Vertebrate Zoology - V. M. Konstantinov 2011

Chordates
Gnathostomes
Class Bony Fishes - Subclass Actinopterygii - Superorder Teleostei - Order Perciformes

Perciformes represent a vast and diverse group of about 6,500 marine and freshwater fish species, characterized by fin rays that are partially transformed into unsegmented sharp spines. Their pelvic fins are typically located beneath the pectoral fins or sometimes even further forward. The swim bladder does not communicate with the gut.

The Taxonomy of the order is complex, encompassing numerous suborders, families, and genera.

The family Percidae comprises 160 species within this order, many of which are of significant commercial importance. Notable representatives include pike-perches (Lucioperca), several species of which inhabit the basins of the Black and Caspian Seas. Some of these permanently reside in rivers, others in the sea, while others are semi-anadromous, migrating from rivers to the sea for feeding. Large individuals can reach weights of 10–12 kg. Perch (Perca) are widely distributed in the rivers and lakes of our country, leading a sedentary lifestyle. They reach a weight of 1 kg, rarely more, and a length of 50 cm, and in some regions serve as important commercial species.

The family Anabantidae consists of unique fish characterized by sac-like expansions of the gill cavity adapted for air breathing. These fish, such as the climbing perch (Anabas testudineus), are known to crawl onto land and even ascend trees. They inhabit fresh and brackish waters of tropical Africa, Asia, and the islands of the Malay Archipelago.

The family Scombridae comprises marine, predominantly tropical fish inhabiting the pelagic zone of open seas. Several species occur in Russia, distributed across the Baltic and Black Seas. They are highly migratory. An important commercial species (particularly in the Black Sea) is the Atlantic mackerel (Scomber scombrus).

Tunas (Thunnus) are taxonomically closely related to mackerels. Their sizes range from 40 cm to 3 m. They are distributed in the coastal and open waters of the World Ocean, ranging as far north as the coast of Scandinavia and as far south as the southern tips of Africa and Australia. Tunas are exceptionally energetic swimmers, capable of reaching speeds up to 90 km/h. Likely for this reason, their lateral body musculature features a highly developed Vascular System supplying Blood to these Muscles. Tunas are of major commercial importance.

The family Gobiidae includes small, mostly coastal marine and, less commonly, freshwater fish. They are characterized by pelvic fins fused into a sucking disc. They are bottom-dwellers, feeding on benthic invertebrates. During the breeding season, males of some species build nests where females deposit their eggs, which the males then guard. In Russia, they are primarily distributed in the southern seas and rivers. In the Black, Azov, and Caspian Seas, they are of commercial value.