Habits and distribution of Sichuan white turtle (cultured fish in the upper reaches of the Yangtze R

Sichuan white soft-shell turtle (Onychostoma angustistomata) belongs to the order Cypriniformes, Cyprinidae, subfamily Onychostoma angustistomata, and the genus Onychostoma angustistomata. Commonly known as: small mouth white nails, sharp mouth white nails, wax brown.

The body is long, the sides are flat, the caudal peduncle is slender, the abdomen is round, and the starting point of the dorsal fin is the highest point of the body. The head is short; the snout is round and blunt, slightly raised, with small white spots on the end of the snout, and an obvious oblique groove at the boundary of the preorbital bones. The mouth is wide, depressed, transversely cleft, and the corners of the mouth are slightly curved backward. The rear end of the upper jaw reaches below the rear edge of the nostril; the lower jaw has a sharp horny front edge; the upper lip is thin and smooth, covered by the snout. There are 2 pairs of barbels, the muzzle barbels are very short and the chin barbels are slightly longer, about 1/2-2/3 of the eye diameter. The back edge of the dorsal fin spines is serrated, the end is soft, and the outer edge of the dorsal fin is concave. The back is blue-gray, the abdomen is yellowish, there are black markings on the dorsal fin, the lower leaves of the caudal fin are bright red, and the other fins are also slightly red.

The living habits are similar to those of white turtles. They are both benthic fish and like to live in clear and gravelly flowing water. In early spring, groups move up the river, then retreat in autumn and winter, spending the winter at the bottom of the deep, rocky river. They often use the sharp horny edges of their mandibles to scrape food from rocks and other objects; their food is mainly algae and deposited humus, and the spawning period is usually earlier for larger individuals. After the parent fish reaches sexual maturity, they go up to rapids with lots of gravel and sandy beaches to lay eggs. The eggs often adhere to the sand and gravel at the bottom of the water for hatching. During the reproductive period, male fish have thick white beads on their snout, pectoral fins, and anal fins, and the even fins and anal fins are bright red; the beads on the female's snout are not obvious.

The Sichuan white turtle is distributed in the main branches and tributaries of the upper reaches of the Yangtze River, especially in the Jinsha River, Jialing River, Minjiang River, Dadu River and the middle and lower reaches of the Yalong River.

Sichuan white turtle is a medium-sized edible fish in the upper reaches of the Yangtze River. Although its output is not as good as that of white turtle, its meat quality is better and it is one of the fish that people in the production area like to eat daily. It can be domesticated and used as a pond culture object, and it can be reproduced in reservoirs to become an excellent species.

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