of the waters, while the Black Sea is rich in small fish: hamsa, sprat, sardines, which live in the surface layers of water.
If we assume that some shark will swim in the summer from the Mediterranean to the Black Sea, then it is unlikely to get far from the Bosphorus due to the unsuitability of water and the scarcity of food. But still there are sharks in the Black Sea, and even two whole species. But do not rush to get scared! This is a katran shark, also called a dog shark due to the similarity of its muzzle, and a cat shark. These two species feed, like the Black Sea dolphins, on small fish, moving in small flocks. They do not eat people, although their mouths, again, like dolphins, are full of teeth. But people eagerly eat these small sharks: katran steaks are considered a big treat in the Crimea, and katran balyk is valued the same as sturgeon balyk, since this fish has almost no bones and its meat has an excellent taste.
However, it is still not worthwhile to clearly discard the danger of the shark in the Black Sea: the katran on the fin has a sharp spike that causes pain and can provoke inflammation of the wound. Although this is not characteristic of katranas and cat sharks , sometimes they swim in shallow water, and you can just step on them. In this case, the fish may startle the teeth with a fright. But such a case was recorded only once for all years of observation (in the 1970s on Evpatoria beach). The most dangerous animals for humans in the Black Sea are not sharks at all, but stingrays. Their backs are not equipped with simple spikes, but poisonous. A portion of the injected poison is not fatal for a person, but can seriously ruin his vacation, because the extremity from the bite swells. There are cases of loss of life (though not in the Black Sea) from a thorn in vital organs. But, in general, the Black Sea is considered the safest in comparison with others.