Perciformes (lat. Perciformes) — a detachment of the class of bony fish. There are over 6000 species and about 150 families. Characteristic features: part fin rays has the form of undifferentiated acute spines, pelvic fins are usually located under the breast and sometimes in front of them; swim bladder not connected with the intestine.
The squad is part of the Perch family (Percidae), with 160 species, many of which have important commercial value. In particular, the Zander (Lucioperca), several species of which live in the basins of the Black and Caspian seas. Some of them live permanently in rivers, others in the seas, others are semi-anadromous fish coming from the rivers into the sea. Perch (Perca) are widely distributed in the rivers and lakes of Russia. Are also objects of the fishery.
The family of Labyrinth fishes (Anabantidae) is a kind of fish, characterized by the presence of saccular outgrowths of the Gill cavities, which are used for temporary breathing air. These fish, such as anabas (Anabas testudineus), often come out to shore and even climb trees. They live in fresh and brackish waters of tropical Africa, Asia and the Islands of the Malay archipelago. Some species, such as gourami, are used as aquarium fish. Continue reading
Our planet is inhabited by almost 20 thousand species of fish. About 1/10 of them are commercial. They give people a lot of valuable products: food, medicines, fertilizers for the agriculture, pet food, industrial oils, raw materials for light industry.
To move in the water, have to spend a lot of energy. Nature took care of the fish, giving their bodies zaradougou streamlined shape. The speed of the fish (scombridae, tuna, sharks) in its form and speed resemble that of a torpedo. The fastest fish is considered fish-sailfish, swordfish and Marlin, which reach speeds of up to 130 km/ h. The rate of freshwater fishes is typically lower, but in critical moments of his life, in the moment of impending danger or in the event of an attack on their prey, they can take a short term shot at a speed of 1-2 km /h. Good speed swimmers usually are found in rivers with current (sabrefish, Chub, nase, Dace, salmon). The speed of the fishes living in stagnant water far below, but they are more nimble, nimble (carp, bream, Rudd). Continue reading
The ocean abounds with excellent swimmers who, in the words of the famous German nineteenth-century biologist Ernest Haeckel, “free to find their own way”. They can resist the strong current of water and to choose their own way, different from the animals of the plankton. The combination of these actively swimming animals E. Haeckel called the nekton, which means “floating”. Technically, the nekton are aquatic snakes, birds, and animals, but here we will talk only about the two groups of nektonic organisms — the fish and cephalopod molluscs.
Important nektonic animals adaptations to life in the water column of the ocean, according to Professor Yuri Aleev are maintaining the body in a suspended state, creating a driving force, reducing the resistance of the counter flow of water, control the movement of the body, as well as in the ability to disguise and protection. Continue reading