Geographical distribution and flora division of freshwater fishes in China

The division of geographical distribution of animals has always been one of the central issues that ichthyologists are concerned about. Various division methods have been described, and only three of the more influential division methods are introduced here.

Mr. Zhang Chunlin published an article "The Distribution of Freshwater Fishes in China" in Acta Geographica in September 1954. He believed that the division of freshwater fish areas in China is not exactly the same as that of terrestrial animals and plants, and should be divided into Heilongjiang, Northwest Plateau, Rivers The five regions including Plains, Dongyang and Nulan are more reasonable, and the characteristics of unique fish or dominant species in each region were analyzed.

1. Heilongjiang District: including the Heilongjiang, Songhua River, Ussuri River, Tumen River and Yalu River basins. The main groups of fish in the area are cold-tolerant species, such as three species of lampreys in the class Cylostomata, 10 species of the Salmonidae family, 2 species of the Salmonidae family, 1 species of the Smelt family, 1 species of the Pike family, and cod. Cold-water species such as burbot of the order Acipenseriformes, sturgeons of the order Acipenseriformes, and three-spined fish of the order Acipensiformes are all representative species unique to this area.

2. Northwest Plateau Area: This area includes Xinjiang, northern Tibet, Inner Mongolia, Qinghai, Gansu, Shaanxi, Shanxi and other places. The area is mainly plateau or mountainous, and the fish that inhabit it all have special adaptation conditions, such as being able to tolerate drought and alkali, or being able to live at the bottom of rapids, so there are relatively few species. Although this area has the fewest genera among all areas, Some special bead genera have adapted to the living environment and have a particularly large number of species, becoming dominant groups. For example, there are about 70 species of Schizothorax subfamily and 110 species of Loach subfamily, which constitute the endemic species of this area.

3. River plain area: This area is a large plain, including the middle and lower reaches of the Yangtze River, the lower reaches of the Yellow River, the Huaihe River Basin and the lower reaches of the Liaohe River. In addition to the trunks and tributaries of various rivers, there are also Boyang Lake, Dongting Lake, Taihu Lake, Chaohu Lake, etc. There are thousands of lakes of different sizes. Due to their flat terrain and slow water flow, the special adaptation characteristics of the main fish are that the general shape is that the body is flat on the side, the head and tail are both pointed, slightly spindle-shaped, and the chest, abdomen, buttocks, and tail fins are all well developed. Most species and genera of Cyprinidae are distributed in this area, such as carp, crucian carp, bream, grass, green carp, silver carp, bighead carp, red-eyed trout, tuna, bream, catfish, bream, trevally, drift fish, wheat ear fish, copper fish , stick fish, squid, etc. There are not only many species of carps in this area, but the individual production of their species is also very rich. It can be called the breeding center of carps in Asia.

4. Oriental Zone: This zone includes Guangdong, Guangxi, Hainan, eastern Yunnan, Guizhou, Fujian, Taiwan and other places. Most of the fish in the zone are subtropical and tropical fish that like warm temperatures. Fish in this area live in high mountains and rivers. Due to the rapid water flow, most of the fish that live in the area have suckers on their mouths or chests to survive in the rapids. This area is characterized by a wide variety of tropical organisms. The composition of its fish community is similar to that of Vietnam, Thailand, Myanmar, and India. Its representative species are mainly Danian subfamily, murrelet subfamily, and scorpion subfamily of the family Cyprinidae, Loach family, and the order Siluriiformes. Gryptozoonidae, Siboridae, Miscanthus family, Gryptozoonidae, Beardae family, Gyrozoonidae, Pyrozoonidae, etc.

5. Nulan District: This district is the area flowed by the Yarlung Zangbo River, Nu River, Lancang River, and Jinsha River, including southern and eastern Tibet, western Sichuan, and western Yunnan. The rivers in the area all flow in a north-south direction, allowing fish from the Eastern Ocean Region and the Northwest Plateau Area to coexist in this area through the exchange of river water. For example, species such as the Loach subfamily and the Loach family of the Loach family, the catfish genus of the Platypodidae family, the family Catidae, and the family Catidae, the eels of the Synbranchial order, and the snakehead species of the family Seridae are the same as those in the Oriental region; while the Schizothorax subfamily, Loach subfamily and other species are the same as those in the northwest plateau area. The mixture of fish in the two areas is a characteristic of the fish fauna in this area.

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