Karasumi is a food product made by salting mullet roe pouch and drying it in sunlight.

A theory suggests that it got its name from its resemblance to the blocks of sumi (inkstick) imported from China (Kara) for use in Japanese calligraphy.

It is a speciality of Nagasaki and along with salt-pickled sea urchin roe and Konowata one of the "three chinmi of Japan".

The town of Donggang in Taiwan specializes in the delicacy, called wuyutsu (Chinese: 烏魚子).

Mullet fishing in Taiwan can be traced back to when the island was under Dutch colonial rule.