Bone fishes

Bony fish supernium belongs to the class of vertebrates and includes two more classes. One of them is represented by radiculiform fishes. It consists of more than 30 detachments and 500 families. The second - lobostopy fish (lungfish and cystopyrids).

Bony fishes live in all waters of the Earth - in salty and fresh, from both poles and to the equator. They are common both offshore and in the most inaccessible depths of the seas and oceans. As in bone, and in cartilaginous fish there are fins, that is, twin limbs. However, bone-cartilaginous fishes have significant distinctive features. First of all, it concerns the skeleton and the head: they have these parts completely bone. Exactly the same cover of these fish - scales, formed by bone plates.

Bone gill arches of these fish (five pairs thereof) are located on the sides of the pharynx. On them are the gills in the form of drooping petals. Nostrils are paired, in the inner ear there are semicircular canals (there are three of them). The structure of the fish of this superclass is distinguished by a gill cavity, covered with a bone gill cover. The swim bladder is located inside the body, in the upper part of the body. Grabbing jaws together with teeth form a mouth. The length of these fishes varies within wide limits: from 70 to 500-700 cm, respectively, their weight varies from several kilograms to one and a half tons.

For the first time, bone fishes appeared about 400 million years ago. Gradually, compared to other fish and vertebrate animals living on earth, they have reached the greatest diversity. Basically, bony fishes have a body shape resembling a torpedo. But there are also arrow-shaped fish (saury, sargan, barracuda, pike), ribbon-shaped (horns, moray eels, chains, eels) and globular (body, sea devils, puffers). And the sea horse is like the figure of a chess horse. Fins, both paired and unpaired, help the fish regulate the position of the body. The main organ of their displacement is the tail. Although some of the fish (for example, the moon, the sea needle, the triggerfish) change their location due to the wavy movements of the unpaired fins. On the head and on both sides of the body, the bony fishes have a so-called lateral line - a sensitive organ equipped with channel pores. It is peculiar only to animals that live in water. The lateral line helps them to perceive the strength and direction of the current. Thanks to this, even blinded fish can bypass obstacles and catch prey.

The back of almost all representatives of this superclass is colored darker than the sides, and the belly is the lightest part on the body of the fish. This coloring performs a protective function. The dark back is difficult to distinguish on the water surface, if viewed from above, from the air. And if you look at the fish from below, towards the sky, it is not easy to notice a light belly. Coloring depends on where and how deep the fish live. As a rule, its color repeats the surrounding environment. There is also a protective coloration of another type: bright circles, stripes on the body, spots on the tail, reminiscent of the eyes. All this disorientates both the enemy and the prey, as the shape of the body of the fish visually deforms, its contours are broken into parts. In addition, coloring serves as a means of identifying individuals of their species, including the other sex.

Some bony fish are able to jump out of the water, flying more than one hundred meters in the air. Many of them in the swim bladder or branchial cavity have even such devices that allow them to stay outside the water for long periods of time in moist tropical air. And in polypergous and lungfishes, the swim bladder consists of cells. This semblance of lungs allows them to breathe even atmospheric air.

Bony fishes play a huge role in the practical life of man. In many countries, fishing is one of the main branches of the economy. Fish is not only useful and tasty food. It serves as an excellent raw material for obtaining medicines (fat), poultry and livestock feed (fodder flour), fertilizers for earth (fat), glue, technical grease and other products that are used in the food and light industries.