Shark is perhaps the most perfect predator of the water element, which is rightfully considered the master of the oceans. But lately, in order to satisfy his whims and various economic needs, man has been mercilessly catching and destroying these fish. This can lead to an inevitable violation of the ecology and a significant decrease in the number of sharks, as well as have a negative impact on marine flora and fauna. To avoid this, many countries are now introducing a partial or complete ban on their fishing.
Shark species
On the question of how many species of sharks exist in nature, it is impossible to answer exactly. Despite the fact that people exterminate them in large quantities, there are more than 400 species of this fish in the world, but these are only those that are known to scientists. They differ from each other not only in the shape and size of the body, but also in the way of life. Many will be surprised to learn that sharks are invertebrate fish. They don't really have bones! Instead, cartilage is a fairly tough fibrous tissue.
Shark is a collective name. The size of the smallest individual is only about a pencil, and it weighs about 200 g, and the largesta huge one can reach a length of 20 m and weigh up to 20 tons.
The most famous species are the great white, reef, hammerhead, tiger, blue and polar sharks, and the largest of them are giant and whale. The diet of the last two consists of plankton and small fish, which they swallow by filtering the water through many small teeth. The rarest white shark is considered the most dangerous and aggressive. In length, it can reach 5-6 m, but it happens that some individuals grow even up to 12 m.
Habitat
The entire World Ocean is inhabited by various types of sharks. As studies by scientists have shown, even in the deepest depressions living organisms live, including deep-sea sharks. Without them, it is hard to imagine the depths of the sea and ocean.
The population density of these predators is extremely uneven. Naturally, there are more of them where there is warm water and a large amount of food, namely off the coast.
World Ocean Population Density
The maximum number of species and individuals of sharks is concentrated in equatorial and equatorial waters. About 80% of marine predators living here live in the surface layers at a depth of no more than 200 m. This is due to the fact that these waters are extremely rich in food.
Moderately warm sea and ocean waters are much less inhabited by these fish - only 16% of the total number of sharks living on the planet.
Cold and arctic seas are very scarce. Therefore, there are very few predators here. They swim in these areas only inwarm season. Such cold-resistant species are polar (Greenland) and giant sharks.
Polar shark
It belongs to the genus Somniosidae, or Straight-mouthed. The polar shark is the largest representative of the catranoid order. Some individuals of this species reach more than 6 m in length and can weigh 1000 kg. But ichthyologists are sure that this is not the limit - 8 m in length and a weight of 2 tons is quite possible. Naturally, with such dimensions, she is inactive and does not quite correspond to the image to which everyone is accustomed, namely, an energetic, swift and ruthless predator. The polar shark is completely non-aggressive, and even if it gets into the net, it behaves calmly, like a log.
It looks ordinary and unattractive: the shape of the body is spindle-shaped, the color is from dark brown to brown with black-violet spots scattered all over the body.
Just by the name of this huge fish it becomes clear that it is found in the cold waters of the Atlantic and Arctic oceans. The habitat of sharks is quite wide. It can be found off the coast of Iceland, Norway and Greenland, as well as in the northern seas of Russia. In addition, it is found in the Hudson Bay and the Baffin Sea. In the waters of the Pacific Ocean, the polar shark is common in its northern part, and is also found in the Sea of Japan and the Sea of Okhotsk. I must say that she feels great in water with a temperature of +2 to +10 ⁰С.
Reef shark
On coral reefs, in lagoons, in shallow waters and on the border withreef sharks can often be observed in deep waters. They love clean clear water, so they very rarely go down to the very bottom. The optimal depth for them is from 8 to 40 m, but sometimes they swim almost to the very shore.
The reef shark is a relatively small species. Its length is a little over 2 m. It has a thin body with a flat wide head. It reaches its maximum length only by 25 years. Its color is brown or dark gray, sometimes with spots. The belly is always lighter than the back. While swimming, she makes significant wave-like movements, and can also lie on the bottom and pump water with gills, which most of her relatives cannot do. It can be said that she leads a settled life, as she keeps returning to the same shelter for several years.
Because the reef shark is relatively small, it often becomes the prey of larger and more aggressive species such as the tiger or whitetip.
Red Sea Sharks
Resorts located on the Red Sea coast are not considered too dangerous for ordinary bathers, divers or snorkelers. I must say that initially sharks do not consider humans as their food or prey. They prefer to keep a respectful distance from large crowds.
Sharks in the Red Sea were always found in abundance, as the water in it is warm. In addition, it communicates well with the ocean. For all the time, more than 40 species of these predators have been recorded in it. There are not so many of them off the coast of Egypt, most of the sharksprefers the territorial waters of Sudan. Also, not all species are dangerous to humans.
All sharks in the Red Sea, in fact, as elsewhere, are divided into pelagic and those that live in coastal waters. The former prefer open waters, the latter love shallow water, especially reefs. In Egypt, they can often be seen in Sharm el-Sheikh, in the Ras Mohammed nature reserve, as well as off the coast of Hurghada.
The most dangerous of all Red Sea shark species are black-winged, long-winged, zebra, mako and tiger sharks.
People and sharks
Now you can often see signs on ocean beaches warning not to go into the water. Over the past 10 years, cases of arbitrary and involuntary shark attacks on humans have become significantly more frequent.
Scientists who specialize in their study believe that this is mainly due to massive uncontrolled fishing - the main source of food for sharks. Therefore, in search of food, they move closer and closer to the coasts. In addition, some of the clashes occur due to the carelessness of people who go to the open sea and do not observe elementary precautions. Surfers and swimmers swim in areas where sharks live and hunt, which leads to inevitable collisions.
Reason for attack
Why do scary sharks attack people? This happens for several reasons. The first one is curiosity. All animals are naturally like this, including sharks. BUTthey show their curiosity through a trial bite. Just as a person touches an object of interest with his fingers, so these fish try everything on the tooth. Unfortunately, their touch is much more painful and unpleasant than the touch of fingers.
Food competition is the second reason for the attack. A large number of individuals nearby also claim an unknown object. Fearing for the interception of prey, the predator without any doubt attacks and snatches off some part of the flesh. This most often occurs during the so-called periods of food fever in sharks.
The third reason is the defense of the territory. Like animals, sharks protect their area of water from uninvited guests. Gray sharks are especially aggressive in protecting their territory, which, with their whole appearance, or rather, grimaces and poses, show that you had better leave, otherwise it will pounce without warning.
The last reason is cannibalism. At the same time, sharks deliberately attack people, as they have already tasted human flesh more than once. These cases, of course, are rare, but it is not possible to determine whether a predator is a cannibal by external signs.
Everyone knows that there are super-deep depressions in the seas and oceans, where a person has not yet been able to visit. Therefore, many mysteries and interesting and unusual inhabitants of the depths may well lurk there. The cold waters of the Arctic Ocean, in our opinion, are of little use for life, but there are many living creatures here, includingsharks.
