The side of saury is flat and long, Maebetaka, and gradually lower backwards; The back edge is straight, and the belly edge has serrated scales. The head is short and the side is flat and sharp. The kiss is blunt and round, protruding. The eyes are smaller, close to the snout. The interval between eyes is convex. There are 2 nostrils on each side, which are closer to the anterior margin than to the snout. Big mouth, lower position. The mouth cracks obliquely.
When young, the maxilla is short and extends backward to the vicinity of the gill cover; In adult fish, the maxilla extends backward to the base of pectoral fin, and the lower edge of maxilla has small serrations. 2 pieces of auxiliary maxilla. The teeth are small, and there are teeth in both jaws, vomerous bone and palatal bone. The gill holes are wide. Gill rake is slender. The left and right branchial operculum membranes are connected, but not the isthmus.
Extended data:
The food of saury in Qiantang River is mainly composed of shrimp, cladocera, fish, copepods, insects and other animals. There are only a few plant species such as filamentous algae in the diet. In food composition, cladocera and shrimp have the highest occurrence rate, but the number of shrimp far exceeds cladocera; Although the occurrence rate of copepods and insects exceeds 50%, the number is small; Although the occurrence rate of fish only accounts for 40.4%, the number is large, similar to that of shrimp, and the occurrence rate of rotifers and protozoa is low and the number is small.
Yangtze saury is a carnivorous fish. Juvenile fish and juvenile fish usually inhabit the upper and middle layers and mainly feed on small crustaceans and their larvae such as copepods and cladocera. Adult fish inhabit deeper waters and mainly feed on larvae or adults of large crustaceans such as shrimps and other large animals such as polychaetes, whitebait, meitong fish, yellow croaker, pomfret and squid.