Sardinops sagax (Jenyns 1842)

The radiating bony striae on the operculum distinguish this fish from all other clupeoids in the area; in addition, species, of Sardinella and Herklotsichthys have two fleshy outgrowths on the hind margin of the gill opening and no series of dark spots along the flank (Amblygaster sirm has similar spots, but seems to be rare north of Taiwan Island, possibly to Okinawa); Clupea pallasii has the pelvic fin insertion before the dorsal fin origin and lacks spots on the flank; and Etrumeus teres and Dussumieria elopsoides lack scutes along the belly, also no spots.

To 24 cm standard length, usually 15 to 20 cm.

Coastalpelagic, forming large schools,migratory, moving northward in summer and tending also to move more inshore, the reverse as temperatures begin to drop.Feeds mainly on zooplankton, especially copepods, but also phytoplankton. Breeds from December to the beginning of May, earlier in the southern than the northern parts of range, in bays and in coastal parts of open sea; fishes mostly mature in second year.

One of the most important commercial fishes of Japan. The total catch for 1983 was 4 219 677 t. Record catches in 1934-39 (over 2 000 000 t) were succeeded by a sharp decline around 1941, with only partial recovery from 1945 and then further decline. Fluctuations in the catches and their relationship to the Kuroshio current were reviewed by Kawasaki (1979) and Watanabe, Honjo & Okutani (1979). The total catch reported for this species to FAO for 1999 was 515 477 t. The countries with the largest catches were Japan (351 207 t) and China (147 125 t). This species is mainly caught by "small pelagic purse seining", particularly "American boat operated purse seine".