A, yellow croaker (yellow croaker), the yellow croaker family, born in the East China Sea, there are two hard stones in the head of the fish, called the fish brain stone, so it is also known as the stone head of the fish. Yellow croaker is divided into big yellow croaker and small yellow croaker, belongs to the warm temperature group swimming fish, often inhabits in the water depth of 60 meters or less in the middle and lower layers of the sea, its reproductive season in spring and fall. It is one of the important economic fish in China and has long been favored by consumers. However, due to overfishing, the resources have been seriously damaged.
Second, the big yellowtail, body nearly rectangular and side flat, dorsal and abdominal margins of the front convex and the rear is low. Body length of about 30 centimeters. The head is large and laterally compressed, with a rounded snout. Eyes equal in size and laterally superior; interocular septum wide and slightly convex. Nostrils 2 on each side, anterior nostrils round and small, posterior nostrils elongate, larger, close to eyes. Mouth anterior, broad and oblique. Upper and lower jaws equal, lips thin; maxilla retractable. Margin of anterior gill cover bone serrulate, posterior end of gill cover bone with a flat spine. Gill pores large, gill cover membrane not connected to isthmus. Gill rakers longer. Scales pectinate, lateral shallow scales 57; lower lateral line scales larger than upper lateral line scales. Dorsal and anal fins covered with small rounded scales on more than 2/3 of fin rays. Lateral line more curved anteriorly, straighter posteriorly. Dorsal fins VIII-X31, beginning above the beginning of the pectoral fins. Anal fin II 9, beginning about opposite middle of dorsal fin rays, pectoral fin 15, beginning behind gill cover. Ventral fin smaller than pectoral. Caudal fin cuneate. Body dorsal side grayish yellow, lower side golden yellow; dorsal and caudal fins grayish yellow, pectoral, ventral and anal fins yellow. Mostly active in the middle and lower layers of seawater, with migratory habits. ②Small yellowtail, similar in shape to the large yellowtail but small. The body length is about 20 centimeters. Lateral scales 60 to 63. dorsal fin IX 34 to 36, the beginning of the pectoral fin and the beginning of the opposite. Anal fin II 9, starting slightly behind the middle of the dorsal fin rays. Pectoral fin 19, long and pointed, ending beyond the end of the ventral fin. Ventral fin slightly shorter than pectoral fin. Caudal fin cuneate. Dorsal side of body grayish brown, sides and ventral side yellow, dorsal fin margin grayish brown. It has migratory habits.
Three, distribution range map wintering in the deep sea, spring to coastal migration, March to June after spawning, scattered in the offshore bait, mainly to mysis shrimp, shrimp, and small fish for food, the end of the fall to return to the deep sea. The small yellowtail has a planktonic benthic and swimming animal diet, small food selectivity, mainly feeding on zooplankton, fish and shrimp, of which zooplankton copepods are the main ones, the fish are mainly _ tigerfish, shrimp are hairy shrimp, mysid shrimp, ridley-tailed white shrimp and drum shrimp, etc. The small yellowtail has a planktonic benthic and swimming animal diet. In the southern Yellow Sea, the northern waters of the East China Sea, the small yellowtail mainly feeds on swimming animals, but in different life periods (overwintering, spawning and baiting) feeding intensity is different, of which the overwintering period (January to March) feeding intensity is the weakest, spawning (April to May) in the middle, baiting (June to December) the most vigorous.