Large yellow croaker

(1) Morphological characteristics: The body of the large yellow croaker is elongated and laterally compressed, with the dorsal and ventral margins forming a broad arc, and the caudal peduncle slender. Body length is 3.5-4.2 times body depth and 3.4-3.8 times head length. Head length is 3.9-5.0 times snout length and 3.-5.7 times eye diameter. Caudal peduncle length is 3.4-3.8 times caudal peduncle depth. The dorsal surface and upper sides are yellowish brown, the lower sides and ventral surface golden yellow, the dorsal and caudal fins grayish yellow, the pectoral and pelvic fins yellow, and the lips orange-red. The head is laterally compressed, large, pointed and blunt, with well-developed mucous cavities. The snout is bluntly pointed, larger than the eye diameter. The snout folds are complete, not divided into lobes; the suprasnout pores are quite small, 3 in number, sometimes absent; there are 5 rostral margin pores, the median rostral margin pore round and the lateral rostral margin pores slit-shaped. The eye is medium-sized, in a superior lateral position, located in the anterior half of the head. The interorbital space is rounded and protruding, larger than the eye diameter. There are 2 nostrils on each side; the anterior nostril is small and round; the posterior nostril is large and oblong. The mouth is large, terminal, and obliquely cleft. The lower jaw projects slightly, with a tumor-like protuberance at the symphysis. The posterior end of the maxilla nearly reaches above the posterior margin of the eye. The teeth are fine and sharp; the upper jaw teeth are in multiple rows, the outer row enlarged, with the anterior lateral several teeth largest; the lower jaw teeth are in 2 rows, the inner row larger, and the 2 teeth behind the tumor-like protuberance at the lower jaw symphysis are larger, with their tips directed inward. There are 6 mental pores, inconspicuous, with the median mental pore and inner mental pores arranged in a square, and outer mental pores also present. There are no mental pores. The gill opening is large. The margin of the preopercle bears fine serrations. There are 2 flat spines on the upper posterior part of the opercle. The gill membrane is not connected to the isthmus. There are 7 branchiostegal rays. Pseudobranchs are present. The gill rakers are fine and long, about 2/3 the eye diameter. Gill rakers 9+16-17. The head and anterior part of the body are covered with cycloid scales, and the posterior part of the body with ctenoid scales. More than 2/3 of the dorsal fin ray portion and the anal fin membrane are covered with irregular scales, and the caudal fin is covered with scales. There are 8-9 rows of scales between the dorsal fin and the lateral line. The scales on the lower part of the sides of the body each usually have a golden yellow gland. The lateral line is complete, slightly curved anteriorly and straight posteriorly, extending to the end of the caudal fin. The dorsal fin is continuous, with a deep notch between the spinous and ray portions, its origin above the base of the pectoral fin, with 9-10 fin spines; the first fin spine is short and weak, and the third fin spine is the longest. The anal fin has 2 fin spines, its origin below the middle of the dorsal fin ray portion; the length of the second fin spine equals or is slightly greater than the eye diameter. The pectoral fins are pointed and long, longer than the pelvic fins. The pelvic fins are relatively small. The caudal fin is pointed and long, slightly wedge-shaped. The swim bladder is large, with the anterior end round, not protruding on the sides to form lateral sacs, and with 31-33 pairs of lateral appendages on the sides of the swim bladder; each lateral appendage has a dorsal branch and a ventral branch, the ventral branch divides into upper and lower small branches, and the lower small branch further divides into anterior and posterior small branches, the anterior and posterior small branches being equal in length, parallel to each other, and extending along beneath the peritoneum to the ventral surface. The otolith is somewhat chevron-shaped, with a tadpole-shaped impression on the ventral surface. Vertebrae generally 26.

(2) Ecological habits: The large yellow croaker prefers to inhabit the middle and lower layers of coastal shallow sea areas with a water depth within 60 m, and during reproduction it gathers in schools in the middle and upper layers. It is a warm-temperate, schooling, migratory neritic fish. It dislikes strong light and often concentrates in turbid water areas with relatively low transparency, and mostly rises to the surface at dawn, dusk, or during spring tides. It has a wide diet and is a predatory fish, with prey types numbering as many as a hundred. Juveniles mainly feed on zooplankton such as copepods, mysids, and krill. Adults mainly feed on various small fishes, shrimps, crabs, mysids, and so on. Feeding intensity decreases during the reproductive period. The large yellow croaker also has a strong sound-producing ability, and during the reproductive period the spawning population is accompanied by strong "dong dong" and "gu gu" calls. When fish schools are dense, the sounds produced are like boiling water or the soughing of pines. The spawning grounds of the large yellow croaker are mostly near estuaries or in nearshore shallow-water areas of islands and inner bays, with water depth generally not exceeding 20 m and the substrate being soft mud or muddy sand. The large yellow croaker can spawn multiple times in its life, with the main spawning seasons being spring and autumn, and the spring tide period being its ovulation period. Fecundity is 100,000-1,100,000 eggs, generally 200,000-500,000 eggs. The large yellow croaker is mainly distributed in the South China Sea, the Taiwan Strait, the East China Sea, and the southern Yellow Sea, with the highest yield in Zhejiang.