Classification of fish: the basics of taxonomy and examples

Pisces are amazing inhabitants of the aquaticof the world. This is one of the most numerous and diverse groups of animals. Distinctive features of the structure, the classification of fish and the signs that form the basis for it will be considered in our article.

Fish Above Class: General Characteristics

Knowingly confident people are compared withthese animals. About them they say: "It feels like a fish in the water". And indeed, fish have the features of a structure that allowed them to master this habitat. These include a streamlined body shape, the presence of fins and scales, mucus-rich skin and gill respiration.

Basics of classification

These aquatic animals can be grouped intodifferent signs. First of all, the classification of fish according to the features of the structure is considered. Depending on this distinguish the class of cartilage and bony. Representatives of the latter have more progressive features of structure and number. Therefore within this systematic unit a number of orders are still singled out.

In terms of use, decorative andcommercial fish. The first people plant in aquariums and ponds as a decorative decoration. These are scalars, catfishes, neons, guppies, barbs and many others. A man fishes fish for consumption for food. Long since their meat and caviar are a favorite delicacy, and fat is a valuable medicinal product.

There is also an ecological classification of fish. It takes into account the conditions of their dwelling. It can be different types of water bodies: fresh, oceanic or marine.

Catch a big fish and ...

The classification of commercial fish takes into account alsothe size. From this sign depends on the method of catching and subsequent storage of raw materials. By weight and size distinguish between small, medium and large fish. Each of these groups has its valuable qualities. For example, sprats have excellent taste qualities and are widely used in the food industry, despite very small sizes.

For commercial fish gastronomic propertieshave a special significance. Therefore, they are distinguished by the amount of fat. For example, in cod, navaga and hake, this figure does not exceed 4%. Such species are considered to be lean, or lean. The highest indicator for this feature is considered to be sprat, mackerel, herring, saury, sturgeon and stellate sturgeon. Their fat content significantly exceeds the 8% mark.

In commodity science use the concepts of "species" and"family". Fish, the classification of fish are determined in trade practice most often on the basis of external signs. For example, the family Celery combines representatives, whose body is compressed from the sides, and scales loose. Such fish are devoid of a lateral line. They have a single dorsal fin, and the caudal has a characteristic notch. This family includes herring, sprat, tulka, sprats.

Anatomical classification of fish: table

It is generally accepted that when dividing fish into classes, only the structural features of the skeleton are taken into account. But it is not so. Basics of anatomical classification are shown in the table.

Symptoms for comparison	Class Cartilaginous fish	Class Bony fish
Structure of the skeleton	Completely formed by cartilaginous tissue	The structure of the skeleton includes bone tissue
Presence of gill covers	Absence, gill slits open outward by self-opening	Present, protect gills and participate in respiratory movements
Swimming bubble	Absent	There is
Type of fertilization and development	Internal, direct	External, indirect
Selection Features	The channels of the digestive, sexual and excretory systems are secreted into the cloaca	There is no cloak, each organ system opens with its own opening

Habitat

Classification of fish by habitat alsodefines several groups. The first include the marine inhabitants. This flounder, herring, halibut, mackerel, cod. Fresh fish are carp, sterlet, carp, burbot, crucian carp. They spend their entire lives in the same habitat, where their spawning takes place. The life activity of these ecological groups depends on the salinity of the water. So, if sea fish are transferred to fresh water, they will quickly die.

Feed fish

Classification of fish by habitat and imagelife includes another group, called Passage. It belongs to representatives of the supraclass, living in the seas, but going to fresh water for spawning. These are sturgeon and salmon fish. Such anadromous fishes are also called anadromous fish. But eels during spawning travel in the opposite direction - from rivers to the seas. These are typical representatives of catadromous fish.

Doing such a difficult path, representativespassages lose a lot of energy. They have to swim against the current, overcome rapids, waterfalls. All this time they do not eat, but expend their own supply of fat and nutrients. Therefore, many passing fish arrive at the breeding site, spawn and perish. On a permanent place of dwelling are returning already young individuals. Until now, it remains a mystery how fish find their way home. Others are able to spawn several times during life. During spawning with many fish external metamorphosis occurs. For example, at a pink salmon a hump grows on the back, jaws are bent.

So, the classification of fish is based on several signs. These include the features of the skeleton and internal structure, size, fat content, habitat, lifestyle, scope of use.