Herring scad

Distributed across the Indo-Pacific. Uncommon around mainland Japan, but found in southern Okinawa. They form schools from coastal to offshore areas and feed on plankton.  It is a medium-sized fish that reaches 40 to 50cm in length. In Okinawa, it is called Gatsun and is not distinguished from other small to medium-sized jacks. This species has an adipose eyelid that is slightly opaque and the Japanese name Mabutashimaaji derives from this feature. They are a very delicious popular food. A young fish will sometimes let out a blueish purple liquid from its anus which can surprise people transporting the fish after they are caught.